JPH11173693A - Two piston type gas compressor/expansion machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent working gas which does not exchange heat with a cold storage material from flowing into an expansion space. SOLUTION: An expansion section 30 is formed to comprise an expansion piston upper section 39, an expansion piston lower section 31 connected to the expansion piston upper section 39 for interlocking, and a communicating space 39b formed between the expansion piston upper section 39 and the expansion piston lower section 31 and continuously connected to a gas passage. According to this arrangement, a pressure difference between the communicating space 39b and an expansion space 33 is caused to be almost the same, so that high temperature working gas of the communicating space 39b does not exchange heat with a cold storage material 51 and flows through a space between the expansion piston upper section 39 and the expansion piston upper cylinder 32a, thereby preventing the working gas from flowing into the expansion space 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reduces the heat loss caused by the flow of a high-temperature working gas which has not exchanged heat with a regenerator material through an upper side wall of an expansion piston into an expansion space. The present invention relates to a two-piston gas compression / expansion machine in which the pressure is improved.

[0002]

2. Description of the Related Art Conventionally, gas compressors / expanders have been used in Stirling refrigerators, Stirling engines, reciprocating compressors and the like.

FIG. 5 shows a schematic configuration of such a gas compression / expansion machine.
1, an expansion section 130 with an expansion piston 131, and a drive section 14 with a crank mechanism 143.
0, having a cold storage unit 150 in which a cold storage material 151 is stored,
The cold storage section 150 is provided in the middle of a gas flow path 161 that connects the compression section 120 and the expansion section 130.

The compression section 120 includes a compression cylinder 122 for accommodating a compression piston 121, a compression space 123 provided on the head side of the compression cylinder 122, and a compression piston 121.
Buffer space 124 formed by the
The compression piston 121 includes a buffer chamber 125 communicating with the buffer space 124, a compression piston rod 126 for transmitting driving force to the compression piston 121 through the partition 163, and the like. An oil seal 128 is provided on the piston rod 126.

The expansion section 130 includes an expansion cylinder 132 for accommodating an expansion piston 131, an expansion space 133 provided on the head side of the expansion cylinder 132, and an expansion piston 131.
Buffer space 134 formed by the
It has an expansion piston rod 136 and the like for transmitting a driving force to the expansion piston 131 through the buffer chamber 135 and the partition 163 communicating with the buffer space 134. The expansion piston 131 is provided with a gas seal 137. An oil seal 138 is provided on the piston rod 136.

Radiation fins 164 are provided around the compression cylinder 122 and the like to radiate the heat of the working gas generated by the compression to the outside. A load 162 is mounted on the head side of the expansion cylinder 132.

[0007] The buffer spaces 124 and 134 and the buffer chambers 125 and 135 are filled with working gas.

The drive unit 140 includes a crank mechanism 143 comprising cranks 142a and 142b fixed to a rotor 141, a shaft 146, a storage tank 147 for storing oil for lubricating the crank mechanism 143 and the like, a crank mechanism 143, and a compression mechanism. Connecting rod 144a and cross guide 145 connected to piston rod 126
a, Crank mechanism 143 and expansion piston rod 136
A connecting rod 144b, a cross guide 145b, and the like, which are connected to the control rod.

In such a configuration, when the crank mechanism 143 rotates, the rotating power is reduced by the connecting rod 1.
It is transmitted to the compression piston 121 and the expansion piston 131 via 44a, 144b and the like.

At this time, the two cranks 142a, 142
b indicates that the shaft 146 moves so that the expansion piston 131 reciprocates with a phase approximately 90 degrees ahead of the compression piston 121.
It is fixed to.

While the compression piston 121 moves from the bottom dead center to the top dead center, the expansion piston 131 reaches the top dead center and moves downward. At this time, the working gas in the compression space 123 is adiabatically compressed and the temperature rises.
The heat is radiated to the atmosphere by the heat radiation fins 164 formed in the surroundings, and as a result, it can be regarded as isothermal compression.

The working gas in the compression space 123 flows through the gas passage 161 and moves toward the expansion space 133 while exchanging heat in the regenerator 150 together with the downward movement of the expansion piston 131, and the expansion piston 131 moves to the bottom dead center. As the distance approaches, the adiabatic expansion occurs, and the temperature of the working gas decreases.

