ES2673875T3 - Air conditioning - Google Patents

Abstract

Air conditioning unit (1) that has a refrigerant circuit (10) configured by connecting a compressor (21), an outdoor heat exchanger (23), a first expansion valve (24), a tank (25), a valve opening / closing (26, 27), and an indoor heat exchanger (41); wherein a full closure expansion valve that is fully closed by a needle (61) that sits on a valve seat (55) is used as the first expansion valve (24), and the first expansion valve (24 ) is provided in the refrigerant circuit (10) in the first arrangement state in which the refrigerant in the reservoir (25) flows inward from the forward direction side of the valve seat (55) needle, and out to the needle retract direction side of the valve seat (55) through a gap between the needle and the valve seat (55), where the needle advance direction is the direction in the that the needle moves when the needle is seated in the valve seat (55), and the direction of the needle back is the direction in which the needle moves when the needle is retracted from the valve seat (55); The first expansion valve (24) provided in the refrigerant circuit (10) in the first state of arrangement comprises a spring (62) for urging the needle seated on the valve seat (55) in the direction of advance of the needle when The valve is fully closed, and is configured so that the needle is released from being seated in the valve seat (55) when the biasing force of the spring (62) in the forward direction of the needle is exceeded by a force that pushes the needle in the needle backward direction, as generated by the back pressure valve opening pressure difference, which is the difference between the pressure of the refrigerant in a space (52a) on the side of the reverse direction of the valve seat needle (55) and the pressure of the refrigerant in a space (52b) on the forward direction side of the valve seat (55) needle; and the first expansion valve (24) is provided in a part of a cooling liquid pipe (35) that is located between the outdoor heat exchanger (23) and the tank (25); characterized in that the tank (25) is provided between the first expansion valve (24) and the opening / closing valve (26, 27).

Description

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DESCRIPTION

Air conditioning Technical field

The present invention refers to an air conditioner, and in particular an air conditioner comprising a refrigerant circuit configured by connecting a compressor, an outdoor heat exchanger, a first expansion valve, a reservoir, a valve opening / closing, and an indoor heat exchanger.

Prior art

In the past, there have been air conditioners that have a refrigerant circuit in which expansion valves are provided on the upstream and downstream sides of a tank, as shown in Patent Bibliography 1 (publication without Japanese Patent exam open for public inspection No. H10-132393). Specifically, the air conditioner has a refrigerant circuit configured by connecting a compressor, a heat exchanger, a first expansion valve, a reservoir, a second expansion valve (an opening / closing valve), and a heat exchanger. indoor heat

Summary of the Invention

When full-closing expansion valves are used, such as the expansion valves, provided on the upstream and downstream sides of the reservoir, there is a risk of liquid stagnation inside the reservoir when the two expansion valves become They are completely closed. The term "liquid stagnation" in this document refers to a state in which a predetermined space in the refrigerant circuit is filled with coolant and the coolant is sealed within said predetermined space, and problems such as breakage of the equipment that is in the predetermined space due to an increase in temperature. Specifically, the part of the refrigerant circuit between the two expansion valves that the tank includes is filled with coolant, where the coolant is sealed in this part, and there is a risk of problems such as an increase in the temperature that it causes the deposit and other elements of the equipment that constitute this part to be broken. In the configuration of the patent literature 1, an injection tube is provided, but there is still a risk of liquid stagnation in the tank when the three expansion valves are completely closed also in this case. Even in a configuration where a full shut-off expansion valve (for example, a first expansion valve) is provided on either from the upstream side or the downstream side of the reservoir, and a check valve is provided closing of the liquid side on the other side between the upstream side or the downstream side of the reservoir, there is still a risk of liquid stagnation in the reservoir when the first expansion valve and the liquid side closure valve is They are completely closed. WO 2007/083794 A1 discloses an air conditioning apparatus consisting of a refrigerant circuit configured by connecting a compressor, an outdoor heat exchanger, a first expansion valve, a reservoir, an opening / closing valve, and an exchanger Indoor heat A full closing expansion valve is used, which is completely closed by a needle that sits in a valve seat as the first expansion valve, and the first expansion valve is provided in the refrigerant circuit in a first disposition state in which a coolant inlet flow from the side in the direction of needle advance of the valve seat occurs, and an outflow to the side in the direction of retraction of the needle from the valve seat through a gap between the needle and the valve seat, and where the direction of retraction of the needle is the direction in which the needle moves when the needle retracts from the valve seat. The first expansion valve provided in the refrigerant circuit in the first state of arrangement, has a spring to drive the needle that sits on the valve seat to the direction of advance of the needle, when said valve is completely closed, and it is configured so that the needle is released from its seat in the valve seat when the impulse force of the spring in the direction of advance of the needle is exceeded by a force that pushes the needle in the direction of retraction of the needle, according to it is generated by a difference in the opening pressure of the back pressure valve, which is the difference between the pressure of the refrigerant in a space on the side of the retraction direction of the needle of the valve seat and the pressure of the refrigerant in a space on the forward direction side of the valve seat needle. Wo 2007/083794 A1 discloses an air conditioning apparatus according to the preamble of claim 1. To avoid said liquid stagnation in the reservoir, a liquid stagnation prevention tube must be provided, to allow the refrigerant to escape into any time from the upper space of the tank, but because providing said liquid stagnation prevention tube raises the cost and causes problems with the installation space, it would be preferable to avoid the stagnation of liquid in the reservoir without providing the prevention tube of liquid stagnation.

An object of the present invention is to provide an air conditioning apparatus having a refrigerant circuit configured by connecting a compressor, an outdoor heat exchanger, a first valve of

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expansion, a reservoir, an opening / closing valve, and an indoor heat exchanger, where liquid stagnation in the reservoir can be avoided using full-closing expansion valves, without providing a liquid stagnation prevention tube .

An air conditioner according to a first aspect of the present invention is an air conditioner defined by the appended claim 1.

When a full closing expansion valve is used as the first expansion valve, and there is an increase in the refrigerant pressure in the part of the refrigerant circuit between the expansion valve and the opening / closing valve that includes the reservoir, the refrigerant in the part of the refrigerant circuit between the first expansion valve and the opening / closing valve that includes the tank must be able to be left in the rest of the refrigerant circuit in order to avoid the stagnation of liquid, without providing a stagnation prevention tube of liquid, even when the first expansion valve and the opening / closing valve are completely closed.

In view of this, the first expansion valve in the present patent is provided in the refrigerant circuit in a first state of arrangement in which the refrigerant in the reservoir flows inward from the direction of the needle forward direction of the valve seat, through a gap between the needle and the valve seat, and outward toward the backward direction side of the valve seat, as described above. In this way, a force will act to push the needle in the direction of backward movement of the needle when there is a difference in the opening pressure of the back pressure valve, which is the difference between the pressure of the refrigerant in the space on the side of the reverse direction of the valve seat needle and the refrigerant pressure in the space of the forward direction side of the valve seat needle, when the first expansion valve is fully closed. The force that pushes the needle in the reverse direction of the needle due to this pressure difference of the back pressure valve is used to provide a configuration in which the first expansion valve provided in the refrigerant circuit in the first state of arrangement, it is provided with a spring to propel the needle seated in the valve seat in the direction of advance of the needle when the valve is completely closed, and when the force that pushes the needle in the direction of retraction of the needle, Due to the difference in the opening pressure of the back pressure valve, the force of the spring is exceeded in the direction of advance of the needle, the needle is released from its seat in the valve seat. This produces a configuration in which the refrigerant in the part of the refrigerant circuit between the first expansion valve and the opening / closing valve that includes the receiver can be passed to the outdoor heat exchanger when there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit between the first expansion valve and the opening / closing valve that includes the tank.

Therefore, in the refrigerant circuit of this air conditioner, configured by connecting the compressor, the outdoor heat exchanger, the first expansion valve, the receiver, the opening / closing valve, and the indoor heat exchanger, Liquid stagnation in the reservoir can be avoided without providing a liquid stagnation prevention tube, despite using a full shut-off expansion valve as the first expansion valve.

An air conditioner according to a second aspect is the air conditioner according to the first aspect, wherein the opening / closing valve is a liquid side closing valve.

Specifically, the refrigerant circuit is configured with a first full shut-off expansion valve provided on one of the upstream and downstream sides of the reservoir, and a shut-off valve provided on the other between the upstream and downstream sides of the tank. Deposit. Therefore, when the first expansion valve and the liquid side shut-off valve are completely closed, there is a risk of liquid stagnation in the reservoir.

In view of this, the first full shut-off expansion valve, in the present patent, is provided in the refrigerant circuit in the first state of disposition in which the receiver refrigerant flows inward from the direction side of advance the needle of the valve seat, and outward toward the reverse direction of the needle of the valve seat through a gap between the needle and the valve seat, as described above. Therefore, a configuration can be achieved in which the refrigerant in the part of the refrigerant circuit between the first expansion valve and the liquid side shut-off valve that includes the reservoir can be left to the outdoor heat exchanger when there is a increase in coolant pressure in the part of the coolant circuit between the expansion valve and the liquid side shut-off valve that includes the reservoir.

Therefore, in the refrigerant circuit of this air conditioner, configured by connecting the compressor, the outdoor heat exchanger, the first expansion valve, the reservoir, the liquid side shut-off valve, and the heat exchanger of inside, liquid stagnation in the tank can be avoided without

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provide a liquid stagnation prevention tube, despite using a full shut-off expansion valve as the first expansion valve.

An air conditioner according to a third aspect is the air conditioner according to the first aspect, wherein the opening / closing valve is a second expansion valve, and the second expansion valve is a valve of Full closing expansion that is completely closed by a needle that sits in the valve seat. This second expansion valve in this case is provided in the refrigerant circuit in a first state of arrangement in which the refrigerant in the reservoir flows inward from the direction of the forward direction of the needle of the valve seat, and outward towards the backward direction side of the valve seat needle, through a gap between the needle and the valve seat, where the direction of advance of the needle is the direction in which the needle moves when the needle is seated in the valve seat, and the needle reverse direction is the direction in which the needle moves when the needle retracts from the valve seat. The second expansion valve provided in the refrigerant circuit in the first disposition state has a spring to drive the needle seated in the valve seat in the direction of advance of the needle when the valve is completely closed, where the second expansion valve It is configured so that the needle is released from the seat on the valve seat when the impulse force of the spring in the direction of advance of the needle is exceeded by a force that pushes the needle in the direction of backward movement of the needle, according to it is generated by a difference in the opening pressure of the back pressure valve, which is the difference between the pressure of the refrigerant in a space on the backward direction side of the needle of the valve seat and the pressure of the refrigerant in a space on the forward direction side of the valve seat needle.

Specifically, the refrigerant circuit in the present patent is configured with a first full shut-off expansion valve, provided on one of the upstream and downstream sides of the reservoir, and a second expansion valve provided on the other between the sides. upstream and downstream of the reservoir. Therefore, when the full shut-off expansion valves are used as the first and second valves and there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit between the two expansion valves that include the reservoir they must be able to be left in the remainder of the refrigerant circuit to prevent liquid stagnation in the tank without providing a liquid stagnation prevention tube, even when the two expansion valves are completely closed.

In view of this, the second expansion valve is provided in the refrigerant circuit in the first state of disposition in which the refrigerant of the receiver flows inwardly from the direction of forward direction of the needle of the valve seat, and outward toward the backward direction side of the valve seat needle through a gap between the needle and the valve seat, as described above. In the first expansion valve and the second expansion valve provided in the refrigerant circuit in the first disposition state, a force acts in this way to push the needle in the direction of needle retraction when the opening pressure difference occurs of the back pressure valve, which is the difference between the pressure of the refrigerant in a space on the backward direction side of the valve seat needle and the pressure of the refrigerant in a space on the side of the forward direction of the valve seat needle when the valve is completely closed. The force that pushes the needle in the reverse direction of the needle due to the difference in opening pressure of the back pressure valve is used to provide a configuration in which the first expansion valve and the second expansion valve provided in The refrigerant circuit in the first state of disposition is provided with a spring to drive the needle seated in the valve seat in the direction of advance of the needle when the valve is completely closed, and when the force that pushes the needle in the direction of needle retraction due to the difference in the opening pressure of the back pressure valve exceeds the impulse force of the spring in the direction of advance of the needle, the needle is released from its seat in the valve seat. This makes it possible to produce a configuration in which the refrigerant in the part of the refrigerant circuit between the two expansion valves that include the tank, can be passed to the outdoor heat exchanger and / or the indoor heat exchanger when there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit between the two expansion valves that the tank includes.

Therefore, the refrigerant circuit of this air conditioner, configured by connecting the compressor, the outdoor heat exchanger, the first expansion valve, the reservoir, the second expansion valve, and the indoor heat exchanger, can be avoided liquid stagnation in the reservoir without providing a liquid stagnation prevention tube, despite using the full shut-off expansion valves such as the first expansion valve and the second expansion valve.

