JPH0996455A - Gas compressing/expanding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas compressing/expanding machine of a favorable thermal efficiency, which prevents a heat loss from generating. SOLUTION: At one part of a gas passage which communicates with a driving chamber through the inside of a piston rod 8 from the inside of a piston 5 the inside of which is formed to be hollow, and which communicates with the driving chamber through the hollow piston rod 8, a heat accumulating material 21 or 22 is arranged. By doing so, the inside of the piston 5 and the driving chamber communicate with each other in terms of the pressure, but are thermally shut off, and the piston 5 is prevented from being broken, and a heat loss can be prevented from generating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas compression / expansion machine that compresses or expands gas flowing into a cylinder by reciprocating pistons such as a Stirling refrigerator, a Stirling engine, and a Wilmiel heat pump in the cylinder. Regarding

[0002]

2. Description of the Related Art In this type of gas compressor / expander,
In order to reduce the load on the piston drive part and the cost of the piston material, some pistons are hollow inside. However, since the external pressure around the piston becomes a considerably high pressure, the piston is deformed or damaged unless the internal pressure of the piston is kept high to withstand the external pressure. However, it is difficult to assemble the high-pressure gas only inside the piston in terms of assembly work. So conventionally,
In order to improve workability, the piston rod is made hollow, the internal space of the piston communicates with the drive chamber, and high pressure gas is filled into the drive chamber from outside after assembly, so that the internal pressure of the piston becomes the external pressure around the piston. I was trying to keep the pressure to match.

FIG. 5 shows an example of the structure of a gas compression / expansion machine having a hollow piston structure which communicates with such a drive chamber for a Stirling refrigeration machine. The Stirling refrigeration machine mainly comprises the expansion machine 1 and the compressor. 2 and the drive chamber 3. The expander 1 includes an expansion cylinder 4 and an expansion piston 5 that reciprocates in the cylinder. Similarly, the compressor 2 includes a compression cylinder 6 and a compression piston 7 that reciprocates in the cylinder.

The expansion piston 5 and the compression piston 7 are connected to a crank mechanism 10 arranged inside the drive chamber 3 via a piston rod 8 and a piston rod 9, respectively.
It is driven with a phase difference of 90 °.

A regenerator 11 is arranged between the periphery of the expansion cylinder 4 of the expander 1 and the container, and an expansion space 12 formed in front of the expansion piston 5 and a compression space 13 formed in front of the compression piston 7 are arranged via the regenerator. The spaces are communicated with each other by the gas flow path 14, and the gas is moved during the refrigeration cycle. On the other hand, the space on the back pressure side of the expansion piston 5 and the compression piston 7 is connected by the gas flow path 15 in order to prevent the loss of the work of the piston. Radiating fins 16 and 17 are arranged on the outer peripheral surface of the container of the compressor 2 and the outer peripheral surface of the lower portion of the expander 1.

With this configuration, when the crank mechanism 10 of the drive chamber 3 is driven by the rotation of the drive motor (not shown), the compression piston 7 in the compression cylinder 6 of the gas compressor 2 is driven.
Moves toward the compression space 13 and compresses the refrigerant gas such as helium which is difficult to liquefy and fills the compression space 13.

The compressed refrigerant gas flows into the heat storage unit 11 from the gas passage 14. The refrigerant gas that has flowed into the heat storage unit 11 is cooled by a material having a large specific heat, for example, a heat storage material made of copper or lead wire mesh or spheres, and the cooled refrigerant gas flows into the expansion space 12 of the expander 1 and has a high pressure. It becomes a state.

After that, the expansion piston 5 in the expansion cylinder 4 of the expander 1 descends with the phase difference of about 90 ° with the compression piston 7. Thereby, the expansion space 12 is rapidly expanded and the high-pressure refrigerant gas flowing from the heat storage unit 11 into the expansion space 12 is rapidly expanded and the pressure of the refrigerant gas sharply drops, so that the refrigerant gas becomes a low temperature.

Eventually, the expansion piston 5 starts to rise,
When the compression piston 7 retracts, the low-temperature refrigerant gas passes through the heat storage unit 11 and returns to the compression space 13 via the gas flow path 14. At this time, in the heat storage unit 11, the heat storage material is cooled and cold heat is stored.

By the above-mentioned process, one heat cycle is completed, and this process is repeated by the crank mechanism 10, so that the temperature of the freezing generation part which is the expansion space 12 and the temperature of the heat accumulator 11 are gradually lowered, The refrigerant gas in the freezing generation section becomes low in temperature, and the generated cold heat can be taken out and used.

By the way, when the expansion piston 5 and the compression piston 7 are hollow inside, the load, cost and weight of the crank mechanism 10 can be reduced. In this case, the pressure outside the piston becomes considerably high, so that high-pressure gas needs to be enclosed inside the piston. However, it is difficult to pre-charge high-pressure gas only inside the piston in terms of assembly work. Therefore, conventionally, hollow gas passages 18 and 19 are provided inside the piston rods 8 and 9 so as to communicate with the inside of the drive chamber 3, and high pressure gas is sealed from the outside into the drive chamber 3 after assembly, so that the piston 5 , 7 was kept at a high pressure.

[0012]

However, according to the above-mentioned conventional structure, the temperature inside the drive chamber 3 is always maintained by the convection inside the driven pistons 5 and 7. On the other hand, outside the pistons 5 and 7, the tip is maintained at a low temperature of, for example, −200 ° C. and the root is kept at room temperature, and a temperature gradient is formed from the tip to the root. For this reason, in particular, the low temperature at the tip of the piston is transferred to the drive chamber 3 by heat conduction or convection, and the heat loss of the cold heat generated in the expansion space 12 is large, which lowers the thermal efficiency of the gas compression / expansion device. It was

It is an object of the present invention to solve the above problems and provide a gas compressor / expander with good thermal efficiency.

[0014]

In order to achieve the above object, according to claim 1 of the present invention, a piston, which is hollow inside and communicates with a driving chamber through a hollow piston rod, reciprocates in a cylinder. In a gas compression / expansion device that compresses or expands gas flowing into a cylinder by operating, a heat storage material is arranged in at least a part of a gas flow path inside the piston and in the piston rod, which communicates with the drive chamber. It is characterized by having done.

A second aspect of the invention is characterized in that the inside of the piston is filled with the heat storage material according to the first aspect.

According to a third aspect of the present invention, a piston having a hollow interior and communicating with the drive chamber via a hollow piston rod reciprocates in the cylinder to compress or expand the gas flowing into the cylinder. In the gas compression / expansion device, a heat storage material is arranged from the piston rod through the center part of the piston interior to the tip part,
A partition plate that is fitted into the heat storage material and partitions the interior of the piston into a plurality of spaces is arranged, and the spaces are communicated with each other via the heat storage material.

According to a fourth aspect of the present invention, a piston having a hollow interior and communicating with the drive chamber via a hollow piston rod reciprocates in the cylinder to compress or expand the gas flowing into the cylinder. In the gas compression / expansion device, a partition plate provided with a heat storage material is used to partition the inside of the piston into a plurality of spaces, and the spaces are communicated with each other via the heat storage material provided in each partition plate. It is what

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A case where an embodiment of the present invention is applied to a Stirling refrigerator will be described below as an example with reference to the drawings.

FIG. 1 shows a sectional view of an expansion piston 5 in a Stirling refrigerator according to an example of the embodiment of the present invention. The structure other than this piston as a Stirling refrigerator is shown in FIG. Since only the piston portion is shown in FIG. 1, reference is made to FIG. 5 for the rest.

As shown in FIG. 1, in the expansion piston 5 according to the present invention, a heat storage material 21 is provided in a part of a hollow gas passage 18 formed along the axis of a piston rod 8, and a hollow piston is used. 5 is characterized in that the heat storage material 22 is arranged in a portion where the gas passage 18 inside is open. As the heat storage material, for example, stainless steel, ceramic, wire mesh, needle or spherical material such as copper or lead is used. Further, as the gas filled in the piston 5 from the drive chamber 3 through the gas passage 18, helium gas, argon gas or the like can be used.

As described above, by installing the heat storage material in a part of the gas flow path connected from the inside of the expansion piston 5 through the gas passage 18 inside the piston rod 8 to the inside of the drive chamber 3 shown in FIG. The inside of 5 and the inside of the drive chamber 3 can be thermally isolated. That is, due to the reciprocating motion of the piston or the thermal convection, the gas moves between the inside of the expansion piston 5 and the inside of the drive chamber 3, but the gas inside the expansion piston 5 cooled by the cold heat generated in the expansion space 12 accumulates heat. When passing through the materials 22 and 21, the cold heat is stored in the heat storage material and the heat transfer to the drive chamber 3 is blocked. On the other hand, when the gas near the room temperature in the drive chamber 3 passes through the heat storage materials 21 and 22, hot heat is stored in the heat storage material, that is, cold heat is loaded on the gas and heat transfer to the expansion piston 5 is prevented. To be done. As a result, the temperature of the gas inside the expansion piston 5 is maintained near the temperature of the outer peripheral surface of the piston, and the transfer of heat from the expansion space 12 to the expansion piston 5 is blocked. By adopting such a configuration also on the compression piston 7 side, it is possible to obtain a Stirling refrigerator with low heat loss, that is, high thermal efficiency.

FIG. 2 shows another example of the embodiment of the present invention. This example is characterized in that the heat storage material 23 is fully installed only inside the expansion piston 5. In this way, when the entire interior of the expansion piston 5 is arranged so as to be filled with the heat storage material 23, the gas temperature on the inner peripheral surface side of the piston is maintained at a temperature close to the temperature of the outer peripheral surface, and the gas temperature from the outside of the piston to the inside is increased. The transfer of heat is effectively blocked, and a gas compressor / expander with higher thermal efficiency can be obtained. That is, as described above,
On the outer peripheral surface of the expansion piston 5, the piston tip has the lowest temperature and the root is near room temperature, and a temperature gradient occurs from the tip to the root. In the case of the configuration of FIG. 1, since the inside of the expansion piston 5 is maintained at a substantially constant temperature, there is a portion where the temperature difference between the outside and the inside of the piston is somewhat large, and heat transfer occurs there. However, in the case of the configuration of FIG. 2, the heat storage material 23 is filled inside the piston, so that the gas temperature near the piston inner peripheral surface is maintained at a temperature near the piston outer peripheral surface, and the piston inner peripheral surface side is also maintained. A temperature gradient proportional to the outer peripheral surface side is created, and heat transfer from the outer peripheral surface side of the piston to the inner peripheral surface side is more efficiently blocked. As a result,
A Stirling refrigerator having higher thermal efficiency than that of the above example can be obtained.

FIG. 3 shows another example of the embodiment of the present invention. In the case of this example, the gas passage 18 which is a hollow portion of the piston rod 8 passes through the central portion of the inside of the expansion piston 5 and the tip thereof. It is characterized in that the heat storage material 24 is disposed over the portion and a partition plate 26 that is fitted into the heat storage material 24 and partitions the inside of the expansion piston 5 into a plurality of spaces 25 is disposed.

When the expansion piston 5 is constructed in this way, the gas enters and leaves each space 25, which is partitioned by the partition plate 26 inside the expansion piston 5, through the heat storage material 24. Uniformly maintained at a temperature close to the piston external temperature.

Therefore, in the case of the configuration of FIG. 3, compared with the configuration of FIG. 2, the amount of heat storage material used can be saved, the weight can be reduced, and the internal temperature of the piston can be maintained close to the external temperature. A Stirling refrigerator having less heat transfer, that is, better thermal efficiency than the case of the configuration of FIG. 1 can be obtained.

FIG. 4 shows still another example of the embodiment of the present invention. In the case of this example, the heat storage material 27 is provided in the gas passage 18 which is the hollow portion of the piston rod 8. It is characterized in that the inside of the expansion piston 5 is partitioned into a plurality of spaces 30 by a partition plate 29 having a heat storage material 28 arranged in the opening.