The working gas, whose temperature has been lowered due to the upward movement of the expansion piston 131, flows through the gas passage 161 while cooling the load 162, exchanges heat in the regenerator 150 and returns to the compression space 123 for one cycle. Ends.

When the compression piston 121 and the expansion piston 131 reciprocate, the buffer chambers 124, 13
Space 4 acts to hinder the reciprocation,
The drive section 140 must drive the compression piston 121 and the like with a large force.

Therefore, the power supplied to the drive unit 140 increases, and the ratio of the amount of heat taken from the load 162 to the supplied power decreases. Since the lowering of the ratio becomes larger as the buffer spaces 124 and 134 become smaller, the buffer chambers 125 and 135 are conventionally provided separately.

[0016]

However, the expansion piston 131 and the expansion cylinder 1 are provided by the gas seal 137.
Although the working gas is prevented from flowing from the buffer space 134 to the expansion space 133 by bringing the working gas 32 into close contact with the expansion space 133, it is physically difficult to completely eliminate the flow.

For this reason, when the pressure difference between the expansion space 133 and the buffer space 134 is increased, the flow of the working gas occurs between them and there is a problem that the ability to cool the load 162 is reduced.

That is, when the volume of the expansion space 133 is largest, the volume of the buffer space 134 is smallest, and a large differential pressure is generated. Therefore, the buffer space 13
The working gas flows from 4 into the expansion space 133.

The temperature of the working gas in the buffer space 134 is
Since the temperature of the working gas which has been expanded in the expansion space 133 is lower than the temperature of the working gas, the temperature of the working gas in the expansion space 133 rises due to the flow of the working gas, and the ability to cool the load 162 decreases. .

Accordingly, an object of the present invention is to provide a gas compression / expansion machine in which such a decrease in cooling capacity is prevented.

[0021]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to an invention according to claim 1, wherein a driving unit and a reciprocating motion receiving driving force from the driving unit reciprocate to form a compressed space in the compression space. A compression section for compressing the working gas, an expansion section for expanding the working gas in the expansion space by reciprocating with a phase shift of approximately 90 degrees from the compression section, and a working gas communicating the compression section and the expansion section. In a two-piston gas compression / expansion machine having a gas flow path forming a flow path, a compression section and an expansion section are arranged in a row and provided in a drive section.

An upper portion of the expansion piston containing the regenerator material, a lower portion of the expansion piston connected to the upper portion of the expansion piston, and a communication space formed between the upper portion of the expansion piston and the lower portion of the expansion piston and communicating with the gas flow path. This constitutes the expansion section.

The working gas flowing from the compression section into the communication space via the gas flow path passes through the upper portion of the expansion piston while exchanging heat with the cold storage material, and flows into the expansion space.
The expansion space is expanded by the expansion piston upper part and the expansion piston lower part so that the working gas expands.

With this arrangement, the differential pressure between the communication space and the expansion space is set to substantially the same pressure, and the working gas in the high-temperature communication space that does not exchange heat with the cold storage material expands via the side wall above the expansion piston. It is characterized in that it is prevented from flowing into the space.

According to a second aspect of the present invention, there is provided a compression unit comprising a compression piston for compressing a working gas, a compression cylinder for reciprocally storing the compression piston, and a radiating fin disposed to cover the compression cylinder. Is configured.

A gap is formed between the radiation fin and the compression cylinder, and when the working gas flows using the gap as a gas flow path, heat of the working gas is efficiently radiated. It is characterized by.

According to a third aspect of the present invention, there is provided an expansion piston lower cylinder for reciprocatingly storing an expansion piston lower part,
The radiating fins arranged to cover the lower cylinder of the expansion piston constitute an expansion section.

A gap formed between the radiation fin and the lower cylinder of the expansion piston forms a gas flow path.
It is characterized in that the heat of the working gas flowing through the gas flow path is efficiently radiated.

According to a fourth aspect of the present invention, a groove is formed in the gas flow path opening on the communication space side so that the communication space always communicates with the gas flow path even when the expansion piston upper part and the expansion piston lower part reciprocate. It is characterized by having been formed.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a two-piston gas compression / expansion machine according to the present embodiment.

The two-piston type gas compression / expansion machine includes a driving unit 40 having a crank mechanism 43 composed of cranks 42a and 42b, an expansion unit 30 having an expansion piston lower part 31 and an expansion piston upper part 39, and a compression piston 21. And the like.

