JPH042373Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a valve drive device for a reciprocating type cryogenic expander used in He gas liquefaction systems and the like.

[Prior art] For example, He gas is sequentially cooled by a combination of adiabatic expansion of an expander used in a He gas liquefaction system and heat exchange by a heat exchanger, and finally free expansion is performed by a Juul-Thompson valve. When using a reciprocating type cryogenic expander for the Claude cycle, in which liquid He is obtained by This is a technical issue. For this reason, one important issue is how to configure the drive device for the suction and exhaust valves, which are the movable parts of the expander. In other words, it goes without saying that arranging a drive source that generates heat, such as a solenoid, near the low temperature side of the expander is not preferable in terms of preventing heat intrusion.
It is also inappropriate to employ a mechanism that causes friction in the valve drive system. On the other hand, from the perspective of removing the cause of heat generation from the low-temperature side of the expander, the drive sources for the intake and exhaust valves are placed outside the room-temperature side of the expander, and they are mechanically driven in synchronization with the expander cycle. Although it is advantageous to do so, on the other hand, in this case, the mechanism of the drive device inevitably becomes complicated. In other words, if you do this, the suction from the drive source on the room temperature side to the low temperature side,
The valve driving member for transmitting the operation to the exhaust valve must be installed at least from each valve chamber housing the valve to the insulating vacuum chamber installed surrounding the expander main body, and the working gas There is a need for a sealing structure that reliably prevents gas leakage between each valve chamber filled with gas and the inside of the adiabatic vacuum chamber.

[Problems to be solved by the invention] The present invention has been made focusing on the above-mentioned circumstances, and based on the latter idea, it is a valve drive device for a reciprocating type cryogenic expander. There are no heat sources or unnecessary friction parts on the side, which effectively prevents heat intrusion from the outside, and also eliminates sealing problems caused by the valve driving member penetrating the surrounding insulating vacuum chamber from the valve chamber. The aim is to provide a simple and rational structure that can be easily and reliably solved.

[Means for Solving the Problems] The present invention achieves this purpose by providing an intake valve and an exhaust valve provided at the intake port and exhaust port of the expansion chamber on the low temperature side of the main body of the reciprocating expander. The valve drive device is configured to open and close a valve by swinging a lever rod that is installed through a valve chamber housing these suction and exhaust valves and an insulated vacuum chamber surrounding the expander main body, the valve driving device including The intake valve and the exhaust valve are each fixedly installed at an end on the valve chamber side, and a reciprocating rod is pivotally connected to the end on the vacuum chamber side for swinging the ram about a fulcrum at a midway point in the longitudinal direction. Further, a diaphragm that airtightly partitions the valve chamber and the adiabatic vacuum chamber is provided around the part of the ram that penetrates the partition wall separating the valve chamber and the adiabatic vacuum chamber, and the fulcrum of the ram is aligned with the plane on which the diaphragm is stretched. Provided is a valve drive device for an expander, characterized in that the valve drive device is positioned in the vicinity of the expander.

[Function] With this configuration, a drive source for reciprocating the reciprocating rods, which are pivotally connected to one end of the rod using a cam mechanism or the like, is provided on the room temperature side in synchronization with the cycle of the expander. , the lever swings around its fulcrum in conjunction with the reciprocating motion of these reciprocating rods, and the intake valve and exhaust valve, which are fixed at the end of each valve chamber, alternately approach and separate from their valve seats. , the intake port and the exhaust port can be reliably opened and closed at predetermined timings. At this time, gas leakage from the valve chamber into the adiabatic vacuum chamber through which the ram extends is effectively sealed by a diaphragm stretched around the ram at the part that penetrates the partition wall separating both chambers. Moreover, since the fulcrum of the ram is located near the plane on which the diaphragm is stretched, even if the ram is repeatedly oscillated, there is almost no displacement at the position of the diaphragm, thus keeping the diaphragm in an almost stationary state. It is possible to keep it.

