JP2002162133A - Freezing cycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezing cycle which need not be provided with a relief valve independently, in a freezing cycle which may get in the condition where the pressure of a high pressure line is over the critical pressure of a refrigerant. SOLUTION: A pressure controller, which depressurizes and expands a refrigerant cooled with a radiator has a housing which has a refrigerant flow inlet leading to the side of the radiator and a refrigerant flow outlet leading to the side of the radiator, a valve element 24 which changes the connection state between the inlet side of the refrigerant flow and the outlet side of the refrigerant flow, a first reply member 25 which couples with the valve element 24 within the housing and controls the quantity of lifting of the valve element 24 by sensing the refrigerant state on the side of the radiator an operating, a second reply means 26 which is provided with its operational direction in accord with the first reply member 25 and senses the refrigerant pressure on radiator side and operates and lifts the valve element compulsively in case that the pressure on the radiator side comes to specified pressure or over.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

THE INVENTION Field of the Invention The present invention, carbon dioxide (CO ₂₎ or the like is used as the refrigerant, relates to a refrigeration cycle which can be a state in which the pressure of the high pressure line exceeds a critical pressure of the refrigerant.

[0002]

2. Description of the Related Art In a refrigeration cycle using carbon dioxide as a refrigerant, when the cycle is stopped, the pressure in a high pressure line and the pressure in a low pressure line gradually approach each other, and an equilibrium pressure of 8 to 10 is reached.
When the cycle is started from this state, the pressure in the high pressure line suddenly rises abnormally due to a time lag between the discharge start timing of the compressor and the operation timing of the expansion device, and the inconvenience reaches 15 MPa or more. There is. Therefore, in order to cope with such an abnormal rise in the pressure, it has been considered to provide a relief valve as disclosed in Japanese Patent Application Laid-Open No. H11-248272. In a refrigeration cycle having a compressor, a radiator, a pressure control valve, and an evaporator, this is a bypass passage that bypasses the pressure control valve and guides the refrigerant at the radiator outlet side (high pressure line) to the evaporator side (low pressure line). And a relief valve that opens when the refrigerant pressure in the high pressure line becomes equal to or higher than a predetermined pressure is provided in the bypass passage.

[0003]

However, in the above-mentioned structure, since the relief valve must be provided in parallel with the pressure control valve, a valve element having each function and a response control for controlling the movement of the valve element are required. It is necessary to provide members separately, and it is necessary to separately provide a path in which each valve element is disposed (secure a bypass path in which a relief valve is disposed in addition to a main path in which a pressure control valve is disposed). Need to provide a relief valve separately from the pressure control valve.
In other words, there is a concern that the number of parts may be increased and the external dimensions may be increased.

[0004] Therefore, in the present invention, in a refrigeration cycle using carbon dioxide (CO ₂ ) or the like as a refrigerant, the pressure of a high-pressure line may exceed the critical pressure of the refrigerant.
An object of the present invention is to provide a refrigeration cycle that does not require a separate relief valve.

[0005]

In order to achieve the above object, a refrigeration cycle according to the present invention comprises: a compressor for compressing a refrigerant to make the pressure of the compressed refrigerant higher than a critical pressure according to operating conditions; A radiator that cools the refrigerant compressed by the compressor, a pressure control device that decompresses and expands the refrigerant cooled by the radiator, and an evaporator that evaporates the refrigerant flowing out of the pressure control device. A housing having a refrigerant inlet communicating with the radiator side and a refrigerant outlet communicating with the evaporator side, and changing a communication state between the refrigerant inlet side and the refrigerant outlet side with the pressure control device. A first responsive member connected to the valve body in the housing and sensing and operating a refrigerant state on the radiator side to control a lift amount of the valve body; Response A material that is provided in the same operating direction as the material, operates by sensing the refrigerant pressure on the radiator side, and forcibly lifts the valve body when the pressure on the radiator side is equal to or higher than a predetermined pressure. And two response members (claim 1).

Therefore, separately from the first responding member for controlling the movement of the valve body by the pressure control device, the second forcibly lifting the valve body when the pressure on the radiator side becomes a predetermined pressure or more. When the refrigerant pressure is lower than a predetermined pressure, the second response member does not operate, and only the first response member operates according to the state of the refrigerant on the radiator side. As a result, the lift amount of the valve body is controlled, and the refrigerant in the high-pressure line is decompressed and expanded. On the other hand, when the pressure reaches or exceeds the predetermined pressure, the second responsive member is operated to forcibly open the valve body, thereby relieving the refrigerant in the high pressure line to the evaporator side. You can do it. For this reason, the pressure control device can have both the function of decompressing and expanding the refrigerant and the function of relieving the high-pressure refrigerant, so that an abnormal increase in pressure at the time of starting the cycle can be performed without providing a relief valve individually. Can be avoided.

Here, as the second responsive member, a bellows filled with a working medium having a characteristic that the operating pressure becomes substantially constant with respect to the change of the refrigerant temperature is connected in series to the first responsive member. Even if it is constituted (claim 2), the housing is provided with a mechanism for expanding when the refrigerant temperature that changes in conjunction with the refrigerant pressure on the radiator side becomes equal to or higher than the temperature corresponding to the predetermined pressure. Even when the first responsive member is displaced in accordance with the expansion and contraction of the housing (claim 3), a movable member displaced together with the first responsive member in the movable direction of the valve body is provided, and the movable member is provided. The refrigerant pressure on the radiator side acts on the valve in the valve opening direction, and the movable body is displaced in the valve opening direction when the pressure on the radiator side becomes equal to or higher than a predetermined pressure. Item 4). Further, the first response member may be constituted by a pressure-sensitive element such as a bellows or a diaphragm in which a refrigerant or a working medium having the same characteristics as the refrigerant is sealed (claim 7).