The drive section 40 includes a rotor 41 for applying a rotational driving force to the crank mechanism 43, a storage tank 47 for storing oil for lubricating the crank mechanism 43, a crank 42a,
Connecting rods 44a, 44 connected to 42b
b, cross guides 45a and 45b for converting the driving force from the connecting rods 44a and 44b into linear motion.

The crank 42a and the crank 42b are eccentrically connected to the shaft 46, and the phase of the compression piston 21 is delayed by about 90 degrees with respect to the phase of the expansion piston lower part 31.

The expansion section 30 includes an expansion piston lower part 31 and an expansion piston upper part 3 connected to the expansion piston lower part 31.
9, an expansion cylinder 32 (32a, 32) for reciprocatingly storing the expansion piston upper part 39 and the expansion piston upper part 31.
b), an expansion space 33 and an expansion piston lower part 31 provided on the head side (upper side in FIG. 1) of the expansion cylinder 32
, A buffer chamber 35 communicating with the buffer space 34, and a lower portion of the expansion piston 3
A load 62 is mounted on the head of the expansion cylinder 32 and the like.

The expansion cylinder 32 is an expansion piston upper cylinder 32 in which the expansion piston upper part 39 reciprocates.
a and an expansion piston lower cylinder 32b in which an expansion piston lower part 31 reciprocates.

A cold storage material 51 is accommodated in the upper part of the expansion piston 39, and a large number of communication holes 39a for communication with the expansion space 33 are provided in the upper end surface thereof.

A communication space 39b for communicating the gas flow path G2 with the upper part of the expansion piston 39 is formed at the connection between the upper part 39 of the expansion piston and the lower part 31 of the expansion piston.

Accordingly, the working gas flows into the communication space 39b from the gas flow path G2, exchanges heat with the cold storage material 51, and flows out from the communication hole 39a to the expansion space 33. When flowing from the expansion space 33 to the gas flow path G2, it flows through the reverse flow path.

Gas seals 37a and 37b are provided on the expansion piston upper portion 39 and the expansion piston lower portion 31 to enhance the close contact between these gas seals and the expansion piston upper cylinder 32a and the expansion piston lower cylinder 32b.

The expansion piston rod 36 and the partition 63
An oil seal 38 is provided between the
Is prevented from entering the expansion section 30.

The compression section 20 is formed on a compression cylinder 22 for accommodating a compression piston 21, a compression space 23 provided on the head side (upper side in FIG. 1) of the compression cylinder 22, and a back pressure side of the compression cylinder 22. It has a buffer space 24, a buffer chamber 25 communicating with the buffer space 24, and the like.

A gas seal 27 is provided on the compression piston 21 so that the compression piston 21 and the compression cylinder 22
And an oil seal 28 is provided between the compression piston rod 26 and the partition 63 to prevent the oil of the drive unit 40 from entering the compression unit 20.

Further, around the compression cylinder 22 and the expansion piston lower cylinder 32b, radiating fins 64 for radiating the heat of the working gas to the outside are arranged so as to cover them.

FIG. 1 shows a case where the radiation fins 64 are formed to surround the compression cylinder 22 and the expansion piston lower cylinder 32b.
The present invention is not limited to this, and the radiation fins may be formed so as to surround only the periphery of the compression cylinder 22. Of course, in this case, it goes without saying that a similar heat radiation fin may be provided around the lower cylinder of the expansion piston.

By forming the radiation fins so as to independently surround the periphery of the compression cylinder 22 and the like, the area of the radiation fins can be increased, and the heat of the working gas transfers heat to the radiation fins. Since the average distance can be reduced, heat can be efficiently dissipated. Therefore, when the gas compression / expansion machine is used in a refrigerator or the like, the coefficient of performance can be increased.

FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, wherein a cylindrical gas flow path G 1 is formed between the radiation fin 64 and the compression cylinder 22, and the radiation fin 64 and the expansion piston lower cylinder 32 b are connected to each other. A gas flow path G2 having a cylindrical shape is formed therebetween, and the gas flow paths G1 and G2 are connected by a gas flow path G3 so that the compression section 20 and the expansion section 30 communicate with each other.

The compression section 20 and the expansion section 30 are disposed in the same direction, and the driving section 40
To reduce the space occupied by the two-piston gas compression / expansion machine.