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

FIG. 1 shows the main parts of a reciprocating type cryogenic expander according to the present invention. This type of expander is, for example, a Claude cycle as shown in Figure 6.
This is used for He liquefaction equipment. That is,
Specifically, this liquefaction device includes a compressor a,
An air supply system line b for guiding the high-pressure helium gas pumped from the compressor a and finally allowing it to freely expand at the Juul-Thompson valve c to blow out gas containing liquid helium mist into the dewar d; , an exhaust system path e for returning the helium gas vaporized in the dewar d to the intake side of the compressor a, and for circulating the helium gas; Heat exchangers f ₁ to _{f 5} of an appropriate number of stages are used to transfer and pre-cool the flowing gas through the air supply system path b, and a portion of the high pressure gas passing through the air supply system path b is introduced and cooled. It is equipped with an appropriate number of stages of expanders g ₁ and g ₂ that cool the air by adiabatic expansion and then return it to the exhaust system path e, and the expander shown in FIG. 1 is used for these g ₁ and g ₂ . It illustrates what will be done. Note that in order to obtain a large refrigerating capacity, this type of cryogenic refrigerator typically uses a turbine-type expander in systems with a large He flow rate, but it is advantageous in terms of efficiency in the case of a small flow rate. A reciprocating type is preferably used.

The structure of this expander, together with its valve driving device, will be explained with reference to FIG. 2a, an expandable and contractible expansion chamber 4 is formed. A hollow heat insulating vacuum chamber 5 is surrounded around the cylinder 2 of the expander main body 1 to block heat from entering from the outside. The expansion chamber 4 is provided with an intake port 6 and an exhaust port 7 that open into the expansion chamber 4 from the cylinder bottom plate 2a, and the intake port 6 is provided at the bottom of the expansion chamber 4 sandwiching the cylinder bottom plate 2a. Valve chambers 10 and 11 are separated from each other and each house an intake valve 8 and an exhaust valve 9, which open and close the exhaust port 7 alternately. The intake valve 8 and exhaust valve 9 housed in the valve chambers 10 and 11, respectively, are mushroom-shaped in the illustrated example, and are mounted on valve seats 8a and 9a formed on the bottom side of the intake port 6 and exhaust port 7, respectively. The ports 6 and 7 are arranged to face each other and are opened and closed by moving up and down toward and away from the valve seats 8a and 9a. And this intake valve 8
The exhaust valve 9 and the exhaust valve 9 are fixedly installed at one end of the lever rods 12 and 13 that penetrate from the respective valve chambers 10 and 11 into the surrounding adiabatic vacuum chamber 5, and the swinging motion of each of the lever rods 12 and 13 is utilized. and intake port 6 and exhaust port 7
I'm trying to open and close it.

The supporting and swinging mechanism of the levers 12 and 13 will be explained in detail (only the mechanism on the intake valve 8 side is shown in the figure since they have a common mechanism).
The lever 12 is connected to an outer wall 14 forming the valve chamber 10.
It penetrates through the vacuum insulation chamber 5 on the outer periphery through the through hole 15 provided on one side, and as mentioned above, the intake valve 8 is fixedly installed on the upper surface side of the valve chamber side end. A reciprocating rod 17 is pivotally connected to the opposite end of the vacuum chamber through a joint 16. This reciprocating rod 17 extends from above into the insulating vacuum chamber 5 from the room temperature side to the low temperature side of the expander body 1, and its end on the room temperature side is not shown in the figure. The rod 17 is connected to a driving source that reciprocates the rod 17 using a driving means for reciprocating the piston 3 and a cam mechanism. and,
This reciprocating rod 17 performs its up-and-down movement using the rod 1.
2, it is converted into a swinging motion that causes the lever 12 to swing around a fulcrum S located midway in the longitudinal direction, and is transmitted.
That is, when the reciprocating rod 17 descends, the intake valve 8 at the other end moves up to close the intake port 6, and when the reciprocating rod 17 moves up, the intake valve 8 at the other end moves down to open the intake port 6.