[0008] Further, a compressor for compressing the refrigerant to make the pressure of the compressed refrigerant higher than a critical pressure according to operating conditions, a radiator for cooling the refrigerant compressed by the compressor, and cooling by the radiator In a refrigeration cycle configured to include at least a pressure control device that decompresses and expands the compressed refrigerant and an evaporator that evaporates the refrigerant flowing out of the pressure control device, the pressure control device is connected to a radiator side. A housing having a refrigerant outlet communicating with the refrigerant inlet and the evaporator side, a valve body that changes a communication state between the refrigerant inlet side and the refrigerant outlet side, and the valve body in the housing. A first sealed space in which the first working medium is sealed, and a volume of the first sealed space is changed according to a state of the refrigerant on the radiator side, so that the valve body is refilled. A first responsive member for controlling the amount of gas, and a second closed space disposed in the first closed space and enclosing a second working medium, and having a capacity of the second closed space. A second responsive member configured to reduce the pressure when the pressure in the first closed space becomes equal to or higher than a predetermined pressure, wherein the density of the second working medium is higher than the density of the first working medium. You may make it small (claim 5).

According to this structure, the second responsive member that contracts when the pressure in the closed space becomes equal to or higher than the predetermined pressure is disposed in the closed space of the first responsive member. The density of the second working medium enclosed in the enclosed space of the first
When the refrigerant pressure is lower than a predetermined pressure, the first working medium sealed in the first closed space is set to be smaller than the density of the first working medium sealed in the closed space. Since the pressure transmitted through the second responsive member is also smaller than the predetermined pressure, there is no change in the volume of the second responsive member, and only the first responsive member operates according to the state of the refrigerant on the radiator side, and the lift amount of the valve body is reduced. Under the control, the refrigerant in the high pressure line is decompressed and expanded. On the other hand, when the refrigerant pressure has reached the predetermined pressure or higher, the pressure transmitted via the first working medium also has the predetermined pressure or higher, so that the second responsive member contracts,
Moreover, since the density of the second working medium is set to be smaller than the density of the first working medium, the contracted volume of the second responsive member is larger than the contracted volume of the first responsive member. And the first responsive member is further contracted by the contracted volume difference to forcibly lift the valve body,
Thereby, the refrigerant in the high pressure line can be relieved to the evaporator side. For this reason, the pressure control device can have both the function of decompressing and expanding the refrigerant and the function of relieving the high-pressure refrigerant, so that an abnormal increase in pressure at the time of starting the cycle can be performed without providing a relief valve individually. Can be avoided.

Here, the second responsive member is provided with a second characteristic having a characteristic that the operating pressure is substantially constant with respect to a change in the refrigerant temperature.
(Claim 6), and the first responsive member is constituted by a bellows or a diaphragm enclosing a refrigerant or a working medium having the same characteristics as the refrigerant. (Claim 7).

The above-described pressure control device is suitable for a vapor compression refrigeration cycle in which the pressure in the high pressure line can exceed the critical pressure of the refrigerant, for example, a refrigeration cycle using carbon dioxide as the refrigerant ( Claim 8).

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a refrigeration cycle 1
Is a refrigerant having a low critical point, for example, carbon dioxide (CO ₂ )
, A compressor 2 for compressing the refrigerant, a radiator 3 for cooling the refrigerant, an internal heat exchanger 4 for exchanging heat between the high-pressure line and the low-pressure line, and a pressure control device 5 for decompressing and expanding the refrigerant. , Evaporator 6 for evaporating and evaporating the refrigerant, evaporator 6
It has an accumulator 7 that separates the refrigerant flowing out of the tank into gas and liquid. In this refrigeration cycle,
The discharge side (D) of the compressor 2 is connected to the high-pressure passage 4 a of the internal heat exchanger 4 via the radiator 3, and the discharge side of the high-pressure passage 4 a is connected to the pressure control device 5. High-pressure line 8 by the path from the side to expansion device 5
Are formed. The outlet side of the pressure control device 5 is connected to the low-pressure passage 4b of the internal heat exchanger 4 via the evaporator 6 and the accumulator 7, and the outlet side of the low-pressure passage 4b is connected to the suction side (S) of the compressor 2. A low-pressure line 9 is formed by a path from the outflow side of the expansion device 5 to the compressor 2.

FIGS. 2 and 3 show a first configuration example of the pressure control device 5. The pressure control device 5 includes a first and a second pressure control device 5 in a housing 10 which is constructed by assembling housing members 10a and 10b. It has two high-pressure spaces 11 and 12 and a low-pressure space 13. In this example, the first and second high-pressure spaces 11 and 12 are configured by partitioning a space surrounded by one housing member 10a and the other housing member 10b by a partition wall 14, and a first high-pressure space. The 11 and the second high-pressure space 12 communicate with each other via a communication hole 15 formed in the partition wall 14. Further, the low-pressure space 13 is connected to one of the housing members 10.
b, and communicates with the first high-pressure space 11 through a communication hole 17 of a partition 16 provided in the housing member 10b.