When the expansion piston 5 is constructed in this way, the gas flows from the heat storage material 27 disposed in the gas passage 18 inside the piston rod 8 to each partition plate 2 inside the expansion piston 5.
6 enters and leaves each space 25 through each heat storage material 28 provided in 6, and the inside of each space 25 is uniformly maintained at a temperature close to the piston external temperature.

Therefore, in the case of the configuration of FIG. 4, the heat storage material 28 inside the piston is arranged only on the partition plate 29 as compared with the configuration of FIG. 3, so that the amount of heat storage material used can be further saved. A Stirling refrigerator having good thermal efficiency similar to that shown in FIG. 3 can be obtained.

In the above-described embodiment, an example in which the present invention is applied to a Stirling refrigerator has been described, but the present invention is not limited to this, and can be applied to a gas compression / expansion device such as a Stirling engine or a Wilmiel heat pump. It goes without saying that it can be applied.

[0030]

According to the structure of claim 1 of the present invention, although the inside of the piston and the drive chamber communicate with each other in terms of pressure, they are thermally shut off, heat loss is prevented, and gas with good thermal efficiency is provided. A compression / expansion machine can be obtained.

According to the structure of claim 2 of the present invention, the temperature difference between the inner peripheral surface and the outer peripheral surface is reduced over the entire piston, and the heat loss can be prevented more effectively and the thermal efficiency can be further improved as compared with the structure of claim 1. A good gas compressor / expander can be obtained.

According to the structure of claim 3 of the present invention, the temperature is maintained close to the piston outer peripheral surface side for each space partitioned by the partition plate, and the heat loss can be prevented more effectively than the structure of claim 1. In addition, the amount of heat storage material used can be suppressed, and an economically efficient gas compressor / expander with good thermal efficiency can be obtained.

According to the structure of claim 4 of the present invention, the amount of the heat storage material used can be further reduced as compared with the structure of claim 3, and a gas compression / expansion machine which is more economical and has high thermal efficiency can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a piston showing a first example of an embodiment of the present invention.

FIG. 2 is a sectional configuration diagram of a piston showing a second example of the embodiment of the present invention.

FIG. 3 is a sectional configuration diagram of a piston showing a third example of the embodiment of the present invention.

FIG. 4 is a sectional configuration diagram of a piston showing a fourth example of the embodiment of the present invention.

FIG. 5 is a cross-sectional configuration diagram of a conventional Stirling refrigerator.

[Explanation of symbols]

 5 Piston 8 Piston Rod 18 Gas Passage 21, 22, 23, 24, 27, 28 Heat Storage Material 26, 29 Partition Plate 25, 30 Space

Claims (4)

[Claims] 1. A gas compression / compression system that compresses or expands gas flowing into a cylinder by reciprocating a piston having a hollow interior and communicating with a drive chamber via a hollow piston rod. In the expander, a heat storage material is arranged in at least a part of a gas flow path inside the piston and in the piston rod communicating with the drive chamber. 2. The gas compression / expansion machine according to claim 1, wherein the heat storage material is filled inside the piston. 3. A gas compression / compression device for compressing or expanding a gas flowing into the cylinder by reciprocating a piston having a hollow interior and communicating with a drive chamber via a hollow piston rod. In the expander, a heat storage material is arranged from the piston rod through the center portion of the piston to the tip portion, and a partition plate that is fitted to the heat storage material and partitions the inside of the piston into a plurality of spaces is arranged. A gas compression / expansion device, characterized in that the gas is communicated through the heat storage material. 4. A gas compression / compression system for compressing or expanding a gas flowing into the cylinder by reciprocating a piston having a hollow interior and communicating with a drive chamber via a hollow piston rod. In the expander, a partition plate provided with a heat storage material is used to partition the interior of the piston into a plurality of spaces, and the spaces are communicated with each other via the heat storage material provided to each partition plate. Compressor / expander.