JP2001108310A - Pressure control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit the reducing of the pressure in a sealed space, into which a gas is sealed, and permit the optimum high pressure control. SOLUTION: The pressure of a gas, sealed into the sealed space of an expansion device, can be controlled by a pressure regulating means and, therefore, the amount of movement of a displacement member, displaced by a pressure difference between that of a sealed gas and that of a refrigerant in a high- pressure chamber, whereby a delicate high-pressure control of the expansion device can be carried out. The pressure regulating means is a temperature regulating means provided so as to be contacted with the sealed space whereby it can be a temperature regulating means for heating a gas sealed space, communicating with the sealed space, and the gas sealed space while a heater, a Peltier element or the like can be considered as the temperature regulating means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refrigeration cycle in which carbon dioxide is used as a refrigerant, the refrigerant is compressed to a supercritical region at a high load, and the high pressure changes in a region below a critical point at a low load. The present invention relates to a pressure control device that is used and adjusts a valve opening degree by a high-pressure refrigerant temperature and a refrigerant pressure to reduce a pressure of a refrigerant flowing into an evaporator.

[0002]

2. Description of the Related Art In a pressure control valve disclosed in Japanese Patent Application Laid-Open No. 9-264622, a displacement member forming a sealed space is displaced when a pressure in an upstream space becomes larger than a pressure in the sealed space by a predetermined value. The valve body opens the valve port when the displacement member is displaced, and connects the upstream space and the downstream space. The temperature of the refrigerant is 0 in the closed space.
Since the refrigerant is sealed at a density ranging from the saturated liquid density at ℃ to the saturated liquid density at the critical point of the refrigerant, the characteristics of the refrigerant pressure and the refrigerant temperature in the closed space are determined by the optimal control line ηmax.
Since the pressure control valve raises the outlet pressure of the radiator to a pressure along the optimal control line and then opens the valve port, the outlet pressure of the radiator and the radiator The outlet side temperature can be controlled along the optimal control line.

[0003]

The above reference includes 450
Although Kg / m ³ ~900Kg / m gas at a density of ³ have been described to be encapsulated, when mounting the pressure control valve itself refrigeration cycle, the refrigerant is not filled in the refrigeration cycle, Since the external pressure is 1 atm with respect to the internal pressure of the above-mentioned displacement member, for example, the diaphragm or the bellows, the pressure difference is extremely large, and the diaphragm or the bellows is damaged before the refrigerant is filled in the refrigeration cycle, and the mounting operation is difficult. Has occurred.

[0004] Therefore, an object of the present invention is to provide a pressure control device capable of reducing the pressure in a sealed space in which gas is sealed and enabling the most appropriate high-pressure control.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a high-pressure chamber provided upstream of an evaporator, to which a high-pressure refrigerant is supplied, and a gas having a predetermined density disposed in the high-pressure chamber. And a displacement member that defines the closed space and is displaceable so that an optimum coefficient of performance is obtained by the temperature and pressure of the refrigerant in the high-pressure chamber, and the high-pressure chamber is attached to the displacement member. And a valve for opening and closing a passage from the evaporator to the evaporator. The pressure control device includes pressure adjusting means for adjusting the pressure of the gas sealed in the closed space.

Thus, the pressure of the gas sealed in the closed space of the expansion device can be adjusted by the pressure adjusting means.
Since the amount of movement of the displacement member that is displaced by the differential pressure between the sealed gas and the refrigerant pressure in the high-pressure chamber can be finely adjusted, it is possible to execute fine high-pressure control of the expansion device. In addition, since the density of the gas sealed in the sealed space can be reduced, the manufacturing process of the expansion device can be simplified.

[0007] The gas density of the gas sealed in the closed space is a predetermined value lower than the gas density at which the optimum coefficient of performance is obtained. Thereby, according to the present invention, the density of the gas sealed in the closed space can be reduced at a predetermined rate, and the pressure difference between the gas and the outside air can be reduced, so that the mountability of the displacement member can be improved, In addition, since the pressure adjusting means for correcting the pressure shortage of the gas sealed in the closed space is provided, the state in which the gas of the appropriate density is sealed and the displacement state of the displacement member can be matched, so that the mountability of the expansion device is improved. Optimum high-pressure control can be performed while improving the pressure.

