JP6387029B2 - Four-way valve and refrigeration cycle apparatus provided with the same - Google Patents

Description

  The present invention relates to a four-way valve and a refrigeration cycle apparatus including the same.

  There is known a refrigeration cycle apparatus that enables a cooling operation and a heating operation by switching a refrigerant flow path in which a compressor, an indoor heat exchanger, an expansion valve, an outdoor heat exchanger, and the like are connected by piping. Many refrigeration cycle apparatuses capable of cooling and heating operation include a four-way valve on the refrigerant flow path as a part that changes the circulation direction of the refrigerant by switching the refrigerant flow path.

  The four-way valve has a high-pressure side conduit communicating with the compressor discharge side, a low-pressure side conduit communicating with the compressor suction side, an indoor side conduit communicating with the indoor heat exchanger, and an outdoor heat exchange. An outdoor conduit communicating with the vessel and a valve body are provided, and by moving the valve body, the conduit is selectively communicated to enable switching of the refrigerant flow path. Due to the structure of the four-way valve, high-temperature and high-pressure refrigerant and low-temperature and low-pressure refrigerant flow in the four-way valve at the same time, so heat is transferred from the high-temperature and high-pressure refrigerant to the low-temperature and low-pressure refrigerant via the four-way valve housing. It is known that the cooling capacity and heating capacity of the refrigeration cycle apparatus are reduced, leading to an increase in work volume.

Pipe connection made of material with lower thermal conductivity than copper pipe as a four-way valve to improve the cooling capacity, heating capacity, energy saving performance, etc. of the refrigeration cycle device by suppressing heat transfer between refrigerants in the four-way valve A four-way valve having a portion is disclosed (see Patent Document 1).
Further, a four-way valve is disclosed in which a valve seat into which a conduit is inserted is made of a material having low thermal conductivity (see Patent Document 2). Furthermore, a four-way valve including a heat resistance member made of a material having low thermal conductivity is disclosed between a housing and a valve seat of the four-way valve and a connection pipe (see Patent Document 3).

JP-A-1-314870 Japanese Patent No. 5300657 JP 2009-109062 A

  The invention disclosed in Patent Documents 1 to 3 is a member that can be a heat conduction path between refrigerants in a four-way valve by a material having a lower thermal conductivity than a copper pipe generally used as a refrigerant pipe of a refrigeration cycle apparatus. Therefore, heat transfer is suppressed.

  By the way, in order to suppress heat transfer, the refrigerant flow path in the four-way valve is made of a material having a lower thermal conductivity than copper. Moreover, since it is not preferable that the refrigerant leaks from the refrigerant flow path to the atmosphere, a high barrier property is required for the refrigerant flow path in the four-way valve including the connecting portion. And since most refrigerants used in the refrigeration cycle apparatus always exist in the refrigerant flow path at a pressure higher than atmospheric pressure, the refrigerant flow path in the four-way valve including the connecting portion can maintain pressure resistance. Strength is required.

  However, as the invention disclosed in Patent Documents 1 to 3, a four-way valve that employs a stainless alloy, which is a material satisfying the above conditions, for connection piping or the like is not suitable for brazing joining using phosphor copper brazing that has been conventionally performed. Yes, it was not an invention that considered assembling in the refrigerant flow path of the refrigeration cycle apparatus.

  The present invention solves the above-mentioned problems, provides a four-way valve that suppresses heat transfer in the interior and is considered to be assembled in the refrigerant flow path, and suppresses heat transfer inside the refrigerant flow path. It is an object of the present invention to provide a refrigeration cycle apparatus including a four-way valve in consideration of assembly in

The present invention is applied to an indoor heat exchanger of an indoor unit when applied to a main body, a high-pressure side conduit through which high-temperature and high-pressure fluid flows, a low-pressure side conduit from which low-temperature and low-pressure liquid flows out, and a refrigeration cycle apparatus. and the indoor side of the conduit which communicates, and a outdoor side of the conduit which communicates with the outdoor heat exchanger of the outdoor unit when it is applied to a refrigeration cycle apparatus, and the low pressure side of the conduit, and the indoor side of the conduit, At least one of the outdoor conduits is made of stainless steel or a stainless alloy, and a connection pipe made of a copper alloy is connected to each open end of the low pressure side conduit, the indoor side conduit, and the outdoor conduit. The connecting pipe is connected to each pipe of the refrigeration cycle apparatus by phosphor copper brazing, and when the cross-sectional area of the conduit is A (mm ² ), the low-pressure side conduit and the indoor-side conduit Of the outdoor conduits. The length L1 of the tube consisting of less or stainless alloy is L1 ≧ 0.33A (mm).

The present invention is applied to an indoor heat exchanger of an indoor unit when applied to a main body, a high-pressure side conduit through which high-temperature and high-pressure fluid flows, a low-pressure side conduit from which low-temperature and low-pressure liquid flows out, and a refrigeration cycle apparatus. and the indoor side of the conduit which communicates, and a outdoor side of the conduit which communicates with the outdoor heat exchanger of the outdoor unit when it is applied to a refrigeration cycle apparatus, and the low pressure side of the conduit, and the indoor side of the conduit, at least one of the outdoor side of the conduit is made of stainless steel or stainless steel alloy, the low pressure side of the guide tube, the indoor side of the conduit and the chamber connecting pipe made of copper alloy in the open end of the outer conduit The connecting pipe is connected to each pipe of the refrigeration cycle apparatus by phosphor copper brazing, and when the cross-sectional area of the conduit is A (mm ² ), the low-pressure side conduit, the indoor side Of the conduit and the conduit outside the room, The length L1 of the tube consisting of less or stainless alloy is L1 ≦ 3.3A (mm).

According to the present invention, it is possible to provide a four-way valve that suppresses heat transfer in the interior and is considered to be assembled in the refrigerant flow path, and to suppress the heat transfer in the interior and is considered to be assembled in the refrigerant flow path. A refrigeration cycle apparatus including a valve can be provided.
Problems, configurations, and effects other than those described above will be described in the specification.

