JPH11337208A - Stirling cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress air biting by a pump for cooling water even when air slightly gathers in a cooling water piping. SOLUTION: A heat-exchanger 46 for radiation to effect heat-exchange between working gas having temperature increased through compression by a compression chamber 37 is arranged in a gas flow passage 48. Further, a radiator 55 to radiate the heat of cooling water heat-exchanged by the heat-exchanger 46 for radiation is provided. The lower end of the radiator 55 and the lower end part of the heat-exchanger 46 for radiation arranged in a position higher than the level of the lower end part of the radiator 55 are intercoupled through a cooling water piping 54. A pump P1 for cooling water circulated through the forced feed of cooling water to the radiator 55 from a heat-exchanger 46 for radiation. This constitution suppresses air biting by a pump P1 for cooling water even when air gathers in the cooling water piping 54 due to an unexpected reason.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Stirling cooling device using a Stirling refrigerator, and more particularly, to cooling of a working gas by preventing a pump from biting air even if some air is stored in a cooling water pipe. The present invention relates to a Stirling cooling device capable of reliably performing the above.

[0002]

2. Description of the Related Art A Stirling refrigerator used in a Stirling cooling apparatus generates cold by compressing and expanding a working gas.

Such a Stirling cooler has a compression section provided with a compression piston for compressing the working gas in the compression chamber, an expansion section provided with an expansion piston for expanding the working gas in the expansion chamber, and the like. The chamber is communicated with a gas flow path.

The gas flow path is provided with a heat radiating heat exchanger that cools the working gas that has been compressed and has a high temperature. The Stirling refrigeration is performed by lowering the temperature of the working gas flowing from the compression chamber to the expansion chamber. The refrigeration efficiency of the machine.

At this time, in order to enhance the heat radiation efficiency of the heat radiation heat exchanger, for example, a radiator for exchanging heat of the cooling water with the outside air or the like is provided. The heat radiating heat exchanger and the radiator are connected by a cooling water pipe, and the cooling water is circulated by being pumped by a cooling water pump.

[0006]

However, there is a case where air accumulates in the cooling water pipe due to an unexpected reason, and the cooling water pump is not able to properly circulate the cooling water due to air biting. In such a case, the heat of the working gas sent from the compression chamber to the expansion chamber cannot be sufficiently dissipated, so that the refrigeration efficiency of the Stirling refrigerator is reduced.

That is, the cooling water pipes are connected at various places by means such as welding. As a matter of course, the connecting portion is designed so as to be properly connected so as not to cause water leakage or the like, and is inspected. However, a minute defect such as a pinhole may not be detected.

[0008] Such a pinhole is originally assumed at the design stage, and the apparatus is designed with the allowable range. For example, when a Stirling refrigerator is used at a low pressure such as a high altitude, dust or the like is generated in a radiator. If the temperature of the cooling water rises abnormally and the pressure inside the cooling water piping rises, the amount of water leakage from the pinholes increases, In some cases, air may accumulate in the cooling water piping.

At this time, if the cooling water pump is provided at a position higher than the upper end portion of the heat radiating heat exchanger and the upper end portion of the radiator, the cooling water pump bites the air stored in the cooling water pipe and idles. Will be done.

Therefore, cooling water cannot be circulated,
A situation occurs in which the Stirling refrigerator cannot exhibit a predetermined refrigerating capacity due to a decrease in the circulation amount.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a Stirling cooling device which suppresses the cooling water pump from biting air even when some air is stored in the cooling water pipe.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a compression piston for compressing a working gas in a compression chamber, and a reciprocating motion of the compression piston which is out of phase with the compression piston by about 90 to form an expansion chamber. In a Stirling cooling device having an expansion piston for expanding a working gas, a gas passage connecting a compression chamber and an expansion chamber, and connecting the working gas between them, the Stirling cooling device includes Provided,
A heat-dissipating heat exchanger for exchanging heat between the working gas, which has been heated in the compression chamber and the temperature of which has risen, and cooling water; A cooling water pipe is provided in the middle of a cooling water pipe connecting the lower end and the lower end of a heat radiating heat exchanger provided at a position higher than the lower end of the radiator, and pumps cooling water from the radiator to the heat radiating heat exchanger. And a cooling water pump for circulating the cooling water to prevent the cooling water pump from biting the air even if air is stored in the cooling water pipe for an unexpected reason.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a Stirling cooling device according to the present invention.
In the figure, a Stirling refrigerator 3 is provided inside a box-shaped case 2.

Further, a cooling head 4 is provided in the Stirling refrigerator 3, and a cooling / cooling refrigerant pipe 5 is connected to the cooling head 4, so that cooling and cooling refrigerant is circulated. In addition,
The cold refrigerant refers to a refrigerant for transporting the cold generated by the Stirling refrigerator 3 to cold utilization equipment 8 such as a freezer.

Both ends of the cold refrigerant line 5 are connected to an inlet plug 6 and an outlet plug 7 fixed to the case 2, and the inlet plug 6 and the outlet plug 7 are connected to outlets of the cold refrigerant pipe of the cold heat utilization equipment 8. The end 9 and the inlet end 10 are each detachably connected.

In the middle of the cold refrigerant pipe 5, a cold refrigerant pump P 2 is arranged so that the cold refrigerant circulates between the cooling head 4 and the cold heat utilization equipment 8.

In addition to the refrigerator, a refrigerator, a throw-in type cooler, a low-temperature liquid circulator, a low-temperature constant temperature device for various temperature characteristic tests, a constant-temperature bath, a heat shock test device, a freeze dryer, a cold dryer, etc. A cooler or the like is applicable.