Preferably, the pressure adjusting means is a temperature adjusting means provided in contact with the closed space, and a gas filled space communicating with the closed space, and a gas filled in the gas filled space. It may be a temperature adjusting means for adjusting the temperature. Thus, the gas in the closed space can be expanded or contracted by heating or cooling the gas in the closed space by the temperature adjusting means, so that the pressure of the gas in the closed space can be adjusted to an appropriate value and, for example, cooling can be performed. The pressure of the gas in the closed space can be changed in accordance with the change in the load.

The temperature adjusting means is preferably a ceramic heater, a Peltier element, or the like. When the gas density in the closed space is low, the expansion / contraction of the gas can be controlled by changing the amount of current supplied to a normal heater typified by a ceramic heater, and the cost is low. In the case of the Peltier element, there is an advantage. In the case of the Peltier element, it is easy to switch between cooling and heating by switching the direction of current supply, and since the amount of heat radiation and the amount of heat absorbed can be controlled by changing the amount of current supply, fine pressure control is performed There is an advantage that can be.

Further, the pressure adjusting means may be a moving means for moving a displacement member defining the closed space. Thus, the position of the valve member provided on the displacement member can be changed with respect to the valve seat by changing the position of the displacement member by the moving means. Can be adjusted.

[0011] The moving means may slidably define one side surface of the high-pressure space and have the displacement member fixed to the high-pressure space side, and one end contacting the slide table. And a driving means for moving the slide table in the axial direction.

Further, the driving means includes a screw portion formed around the rod, a screw hole formed in the case, and a motor actuator for rotating the rod, and the motor actuator rotates the rod. With this, the rod can move in the axial direction by the screw portion formed in the rod and the screw hole into which the screw portion is screwed, and the slide can be moved to the high pressure side. Can be approached. Also, when moving the rod away from the slide, the slide comes into contact with the rod due to the pressure in the high pressure space.
The valve body can be separated from the valve seat.

Further, it is desirable that the pressure adjusting means controls the degree of supercooling according to a cooling load. Thus, when the cooling load is large, control is performed so that the degree of supercooling is increased, and when the cooling load is small, control is performed so that the degree of superheating is reduced, and control corresponding to the cooling load is performed.

Preferably, the refrigerant and the gas sealed in the closed space are carbon dioxide.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

A refrigeration cycle 1 shown in FIG. 1 uses carbon dioxide as a refrigerant, and includes at least a compressor 2, a heat exchanger 3 for radiating heat, a high-pressure heat exchanger 5 of an internal heat exchanger 4, an expansion device 6, an evaporator 7, This is a closed circuit formed by connecting an accumulator 8 and a low-pressure side heat exchanger 9 of the internal heat exchanger 4 in series with a pipe.

In the refrigerating cycle 1, the compressor 2 compresses the sucked refrigerant (ab) and discharges it to the heat-radiating heat exchanger 3, as shown in the Mollier diagram of FIG. In the heat radiating heat exchanger 3, the refrigerant compressed by the compressor 2 is cooled by heat exchange with air passing through the heat radiating heat exchanger 3, and further cooled in the heat radiating heat exchanger 3. The cooled refrigerant passes through the high-pressure side heat exchanger 5 of the internal heat exchanger 4 and exchanges heat with the low-pressure gas-phase refrigerant passing through the low-pressure side heat exchanger 9 to be cooled (ac). Go to

As shown in FIG. 2, the expansion device 6 includes a case 20, a high pressure space 22 defined inside the case,
Piping 41 from the high-pressure side heat exchanger 5 of the internal heat exchanger 4
Hole 21 connected to the evaporator 7, an outflow hole 23 connected to a pipe 42 leading to the evaporator 7, a valve seat 24 formed in a peripheral edge of the outflow hole 23 on the high pressure space side, and positions of the valve seat 24. Valve body 25 that opens and closes the outflow hole 23 according to the relationship
A displacement member 27 in which a gas having a predetermined density is sealed in the closed space 28; a plate portion 30 formed at an end of the displacement member 27; A rod 26 fixed to the base 30 and provided with the valve body 25 at the tip thereof, and provided between the plate portion 30 and the case 20 to connect the plate portion 30 to the valve seat 24.
It is constituted by a spring 29 biased to the side. Further, the expansion device 6 according to the present invention includes the closed space 28.
A heater 31 is provided as pressure adjusting means for adjusting the pressure of the gas sealed therein. The displacement member 2
Reference numeral 7 uses a bellows in the present embodiment, but a diaphragm may be used.

