CN101033805A - Expansion valve - Google Patents

Abstract

A thermostatic expansion valve 3 is applied to a refrigeration cycle having an internal heat exchanger 5 for heat exchange between high-temperature refrigerant flowing from a condenser 2 to the expansion valve 3 and low-temperature refrigerant flowing from an evaporator 4 2 via the expansion valve 3 to a compressor. The expansion valve 3 comprises a bypass passage 3a or 3b for guiding refrigerant either from a high-pressure refrigerant inlet or a low-pressure refrigerant outlet to the downstream side of a temperature-sensing section, such that moist refrigerant is mixed with refrigerant whose degree of superheat is controlled by the expansion valve 3. This lowers the temperature of refrigerant that is drawn into the compressor 1.To provide an expansion valve which is capable of preventing the temperature of refrigerant compressed by a compressor from becoming too high, when a refrigeration load on a refrigeration cycle using an internal heat exchanger is high. A thermostatic expansion valve is applied to a refrigeration cycle provided with an internal heat exchanger that performs heat exchange between high-temperature refrigerant flowing from a condenser to the expansion valve and low-temperature refrigerant flowing from an evaporator to a compressor via the expansion valve. The expansion valve comprises a bypass passage or for causing refrigerant in a high-pressure refrigerant inlet or a low-pressure refrigerant outlet to flow to the downstream side of a temperature-sensing section, such that moist refrigerant is mixed with refrigerant whose degree of superheat is controlled by the expansion valve. This lowers the temperature of refrigerant that is drawn into the compressor when refrigeration load is high is lowered, to thereby prevent the temperature of refrigerant compressed by the compressor from becoming too high.

Description

Expansion valve

Technical field

The present invention relates to a kind of expansion valve, relate more specifically to a kind of thermostatic expansion valve, this thermostatic expansion valve is according to the temperature and pressure in the outlet port of the vaporizer in the refrigeration cycle of air conditioner for automobile, controls the flow velocity of the refrigeration agent of waiting to be supplied to vaporizer.

Background technique

From angle, proposed to use carbon dioxide substitute CFC substitute (HFC-134a) to be used as being used for the refrigeration agent of the refrigeration cycle of air conditioner for automobile about the environmental problem of global warming.In the cooling cycle system that utilizes carbon dioxide as refrigeration agent,, use internal exchanger (for example seeing TOHKEMY 2001-108308 communique) usually in order to raise the efficiency.

Internal exchanger is configured to like this, that is, carry out heat exchange at the refrigeration agent in the path that extends to expansion valve from gas cooler (its cooling compressed high-temperature high-pressure refrigerant) of flowing through and between the refrigeration agent in the path that extends to compressor from trap of flowing through by compressor.By this structure, overheated from the vapor phase refrigerant that trap is extracted out by the refrigeration agent in the path on the high pressure side of the internal exchanger of flowing through, be transported to compressor then.This makes compressor can suck drying cryogen, therefore operation effectively.

By contrast, in using the refrigeration cycle of HFC-134a, attempt to adopt the system that is combined with internal exchanger equally as refrigeration agent.Expect that the efficient of this system also is improved.

Yet, in using the refrigeration cycle of HFC-134a, use thermostatic expansion valve usually as expansion valve as refrigeration agent.The refrigeration agent at thermostatic expansion valve control evaporator outlet place makes it have predetermined degree of superheat.The result, the refrigeration cycle that is provided with internal exchanger (carrying out heat exchange between the refrigeration agent in the refrigeration agent in making is flowing through extends to expansion valve from condenser path and the path that extends to compressor from vaporizer of flowing through), the refrigeration agent overheated in the outlet port of vaporizer is further overheated by internal exchanger, be delivered to compressor then, thereby occur by become Tai Gao so that of the temperature of compressor refrigerant compressed owing to high temperature makes the problem of the deterioration of lubricant in the compressor, especially all the more so when refrigeration cycle is moved under the higher state of cooling load.