It is sectional drawing which shows the operation state at the time of the heating cycle of the four-way valve which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the operation state at the time of the cooling cycle of the four-way valve which concerns on 1st Embodiment of this invention. It is a figure which shows the relationship of the calorie | heat amount which flows into the main body side of the four-way valve with respect to the length of the conduit | pipe of the four-way valve which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the operation state at the time of the heating cycle of the four-way valve which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the operation state at the time of the cooling cycle of the four-way valve which concerns on 2nd Embodiment of this invention. It is a figure of the model used in calculating the temperature distribution of the conduit | pipe of the four-way valve which concerns on 2nd Embodiment of this invention, and the heat exchange amount accompanying it. It is a figure which shows the relationship of the heat transfer amount suppression effect with respect to the length of the conduit | pipe of the four-way valve which concerns on 2nd Embodiment of this invention. It is a figure which shows the temperature of the pipe connection side at the time of brazing of the connection pipe of the four-way valve which concerns on 2nd Embodiment of this invention, and the calculation result of the conduit connection side. It is sectional drawing which shows the operation state at the time of the heating cycle of the four-way valve which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the operation state at the time of the heating cycle of the four-way valve which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the operation state at the time of the heating cycle of the four-way valve which concerns on 5th Embodiment of this invention. It is a figure which shows the operation state at the time of the heating cycle of the refrigerating-cycle apparatus containing the four-way valve which concerns on 2nd Embodiment which concerns on 6th Embodiment of this invention. It is a figure which shows the operation state at the time of a cooling cycle of the refrigerating-cycle apparatus containing the four-way valve which concerns on 2nd Embodiment which concerns on 6th Embodiment of this invention.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate. The present embodiment is not limited to the following contents, and can be implemented with appropriate modifications within the scope of the gist of the present invention, and includes various modifications and application examples.

In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

<First Embodiment>
FIG. 1 is a cross-sectional view showing an operating state during a heating cycle of the four-way valve 1 according to the present embodiment.
As shown in FIG. 1, the four-way valve 1 includes a high-pressure side conduit 11 into which a high-temperature and high-pressure fluid flows, a low-pressure side conduit 12 from which a low-temperature and low-pressure liquid flows out, and an indoor unit when applied to a refrigeration cycle. An indoor conduit 13 communicating with the heat exchanger and an outdoor conduit 14 communicating with the outdoor heat exchanger of the outdoor unit when applied to the refrigeration cycle are respectively connected to the main body 2 of the four-way valve 1. On the opposite side of the circumferential direction of the high pressure side conduit 11, an indoor side conduit 13, a low pressure side conduit 12, and an outdoor side conduit 14 are arranged in this order in the axial direction of the main body 2 of the four-way valve 1. ing. The high-pressure side conduit 11 faces the indoor-side conduit 13 and is arranged in a substantially straight line.

  The four-way valve 1 has a cylindrical metal four-way valve 1 with both ends closed, and a main body 2 of the four-way valve 1 that extends in the axial direction and has a planar seat surface 4a. Metal valve seat 4, resin valve body 3 slidable on the seat surface 4 a of the valve seat 4 along the axial direction, and movable to both sides in the body 2 of the four-way valve 1 Are provided with piston plates 5 and 5 made of metal or resin, and a connecting plate 6 made of metal or resin for connecting the piston plate 5 and the valve body 3.

The main body 2 of the four-way valve 1 is composed of a stainless alloy member (including stainless steel, the same applies hereinafter) composed of a cylindrical tube portion and a disk-like wall portion that closes both ends of the tube portion. Examples of the body 2 of the four-way valve 1 include a four-way valve body having an outer diameter of 28 mm, a thickness of 1 mm, a volume of about 10,000 mm ³ , a density of 7890 kg / m ³ , and a specific heat of 511 J / kg · K.

In the valve seat 4, a chamber communicating with the indoor conduit 13, the low pressure communication passage communicating with the low pressure conduit 12, and the outdoor conduit 14, in order along the axial direction. An outer communication path is formed. The indoor side communication path, the low pressure side communication path, and the outdoor side communication path are each opened in the seat surface 4a.
Examples of the valve seat 4 include a valve seat having a volume of about 3400 mm ³ , a copper alloy (nickel silver, Cu-20Zn-15Ni), a density of 8700 kg / m ³ , and a specific heat of 380 J / kg · K. The valve seat 4 can also be formed of copper, iron, or an iron-based alloy having the same shape.

The valve body 3 has a sliding surface that slides on the seat surface 4a and a recess formed in the sliding surface. Further, the opposite surface side of the sliding surface is formed in a hemispherical shape corresponding to the recess. The opposite hemisphere is formed so as to be spaced from the cylindrical portion of the main body 2 of the four-way valve 1.
The valve body 3 is formed of a resin such as polyphenylene sulfide or nylon.

  A central portion of the connecting plate 6 is fitted and fixed to the valve body 3. Both ends of the connecting plate 6 are fixed to the piston plates 5 and 5. The connecting plate 6 connects the valve body 3 and the piston plates 5 and 5. On the left and right sides of the connecting plate 6, when applied to a refrigeration cycle apparatus, there are communication holes that connect the high-pressure side conduit 11 and the indoor side conduit 13 during heating, and the high-pressure side conduit 11 and the outdoor side during cooling. A communication hole communicating with the conduit 14 is formed. The connecting plate 6 can be formed of, for example, a stainless alloy.

The piston plates 5 and 5 have the same outer peripheral shape as the inner peripheral surface of the wall portion of the main body 2 of the four-way valve 1, and form pressure adjustment spaces at both ends of the main body 2 of the four-way valve 1.
By adjusting the pressure in the pressure adjustment space, the valve element 3 is slid along the axial direction on the seat surface 4a of the valve seat 4 and moved. When the valve body 3 moves, the heating cycle and the cooling cycle of the refrigeration cycle apparatus provided with the four-way valve 1 are switched.
The piston plate 5 is a disc-shaped stainless alloy plate and an outer peripheral portion of the disc-shaped stainless alloy plate, and a sliding portion between the inner peripheral surface of the wall portion of the body 2 of the four-way valve 1 is made of resin (polyphenylene sulfide). Or nylon).