With the above arrangement, when the refrigerant pressure in the high-pressure space 22 is larger than the sum of the pressure of the gas sealed in the closed space 28 and the urging force of the spring 29, the expansion device 6 has the above displacement. Since the member 27 contracts, the valve body 2
5 is separated from the valve seat 24 and opens the outflow hole 23, so that the high-pressure refrigerant flows out to the evaporator 7 side. In addition, high pressure space 2
When the pressure of the refrigerant in the second space 2 is smaller than the sum of the pressure of the gas sealed in the closed space 28 and the urging force of the spring 29, the displacement member 27 expands, so that the valve body 25 is seated on the valve seat 24. Then, the outflow hole 23 is closed. Further, even when the refrigerant temperature in the high-pressure space 22 is high, the gas in the closed space 28 expands, so that the valve body 25 moves in a direction to close the outflow hole 23, and the best performance with respect to the refrigerant temperature is obtained. The valve body 25 is controlled so that the pressure becomes a high pressure at which a coefficient is obtained.

In the expansion device 6, the throttle effect is adjusted by the valve opening between the valve body 25 and the valve seat 24, whereby the high-pressure refrigerant is reduced in pressure to the gas-liquid two-phase region and expanded ( cd). Then, in the evaporator 7, heat exchange is performed with the air passing through the evaporator 7, and the refrigerant absorbs heat and evaporates (de). And
The refrigerant flowing out of the evaporator 7 flows into the accumulator 8, where it is separated into a liquid phase component and a gas phase component, and the liquid phase component is accommodated and only the gas phase component flows out. The gas phase component flowing out of the accumulator 8 passes through the low pressure side heat exchanger 9 of the internal heat exchanger 4, exchanges heat with the high temperature refrigerant passing through the high pressure side heat exchanger 5, is superheated, and is sucked into the compressor 2. Is done.

With the above configuration, the refrigeration cycle 1 that absorbs heat from the air passing through the evaporator 7 and radiates heat to the air passing through the heat-radiating heat exchanger 3 is configured. In this refrigeration cycle 1, the gas sealed in the displacement member 27 of the expansion device 6 is, as shown in FIGS. 7 and 8, a certain refrigerant temperature TH and a high-pressure pressure at which the maximum coefficient of performance is obtained at this refrigerant temperature TH. Optimal control line η showing the relationship with PH
m, the displacement member 27 is desirably sealed under a condition capable of being displaced. Normally, a refrigerant similar to the refrigerant circulating in the refrigeration cycle 1, in this embodiment, carbon dioxide is filled with a predetermined sealing density λ ( It is desirable to encapsulate at about 700 kg / m ³ ).

However, before the expansion device 6 is mounted on the refrigeration cycle 1, the high-pressure space 22 is at atmospheric pressure, so that the pressure difference between the high-pressure space 22 and the gas sealed in the closed space 28 is large, and the valve body 25 Since the valve seat 24 is pressed by a large force, the valve seat 24 is damaged and the rod 26
And the plate portion 30 is damaged or deformed. For this reason, in the present invention, the density of the gas sealed in the sealed space 28 is reduced as much as possible. In the sealed space 28, the sealed density λ ′ (600 kg / m ³ ) of gas.

As a result, as shown in FIGS. 7 and 8, when the filling density λ ′ is filled with respect to the optimum control line ηm based on the filling density λ, the high pressure PH with respect to the refrigerant temperature TH is represented by ηr. Characteristic line. For this reason,
For example, when the refrigerant temperature TH1 in the high-pressure space 22 is:
Although the high pressure is Pm at an appropriate filling density γ, the corresponding high pressure is Pm due to the low gas filling density in the present application.
m '. Therefore, in order to obtain the high pressure Pm, the high pressure Pm can be obtained by heating the sealed gas by the heater 31 and raising the temperature of the sealed gas from TH1 to TH2. As described above, by heating a gas having a low encapsulation density γ ′, the characteristic line ηr can be matched with the optimal characteristic line ηm for an appropriate encapsulation density γ.
In FIG. 8, LV indicates a saturated liquid line, and VG indicates a saturated vapor line.