An air conditioner according to a fourth aspect is the air conditioner according to any of the first to the third aspect, where the impulse force of the spring when the valve is completely closed is adjusted so that the total sum of the difference in the opening pressure of the back pressure valve and a maximum saturation pressure is equal to, or less than the test pressure of the tank, where the maximum saturation pressure is the saturation pressure of the refrigerant corresponding to the maximum value

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of the atmospheric temperature at the location where the tank, the first expansion valve, and the opening / closing valve are installed.

Therefore, the impulse force of the spring when the valve is completely closed is adjusted in the present patent so that the total sum of the pressure difference of the back pressure valve is equal to or less than the test pressure of the tank , where the maximum saturation pressure is the saturation pressure of the refrigerant corresponding to the maximum value of the atmospheric temperature at the location where the first expansion valve and the opening / closing valve are installed, as described above. Even assuming conditions of an atmospheric temperature so high that the refrigerant in the part of the refrigerant circuit between the first expansion valve and the opening / closing valve that includes the tank increases in pressure to the maximum saturation pressure, the force generated by The difference in opening pressure of the back pressure valve to push the needle in the direction of backward movement of the needle will thereby exceed the impulse force of the spring in the direction of advance of the needle before the pressure of the needle is exceeded. proof of deposit, and the needle can be released from its seat in the valve seat. Therefore, the refrigerant in the part of the refrigerant circuit between the first expansion valve and the opening / closing valve that includes the reservoir can be passed to the outdoor heat exchanger and / or the indoor heat exchanger before that the test pressure of the reservoir is exceeded, and the stagnation of liquid in the reservoir can be avoided.

Therefore, in this air conditioner, liquid stagnation in the tank can be properly avoided while taking into account the test pressure of the tank.

An air conditioner according to a fifth aspect is the air conditioner according to the first aspect, wherein the refrigerant circuit also has a gas purge valve for purging refrigerant from the upper space of the tank, and the valve Gas purge is a full-closing expansion valve that is completely closed by a needle that sits in a valve seat. The gas purge valve in this case is provided in the refrigerant circuit in a first state of disposition in which the refrigerant in the tank flows inward from one side of the direction of advance of the needle of the valve seat, and outward toward the backward direction side of the valve seat needle through a gap between the needle and the valve seat, where the needle advance direction is the direction in which the needle moves when the Needle sits in the valve seat, and the needle backward direction is the direction in which the needle moves when the needle moves back from the valve seat. The gas purge valve provided in the refrigerant circuit in the first state of arrangement has a spring to drive the needle seated in the valve seat in the direction of advance of the needle when the valve is completely closed, where the valve Gas purge is configured so that the needle is released from its seat in the valve seat when the impulse force of the spring in the direction of advance of the needle is exceeded by a force that pushes the needle in the reverse direction of the needle as generated by a difference in the opening pressure of the back pressure valve, which is the difference between the pressure of the refrigerant in a space on the backward direction side of the needle of the valve seat and the pressure of the refrigerant in a space on the side of the forward direction of the valve seat needle.

Specifically, the refrigerant circuit in the present patent is configured with a first full shut-off expansion valve provided on one side between upstream and downstream of the reservoir, an opening / closing valve provided on the other between the sides upstream and downstream of the tank, and a full shut-off gas purge valve provided in the tank. Therefore, when the full shut-off expansion valves are used as the first expansion valve and the gas purge valve, and there is an increase in the refrigerant pressure in the part of the refrigerant circuit between the first expansion valve, the opening / closing valve, and the gas purge valve that includes the reservoir, the refrigerant in the part of the refrigerant circuit between the first expansion valve, the opening / closing valve, and the gas purge valve that includes the The tank must be allowed to pass through the rest of the refrigerant circuit to prevent liquid stagnation in the tank without providing a liquid stagnation prevention tube, even when the first expansion valve, the opening / closing valve, and the purge valve of gas are completely closed.

In view of this, the gas purge valve is provided in the refrigerant circuit in the first state of arrangement in which the refrigerant in the reservoir flows inward from the direction of the needle advance direction of the valve seat, and outward toward the backward direction side of the valve seat needle through a gap between the needle and the valve seat, as described above. In the first expansion valve and the gas purge valve provided in the refrigerant circuit in the first disposition state, a force thus acts to push the needle in the direction of needle retraction when a pressure difference occurs opening of the back pressure valve, which is the difference between the pressure of the refrigerant in a space on the backward direction side of the needle of the valve seat, and the pressure of the refrigerant in a space on the side of the direction of advance of the needle of the valve seat when the valve is completely closed. The force that pushes the needle in the reverse direction of the needle due to this pressure difference of the back pressure valve is used to provide a configuration in which the first expansion valve and / or the gas purge valve provided in the circuit

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refrigerant in the first state of arrangement, it is provided with a spring to drive the needle seated in the valve seat in the direction of advance of the needle when the valve is completely closed, and when the force that pushes the needle in the direction Reversing the needle due to the difference in the opening pressure of the back pressure valve exceeds the force of the spring in the direction of advance of the needle, the needle is released from its seat in the valve seat. This produces a configuration in which the refrigerant in the part of the refrigerant circuit between the first expansion valve, the opening / closing valve, and the gas purge valve that includes the reservoir can be passed to the outdoor heat exchanger , the indoor heat exchanger, and / or the compressor when there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit between the first expansion valve, the opening / closing valve, and the gas purge valve that It includes the deposit.

Therefore, in the refrigerant circuit of this air conditioner, configured by connecting the compressor, the external heat exchanger, the first expansion valve, the tank, the opening / closing valve, the indoor heat exchanger, and the gas purge valve, liquid stagnation in the tank can be avoided without providing a liquid stagnation prevention tube, despite using full shut-off expansion valves, such as the first expansion valve and the gas purge valve .

An air conditioner according to a sixth aspect is the air conditioner according to the fifth aspect, wherein the opening / closing valve is a liquid side closing valve.

Specifically, the refrigerant circuit is configured with a first expansion valve provided on one of the upstream and downstream sides of the reservoir, and a liquid side shut-off valve provided on the other between the upstream and downstream sides. down the deposit. Therefore, when the first expansion valve and the liquid side shut-off valve are completely closed, there is a risk of liquid stagnation in the reservoir.

In view of this, the first full shut-off expansion valve and the gas purge valve in the present patent are provided in the refrigerant circuit in the first state of arrangement in which the refrigerant in the tank flows inward from the side of the forward direction of the needle of the valve seat, and outward towards the side of the reverse direction of the needle of the valve seat through a gap between the needle and the valve seat, as it has been previously described. Therefore, a configuration can be achieved in which the refrigerant in the part of the refrigerant circuit between the first expansion valve, the liquid side shut-off valve, and the gas purge valve that includes the reservoir can be passed into the outdoor heat exchanger and / or the compressor when there is an increase in the refrigerant pressure in the part of the refrigerant circuit between the first expansion valve, the liquid side shut-off valve, and the gas purge valve that It includes the deposit.

Therefore, in the refrigerant circuit of this air conditioner, configured by connecting the compressor, the outdoor heat exchanger, the first expansion valve, the reservoir, the liquid side shut-off valve, the indoor heat exchanger , and the gas purge valve, liquid stagnation in the tank can be avoided without providing a liquid stagnation prevention tube, despite using full shut-off expansion valves such as the first expansion valve and the purge valve Of gas.

An air conditioner according to a seventh aspect is the air conditioner according to the first aspect, where the opening / closing valve is a second expansion valve, the refrigerant circuit also has a gas purge valve to purge the refrigerant from the upper space of the tank, and the second expansion valve and the gas purge valve are full-closing expansion valves that are each completely closed by a needle that sits in a valve seat. The gas purge valve in this case is provided in the refrigerant circuit in a first disposition state in which the coolant in the tank flows inward from the direction of the forward direction of the needle of the valve seat, and towards out to one side of the backward direction of the valve seat needle through a gap between the needle and the valve seat, where the direction of advance of the needle is the direction in which the needle travels when The needle sits in the valve seat, and the needle backward direction is the direction in which the needle moves when the needle retracts from the valve seat. The second expansion valve and / or the gas purge valve provided in the refrigerant circuit in the first disposition state, has a spring to propel the needle seated in the valve seat in the direction of advance of the needle when the valve it is completely closed, where the second expansion valve and / or the gas purge valve are configured so that the needle is released from its seat in the valve seat when the force of spring impulse in the forward direction of The needle is exceeded by a force that pushes the needle in the direction of backward movement of the needle as it is generated by a pressure difference of opening of the back pressure valve, which is the direction of advance of the needle that is exceeded by a force which pushes the needle in the direction of retraction of the needle as generated by a pressure difference of opening of the back pressure valve, which is the difference between l Coolant pressure in a space on the backward direction side of the valve seat needle and coolant pressure in a space on the side of the forward direction of the valve seat needle.

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Specifically, the refrigerant circuit in the present patent is configured with a first and a second full shut-off expansion valve provided on the upstream and downstream sides of the reservoir, and a full shut-off gas purge valve provided on the Deposit. Therefore, when the full shut-off expansion valves are used as the first expansion valve, the second expansion valve, and the gas purge valve and there is an increase in the refrigerant pressure in the part of the refrigerant circuit between the first expansion valve, the second expansion valve, and the gas purge valve that includes the reservoir, the refrigerant in the part of the refrigerant circuit between the first expansion valve, the second expansion valve and the gas purge valve which includes the reservoir must be able to be passed to the rest of the refrigerant circuit to avoid the stagnation of liquid in the reservoir without providing a liquid stagnation prevention tube, even when the first expansion valve, the second expansion valve and the valve Gas purges are completely closed.

In view of this, at least one of the second expansion valve, and the gas purge valve is provided in the refrigerant circuit disposed in the first state in which refrigerant flows inwards from the direction of travel side of the needle of the valve seat, and outward toward the recoil side of the needle of the valve seat through the gap between the needle and the valve seat, as described above. In the first expansion valve, the second expansion valve and / or the gas purge valve provided in the refrigerant circuit in the first disposition state, a force thus acts to push the needle in the direction of backward movement of the needle when the opening pressure difference of the back pressure valve takes place, which is the difference between the pressure of the refrigerant in a space on the backward direction side of the needle of the valve seat and the pressure of the refrigerant in a space on the forward direction side of the valve seat when the valve is completely closed. The force that pushes the needle in the reverse direction of the needle due to this pressure difference of the back pressure valve is used to provide a configuration in which the first expansion valve, the second expansion valve, and / or the gas purge valve provided in the refrigerant circuit in the first disposition state is provided with the spring to drive the needle seated in the valve seat in the direction of advance of the needle when the valve is completely closed, and when The force that pushes the needle in the direction of backward movement of the needle due to the difference in opening pressure of the back pressure valve exceeds the force of impulse in the direction of advance of the needle, the needle is released from its seat in the valve seat This produces a configuration in which the refrigerant in the part of the refrigerant circuit between the first expansion valve, the second expansion valve, and the gas purge valve that includes the tank can be passed to the outdoor heat exchanger, the indoor heat exchanger and / or the compressor when there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit between the expansion valve, the second expansion valve, and the gas purge valve that includes the reservoir.

Therefore, in the refrigerant circuit of this air conditioner, configured by connecting the compressor, the outdoor heat exchanger, the first expansion valve, the tank, the second expansion valve, the indoor heat exchanger, and the gas purge valve, liquid stagnation in the reservoir can be avoided without providing a liquid stagnation prevention tube, despite using full shut-off expansion valves such as the first expansion valve, the second expansion valve and the gas purge valve.

An air conditioner according to an eighth aspect is the air conditioner according to any of the fifth to seventh aspects, wherein the force of the spring when the valve is completely closed is adjusted such that the total sum of the difference in the opening pressure of the back pressure valve and a maximum saturation pressure is equal to or less than the test pressure of the tank, where the maximum saturation pressure is the saturation pressure of the refrigerant corresponding to the maximum value of atmospheric temperature at the location where the tank, the first expansion valve, the opening / closing valve and the gas purge valve are installed.

Therefore, the impulse force of the spring when the valve is completely closed is adjusted in the present patent so that the total sum of the difference in the opening pressure of the back pressure valve and the maximum saturation pressure is equal to or less than the test pressure of the tank, where the maximum saturation pressure is the saturation pressure of the refrigerant corresponding to the maximum value of the atmospheric temperature at the location where the first expansion valve is installed, the opening / closing valve, and the gas purge valve, as described above. Even assuming conditions of an atmospheric temperature so high that the refrigerant in the part of the refrigerant circuit between the first expansion valve, the opening / closing valve and the gas purge valve that includes the tank increases in pressure up to the pressure of maximum saturation, the force generated by the opening pressure difference of the back pressure valve to push the needle in the direction of needle retraction will thereby exceed the force of the spring in the direction of advance of the needle before the test pressure of the reservoir is exceeded, and the needle can be released from its seat in the valve seat. Therefore, the refrigerant in the part of the refrigerant circuit between the first expansion valve, the opening / closing valve, and the gas purge valve that includes the reservoir can be passed to the outdoor heat exchanger, the exchanger of heat

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indoor, and / or the compressor before the test pressure of the tank is exceeded, and liquid stagnation in the tank can be avoided.