  The valve body 3 is moved in the axial direction on the seat surface 4a, and in a state of being one moving end, the outdoor conduit 14 and the low pressure side conduit 12 are communicated with each other through a valve recess, thereby The refrigerant is circulated from the conduit 14 to the low-pressure side conduit 12 through the valve recess and from the high-pressure side conduit 11 to the indoor side conduit 13 in a substantially straight line. By arranging the high-pressure side conduit 11 and the indoor-side conduit 13 in a substantially straight line in this way, when the four-way valve 1 is applied to a refrigeration cycle, the pressure loss of the high-temperature and high-pressure refrigerant can be reduced. Temperature drop can be suppressed.

  Further, when the refrigerant flow has many disturbances and vortices, the temperature boundary layer between the refrigerant flow and the wall surface of the four-way valve 1 tends to be small due to the disturbance effect, and heat exchange tends to occur. However, by flowing the refrigerant in a substantially straight line as described above, heat exchange with the main body 2 of the four-way valve 1 can be suppressed, and a decrease in the temperature of the refrigerant can also be suppressed.

The high-pressure side conduit 11 is a tube made of a copper alloy (including copper, the same applies hereinafter). Examples of the pipe applicable to the high-pressure side conduit 11 include a copper alloy pipe having an outer diameter of 9.53 mm and a wall thickness of 0.80 mm.
As a stainless alloy tube applicable to the low pressure side conduit 12, the indoor side conduit 13, and the outdoor side conduit 14, for example, a stainless alloy tube having an outer diameter of 12.7 mm and a wall thickness of 0.80 mm is used. Can be mentioned.

  In this embodiment, in order to suppress the heat transfer from the high-temperature refrigerant to the low-temperature refrigerant inside the four-way valve 1 as much as possible, the main body 2 of the cylindrical (cylindrical) four-way valve 1, the low pressure side conduit 12, the indoor side The conduit 13 and the outdoor conduit 14 are made of stainless steel alloy. The stainless steel alloy used in this embodiment is an alloy containing iron (Fe) as a main component and containing 10.5% or more of chromium (Cr). The stainless steel alloy used in this embodiment may further contain elements such as nickel (Ni), manganese (Mn), and molybdenum (Mo) in addition to iron and chromium.

  When the four-way valve 1 is applied to a refrigeration cycle, it is discharged from the compressor 102 (see FIG. 12) due to two effects obtained by arranging the high-pressure side conduit 11 and the indoor-side conduit 13 in a substantially straight line. Therefore, the performance of the refrigeration cycle during heating can be improved by applying the four-way valve 1 because the energy loss of the refrigerant can be suppressed as much as possible and can be distributed to the indoor heat exchanger 112 of the indoor unit 110.

  When the four-way valve 1 is applied to a refrigeration cycle apparatus, a high-pressure refrigerant always flows through the high-pressure side conduit 11 of the four-way valve 1 during a heating cycle and a cooling cycle, and a low-pressure refrigerant always flows through the low-pressure side conduit 12. Flows. A high pressure refrigerant flows outside the valve body 3, and a low pressure refrigerant flows inside the valve body 3, thereby creating a pressure difference between the outside and inside of the valve body 3, so that the valve body 3 is always in the valve seat 4. Receives pressing force.

FIG. 2 is a cross-sectional view showing an operating state during the cooling cycle of the four-way valve 1 according to the present embodiment.
In the state where the valve body 3 is moved in the axial direction on the seat surface 4a and used as the other moving end, the indoor side conduit 13 and the low pressure side conduit 12 are communicated with each other via the valve recess. The refrigerant is circulated from the conduit 13 to the low pressure side conduit 12 through the recess of the valve, and through the space formed by the outer surface of the valve body 3 and the inner surface of the main body 2 of the four-way valve 1 from the high pressure side conduit 11. Then, the refrigerant is circulated through the conduit 14 outside the room.

  Next, calculation of the shortest lengths of the high pressure side conduit 11, the low pressure side conduit 12, the indoor side conduit 13, and the outdoor side conduit 14 will be described. In this embodiment, the length L1 of the conduit is the distance from the connection portion of the four-way valve 1 with the main body 2 to the open end of the conduit.

The valve body 3 existing inside the four-way valve 1 is formed of a resin such as polyphenylene sulfide or nylon. The valve body 3 may be deformed when heated to a temperature equal to or higher than the glass transition point. And when the valve body 3 deform | transforms, the sealing performance (airtightness) of the valve body 3 may fall. In order to prevent the deformation of the valve body 3, the temperature of the metal around the valve body 3 is lower than the glass transition point of the valve body 3 when the conduit and the piping of the refrigerant cycle are joined. Incidentally, the glass transition point of nylon is 88 ° C.
Therefore, the amount of heat flowing from the conduit to the main body 2 of the four-way valve 1 relative to the length of the stainless steel conduit was calculated.

  The valve seat 4 that conducts heat to the valve body 3 based on the volume of the main body 2, the valve seat 4, the piston plate 5 and the connecting plate 6 of the four-way valve, and the density and specific heat of the stainless alloy or copper alloy that is the metal used for these. The amount of heat required for the metal such as the body 2 of the four-way valve to reach the glass transition temperature (88 ° C.) of the valve body 3 from 25 ° C. is required. When calculated for the four-way valve 1 of the present embodiment, this amount of heat is about 3300 J.

  FIG. 3 shows the relationship between the amount of heat flowing into the main body side of the four-way valve 1 with respect to the length of the conduit, and shows the amount of heat flowing into the main body 2 of the four-way valve from the connection pipe in 90 seconds in consideration of the brazing operation.