Further, at a portion where the lever 12 penetrates the partition wall separating the valve chamber 10 and the adiabatic vacuum chamber 5, that is, at a through hole 15 in the outer wall 14, the through hole 15 is provided in order to maintain airtightness of both chambers. A diaphragm 18 is stretched around the ram 12 so as to block it. In the illustrated example, the diaphragm 18 is a hollow thin film body having an annular flexible portion 18C that is folded back once at its radius center, and its outer peripheral edge 18a is placed inside the valve chamber outer wall 14. On the other hand, the inner circumferential edge portion 18b thereof is sandwiched between the lever 12 and stretched around the lever 12 in an airtight manner. In order to hold the diaphragm inner peripheral edge 18b, the lever 12 is separated into two rod parts 12a and 12b on the valve chamber side and the vacuum chamber side, and the spigot joint part 1 of both parts is separated into two rod parts 12a and 12b.
2c has a connection structure in which the diaphragm inner circumferential edge 18b is sandwiched between the diaphragm inner peripheral edge 18b and the diaphragm 2c is integrally attached. Also,
This lever 12 has a pair of side arms 19 extending integrally from both sides of the lever portion 12a on the vacuum chamber side.
19 and support shafts 20, 20, the shafts 20, 20 are pivoted freely to the side wall of the valve chamber outer wall 14, and the axes s of the support shafts 20, 20, which serve as the rocking fulcrum.
is made to coincide with the plane in which the diaphragm 18 is stretched over the opening 15.

The movable members such as the ram 12 and the reciprocating rod 17 are preferably made of stainless steel or the like having low thermal conductivity. 21 in the figure is connected to the expansion chamber 4 through the valve chamber 10 and the intake port 6.
An intake pipe for introducing He gas (working gas) is shown (an exhaust pipe is connected to the valve chamber 11 on the side not shown).

The operation and effects of the valve drive device having the above configuration will be explained.

When the reciprocating rod 17 penetrating the insulating vacuum chamber 5 is reciprocated in synchronization with the cycle of the expander main body 1 using a drive source located on the room temperature side, the ram 12 moves to its fulcrum s. Accordingly, the intake valve 8 fixed to one end of the intake valve 8 moves up and down to come into contact with and leave the valve seat 8a, thereby opening and closing the intake port 6. The exhaust valve 9 on the exhaust port 7 side is also opened and closed by a similar mechanism (not shown).
By alternately opening and closing these suction and exhaust valves 8 and 9 at predetermined timing, it is possible to cause the expander main body 1 to carry out the necessary adiabatic expansion cycle. If it is like this, the valve driving source is connected to the expansion chamber 4.
It does not need to be installed on the nearby low temperature side, and as will be described later, its movable parts have almost no friction-causing parts, so the cause of heat intrusion that reduces the efficiency of the expander is effectively eliminated, and its absorption and The difficulty associated with the fact that the lever 12, which is the operating member of the exhaust valves 8, 9, penetrates from the valve chambers 10, 11 into the heat insulating vacuum chamber 5 can also be accurately solved.

That is, the lever 12, which is swung around its fulcrum s by the vertical movement of the reciprocating rod 17 at one end, aligns the fulcrum s with the tension plane of the diaphragm 18 that airtightly partitions the valve chamber 10 and the insulating vacuum chamber 5. Since it is pivotally supported on the outer wall 14 of the valve chamber, the diaphragm 1 does not move even when the lever 12 swings, as shown in FIG.
There is almost no displacement in the vicinity of the joint portion 12c that sandwiches the diaphragm 18, and therefore the diaphragm 18 can be kept almost stationary. For this reason,
The inconvenience of friction between the diaphragm 18 and the lever 12 is reliably avoided, and the diaphragm 1
Since no unreasonable force or deformation is caused to the diaphragm 8 itself, durability and permanent sealing performance of the diaphragm 18 are guaranteed. In other words, by aligning the position of the fulcrum s with its tension plane, the diaphragm 18 prevents gas leakage from the valve chamber 10 filled with helium gas to the insulating vacuum chamber 5.
Thus, a sealing structure that reliably prevents this is realized. Even if there is a large pressure difference between the outer adiabatic vacuum chamber 5 and the inner valve chamber 10 in the lever 12, no resistance to rotation can be generated around the fulcrum s, and as mentioned above, the diaphragm 1
Since the contact resistance with 8 can be ignored, the reciprocating rod 1
7, it is possible to operate smoothly with a light driving force.

Although one embodiment has been described above, the present invention is of course not limited to the illustrated embodiment. For example, in the above embodiment, the side arms 19, 19 and support shafts 20, 20 integrally connected to each other extend from the ram 12 as a support structure for the ram 12, but this is shown in FIG. like,
Disassembly and assembly type side arm 19, support shaft 20, 2
0, bolts 22, etc., to simplify the support structure. The support means for the ram 12 may be of any specific type, as long as its swinging fulcrum is positioned on a predetermined plane, but the simplest method is to directly support it with the diaphragm 18. can.