A refrigerant inlet 19 connected to a pipe 18 communicating with the high-pressure passage 4a of the internal heat exchanger 4 (communicating with the radiator) is provided at a portion of the housing member 10a facing the first high-pressure space 11. Formed and housing member 1
A refrigerant outlet 21 to which a pipe 20 communicating with the evaporator 6 is connected is formed in a portion facing the low-pressure space 13 of Ob.

The first high-pressure space 11 accommodates a pressure-reducing control valve 22. The pressure-reducing control valve 22 is seated on a valve seat 23 formed on a valve seat 23 formed on the periphery of the opening facing the high-pressure space 11 of the communication hole 17. And a first bellows 25 joined to the valve element 24. This first bellows 2
Numeral 5 is provided to be extendable and contractible in the movable direction of the valve body 24 while being held by a connecting member 30 described below.
FIG. 4A shows a working medium having a relationship between temperature and pressure, that is, a refrigerant gas having a property in which the pressure of the working medium increases with an increase in temperature, that is, a carbon dioxide gas (CO ₂ ). Are sealed at a predetermined density.

Therefore, the first bellows 25 is
, The refrigerant state (refrigerant pressure, refrigerant temperature) on the radiator 3 side is detected and expanded and contracted to control the lift amount of the valve body 24. The refrigerant discharged from the radiator 3 can be guided to the evaporator after being decompressed and expanded. That is,
The first bellows 25 allows the pressure control device 5 to function as an expansion valve.

The second high-pressure space 12 accommodates a second bellows 26 provided in such a manner that the operation direction (expansion / contraction direction) of the first bellows 25 is the same as that of the first bellows 25. In the second bellows 26, there is a working medium having a relationship between temperature and pressure shown in FIG. 4B, that is, a property that the pressure of the working medium is substantially constant regardless of a change in temperature. For example, an inert gas (such as nitrogen) is sealed at a predetermined density.

Therefore, the second bellows 26 is
Has the function of detecting the pressure of the high-pressure space 12, that is, the pressure on the radiator 3 side, and contracting when the pressure on the radiator side becomes a predetermined pressure (Pr) or more (for example, 15 MPa or more). are doing. The second bellows 26 has one end fixed to the top of the housing member 10 a and the other end connected to the connecting member 30.

The connecting member 30 includes a connecting rod 30a inserted through the partition wall 14, a first stopper portion 30b formed at one end of the connecting rod 30a and connected to the other end of the second bellows 26, A second stopper portion 30 formed at the other end of the connecting rod 30a and having an end opposite to the side on which the valve element 24 of the first bellows 25 is provided fixed.
c and a second stopper portion 30 c extending from the second stopper portion 30 c so as to cover the bellows 25.
Stopper portion 30d provided to be lockable from the side of
And is configured.

The connecting rod 30a is formed to be longer than the thickness of the partition wall 14, and the connecting member 30 is moved from the state where the first stopper portion 30b is in contact with the partition wall 14 to the second stopper portion 30c which is connected to the partition wall 14. The valve body 24 can be displaced in the same direction as the operation direction until the contact state is reached. In other words, the operation of the first bellows 25 and the second bellows 26 in the expanding direction is restricted by the connecting member 30 so that the function of each bellows is not obstructed by the other bellows, and , First
The bellows 25 and the valve body 24 can be displaced together with the connecting member 30.

The length of the connecting rod 30a is set so that the valve body 24 can be seated on the valve seat 23 without being hindered by the third stopper portion 30d when the first stopper portion 30b is in contact with the partition wall 14. At the same time, when the second stopper portion 30c is in contact with the partition wall 14, the valve body 24 is formed to have a length capable of completely opening the communication hole 17, and the connecting member 30 is provided on the radiator side. Until the pressure becomes equal to or higher than the predetermined pressure (Pr), the first stopper portion 30b is in contact with the partition wall 14 by the urging force from the second bellows 26.

In the above-described structure, the refrigerant (CO ₂ ) compressed by the compressor 2 enters the radiator 3 as a high-temperature and high-pressure refrigerant, radiates and cools the refrigerant, and further cools the internal heat exchanger 4.
Is cooled by heat exchange with the low-temperature refrigerant flowing out of the evaporator 6, and sent to the pressure control device 5 without being liquefied. At this time, if the pressure of the refrigerant reaching the pressure control device 5 is lower than a predetermined pressure (Pr), the contact state between the first stopper portion 30b and the partition wall 14 shown in FIG. Therefore, the lift amount of the valve body 24 is adjusted by the first bellows 25 according to the refrigerant state (refrigerant pressure, refrigerant temperature) on the radiator side.
Is expanded under reduced pressure and supplied to the evaporator 6. And the refrigerant supplied to the evaporator 6 is:
The evaporator 6 exchanges heat with air passing through the evaporator 6 to become gaseous, and then returns to the compressor 2 after exchanging heat with the high-temperature refrigerant in the high-pressure line 8 in the internal heat exchanger 4.