As shown in FIG. 3, when the length of the conduit is 10 mm or less, the amount of heat flowing into the main body 2 of the four-way valve 1 reaches about 3300 J reaching the glass transition point of the valve body 3 (causing softening).
Therefore, in consideration of the joining of the conduit and the piping of the refrigerant cycle by brazing, the length of the stainless alloy conduit needs to be 10 mm or more.

  The assumed condition in the calculation is a condition assuming a four-way valve applied to a home air conditioner, and the amount of heat that causes softening of the valve body 3 varies depending on the mass of the metal constituting the four-way valve. 3300J can be used as a reference.

  Therefore, when joining the pipe | tube of a refrigerating cycle apparatus etc. to the conduit | pipe of the four-way valve in the said assumption conditions by brazing, protection of the valve body 3 is achieved by making the length L1 of a conduit | pipe into 10 mm or more.

  And the case where the valve body 3, the valve seat 4, the conduit | pipe 12, etc. are changed is demonstrated.

  Unlike the assumed conditions, when the valve body 3 and the valve seat 4 are formed of a metal having a low density or an alloy having a different composition, and when the mass of the valve body 3 and the valve seat 4 is increased, The volume of the valve body 3 and the valve seat 4 may become large. When the volume of the valve seat 4 or the like increases, the contact area between the valve body 3 and the valve seat 4 increases, and thus heat transfer from the conduit 12 or the like to the valve body 3 by heat conduction is promoted. That is, the effect of suppressing heat conduction is reduced, and the cooling / heating performance is reduced.

  On the other hand, unlike the above assumed conditions, when the valve body 3 and the valve seat 4 are formed of a metal having a high density or an alloy having a different composition, and when the mass of the valve body 3 and the valve seat 4 is reduced. The volume of the valve body 3 and the valve seat 4 may be reduced. When the volume of the valve seat 4 or the like is reduced, the contact area between the valve body 3 and the valve seat 4 is reduced, so that heat transfer from the conduit 12 or the like to the valve body 3 due to heat conduction is suppressed. That is, the effect of suppressing heat conduction is increased, and the performance of cooling and heating is improved.

The conduits 12, 13, and 14 connected to the valve seat 4 serve as fins. For this reason, when the conduit | pipe 12 grade | etc., Is formed with the material of an alloy composition and density different from the said assumption, thermal conductivity may change. When the thermal conductivity of the conduit 12 and the like is improved, heat transfer from the conduit to the valve body 3 is promoted. That is, the effect of suppressing heat conduction is reduced, and the cooling / heating performance is reduced. When the thermal conductivity of the conduit 12 or the like decreases, the heat transfer from the conduit to the valve body 3 is suppressed. That is, the effect of suppressing heat conduction is increased, and the performance of cooling and heating is improved.
In order to suppress heat transfer from the conduit 12 or the like to the valve body 3 due to heat conduction, the conduit 12 or the like may be lengthened.

  Furthermore, the case where the outer diameter and thickness of a conduit | pipe differ is demonstrated.

When the outer diameter of the conduit is defined as D (mm), the thickness of the conduit is defined as t (mm), and the cross-sectional area is defined as A (mm ² ), the following formula 1 is established.

Similarly, if the outer diameter of the conduit under the above-mentioned assumptions is defined as D ₀ (mm), the thickness of the conduit is defined as t ₀ (mm), and the cross-sectional area is defined as A ₀ (mm ² ), the following formula 2 is established.

  Therefore, the heat capacity of the main body 2 of the four-way valve 1 and the assumed conditions of the valve body 3 are the same, and the length L1 of the conduit when the outer diameter and thickness of the conduit are different is expressed by the following equation (3).

From the above, if the piping of the refrigeration cycle apparatus to the conduit of the four-way valve is joined by brazing, by setting the length L1 of the conduit _{0.33A (= 10A / A 0)} (mm) or more, the valve body 3 As a result, it is possible to assemble the four-way valve 1 and to improve workability.

Second Embodiment
The second embodiment is an embodiment in which the connection pipe 21 is connected to each of the low pressure side conduit 12, the indoor side conduit 13, and the outdoor side conduit 14 in the four-way valve 1 of the first embodiment. is there. In the present embodiment, a connecting pipe 21 having an inner diameter expanded beyond the outer diameter of the open end of the conduit is connected to the open end of the conduit.

  FIG. 4 is a cross-sectional view showing the operating state of the four-way valve 1A according to the present embodiment during the heating cycle. FIG. 5 is a cross-sectional view showing an operating state during the cooling cycle of the four-way valve 1A according to the present embodiment. By using the connecting pipe 21, heat transfer from the high-temperature refrigerant to the low-temperature refrigerant is suppressed as much as possible inside the four-way valve 1A.

Calculation of the lengths of the low-pressure side conduit 12, the indoor-side conduit 13, and the outdoor-side conduit 14 in the present embodiment will be described.
In calculating the lengths of these conduits, a four-way valve 1A shown in FIG. 4 was assumed. FIG. 6 shows the model used in calculating the temperature distribution of the conduit and the amount of heat exchange associated therewith. In the present embodiment, unlike the first embodiment, the length L1 of the conduit is the distance from the connection portion of the four-way valve 1 to the main body 2 to the end of the connection pipe 21.

In calculating the lengths of these pipes, the temperature at the upper end of the pipe has a temperature difference of θ ₀ K from the refrigerant mainstream temperature, and the thermal conductivity h (W / (m ² · K)) on the pipe inner surface. It is assumed that heat exchange is performed with the refrigerant. The temperature change on the refrigerant side is ignored because the refrigerant circulation amount is large and the temperature change is small.

When the outer diameter of the conduit is defined as D (mm) and the wall thickness is defined as t (mm), the cross-sectional area S (mm ² ) of the conduit and the length L (mm) of the wetting edge are expressed by the following equations 4, 5 is obtained.