Regarding the type of intake and exhaust valves 8 and 9, in the above embodiment, a mushroom-shaped valve is integrally fixed to the end of the valve chamber of the lever 12, and this is connected to the intake and exhaust ports 6 and 7 facing each other. Although the example has been shown in which the valve seats 8a and 9a are fitted into and separated from each other, this may be changed to a valve mechanism of the type shown in FIG. 4 or the like. That is, in this modified example, the intake and exhaust ports 6 and 7 face the tiltable valves 8 and 9 having flat valve surfaces.
The flat valve seats 8a and 9a are brought into contact with and separated from each other by the swinging movement of a lever 12.

Furthermore, the type of diaphragm 18, the tensioning means, etc. can be modified in various other ways. For example, in the above embodiment, a shape having a flexible portion 18c in the middle in the radial direction is used, but this may be simply a thin plate shape. Furthermore, the number of diaphragms 18 provided in the through hole 15 is not necessarily limited to one, and may be provided in multiple stages if necessary. FIG. 5 shows an example of such a device, in which two diaphragms 18, 18 are installed on both sides of the valve chamber 10, 11 side and the insulating vacuum chamber 5 side of the through hole 15 provided in the valve chamber outer wall 14.
It is set up in tiers. In addition, when the diaphragms 18 are provided in multiple stages, the swinging fulcrum s of the ram 12 is positioned near each of the tension planes, so that the displacement of each diaphragm 18 is minimized. In addition, a bellows or the like can be used instead of a diaphragm, and in short, any elastic disk-like body is sufficient.

Note that the cross-sectional shapes of the lever 12, the reciprocating rod 17, and other members are of course arbitrary, and may have a rectangular cross-section, for example.

[Effects of the invention] As described above, according to the invention, there is no need to provide a drive source for driving the intake and exhaust valves on the low temperature side, and a mechanism with almost no friction in the moving parts can be realized. Therefore, the cause of heat intrusion into the cryogenic expander can be effectively eliminated, and at the same time,
The structural difficulties associated with the fact that the ram that directly operates the exhaust valve is installed from the valve chamber into the surrounding insulated vacuum chamber can be rationally solved by using a diaphragm positioned and stretched near the fulcrum of the ram. Therefore, it is possible to provide a valve driving device that can reliably prevent gas leakage into an insulated vacuum chamber.

[Brief explanation of the drawing]

FIG. 1 is a cutaway perspective view of essential parts of a cryogenic expander showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing its operation. FIG. 3 is a perspective view showing a partially modified example, and FIGS. 4 and 5 are side views of the same. FIG. 6 is a schematic diagram of a refrigeration cycle showing an example of use of the expander according to the present invention. 1... Expander main body, 4... Expansion chamber, 5... Insulated vacuum chamber, 6... Intake port, 7... Exhaust port,
8... Intake valve, 9... Exhaust valve, 10, 11... Valve chamber, 12, 13... Ram rod, 14... Valve chamber outer wall (partition), 15... Penetration port, 17... Reciprocating rod, 18 ...Diaphragm, 19...Side arm, 20...Spindle, s...Swinging fulcrum.

Claims (1)

[Scope of utility model registration request] An adiabatic vacuum surrounds the expander body from the valve chamber housing the intake and exhaust valves, which are connected to the intake and exhaust valves provided at the intake and exhaust ports of the expansion chamber on the low-temperature side of the reciprocating expander body. A valve drive device which is opened and closed by the swinging of a lever rod extending through a chamber, wherein the intake valve and the exhaust valve are each fixed to an end of the lever on the valve chamber side,
A reciprocating rod for swinging the ram about a fulcrum at a midway point in the longitudinal direction is pivotally connected to the vacuum chamber side end, and a ram ram at a portion that penetrates a partition wall separating the valve chamber and the insulating vacuum chamber An elastic disk-like body is placed around the chamber to airtightly partition these two chambers, and
A valve drive device for an expander, characterized in that the fulcrum of the ram is positioned near a plane on which the elastic disk-like body is stretched.