JPH0424215Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The invention uses a Gifford-McMahon cycle (Gifford-McMahon cycle) in which paired expansion chambers are expanded and contracted alternately.
This invention relates to a timing valve for a refrigeration system that can be suitably used in a cryogenic refrigeration system operated by Mcmahon Cycle.

[Prior Art] Timing valves for switching gas flow paths in small cryogenic refrigeration systems using the Gifford-McMahon cycle are generally rotary valves driven by motor rotation or slide valves driven by cams. However, such a valve requires a large-scale driving mechanism, making the entire valve large. In addition, since there are many sliding parts, energy loss due to friction and performance deterioration due to wear are unavoidable. In order to deal with such inconveniences, it has been considered to use an electromagnetic switching valve as a timing valve, in which the valve body is moved back and forth by an electromagnetic actuator to control gas flow.
Normal electromagnetic switching valves require a constant current to flow through the electromagnetic actuator in order to hold the valve body in the open or closed position, so there is a risk that the refrigeration performance will deteriorate due to the heat generated in the actuator. There is.

Recently, in this type of refrigeration equipment, expansion chambers are formed on both sides of vanes that perform reciprocating rotational motion, displacers that perform reciprocating linear motion, etc., and these expansion chambers are expanded along with the reciprocating motion. Alternate scaling has been developed. However, this product can expand the gas in each of the pair of expansion chambers, making it possible to significantly improve the refrigerating capacity without increasing the size. Since gas must be supplied to each expansion chamber separately, the structure of the timing valve becomes complicated, and the above-mentioned disadvantages become even more pronounced.

[Problems to be solved by the invention] The invention solves problems such as increasing the size, unavoidable energy loss due to friction, and performance deterioration due to wear. The purpose is to reliably solve the problem of reduced performance with a simple configuration.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides internal partition walls for forming a pair of supply and exhaust chambers that communicate with each expansion chamber on both sides of a high pressure chamber that communicates with the air supply system path. At the same time, a low pressure chamber communicating with the exhaust system path is installed adjacently through an outer partition wall on the side opposite to the high pressure chamber of these supply and exhaust chambers,
A valve shaft movable in the axial direction is passed through each of the inner partition walls and each of the outer partition walls, an inner valve seat is provided in the valve shaft penetration portion of each of the inner partition walls, and an inner valve seat is provided in the valve shaft penetration portion of each of the outer partition walls. An outer valve seat is provided, and a pair of inner valve bodies selectively seated on each corresponding inner valve seat is provided at a portion of the valve shaft located within each supply/discharge chamber, and a pair of inner valve bodies are selectively seated on each corresponding outer valve seat. The outer valve body of one supply/discharge chamber and the inner valve body of the other supply/discharge chamber are supported by an electromagnetic actuator, and the outer valve body of one supply/discharge chamber and the inner valve body of the other supply/discharge chamber are attached to the corresponding outer valve seats. and a first switching position where the outer valve body of the other supply/discharge chamber and an inner valve body of one supply/discharge chamber are seated on the corresponding outer valve seat and inner valve seat, respectively. The outer valve element in the seated position receives a force in the valve closing direction from the high pressure gas in the supply/discharge chamber than the inner valve body in the seated position. The pressure-receiving area of each valve body is set so that the pressure-receiving area of each valve body is larger than the force in the valve-opening direction received from the high-pressure gas in the high-pressure chamber.