  Here, if it is assumed that the temperature change in the longitudinal direction of the conduit is equal to the amount of heat exchange with the refrigerant, the following differential equation (6) is obtained.

  Similarly, a differential equation is established on the connecting pipe side, and each solution is assumed as follows.

Here, m _SUS and m _Cu are as follows.

Here, from the boundary condition, the temperature is θ _{0 at the} top of the conduit,

  Also, at the joint between the conduit and the connecting pipe, the temperature is the same and the amount of heat transfer is the same.

  Further, assuming that there is no heat transfer at the lower end of the connecting pipe, the following equation 14 holds.

  From these, the constants C1, C2, C3, and C4 are obtained as follows.

  Using this solution (C1, C2, C3, C4), the temperature distribution of the conduit is obtained, and the amount of heat transfer from the conduit to the refrigerant is obtained by multiplying the obtained temperature distribution of the conduit by the area inside the conduit and the thermal conductivity. It is done. This heat transfer amount becomes smaller as the stainless alloy tube is longer. Therefore, when the length of the conduit is zero, the heat transfer rate is 0%, and when the length of the conduit is 200 mm, the heat transfer rate is 100%. As a percentage, the relationship between the length of the conduit and the heat transfer inhibition rate was calculated. The result is shown in FIG.

FIG. 7 shows the relationship between the heat transfer amount suppression effect and the length of the conduit.
As shown in FIG. 7, the longer the conduit, the higher the effect of suppressing the amount of heat transfer. Further, when the heat transfer coefficient inside the conduit is increased, the effect of suppressing the amount of heat transfer is saturated at a shorter point.

The refrigerant flowing into the four-way valve is in a state close to a gas single phase, and its heat transfer coefficient is estimated to be 10 W / (m ² · K) or more and less than 1000 W / (m ² · K). Considering the temperature change of the refrigerant due to heat transfer, in the actual four-way valve 1A, the amount of heat released from the inner surface of the conduit is smaller than that of the current model, so the temperature distribution of the conduit has a low heat transfer rate. Presumed to approach.
Even if these are taken into consideration, the heat conduction suppressing effect can be sufficiently obtained if the length of the conduit is about 100 mm from FIG.

Then, connection between the four-way valve 1A according to the present embodiment and the piping of the refrigeration cycle apparatus will be described.
When assembling refrigeration cycle equipment, when connecting parts such as heat exchangers, compressors, accumulators and four-way valves to pipes, copper alloy pipes are often used for the pipes and pipes of each part. Generally, phosphor copper brazing is used. Phosphor copper brazing is possible without the need for flux in joining copper alloys, and the working efficiency of joining is improved. Moreover, the use of phosphor copper brazing eliminates the need for flux preparation and management, leading to cost reduction. For this reason, it is general that the assembly operation of the refrigeration cycle apparatus is performed consistently using only phosphorous copper solder.

  However, since the four-way valve 1A according to this embodiment employs a stainless alloy pipe as a conduit, the material is different from each copper alloy pipe of the refrigeration cycle apparatus, and the four-way valve 1A and each pipe are joined differently. It becomes metal bonding. In joining stainless steel pipes and copper alloy pipes, joining using phosphor copper brazing has problems in terms of reliability, such as strength, so silver brazing, copper and copper alloy brazing in a furnace, nickel brazing, etc. It is common to perform joining by brazing.

In this embodiment, the connection pipe 21 made of copper alloy is provided at the tip of each conduit 12, 13, 14 of the four-way valve 1A, so that the four-way valve 1A and each pipe (not shown) are connected via the connection pipe 21. Connection is made, and the connecting pipe 21 and each pipe are joined using phosphor copper brazing.
When the connecting pipe 21 is heated by a gas burner in the joining of the connecting pipe 21 using phosphor copper brazing and each pipe of the refrigeration cycle apparatus, the connecting portion of each pipe of the four-way valve 1A above the connecting pipe 21 is also thermally conductive. Heated.
Therefore, appropriate lengths of the respective conduits 12, 13, and 14 of the four-way valve 1A were obtained.

  Assuming that phosphor copper brazing (BCuP-2) is used in joining the connecting pipe 21 and the piping of the refrigeration cycle apparatus, the temperature of the connecting pipe 21 on the piping side of the refrigeration cycle apparatus is 845 ° C. The temperature of the connection portion of the four-way valve 1A with the conduit was assumed to be 25 ° C. The length of the connecting tube 21 was assumed to be 35 mm, the outer diameter 12.7 mm, and the wall thickness 0.80 mm.

  Based on this assumption, the temperature on the pipe connection side (lower end side in the figure) at the time of brazing of the connection pipe 21 and the temperature on the conduit connection side (upper end side in the figure) were calculated from the balance of thermal resistance. This calculation result is shown in FIG. 8 as a graph of the obtained temperature relationship. As shown in FIG. 8, when the conduit made of stainless alloy is lengthened, the temperature on the conduit connection side of the connection pipe rises.

  Assuming that the conduit connection side and the conduit are brazed with copper brazing (BCu-4) at the upper part of the connecting pipe 21, the length of the conduit that becomes less than 830 ° C., which is the minimum melting temperature of the copper brazing, is shown in FIG. 8 is 100 mm or less. That is, by setting the length of the stainless alloy conduit to 100 mm or less, it is easy to braze the connecting pipe 21 and the copper alloy pipe with phosphor copper brazing.

  In this embodiment, examples of usable phosphor copper solder include BCuP-1, BCuP-3, BCuP-4, BCuP-5, and BCuP-6 (JIS Z 3264: 1998) in addition to BCuP-2. Can be mentioned. In this embodiment, examples of usable copper and copper alloy brazing include BCu-1, BCuP-1A, BCu-2, and BCu-3 (JIS Z 3262: 1998) in addition to BCu-4. .

  Up to now, the case of a conduit having an outer diameter of 12.7 mm and a wall thickness of 0.80 mm has been described in accordance with the above-mentioned assumptions. Further, a case where the outer diameter and thickness of the conduit are different will be described.

Similarly to the first embodiment, when the outer diameter of the conduit is defined as D (mm), the thickness of the conduit is defined as t (mm), and the cross-sectional area is defined as A (mm ² ), the following Expression 1 is established.

Similarly, if the outer diameter of the conduit under the above-mentioned assumptions is defined as D ₀ (mm), the thickness of the conduit is defined as t ₀ (mm), and the cross-sectional area is defined as A ₀ (mm ² ), the following formula 2 is established.

  Therefore, the heat capacity of the main body 2 of the four-way valve 1 and the assumed conditions of the valve body 3 are the same, and the length L1 of the conduit when the outer diameter and thickness of the conduit are different is expressed by the following equation (22).

From the above, when the piping of the refrigeration cycle apparatus is joined to the conduit of the four-way valve via the connection tube 21 by brazing, the length L1 of the conduit is 3.3 A (= 100 A / A ₀ ) (mm) or less. This facilitates protection of the brazed portion between the conduit and the connecting tube 21. As a result, assembly workability is improved.

  In addition, the length of the connecting pipe 21 will be described.

When the length is L (mm), the cross-sectional area is A (mm ² ), and the thermal conductivity is λ (W / mK), the thermal resistance R ((mm · mK) / W) is expressed by the following Equation 23. It is.

Assuming that the conduit in this embodiment has a length L = 100 (mm), a cross-sectional area A = 29.91 (mm ² ), and a thermal conductivity λ = 18 (W / mK), from Equation 23, the conduit Is expressed by the following equation 24.

Assuming that the connecting pipe in this embodiment has a length L = 35 (mm), a cross-sectional area A = 29.91 (mm ² ), and a thermal conductivity λ = 320 (W / mK), Equation 23 Thus, the thermal resistance of the connecting pipe is expressed by the following formula 25.

In the connecting pipe 21, the temperature on the piping side of the refrigeration cycle apparatus is 845 ° C., the temperature on the conduit side is x ° C., and in the conduit, the temperature on the connecting pipe side is x ° C., and the temperature on the main body 2 side of the four-way valve 1 is In order to establish the relationship of 25 ° C., it is necessary to balance the amount of heat flowing through the connecting pipe 21 with the amount of heat flowing through the conduit.
That is, the relationship of the following formula is established.

  Therefore, the temperature x on the conduit side of the connecting pipe 21 is expressed by the following equation. The conduit side temperature x should be lower than 830 ° C.

Organizing the formula

  Therefore, it is sufficient to satisfy the relationship of the following expression 29.

  For example, assuming that the thermal conductivity of the copper alloy connecting tube is 320 W / mK, the thermal conductivity of the stainless steel conduit is 18 W / mK, and the cross-sectional area of the tube is the same, As shown in FIGS. 4 and 5, the length L2 of the connecting pipe may be set to 1/3 times or less of the length L1 of the conduit. Even when the cross-sectional area of the connecting pipe 21 is different from that of the conduit, or even when the connecting pipe 21 is different from the assumed condition, the length L2 of the connecting pipe can be obtained similarly.

  From the above, when the brazing joint of the refrigeration cycle apparatus is connected to the four-way valve conduit via the connecting pipe by phosphor copper brazing, the length L1 of the conduit is set to 3.3 A (mm) or less. As a result, it becomes easy to protect the brazed portion between the connecting pipe 21 and the connecting pipe 21, and the assembling workability is improved. By setting the length L2 of the connecting pipe to 1/3 times or less of the length L1 of the conduit, the brazed portion between the conduit and the connecting tube 21 can be easily protected, and the assembling workability is improved.

<Third Embodiment>
The third embodiment is an implementation in which the conduit is expanded at the joint between the conduit and the connecting pipe in the four-way valve 1 of the first embodiment so that the piping of the refrigeration cycle and the connecting pipe 21 are inserted into the conduit. It is a form.

FIG. 9 is a cross-sectional view showing the operating state of the four-way valve 1B according to the present embodiment during the heating cycle.
Of the low-pressure side conduit 12B, the indoor side conduit 13B, and the outdoor side conduit 14B below the four-way valve 1, low-temperature and low-pressure refrigerant flows through the low-pressure side conduit 12 and the remaining one conduit. Since the temperature of the conduit through which the low-temperature and low-pressure refrigerant flows may be lower than the outside air, condensation may occur outside the conduit.

The droplets generated by the condensation hang down below the conduit and are held by the surface tension at the step between the conduit and the connecting tube 21 (the step on the outer periphery of the tube). The area of the metal in contact with the retained droplets increases on the connecting tube 21 side. Since the connection pipe 21 made of copper alloy has higher corrosion resistance than a conduit made of stainless alloy, the corrosion resistance of the main body 2 of the four-way valve 1 can be improved by adopting a structure in which the connection pipe 21 is inserted into the conduit. .
The same effect can be obtained even when a copper alloy refrigeration cycle pipe is connected instead of the copper alloy connection pipe 21.

<Fourth embodiment>
The fourth embodiment is an embodiment in which copper plating is applied to the inner peripheral portion of the open end of the conduit at the joint between the conduit and the connecting pipe in the four-way valve 1 of the third embodiment.

FIG. 10 is a cross-sectional view showing the operating state of the four-way valve 1C according to the present embodiment during the heating cycle.
As shown in FIG. 10, the range of copper plating applied to the open ends of the low pressure side conduit 12C, the indoor conduit 13C, and the outdoor conduit 14C at the bottom of the four-way valve is at least within the open ends of these conduits. It is a circumference and it is set as the range which can ensure joining strength with piping of a refrigerating cycle, or connecting pipe 21.

  Copper plating is also preferably applied to the cross-sectional portions of the open ends of these conduits. Even if the copper plating is applied to the cross-section, and the droplets generated by condensation on the surface of these conduits hang down and are held at the step portion of the joint with the piping of the refrigeration cycle apparatus, these conduits Corrosion resistance can be improved.

  By applying copper plating to the inner periphery of the open ends of these conduits, the pipes and connecting pipes 21 of the refrigeration cycle expanded by phosphorous copper braze (BCuP-2) or the like instead of brazing in the furnace are joined to these conduits. Can do.

<Fifth Embodiment>
The fifth embodiment is an embodiment in which copper plating is applied to the outer periphery of the open end of the low pressure side conduit 12, the indoor side conduit 13, and the outdoor side conduit 14 of the four-way valve 1 of the first embodiment. is there.

FIG. 11 is a cross-sectional view showing an operating state during the heating cycle of the four-way valve 1D according to the present embodiment.
As shown in FIG. 11, the range of copper plating applied to the open ends of the low pressure side conduit 12D, the indoor side conduit 13D, and the outdoor side conduit 14D at the bottom of the four-way valve is at least the outer circumference of the open ends of these conduits. It is a part, Comprising: It is set as the range which can ensure the joint strength with the piping of the refrigerating cycle, or the connecting pipe 21. The amount of copper plating is an amount that can secure the bonding strength with the piping of the refrigeration cycle apparatus.

  By applying copper plating to the outer periphery of the open ends of these conduits, it is possible to join the pipes and connecting pipes 21 of the refrigeration cycle expanded not by brazing in the furnace but by phosphorous copper brazing (BCuP-2) or the like to these conduits. it can.

<Sixth Embodiment>
The sixth embodiment is a refrigeration cycle apparatus including the four-way valve of the first to fifth embodiments as a constituent element.
FIG. 12 shows, as an example, a refrigeration cycle apparatus including the four-way valve 1A of the second embodiment in a heating cycle state.

  The refrigeration cycle apparatus according to the present embodiment includes a four-way valve 1A inside the outdoor unit 101, a compressor 102, an expansion valve 103, an outdoor heat exchanger 104, an outdoor fan 105, and an accumulator 106, and includes a room inside the indoor unit 110. The heat exchanger 111 and the indoor fan 112 are connected by piping.

  The compressor 102 compresses the low-temperature and low-pressure gas refrigerant, and discharges the high-temperature and high-pressure gas refrigerant to the four-way valve 1A. The high-temperature and high-pressure gas refrigerant discharged from the compressor 102 flows into the four-way valve 1A from the high-pressure side conduit 11 of the four-way valve 1A.

  In the four-way valve 1A, as shown in FIG. 12, the valve body 3 is present at a position where the high-pressure side conduit 11 and the indoor side conduit 13 communicate with each other. The high-temperature and high-pressure gas refrigerant that has flowed into the four-way valve 1A passes through the inside of the four-way valve 1A and flows out from the indoor conduit 13.

  The high-temperature and high-pressure gas flowing out of the four-way valve 1A reaches the indoor heat exchanger 111. The high-temperature and high-pressure gas that has reached the indoor heat exchanger 111 passes the thermal energy to the air taken into the indoor unit 110 by the indoor fan 112 and warms it. The gas refrigerant that has lost its heat energy condenses and becomes a liquid refrigerant in a low-temperature and high-pressure state. The warmed air is supplied indoors as warm air by the indoor fan 112.

The low-temperature and high-pressure liquid refrigerant condensed in the indoor heat exchanger 111 flows out to the expansion valve 103.
The expansion valve 103 is a pressure regulating valve that can change the fluid resistance. The low-temperature and high-pressure liquid refrigerant that has flowed into the expansion valve 103 is depressurized and reduced in temperature to become a gas-liquid mixed phase two-phase flow. The low-temperature and low-pressure two-phase refrigerant flows into the outdoor heat exchanger 104.

The outdoor fan 105 blows external air having a temperature higher than that of the refrigerant flowing into the outdoor heat exchanger 104. The low-temperature, low-pressure two-phase flow refrigerant that has flowed into the outdoor heat exchanger 104 receives heat energy from the external air, and the liquid phase evaporates to become a gas refrigerant.
The low-temperature and low-pressure gas refrigerant gasified in the outdoor heat exchanger 104 flows into the four-way valve 1A again.

  In the four-way valve 1A, the valve body 3 is present at a position where the outdoor conduit 14 and the low pressure conduit 12 communicate with each other. For this reason, the low-temperature and low-pressure gas refrigerant flowing into the four-way valve 1 </ b> A flows into the accumulator 106.

The accumulator 106 has a function of limiting the flow rate so that a large amount of low-temperature and low-pressure gas refrigerant does not flow into the compressor 102 at a time.
The low-temperature and low-pressure gas refrigerant that has flowed out of the accumulator 106 flows into the compressor 102. The low-temperature and low-pressure gas refrigerant flowing into the compressor 102 is compressed and circulates through the refrigeration cycle again.

  FIG. 13 shows, as an example, a refrigeration cycle apparatus including the four-way valve 1A of the second embodiment in the cooling cycle state. A different point from a heating cycle is demonstrated.

  In the four-way valve 1A in the cooling cycle state, the valve body 3 is present at a position where the high pressure side conduit 11 and the outdoor side conduit 14 communicate with each other. The high-temperature and high-pressure gas refrigerant flowing into the four-way valve 1A from the compressor 102 flows out to the outdoor heat exchanger 104.

  The high-temperature and high-pressure gas refrigerant flowing into the outdoor heat exchanger 104 is cooled and liquefied by passing thermal energy to the external air blown by the outdoor fan 105.

  The low-temperature and high-pressure liquid refrigerant flowing out of the outdoor heat exchanger 104 reaches the indoor heat exchanger 111, receives heat energy from the air taken into the interior of the indoor unit 110 by the indoor fan 112, evaporates, and evaporates at high temperature and pressure. It becomes a state gas refrigerant.

<Modification>
As shown in the first to fifth embodiments, one or two of the low-pressure side conduit 12, the indoor-side conduit 13, and the outdoor-side conduit 14 at the lower part of the four-way valve 1 are used more than the others. For example, the brazing position can be shifted by making the length of the low-pressure side conduit 12 arranged in the center longer than the indoor-side conduit 13 and the outdoor-side conduit 14 arranged on the left and right. For this reason, the brazing operation becomes easy.
The lengths of the low-pressure side conduit 12, the indoor-side conduit 13, and the outdoor-side conduit 14 below the four-way valve 1 may all be the same or different.

  The four-way valve according to the present invention is, for example, both a four-way valve that does not include the connecting pipe 21 shown as the first embodiment and a four-way valve that uses the connecting pipe 21 shown as the second embodiment as a constituent element. Includes a four-way valve.

1, 1A, 1B, 1C, 1D Four-way valve 2 Main body 3 Valve 4 Valve seat 4a Seat surface 5 Piston plate 6 Connecting plate 11 Conduit 12, 12B, 12C, 12D Conduit 13, 13B, 13C, 12D Conduit 14, 14B, 14C 12D Conduit 21 Connecting pipe 51 Refrigerant flow direction 52 Refrigerant flow direction 53 Refrigerant flow direction 54 Refrigerant flow direction 61 Refrigerant flow direction 62 Refrigerant flow direction 63 Refrigerant flow direction 64 Refrigerant flow direction
71 Copper plating
101 outdoor unit
102 Compressor
103 expansion valve
104 Outdoor heat exchanger
105 Accumulator
106 Outdoor fan
110 Indoor unit
111 Indoor heat exchanger
112 Indoor fan

Claims (9)

A main body, a high-pressure side conduit through which high-temperature and high-pressure fluid flows, a low-pressure side conduit through which low-temperature and low-pressure liquid flows out, and an indoor side that communicates with the indoor heat exchanger of the indoor unit when applied to a refrigeration cycle apparatus And an outdoor conduit communicating with the outdoor heat exchanger of the outdoor unit when applied to the refrigeration cycle apparatus,
And the low pressure side of the conduit, and the indoor side of the conduit, at least one of the outdoor side of the conduit is made of stainless steel or stainless steel alloy,
A connection pipe made of a copper alloy is connected to each open end of the low-pressure side conduit, the indoor-side conduit, and the outdoor-side conduit,
The connection pipe is connected to each pipe of the refrigeration cycle apparatus by a phosphor copper braze,
When the cross-sectional area of the conduit is A (mm ² ),
Of the low-pressure side conduit, the indoor-side conduit, and the outdoor-side conduit, the length L1 of a tube made of stainless steel or a stainless alloy is L1 ≧ 0.33 A (mm). A main body, a high-pressure side conduit through which high-temperature and high-pressure fluid flows, a low-pressure side conduit through which low-temperature and low-pressure liquid flows out, and an indoor side that communicates with the indoor heat exchanger of the indoor unit when applied to a refrigeration cycle apparatus And an outdoor conduit communicating with the outdoor heat exchanger of the outdoor unit when applied to the refrigeration cycle apparatus ,
And the low pressure side of the conduit, and the indoor side of the conduit, at least one of the outdoor side of the conduit is made of stainless steel or stainless steel alloy,
The low pressure side of the guide tube, the connection pipe made of a copper alloy is connected to the indoor side of the conduit and the open end of the chamber outside the conduit,
The connection pipe is connected to each pipe of the refrigeration cycle apparatus by a phosphor copper braze,
When the cross-sectional area of the conduit is A (mm ² ),
A length L1 of a pipe made of stainless steel or a stainless alloy among the low-pressure side conduit, the indoor-side conduit, and the outdoor-side conduit is L1 ≦ 3.3A (mm). A main body, a high-pressure side conduit through which high-temperature and high-pressure fluid flows, a low-pressure side conduit through which low-temperature and low-pressure liquid flows out, and an indoor side that communicates with the indoor heat exchanger of the indoor unit when applied to a refrigeration cycle apparatus And an outdoor conduit communicating with the outdoor heat exchanger of the outdoor unit when applied to the refrigeration cycle apparatus ,
At least one of the low-pressure side conduit, the indoor-side conduit, and the outdoor-side conduit is made of stainless steel or a stainless alloy,
The low pressure side of the guide tube, the connection pipe made of a copper alloy is connected to the indoor side of the conduit and the open end of the chamber outside the conduit,
The connection pipe is connected to each pipe of the refrigeration cycle apparatus by a phosphor copper braze,
The four-way valve, wherein a length L2 of the connecting pipe with respect to a length L1 of the conduit is 1/3 or less. The four-way valve according to any one of claims 1 to 3, wherein the connection pipe has an inner diameter that is larger than an outer diameter of an open end of the conduit and is connected to the conduit. The inner diameter of the said open end is expanded more than the outer diameter of a connection pipe, and the said connection pipe is inserted in the open end where the said pipe was expanded . The four-way valve according to one item . The conduit is an outer peripheral surface of the open end, either side of the inner peripheral surface, or square according to any one of claims 1-5 in which both surfaces is characterized in that it is copper-plated valve. The four-way valve according to any one of claims 1 to 6 , wherein the conduit and the connection pipe are joined by a brazing material having a melting point higher than that of the phosphor copper brazing.   The four-way valve according to any one of claims 1 to 7, wherein the low-pressure side conduit is longer than one of the indoor-side conduit, the outdoor-side conduit, or both. A compressor that compresses the refrigerant, the first heat exchanger, the decompression means, and the second heat exchanger are formed by connecting the second heat exchanger in a ring shape with a refrigerant pipe, and a refrigeration cycle filled with the refrigerant is formed. And
The four-way valve according to any one of claims 1 to 8 is disposed in the refrigerant pipe,
Of the first heat exchanger and the second heat exchanger, one heat exchanger is in communication with the discharge port of the compressor, and the other heat exchanger is in communication with the suction port of the compressor. A refrigeration cycle apparatus characterized in that the refrigerant flow path can be selectively switched so that

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