Summary of the invention

The present invention considers that above problem makes, and its purpose is to provide a kind of expansion valve, and this expansion valve can prevent from by the cooling load of the temperature of compressor refrigerant compressed on the refrigeration cycle of using internal exchanger to become too high when higher.

In order to address the above problem, according to the present invention, a kind of thermostatic expansion valve is provided, this thermostatic expansion valve is configured to by making temperature sensing portion sensing control the flow velocity of the refrigeration agent that is delivered to vaporizer from the temperature and pressure of the refrigeration agent of vaporizer outflow, this thermostatic expansion valve comprises bypass channel, this bypass channel is formed between high-pressure refrigerant inlet or low pressure refrigerant outlet and the coolant channel, be used to make high pressure liquid refrigerant or low-pressure gas-liquid mix refrigerant to flow to the downstream side of described temperature sensing portion, wherein high-pressure refrigerant is supplied to described high-pressure refrigerant inlet, low pressure refrigerant is delivered to described vaporizer from described low pressure refrigerant outlet, and described coolant channel passes through the described refrigeration agent that flows out from described vaporizer.

When combination illustrates the accompanying drawing of the preferred embodiments of the present invention with exemplary forms, will know above and other purpose of the present invention, feature and advantage from following explanation.

Description of drawings

Fig. 1 is the system diagram of using according to the refrigeration cycle of expansion valve of the present invention.

Fig. 2 is the central longitudinal sectional view according to the structure of first embodiment's expansion valve.

Fig. 3 is the central longitudinal sectional view according to the structure of second embodiment's expansion valve.

Fig. 4 is the central longitudinal sectional view according to the structure of the 3rd embodiment's expansion valve.

Fig. 5 is the central longitudinal sectional view according to the structure of the 4th embodiment's expansion valve.

Fig. 6 is the central longitudinal sectional view according to the structure of the 5th embodiment's expansion valve.

Fig. 7 is the central longitudinal sectional view according to the structure of the 6th embodiment's expansion valve.

Fig. 8 is the central longitudinal sectional view according to the structure of the 7th embodiment's expansion valve.

Embodiment

Hereinafter will be based on being applied to use HFC-134a as refrigeration agent and comprise that the example of the refrigeration cycle of internal exchanger describes embodiments of the invention in detail.

Fig. 1 is that the system diagram according to the refrigeration cycle of expansion valve of the present invention is used in expression.

This refrigeration cycle comprises the condenser 2 of the refrigeration agent that compressor 1, the condensation of compressed refrigerant is compressed, the refrigeration agent throttling that makes cooling and the expansion valve 3 that expands and the vaporizer 4 that makes the refrigeration agent evaporation of expansion.In addition, this refrigeration cycle is included in from condenser 2 and flow to the refrigeration agent of expansion valve 3 and flow to the internal exchanger 5 that carries out heat exchange between the refrigeration agent of compressor 1 from vaporizer 4 via expansion valve 3.

Expansion valve 3 is so-called thermostatic expansion valves, this thermostatic expansion valve has the temperature sensing portion of the temperature and pressure that is used for the refrigeration agent that sensing flows out from vaporizer 4, and is configured for according to the flow velocity of being controlled the refrigeration agent that is delivered to vaporizer 4 by the temperature and pressure of the refrigeration agent of temperature sensing portion sensing.Expansion valve 3 according to the present invention comprises that in inside the high pressure liquid refrigerant that is used to make heat exchanger 5 conveyings internally flow to thebypass channel 3a (being represented by solid arrow) in the downstream side of temperature sensing portion, perhaps is used to make the low-pressure gas-liquid mix refrigerant that is delivered to vaporizer 4 to flow to the bypass channel 3b (being represented by dotted arrow) in the downstream of temperature sensing portion.The details of the structure of expansion valve 3 will be described below.

Fig. 2 is the central longitudinal sectional view according to the structure of first embodiment's expansion valve.

Expansion valve 10 according to first embodiment hasmain body 11, and the side of thismain body 11 is formed with: high-pressure refrigerant inlet 12, high-temperature high-pressure liquid cryogen heat exchanger 5 internally are delivered in this high-pressure refrigerant inlet 12; Lowpressure refrigerant outlet 13 is delivered to vaporizer 4 through the low-temp low-pressure liquid ofexpansion valve 10 throttlings and expansion from this lowpressure refrigerant outlet 13; Coolantchannel inlet 14, thiscoolant channel inlet 14 is used to receive the refrigeration agent through evaporation of from evaporator drier 4; Andcoolant channel outlet 15, the refrigeration agent that thiscoolant channel outlet 15 is used for passing throughexpansion valve 10 is delivered to internal exchanger 5.

Valve seat 16 is integrally formed at high-pressure refrigerant inlet 12 withmain body 11 and exports in the passage that is communicated with between 13 with low pressure refrigerant, and arrangesspherical valve member 17 on the upstream side of valve seat 16.Be provided for the valveelement receiving element 18 and the compressionhelical spring 19 ofreceiving valve element 17 in the space that holdsvalve element 17, this compressionhelical spring 19 promotesvalve element 17 via valveelement receiving element 18 along the direction thatvalve element 17 is placed on the valve seat 16.As shown in Figure 1, the lower end of compressionhelical spring 19 is received by thespring receiving element 20 that is assemblied in the adjustingscrew 21, and adjustingscrew 21 is screwed into the lower end of main body 11.Adjustingscrew 21 has by regulating the amount that itself is screwed in themain body 11 regulates the function of the load of compressionhelical spring 19.

In addition,expansion valve 10 has the temperature sensing portion in the upper end of main body of being arranged on 11.Temperature sensing portion comprisesupper shell 22,lower shell body 23, with barrier film of separately arranging by the mode in the space of described housings close 24 and thedish 25 that is arranged inbarrier film 24 belows.

Indish 25 arranged beneathaxle 26 is arranged, be used for the displacement ofbarrier film 24 is delivered to valve element 17.The top ofaxle 26 is kept byholder 28, andholder 28 is arranged to cross over thecoolant channel 27 that is communicated with betweencoolant channel inlet 14 andcoolant channel outlet 15 and extends.Inholder 28, be furnished with the compressionhelical spring 29 that applies lateral load to the upper end ofaxle 26, thereby the axle that suppresses to be caused by the pressure surge of high-pressure refrigerant 26 vibrates longitudinally along it.

Main body 11 is formed withbypass channel 30, and the high-pressure refrigerant that is delivered in themain body 11 is walked aroundexpansion valve 10 by this bypass channel 30.Bypasschannel 30 is formed between high-pressure refrigerant inlet 12 and thecoolant channel 27, and has the differential pressure control valve in the middle part of inserting it, and wherein high pressure liquid refrigerant is delivered in the high-pressure refrigerant inlet 12.Differential pressure control valve comprises:valve seat 31;Valve element 32, thisvalve element 32 according to the relation relative withvalve seat 31 with can be towards being arranged on the downstream side of thisvalve seat 31 with mode away fromvalve seat 31 motions; Compressionhelical spring 33, this compressionhelical spring 33 promotesvalve element 32 along the valve closing direction; Andspring receiving element 34, thisspring receiving element 34 is force-fitted in thebypass channel 30, is used to receive compression helical spring 33.Rod valve element 32 has a plurality of connectivity slots, and these connectivity slots are formed in the periphery of thisvalve element 32, makes these connectivity slots extend longitudinally, and when differential pressure control valve is opened, the high pressure liquid refrigerant connectivity slot of flowing through.

Expansion valve 10 sensings of Gou Chenging return the pressure and temperature of the refrigeration agent ofcoolant channel inlet 14 from vaporizer 4 as mentioned above.When higher or its pressure is low when the temperature of this refrigeration agent,barrier film 24 is shifted downwards, as shown in Figure 2, and this displacement is passed tovalve element 17 viaaxle 26, thereby makingvalve element 17 open direction along valve moves, and when lower or its pressure is higher, causevalve element 17 to move along the valve closing direction when the temperature of this refrigeration agent, thereby the opening degree ofcontrol expansion valve 10 waits to be delivered to the flow velocity of the refrigeration agent of vaporizer 4 withcontrol.Expansion valve 10 is by the refrigerant temperature in the outlet of sensing vaporizer 4, and control waits to be delivered to the flow velocity of the refrigeration agent of vaporizer 4, thereby control flows into the refrigeration agent ofcoolant channels inlet 14 from vaporizer 4, makes this refrigeration agent have predetermined degree of superheat.

On the other hand, the liquid refrigerant that is delivered to thecoolant channel inlet 14 from vaporizer 4 mixes with the superheated refrigerant of passing throughcoolant channels 27 via bypass channel 30.The bypass amount of coming the controlling liquid refrigeration agent according to the pressure in the high-pressure refrigerant inlet 12 and the pressure reduction between the pressure in the coolant channel 27.When the refrigeration agent load is low, head pressure and the pressure reduction between the suction pressure in the compressor 1 are lower, so pressure and the pressure reduction between the pressure in thecoolant channel 27 that high-pressure refrigerant is gone in 12 are also lower, thereby close the differential pressure control valve that is inserted in the bypass channel 30.In this case, stop liquid refrigerant to flow directly in the downstream side of temperature sensing portion.This is because when the refrigeration agent load is low, be not very high by the temperature of compressor 1 refrigerant compressed.

When refrigeration agent is loaded when higher, head pressure in the compressor 1 and the pressure reduction between the suction pressure increase, and pressure in the high-pressure refrigerant inlet 12 and the pressure reduction between the pressure in thecoolant channel 27 also increase, thereby the pressure reduction at the differential pressure control valve two ends becomes when being equal to or higher than predetermined value (for example 1.3MPa), the Driving force of differential pressure control valve opposing compressionhelical spring 33 and opening is so that liquid refrigerant flows into the downstream side of temperature sensing portion and mixes with liquid refrigerant under the superheat state.Thereby this temperature that has reduced the refrigeration agent under the superheat state makes mixture become wet refrigeration agent.Internal exchanger 5 makes this refrigeration agent and the refrigeration agent heat exchange that reduces from the temperature of condenser 2, thereby this refrigeration agent is evaporated and overheated, and makes overheated refrigeration agent be inhaled into compressor 1.Therefore, prevented that the temperature that sucks the refrigeration agent of compressor 1 from becoming too high, this has prevented to be become too high by the temperature of compressor 1 refrigerant compressed.This prevented in the compressor 1 with the thermal metamorphism of refrigeration agent through the lubricant oil of refrigeration cycle circulation.

Fig. 3 is the central longitudinal sectional view according to the structure of second embodiment's expansion valve.In Fig. 3, the composed component identical with composed component shown in Figure 2 represented by identical reference character, and omitted detailed description.

With different is according to first embodiment's expansion valve 10 (wherein inserting differential pressure control valve in bypass channel 30), be characterised in that according to second embodiment's expansion valve 40bypass channel 30 is provided with and opens wide the verylittle hole 35 of degree.According to the expansion valve 40 that constitutes as mentioned above, the liquidrefrigerant bypass channel 30 of always flowing through.Therefore, may be too low though when the refrigeration agent load is low, be delivered to the temperature of the refrigeration agent of internal exchanger 5, compare withexpansion valve 10 according to first embodiment, can reduce cost.

Fig. 4 is the central longitudinal sectional view according to the structure of the 3rd embodiment's expansion valve.In Fig. 4, the composed component identical with composed component shown in Figure 2 represented by identical reference character, and omitted detailed description.

With different is according to first embodiment's expansion valve 10 (whereinbypass channel 30 is formed between high-pressure refrigerant inlet 12 and the coolant channel 27),expansion valve 50 according to the 3rd embodiment is characterised in thatbypass channel 30 passesmain body 11 and is formed between lowpressure refrigerant outlet 13 and thecoolant channel 27.

Inexpansion valve 50, though differential pressure control valve is inserted in thebypass channel 30, the spring-load of compressionhelical spring 33 is arranged so that when the pressure reduction of differential pressure control valve at its two ends is not less than the predetermined value of 0.03MPa for example and opens.By this structure, when the refrigeration agent load is low, the flow velocity of refrigeration agent of vaporizer 4 of flowing through is lower, therefore pressure and the pressure reduction between the pressure in its outlet in the inlet of vaporizer 4 is also lower, and this pressure reduction is approximately equal to the pressure reduction at the differential pressure control valve two ends in insertingbypass channel 30, thereby differential pressure control valve is closed.As a result, when high pressure liquid refrigerant is flowed through gap betweenvalve element 17 and thevalve seat 16, export all gas-liquid mixed refrigerants that expand at 13 places at low pressure refrigerant and all be transported to vaporizer 4, and be prevented from flowing directly in the downstream side of temperature sensing portion.

Load when higher when refrigeration agent, the flow velocity of the refrigeration agent of the vaporizer 4 of flowing through is higher, so the pressure reduction between the pressure in the pressure in the inlet of vaporizer 4 and its outlet becomes higher, that is, the pressure reduction at the differential pressure control valve two ends increases.When this pressure reduction becomes when being equal to or higher than predetermined value, the Driving force of differential pressure control valve opposing compressionhelical spring 33 and opening so that liquid refrigerant flow into temperature sensing portion the downstream side and with superheat state under refrigerant mixed.Therefore, prevent that the temperature that sucks the refrigeration agent in the compressor 1 from becoming too high, this has also prevented to be become too high by the temperature of compressor 1 refrigerant compressed.This has also prevented the thermal metamorphism of the lubricant oil in the compressor 1.

Fig. 5 is the central longitudinal sectional view according to the structure of the 4th embodiment's expansion valve.In Fig. 5, the composed component identical with composed component shown in Figure 3 represented by identical reference character, and omitted detailed description.

Similar with expansion valve 40 according to second embodiment, inbypass channel 30, formporose 35 according to the 4th embodiment's expansion valve 60.According to theexpansion valve 60 of structure as mentioned above, the gas-liquid mixedrefrigerant bypass channel 30 of always can flowing through.As mentioned above, the refrigerant mixed of the gas-liquid mixed refrigerant and the coolant channel of flowing through, thus reduction is delivered to the temperature of the refrigeration agent of internal exchanger 5, and this has prevented to be become too high by the temperature of compressor 1 refrigerant compressed.

Fig. 6 is the central longitudinal sectional view according to the structure of the 5th embodiment's expansion valve.In Fig. 6, the composed component identical with composed component shown in Figure 2 represented by identical reference character, and omitted detailed description.

In theexpansion valve 70 according to the 5th embodiment,bypass channel 30 forms by passing the through hole thatmain body 11 forms, and makesaxle 26 insertions that are arranged between temperature sensing portion and thevalve element 17 pass this throughhole.In bypass channel 30, thevalve element 32 of differential pressure control valve can be arranged to be used for the guide ofaxle 26 with axial motion, and compressionhelical spring 33 is arranged betweenvalve element 32 and theholder 28, and the direction on thevalve seat 31 that is used for forming along the stepped part thatvalve element 32 is placed in bybypass channel 30 promotesvalve element 32.

When comparing according to theexpansion valve 50 of Fig. 4 of the 3rd embodiment, the difference ofexpansion valve 70 andexpansion valve 50 only is the position ofbypass channel 30, and thisexpansion valve 70 has the differential pressure control valve that is arranged in thebypass channel 30, and the pressure reduction of this differential pressure control valve at its two ends becomes when being equal to or higher than predetermined value to be opened.Therefore,expansion valve 70 is operated in identical mode.

In addition, though the position arrange openings relative with temperature sensing portion atcoolant channel 27, refrigeration agent is supplied tocoolant channel 27 by this opening frombypass channel 30, but passing the low temperature gas-liquid mixed refrigerant that differential pressure control valve is supplied tocoolant channel 27 frombypass channel 30 is come the refrigeration agent of from evaporator drier 4 to transport towardscoolant channel outlet 15 immediately, thereby gas-liquid mixed refrigerant is mixed in the downstream side of temperature sensing portion with the refrigeration agent that returns from vaporizer 4, and its temperature is not sensed by temperature sensing portion.

Fig. 7 is the central longitudinal sectional view according to the structure of the 6th embodiment's expansion valve.In Fig. 7, the composed component identical with composed component shown in Figure 3 represented by identical reference character, and omitted detailed description.

In theexpansion valve 80 according to the 6th embodiment,bypass channel 30 forms by passing the through hole thatmain body 11 forms, and makes that being arranged inaxle 26 between temperature sensing portion and thevalve element 17 inserts and pass this through hole, andformation porose 35 in its intermediateportion.Expansion valve 80 is in the configuration aspects that wet refrigeration agent is always mixed with the superheated refrigerant of carrying from vaporizer 4 and basic identical according to theexpansion valve 60 of Fig. 5 of the 4th embodiment, soexpansion valve 80 is operated in the mode identical withexpansion valve 60.

Fig. 8 is the central longitudinal sectional view according to the structure of the 7th embodiment's expansion valve.In Fig. 8, the composed component identical with composed component shown in Figure 4 represented by identical reference character, and omitted detailed description.

Expansion valve 90 according to the 7th embodiment is applied to a refrigeration cycle, and this refrigeration cycle adoptsbimetallic tube 36 conducts at the pipe on the side of compressor 1 and condenser 2.Bimetallic tube 36 forms by arrangingouter tube 36a andinterior pipe 36b coaxially, and because the refrigeration agent of the refrigeration agent of theouter tube 36a that flows through and theinterior pipe 36b that flows through is separated byinterior pipe 36b, sobimetallic tube 36 has the function of internal exchanger 5.

Expansion valve 90 has the high-pressure refrigerant inlet 12 that is arranged on the side thatvalve element 17 opens wide, and being arranged in compressionhelical spring 19 andspring receiving element 20 on the downstream side of valve element 7, the high-temperature high-pressure liquid cryogen is delivered to high-pressure refrigerant inlet 12 from condenser 2.Bypasschannel 30 is formed between the low-temp low-pressure chamber andcoolant channel 27 of arrangement ofvalves element 17, and the refrigeration agent that returns from vaporizer 4 passes through coolant channel 27.The open end of leading tocoolant channel 27 atbypass channel 30 is furnished withvalve element 32, andvalve element 32 is remaining on along the mode that the direction that opens and closesbypass channel 30 is moved on the axle 26.Valveelement 32 is compressedhelical spring 33 and promotes along the direction thatvalve element 32 is placed on thevalve seat 31, thereby forms differential pressure control valve.

From theouter tube 36a ofbimetallic tube 36 be delivered to high-temperature high-pressure liquid cryogen the high-pressure refrigerant inlet 12 through the gap betweenvalve element 17 and thevalve seat 16 time by throttling and expand into low-temperature low-pressure refrigerant, and export 13 from low pressure refrigerant and be delivered to vaporizer 4.The refrigeration agent that returns from vaporizer 4 is received bycoolant channel inlet 14, and is delivered to theinterior pipe 36b ofbimetallic tube 36 fromcoolant channel outlet 15 through coolant channel 27.At this moment, temperature sensing portion sensing is through the temperature and pressure of the refrigeration agent ofcoolant channel 27, thereby control waits to be delivered to the flow velocity of the refrigeration agent of vaporizer 4.

In addition, pressure reduction between the pressure that is arranged in the refrigeration agent in the differential pressure control valve sensing lowpressure refrigerant outlet 13 in thebypass channel 30 and the pressure of the refrigeration agent in thecoolant channel 27, thus controlexports 13 flow velocitys that flow to the refrigeration agent ofcoolant channel 27 from low pressure refrigerant.Though the position relative with temperature sensing portion atcoolant channel 27 forms opening, refrigeration agent is supplied tocoolant channel 27 by this opening frombypass channel 30, but the low temperature gas-liquid mixed refrigerant that is supplied tocoolant channel 27 through differential pressure control valves frombypass channel 30 is transported towardscoolant channel outlet 15 by the refrigeration agent of vaporizer 4 evaporations, thereby the temperature of gas-liquid mixed refrigerant is not by temperature sensing portion sensing.

Though in the above-described embodiments, described being applied to have internal exchanger and using the example of HFC-134a, but the present invention also can be applicable to use the refrigeration cycle of less and other refrigeration agent that physical property is similar of global warming coefficient as the refrigeration cycle of refrigeration agent.

Expansion valve according to the present invention is constructed such that wet refrigeration agent flows to the downstream side of temperature sensing portion through bypass channel.Therefore, when the present invention is applied to adopt the refrigeration cycle of internal exchanger, can reduce the temperature for the treatment of to be delivered to the refrigeration agent of compressor via heat exchanger.This makes and can prevent to be become too high by the temperature of compressor refrigerant compressed under high cooling load situation, thereby prevents the thermal metamorphism of the lubricant oil in the compressor.

Below only as explanation of the principles of the present invention.In addition, because those skilled in the art carry out many modifications and changes easily, so shown in not wishing the present invention is defined in and described precise structure and application, so all suitable modifications and equivalent can be thought to drop in the scope of the present invention in claims and the equivalent thereof.

Claims (8)

1. thermostatic expansion valve, this thermostatic expansion valve are configured to control by the temperature and pressure that makes the refrigeration agent that temperature sensing portion sensing flows out from vaporizer the flow velocity of the refrigeration agent of waiting to be delivered to vaporizer, and this thermostatic expansion valve comprises:

Bypass channel, this bypass channel is formed between high-pressure refrigerant inlet or low pressure refrigerant outlet and the coolant channel, be used to make high pressure liquid refrigerant or low-pressure gas-liquid mix refrigerant to flow to the downstream side of described temperature sensing portion, wherein high-pressure refrigerant is supplied to described high-pressure refrigerant inlet, low pressure refrigerant is delivered to described vaporizer from described low pressure refrigerant outlet, and described coolant channel passes through the described refrigeration agent that flows out from described vaporizer.

2. expansion valve according to claim 1 is characterized in that, described bypass channel is to pass main body to be formed on hole between described high-pressure refrigerant inlet and the described coolant channel.

3. expansion valve according to claim 1, it is characterized in that, described bypass channel is formed in the passage between described high-pressure refrigerant inlet and the described coolant channel and has differential pressure control valve passing main body, and the pressure reduction of this differential pressure control valve at its two ends becomes and opens when being not less than predetermined value.

4. expansion valve according to claim 1 is characterized in that, described bypass channel is to pass main body to be formed on hole between outlet of described low pressure refrigerant and the described coolant channel.

5. expansion valve according to claim 1, it is characterized in that, described bypass channel is formed in the passage between outlet of described low pressure refrigerant and the described coolant channel and has differential pressure control valve passing main body, and the pressure reduction of this differential pressure control valve at its two ends becomes and opens when being not less than predetermined value.

6. expansion valve according to claim 1, it is characterized in that described bypass channel is to pass the through hole that main body forms, and makes an insertion pass this through hole, described axle is arranged between described temperature sensing portion and the valve element, and this valve element control is delivered to the flow velocity of the refrigeration agent of described vaporizer.

7. expansion valve according to claim 1, it is characterized in that, described bypass channel has differential pressure control valve in through hole, the pressure reduction of this differential pressure control valve at its two ends becomes and opens when being not less than predetermined value, described through hole passes main body and forms, make an insertion pass this through hole, described axle is arranged between described temperature sensing portion and the valve element, and this valve element control is delivered to the flow velocity of the refrigeration agent of described vaporizer.

8. expansion valve according to claim 1 is characterized in that this expansion valve is applied to be provided with the refrigeration cycle of internal exchanger, and described heat exchanger carries out heat exchange between the refrigeration agent of refrigeration agent that flows out from condenser and suction compressor.

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