The control of the refrigeration cycle 1 having the above configuration is executed by the control unit (C / U) 16. The control unit 16 receives various data signals, specifically, the high pressure PH on the inflow side of the expansion device 6 and the refrigerant temperature T.
H, the outside air temperature Ta, the engine rotation speed Ne of the traveling engine (not shown), and the evaporator outlet temperature Te from the temperature sensor 14 disposed near the downstream side of the evaporator 7.
The input signal is input through the input unit (I / U) 15 and further the setting signal from the operation panel (C / P) 17 is input and processed by a predetermined program.
/ U) 18 to output a control signal.
In this embodiment, the output unit 18 outputs the compressor control signal Sc and the control signal Sv to the heater 31 of the expansion device 6.

The control of the heater as the pressure control means 31 of the expansion device 6 executed by the control unit 16 is shown, for example, in the flowchart of FIG. The pressure adjustment control shown in this flowchart is executed at predetermined intervals from a main control routine for performing main control of the air conditioner, which is executed by the control unit 16, and is executed from step 100.

In the pressure adjustment control started from the step 100, various data,
For example, the high pressure PH of the refrigerant and the refrigerant temperature TH are input. Then, in step 120, the refrigerant temperature T
H to the target high pressure P based on the optimal control line ηm in FIG.
m is calculated. Then, in step 130, the target Pm is compared with the actual high pressure PH, and if the target high pressure Pm is larger than the actual high pressure PH,
Proceeding to step 140, the heater as the pressure adjusting means 31 is turned on, and the energization of the heater in step 140 is continued until the actual high pressure PH becomes equal to the target high pressure Pm in the determination in step 150. When the actual high pressure PH coincides with the target high pressure Pm in the determination of the above, the routine proceeds to step 160, the heater is turned off, and the routine returns from step 170 to the main control routine. In addition, in the determination of step 130,
If the actual high pressure PH is higher than the target high pressure Pm, the routine proceeds to step 160, where the heater 31 is turned off.

When a Peltier element is used as the pressure adjusting means 31, in step 140 electricity is supplied so that the Peltier element releases heat to the gas in the closed space 28. In step 160, the Peltier element is energized. To stop the power supply to the
In the judgment of 0, the actual high pressure PH is equal to the target high pressure P
When the pressure is higher than m, a step of positively supplying current to cool the gas in the closed space 28 may be provided. Thus, the valve element 25 can be controlled finely.

Furthermore, in the above-described flowchart, the heater is controlled so that the actual high pressure PH coincides with the target high pressure Pm. However, the control line ηr and the optimum control line ηm when the gas density is low are Temperature difference Δ
T may be obtained, and the energization control to the heater may be performed so that ΔT becomes zero.

The flowchart shown in FIG. 6 shows pressure adjustment control according to another embodiment. This pressure adjustment control can adjust the pressure of the gas sealed in the closed space 28 as necessary, regardless of the density of the gas sealed in the closed space 28.

In the pressure adjustment control started from step 200, in step 210, it is determined whether or not the refrigeration cycle 1 is in the early stage of startup, and if it is determined that it is in the early stage of startup, the process proceeds to step 250. Then, the heater is turned off. When a Peltier element is used as the pressure adjusting means 31, the closed space 28 is connected to the Peltier element.
An electric current may be caused to flow in a direction for actively cooling the gas sealed therein. As a result, the power supply to the heater is passively turned off so as not to increase the pressure of the gas in the closed space 28, and the gas is cooled positively by the Peltier element to lower the pressure, and the expansion device 6 The valve body 25 can be controlled so as to open the outflow hole 23, so that the compressor load at the time of startup can be reduced.