[Operation] According to such a configuration, when the electromagnetic actuator is temporarily driven to move the valve shaft to the first switching position, the outer valve body of one supply/discharge chamber is seated on the corresponding outer valve seat. At the same time, the inner valve body of the other supply/discharge chamber is seated on the corresponding inner valve seat. As a result, the high-pressure gas introduced into the pressure chamber from the air supply system path is guided to the one supply and discharge chamber, and from this supply and discharge chamber to one of the expansion chambers. Further, since the other supply/discharge chamber is open to the low pressure chamber, the low pressure gas discharged from the other expansion chamber is guided to the low pressure chamber through the other supply/discharge chamber and is discharged to the exhaust system path. From this state,
When the electromagnetic actuator is temporarily driven again to move the valve shaft to the second switching position,
The outer valve body of the other supply/discharge chamber is seated on the corresponding outer valve seat, and the inner valve body of one supply/discharge chamber is seated on the corresponding inner valve seat. As a result, the high-pressure gas introduced into the pressure chamber from the air supply system path is guided to the other supply/discharge chamber, and from this supply/discharge chamber to the other expansion chamber. Further, since the one supply/discharge chamber is open to the low pressure chamber, the low pressure gas discharged from the one expansion chamber is guided to the low pressure chamber through the one supply/discharge chamber,
Exhausted into the exhaust system. Then, once the first
or the second position,
The force with which the outer valve body is biased in the valve closing direction by the high pressure gas in the supply/discharge chamber is greater than the force with which the inner valve body is biased in the opening direction by the high pressure gas in the pressure chamber. Therefore, even if the electromagnetic actuator is de-energized, each of the valve bodies is maintained at its switching position.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 is a longitudinal cross-sectional view showing the main body of the small-sized cryogenic refrigeration device, and numeral 1 in the figure is a base serving as a fixing member. The base 1 is a cylindrical body with a bottom, and has a pair of inflow and outflow ports 2 and 3 on its bottom plate 1a. One outflow/inflow port 2 is bored in the center of the bottom plate 1a, and a communication pipe 4 is airtightly fitted into the upper half of this outflow/inflow port 2 via a seal member 5 and fixed with a set screw 6. are doing. This communication pipe 4 extends upward, and a mounting disk 7 is attached to its upper end. A first regenerator 8 is placed on this mounting disc 7 and fixed with a plurality of bolts 9. The first regenerator 8 is made up of a plurality of alternately stacked heat storage elements 11 and spacers (not shown). The heat storage element 11 is a disc-shaped element made of copper or the like, and has a large number of ventilation holes 11a that penetrate vertically. The spacer is made of stainless steel wire or the like. A high temperature end (normal temperature end) 8a of the first regenerator 8 communicates with the inflow/outflow port 2 via a port 7a bored in the mounting disc 7 and the communication pipe 4, and also communicates with the inflow/outflow port 2 through the port 7b. It communicates with the chamber 10 via. Furthermore, a movable shell 12 is slidably fitted around the outer periphery of the first regenerator 8. The movable shell 12 has a cylindrical shape that fits around the outer periphery of the regenerator 8, and its end on the low temperature side is closed by a ceiling wall 12a. The top wall 12 of this movable shell 12
A first expansion chamber 13 is formed between the low temperature end 8b of the first regenerator 8 and the low temperature end 8b of the first regenerator 8. Further, a flange portion 12 is provided at the end of the movable shell 12 on the high temperature side.
b is formed, and a bottom plate 12c is attached to this flange portion 12b via a sealing member 14. A shaft hole 12d is bored in the center of the bottom plate 12c, and this shaft hole 12d is slidably fitted onto the outer periphery of the communication tube 4 via a seal member 15. Further, cushioning rubber pads 16 and 17 are fixed to the outer peripheral edge of the bottom plate 12c and the flange portion 12b. Further, a second regenerator 19 held by a casing 18 is provided around the outer periphery of the movable shell 12. Casing 18
is a cylindrical body that encloses the second regenerator 19, and its low temperature side end is connected to the inverted cup-shaped top wall 1.
8a. A second expansion chamber 21 is formed between the top wall 18a and the movable shell 12. Further, a flange portion 18b is provided on the high temperature end side of the casing 18, and this flange portion 18b is attached to the upper end opening of the base 1 via a sealing member 22. The second regenerator 19 is formed by stacking heat storage elements 23 and spacers (not shown) in multiple stages alternately, and is fixed to the casing 18 using bolts 24 . The heat storage element 23 is an annular element made of copper or the like, and has a large number of ventilation holes 23a penetrating vertically. The spacer is made of stainless steel wire or the like. In addition,
The high temperature end 19a of the second regenerator 19 communicates with the inflow/outflow port 3 via a chamber 20a, a port 12e formed in the movable shell 12, and a chamber 20b. Also, this regenerator 1
The low-temperature end 19b of No. 9 communicates with the second expansion chamber 21 via a port 18c provided in the casing 1.