Therefore, in this air conditioner, the stagnation of liquid in the tank can be properly avoided while taking into account the test pressure of the tank.

An air conditioner according to a ninth aspect is the air conditioner according to the fourth or eighth aspect, where the test pressure of the reservoir is a pressure value obtained by multiplying the nominal pressure of the reservoir by a factor of security.

Because the test pressure in the present patent is obtained based on the nominal pressure of the reservoir, it is possible to properly adjust the opening pressure difference of the back pressure valve, of the first expansion valve, the second valve of expansion, and / or the gas purge valve in the first disposition state, that is to say, properly adjust the impulse force of the spring when the valve is completely closed.

An air conditioner according to a tenth aspect is the air conditioner according to the first or fifth aspect, wherein the opening / closing valves are a second expansion valve and a liquid side shut-off valve connected between the second expansion valve and the indoor heat exchanger, and the second expansion valve is a full closing expansion valve that is completely closed by a needle that sits in a valve seat. The second expansion valve in the present patent is provided in the refrigerant circuit in a second state of arrangement in which the refrigerant from the reservoir flows inward from the backward direction side of the valve seat needle, and towards out towards the forward direction side of the valve seat through a gap between the needle and the valve seat. The second expansion valve provided in the refrigerant circuit in the second state of arrangement has a spring to drive the needle seated in the valve seat in the direction of advance of the needle when the valve is completely closed, where the second valve of Expansion is configured so that the needle is released from its seat in the valve seat when the impulse force of the spring in the forward direction of the needle is exceeded by a force that pushes the needle in the reverse direction of the needle as generated by a difference in the opening pressure of the back pressure valve, which is the difference between the pressure of the refrigerant in a space on the backward direction side of the needle of the valve seat and the pressure of the refrigerant in a space on the side of the forward direction of the valve seat needle.

When a full shut-off expansion valve is used as the second expansion valve and both the liquid side shut-off valve and the second expansion valve become completely closed due to a setback such as an erroneous operation of the flow valve. liquid side closure and / or the second expansion valve, there is a risk of liquid stagnation occurring in the part of the refrigerant circuit between the liquid side closing valve and the second expansion valve. Specifically, there is a risk that the part of the refrigerant circuit between the liquid side shut-off valve and the second expansion valve will be filled with liquid refrigerant, the liquid refrigerant will be sealed inside this part, and an increase in temperature will cause that the liquid side shut-off valve, the second expansion valve, and / or other equipment that configures this part, suffer a breakage or the like. When there is an increase in the refrigerant pressure in the part of the refrigerant circuit between the liquid side shut-off valve and the second expansion valve, the refrigerant in the part of the refrigerant circuit between the liquid side shut-off valve and the The second expansion valve must be able to be passed to the rest of the refrigerant circuit to avoid the liquid stagnation in the part between the liquid side shut-off valve and the second expansion valve.

In view of this, in addition to preventing liquid stagnation in the tank by providing the first expansion valve (the first expansion valve and / or the gas purge valve when there is also a gas purge valve) in the refrigerant circuit In the first disposition state as described above, the second expansion valve is provided in the refrigerant circuit in the second disposition state, in which the coolant in the reservoir flows inward from the direction side of retracting the needle from the valve seat, and outward toward the forward direction side of the needle of the valve seat through the gap between the needle and the valve seat. A force will act in this way to push the needle in the direction of backward movement of the needle when the difference in the opening pressure of the back pressure valve takes place, which is the difference between the pressure of the refrigerant in the space on the side of the backward direction of the valve seat needle and the refrigerant pressure in the space on the side of the forward direction of the valve seat needle when the second expansion valve is completely closed. The force that pushes the needle in the reverse direction of the needle due to this pressure difference of the back pressure valve is used to provide a configuration in which the second expansion valve provided in the refrigerant circuit in the second state The arrangement is provided with a spring to propel the needle seated in the valve seat in the direction of advance of the needle when the valve is completely closed, and when the force that pushes the needle in the direction of retraction of the needle due to the difference in the opening pressure of the back pressure valve exceeds the impulse force

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of the spring in the direction of advance of the needle, the needle is released from its seat in the valve seat. Therefore, a configuration can be achieved in which the refrigerant in the part of the refrigerant circuit between the liquid side shut-off valve and the second expansion valve can be passed to the reservoir when there is an increase in the refrigerant pressure in the part of the refrigerant circuit between the liquid side shut-off valve and the second expansion valve.

Therefore, in the refrigerant circuit of this air conditioner, configured by connecting the compressor, the outdoor heat exchanger, the first expansion valve, the reservoir, the second expansion valve, the liquid side shut-off valve, and the indoor heat exchanger (including the gas purge valve when there is also a gas purge valve), liquid stagnation in the tank can be avoided without providing a liquid stagnation prevention tube, and the liquid stalling can be avoided. liquid stagnation between the liquid side shut-off valve and the second expansion valve.

An air conditioner according to an eleventh aspect is the air conditioner according to the tenth aspect, wherein the impulse force of the spring of the second expansion valve when the valve is completely closed is adjusted so that the total sum of a maximum saturation pressure and the difference in the opening pressure of the back pressure valve of the second expansion valve is equal to or less than the minimum value of the test pressures of the components that constitute the part of the refrigerant circuit from the second expansion valve to the liquid side shut-off valve, where the maximum saturation pressure is the saturation pressure of the refrigerant that corresponds to the maximum value of the atmospheric temperature at the location where the second expansion valve and The liquid side shut-off valve is installed.

The impulse force of the spring when the valve is completely closed is adjusted in the present patent so that the total sum of the opening pressure difference of the back pressure valve and the maximum saturation pressure is equal to or less than the value minimum of the test pressures of the components that constitute the refrigerant circuit part of the second expansion valve to the liquid side shut-off valve, where the maximum saturation pressure is the saturation pressure of the refrigerant corresponding to the maximum value of the atmospheric temperature at the location where the second expansion valve is installed, as described above. Even assuming conditions of an atmospheric temperature so high that the refrigerant in the part of the refrigerant circuit between the liquid side shut-off valve and the second expansion valve increases the pressure to the maximum saturation pressure, the force generated by the difference The opening pressure of the backpressure valve to push the needle in the direction of needle retraction will thus exceed the force of the spring in the direction of advance of the needle before the test pressures of the needle are exceeded. components that constitute the part of the refrigerant circuit from the second expansion valve to the liquid side shut-off valve, and the needle can be released from its seat in the valve seat. Therefore, the refrigerant in the part of the refrigerant circuit between the liquid side shut-off valve and the second expansion valve can be passed into the reservoir before the test pressures of the components constituting the part of the liquid are exceeded. refrigerant circuit from the second expansion valve to the liquid side shut-off valve, and liquid stagnation between the liquid side shut-off valve and the second expansion valve can be avoided. There is a risk in the present patent that the refrigerant that is allowed to pass into the tank causes an increase in the pressure in the tank, but because the first expansion valve (and the first expansion valve and / or the valve of gas purge when there is also a gas purge valve), it is provided in the first state of disposal, the refrigerant will be allowed to pass to the outdoor heat exchanger (to the outdoor heat exchanger and / or the compressor when there is also a gas purge valve), before the tank test pressure is exceeded.

Therefore, in addition to preventing liquid stagnation in the reservoir without providing a liquid stagnation prevention tube in this air conditioner, liquid stagnation between the liquid side shut-off valve and the liquid can be adequately avoided. second expansion valve while taking into account the test pressures of the components that constitute the part of the refrigerant circuit from the second expansion valve to the liquid side shut-off valve.

An air conditioner according to a twelfth aspect is the air conditioner according to the eleventh aspect, wherein the test pressures of the components constituting the part of the refrigerant circuit from the second expansion valve to the expansion valve Liquid side closing are pressure values obtained by multiplying the nominal pressures of the components that constitute the part of the refrigerant circuit from the second expansion valve to the liquid side closing valve by a safety factor.

Because the test pressures in the present patent are obtained based on the nominal pressures of the components of the refrigerant circuit from the second expansion valve to the liquid side shut-off valve, it is possible to properly adjust the difference in opening pressure of the back pressure valve

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the second expansion valve provided in the second disposition state, that is to say, properly adjust the impulse force of the spring when the valve is completely closed.

Brief description of the drawings

FIG. 1 is a drawing of a schematic configuration of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a drawing showing the area around a first expansion valve, a reservoir, a second expansion valve and a liquid side shut-off valve.

FIG. 3 is a schematic cross-sectional view of the expansion valve.

FIG. 4 is a cross-sectional view showing an area around a needle of the expansion valve when the expansion valve is completely closed (with the opening of the back pressure valve inactive).

FIG. 5 is a schematic cross-sectional view showing the proximity of the expansion valve needle when the expansion valve is completely closed (with the opening of the back pressure valve active).

FIG. 6 is a drawing showing the area around the first expansion valve, a reservoir, a second expansion valve, and a liquid side shut-off valve in accordance with Modification 1.

FIG. 7 is a drawing showing a close area of a first expansion valve, a reservoir, a second expansion valve, and a liquid side shut-off valve, in accordance with Modification 1.

FIG. 8 is a drawing of a diagram of a configuration of an air conditioner according to Modification 2.

FIG. 9 is a drawing of a diagram of a configuration of an air conditioner according to Modification 3.

FIG. 10 is a drawing showing the near area of a first expansion valve, a reservoir, a

second expansion valve, and a liquid side shut-off valve in accordance with Modification 3.

FIG. 11 is a drawing showing the near area of a first expansion valve, a reservoir, a

second expansion valve, and a liquid side shut-off valve in accordance with Modification 3.

FIG. 12 is a drawing showing the near area of a first expansion valve, a reservoir, a

second expansion valve, and a liquid side shut-off valve in accordance with Modification 3.

FIG. 13 is a drawing showing the near area of a first expansion valve, a reservoir, a

second expansion valve, and a liquid side shut-off valve in accordance with Modification 3.

FIG. 14 is a drawing showing the near area of a first expansion valve, a reservoir, a

second expansion valve and a liquid side shut-off valve in accordance with Modification 3.

FIG. 15 is a drawing showing the near area of a first expansion valve, a reservoir, a

second expansion valve, and a liquid side shut-off valve in accordance with Modification 3.

FIG. 16 is a drawing showing the near area of a first expansion valve, a reservoir, a

second expansion valve, and a liquid side shut-off valve in accordance with Modification 3.

FIG. 17 is a drawing of a schematic of a configuration of an air conditioner according to Modification 5.

FIG. 18 is a drawing of a schematic of a configuration of the air conditioner according to Modification 5.

FIG. 19 is a drawing showing the near area of a first expansion valve, a reservoir, and a liquid side shut-off valve in accordance with Modification 5.

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FIG. 20 is a drawing showing the near area of a first expansion valve, a reservoir, and a liquid side shut-off valve in accordance with Modification 5.

FIG. 21 is a drawing showing the near area of a first expansion valve, a reservoir, and a liquid side shut-off valve in accordance with Modification 5.

FIG. 22 is a drawing showing the near area of a first expansion valve, a reservoir, and a liquid side shut-off valve in accordance with Modification 5.

Description of the realizations

An embodiment and modifications of an air conditioner according to the present invention are described below with reference to the drawings. The specific configuration of the air conditioner according to the present invention is not limited to the following embodiment or modifications thereof, and may be modified within the scope of the claims.

(1) Configuration of an air conditioner

FIG. 1 is a drawing of a diagram of a configuration of an air conditioner 1 according to an embodiment of the present invention.

The air conditioner 1 is an apparatus capable of cooling or heating the interior of a room in a building or the like by performing an operation of a steam compression refrigeration cycle. The air conditioner 1 is configured by mainly connecting an outdoor unit 2 and an indoor unit 4. The outdoor unit 2 and the indoor unit 4 in the present patent are connected through a coolant communication tube 5 and a refrigerant gas communication tube 6. Specifically, a refrigerant circuit 10 by vapor compression of the air conditioner 1 is configured by connecting the outdoor unit 2 and the indoor unit 4 through the refrigerant communication tubes 5, 6. Various refrigerants can be used as the sealed refrigerant in the refrigerant circuit 10, but in this case it is R32, a type of HFC refrigerant that is sealed inside as refrigerant.