If it is determined in step 210 that the starting is not in the initial stage, the process proceeds to step 220 to determine the rotational speed Ne of the traveling engine of the vehicle (not shown). If it is determined in step 220 that the engine rotation speed Ne is within a predetermined range (α1 <Ne <α2), it is determined that the engine is in an idle state, and it is determined that it is necessary to secure cooling power. Then, the heater as the temperature adjusting means 31 is turned on, or an electric current is supplied to the Peltier element in a direction for heating the gas sealed in the closed space 28 so that the valve body 25 of the expansion device 6 closes the outlet hole 23. Since the refrigeration cycle 1 is moved, the high pressure of the refrigeration cycle 1 increases, and the cooling capacity increases. The above α
1 is 1000 rpm and α2 is 1800 rpm.

If it is determined in step 220 that the engine rotation speed Ne is equal to or higher than the predetermined rotation speed α2, the process proceeds to step 230 to determine whether or not the outside air temperature Ta is higher than a predetermined value β (for example, 25 ° C.). Is determined.
In this determination, when the outside air temperature Ta is higher than the predetermined value β, it is desirable to increase the high pressure assuming that the cooling load is large.
A current is supplied so that the N or Peltier element dissipates heat. As a result, the gas in the closed space 28 can be heated and expanded, so that the valve body 25 moves in the direction to close the outflow hole 23, the high pressure increases, and the cooling capacity improves. Then, the process returns from step 260 to the main control routine.

Thus, when the engine speed Ne is equal to or higher than the predetermined value and the driving force of the compressor is sufficient, when the outside air temperature Ta is high and the cooling load needs to be increased, the high pressure is further increased. Therefore, the degree of supercooling increases, and the cooling capacity of the evaporator 7 can be increased.

Further, FIGS. 3 and 4 disclose expansion devices 6 according to the second and third embodiments of the present invention, which will be described below. The same reference numerals are given to the same portions or portions having the same effects as those of the expansion device according to the above, and the description thereof is omitted.

The expansion device 6 shown in FIG. 3 has a communication pipe 34 having a communication passage 35 communicating with the closed space 28.
A gas filled space 33 communicating with the closed space 28 through the communication passage 35; and an outer case 32 defining the gas filled space 33.
The heater or Peltier element as the
It is provided in. Thereby, after the expansion device 6 is mounted on the refrigeration cycle 1, the outer case 32 is mounted on the case 20 via the communication pipe 34 so that the inside of the gas filled space 33 and the closed space 28 are communicated. Then, the gas in the gas filled space 33 can be filled in the closed space 28. by this,
The mounting workability of the expansion device 6 can be further improved. Also in this embodiment, the above-described pressure adjustment control can be performed.

In the expansion device 6 according to the third embodiment shown in FIG. 4, the position of the valve body 25 accompanying the reduction of the density of the gas sealed in the closed space 28 is changed by the position of the bellows 27 itself. The moving table 40 to which the bellows 27 is fixed is used as moving means.
And a rod 41 for moving the movable table 40 in the direction of movement of the valve element 25, and an actuator 42 for moving the rod 41. A male screw that is screwed with a female screw formed in the case 20 is cut on the outer periphery of the rod 41. By rotating the rod 41 with the actuator 42, the rod 41 moves back and forth in the axial direction. It is possible.

In this configuration, the same control as the pressure adjustment control is performed by setting the “heater ON” in steps 140 and 240 in the direction in which the slide table 41 is pushed out (the valve body 2).
5 is moved in the direction of closing the outflow hole 23, and the “heater OFF” in Steps 160 and 250 is replaced by the direction in which the slide 41 is retracted (the direction in which the valve 25 closes the outflow hole 23). ) Can be executed by switching to “actuator reverse”. Thus, the same effects as those of the expansion devices of the first and second embodiments can be obtained also in the expansion device according to the third embodiment.

[0038]

As described above, according to the present invention, the pressure of the refrigerant sealed in the closed space of the expansion device is adjusted by adjusting the heating amount of the sealed refrigerant, or by heating or cooling. Therefore, appropriate high-pressure control of the expansion device can be performed, and a desired cooling capacity can be easily obtained.

Thus, the density of the refrigerant sealed in the closed space of the expansion device can be reduced, so that the pressure difference between the sealed gas and the outside air can be reduced, and the expansion device can be damaged before being mounted on the refrigeration cycle. , Deformation can be prevented.

