JPH0996454A - 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: A hollow part in a piston 5 communicates with a driving chamber 3 through a gas passage 18 which goes through the inside of a piston rod 8. At the same time, in the gas passage 18 which goes through the inside of the piston rod 8 or in the vicinity of the opening, a sealing mechanism 20 which shuts off the stream of the gas at least when the piston 5 is operating, is provided. By doing so, the gas passage between the inside of the piston 5 and the driving chamber is shut off, and a heat loss is prevented from generating by shutting off a heat moving due to the moving of the gas, and a gas compressing/expanding machine of a favorable thermal efficiency can be obtained.

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 which compresses or expands gas flowing into a cylinder by reciprocating a piston 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 the 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 flowing into the heat storage device 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 that has flowed into the expansion space 12 from the heat storage unit 11 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 / expander. 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 hollow portion inside a piston communicates with a driving chamber through a gas passage penetrating the inside of a piston rod, and the driving thereof is performed. In a gas compression / expansion device that compresses or expands gas flowing into a cylinder by reciprocating the piston in the cylinder driven by a driving mechanism in a chamber, a gas passage penetrating the inside of the piston rod inside the piston. Or near that opening,
It is characterized in that a seal mechanism for cutting off the flow of gas at least when the piston is operated is provided. Further, with this configuration, the gas passage between the inside of the piston and the drive chamber is blocked, heat transfer due to gas movement is blocked, heat loss is prevented, and a gas compression / expansion device with high thermal efficiency is obtained. .

A second aspect of the present invention is characterized in that the sealing mechanism according to the first aspect uses heat contraction to shut off the gas passage or the vicinity of the opening thereof due to a temperature decrease during piston operation. Further, with this configuration, in addition to the effect of the first aspect, the effect that the gas sealing mechanism can be realized with a simple configuration by using the heat-shrinkable body is obtained.

A third aspect of the present invention is characterized in that the sealing mechanism according to the first aspect uses thermal expansion to shut off the gas passage or the vicinity of the opening thereof due to a temperature rise during piston operation. Is. Further, with this configuration, in addition to the effect according to the first aspect, it is possible to obtain the effect that the gas sealing mechanism can be realized with a simple configuration by using the thermal expansion body.

A fourth aspect of the present invention is characterized in that the sealing mechanism according to the first aspect is configured to shut off the gas passage or the vicinity of the opening thereof by utilizing a spring force. With this configuration, in addition to the effect of the configuration of claim 1,
The effect that the gas seal mechanism can be realized with a simple structure using the spring is obtained.

A fifth aspect of the invention is characterized in that a check valve is used as the sealing mechanism according to the first aspect.
Further, with this configuration, in addition to the effect of the first aspect, it is possible to easily achieve gas sealing by arranging the check valve at an appropriate position of the piston rod.

[0019]

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 an embodiment of the present invention. The structure other than this piston as a Stirling refrigerator is shown in FIG. Since FIG. 1 is the same, only the piston portion is shown in FIG.

As shown in FIG. 1, the expansion piston 5 according to the present invention is characterized in that a seal mechanism 20 for closing the opening of the gas passage 18 inside the piston 5 when the piston is activated is provided. Have.

The seal mechanism 20 is shown in detail in FIG.
As shown in (A) an enlarged sectional view taken along the line AA, (B) an enlarged sectional view before operating the refrigerator, and (C) an enlarged sectional view during operation of the refrigerator, the piston rod 8 is attached to the piston end plate 5a. It penetrates and projects inside the piston, and the piston rod projection 2
Seal plate 2 whose top surface is supported by heat-shrinkable support 22
3, the contraction of the column 22 is used to close the Stirling refrigerator during operation.

That is, as shown in FIG. 2, the piston end surface 5
Four pillars 22 are planted on the surface a, which support the seal plate 23 so as to surround the outer peripheral surface of the piston rod protrusion 21 and in this example.

The column 22 is made of a material having a good heat shrinkability, which shrinks as the ambient temperature decreases.
In addition, the lower surface of the seal plate 23, that is, the piston rod protrusion 2
The first side is formed with a recess 23a into which the upper surface of the protrusion 21 is fitted.

By providing the seal mechanism 21 having such a structure at the portion where the gas passage 18 is opened on the piston end surface 5a, as shown in FIG. 2 (B), when high pressure gas is charged before the Stirling refrigerator is operated. The high pressure gas is filled into the expansion piston 5 from the upper surface of the protrusion 21 through the gas passage 18 of the piston rod 8.

Next, when the temperature of the upper portion of the piston 5 is lowered and the gas inside the piston is cooled during the operation of the Stirling refrigerator as described above, the column 22 is also cooled and contracts, as shown in FIG. 2 (C). Thus, the seal plate 23 descends and the upper surface of the protrusion 21 fits into the recess 23a of the seal plate to close the opening of the gas passage 18.

As a result, the inside of the expansion piston 5 and the drive chamber 3
The movement of gas with the inside is blocked, and the heat transfer due to the gas is blocked. Therefore, the temperature of the gas inside the piston is maintained near the temperature of the outer peripheral surface of the piston, the transfer of heat from the expansion space 12 to the expansion piston 5 is blocked, and there is little heat loss, that is, a Stirling refrigerator with good thermal efficiency. Will be obtained.

FIGS. 3 and 4 show another example of the embodiment of the present invention, which is an example when applied to the compression piston 7 of FIG. 8, and a configuration as a Stirling refrigerator other than the compression piston 7 is shown. Since it is the same as the configuration shown in FIG. 8, only the piston portion is shown in the figure and FIG.

In the case of this example, the sealing mechanism 20 provided at the opening of the gas passage 18 on the piston end face 7a inside the compression piston 7 surrounds the periphery of the opening of the gas passage 18 and is provided on the upper surface.
The coating 24 having the gas passage hole 24a is attached to the piston end surface 7
It is configured to be fixed on a and accommodate the thermal expansion body 25 inside.

With this structure, when the high pressure gas is filled before the refrigerator is operated, the thermal expansion body 25, the piston end surface 7a and the coating body 2 are provided.
4 has a gap between it and the upper surface,
As shown in (A), the high-pressure gas flowing in from the gas passage 18 pushes away the thermal expansion body 25, flows into the compression piston 7 from the gas passage hole 24 a of the covering body 24, and is filled therein.

Next, during operation of the Stirling refrigerator, as shown in FIG. 4B, heat is generated at the tip of the piston 7 and the gas inside the piston is heated, so that the thermal expander 25 expands and the piston expands. The gap between the end surface 7a and the cover 24 is closed.

As a result, the inside of the compression piston 7 and the drive chamber 3
The movement of gas with the inside is blocked, and the heat transfer due to the gas is blocked. Therefore, the temperature of the gas inside the piston is maintained near the temperature of the outer peripheral surface of the piston, the transfer of heat from the compression space 13 to the compression piston 7 is blocked, and there is little heat loss, that is, a Stirling refrigerator with good thermal efficiency. Will be obtained.

Further, by constructing the Stirling refrigerator shown in FIG. 8 using the expansion piston 5 and the compression piston 7 according to the present invention, the heat loss on both the low temperature side and the high temperature side can be effectively suppressed and the thermal efficiency can be improved. A Stirling refrigerator can be obtained.

FIG. 5 shows another example of the embodiment of the present invention. In this example, the seal mechanism 20 is
A covering plate 26 that surrounds the periphery of the opening of the gas passage 18 inside the piston 5 and has a cover 24 having a gas passage hole 24a fixedly provided on the piston end surface 5a on the upper surface and closing the opening inside, the closing plate 26. It is characterized in that a spring 27 that presses the plate 26 from the cover 24 side to the piston end surface 5a side is housed.

With this structure, when high pressure gas is charged before the refrigerator is operated, the pressure of the high pressure gas fed into the drive chamber 3 is reduced by the spring 27 because the pressure inside the piston 5 is low as shown in FIG. 6 (A). The blocking plate 26 is pushed up by overcoming the pressing force, and the piston 5 passes through the gas passage hole 24a of the covering body 24.
Filled inside.

When the high pressure gas is filled in the piston 5 to increase the internal pressure and approaches the gas pressure sealed in the drive chamber 3, the internal pressure of the piston 5 and the pressing force of the spring 27 cause the internal pressure of the drive chamber 3 to rise. The closing plate 26 is pressed against the piston end surface 5a side over the gas pressure to close the opening of the gas passage 18.

At this time, the internal pressure of the piston 5 and the pressing force of the spring 27 are temporarily changed to the drive chamber 3 by giving the pressing force of the spring 27 a hysteresis characteristic or by embedding a magnet in the closing plate 26 and the piston end surface 5a. If the gas pressure becomes higher than the internal gas pressure, the closing plate 26 can be prevented from opening later.
Therefore, when operating the refrigerator, as shown in FIG.
The opening of the gas passage 18 is closed by the closing plate 26 to block the movement of gas between the inside of the compression piston 7 and the inside of the drive chamber 3,
It is possible to prevent heat transfer due to gas. Thereby, even when the seal mechanism 20 of FIG. 5 is used, the gas temperature inside the piston is kept substantially close to the temperature of the outer peripheral surface of the piston, heat transfer from the compression space 13 to the compression piston 7 is blocked, and heat loss occurs. It is possible to obtain a Stirling refrigerator with less heat consumption, that is, good thermal efficiency.

In the embodiment described above, the seal mechanism 20 is installed in the gas passage 1 on the piston end faces 5a, 7a.
Although an example in which it is provided so as to surround 8 and 19 is shown,
The place where the sealing mechanism 20 is provided is not limited to this,
For example, as shown in FIG. 7, it may be provided in the gas passages 18 and 19 in the piston rods 8 and 9. The seal mechanism 20 can also be configured by using a check valve.

Further, 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 machine such as a Stirling engine or a Wilmiel heat pump. It goes without saying that it can be applied.

[0040]

According to the structure of claim 1 of the present invention, the gas passage between the inside of the piston and the drive chamber is cut off, the heat transfer due to the movement of the gas is cut off to prevent heat loss, and the gas with high thermal efficiency is provided. A compression / expansion machine can be obtained.

According to the structure of claim 2 of the present invention, in addition to the effect of the structure of claim 1, the effect that the gas seal mechanism can be realized with a simple structure by using the heat-shrinkable body is obtained.

According to the structure of claim 3 of the present invention, in addition to the effect of the structure of claim 1, the effect that the gas sealing mechanism can be realized with a simple structure by using the thermal expansion body is obtained.

According to the structure of claim 4 of the present invention, in addition to the effect of the structure of claim 1, the effect that the gas seal mechanism can be realized with a simple structure by using the spring is obtained.

According to the structure of claim 5 of the present invention, in addition to the effect of the structure of claim 1, the effect of enabling a simple gas seal by disposing a check valve at an appropriate position of the piston rod. Is 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 an enlarged detailed view of the seal mechanism shown in FIG.
1A is a cross-sectional view taken along the line AA of FIG. 1, FIG. 1B is a cross-sectional view of a sealing mechanism before operating the refrigerator, and FIG.

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

FIG. 4 is an enlarged detailed view of the sealing mechanism shown in FIG.
FIG. 4B is a sectional view of the sealing mechanism before the operation of the refrigerator, and FIG. 7B is a sectional view of the sealing mechanism during operation of the refrigerator.

FIG. 5 is a sectional configuration diagram of a piston showing another example of the embodiment of the present invention.

FIG. 6 is an enlarged detailed view of the sealing mechanism shown in FIG.
FIG. 4B is a sectional view of the sealing mechanism before the operation of the refrigerator, and FIG. 7B is a sectional view of the sealing mechanism during operation of the refrigerator.

FIG. 7 is a sectional configuration diagram of a piston showing still another example of the embodiment of the present invention.

FIG. 8 is a cross-sectional configuration diagram of a conventional Stirling refrigerator.

[Explanation of symbols]

 5, 7 Piston 8, 9 Piston rod 18, 19 Gas passage 20 Seal mechanism 21 Piston rod protrusion 22 Heat-shrinkable strut 23 Seal plate 24 Cover 25 Heat expander 26 Closure plate 27 Spring

Claims (5)

[Claims] 1. A hollow portion inside a piston communicates with a drive chamber through a gas passage penetrating the inside of a piston rod, and a piston is reciprocated in a cylinder driven by a drive mechanism inside the drive chamber. In a gas compressor / expander for compressing or expanding gas flowing into a cylinder, at least a gas passage penetrating the inside of the piston rod inside the piston or a vicinity of an opening thereof, which seals at least a flow of gas during piston operation. A gas compressor / expander with a mechanism. 2. The gas compression / expansion machine according to claim 1, wherein the sealing mechanism uses heat contraction to shut off the gas passage or the vicinity of an opening thereof due to a temperature decrease during piston operation. 3. The gas compression / expansion machine according to claim 1, wherein the sealing mechanism utilizes thermal expansion to shut off the gas passage or the vicinity of an opening thereof due to a temperature rise during piston operation. 4. The gas compressor / expander according to claim 1, wherein the sealing mechanism shuts off the gas passage or the vicinity of the opening thereof by utilizing a spring force. 5. The gas compression / expansion device according to claim 1, wherein a check valve is used as the sealing mechanism.