Both the inflow and outflow ports 2 and 3 are connected to an air supply system path 26 or an exhaust system path 27 via a timing valve 25. Specifically, the timing valve 25 has a configuration as will be described later, and is designed to switch in the manner shown by symbols in FIG. 2. That is, at the switching position A, one of the inflow and outflow ports 2 is connected to the air supply system path 26, and the other outflow and inflow port 3 is connected to the exhaust system path 27. Also, position B
Here, one inflow/outflow port 2 is connected to the exhaust system path 27, and the other outflow/inflow port 3 is connected to the air supply system path 26. The position A and the position B are alternately switched. The air supply system path 26 is connected to a compressor 28
The high-pressure gas discharged from the discharge port 28a of the timing valve 25 is supplied to the air supply port 25a of the timing valve 25 through the cooler 29, and
The exhaust line 27 is for guiding low pressure gas discharged from the exhaust port 25b of the timing valve 25 to the intake port 28b of the compressor 28.

Here, the structure of the timing valve 25 will be explained in detail based on FIG. 1. This timing valve 2
5 has a high pressure chamber 31 communicating with the air supply system path 26. A pair of supply/discharge chambers 32A, 32B that communicate with the expansion chambers 13, 21, respectively, are provided on both sides of this high pressure chamber 31 with inner partition walls 33A, 33B.
These supply and discharge chambers 32
The low pressure chambers 34A, 34B communicating with the exhaust system path 27 are connected to the outer partition walls 35A, 35B on the side opposite to the high pressure chamber of A, 32B.
A valve shaft 36 that can move forward and backward in the axial direction is passed through each of the inner partition walls 33A, 33B and each of the outer partition walls 35A, 35B. An inner valve seat 3 is provided in the valve shaft penetrating portion of each inner partition wall 33A, 33B.
7A and 37B, respectively, and an outer valve seat 38 is provided in the valve shaft penetrating portion of each of the outer partition walls 35A and 35B.
A, 38B are provided respectively, and a pair of inner valve bodies 39A, 39B are provided at portions of the valve shaft 36 located in the supply/discharge chambers 32A, 32B, and selectively seated on the corresponding inner valve seats 37A, 37B. and a pair of outer valve bodies 41A, 41B selectively seated on the corresponding outer valve seats 38A, 38B. Each inner valve body 39A, 39B and each outer valve body 41A, 41B
is in the shape of a truncated cone, and is fixed to the valve shaft 36 with its small diameter side facing the corresponding valve seats 37A, 37B, 38A, and 38B. Then, this valve shaft 36 is connected to an electromagnetic actuator 42A,
42B, the outer valve body 4 of one supply/discharge chamber 32A
1A and the other supply/discharge chamber 32B are seated on the corresponding outer valve seat 38A and inner valve seat 37B, respectively, and the other supply/discharge chamber 32
The outer valve body 41B of B and the inner valve body 39A of one of the supply/discharge chambers 32A are moved back and forth between a second switching position B where they are seated on the corresponding outer valve seat 38B and inner valve seat 37A, respectively. . Electromagnetic actuator 4
2A, 42B are composed of electromagnets 44A, 44B fixed to the casing 43 and iron pieces 45A, 45B fixed to the end of the valve shaft 36. By selectively energizing each of the electromagnets 44A, 44B, , the valve shaft 36 can be moved forward and backward in the axial direction in an ON/OFF manner. That is, the valve shaft 36 moves from the first switching position A to the second switching position B and then stops, or conversely, moves from the second switching position B to the first switching position A at once. There is no possibility that the machine will be stopped in the middle of the process. Furthermore, the outer valve bodies 41A, 4 in the seating position
The force in the valve closing direction that 1B receives from the high pressure gas in the supply/discharge chambers 32A and 32B is greater than the force in the valve opening direction that the inner valve bodies 39A and 39B in the seated positions receive from the high pressure gas in the high pressure chamber 31. The pressure-receiving areas of the valve bodies 39A, 39B, 41A, and 41B are set so that the pressure is also large. Specifically, the outer valve body 41A,
The pressure receiving area πD/4 on the side facing each of the supply/discharge chambers 32A, 32B of the inner valve bodies 39A, 3
Pressure receiving area of the side where 9B faces the pressure chamber 31 πd/
It is set larger than 4. Then, the air supply line 26 is connected to the pressure port 46 communicating with the pressure chamber 31, and both the low pressure chambers 34A,
The exhaust system 27 is connected to a low pressure port 47 that communicates with 34B. Further, one supply/discharge port 48A that communicates with the supply/discharge chamber 32A is connected to the inflow/outflow port 2 via a pipe 49, and the other supply/discharge port 48 that communicates with the supply/discharge chamber 32B.
B is connected to the inflow/outflow port 3 via a conduit 51.

