JPH05157405A - Expansion valve - Google Patents

Abstract

PURPOSE:To improve the response characteristic in the action of a temperature sensing action means by providing a heat transfer delaying means which is for making longer the time required for the transmission of a change in temperature of refrigerant to a temperature sensing drive means between the flow channel of the refrigerant that is delivered to an evaporator and temperature sensing drive means. CONSTITUTION:In refrigerating cycle an expansion valve is for controlling automatically the flow rate of refrigerant that enters an evaporator. When the temperature of the refrigerant that flows in a low pressure channel 12 drops, the temperature of a diaphragm 32 falls and the saturated gas in a temperature sensing chamber 30 condenses on the inner surface of the diaphragm 32. Then, since the pressure in the temperature sensing chamber 30 falls, a rod 28 is pushed by a spring 24 and a ball valve 25 gets nearer a valve seat 23 and the area of the flow channel of the coolant is throttled. In this case an intermediate tap body 38 is placed between the low pressure channel 12 and temperature sensing chamber 30 and the time required for transmitting a temperature change of the coolant to the temperature sensing chamber 30 is prolonged. With this arrangement the diaphragm 32 and ball valve 25 act with an accurate response speed for a change in the refrigerant temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion valve for automatically controlling the amount of refrigerant entering the evaporator in response to the temperature of the refrigerant sent from the evaporator to the compressor during the refrigeration cycle. Regarding

[0002]

2. Description of the Related Art An expansion valve of this type has a greenhouse which is filled with a saturated vapor gas which is the same as or similar to a refrigerant flowing through a refrigeration cycle and which is disposed in an outlet passage of an evaporator.
A valve mechanism that is driven by the displacement of the diaphragm that forms one wall of the greenhouse is provided, and the valve mechanism is driven by thermally expanding and contracting the saturated vapor gas in the greenhouse by the temperature change of the refrigerant that exits the evaporator. Then, the amount of refrigerant entering the evaporator is automatically controlled.

[0003]

However, if the temperature change of the refrigerant sent from the evaporator is transmitted to the temperature-sensitive chamber too quickly, the small pulsation that occurs in the refrigerant such as a slight change in the heating degree of the refrigerant will remain in the valve. There was a drawback that it was transmitted to the opening / closing operation of the mechanism and the valve operation became extremely unstable.

Therefore, the present invention provides an expansion valve capable of controlling the amount of the refrigerant sent to the evaporator by a stable operation even if the refrigerant sent from the evaporator has a minute temperature change. To aim.

[0005]

In order to achieve the above object, the expansion valve of the present invention has a valve mechanism for changing the flow rate of the refrigerant sent to the evaporator and the refrigerant sent from the evaporator. In the expansion valve provided with temperature-sensitive drive means for driving the valve mechanism by thermally expanding or thermally contracting the saturated vapor gas which is arranged so as to sense the temperature of the Between the flow path of the coming refrigerant and the temperature sensitive driving means, heat for increasing the time required for the temperature change of the refrigerant sent from the evaporator to be transmitted to the temperature sensitive driving means. It is characterized in that a transmission delay means is provided.

The heat transfer delay means may be a member having a low heat conductivity which regulates the amount of the refrigerant which is sent from the evaporator and comes into contact with the temperature sensitive drive means.

[0007]

The valve mechanism for changing the flow rate of the refrigerant sent to the evaporator is driven by the temperature sensitive driving means arranged so as to detect the temperature of the refrigerant sent from the evaporator.

The time required for the temperature change of the refrigerant sent from the evaporator to be transmitted to the temperature-sensitive drive means is lengthened by the heat transfer delay means, so that the refrigerant is sent out from the evaporator. The responsiveness of the operation of the heat-sensitive operation means to the temperature change of the refrigerant coming in is low, and therefore the valve mechanism does not react to the minute temperature change of the refrigerant sent out from the evaporator.

[0009]

Embodiments will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. In the figure, 1 is an evaporator, 2 is a compressor, 3 is a condenser, and 4
Is a receiver connected to the outlet side of the condenser 3 and containing a high-pressure liquid refrigerant, and 10 is an expansion valve, which form a refrigeration cycle.

The block 11 of the expansion valve 10 includes an evaporator 1
A low-pressure passage 12 for passing a low-temperature low-pressure refrigerant sent from the compressor 2 to the compressor 2 and a passage 13 for adiabatically expanding the high-temperature high-pressure refrigerant sent to the evaporator 1 are formed.

The low-pressure passage 12 has one end (inlet side) 12a connected to the outlet of the evaporator 1 and the other end (outlet side) 12b connected to the inlet of the compressor 2. The passage 13 for adiabatically expanding the high-pressure side refrigerant has one end (inlet side) 13 a connected to the outlet of the liquid receiver 4 and the other end (outlet side) 13 b connected to the inlet of the evaporator 1.

The low pressure passage 12 and the passage 13 for adiabatic expansion are formed in parallel with each other, and a through hole 14 perpendicular to the passage is formed between the two passages 12, 13.
Further, a greenhouse 30 is attached to the opening formed so as to pass outward from the low pressure passage 12.

A valve mechanism 20 is provided inside the passage 13 for adiabatic expansion from the through hole 14. On the other hand, a valve seat 23 is formed at the center of the passage 13 for adiabatic expansion, and when the ball valve 25 biased from below by the coil spring 24 toward the valve seat 23 closes the valve seat 23, The passage 13 for adiabatic expansion closes.

A ball valve support 26 supports the ball valve 25. Reference numeral 27 is an adjusting nut screwed with the block 11 to adjust the biasing force of the coil spring 24. Reference numeral 21 is an O-ring for sealing.

The rod 28 inserted into the through hole 14 is provided so as to be slidable in the axial direction, and the upper end thereof is at the greenhouse 3
It reaches 0, and the lower end is in contact with the upper end of the ball valve 25.
Therefore, if the rod 28 pushes the ball valve 25 to move it downwards against the biasing force of the coil spring 24, the passage 13 for adiabatic expansion is opened, and the rod 28 is opened.
The passage area of the passage 13 changes in accordance with the moving amount of, and the amount of the refrigerant supplied to the evaporator 1 changes.

The rod 28 is made of a material such as stainless steel whose thermal conductivity is much lower than that of aluminum or the like. The diameter of the rod 28 is kept to the minimum necessary in terms of strength and its cross-sectional area is small. It is formed to be as small as possible. Therefore, the temperature of the refrigerant flowing through the low-pressure passage 12 is transmitted to the greenhouse 30 only slightly via the rod 28. The rod 28 may be formed in a hollow cross-sectional shape to reduce the cross-sectional area.

Reference numeral 16 is an O-ring for sealing so that the low pressure passage 12 and the passage 13 for adiabatic expansion do not communicate with each other through the periphery of the rod 28,
It is pressed and fixed by a small coil spring 18 via a pressing plate 17. Reference numeral 19 is a ring made of a leaf spring material fixed to the block 11 to receive the end of the coil spring 18.

The greenhouse 30 is airtightly surrounded by a housing 32 made of a thick metal plate and a diaphragm 32 made of a flexible metal thin plate (for example, a stainless steel plate having a thickness of 0.1 mm). Then, in the central portion of the lower surface of the diaphragm 32, the top portion 2 of the rod 28 formed in a large dish shape is formed.
8a is in contact.

In the greenhouse 30, passages 12, 13 are provided.
A saturated vapor state gas having the same or similar properties as the refrigerant flowing therein is filled, and the gas filling injection hole is closed by a blind plug 34.

Reference numeral 33 denotes a greenhouse-mounting seat for mounting the greenhouse 30 on the block 11, the outer peripheral portion of which is hermetically welded to the housing 31 and the diaphragm 32 over the entire periphery to form an inner cylindrical portion. Screw part 3
3a is screwed onto the block 11. 36 is an O-ring for sealing.

An intermediate plug 38 (heat transfer delay means) made of a rubber material or a plastic material having a low heat conductivity is fixed to the block 11 between the low-pressure passage 12 and the greenhouse 30. Therefore, if the intermediate plug 38 does not exist, a large amount of the refrigerant flowing through the low-pressure passage 12 goes around to the greenhouse 30 side and comes into direct contact with the greenhouse 30. It is regulated to go around.

However, there is a gap between the rod 39 and the hole 39 formed in the intermediate plug body 38 for allowing the rod 28 to pass therethrough, and the intermediate plug body 38 also has a low pressure passage 12 and a greenhouse 30.
Since a plurality of vent holes 40 that communicate with the side are formed by penetrating therethrough, such gaps between the holes 39 and the vent holes 40 are provided.
A small amount of the refrigerant flowing through the low-pressure passage 12 goes around to the greenhouse 30 side.

Therefore, the temperature of the refrigerant flowing through the low-pressure passage 12 is transmitted to the greenhouse 30 by a small amount of the refrigerant flowing around the greenhouse 39 side through the gap between the holes 39 and the ventilation holes 40. However, since the amount of the refrigerant used for heat transfer is small in this way, it takes time for the temperature change of the refrigerant flowing in the low-pressure passage 12 to be transferred to the greenhouse 30.

As described above, without the intermediate plug 38, the temperature change of the refrigerant flowing in the low-pressure passage 12 is transmitted to the greenhouse 30 in about 1 to 2 seconds. Delayed to tens of seconds. Incidentally. The vent 40 is
You may increase or decrease depending on the situation. Also,
The intermediate plug 38 may be formed of a breathable heat insulating material or the like.

In the expansion valve constructed as described above,
When the temperature of the refrigerant flowing in the low-pressure passage 12 decreases, the temperature of the diaphragm 32 also decreases, and the saturated vapor gas in the greenhouse 30 condenses on the inner surface of the diaphragm 32. Then,
Since the pressure inside the temperature-sensing greenhouse 30 decreases, the rod 28 is pushed by the coil spring 24 and moves, and as a result, the ball valve 2
Since 5 approaches the valve seat 23 and the flow passage area of the refrigerant decreases, the flow rate of the refrigerant flowing into the evaporator 1 decreases.

When the temperature of the refrigerant flowing in the low pressure passage 12 rises, the ball valve 25 is moved to the valve seat 23 by the operation reverse to the above.
The area of the flow path of the refrigerant increases away from, and the flow rate of the refrigerant flowing into the evaporator 1 increases.

However, since it takes time for the temperature change of the refrigerant flowing in the low pressure passage 12 to be transmitted to the temperature-sensitive chamber 30, the diaphragm 32 and the rod 28 and the ball valve 25 which operate following it are provided in the low pressure passage. It operates at a very slow response speed to the temperature change of the refrigerant flowing inside 12, and does not react to the minute temperature change of the refrigerant.

FIG. 2 shows a second embodiment of the present invention, in which the intermediate plug 38 is replaced by a rod 2 formed in a dish shape.
A thick heat insulating material 48 is fixed to the back surface of the top portion 28a of No. 8 so that only a small gap for the refrigerant flowing in the low-pressure passage 12 to go around to the greenhouse 30 side is left around. Even with this configuration, the same effect as that of the above-described first embodiment can be obtained.

[0030]

According to the expansion valve of the present invention, the responsiveness of the operation of the temperature-sensitive drive means to the temperature change of the refrigerant sent from the evaporator is low, so that the valve mechanism is sent from the evaporator. It has an excellent effect that it does not react to a minute temperature change of the refrigerant and can control the amount of the refrigerant sent to the evaporator by a very stable operation.

[Brief description of drawings]

FIG. 1 is a sectional view of an expansion valve according to a first embodiment.

FIG. 2 is a partial sectional view of an expansion valve according to a second embodiment.

[Explanation of symbols]

 1 Evaporator 25 Ball Valve 28 Rod 30 Heat Sensitive Chamber 32 Diaphragm 38 Intermediate Plug

Claims (2)

[Claims] 1. A valve mechanism for changing the flow rate of the refrigerant sent to the evaporator, and a saturated vapor gas which is arranged so as to detect the temperature of the refrigerant sent from the evaporator and which is enclosed inside. In an expansion valve provided with temperature-sensitive drive means for driving the valve mechanism by thermal expansion or thermal contraction, between the flow path of the refrigerant sent from the evaporator and the temperature-sensitive drive means, An expansion valve provided with heat transfer delay means for increasing the time required for the temperature change of the refrigerant sent from the evaporator to be transferred to the temperature sensitive drive means. 2. The expansion valve according to claim 1, wherein the heat transfer delay means is a member having a low thermal conductivity which regulates the amount of the refrigerant which is sent from the evaporator and comes into contact with the temperature sensitive driving means.