<Indoor units>

The indoor unit 4, which is installed in a room, configures part of the refrigerant circuit 10. The indoor unit 4 mainly has an indoor heat exchanger 41.

The indoor heat exchanger 41 is a heat exchanger that functions as a refrigerant evaporator and cools the indoor air during an air cooling operation, and functions as a refrigerant heat radiator and heats the indoor air during a heating operation The liquid side of the indoor heat exchanger 41 is connected to the coolant communication tube 5, and the gas side of the indoor heat exchanger 41 is connected to the coolant gas communication tube 6.

The indoor unit 4 has an indoor fan 42 to extract air from the interior into the interior of the indoor unit 4 and return the air in the room as supplied air after said air has exchanged heat with the refrigerant in the heat exchanger. 41 indoor heat. The indoor fan 42 is driven by a motor 43 of the indoor fan.

The indoor unit 4 has a controller 44 on the indoor side to control the actions of the components that constitute the indoor unit 4. The controller 44 on the indoor side has a microcomputer, a memory, and / or the like provided to control the indoor unit 4, and the controller is designed to be able to exchange control signals and the like with a remote controller (not shown), and exchange control signals and the like with the outdoor unit 2 through a transmission line 8a.

<Outdoor unit>

The outdoor unit 2, which is installed outside the room, configures part of the refrigerant circuit 10. The outdoor unit 2 mainly has a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23 , a first expansion valve 24, a reservoir 25, a second expansion valve 26 (an opening / closing valve), a closing valve 27 on the liquid side, and a closing valve 28 on the gas side.

The compressor 21 is a mechanism for compressing low pressure refrigerant in the refrigeration cycle to high pressure. The compressor 21 has a hermetic structure in which a compression element by

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Rotary displacement, "scroll" (or spiral), or other (not shown) is rotatably driven by a compressor motor 21a controlled by an inverter. An intake tube 31 is connected to the intake side of the compressor 21, and a discharge tube 32 is connected to the discharge side. The intake tube 31 is a refrigerant tube that connects to the intake side of the compressor 21 and a first socket 22a of the switching valve

22 four way. An accumulator 29 is provided in the intake tube 31. The discharge tube 32 is a refrigerant tube that connects the discharge side of the compressor 21 and a second socket 22b of the four-way switching valve 22. A non-return valve 32a is provided in the discharge tube 32.

The four-way switching valve 22 is a mechanism for switching the direction of the refrigerant flow in the refrigerant circuit 10. During the air cooling operation, the four-way switching valve 22 performs a switching that causes the heat exchanger Outdoor heat 23 functions as a compressor refrigerant heat radiator in compressor 21, and causes the indoor heat exchanger 41 to function as an evaporator of the refrigerant that has radiated heat in the outdoor heat exchanger 23, and from that mode changes to the state of the air cooling cycle. Specifically, during the air cooling operation, the four-way switching valve 22 performs a switching that interconnects the second socket 22b and a third socket 22c, and interconnects the first socket 22a and a fourth socket 22d. The discharge side of the compressor 21 (the discharge tube 32 in the present patent) and the gas side of the outdoor heat exchanger 23 (a first refrigerant gas tube 33 in the present patent), are thus connected ( see the continuous lines of the four-way switching valve 22 in FIG. 1). Furthermore, the intake side of the compressor 21 (the intake tube 31 in the present patent) and the side of the refrigerant gas communication tube 6 (a second refrigerant gas tube 34 in the present patent) are connected (see the continuous lines of the four-way switching valve 22 in FIG. 1). During the air heating operation, the four-way switching valve 22 performs a switching that causes the outdoor heat exchanger 23 to function as an evaporator of the refrigerant that has radiated heat in the indoor heat exchanger 41, and causes that the indoor heat exchanger 41 functions as a refrigerant heat radiator that has been compressed in the compressor 21, and thus changes to a state of an air heating cycle. Specifically, during the air heating operation, the four-way switching valve 22 performs a switching that interconnects the second socket 22b and the fourth socket 22d, and interconnects the first socket 22a and the third socket 22c. The discharge side of the compressor 21 (the discharge tube 32 in the present patent) and the side of the refrigerant gas communication tube 6 (the second refrigerant gas tube 34 in the present patent), are connected in this way (see the broken lines of the four-way switching valve 22 in FIG. 1). Furthermore, the intake side of the compressor 21 (the intake tube 31 in this patent) and the gas side of the outdoor heat exchanger 23 (the first refrigerant gas tube 33 in the present patent) are connected (see the broken lines of the four-way switching valve 22 in FIG. 1). The first refrigerant gas tube 33 is a refrigerant tube that connects the third socket 22c of the four-way switching valve 22 and the gas side of the outdoor heat exchanger 23. The second refrigerant gas tube 34 is a refrigerant tube that connects the fourth socket 22d of the four-way switching valve 22 and the side of the refrigerant gas communication tube 6.

The outdoor heat exchanger 23 is a heat exchanger that functions as a refrigerant heat radiator that uses outside air as a cooling source during the air cooling operation, and functions as a refrigerant evaporator that uses air from the outside as a heating source during the air heating operation. The liquid side of the outdoor heat exchanger 23 is connected to a coolant tube 35, and the gas side is connected to the first coolant tube 33. The coolant tube 35 is a coolant tube that connects the liquid side of the heat exchanger

23 outside and the side of the coolant communication tube 5.

During the air cooling operation, the first expansion valve 24 depressurizes high pressure refrigerant in the refrigeration cycle to an intermediate pressure in the refrigeration cycle, after the refrigerant has radiated heat in the outdoor heat exchanger 23 . During the air heating operation, the first expansion valve 24 depressurizes intermediate pressure refrigerant in the refrigeration cycle, which has accumulated in the tank 25, to a low pressure in the refrigeration cycle. The first expansion valve 24 is provided in a part of the coolant tube 35 that is located between the outdoor heat exchanger 23 and the reservoir 25. The part of the coolant tube 35 that connects the heat exchanger 23 of outside and the first expansion valve 24 in the present patent is a first coolant tube 35a, and the part of the coolant tube 35 that connects the first expansion valve 24 and the reservoir 25 is a second coolant tube 35b . An electric expansion valve is used in the present patent as the first expansion valve 24. The detailed structure of the first expansion valve 24 will be described below.

The tank 25 is provided between the first expansion valve 24 and the second expansion valve 26. The tank 25 is a container capable of accumulating intermediate pressure refrigerant in the refrigeration cycle during the air cooling operation and the operation of air heating

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During the air cooling operation, the second expansion valve 26 (an open / close valve) depressurizes intermediate pressure refrigerant in the refrigeration cycle accumulated in the tank 25 at a low pressure in the refrigeration cycle. During the air heating operation, the second expansion valve 26 depressurizes high pressure refrigerant in the refrigeration cycle at an intermediate pressure in the refrigeration cycle after the refrigerant has radiated heat in the indoor heat exchanger 41. The second expansion valve 26 is provided in a part of the coolant tube 35 that is located between the reservoir 25 and the closing valve 27 on the liquid side. The part of the coolant tube 35 that connects the reservoir 25 and the second expansion valve 26 is a third coolant tube 35c, and the part of the coolant tube 35 that connects the second expansion valve 26 and the valve closure 27 of the liquid side is a fourth tube 35d of coolant. In the present patent an electric expansion valve is used as the second expansion valve 26. The detailed structure of the second expansion valve 26 will be described below.

The shut-off valve 27 on the liquid side (an open / close valve) and the shut-off valve 28 on the gas side are valves provided in sockets connected to external devices or conduits (specifically, the coolant communication tube 5 and the refrigerant gas communication tube 6). The shut-off valve 27 on the liquid side is provided in a final part of the coolant tube 35 (more specifically, the fourth coolant tube 35d). The shut-off valve 28 on the gas side is provided in an end portion of the second refrigerant gas tube 34.

The outdoor unit 2 has an outdoor fan 36 for extracting air from the outside into the interior of the outdoor unit 2 and expelling the air outward after said air has exchanged heat with the refrigerant in the heat exchanger 23 outside. The outdoor fan 36 is driven by a motor 37 of the outdoor fan.

The outdoor unit 2 has a controller 38 on the outdoor side to control the actions of the components that constitute the outdoor unit 2. The controller 38 on the outdoor side, which has a microcomputer, a memory, and / or the like provided To control the outdoor unit 2, it is designed to be able to exchange control signals and the like with the indoor unit 4 through a transmission line 8a.

<Refrigerant communication tubes>

The refrigerant communication tubes 5, 6, which are mechanized refrigerant tubes in situ when the air conditioner 1 is installed in a building or other location of the installation, have different lengths according to the installation location and / or installation conditions such as the combination of the outdoor unit and the indoor unit.

As described above, the refrigerant circuit 10 of the air conditioner 1 is configured from the connection between the outdoor unit 2, the indoor unit 4, and the refrigerant communication tubes 5, 6. The air conditioner 1 is designed so that changing the four-way switching valve 22 to the state of the air cooling cycle causes the air cooling operation, in which the refrigerant is circulated sequentially through of the compressor 21, the outdoor heat exchanger 23, the first expansion valve 24, the tank 25, the second expansion valve 26 (an opening / closing valve), the closing valve 27 on the liquid side (a valve opening / closing) and indoor heat exchanger 41. The air conditioner 1 is also designed so that changing the four-way switching valve 22 to the state of the air heating cycle causes the air heating operation to be carried out, in which refrigerant is circulated sequentially through of the compressor 21, the indoor heat exchanger 41, the shut-off valve 27 on the liquid side (an open / close valve), the second expansion valve 26 (an open / close valve), the reservoir 25, the first expansion valve 24, and outdoor heat exchanger 23. The configuration in the present patent may change between the air cooling operation and the air heating operation, but another option is a configuration that does not have a four-way switching valve and can only perform an air cooling operation. or only an air heating operation.

<Controllers>

The air conditioner 1 is designed so that the various devices of the outdoor unit 2 and the indoor unit 4 can be controlled by a controller 8, configured from the controller 44 on the indoor side and the controller 38 from the outer side. Specifically, the controller 8 is configured to control the operations of the entire air conditioner 1, including the air cooling operation, the air heating operation, and / or the like, described above, through the transmission line 8a connecting the controller 44 on the indoor side and the controller 38 on the outdoor side.

(2) Basic actions of the air conditioner

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The basic actions of the air conditioner 1 are described below using FIG. 1. The air conditioner 1 can perform an air cooling operation and an air heating operation as basic operations.

<Air heating operation>

During the air heating operation, the four-way switching valve 22 is changed to the state of the air heating cycle (the state shown by the broken lines in FIG. 1).

In the refrigerant circuit 10, low pressure refrigerant gas is extracted in the refrigeration cycle into the compressor 21 and discharged after being compressed to a high pressure.

The high-pressure refrigerant gas discharged from the compressor 21 is sent through the four-way switching valve 22, the gas side shut-off valve 28, and the refrigerant gas communication tube 6 to the heat exchanger 41 of inside.

The high-pressure refrigerant gas sent to the indoor heat exchanger 41 is subjected to heat exchange with the indoor air supplied as a source of cooling by the indoor fan 42 and radiates heat in the indoor heat exchanger 41, becoming in high pressure coolant. The indoor air is heated in this way and then supplied to the interior of the room, whereby the heating of the air inside the room is carried out.

The high-pressure coolant that has radiated heat in the indoor heat exchanger 41 is sent through the coolant communication tube 5 and the shut-off valve 27 on the liquid side to the second expansion valve 26.

The high pressure coolant sent to the second expansion valve 26 is depressurized to an intermediate pressure in the refrigeration cycle by the second expansion valve 26, becoming a biphasic gas-liquid, intermediate pressure refrigerant.

The biphasic gas-liquid refrigerant, at intermediate pressure depressurized by the second expansion valve 26, temporarily accumulates in the tank 25, and is then sent to the first expansion valve 24.

The biphasic gas-liquid refrigerant, at intermediate pressure sent to the first expansion valve 24 is depressurized at a low pressure in the refrigeration cycle by the first expansion valve 24, becoming a low-pressure refrigerant, biphasic gas-liquid.

The two-phase gas-liquid, low pressure refrigerant depressurized by the first expansion valve 24 is sent to the outdoor heat exchanger 23.

The two-phase low-pressure gas-liquid refrigerant sent to the outdoor heat exchanger 23 is subjected to heat exchange with outside air supplied as a heat source by the outdoor fan 36 and evaporated in the outdoor heat exchanger 23 , becoming low pressure refrigerant gas.

The low-pressure refrigerant evaporated in the outdoor heat exchanger 23 is extracted through the four-way switching valve 22 into the compressor 21.

<Air cooling operation>

During the air cooling operation, the four-way switching valve 22 is changed to the state of the air cooling cycle (the state shown with the continuous lines in FIG. 1).

In the refrigerant circuit 10, the low pressure refrigerant gas in the refrigeration cycle is drawn into the compressor 21 and discharged after being compressed at a high pressure in the refrigeration cycle.

The high pressure refrigerant gas discharged from the compressor 21 is sent through the four-way switching valve 22 to the outdoor heat exchanger 23.

The high pressure refrigerant gas sent to the outdoor heat exchanger 23 is subjected to heat exchange with the outside air supplied as a cooling source by the outdoor fan 36 and radiates heat in the outdoor heat exchanger 23, becoming in high pressure coolant.

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The high pressure coolant that has radiated heat in the outdoor heat exchanger 23 is sent to the first expansion valve 24.

The high pressure coolant sent to the first expansion valve 24 is depressurized at an intermediate pressure in the refrigeration cycle by the first expansion valve 24, becoming a biphasic gas-liquid intermediate pressure refrigerant.

The biphasic gas-liquid refrigerant, at depressurized intermediate pressure in the first expansion valve 24 is temporarily accumulated in the tank 25 and then sent to the second expansion valve 26.

The biphasic gas-liquid refrigerant, at intermediate pressure sent to the second expansion valve 26 is depressurized at a low pressure in the refrigeration cycle by the second expansion valve 26, becoming biphasic gas-liquid refrigerant, at low pressure.

The biphasic gas-liquid, intermediate pressure depressurized refrigerant by the second expansion valve 26 is sent through the liquid side shut-off valve 27 and the refrigerant liquid communication tube 5 to the indoor heat exchanger 41.

The two-phase low-pressure gas-liquid refrigerant sent to the indoor heat exchanger 41 is subjected to heat exchange with the indoor air supplied as a source of heat by the indoor fan 42 and evaporates in the heat exchanger 41 indoor. The indoor air is cooled in this way and then supplied to the interior of the room, whereby the cooling of the air inside the room is carried out.

The low pressure refrigerant gas evaporated in the indoor heat exchanger 41 is extracted through the refrigerant gas communication tube 6, the gas side shut-off valve 28, and the four-way switching valve 22, back inside the compressor 21.

(3) Detailed structure and actions of expansion valves

<Basic structures of expansion valves>

In the air conditioner 1, when "grooved" needle type expansion valves are used as the first expansion valve and the second expansion valve 26 provided on the upstream and downstream sides of the reservoir 25, there is a risk of liquid reflux, in which the refrigerant returns to the compressor 21, at the beginning of the air cooling operation and / or the air heating operation. A conceivable countermeasure is to use full-closing expansion valves, in which no grooves are formed in the needles and the valves are completely closed by the needles that are seated in the valve seats, such as the first expansion valve 24 and the second expansion valve 26.

First, a description of the basic structures and actions of the first expansion valve 24 and the second expansion valve 26 composed of full-closing expansion valves is provided.

Each of the first expansion valve 24 and the second expansion valve 26 mainly have a valve body 51, a needle 61, and a housing 71, as shown in FIG. 3. In the example described in the present patent, the first expansion valve 24 and the second expansion valve 26 are both arranged so that the needle 61 moves vertically, but this feature does not imply a limitation for the valves to be arranged so that the needle 61 moves horizontally or in another direction. Furthermore, in the present patent, when the needle 61 is seated in a valve seat 55, the direction in which the needle 61 moves (down) is the direction of advance of the needle, and when the needle 61 retracts from the valve seat 55, the direction in which the needle 61 travels (upwards) is the direction of backward movement of the needle.

The valve body 51 in the present patent is a substantially tubular element that extends vertically (ie, in the direction in which the needle 61 travels), in which a chamber 52 of the valve is formed. The valve chamber 52 has an upper chamber 52a of the large diameter valve, and a lower chamber 52b of the small diameter valve and which is located under the upper chamber 52a of the valve. Also formed in the valve body 51 are a first coolant outlet 53 that empties into the side of the chamber 52 of the valve (the upper chamber 52a of the valve in the present patent), and a second coolant outlet 54 which flows into the lower part of the valve chamber 52 (the lower chamber 52b of the valve in the present patent). The valve seat 55 is also provided in the valve body 51. Specifically, the valve seat 55 is provided in the valve body 51 to divide the upper chamber 52a of the valve and the lower chamber 52b of the valve. The upper chamber 52a of the valve thereby configures a space on the backward direction side of the needle of the valve seat 55 (the upper space in the present patent), and the lower chamber 52b of the valve configures a space on the side of the forward direction of the needle of the valve seat 55 (the lower space in the present patent). Of the two shots 53,

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54 of refrigerant, and the second coolant outlet 54 is provided on the forward direction side of the needle of the valve seat 55. A hole 55a, open to interconnect the upper chamber 52a of the valve and the lower chamber 52b of the valve in the direction in which the needle 61 travels (vertically in the present patent), is formed in the valve seat 55. A tubular element 56 shaped as a female thread is secured by pressure adjustment or the like on the inner peripheral surface of the valve body 51. The upper part of the element 56 formed as a female thread protrudes above the valve body 51 , and female thread 56a is formed on the inner peripheral surface. A substantially tubular needle guide 57 is secured by pressure adjustment or the like in the lower part of the element 56 formed as a female thread.

The needle 61 in the present patent is an element that advances vertically (that is, in the direction in which the needle travels) and retracts from the valve seat 55, and is inserted into the inner peripheral side of the guide 57 needle to move vertically. The needle 61 is associated by a spring 62 and a spring receiving element 63, described below, to an axis 64 of the valve disposed above the needle 61. The axis 64 of the valve is a substantially shaped element of rod that extends vertically (that is, in the direction in which the needle travels) from the valve body 51 through the case 71. The lower end of the valve shaft 64 is inserted into the peripheral side of the needle guide 57 to be able to rotate and move vertically (that is, in the direction in which the needle moves). A male thread 64a that engages with the female thread 56a of the element 56 formed as a female thread, is formed on the outer peripheral surface of the central part vertically (i.e., in the direction in which the needle travels) of the axis 64 from valvule. A substantially tubular rotor 81 composed of a permanent magnet is secured through a bushing 65 to the upper side of the male thread 64a of the valve shaft 64.

The case 71 in the present patent is a substantially tubular element whose upper end is closed. The case 71 is secured to the upper end of the valve body 51 by means of a metal fastener or the like (not shown). A substantially tubular sleeve 72 extending towards the bottom is provided on the inner surface of the upper end of the case 71. The upper end of the valve shaft 64 is inserted into the inner peripheral side of the sleeve 72 in order to rotate and move vertically (that is, in the direction in which the needle moves). The outer peripheral surface of the rotor 81 is facing the inner peripheral surface of the case 71 with a slight gap in the middle. A stator 82 composed of an electromagnet is provided in a position facing the rotor 81 on the outer peripheral side of the box 71.

With such a configuration, when electric current is directed to the stator 82, the stator 82 and the rotor 81 function as a stepper motor, and the rotor 81 rotates according to the amount of current conduction (pulse value) . When the rotor 81 rotates, the valve shaft 64, which rotates integral with the rotor 81, also rotates. When the valve shaft 64 rotates, because the male thread 64a of the valve shaft 64 engages with the female thread 56a of the element 56 formed as a female thread, the valve shaft 64 is screwed into the valve body 51, and the axis 64 of the valve thus moves vertically (that is, in the direction in which the needle moves). When the axis 64 of the valve travels vertically (i.e. in the direction in which the needle moves), the needle 61 associated with the axis 64 of the valve also moves vertically (i.e. in the direction in which the needle moves). The size of the gap between the needle 61 and the valve seat 55 can be adjusted in this way, and the refrigerant flow rate through the first expansion valve 24 and / or the second expansion valve 26 can be controlled while depressurizing the refrigerant. Therefore, the gap between the needle 61 and the valve seat 55 disappears when the needle 61 is seated in the valve seat 55 because the valve shaft 64 is screwed into the valve body 51, and the first expansion valve 24 and / or the second expansion valve 26 is completely closed (see FIG. 3).

<Structure to prevent liquid stagnation in the tank>

However, when full shut-off expansion valves such as the first expansion valve 24 and the second expansion valve 26 (opening / closing valves) are used, there is a risk of liquid stagnation in the reservoir 25 when the two valves of expansion 24, 26 close completely. Therefore, when full shut-off expansion valves such as the first and second expansion valves 24, 26 are used to allow to avoid liquid stagnation in the tank 25 without providing a liquid stagnation prevention tube even when the two expansion valves 24, 26 close completely, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 which includes the tank must be able to be passed to the rest of the refrigerant circuit 10 when there is an increase in the refrigerant pressure in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 that includes the tank 25.

In view of this, the first expansion valve 24 is provided in the refrigerant circuit 10 in a first disposition state, in which refrigerant flows into the reservoir 25 from the direction of advance of the seat needle 55, and outward towards the reverse direction of the needle of the valve seat 55 (the upper side of the valve seat 55 in the present patent) (see FIGS. 2 and 3). Specifically, the first coolant tube 35a for connecting with the heat exchanger 23 of

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outside, it is connected to the first outlet 53 of the first expansion valve 24, and the second coolant tube 35b for connecting to the tank 25 is connected to the second coolant outlet 54 of the first expansion valve 24, such as It is shown in FIGS. 2 and 3. When the first expansion valve 24 provided in the refrigerant circuit 10 in the first disposition state is completely closed, these connections generate a pressure difference between the pressure of the refrigerant P1 in the space on the steering side of recoil of the needle of the valve seat 55 (the upper chamber 52a of the valve in the present patent), and the pressure of the refrigerant P2 in the space on the side of the forward direction of the needle of the valve seat 55 ( the lower chamber 52b of the valve in the present patent), where this pressure difference is indicated as the opening pressure difference of the AP back pressure valve (= P2-P1). This pressure difference generates a thrust force Fu (an upward thrust force in the present patent), which is exerted on the needle 61 in the direction of needle retraction (see FIG. 4). The force Fu that pushes the needle 61 in the direction of retraction of the needle due to this pressure difference of opening of the back pressure valve AP is used to provide a configuration in which the first expansion valve 24 provided in the refrigerant circuit 10 in the first state of arrangement is provided with a spring 62 to drive the needle 61 seated in the valve seat 55 in the direction of advance of the needle (downwards, in the present patent), when the valve is completely closed , and when the force Fu that pushes the needle 61 in the direction of retraction of the needle due to the difference in opening pressure of the back pressure valve AP, exceeds the out of impulse Fd of the spring 62 in the direction of advance of the needle, the needle 61 is released from its seat in the valve seat 55 (see FIGS. 4 and 5). Specifically, the spring receiving element 63 is associated with the lower end of the valve shaft 64 to move in a solidary manner in the direction in which the needle 61 travels (vertically in the present patent), and the spring receiving element 63 and the needle 61 are vertically associated by the spring 62, as shown in FIGS. 3 to 5. A helical spring capable of expanding and contracting in the direction in which the needle 61 moves is used in the present patent as the spring 62. This produces a configuration in which the needle 61 moves vertically due to the displacement vertical axis 64 of the valve, while the vertical distance between the axis 64 of the valve and the needle 61 can expand and contract elastically. When the lower end of the valve shaft 64 reaches the lowest position in the travel range while the valve is completely closed in FIG. 4, the needle 61 becomes seated in the valve seat 55, while the spring 62 contracts to less than its free length, but could still contract more (this state is referred to below as the "inactive opening state of the valve"). back pressure ”). The spring 62 thus generates a force Fd that drives the needle 61 seated in the valve seat 55 in the forward direction of the needle, and the needle 61 is pushed against the valve seat 55 by the pulse force Fd of the spring 62. When the force Fu generated by the difference in opening pressure of the AP backpressure valve to push the needle 61 in the direction of needle retraction exceeds the impulse force Fd of the needle 61 in the direction of advance of the needle while the valve is completely closed, the axis 64 of the needle does not move in the direction of backward movement of the needle (upwards in the present patent), the needle 61 is separated from the valve seat 55 in the direction of retraction of the needle (upwards in the present patent), while the spring 62 contracts even more in the inactive opening state of the back pressure valve, and the needle 61 is released from its seat in the valve seat 55 ( This state is referred to below as the "active opening state of the back pressure valve"), as shown in FIG. 5. At this time, the length of the spring 62 contracts from the length LO in the inactive opening state of the back pressure valve to the length L in the active opening state of the back pressure valve. When there is an increase in the refrigerant pressure (equivalent to the pressure P2) in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 which includes the tank 25, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 which includes the tank 25 can thus be passed to the outdoor heat exchanger 23 (see the arrow indicating the flow of the refrigerant in FIG. 5).