Next, the operation of this embodiment will be explained.

First, the operation of the timing valve 25 will be explained. When the electromagnet 44A of one electromagnetic actuator 42A is temporarily energized, one iron piece 4
5A is attracted by the electromagnet 45A, and the valve stem 36 moves to the first switching position A shown in FIGS. 1 and 3a. As a result, the outer valve body 41A of one supply/discharge chamber 32A is seated on the corresponding outer valve seat 38A, and the inner valve body 39B of the other supply/discharge chamber 32B is seated on the corresponding inner valve seat 37B. As a result, the high pressure gas introduced into the pressure chamber 31 from the air supply system path 26 is guided to the one supply and discharge chamber 32A, and this supply and discharge chamber 3
2A through the supply/discharge port 48A, and is led to one of the expansion chambers 13 as described later. Further, since the other supply/discharge chamber 32B is opened to the low pressure chamber 34B, the low pressure gas discharged from the other expansion chamber 21 passes through the other supply/discharge chamber 32B to the low pressure chamber 34B.
is guided to the exhaust system line 2 through the exhaust port 47.
7. When the electromagnet 44B of the electromagnetic actuator 42B is temporarily energized from this state, the other iron piece 45B is attracted to the electromagnet 44B, and the valve shaft 36 is moved to the second switching position B shown in FIG. 3b.
Move to. As a result, the outer valve body 41B of the other supply/discharge chamber 32B is seated on the corresponding outer valve seat 38B, and the inner valve body 39A of one supply/discharge chamber 32A is seated on the corresponding inner valve seat 37A. As a result, the high-pressure gas introduced into the pressure chamber 31 from the air supply line 26 is guided to the other supply/discharge chamber 32B, and from this supply/discharge chamber 32B to the other expansion chamber 21 through the supply/discharge port 48B. . In addition, the one supply/discharge chamber 3
2A is opened to the low pressure chamber 34A, the low pressure gas discharged from one expansion chamber 13 is guided to the low pressure chamber 34A through the one supply/discharge chamber 32A,
It is discharged to the exhaust line 27 through the low pressure port 47. When the electromagnetic actuator 42A is driven to switch to the first switching position A, the outer valve body 41A is urged in the valve closing direction by the high pressure gas in the supply/discharge chamber 32A. The force is greater than the inner valve body 39B due to the high pressure gas in the pressure chamber 31.
Since this becomes larger than the force biased in the opening direction, each of the valve bodies 41A, 39B is maintained at the switching position A even if the power to the electromagnetic actuator 42A is thereafter cut off. Further, when the electromagnetic actuator 42B is driven to switch to the second position B, the outer valve body 41B is urged in the valve closing direction by the high pressure gas in the supply/discharge chamber 32B. is larger than the force with which the inner valve body 39A is urged in the valve opening direction by the high pressure gas in the pressure chamber 31, so that the electromagnetic actuator 42
Even if the power supply to B is cut off, each of the valve bodies 41B, 39
A is held in its switching position B. Therefore,
In order to switch the timing valve 25, it is sufficient to temporarily energize the electromagnetic actuators 42A and 42B.

Next, the operation of the entire refrigeration system will be explained. First, the first expansion chamber 13 is the smallest, and the second expansion chamber 2
1 is at the maximum (see Figures 1 and 2a), the timing valve 25 is set to position A to connect one of the inflow and outflow ports 2 to the air supply line 26, and the other outflow and inflow port 3 to exhaust air. Connect to line 27.
As a result, high-pressure gas flows from the compressor 28 to the one inlet/outlet port 2 through the air supply line 26. The high pressure gas that has flowed into the inflow/outflow port 2 is guided to the high temperature end 8a of the first regenerator 8 via the communication pipe 4 and the port 7a, and is introduced into the first expansion chamber 13 through the regenerator 8. . Further, a part of the high pressure gas introduced through the communication pipe 4 and the port 7a is also guided to the chamber 10 through the port 7b. In this state, the movable shell 12 is pushed upward by the high pressure gas in the first expansion chamber 13, while the movable shell 12 is pushed downward by the pressure of the high pressure gas in the chamber 10. is urged to. However, the pressure receiving area of the movable shell 12 for receiving the axial pressure component for the expansion chamber 13 corresponds to the cross-sectional area of the communication pipe 4 rather than the pressure receiving area for receiving the axial pressure component for the chamber 10. The movable shell 12 is urged upward and moves by the difference (see imaginary line in FIG. 3a). Note that once the movement begins, the gas passes through the regenerator 8 and continuously enters the expansion chamber 13;
Because pressure loss occurs, the shell upper surface 12a
The pressure pushing up the shell lower surface 12b is slightly smaller than the pressure pushing down the shell lower surface 12b, and the force is almost balanced in relation to the area difference. At this time, since the movable shell 12 moves at a constant velocity, it does not move faster than necessary, and vibrations and the like can be prevented. In other words,
The movable shell 12 operates smoothly and quietly at a slow speed. In this way, when the volume of the first expansion chamber 13 reaches its maximum and is filled with high-pressure gas, the timing valve 25 is switched to position B, and the one inflow/outflow port 2 is connected to the exhaust system. In addition to connecting to 27,
The other inflow/outflow port 3 is communicated with the air supply line 26 (see FIG. 3b). As a result, a part of the gas in the first expansion chamber 13 is blown out through the regenerator 8 and the communication pipe 4 into the exhaust system path 27 and returned to the intake port 28b of the compressor 28. At this time, the gas remaining in the first expansion chamber 13 does the work of pushing out other gases and cools itself. At this stage, as mentioned above, the timing valve 25
is held at position B, the high-pressure gas discharged from the compressor 28 flows through the air supply line 26.
It flows into the other inflow/outflow port 3 through the inflow/outflow port 3.
The high pressure gas that has flowed into the inflow/outflow port 3 is transferred to the chamber 20b, the port 12e and the chamber 20a.
It is guided to the high temperature end 19a of the second regenerator 19 through the regenerator 19, and then introduced into the second expansion chamber 21 through the regenerator 19. In this state, the second expansion chamber 2
The movable shell 12 is pressed downward by the high pressure gas in the chamber 20b, while the movable shell 12 is urged upward by the pressure of the high pressure gas in the chamber 20b. However, the pressure receiving area of the movable shell 12 for receiving the axial pressure component with respect to the expansion chamber 21 is
The area corresponding to the cross-sectional area of the communication pipe 4 is larger than the pressure-receiving area for receiving the axial pressure component (the pressure-receiving area of the portion corresponding to the flange portion is canceled by the upper and lower parts, see Fig. 4b). , the movable shell is urged downward and moved by the difference between them (see the imaginary line in FIG. 3B). At this time, the low-temperature gas remaining in the first expansion chamber 13 passes through the first regenerator 8 while being cooled and is pushed out to the exhaust system path 27. In this way, when the volume of the second expansion chamber 21 reaches its maximum and is filled with high-pressure gas, the timing valve 25 is moved back to position A.
, the other inflow/outflow port 3 is connected to the exhaust system path 27, and one outflow/inflow port 2 is communicated with the air supply system path 26 (see FIG. 3a).
As a result, a portion of the gas in the second expansion chamber 21 is blown out through the second regenerator 19 into the exhaust system passage 27 and returned to the intake port 28b of the compressor 28. At this time, the gas remaining in the second expansion chamber 21 cools itself by pushing out other gases. At this stage, the compressor 28
The high-pressure gas discharged from the is again supplied to one of the inflow and outflow ports 2, and is precooled while being transferred to the first regenerator 8.
is introduced into the first expansion chamber 13, and again,
The movable shell 12 moves upward. and,
At this time, the low-temperature gas remaining in the second expansion chamber 21 passes through the second regenerator 19 while being cooled and is pushed out to the exhaust system path 27. Eventually, by repeating the above operations, the Gifford-McMahon Cycle is completed.
As a result, the upper end portion of the casing 18 becomes extremely cold.

It should be noted that the structure of the main body of the refrigeration system is, of course, not limited to that of the above-mentioned embodiments. A pair is formed by a rotor, a casing surrounding the outer circumferential surface of the rotor, a rotary vane projecting from the outer circumference of the rotor so as to be able to rotate integrally, and a fixed vane protruding from the inner circumference of the casing. It may be of a swinging piston type in which an expansion chamber is formed and the volume of each expansion chamber is alternately increased or decreased by the reciprocating rotation of the rotor.
Alternatively, two conventional reciprocating expanders may be operated with a phase shift of 180°.

Further, the shape of each valve body is not limited to that of the embodiment described above, and may be, for example, a plate-like shape or a slide-and-sleeve type shape as shown in FIG. 5. In FIG. 5, parts that are the same as or correspond to those shown in FIG. 1 are given the same symbols. In this case, the outer valve body is made to have a larger diameter than the inner valve body. Note that even when using a truncated conical valve body as in the above embodiment,
Of course, the outer valve body may have a larger diameter than the inner valve body.

[Effects of the invention] Since the present invention has the above-described configuration, the following effects can be obtained.

First, since there are fewer sliding parts than rotary valves and slide valves, energy loss due to friction and performance degradation due to wear can be effectively suppressed.

Further, since each valve body is opened and closed by an electromagnetic actuator, the structure of the driving part does not become complicated or large.

Furthermore, since each valve element can be held at the switching position by utilizing the pressure of the gas acting on each valve element, it is only necessary to drive the electromagnetic actuator at the moment of switching. Therefore, it is possible to suppress the heat generation in the electromagnetic actuator portion to a minimum source, which can have a positive effect on the refrigeration performance.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is an explanatory diagram schematically showing the whole, FIG. 2 is a longitudinal sectional view showing the main body of the refrigeration system, and FIGS. 3 a and b are explanatory diagrams of operation. , FIGS. 4a and 4b are action explanatory diagrams for explaining the pressure distribution on the movable shell, and FIG. 5 is a schematic sectional view showing another embodiment of the present invention. 13...First expansion chamber, 21...Second expansion chamber, 25...Timing valve, 26...Air supply system path, 27...Exhaust system path, 31...Pressure chamber, 32A
...One supply and discharge room, 32B...The other supply and discharge room, 3
3A...one inner partition wall, 33B...other inner partition wall, 34A...one low pressure chamber, 34B...other low pressure chamber, 35A...one outer partition wall, 35B...other outer partition wall, 36... ... Valve stem, 37A... One inner valve seat, 37B... Other inner valve seat, 38A... One outer valve seat, 38B... Other outer valve seat, 39A...
One inner valve body, 39B...The other inner valve body, 41A
...One outer valve body, 41B...The other outer valve body, 4
2A, 42B...Electromagnetic actuator.

Claims (1)

[Scope of utility model registration request] A timing valve used in a refrigeration system that has a pair of expansion chambers that alternately expand and contract, including a high-pressure chamber that communicates with an air supply line for supplying high-pressure gas, and an inner chamber on both sides of this high-pressure chamber. A pair of supply/exhaust chambers are provided adjacent to each other via a partition wall and communicate with each of the expansion chambers, and an exhaust system line is provided adjacent to the supply/exhaust chambers on the side opposite to the high pressure chamber via an outer partition wall for discharging gas. a low-pressure chamber communicating with the valve shaft, a valve shaft penetrating each of the inner partition walls and each of the outer partition walls so as to be movable in the axial direction;
An inner valve seat provided in each of the valve shaft penetration portions of each of the inner partition walls, an outer valve seat provided in each of the valve shaft penetration portions of each of the outer partition walls, and an outer valve seat supported by the valve shaft and disposed within each of the supply/discharge chambers. a pair of inner valve bodies which are provided and selectively seated on corresponding inner valve seats as the valve stem moves forward and backward; A pair of outer valve bodies are selectively seated on the corresponding outer valve seats as the shaft advances and retreats, and the outer valve body of one supply/discharge chamber corresponds to the inner valve body of the other supply/discharge chamber, respectively. The first seat is seated on the outer valve seat and the inner valve seat.
The valve shaft is moved from the switching position to the second switching position where the outer valve body of the other supply/discharge chamber and the inner valve body of one supply/discharge chamber are seated on the corresponding outer valve seat and inner valve seat, respectively. It is equipped with an electromagnetic actuator that moves forward and backward in an ON/OFF manner. A timing valve for a refrigeration system, characterized in that a pressure receiving area of each valve element is set to be larger than a force in a valve opening direction received from high pressure gas in a high pressure chamber.