Next, the operation of the gas compressor / expander based on the above configuration will be described with reference to FIG.

FIG. 3A shows a state in which the lower portion 31 of the expansion piston moves downward and approaches the bottom dead center, and FIG.
Shows a state when the lower part 31 of the expansion piston moves upward and approaches the top dead center. In the drawing, the solid arrow indicates the direction in which the expansion piston lower part 31 moves, and the dotted arrow indicates the flow direction of the working gas at that time.

When the crank mechanism 43 rotates,
The rotating power is transmitted to the compression piston 21 and the expansion piston lower part 31 via the connecting rods 44a, 44b and the like.

As a result, the compression piston 21 reciprocates with a phase delayed by about 90 degrees with respect to the expansion piston lower part 31. As described above, since the upper portion 39 of the expansion piston is connected to the lower portion 31 of the expansion piston, the upper portion 39 of the expansion piston also moves with a phase advanced by about 90 degrees from the compression piston 21.

When the compression piston 21 moves from the bottom dead center to the top dead center, the working gas in the compression space 23 is compressed. During this time, the lower part of the expansion piston 31 moves upward and reaches the top dead center, and then moves downward.

The working gas compressed by the upward movement of the compression piston 21 flows through the gas flow paths G1, G3 and G2 while being radiated by the radiation fins 64 and is sent to the expansion section 30.

When the lower part of the expansion piston 31 moves downward, the upper part of the expansion piston 39 moves downward together with the lower part of the expansion piston 31, so that the working gas flows into the upper part of the expansion piston 39 from the communication space 39 b and exchanges heat with the cold storage material 51. Then, it flows out from the communication hole 39a into the expansion space 33 (see FIG. 3A).

At this time, since the volume of the expansion space 33 is expanded by the downward movement of the expansion piston lower portion 31, the working gas expands and its temperature decreases. That is, the load 62 can be cooled.

The pressure in the expansion space 33 and the pressure in the communication space 39b are only the pressure difference generated by the cold storage material 51, and the pressure difference is small, and the working gas flowing due to the pressure difference is always the cold storage material 51. Therefore, the working gas in the communication space 39b having a high temperature does not directly flow into the working gas whose temperature has been lowered by expansion. Therefore, a decrease in the ability to cool the load 62 can be prevented.

In this case, complete sealing by the gas seal 37a is not required, and it is sufficient that the conductance is sufficiently smaller than the conductance of the cold storage material 51. Since such conditions can be easily achieved, the configuration of the gas seal 37a can be simplified.

Further, since the expansion space 33 and the communication space 39b have substantially the same pressure, the pressure resistance of the upper part 39 of the expansion piston may be low.

Therefore, the upper portion 39 of the expansion piston has a low thermal conductivity such as resin, so that a lightweight member can be used to prevent heat from entering the upper portion 39 of the expansion piston from the upper cylinder 32a of the expansion piston. This makes it possible to reduce the weight and cost of the apparatus.

Thereafter, as the compression piston 21 approaches the bottom dead center, the expansion piston lower part 31 starts to move upward, the working gas flows in the expansion piston upper part 39 and exchanges heat with the cold storage material 51, and from the communication space 39. Returning to the compression space 23 via the gas flow paths G2, G3, and G1, the cycle ends (FIG. 3).
(B)).

In the above configuration, the lower part of the expansion piston 3
The size of the communication space 39b is set so that the lower and upper expansion pistons 31 and 39 do not block the gas flow path G2 when 1 or the like moves up and down.

That is, as can be easily understood from FIG. 3A, the height h1 of the communication space 39b is set such that the stroke of the lower part of the expansion piston 31 is S and the size of the opening of the gas passage G2 is h2. At this time, h1 ≧ S + h2 is set.

At this time, the height h1 of the communication space 39b is
Unnecessary space is provided for the stroke. In such a case, as shown in FIG. 4, the unnecessary space is formed by forming a groove M in the opening of the gas flow path G2 on the communication space 39b side. It can be removed.

FIG. 4 is a view corresponding to FIG. 3, and FIG. 4 (a) shows that when the lower part 31 of the expansion piston approaches the bottom dead center, FIG.
(B) shows the flow of the working gas when the expansion piston lower part 31 approaches the top dead center.