On the other hand, if the refrigerant pressure reaching the pressure control device 5 is equal to or higher than a predetermined pressure (Pr), the second bellows 26 contracts as shown in FIG. Is lifted, whereby the valve body 24 is forcibly lifted by the third stopper portion 30c, and the valve body 2 is lifted.
A gap is formed between 4 and communication hole 17. For this reason,
The refrigerant flowing out of the radiator 3 is relieved from the first high-pressure space 11 to the low-pressure space 13 through the communication hole 17 and can be guided to the evaporator 6 side. That is, when the pressure of the high-pressure line 8 is going to rise abnormally at the start of a cycle or the like, the high-pressure refrigerant can be relieved to the low-pressure line 9 at the initial stage. Will be able to

Therefore, according to the pressure control device 5 described above, when the refrigerant pressure in the high-pressure line 8 is lower than the predetermined value (Pr), the operation of the first bellows 25 causes the pressure reducing control valve 22 to function as an expansion valve. When the refrigerant pressure in the high-pressure line 8 reaches a predetermined pressure (Pr) or more, the operation of the second bellows 26 causes the pressure-reducing control valve 22 to function as a relief valve, so that the characteristics shown in FIG. It is possible to provide the characteristic shown by the solid line in FIG. 4C, which is a combination of the characteristic shown in FIG. 4B. Therefore, it is necessary to separately provide a relief valve which was conventionally required as a separate member. Disappears.

According to the above configuration, the high-pressure line 8
Is low, the extension of the second bellows 26 is limited by bringing the first stopper portion 30b into contact with the partition wall 14, so that the pressure on the radiator side is reduced and the second bellows 26 functions as an expansion valve. In this case, the first bellows 25 is no longer biased more than necessary in the valve closing direction, and the operation of the first bellows 25 is prevented from being disturbed by the excessive expansion of the second bellows 26. become able to.

FIG. 5 shows a second configuration example of the pressure control device 5. In this configuration, the pressure control device 5 includes a high-pressure space 32 and a low-pressure space in a housing 31 configured by assembling housing members 31a and 31b. 33. In this example, the high-pressure space 32 is constituted by a space surrounded by one housing member 31a and the other housing member 31b, and the low-pressure space 33 is formed in one housing member 31b.
The low pressure space 33 is communicated with the low pressure space 33 through a communication hole 35 of a partition wall 34 provided in the housing member 31b.

A refrigerant inlet 37 is formed in a portion of the housing member 31a facing the high-pressure space 32. The refrigerant inlet 37 is connected to a pipe 36 communicating with the high-pressure passage 4a of the internal heat exchanger 4 (communicating with the radiator). A pipe 3 leading to the evaporator 6 is provided at a portion of the housing member 31b facing the low-pressure space 33.
A refrigerant outlet 39 to which the refrigerant 8 is connected is formed.

The high-pressure space 32 houses a pressure-reducing control valve 40. The pressure-reducing control valve 40 is connected to the high-pressure space 32 of the communication hole 35.
4 seated on valve seat 41 formed on the periphery of the opening facing
2 and a bellows 43 joined to the valve element 42. The bellows 43 is fixed to the top of the housing member 31a, and has a working medium having a characteristic of a relationship between temperature and pressure shown in FIG. For example, a refrigerant gas having a characteristic that increases as the pressure rises, that is, carbon dioxide (CO ₂ ) is sealed at a predetermined density.

Therefore, the bellows 43 is
The lift amount of the valve body 42 is controlled by sensing and expanding and contracting the refrigerant state in the radiator 3, that is, the refrigerant state (refrigerant pressure, refrigerant temperature) on the radiator 3 side.
Thereby, the pressure reduction control valve 40 can be made to function as an expansion valve.

The housing member 31a is provided with an expansion / contraction mechanism 44 that expands when the refrigerant temperature that changes in conjunction with the refrigerant pressure on the radiator side reaches a predetermined temperature or higher. The expansion / contraction mechanism 44 forms a part of the side wall of the housing member 31a in a bellows shape that can expand and contract in the movable direction of the valve body 42, and the part formed in the bellows shape becomes, for example, when a predetermined temperature or higher is reached. The bellows 43 can be displaced in the movable direction of the valve body 42 with the expansion and contraction of the housing member 31a. Here, the temperature at which the expansion and contraction mechanism 44 is expanded is determined by the pressure at which relief is required in the characteristic line of FIG. 4A showing the relationship between the refrigerant pressure on the radiator side and the refrigerant temperature that changes in conjunction with this. Temperature T corresponding to Pr
r.

Therefore, according to such a configuration, the refrigerant pressure reaching the pressure control device 5 becomes the pressure P at which the relief is requested.
If the pressure is lower than r, as shown in FIG. 5A, the expansion and contraction mechanism 44 provided on the housing 31 maintains the contracted state, and the bellows 43 causes the refrigerant on the radiator 3 side to move. The lift amount of the valve body 42 is adjusted according to the state (refrigerant pressure, refrigerant temperature), whereby the refrigerant flowing out of the radiator 3 is decompressed and expanded and supplied to the evaporator 6.