Further, by heating or heating / cooling,
Since the pressure of the gas in the closed space can be adjusted, the amount of gas to be charged can be roughly set, so that the work of mounting the expansion device on the refrigeration cycle can be facilitated.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing a configuration of the expansion device according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a configuration of an expansion device according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a configuration of an expansion device according to a third embodiment of the present invention.

FIG. 5 is a flowchart illustrating an example of temperature adjustment control.

FIG. 6 is a flowchart showing another embodiment of the temperature adjustment control.

FIG. 7 shows an optimal control line ηm showing the relationship between the refrigerant temperature and the refrigerant pressure at which the maximum coefficient of performance can be obtained, and the relationship between the refrigerant temperature and the refrigerant pressure when the gas with reduced encapsulation density is enclosed. FIG. 7 is a characteristic diagram shown.

FIG. 8 is an example of a Mollier diagram of the refrigeration cycle of the present invention and a characteristic diagram showing an optimum control line and the like.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigeration cycle 2 Compressor 3 Radiation heat exchanger 4 Internal heat exchanger 5 High pressure side heat exchanger 6 Expansion device 7 Evaporator 8 Accumulator 9 Low pressure side heat exchanger 10,12 Pressure sensor 11,13,14 Temperature sensor 20 Case 21 Inflow hole 22 High pressure space 23 Outflow hole 24 Valve seat 25 Valve body 26 Rod 28 Closed space 31 Temperature control means (Heater, Peltier element) 32 Outer case 33 Gas filled space 34 Communication pipe 35 Communication path 40 Slide table 41 Rod 42 Actuator

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Yuji Kawamura 39, Higashihara, Chiyo-ji, Odai-gun, Osato-gun, Saitama Prefecture Inside of Xexel Konan Plant (72) Inventor Shunji Muta 39, Higashihara, Chiyo-ji, Konan-cho, Osato-gun, Saitama Prefecture Address: Inside the Xexel Gangnam Plant (72) Inventor Kenji Iijima 39, Higashihara, Chiyo-ji, Odai-gun, Osato-gun, Saitama Prefecture Inside of the Zexxel Gangnam Plant (72) Inventor: Sakae Hayashi 39, Chiyo-ji, Higashihara, Konan-cho, Osato-gun, Saitama Prefecture Address: Inside the Xexel Gangnam Plant (72) Inventor Hiroshi Kanai 39, Higashihara, Chiyo-ji, Odai-gun, Osato-gun, Saitama 39 Inventor: Akihiko Takano 39, Higashihara, Chiyo-ji, Konan-cho, Osato-gun, Saitama Address Zexel Gangnam Plant

Claims (8)

[Claims] 1. A high-pressure chamber provided upstream of an evaporator and supplied with a high-pressure refrigerant, a sealed space provided in the high-pressure chamber and filled with a gas of a predetermined density, and A displacement member that is defined and is displaceable so that an optimum coefficient of performance is obtained by the temperature and pressure of the refrigerant in the high-pressure chamber; and a valve that is attached to the displacement member and opens and closes a passage from the high-pressure chamber to the evaporator. A pressure control device comprising: a body; and a pressure control device provided with pressure adjustment means for adjusting a pressure of the gas sealed in the closed space. 2. The pressure control device according to claim 1, wherein the gas density of the gas sealed in the closed space is lower by a predetermined value than the gas density at which the optimum coefficient of performance is obtained. 3. The pressure control device according to claim 1, wherein the pressure adjustment unit is a temperature adjustment unit provided in contact with the closed space. 4. The pressure adjusting means according to claim 1, wherein said pressure adjusting means is a gas sealed space communicating with said closed space, and a temperature adjusting means for adjusting the temperature of the gas sealed in said gas sealed space. Or the pressure controller according to 2. 5. The pressure control device according to claim 3, wherein said temperature adjusting means is a heater. 6. The pressure control device according to claim 3, wherein said temperature adjusting means is a Peltier element. 7. The pressure adjusting device according to claim 1, wherein the pressure adjusting device is a moving device that moves an entire displacement member defining the closed space with respect to a passage opened and closed by the valve element. Pressure control device. 8. The method according to claim 1, wherein the refrigerant and the gas sealed in the closed space are carbon dioxide.
8. The pressure control device according to any one of 7.