The groove M may be formed not only at the opening of the gas flow path G2 but also at the expansion piston upper portion 39 and the expansion piston lower portion 31.

[0066]

As described above, according to the first aspect of the present invention, the expansion portion is constituted by the upper portion of the expansion piston, the lower portion of the expansion piston, and the communication space. The working gas that has flowed into the communication space passes through the upper portion of the expansion piston and flows into the expansion space while exchanging heat with the cold storage material, and the expansion space is expanded by the upper portion of the expansion piston to expand the working gas. As a result, it is possible to make the pressure difference between the communication space and the expansion space substantially the same, and the high-temperature working gas in the communication space and the like does not exchange heat with the cold storage material and passes through the upper side wall of the expansion piston. So that it does not flow into the expansion space.

As a result, the size and cost of the apparatus can be reduced, and when the apparatus is used in a refrigerator or the like, the result count can be increased.

According to the second aspect of the present invention, since the radiation fins are provided so as to cover the compression cylinder, it is possible to efficiently radiate the heat of the working gas to the outside.

According to the third aspect of the present invention, since the radiation fins are provided so as to cover the lower cylinder of the expansion piston, it is possible to efficiently radiate the heat of the working gas to the outside.

According to the fourth aspect of the present invention, since the groove is formed in the gas flow path opening on the communication space side, the communication space and the gas flow path are always in communication.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a two-piston gas compression / expansion machine applied to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a view showing a flow direction of a working gas accompanying an operation of a lower portion of an expansion piston in an expansion section.

FIG. 4 is a diagram corresponding to FIG. 3 when a groove is provided in a gas flow path.

FIG. 5 is a cross-sectional view of a two-piston gas compression / expansion machine applied to the description of the related art.

[Explanation of symbols]

 Reference Signs List 20 compression unit 21 compression piston 22 compression cylinder 23 compression space 24 buffer space 25 buffer chamber 27, 37a, 37b gas seal 28, 38 oil seal 30 expansion unit 31 expansion piston lower part 32a expansion piston lower cylinder 32b expansion piston lower cylinder 33 expansion space 34 Buffer Space 35 Buffer Chamber 39 Upper Expansion Piston 39a Communication Hole 39b Communication Space 40 Drive Unit 43 Crank Mechanism 64 Radiating Fin G1, G2, G3 Gas Flow Path

Claims (4)

[Claims] 1. A driving section, a compression section for compressing a working gas in a compression space by reciprocating by receiving a driving force from the driving section, and reciprocating with a phase shift of about 90 degrees from the compression section. A two-piston gas compression / compression system having an expansion part for expanding the working gas in the expansion space and a gas flow path forming a flow path for the working gas by connecting the compression part and the expansion part.
In the expander, the compression section and the expansion section are provided in the drive section in a row, and the expansion section is connected to an upper portion of an expansion piston containing a cold storage material and to an upper portion of the expansion piston. An expansion piston lowering the working gas in the expansion space, and a communication space formed between the expansion piston upper part and the expansion piston lower part and communicating with the gas flow path; The working gas flowing into the communication space through the gas flow passage passes through the upper part of the expansion piston and flows into the expansion space while exchanging heat with the cold storage material, and the upper part of the expansion piston and the lower part of the expansion piston A two-piston type gas compression / expansion machine characterized in that the expansion space expands and the working gas expands. 2. The compression section has a compression piston for compressing a working gas, a compression cylinder for reciprocally storing the compression piston, and a radiation fin disposed to cover the compression cylinder. 2. The gap according to claim 1, wherein a gap formed between the radiation fin and the compression cylinder forms a gas flow path and radiates heat of the working gas flowing through the gas flow path. Piston type gas compression / expansion machine. 3. The expansion section has an expansion piston lower cylinder for reciprocatingly housing the expansion piston lower part, and a radiation fin arranged to cover the expansion piston lower cylinder. The gap according to claim 1 or 2, wherein a gap formed between the expansion piston and the lower cylinder forms a gas flow path and radiates heat of the working gas flowing through the gas flow path. Piston type gas compression / expansion machine. 4. A groove is formed in the gas flow path opening on the communication space side so that the communication space and the gas flow path always communicate even when the upper and lower expansion pistons reciprocate. The two-piston gas compression / expansion machine according to any one of claims 1 to 3, wherein: