JPH0566510B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cryogenic refrigeration device applicable to cryopumps, He liquefaction devices, and the like.

[Prior Art] Conventionally, this type of refrigeration equipment has a piston-shaped displacer slidably fitted in a cylinder, and the displacer is reciprocated to reduce the low temperature between the displacer and the cylinder. The volume of the expansion chamber formed between the end and the end can be increased or decreased, and by expanding or contracting the expansion chamber, the gas can be expanded in sequence to run a predetermined refrigeration cycle.

By the way, there are conventional types in which the regenerator is held inside the displacer and types in which it is disposed outside the cylinder, but both have the following problems. . That is, a displacer in which a regenerator is provided has a disadvantage in that the inertial mass of the movable part is large and vibrations are likely to occur. Further, in the case where the regenerator is provided outside the cylinder (including the outer circumferential surface of the cylinder wall), there is a problem that there is a wasted volume inside the displacer, and the bulk of the entire device increases. Furthermore, various mechanisms have been devised to control the movement of this displacer, but each of them increases the number of gas seals and adds complicated moving parts, making the device complicated. was.

In order to eliminate such inconveniences, the cryogenic refrigeration equipment is equipped with an internal regenerator supported by a fixed member,
a movable shell that is slidably fitted around the outer periphery of the regenerator and forms an internal expansion chamber between the low temperature end of the regenerator and the low temperature end of the regenerator; an external regenerator; a casing that is provided to surround the external regenerator and forms an external expansion chamber between the low temperature end of the external regenerator and the movable shell; It has been considered to include a timing valve that connects to the air supply system path or the exhaust system path at a preset timing. If it's something like this,
Since the pressure of the cooling gas can be used to slide the working shell, there is no need for a drive unit and the structure is simple.In addition, the working shell can undergo two adiabatic expansions per reciprocation, so it can be made larger for the same size. It has the advantage of providing refrigeration capacity.

However, such a method also has the following disadvantages. That is, even if the movable shell is accelerated by the gas, there is no means to decelerate the movable shell, so the movable shell does not stop until it collides with the stopper at the slide end position.
Vibrations are generated by the collision.

[Problems to be Solved by the Invention] The present invention has been made focusing on the above-mentioned circumstances, and provides a cryogenic refrigeration device that has a simple structure, has a high refrigerating capacity, and does not generate vibrations due to the collision. The purpose is to

[Means for Solving the Problems] In order to achieve the above object, the present invention is provided on the external high temperature end side of the movable shell in the considered cryogenic refrigeration apparatus, and is provided at the external high temperature end side of the movable shell to move the movable shell to the slide end position. It is characterized by the provision of a gas damper that decelerates the slide from the vicinity and stops it at the slide end position.

[Function] According to such a configuration, as the movable shell reciprocates, the internal expansion chamber formed inside the movable shell and the external expansion chamber formed outside the movable shell alternately expand and contract. I will do it. Therefore, high-pressure gas introduced into the internal expansion chamber from the supply air system path through the internal regenerator expands in this expansion chamber, becomes low temperature, and is discharged to the exhaust system path again through the internal regenerator and circulated. , High-pressure gas introduced from the air supply system path through the external regenerator into the external expansion chamber expands in the expansion chamber to become low temperature, and is again discharged through the external regenerator to the exhaust system path and circulated. It turns out. Furthermore, since the gas damper decelerates the movable shell from near the slide end position of the movable shell, the movable shell stops at the slide end position without any impact.

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

FIG. 1 is a longitudinal cross-sectional view of a small-sized cryogenic refrigeration apparatus according to the present invention, and numeral 1 in the figure is a base serving as a fixing member. The base 1 has a disc-shaped upper end, and has a pair of inlet and outlet ports 2 and 3 in the 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-stage internal regenerator 8 is placed on this mounting disk 7 and fixed with a plurality of bolts 9a. This internal regenerator 8 is constructed by stacking heat storage elements 11 and spacers (not shown) in multiple stages alternately. 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 this internal 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 via the port 7b formed in the mounting disc 7.
It communicates with the chamber 10 via. Further, the low temperature end 8b of the internal regenerator 8 is communicated with the high temperature end 13a of the second stage internal regenerator 13 through a port 12a, a communication path 12b, and a port 12c formed in the mounting member 12. . This mounting member 12 is
Disc-shaped mounting members 12s are provided at both the upper and lower ends, respectively.
12e. The internal regenerator 13 is also made up of a plurality of stacked heat storage elements 11 and spacers (not shown) alternately stacked together, and a plurality of bolts 9
It is fixed by b. A movable shell 14 is slidably fitted around the outer periphery of these internal regenerators 8 and 13. The movable shell 14 is a two-stage cylindrical body that fits around the outer periphery of the regenerators 8 and 13, and its first stage portion 14a surrounds the internal regenerator 8 of the first stage,
The second-stage internal regenerator 13 is surrounded by the second-stage portion 14b. A first-stage internal expansion chamber 16 is formed between the first-stage ceiling wall 14c of the movable shell 14 and the low-temperature end 8b of the first-stage internal regenerator 8, and the first-stage internal expansion chamber 16 is Member 12
port 12a, communication path 12b and communication hole 12
It communicates via f. Further, the end of the second stage portion 14b on the low temperature side is closed by the second stage ceiling wall 14d. In addition, the second stage ceiling wall 14
d and the low temperature end 13b of the internal regenerator 13, a second stage internal expansion chamber 17 is formed. Also,
A shaft hole 14f is bored in the center of the bottom wall 14e at the end of the first stage of the movable shell 14 on the high temperature side. They are slidably fitted. Further, a first stage external regenerator 21 and a second stage external regenerator 22 are provided around the outer periphery of the movable shell 14, which are held in a casing 19. The casing 19 is a two-stage cylindrical body that encloses the external regenerators 21 and 22, and has a top wall 19a at the end on the low temperature side of the first stage, and a top wall 19a at the end on the low temperature side of the second stage. The end portion is closed by an inverted cup-shaped top wall 19b. Also, this casing 19
A flange portion 19e is provided on the high temperature end side of the base 1, and the flange portion 19e is attached to the upper opening of the base 1 via a sealing member 20.
Then, the high temperature end 22a of the second stage external regenerator 22
A first stage external expansion chamber 23 is located between the top wall 14c of the movable shell 14 and the top wall 14c of the casing 19.
A second stage external expansion chamber 24 is formed between the movable shell 9b and the top wall 14d of the movable shell 14, respectively. Both of the external regenerators 21 and 22 are constructed by stacking a plurality of heat storage elements 25 and spacers (not shown) alternately, and bolts 26a and 26b, respectively.
It is fixed to the casing 19 using.
The heat storage element 25 is an annular element made of copper or the like, and has a large number of ventilation holes 25a penetrating vertically.
have. The spacer is made of stainless steel wire or the like. Note that the high temperature end 21a of the first-stage external regenerator 21 communicates with the inflow/outflow port 3 via the chamber 28. Moreover, the low temperature end 21b of this regenerator 21 is connected to the casing 1
It communicates with the high temperature end 22a of the second-stage external regenerator 22 via the port 19c provided at 9 and the external expansion chamber 23. The low temperature end 22b of the second stage external regenerator 22 communicates with the external expansion chamber 24 via the port 19d.

Both the inflow and outflow ports 2 and 3 are connected to an air supply system path 32 or an exhaust system path 33 via a timing valve 31. Specifically, the timing valve 31 is composed of a slide valve or the like in which a port is operated by a motor to switch ports.
It is designed to switch in the manner shown by symbols in FIG. That is, at position A, one outflow/inflow port 2 is connected to the air supply system path 32, and the other outflow/inflow port 3 is connected to the exhaust system path 33. In addition, at position B, one of the inflow and outflow ports 2 is connected to the exhaust system path 33, and
The other inflow/outflow port 3 is connected to an air supply line 32. The position A and the position B are alternately switched. The air supply line 32 is for supplying high pressure gas discharged from the discharge port 34a of the compressor 34 to the air supply port 31a of the timing valve 31 through the cooler 35, This is for guiding low pressure gas discharged from the exhaust port 31b of the timing valve 31 to the intake port 34b of the compressor 34.

Further, a gas damper 36 is disposed on the external high temperature end side of the movable shell 14. This gas damper 36 has a movable member 37 formed in an annular shape and an annular fixed member 38 protruding from the inner periphery of the casing 19 . The movable member 37 has a flange 37a on the inner periphery of the upper end, a flange 37b on the outer periphery, a flange 37c on the inner periphery of the lower end, and a flange 37d on the outer periphery, and slides on the inner periphery of the casing 19. Sliding contact possible. The fixed member 38 is
The fluid chamber 39 is disposed between the flanges 37b and 37d on the outer peripheral side of the movable member 37, and the fluid chamber 39 is disposed between the flanges 37b and 37d on the outer peripheral side of the movable member 37.
A fluid chamber 41 is formed between the flange 37d and the flange 37d. These fluid chambers 39 and 41 are filled with gas, and both chambers 39 and 41 are communicated through a narrow fluid passage 42. Moreover, between the inner peripheral side collars 37a and 37c, the movable shell 1
A protrusion 43 is provided that protrudes from the high temperature end of 4. This protrusion 43 slides together with the movable shell 14, and comes into contact with the collar 37a near the end position of the upward slide, thereby causing the movable member 37 of the gas damper 36 to slide upward together. Near the end position of the downward slide, the movable member 37 comes into contact with the collar 37c and slides downward together.

Next, the operation of this embodiment will be explained.