On the other hand, when the pressure of the refrigerant reaching the pressure control device 5 becomes equal to or higher than the pressure Pr for requesting the relief, as shown in FIG. The mechanism 44 expands and the bellows 43 is lifted together with the valve body 42, and the valve body 42 is forcibly separated from the communication hole 35, so that a gap is formed between the valve body 42 and the communication hole 35. Therefore, the high-pressure refrigerant flowing out of the radiator 3 can be relieved from the high-pressure space 32 to the low-pressure space 33 through the communication hole 35 and guided to the evaporator 6 side.
That is, when the pressure of the high-pressure line 8 is going to rise abnormally at the start of a cycle or the like, the high-pressure refrigerant can be relieved to the low-pressure line 9 at the initial stage. Will be able to

Therefore, according to the pressure control device 5 described above, if the pressure in the high pressure line 8 is lower than the predetermined value Pr, the pressure reducing valve 40 is operated by the normal operation of the bellows 43.
Can function as an expansion valve, and when the pressure of the high-pressure line 8 is equal to or higher than a predetermined pressure Pr, the pressure reducing control valve 40 can function as a relief valve by the action of the expansion and contraction mechanism 44 provided in the housing 31. As in the above configuration example, the characteristic shown in FIG. 4C can be provided, so that there is no need to separately provide a relief valve which was conventionally required as a separate member.

In FIG. 5, the operating width (expandable width) of the expandable mechanism 44 provided in the housing 31 is exaggerated, but in practice, the valve body 42 is forcibly moved by several millimeters. And the operation of the telescopic mechanism 44 may be instantaneous. Further, the extension mechanism 44
May be operated from a pressure slightly lower than the pressure Pr for requesting the relief of the high-pressure refrigerant.

FIG. 6 shows a third configuration example of the pressure control device 5. In this configuration, the pressure control device 5 includes a high-pressure space 46 in a housing 45 formed by assembling housing members 45a and 45b. It has a sealed space 47 separated from the high-pressure space 46 and a low-pressure space 48. The high-pressure space 46 and the enclosed space 47 are configured by partitioning a space surrounded by one housing member 45a and the other housing member 45b by a movable body 50, and the low-pressure space 48 is formed by one housing member. 45b, the high-pressure space 46 and the low-pressure space 4
8 is communicated through a communication hole 52 of a partition wall 51 provided in the housing member 45b.

A refrigerant inlet 54 is formed in a portion of the housing member 45a facing the high-pressure space 46. The refrigerant inlet 54 is connected to a pipe 53 communicating with the high-pressure passage 4a of the internal heat exchanger 4 (communicating with the radiator). A pipe 5 communicating with the evaporator 6 is provided at a portion of the housing member 45b facing the low-pressure space 48.
The refrigerant outlet 56 to which the cooling medium 5 is connected is formed.

The movable body 50 includes a housing member 45a.
The inner peripheral surface of the housing member 4 can be displaced in the movable direction of the valve body 57 described below while slidingly contacting the inner peripheral surface of the housing member 4.
The displacement of the high-pressure space 46 in the direction of reducing the size thereof is limited by the stopper 58 formed in 5a.

The high-pressure space 46 accommodates a pressure-reducing control valve 60.
5 seated on a valve seat 61 formed on the periphery of the opening facing the
7 and a bellows 63 joined to the valve body 57. The bellows 63 is fixed to the movable body 50 so as to be displaced together with the movable body 50, and has a working medium in which the relationship between temperature and pressure has a characteristic shown in FIG. For example, refrigerant gas having a characteristic that the pressure of the working medium increases with an increase in temperature,
That is, carbon dioxide (CO ₂ ) is sealed at a predetermined density. Also, the enclosing space 47 has a working medium having a relationship between temperature and pressure having the characteristics shown in FIG. 4B, that is, a working medium having a characteristic in which the pressure of the working medium is substantially constant regardless of a change in temperature. An inert gas (such as nitrogen) is sealed at a predetermined density.

Therefore, the bellows 63 is
6, the lift amount of the valve body 57 is controlled by detecting and expanding and contracting the refrigerant state (refrigerant pressure, refrigerant temperature) on the radiator 3 side.
Thereby, the pressure reduction control valve 60 can be made to function as an expansion valve. Further, by providing the working medium sealed in the sealed space 47 with the characteristics shown in FIG. 4B, when the refrigerant pressure in the high-pressure space 46 becomes equal to or higher than a predetermined pressure (Pr) that requires relief. The movable body 50 can be displaced in the valve opening direction against the working medium sealed in the sealed space.

Therefore, according to such a configuration, if the refrigerant pressure reaching the pressure control device 5 is lower than the predetermined pressure Pr, as shown in FIG.
Since the zero is not moved, the lift amount of the valve body 57 is adjusted by the bellows 63 in accordance with the refrigerant state (refrigerant pressure, refrigerant temperature) on the radiator side, whereby the refrigerant flowing out of the radiator 3 is depressurized. It is expanded and supplied to the evaporator 6.

On the other hand, when the refrigerant pressure reaching the pressure control device 5 becomes equal to or higher than the predetermined pressure Pr, FIG.
As shown in FIG. 7, the movable body 50 is lifted by the pressure difference between the high-pressure space 46 and the sealed space 47, and the bellows 63 is lifted, and the valve body 57 is forcibly separated from the communication hole. And a communication hole 52 is formed. Therefore, the high-pressure refrigerant flowing out of the radiator 3 can be relieved from the high-pressure space 46 to the low-pressure space 48 via the communication hole 52 and guided to the evaporator. That is, when the pressure of the high-pressure line 8 is going to rise abnormally at the start of a cycle or the like, the high-pressure refrigerant can be relieved to the low-pressure line 9 at the initial stage. Will be able to

Therefore, according to the pressure control device 5 described above, if the pressure in the high pressure line 8 is lower than the predetermined value Pr, the operation of the bellows causes the pressure reducing control valve 60 to function as an expansion valve. Is greater than or equal to the predetermined value Pr, the operation of the movable member 50 causes
0 can be made to function as a relief valve, so that the characteristic shown in FIG. 4C can be provided similarly to the above-described configuration example. There is no need to provide a separate valve.