Moreover, the impulse force Fd of the spring 62 when the valve is completely closed is adjusted in the present patent so that the total sum of the pressure difference AP opening of the back pressure valve and a maximum saturation pressure Psm is equal to or less than the test pressure Prm of the tank 25, where the maximum saturation pressure Psm is the saturation pressure of the refrigerant corresponding to the maximum value of the atmospheric temperature at the location where the first and second valves are installed expansion 24, 26 (the outdoor unit 2 in the present patent). Specifically, the maximum saturation pressure Psm is a value obtained by converting the maximum atmospheric temperature (for example, approximately 50 ° C) that could be assumed at the location where the first and second expansion valves are installed 24, 26 ( the outdoor unit 2 in the present patent) at a saturation pressure of the refrigerant. The test pressure Prm is the test pressure of the tank 25, which has the lowest test pressure between the first expansion valve 24, the tank 25, and the second expansion valve 26 as the components that constitute the part of the circuit refrigerant 10 between the two expansion valves 24, 26 which includes the tank 25. The test pressure Prm of the tank 25 in the present patent is obtained by multiplying the nominal pressure of the tank 25 by a safety factor (for example, approximately 1, 5 times corresponding to a test pressure test). For the spring 62, the spring constant and the length of the spring LO in the inactive opening state of the back pressure valve (ie the length contracted from the free length) are adjusted so that the impulse force Fd in the inactive opening state of the backpressure valve it is equal to or less than a force Fum that pushes the needle 61 in the direction of needle retraction, generated when it is assumed that the needle 61 is subjected to a pressure difference which is the pressure of

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Prm test of tank 25 minus the maximum saturation pressure Psm. This pressure difference corresponding to the impulse force Fd in the inactive opening state of the back pressure valve is designated as the AP difference of the opening pressure of the back pressure valve. Because the test pressure Prm of the reservoir 25 in the present patent is obtained based on the nominal pressure of the reservoir 25 as described above, the pressure difference AP of the opening pressure of the back pressure valve, i.e. impulse force Fd of the spring while the valve is completely closed can be adjusted properly. Even assuming conditions of an atmospheric temperature so high that the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 that includes the tank 25 increases in pressure at the maximum saturation pressure Psm, the force Fu generated by the difference in pressure of the opening pressure of the back pressure valve to push the needle 61 in the direction of needle retraction will exceed the impulse force Fd of the spring 62 in the direction of advance of the needle before the pressure of the needle is exceeded. Prm test of reservoir 25, and the first expansion valve 24 will be in the active opening state of the back pressure valve. Therefore, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 which includes the tank 25 can be passed to the outdoor heat exchanger 23 before the test pressure Prm of the tank is exceeded 25, and the stagnation of liquid in the tank 25 can be avoided. Due to the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 which includes the tank 25 which is allowed to pass to the outdoor heat exchanger 23 , when there is a decrease in the pressure of the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 which includes the tank 25, a smaller force Fu that pushes the needle 61 in the direction of needle retraction is generated by the pressure difference AP of the back pressure valve opening, and the first expansion valve 24 returns to the inactive opening state of the contour valve rapression The cases of the first expansion valve 24 entering the active opening state of the back pressure valve can therefore be kept to the minimum necessary.

Therefore, in the refrigerant circuit 10 configured by connecting the compressor 21, the outdoor heat exchanger 23, the first expansion valve 24, the tank 25, the second expansion valve 26 (an opening / closing valve), and the indoor heat exchanger 41 in the air conditioner 1, the liquid stagnation in the tank 25 can be avoided without providing a liquid stagnation prevention tube, despite the use of full-closing expansion valves such as the first valve of expansion 24 and the second expansion valve 26. Moreover, in the air conditioner 1, liquid stagnation in the tank 25 can be properly avoided while taking into account the test pressure Prm of the tank 25.

<Structure to prevent liquid stagnation in the part between the liquid side shut-off valve and the second expansion valve>

Even when using a full shut-off expansion valve such as the second expansion valve 26 (an opening / closing valve), when both the liquid side shut-off valve 27 and the second expansion valve 26 are completely closed due to a setback such as an erroneous operation of the closing valve 27 on the liquid side (an opening / closing valve) and / or the second expansion valve 26, there is a risk that a liquid stagnation will occur in the part of the refrigerant circuit 10 between the shut-off valve 27 on the liquid side and the second expansion valve 26. To avoid said liquid stagnation in the part between the shut-off valve 27 on the liquid side and the second expansion valve 26, it must be It is possible for the refrigerant in the part of the refrigerant circuit 10 between the shut-off valve 27 on the liquid side and the second expansion valve 26 to be able to pass to the rest of the refrigerant circuit 10 when there is an increase in the refrigerant pressure in the part of the refrigerant circuit 10 between the shut-off valve 27 on the liquid side and the second expansion valve 26.

In view of this, in addition to preventing the stagnation of liquid in the tank 25 by providing the first expansion valve 24 in the refrigerant circuit 10 in a first state of arrangement as described above, first, the second expansion valve 26 is provided in the refrigerant circuit 10 in a second state of arrangement, in which the refrigerant from the reservoir 25 flows inwardly from the backward direction side of the needle of the valve seat 55 (the upper side of the seat 55 valve in the present patent), through the gap between the needle 61 and the valve seat 55, and outwardly towards the forward direction side of the valve seat 55 (the lower side of the valve seat 55 in the this patent) (see FIGS. 2 and 3). Specifically, the third coolant tube 35c for connecting to the reservoir 25 is connected to the first coolant outlet 53 of the second expansion valve 26, and the fourth coolant tube 35d for connecting with the shut-off valve 27 on the side of the liquid is connected to the second coolant outlet 54 of the second expansion valve 26, as shown in FIGS. 2 and 3. When the second expansion valve 26 provided in the refrigerant circuit 10 in the second disposition state is completely closed, these connections cause a pressure difference between the pressure of the refrigerant P1 in the space in the backward direction of the needle of the valve seat 55 (the upper chamber 52a of the valve in the present patent) and the pressure of the refrigerant P2 in the space in the forward direction side of the needle of the valve seat 55 (the lower chamber 52b of the valve in the present patent), where this pressure difference is indicated as the opening pressure difference of the AP back pressure valve (= P2 - P1). This pressure difference generates a pushing force Fu (an upward pushing force in the present patent) that will be exerted on the

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needle 61 in the reverse direction of the needle (see FIG. 4). The force Fu that pushes the needle 61 in the direction of backward movement of the needle due to this pressure difference of opening of the back pressure valve AP is used to provide a configuration in which the second expansion valve 26 provided in the refrigerant circuit 10 in the second state of arrangement is provided with a spring 62 to drive the needle 61 seated in the seat 55 of the valve in the direction of advance of the needle (downwards in the present patent) when the valve is completely closed, and when the force Fu that pushes the needle 61 in the direction of backward movement of the needle due to the difference in opening pressure of the back pressure valve AP exceeds the impulse force Fd of the spring 62 in the direction of needle advancement, needle 61 is released from its seat in valve seat 55 (see FIGS. 4 and 5). Specifically, the spring receiving element 63 is associated with the lower end of the valve shaft 64 to move in a solidary manner in the direction in which the needle 61 travels (vertically in the present patent), and the spring receiving element 63 and the needle 61 are vertically associated by the spring 62, as shown in FIGS. 3 to 5. A helical spring capable of expanding and contracting in the direction in which the needle 61 moves, is used in the present patent as the spring 62. This produces a configuration in which the needle 61 moves vertically due to the vertical displacement of the valve shaft 64, while the vertical distance between the valve shaft 64 and the needle 61 can expand and contract elastically. When the lower end of the valve shaft 64 reaches the lowest position in the travel range while the valve is completely closed, as shown in FIG. 4, the needle 61 becomes seated in the valve seat 55 while the spring 62 contracts to less than its free length but could still contract more (this state is hereinafter referred to as "inactive opening state of the back pressure valve "). The spring 62 thereby generates a force Fd that drives the needle 61 seated in the valve seat 55 in the forward direction of the needle, and the needle 61 is pushed against the valve seat 55 by the pulse force Fd of the spring 62. When the force Fu generated by the opening pressure difference of the AP backpressure valve to push the needle 61 in the direction of needle retraction then exceeds the pulse force Fd of the needle 61 in the forward direction of the needle while the valve is completely closed, the axis 64 of the valve does not move in the reverse direction of the needle (upwards in the present patent), the needle 61 is separated from the valve seat 55 in the direction of recoil of the needle (upwards in the present patent) while the spring 62 contracts even more in the inactive opening state of the back pressure valve, and the needle 61 is released from its seat in the seat 55 valve (this state is referred to below as the "active opening state of the back pressure valve"), as shown in FIG. 5. At this time, the length of the spring 62 contracts from the length LO in the inactive opening state of the back pressure valve to the length L in the active opening state of the back pressure valve. When there is an increase in the refrigerant pressure (equivalent to the pressure P2) in the part of the refrigerant circuit 10 between the shut-off valve 27 on the liquid side and the second expansion valve 26, the refrigerant in the part of the refrigerant circuit 10 between the shut-off valve 27 on the liquid side and the second expansion valve 26 can thus be passed to the reservoir 25 (see the arrow indicating the flow of the refrigerant in FIG. 5).

Furthermore, the pulse force Fd of the spring 62 while the valve is completely closed is adjusted, in the present patent, so that the total sum of the opening pressure difference of the AP back pressure valve and a maximum saturation pressure Psm is equal to or less than the minimum value of the test pressure Phm of the components constituting the part of the refrigerant circuit 10 of the second valve from expansion 26 to the closing valve 27 on the liquid side, where the maximum saturation pressure Psm is the saturation pressure of the refrigerant corresponding to the maximum value of the atmospheric temperature at the location where the second expansion valve 26 is installed (the outdoor unit 2 in the present patent). Specifically, the maximum saturation pressure Psm is a value obtained by converting the maximum atmospheric temperature (for example, approximately 50 ° C) that could be assumed at the location where the second expansion valve 26 is installed (the outdoor unit 2 in the present patent) at a saturation pressure of the refrigerant. The minimum value of the test pressure Phm is the test pressure of the component having the lowest test pressure between the liquid side shut-off valve 27, the fourth coolant tube 35d, and the second expansion valve 26 as the components that constitute the part of the refrigerant circuit 10 of the second expansion valve 26 to the closing valve 27 on the liquid side. When the components constituting the part of the refrigerant circuit 10 from the second expansion valve 26 to the shut-off valve 27 on the liquid side also include a filter, a pipe joint, and / or the like, a pressure value of Minimum Phm test that includes these components. The test pressures in the present patent are obtained by multiplying the nominal pressures of the components that constitute the part of the refrigerant circuit 10 from the second expansion valve 26 to the closing valve 27 on the liquid side by a safety factor (for example , approximately 1.5 times corresponding to a test pressure test). For the spring 62, the spring constant and the spring length LO in the inactive opening state of the back pressure valve (ie the contracted length of the free length) is adjusted so that the pulse force Fd in the Inactive state of opening of the back pressure valve is equal to or less than a Fum force that pushes the needle 61 in the direction of needle retraction, generated when it is assumed that the needle 61 is subjected to a pressure difference which is the value minimum of the test pressure Phm minus the maximum saturation pressure Psm. This pressure difference corresponding to the impulse force Fd in the inactive opening state of the back pressure valve is designated as the opening pressure difference of the back pressure valve AP. Because the test pressures are obtained based on the nominal pressures of the components that constitute the part of the refrigerant circuit 10 from the second expansion valve 26 to the shut-off valve 27 on the side of the

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As described above, the difference in opening pressure of the AP back pressure valve, that is, the impulse force Fd of the spring while the valve is completely closed, can be adjusted appropriately. Even assuming conditions of an atmospheric temperature so high that the refrigerant in the part of the refrigerant circuit 10 between the shut-off valve 27 on the liquid side and the second expansion valve 26 increases the pressure to the maximum saturation pressure Psm, the force Fu generated by the opening pressure difference of the AP backpressure valve to push the needle 61 in the direction of needle retraction will exceed the impulse force Fd of the spring 62 in the direction of needle advance before the pressure exceeds the minimum test pressure value Phm of the components constituting the part of the refrigerant circuit 10 from the second expansion valve 26 to the closing valve 27 on the liquid side, and the second expansion valve 26 will be in the active state of back pressure valve opening. Therefore, the refrigerant in the part of the refrigerant circuit 10 between the shut-off valve 27 on the liquid side and the second expansion valve 26 can be passed into the tank 25 before the pressure exceeds the test pressures of the components constituting the part of the refrigerant circuit 10 from the second expansion valve 26 to the shut-off valve 27 on the liquid side, and the liquid stagnation between the shut-off valve 27 on the liquid side and the second expansion valve 26 can be avoided There is a risk in the present patent that the refrigerant that is allowed to pass into the tank 25 generates an increase in pressure in the tank 25, but because the first expansion valve 24 is provided in the first state of disposal, the refrigerant will be allowed to pass to the outdoor heat exchanger 23 before the test pressure Prm of the tank 25 is exceeded. Because the refrigerant in the part of the refrigerant circuit 10 between the shut-off valve 27 on the liquid side and the second expansion valve 26 that is allowed to pass into the tank 25, when there is a decrease in the pressure of the refrigerant in the part of the refrigerant circuit 10 Between the shut-off valve 27 on the liquid side and the second expansion valve 26, a smaller force Fu that pushes the needle 61 in the direction of needle retraction is generated by the pressure difference of the opening of the back pressure valve AP , and the second expansion valve 26 returns to the inactive opening state of the back pressure valve. The cases of the second expansion valve 26 entering the active opening state of the back pressure valve can thus be kept to the minimum necessary.

Therefore, in the refrigerant circuit 10 configured by connecting the compressor 21, the outdoor heat exchanger 23, the first expansion valve 24, the tank 25, the second expansion valve 26 (an opening / closing valve), the valve of closing 27 of the liquid side (an opening / closing valve), and the indoor heat exchanger 41 in the air conditioner 1, liquid stagnation in the reservoir can be avoided

25 without providing a liquid stagnation prevention tube, and liquid stagnation between the closing valve 27 on the liquid side and the second expansion valve 26 can also be avoided.

(4) Modification 1

The air conditioner 1 of the previous embodiment (see FIGS. 1 and 2) is configured with the first expansion valve 24 and the second expansion valve 26 (an opening / closing valve) provided on the upstream sides and downstream of the reservoir 25, wherein the first expansion valve 24 is provided in a first disposition state and the second expansion valve 26 is provided in a second disposition state to prevent liquid stagnation in reservoir 25 and stagnation of liquid between the shut-off valve 27 on the liquid side (an open / close valve) and the second expansion valve 26.

However, if only liquid stagnation in the tank 25 is a concern, at least one of the first expansion valve 24 and the second expansion valve 26 is preferably provided in the refrigerant circuit 10 in the first disposition state. .

For example, the first expansion valve 24 may be provided in the second disposition state and the second expansion valve 26 may be provided in the first disposition state, as shown in FIG. 6. When the second expansion valve 26 is provided in the first disposition state and there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24,

26 which includes the tank 25, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 which includes the tank 25 can be passed to the indoor heat exchanger 41 to prevent liquid stagnation in the tank 25.

The first expansion valve 24 and the second expansion valve 26 may also both be provided in the first state of arrangement as shown in FIG. 7. When the first and second valve 24, 26 which includes the tank 25, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 which includes the tank 25 can be passed to the heat exchanger 23 outside and the indoor heat exchanger 41 to prevent liquid stagnation in the tank 25.

Therefore, in the refrigerant circuit 10 of the present modification, configured by connecting the compressor 21, the outdoor heat exchanger 23, the first expansion valve 24, the tank 25, the second expansion valve 26 (an opening valve / closure), and the indoor heat exchanger 41, liquid stagnation in the tank 25 can be avoided without providing a liquid stagnation prevention tube, to

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In spite of the use of full closing expansion valves such as the first expansion valve 24 and the second expansion valve 26.

(5) Modification 2

In the air conditioner 1 (see FIG. 1) of the previous embodiment and Modification 1, a gas purge valve 30a could be provided to purge refrigerant from the upper space of the tank 25, as shown in FIG. 8.

For example, the refrigerant circuit 10 is provided with a gas purge tube 30 to guide the intermediate pressure refrigerant gas in the accumulated refrigeration cycle in the tank 25 towards the intake tube 31 of the compressor 21. The purge tube 30 of the gas is provided to connect the upper part of the tank 25 and an intermediate part of the intake pipe 31. A gas purge valve 30a is provided in the gas purge tube 30 together with a capillary tube 30b and a valve 30c anti-return The gas purge valve 30a is a valve that can be controlled to open and close to activate and deactivate the flow of refrigerant in the gas purge tube 30, and an electromagnetic valve is used in the present patent. The capillary tube 30b is a mechanism for depressurizing the refrigerant gas accumulated in the tank 25 to a low pressure in the refrigeration cycle, and in the present patent a capillary tube of thinner diameter than the gas purge tube 30 is used. The non-return valve 30c is a valve mechanism to allow only the flow of refrigerant from the side of the tank 25 to the side of the intake tube 31, and a non-return valve is used in the present patent.

In this configuration too, there is a risk of liquid stagnation in the tank 25 when all, the first expansion valve 24, the second expansion valve 26 (an opening / closing valve), and the gas purge valve 30a are They are completely closed.

In view of this, in a configuration having said gas purge valve 30a, at least one of the first expansion valve 24 and the second expansion valve 26 is provided in the refrigerant circuit 10 in the first disposition state , similar to the previous embodiment and Modification 1 (see FIGS. 2, 6, and 7).

Therefore, in the refrigerant circuit 10 of the present modification, configured by connecting the compressor 21, the outdoor heat exchanger 23, the first expansion valve 24, the tank 25, the second expansion valve 26 (an opening valve / closure), the indoor heat exchanger 41, and the gas purge valve 30a, liquid stagnation in the reservoir 25 can be avoided without providing a liquid stagnation prevention tube, despite using shut-off expansion valves complete as the first expansion valve 24 and the second expansion valve 26. Liquid stagnation in reservoir 25 can also be avoided in the present patent without providing a liquid stagnation prevention tube, and liquid stagnation can also be avoided. between the shut-off valve 27 on the liquid side (an open / close valve) and the second expansion valve 26 (a check valve opening / closing) (see Fig. 2), providing the first expansion valve 24 in the first disposition state and providing the second expansion valve 26 in the second disposition state.

(6) Modification 3

In the air conditioner 1 of Modification 2 above (see FIG. 8), it is conceivable to use a full shut-off expansion valve such as the gas purge valve 30a, similar to the first expansion valve 24 and / or the second expansion valve 26 (an opening / closing valve), as shown in FIG. 9. A full shut-off expansion valve having the same structure as the first expansion valve 24 and / or the second expansion valve 26 (see FIGS. 3 to 5) would be used in the present patent for the purge valve of gas 30a.

In such a configuration, if only the stagnation of liquid in the tank 25, at least one of between the first expansion valve 24, the second expansion valve 26, and the gas purge valve 30a is preferably provided in the refrigerant circuit 10 in the first state of disposal.

For example, first, the first expansion valve 24 may be provided in the first disposition state, and the second expansion valve 26 and the gas purge valve 30a may be provided in the second disposition state, such as is shown in FIG. 10. The maximum saturation pressure used to adjust the force of the spring 62 in the present patent is the saturation pressure of the refrigerant corresponding to the maximum value of the atmospheric temperature at the location (the outdoor unit 2 in the present patent) in the that the tank 25, the first expansion valve 24, the second expansion valve 26, and the gas purge valve 30a are installed. When the first expansion valve 24 is provided in the first disposition state and there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit 10 between the two

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expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25 may be allowed to pass to the outdoor heat exchanger 23 to avoid liquid stagnation in the tank 25. In this case, the liquid stagnation in the tank 25 can be avoided, and the liquid stagnation between the shut-off valve can be avoided 27 on the liquid side (an opening / closing valve) and the second expansion valve 26 because the second expansion valve 26 is provided in the second disposition state.

The first expansion valve 24 may be provided in the first disposition state, and the second expansion valve 26 and the gas purge valve 30a may be provided in the second disposition state in FIG. 11. When the first expansion valve 24 is provided in the first disposition state and there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a which includes the tank 25, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25 can be passed to the indoor heat exchanger 41 for avoid liquid stagnation in the tank 25.

The gas purge valve 30a may also be provided in the first disposition state, and the first expansion valve 24 and the second expansion valve 26 may be provided in the second disposition state, as shown in FIG. 12. When the gas purge valve 30a is provided in the first state of disposal and there is an increase in the refrigerant pressure in the refrigerant part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the valve gas purge 30a that includes the tank 25, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25 can be passed to the compressor 21 to avoid liquid stagnation in reservoir 25. In this case, liquid stagnation in reservoir 25 can be avoided, and liquid stagnation between the shut-off valve 27 on the liquid side and the second expansion valve 26 can be avoided due to that the second expansion valve 26 is provided in the second disposition state.

The first expansion valve 24 and the gas purge valve 30a may also be provided in the first disposition state, and the second expansion valve 26 may be provided in the second disposition state, as shown in FIG. 13. When the first expansion valve 24 and the gas purge valve 30a are provided in the first disposition state and there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25 can be passed to the outdoor heat exchanger 23 and the compressor 21 to prevent liquid stagnation in the tank 25. In this case, the liquid stagnation in the tank 25 can be avoided and the liquid stagnation between the shut-off valve 27 on the side of the liquid and the second expansion valve 26 can be avoided because the second expansion valve 26 is provided in the second disposition state.

The second expansion valve 26 and the gas purge valve 30a may also be provided in the first disposition state, and the first expansion valve 24 may be provided in the second disposition state, as shown in FIG. 14. When the second expansion valve 26 and the gas purge valve 30a are provided in the first disposition state and there is an increase in the refrigerant pressure in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25 can be passed to the indoor heat exchanger 41 and the compressor 21 to prevent liquid stagnation in the tank 25.

The first expansion valve 24 is provided in the first disposition state. The second expansion valve 26 may also be provided in the first disposition state, and the gas purge valve 30a may be provided in the second disposition state, as shown in FIG. 15. When the first expansion valve 24 and the second expansion valve 26 are provided in the first state of arrangement and there is an increase in the pressure of the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25, the refrigerant in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 and the gas purge valve 30a that includes the tank 25 can be passed to the heat exchanger 23 outside and heat exchanger 41 inside to avoid the stagnation of liquid in the tank 25.

The first expansion valve 24 is provided in the first disposition state. The second expansion valve 26 and the gas purge valve 30a may be provided in the first disposition state, as shown in FIG. 16. When the two expansion valves 24, 26 and the gas purge valve 30a are provided in the first disposition state and there is an increase in the refrigerant pressure in the part of the refrigerant circuit 10 between the two expansion valves 24, 26 which includes the tank 25, the refrigerant in the

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part of the refrigerant circuit 10 between the two expansion valves 24, 26 that includes the tank 25 can be passed to the outdoor heat exchanger 23, the indoor heat exchanger 41, and the compressor 21 to prevent liquid stagnation in the deposit 25.

Therefore, in the refrigerant circuit 10 of the present modification, configured by connecting the compressor 21, the outdoor heat exchanger 23, the first expansion valve 24, the tank 25, the second expansion valve 26 (an opening valve / closure), the indoor heat exchanger 41, and the gas purge valve 30a, liquid stagnation in the reservoir 25 can be avoided without providing a liquid stagnation prevention tube, despite using shut-off expansion valves complete as the first expansion valve 24, the second expansion valve 26, and the gas purge valve 30a. The stagnation of liquid in the reservoir 25 in the present patent can also be avoided without providing a liquid stagnation prevention tube, and the stagnation of liquid between the shut-off valve 27 on the liquid side (an open / close valve can be avoided). ) and the second expansion valve 26 providing the first expansion valve 24 and / or the gas purge valve 30a in the first disposition state and providing the second expansion valve 26 in the second disposition state.

(7) Modification 4

In the air conditioner 1 of the previous embodiment and Modifications 1 to 3 (see FIGS. 1 to 16), a structure is used to prevent the stagnation of liquid in the tank 25 (where the first expansion valve 24, the second expansion valve 26, and / or the gas purge valve 30a are installed in the first disposition state), in the event that the first expansion valve 24 and the second expansion valve 26 (an opening valve / closure) composed of full closing expansion valves, are provided on the upstream and downstream sides of the tank 25 (including the configuration presented by the gas purge valve 30a), and the closure valve 27 on the liquid side (an opening / closing valve) is provided between the second expansion valve 26 and the indoor heat exchanger 41.

However, if only liquid stagnation in tank 25 is a concern, when the second expansion valve 26 is open but both the first expansion valve 24 (which includes the configuration presented by the gas purge valve 30a) and the closing valve 27 on the liquid side becomes completely closed due to a setback such as an erroneous operation of the closing valve 27 on the liquid side (an opening / closing valve), it is assumed that there could be cases of stagnation of liquid in the tank 25. Specifically, in a conceivable case, the first expansion valve 24 composed of a full shut-off expansion valve is provided in the second disposition state (when there is also a gas purge valve 30a composed of a full shut-off expansion valve, a gas purge valve 30a is also provided in the second state of arrangement), and the second expansion valve 26 composed of a full shut-off expansion valve in the first disposition state (see FIGS. 6 and 11).

Therefore, assuming cases where there is a liquid stagnation in the tank 25 due to a setback such as an erroneous operation of the closing valve 27 on the liquid side, it is preferable that the first expansion valve 24 composed of a valve Full shut-off expansion valve is provided in the first disposition state (when there is also a gas purge valve 30a composed of a full shut-off expansion valve, the first expansion valve 24 and / or the gas purge valve 30a they are provided in the first state of disposition) (see FIGS. 2, 7, 10, and 12 to 16).

(8) Modification 5

Taking into account the cases of liquid stagnation in the tank 25 due to a setback such as an erroneous operation of the closing valve 27 on the liquid side (an opening / closing valve) as in Modification 4 above, a first valve expansion 24 composed of a full shut-off expansion valve should be arranged (such as the gas purge valve 30a when there is a gas purge valve 30a composed of a full shut-off expansion valve), assuming that the liquid stagnation in the tank 25 it will take place even if there is no second expansion valve 26 (an opening / closing valve), as shown in FIGS. 17 and 18.

In view of this, the first expansion valve 24 composed of a full closing expansion valve and / or the gas purge valve 30a composed of a full closing expansion valve is provided herein in the first state. of disposition Specifically, the first expansion valve 24 is provided in the first disposition state as shown in FIG. 19 when there is no gas purge valve 30a composed of a full shut-off expansion valve (see FIG. 17), and the first expansion valve 24 and / or the gas purge valve 30a are provided in the first disposition status as shown in FIGS. 20 to 22 when there is a gas purge valve 30a composed of a full shut-off expansion valve (see FIG. 18).

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Therefore, in the refrigerant circuit 10 of the air conditioner 1, configured by connecting the compressor 21, the outdoor heat exchanger 23, the first expansion valve 24, the tank 25, the closing valve 27 on the liquid side, and the indoor heat exchanger 41 (also including the gas purge valve 30a), the liquid stagnation in the tank 25 can be avoided without providing a liquid stagnation prevention tube, despite using an expansion valve of full shut-off as the first expansion valve 24 (and to use a full shut-off expansion valve like the gas purge valve 30a when there is a gas purge valve 30a).

Industrial applicability

The present invention is widely applicable in air conditioners that have a refrigerant circuit configured by connecting a compressor, an outdoor heat exchanger, a first expansion valve, a reservoir, an opening / closing valve, and a heat exchanger of inside.

List of reference signs

1 air conditioner

10 Refrigerant circuit

21 Compressor

23 Outdoor heat exchanger 41 Indoor heat exchanger

24 First expansion valve

26 Second expansion valve (opening / closing valve)

27 Liquid side shut-off valve (open / close valve)

30th Gas Purge Valve

52a Upper valve chamber (space in the backward direction side of the valve seat needle) 52b Lower valve chamber (space in the forward direction side of the valve seat needle)

55 Valve seat

61 Needle

62 Spring List of citations Patent bibliography

[Patent bibliography 1] Japanese unexamined publication open for public inspection No. H10-132393

Claims (12)

10 fifteen twenty 25 30 35 40 Four. Five 1. Air conditioner (1) having a refrigerant circuit (10) configured by connecting a compressor (21), an outdoor heat exchanger (23), a first expansion valve (24), a tank (25), an opening / closing valve (26, 27), and an indoor heat exchanger (41); where a full closing expansion valve is used that is completely closed by a needle (61) that sits on a valve seat (55) as the first expansion valve (24), and the first expansion valve (24) is provided in the refrigerant circuit (10) in the first state of disposition in which the refrigerant in the tank (25) flows inward from the direction of advance of the needle of the valve seat (55), and outwards towards the reverse direction of the needle of the valve seat (55) through a gap between the needle and the valve seat (55), where the direction of advance of the needle is the direction in which the needle moves when the needle sits in the valve seat (55), and the needle backward direction is the direction in which the needle moves when the needle retracts from the valve seat (55); The first expansion valve (24) provided in the refrigerant circuit (10) in the first state of arrangement comprises a spring (62) for driving the needle seated in the valve seat (55) in the direction of advance of the needle when the valve is completely closed, and is configured so that the needle is released from being seated in the valve seat (55) when the impulse force of the spring (62) in the direction of advance of the needle is exceeded by a force that pushes the needle in the direction of backward movement of the needle, as generated by the difference in opening pressure of the back pressure valve, which is the difference between the pressure of the refrigerant in a space (52a) on the side of the backward direction of the valve seat needle (55) and the refrigerant pressure in a space (52b) on the forward direction side of the valve seat needle (55); Y the first expansion valve (24) is provided in a part of a refrigerant liquid tube (35) that is located between the outdoor heat exchanger (23) and the tank (25); characterized by that the tank (25) is provided between the first expansion valve (24) and the opening / closing valve (26, 27). 2. Air conditioning apparatus (1) according to claim 1, wherein The opening / closing valve (26, 27) is a closing valve (27) on the liquid side. 3. Air conditioning apparatus (1) according to claim 1, wherein the opening / closing valve (26, 27) is a second expansion valve (26); the second expansion valve (26) is a full closing expansion valve that is completely closed by a needle (61) that sits in a valve seat (55); the second expansion valve (26) in this case is provided in the refrigerant circuit (10) in a first state of arrangement in which the refrigerant in the tank (25) flows inward from the direction of advance of the valve seat needle (55), and outward toward the backward direction side of the valve seat needle (55) through a gap between the needle (61) and the valve seat (55) , where the needle forward direction is the direction in which the needle (61) moves when the needle (61) sits in the valve seat (55), and the needle backward direction is the direction wherein the needle (61) travels when the needle (61) retracts from the valve seat (55); Y The second expansion valve (26) provided in the refrigerant circuit (10) in the first state of arrangement comprises a spring (62) for driving the needle (61) seated in the valve seat (55) in the direction of travel of the needle when the valve is completely closed, where the second expansion valve (26) is configured so that the needle (61) is released from its seat in the valve seat (55) when the spring force (62) in the direction of advance of the needle it is exceeded by a force that pushes the needle (61) in the direction of backward movement of the needle as it is generated by the difference in opening pressure of the back pressure valve, which is the difference between the coolant pressure in a space (52a) on the backward direction side of the seat needle 10 fifteen twenty 25 30 35 40 (55) valve and coolant pressure in a space (52b) on the forward direction side of the valve seat needle (55). 4. Air conditioning apparatus (1) according to any of claims 1 to 3, wherein the impulse force of the spring (62) when the valve is completely closed is adjusted so that the total sum of the opening pressure difference of the back pressure valve and a maximum saturation pressure is equal to or less than the pressure of tank test (25), where the maximum saturation pressure is the saturation pressure of the refrigerant that corresponds to the maximum value of the atmospheric temperature at the location where the tank (25) is installed, the first expansion valve (24 ), and the opening / closing valve (26, 27). 5. Air conditioning apparatus (1) according to claim 1, wherein The refrigerant circuit (10) also comprises a gas purge valve (30a) for purging the refrigerant from the upper space of the tank (25); a full shut-off expansion valve that is completely closed by a needle (61) that sits in a valve seat (55) is used as the gas purge valve (30a); The gas purge valve (30a) in this case is provided in the refrigerant circuit (10) in a first state of disposition in which the refrigerant in the tank (25) flows inwards from the side of the forward direction of the valve seat needle (55), and outward toward the backward direction side of the valve seat needle (55) through a gap between the needle (61) and the seat (55) of valve, where the needle forward direction is the direction in which the needle (61) moves when the needle (61) sits in the valve seat (55), and the needle backward direction is the direction in which the needle (61) moves when the needle (61) retracts from the valve seat (55); Y The gas purge valve (30a) provided in the refrigerant circuit (10) in the first state of arrangement comprises a spring (62) for driving the needle (61) seated in the valve seat (55) in the forward direction of the needle when the valve is completely closed, where the gas purge valve (30a) is configured so that the needle (61) is released from being seated in the valve seat (55) when the spring impulse force (62) in the direction of advance of the needle is exceeded by a force that pushes the needle (61) in the direction of backward movement of the needle as generated by the difference in opening pressure of the back pressure valve, which is the difference between the pressure of the refrigerant in a space (52a) on the backward direction side of the valve seat needle (55) and the pressure of the refrigerant in a space (52b) on the side of the forward direction of the valve seat needle (55). 6. Air conditioning apparatus (1) according to claim 5, wherein The opening / closing valve (26, 27) is a closing valve (27) on the liquid side. 7. Air conditioning apparatus (1) according to claim 1, wherein the opening / closing valve (26, 27) is a second expansion valve (26); the refrigerant circuit (10) further comprises a gas purge valve (30a) to purge the refrigerant from the upper space of the tank (25); the full closing expansion valves that are each completely closed by a needle (61) that sits in a valve seat (55) are used for the second expansion valve (26) and the gas purge valve (30a ); at least one of the second expansion valve (26) and the gas purge valve (30a) in this case is provided in the refrigerant circuit (10) in a first state of disposal in which the refrigerant in the tank ( 25) flows inwardly from the forward direction side of the valve seat needle (55), and outwardly toward the reverse direction side of the valve seat needle (55) through a gap between the needle (61) and the valve seat (55), where the direction of advance of the needle is the direction in which the needle (61) moves when the needle (61) moves when said needle (61 ) retracts from the valve seat (55); Y 10 fifteen twenty 25 30 35 40 Four. Five the second expansion valve (26) and / or the gas purge valve (30a) provided in the refrigerant circuit (10) in the first state of arrangement comprises a spring (62) for driving the needle (61) seated in the valve seat (55) in the forward direction when the valve is completely closed, where the second expansion valve (26) and / or the gas purge valve (30a) are configured so that the needle (61) is released from being seated in the valve seat (55) when the impulse force of the spring (62) in the direction of advance of the needle is exceeded by a force that pushes the needle (61) in the direction of backward movement of the needle, as generated by a difference in the opening pressure of the back pressure valve, which is the difference between the pressure of the refrigerant in a space (52a) on the backward direction side of the seat needle (55) of valve and coolant pressure in a space (52b) on the forward direction side of the valve seat needle (55). 8. Air conditioning apparatus (1) according to any of claims 5 to 7, wherein the impulse force of the spring (62) when the valve is completely closed is adjusted so that the total sum of the opening pressure difference of the back pressure valve and a maximum saturation pressure is equal to or less than the pressure of tank test (25), where the maximum saturation pressure is the saturation pressure of the refrigerant corresponding to the maximum value of the atmospheric temperature at the location where the tank (25) is installed, the first expansion valve (24) , the opening / closing valve (26, 27), and the gas purge valve (30a). 9. Air conditioning apparatus (1) according to claim 4 or 8, wherein The test pressure of the tank (25) is a pressure value obtained by multiplying the nominal pressure of the tank (25) by a safety factor. 10. Air conditioning apparatus (1) according to claim 1 or 5, wherein The opening / closing valves (26, 27) are a second expansion valve (26) and a closing valve (27) on the liquid side connected between the second expansion valve (26) and the heat exchanger (41) indoor; a full shut-off expansion valve is used that is completely closed by a needle (61) that sits in a valve seat (55) like the second expansion valve (26), where the second expansion valve (26) is It is provided in the refrigerant circuit (10) in a second state of arrangement in which the refrigerant in the tank (25) flows inward from the backward direction side of the valve seat needle (55), and towards out towards the forward direction side of the valve seat needle (55) through a gap between the needle (61) and the valve seat (55); Y The second expansion valve (26) provided in the refrigerant circuit (10) in the second state of arrangement comprises a spring (62) for driving the needle seated in the valve seat (55) in the direction of advance of the needle when The valve is completely closed, where the second expansion valve (26) is configured so that the needle (61) is released from being seated in the valve seat (55) when the force of the spring (62) in the direction of advance of the needle is exceeded by a force that pushes the needle (61) in the direction of backward movement of the needle as generated by the pressure difference of the back pressure valve, which is the difference between the pressure of the coolant in a space (52a) on the backward direction side of the valve seat needle (55) and the coolant pressure in a space (52b) on the side of the forward direction of the seat needle (55) Valve 11. Air conditioning apparatus (1) according to claim 10, wherein the impulse force of the spring (62) of the second expansion valve (26) when the valve is completely closed is adjusted so that the total sum of a maximum saturation pressure and the difference in the opening pressure of the valve back pressure of the second expansion valve (26) is equal to or less than the minimum value of the test pressures of the components constituting the part of the refrigerant circuit (10) from the second expansion valve (26) to the closing valve (27) on the liquid side, where the maximum saturation pressure is the saturation pressure of the refrigerant corresponding to the maximum value of the atmospheric temperature at the location where the second expansion valve (26) and the shut-off valve are installed (27) of the liquid side. 12. Air conditioning apparatus (1) according to claim 11, wherein The test pressures of the components constituting the part of the refrigerant circuit (10) from the second expansion valve (26) to the closing valve (27) on the liquid side are pressure values obtained by multiplying the nominal pressures of the components that constitute the part of the refrigerant circuit (10) from the second expansion valve to the closing valve (27) on the liquid side by a safety factor.