The internal expansion chambers 16 and 17 are the smallest, and the external expansion chamber 2
3 and 24 are at maximum (see FIGS. 1 and 2 a), the timing valve 31 is set to position A to communicate one inflow/outflow port 2 with the air supply system path 32, and the other outflow/inflow port 3 is connected to the exhaust system line 33. As a result, high-pressure gas flows from the compressor 34 through the air supply system 32 to the one inflow/outflow port 2 . The high-pressure gas that has flowed into the inflow/outflow port 2 is guided to the high temperature end 8a of the first-stage internal regenerator 8 via the communication pipe 4 and port 7a, and the gas that has passed through the regenerator 8 is attached to the mounting member 12. Port 12a, communication path 12b and communication hole 12f
It is introduced into the first stage internal expansion chamber 16 through the.
A part of the gas that has passed through the regenerator 8 is introduced into the second-stage internal regenerator 13 via the port 12a, the communication path 12b, and the port 12c of the mounting member 12, and is introduced into the second-stage internal regenerator 13. It passes through the regenerator 13 and is introduced into the second-stage internal expansion chamber 17. Further, a part of the high pressure gas introduced through the communication pipe 4 and the port 7a is transferred to the chamber 1 through the port 7b.
It also leads to 0. In this state, the movable shell 14 is pushed upward by the high pressure gas in the internal expansion chambers 16 and 17, while the movable shell 14 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 14 for receiving the axial pressure component with respect to the expansion chambers 16 and 17 is
Since the pressure receiving area for receiving the axial pressure component on the chamber 10 is larger by an amount corresponding to the cross-sectional area of the communication pipe 4 (see FIG. 3a), the movable shell 14 is moved upward due to the difference. It moves under pressure (see Figure 2b). At the start of this movement, the protrusion 43 is attached to the collar 3 on the lower end side of the movable member 37.
7c (see Fig. 4a). and,
Once movement begins, the gas is stored in internal regenerators 8 and 13.
The regenerators 8 and 13 continuously enter the expansion chambers 16 and 17, but at this time, pressure loss occurs due to the regenerators 8 and 13, so the shell upper surface 14c14
The pressure pushing up d is slightly smaller than the pressure pushing down shell lower surface 14e, and the forces are almost balanced in relation to the area difference. At this time, the movable shell 14 moves at a constant velocity. When the movable shell 14 reaches the vicinity of the upper slide end position, the protrusion 43 moves against the movable member 37 of the gas damper 36.
The movable member 37 comes into contact with the collar 37a at the upper end of the movable shell 14 (see FIG. 4b), and moves up together with the movable shell 14.
Then, as the movable member 37 rises, the volume of the fluid chamber 41 decreases while the volume of the fluid chamber 39 increases. Due to this change in volume, the fluid chamber 41
The gas inside moves to the fluid chamber 39, but both chambers 39,
Since the fluid passage 42 that connects the gases 41 to 41 is narrow, large frictional resistance occurs when the gas passes through the fluid passage 42. This frictional resistance is transmitted to the movable shell 14 via the movable member 37 and the protrusion 43, and brakes the upward movement of the movable shell 14. Then, the movable shell 14 is gradually decelerated by the brake and stopped at a predetermined slide end position. At this time, the movable member 37 has slid upward to a predetermined position (see FIG. 4c). In this way, when the internal expansion chambers 16 and 17 have reached their maximum volume and are filled with high-pressure gas, the timing valve 31 is switched to position B, and the one inflow/outflow port 2 is connected to the exhaust system. 33, and the other inflow/outflow port 3 is communicated with the air supply system path 32 (see FIG. 2c). As a result, a part of the gas in the internal expansion chambers 16 and 17 passes through the regenerator 8 and the communication pipe 4 to the exhaust system path 3.
3 to the air intake port 34 of the compressor 34.
Returned to b. At this time, the internal expansion chamber 16,1
The gas remaining inside 7 cools itself by pushing out other gases. At this stage, since the timing valve 31 is held at position B as described above, the high pressure gas discharged from the compressor 34 flows into the other inflow/outflow port 3 through the air supply line 32. This inflow/outflow port 3
The high pressure gas that has flowed into the chamber 28 is guided to the high temperature end 21a of the first stage external regenerator 21,
Through this regenerator 21, the first stage external expansion chamber 23
will be introduced in Further, a part of the gas introduced into the external expansion chamber 23 passes through the second-stage external regenerator 22 and is introduced into the second-stage external expansion chamber 24 . In this state, the movable shell 14 is pushed downward by the high pressure gas in the external expansion chambers 23 and 24, while the movable shell 14 is pushed upward by the pressure of the high pressure gas in the chamber 28. is urged to. However, the pressure receiving area of the movable shell 14 for receiving the axial pressure component with respect to the external expansion chambers 23 and 24 is larger than the pressure receiving area of the movable shell 14 with respect to the axial direction pressure component of the chamber 28. Since the movable shell is larger by an amount corresponding to the area (see FIG. 3b), the movable shell is urged downward and moved by the difference (see FIG. 2d).
At this time, the low-temperature gas remaining in the internal expansion chamber 13 passes through the internal regenerator 8 while being cooled and is pushed out to the exhaust system path 33. When the movable shell 14 reaches the vicinity of the downward sliding end position, the protrusion 43 abuts against the collar 37c at the lower end of the movable member 37 of the gas damper 36 (see FIG. 4d), and the movable member 37 moves the movable shell 14 and descend together. Then, as the movable member 37 descends, the fluid chamber 3
While the volume of fluid chamber 9 decreases, the volume of fluid chamber 41 increases. Due to this change in volume, the gas in the fluid chamber 39 moves to the fluid chamber 41, but as described above,
When the gas passes through the fluid passage 42, a large frictional resistance is generated. This frictional resistance
7. It is transmitted to the movable shell 14 via the protrusion 43, and applies a brake to the downward movement of the movable shell 14. Then, the movable shell 14 is gradually decelerated by the brake and stopped at a predetermined slide end position. At this time, the movable member 37 returns to the position at the start of operation (see FIG. 4a). In this way, when the volumes of the external expansion chambers 23 and 24 reach their maximum and are filled with high-pressure gas, the timing valve 31 is switched to position A again,
The other inflow/outflow port 3 is connected to the exhaust system path 33, and one outflow/inflow port 2 is communicated with the air supply system path 32 (see FIG. 2a). the result,
A portion of the gas in the external expansion chambers 23 and 24 is blown out through the external regenerators 21 and 22 into the exhaust system path 33 and returned to the intake port 34b of the compressor 34. At this time, the gas remaining in the external expansion chambers 23 and 24 works to push out other gases and cools itself. At this stage, the compressor 3
The high pressure gas discharged from 4 is again supplied to one of the inflow and outflow ports 2, passes through the internal regenerators 8 and 13 while being precooled, is introduced into the internal expansion chambers 16 and 17, and is again introduced into the movable shell. 14 moves upward. At this time, the external expansion chambers 23, 24
The low temperature gas remaining in the external regenerators 21 and 22
The air passes through the air while being cooled and is pushed out to the exhaust system path 33. Therefore, by repeating the above operations, the Gifford McMahon cycle (Gifford
-Mcmahon Cycle) is carried out, and the upper end portion of the casing 19 becomes extremely cold.

In this way, it performs its freezing action,
This is the first stage portion 14a of the movable shell 14.
Expansion chambers 16 and 23 are provided on both upper and lower sides of the ceiling wall 14c, respectively, and the ceiling wall 1 of the second stage portion 14b is
Expansion chambers 17 and 24 are provided on both the upper and lower sides of 4d, and the expansion chambers 16 and 24 are provided through different regenerators 8 and 21, respectively.
Gas is supplied to the expansion chambers 17 and 24 through the regenerators 13 and 22, respectively. Therefore, independent refrigeration cycles are operated using the expansion chambers 16, 17 and regenerators 8, 13, and the expansion chambers 23, 24 and regenerators 21, 22, respectively. Moreover, the expansion chamber 16,
17 and the expansion chambers 23 and 24 alternately expand and contract due to the reciprocating motion of the movable shell 14, so that the expansion operation can be performed twice for each reciprocating motion of the movable shell 14, and the same frequency If so, the refrigeration capacity can be approximately doubled compared to conventional ones. Furthermore, internal expansion chambers 16, 17, external expansion chambers 23, 2
Since both 4 are formed in two stages, casing 1
In the vicinity of the top wall 19b of 9, a lower temperature can be obtained than in the case where there is only one stage. Moreover, since the movable part is a hollow shell, the inertial mass is small and vibration can be significantly reduced. Furthermore, since the regenerator 8 is disposed by effectively utilizing the internal space of the movable shell 14, it is possible to make the regenerator more compact than conventional products in which the regenerator is disposed outside the casing. In addition, when operating the Gifford McMahon cycle as in this embodiment, due to the presence of the communication pipe 4 penetrating the high temperature end side of the movable shell 14, the pressure receiving area on the room temperature end side of the movable shell 14 is reduced to the low temperature end side. Taking advantage of the fact that the movable shell 14 is smaller than the pressure receiving area on the side, it becomes possible to move the movable shell 14 only by the urging force of the high pressure gas. Therefore, no mechanism for operating the deplacer (movable shell) is required, and the structure can be greatly simplified.

In addition, since the slide of the movable shell 14 is decelerated from near the end position of the slide by the gas damper 36 and stopped at the end position, the slide of the movable shell 14 is decelerated from near the end position of the slide, so that the slide of the movable shell 14 is stopped at the end position. The inconvenience that occurs when vibration occurs does not occur.

Note that the present invention is not limited to a refrigeration system operating on the Gifford-McMahon cycle, but can be similarly applied to, for example, a small-sized cryogenic refrigeration system using a Solvay cycle, a Stirling cycle, or the like.

Further, in the above embodiment, a two-stage type was described, but the present invention is of course applicable to a one-stage type and a multi-stage type of three or more stages.

Furthermore, the configuration of the gas damper is not limited to that of the embodiment described above. For example, the movable member may be provided with a piston, and the fixed member may be a lid fixedly provided above and below the piston, respectively. Further, an elastic member may be attached to a contact surface between the protrusion and the inner periphery side collar. Furthermore, the protrusion may be flexible and may have an elastic effect. Further, a seal may be placed in a sliding portion of the movable member with the inner circumferential surface of the casing. Further, the fluid passage is not limited to the gap between the fixed member and the movable member, but may be, for example, a throttle hole provided in the fixed member.

Furthermore, the cold storage material is not limited to a perforated plate, but may also be a pressed nut material.

[Effects of the Invention] Since the present invention has the above-described configuration, it provides a cryogenic refrigeration device that has high refrigerating capacity, has a simple structure, can be made compact, and does not generate vibrations. It is possible.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a longitudinal sectional view, Fig. 2 a, b, c, and d are explanatory diagrams of operation, and Fig. 3 a, b explains pressure distribution on the movable shell. Figures 4a, b, c, and d are explanatory views of the operation of the gas damper. 1... Fixed member (base), 8, 13... Internal regenerator, 14... Movable shell, 16, 17... Internal expansion chamber, 19... Casing, 21, 22...
External regenerator, 23, 24...External expansion chamber, 31...
...Timing valve, 32...Air supply system path, 33...
...Exhaust system path, 36...Gas damper, 37...Movable member, 38...Fixed member, 39, 41...Fluid chamber, 42...Fluid passage, 43...Protrusion.

Claims (1)

[Claims] 1. An internal regenerator supported by a fixed member, and an internal expansion chamber that is slidably fitted around the outer periphery of the regenerator to form an internal expansion chamber between its low temperature side end and the low temperature end of the regenerator. A hollow movable shell, an external regenerator disposed around the outer periphery of the movable shell, and an external regenerator provided to surround the external regenerator between the lower end of the movable shell and the movable shell. A casing forming an external expansion chamber that communicates with the installed regenerator, and a cooling gas that connects the high temperature end of each regenerator to an air supply system path or an exhaust system path at a preset timing and discharges from the air supply system path. a timing valve that presses a pressure receiving surface of the movable shell to slide the movable shell; and a gas damper that is provided on the external high temperature end side of the movable shell and that decelerates the movable shell from near the slide end position and stops the movable shell at the slide end position. A cryogenic freezing device that is characterized by