In this configuration, the high pressure space 46
When the pressure of the high pressure space 4 becomes low,
Since the displacement of the movable member 50 in the direction in which the diameter of the movable member 50 is reduced is limited, it is possible to avoid the disadvantage that the movable member 50 is displaced more than necessary and the operating characteristics of the first bellows 63 are changed. Become like

FIGS. 7 and 8 show a fourth configuration example of the pressure control device 5. In this configuration, the pressure control device 5 includes a high-pressure space in a housing 65 configured by assembling housing members 65a and 65b. 66 and low pressure space 67
Are provided. In this example, the high pressure space 6
6 is formed by a space surrounded by one housing member 65a and the other housing member 65b,
The low-pressure space 67 is formed in one housing member 65b, and the high-pressure space 66 and the low-pressure space 67 are communicated via a communication hole 69 of a partition 68 provided in the housing member 65b.

At a portion of the housing member 65a facing the high-pressure space 66, a refrigerant inflow port 71 is formed to which a pipe 70 communicating with the high-pressure passage 4a of the internal heat exchanger 4 (communicating with the radiator side) is connected. A pipe 7 communicating with the evaporator 6 is provided at a portion of the housing member 65b facing the low-pressure space 67.
2 is formed with a refrigerant outlet 73.

The high-pressure space 66 accommodates a pressure-reducing control valve 74, which is connected to the high-pressure space 66 of the communication hole 69.
7 seated on valve seat 75 formed on the periphery of the opening facing
6 and a first bellows 77 joined to the valve body 76. This first bellows 77
Fixed to the top of the housing member 65a,
In the internal sealed space, a working medium having a characteristic of a relationship between temperature and pressure shown in FIG. 4A, that is, a refrigerant gas having a characteristic in which the pressure of the working medium increases with an increase in temperature, for example, a refrigerant gas, , Carbon dioxide (CO ₂ ) is sealed at a predetermined density.

Therefore, the bellows 77 is provided in the high-pressure space 6.
The lift amount of the valve body 76 is controlled by detecting and expanding and contracting the refrigerant state in the radiator 3, that is, the refrigerant state (refrigerant pressure, refrigerant temperature) on the radiator 3 side.
Thereby, the pressure reducing control valve 74 can function as an expansion valve.

In the first bellows 77, a second bellows 78 which contracts when the pressure in the bellows becomes equal to or higher than a predetermined pressure (Pr) is accommodated. The second bellows 78 is held by a holding member 79 fixed to the top of the housing member 65a. In the internal sealed space, the relationship between temperature and pressure is shown in FIG.
A working medium having the characteristics shown in FIG. 5A, that is, a working medium whose volume decreases when the pressure exceeds a predetermined pressure (Pr) is sealed.

Then, the density of the gas filled in the second bellows 78 is made smaller than the density of the gas filled in the first bellows 77, and the contraction rate of the second bellows 78 is reduced by the first bellows. It is set to be larger than the contraction rate of 77.

Therefore, in such a configuration,
If the refrigerant pressure reaching the pressure control device 5 is lower than the predetermined pressure Pr, the pressure transmitted through the working medium sealed in the first bellows 77 is also lower than Pr. Since the second bellows 78 does not contract as shown in FIG. 7, the lift amount of the valve body is changed by the first bellows 77 according to the refrigerant state (refrigerant pressure, refrigerant temperature) on the radiator side. Is adjusted, whereby the refrigerant flowing out of the radiator 3 is decompressed and expanded and supplied to the evaporator 6.

On the other hand, when the refrigerant pressure reaching the pressure control device 5 becomes equal to or higher than the predetermined pressure Pr, the pressure propagated through the working medium sealed in the first bellows 77 also becomes equal to or higher than Pr. Therefore, as shown in FIG. 8, the second bellows 78 shrinks, and the density of the sealed gas sealed in the second bellows 78 is smaller than the density of the sealed gas sealed in the first bellows 77. Is set to be smaller, the contracted volume of the second bellows 78 is larger than the contracted volume of the first bellows 77, and the first bellows 77 is attached to the bellows by the contracted volume difference. In order to maintain the pressure difference between the inside and outside, the contraction further occurs.

Therefore, the valve body 76 is forcibly separated from the communication hole 69 by the contraction of the first bellows 77, and the valve body 7
6 and the communication hole 69 will form a gap,
The high-pressure refrigerant flowing out of the radiator 3 is relieved from the high-pressure space 66 to the low-pressure space 67 via the communication hole 69, and can be guided to the evaporator side. That is, when the pressure of the high-pressure line 8 is going to rise abnormally at the start of a cycle or the like, the high-pressure refrigerant can be relieved to the low-pressure line 9 at the initial stage. Will be able to

Therefore, according to the pressure control device 5 described above, when the pressure in the high pressure line 8 is lower than the predetermined value Pr, the pressure reducing valve 74 is operated by the operation of the first bellows 77.
If the pressure in the high pressure line 8 is equal to or higher than the predetermined pressure Pr, the second bellows 78 causes the first bellows 77 to largely contract, and the pressure reducing control valve 74 functions as a relief valve. 4C, it is possible to provide the characteristic shown in FIG. 4C, similarly to the above-described configuration example. For this reason, it is necessary to separately provide a relief valve conventionally required as a separate member. Disappears.

Although the bellows 25, 26, 43, 63, 77, and 78 are used as the responsive members in the above-described configurations, the same effect can be obtained by replacing the diaphragm with a diaphragm. .

[0055]

As described above, in the vapor compression refrigeration cycle in which the pressure of the high pressure line can exceed the critical pressure of the refrigerant, the pressure control device used in this cycle is connected to the refrigerant flow communicating with the radiator side. A housing having a refrigerant outlet communicating with the inlet and the evaporator side, a valve body for changing a communication state between the refrigerant inlet side and the refrigerant outlet side, and a valve body connected to the valve body in the housing and a radiator side A first responsive member that controls the lift amount of the valve body by sensing and operating the refrigerant state of the first responsive member, and is provided in the same operating direction as the first responsive member, and senses the refrigerant pressure on the radiator side. And a second responsive member that forcibly lifts the valve element when the pressure on the radiator side is equal to or higher than a predetermined pressure, so that the pressure of the high-pressure line is equal to or higher than a predetermined value. Until pressure is reached, a second The moving member does not operate, only the first responding member operates according to the state of the refrigerant on the radiator side, the lift amount of the valve body is controlled, and the refrigerant in the high pressure line is decompressed and expanded, and the pressure in the high pressure line is reduced. When the pressure reaches a predetermined pressure or more, the second responsive member operates to forcibly open the valve body, and the refrigerant in the high pressure line can be relieved to the evaporator side. It is possible to provide both the function of decompressing and expanding the refrigerant and the function of relieving the high-pressure refrigerant to the evaporator side, and it is possible to provide a refrigeration cycle that does not require a separate relief valve.

Here, the second responsive member is constituted by connecting a bellows filled with a working medium having a characteristic that the operating pressure becomes substantially constant with respect to the change of the refrigerant temperature in series to the first responsive member. Then, when the high pressure line reaches a predetermined pressure or more, the bellows contracts and the valve body can be forcibly lifted, and the second responsive member is linked with the refrigerant pressure on the radiator side. If the housing is provided with an expansion and contraction mechanism that expands when the changing refrigerant temperature becomes equal to or higher than the temperature corresponding to the predetermined pressure, and the first response member is displaced as the housing expands and contracts. When the pressure in the high pressure line reaches a predetermined value or more, the case can be extended to forcibly lift the valve body, and the pressure control device has a function of forcibly relieving the refrigerant in the high pressure line. So that it is Rukoto.

Further, a movable body is provided for displacing the second responsive member together with the first responsive member in the movable direction of the valve body, and the refrigerant pressure on the radiator acts on the movable body in the valve opening direction to release the heat. When the pressure of the high-pressure line reaches a predetermined value or more, the movable body is actuated and the valve body is displaced when the pressure of the high pressure line reaches a predetermined value or more. The pressure control device can be forcibly lifted, and can have a function of forcibly relieving the refrigerant in the high-pressure line.

In a vapor compression refrigeration cycle in which the pressure of the high pressure line can exceed the critical pressure of the refrigerant, a pressure control device used in this cycle is provided at the refrigerant inlet and evaporator side communicating with the radiator. A housing having a refrigerant outlet communicating therewith, a valve body for changing a communication state between the refrigerant inlet side and the refrigerant outlet side, and a first working medium sealed with the valve body in the housing; A first responding member having a first closed space and changing a volume of the first closed space in accordance with a refrigerant state on a radiator side to control a lift amount of the valve body;
Is provided in the closed space, and a second working medium is sealed therein. When the pressure of the first closed space is equal to or higher than a predetermined pressure, the volume of the second closed space is increased. If the second working medium is set to have a lower density than the first working medium, the pressure of the high-pressure line is reduced to a predetermined pressure. Until the second response member is reached, the second response member does not operate, only the first response member operates according to the state of the refrigerant on the radiator side, the lift amount of the valve body is controlled, and the refrigerant in the high pressure line is decompressed and expanded. That is, when the pressure of the high pressure line reaches a predetermined value or more, the second responsive member contracts, and the contracted volume of the second responsive member becomes larger than the contracted volume of the first responsive member. Therefore, the first response member is further accommodated by the difference in the contracted volumes. Is not forced to lift the valve body,
The refrigerant in the high pressure line can be relieved. That is, the pressure control device can have both the function of decompressing and expanding the refrigerant and the function of relieving the high-pressure refrigerant to the evaporator side, so that it is possible to provide a refrigeration cycle that does not require a separate relief valve. become.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a refrigeration cycle according to the present invention.

FIG. 2 is a cross-sectional view showing a first configuration example of the pressure control device of the refrigeration cycle according to FIG. 1 and showing a state where the pressure control device functions as an expansion valve.

FIG. 3 is a cross-sectional view illustrating a first configuration example of the pressure control device of the refrigeration cycle according to FIG. 1, and illustrating a state where the pressure control device functions as a relief valve.

FIG. 4 is a diagram showing characteristics of a pressure control device, and FIG. 4 (a) is a diagram showing characteristics of a first response member;
FIG. 4B is a diagram showing characteristics of the second response member, and FIG.
(C) is a diagram showing characteristics of the entire pressure control device.

5 shows a second configuration example of the pressure control device of the refrigeration cycle according to FIG. 1, and FIG. 5 (a) is a cross-sectional view showing a state where the pressure control device functions as an expansion valve; 5 (b)
FIG. 3 is a cross-sectional view showing a state in which it functions as a relief valve.

6 shows a third configuration example of the pressure control device of the refrigeration cycle according to FIG. 1, and FIG. 6 (a) is a cross-sectional view showing a state in which the pressure control device functions as an expansion valve; 6 (b)
FIG. 3 is a cross-sectional view showing a state in which it functions as a relief valve.

FIG. 7 is a sectional view showing a fourth configuration example of the pressure control device of the refrigeration cycle according to FIG. 1 and showing a state in which the pressure control device functions as an expansion valve.

FIG. 8 is a cross-sectional view showing a fourth configuration example of the pressure control device of the refrigeration cycle according to FIG. 1 and showing a state where the pressure control device functions as a relief valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigeration cycle 2 Compressor 3 Radiator 5 Pressure control device 6 Evaporator 8 Low pressure line 9 High pressure line 24, 42, 57, 76 Valve body 10, 31, 45, 65 Housing 19, 37, 54, 71 Refrigerant inlet 21 , 39, 56, 73 Refrigerant outlet 25, 26, 43, 63, 77, 78 Bellows 30 Connecting member 44 Telescopic mechanism 50 Movable body

Claims (8)

[Claims] 1. A compressor for compressing a refrigerant to increase the pressure of the compressed refrigerant according to operating conditions to a pressure higher than a critical pressure, a radiator for cooling the refrigerant compressed by the compressor, and cooling by the radiator. A refrigeration cycle including at least a pressure control device that decompresses and expands the compressed refrigerant and an evaporator that evaporates the refrigerant flowing out of the pressure control device, wherein the pressure control device communicates with a radiator side A housing having a refrigerant inflow port communicating with the refrigerant inflow port and the evaporator side; a valve element for changing a communication state between the refrigerant inflow side and the refrigerant outflow side; and the valve element in the housing. A first responsive member for controlling the lift amount of the valve body by sensing and operating the refrigerant state on the radiator side, and provided in the same operating direction as the first responsive member,
A second responsive member that operates by sensing the refrigerant pressure on the radiator side and forcibly lifts the valve body when the refrigerant pressure on the radiator side is equal to or higher than a predetermined pressure. A refrigeration cycle characterized by being performed. 2. The second responsive member is connected in series to the first responsive member with a bellows filled with a working medium having a characteristic that an operating pressure is substantially constant with respect to a change in refrigerant temperature. The refrigeration cycle according to claim 1, wherein the refrigeration cycle is configured. 3. The housing according to claim 2, wherein the second responsive member has a mechanism in the housing for extending when the refrigerant temperature that changes in conjunction with the refrigerant pressure on the radiator side is equal to or higher than the temperature corresponding to the predetermined pressure. 2. The refrigeration cycle according to claim 1, wherein the first response member is displaced in accordance with expansion and contraction of the housing. 4. The second responsive member is provided with a movable body that is displaced together with the first responsive member in a movable direction of the valve body, and the movable body is provided with a refrigerant pressure on the radiator side in a valve opening direction. The refrigeration cycle according to claim 1, wherein the movable body is displaced in a valve opening direction when the pressure on the radiator side is equal to or higher than a predetermined pressure. 5. A compressor for compressing the refrigerant to increase the pressure of the compressed refrigerant according to operating conditions above a critical pressure, a radiator for cooling the refrigerant compressed by the compressor, and cooling by the radiator. A refrigeration cycle including at least a pressure control device that decompresses and expands the compressed refrigerant and an evaporator that evaporates the refrigerant flowing out of the pressure control device, wherein the pressure control device communicates with a radiator side A housing having a refrigerant inflow port communicating with the refrigerant inflow port and the evaporator side; a valve element for changing a communication state between the refrigerant inflow side and the refrigerant outflow side; and the valve element in the housing. A first closed space in which the first working medium is sealed, and a volume of the first closed space is changed in accordance with a refrigerant state on the radiator side to lift the valve body. The controls one
And a second closed space, which is disposed in the first closed space and in which a second working medium is sealed, and has a capacity of the second closed space that is equal to the pressure of the first closed space. And a second responsive member that reduces when the pressure is equal to or higher than a predetermined pressure, wherein the density of the second working medium is made smaller than the density of the first working medium. Characterized refrigeration cycle. 6. The second responsive member is constituted by a bellows or a diaphragm enclosing the second working medium having a characteristic that an operating pressure is substantially constant with respect to a change in refrigerant temperature. The refrigeration cycle according to claim 5, wherein 7. The refrigeration cycle according to claim 1, wherein the first response member is constituted by a bellows or a diaphragm in which the refrigerant or a working medium having characteristics equivalent to the refrigerant is sealed. . 8. The method according to claim 1, wherein the refrigerant is carbon dioxide.
Or the refrigeration cycle of 5.