A cylinder 12 is formed at the top of the housing in the Stirling refrigerator 3, and a motor chamber 14 and a crank chamber 1 are formed inside the housing by a partition wall 13.
5 is divided.

The motor chamber 14 is provided with a motor 16 capable of normal and reverse rotation, and the crank chamber 15 is provided with a rotary reciprocating conversion mechanism 17 for converting the rotation of the motor 16 into reciprocating motion. .

The opening 18 of the motor chamber 14 and the crank chamber 1
The opening 19 of 5 is closed by lids 20 and 21, respectively, and the inside of the housing is maintained in a semi-sealed state.

In the housing, the partition wall 13 penetrates,
Bearing part 2 of housing wall, partition wall 13 and lids 20 and 21
A crankshaft 23 pivotally supported by 2 is rotatably arranged.

The motor 16 includes a stator 24a, and a rotatable rotor 24 on the inner peripheral side of the stator 24a.
The crankshaft 23 is fixed to the center of the rotor 24b.

The rotary reciprocating conversion mechanism 17 includes the crank chamber 1
5, a crank portion 25 of the crankshaft 23 extending into
Connecting rods 26, 2 connected to the crank part 25
7, constituted by cross guide heads 28, 29 and the like attached to the distal ends of the connecting rods 26, 27, and functioning as driving means of the Stirling refrigerator 3.

The cross guide heads 28, 29 are provided with cross guide liners 30, 3 provided on the inner wall of the cylinder 12.
1 are reciprocally movable.

The crank portion 25 is formed with a phase difference so that the crank 25b moves ahead of the crank 25a when the motor 16 rotates forward. As the phase difference, a phase difference of 90 degrees is generally adopted.

A compression cylinder 32 and an expansion cylinder 33 located slightly above the compression cylinder 32 are arranged above the crank chamber 15. A working gas such as helium, hydrogen, or nitrogen is sealed in the housing including the compression cylinder 32 and the expansion cylinder 33.

The compression cylinder 32 has a compression cylinder block 34 fixed to the housing by bolts or the like. A compression piston 36 provided with a piston ring 35 reciprocates in the space of the compression cylinder block 34,
The upper part (compression chamber) of this space is a high-temperature chamber 37, in which the working gas is compressed to a high temperature.

The compression piston rod 38 has one end fixed to the compression piston 36 and the other end extended through an oil seal 39, and is rotatably connected to the cross guide head 28 by a pin.

Since the sliding direction of the reciprocating compression piston 36 is reversed at the top dead center and the bottom dead center, the speed becomes zero.
The velocity is slow near the top dead center and the bottom dead center, and the amount of change in volume per unit time is also small. At the middle point when moving from the bottom dead center to the top dead center and from the top dead center to the bottom dead center, respectively. The maximum speed is reached, and the amount of change in volume due to the movement of the piston per unit time is also maximized.

On the other hand, the expansion cylinder 33 has an expansion cylinder block 40 fixed by bolts or the like above the compression cylinder 32. An expansion piston 42 provided with a piston ring 35 'in the space of the expansion cylinder block 40. Slides back and forth, and the upper part (expansion chamber) of this space is a low-temperature chamber 41, in which the working gas expands to a low temperature.

One end of an expansion piston rod 43 is fixed to the expansion piston 42, and the other end of the expansion piston rod 43 extends through an oil seal 44 and is connected to the cross guide head 29. The expansion piston 42 moves ahead of the compression piston 36 by a phase of 90 degrees.

The expansion cylinder block 40 is provided with a manifold 45 through which working gas flows in and out of the compression chamber of the compression cylinder 32 from below the drawing.
Further, the heat exchanger 46 for heat radiation, the animal cooler 47, and the high temperature chamber 37
Passages 48 are annularly arranged so as to sequentially communicate with each other.

In the vicinity of the upper end of the compression cylinder block 34, a communication hole 4 for communicating the high temperature chamber 37 and the manifold 45 is provided.
Thus, the high-temperature chamber 37 (compression chamber) and the low-temperature chamber 41 (expansion chamber) are connected to the communication hole 49, the manifold 45, the heat-exchanging heat exchanger 46, the animal cooler 47, and the passage 4.
8 so as to sequentially communicate with each other.

The passage 48 may be provided with a heat exchanger at this portion to form a cooler.

The heat-radiating heat exchanger 46 is an annular-type heat exchanger, for example, a shell-and-tube heat exchanger 50 (an operating gas in an annular heat-exchanging chamber 51) as shown in FIGS. (A heat exchanger that cools the working gas by flowing cooling water into the heat exchange chamber 51 by piercing a number of tubes 52 through which heat flows in the axial direction). FIG. 3 is a sectional view taken along the line AA in FIG.

Alternatively, as shown in FIG. 4, an annular jacket 53 may be provided around the annular working gas flow path, and cooling water may flow through the jacket 53 to cool the working gas. .

The heat-exchanging heat exchanger 46 is connected to the cooling water pipe 5
The cooling water is circulated by being connected to the radiator 55 via the cooling water pump 4 and the cooling water pump P1, and the cooling water heated by heat exchange in the heat radiating heat exchanger 46 is cooled by the cooling fan of the radiator 55. .

The cooling water pump P1 is provided with a radiator 55
Is provided in a cooling water pipe 54 that connects the lower end K1 of the heat exchanger 46 and the lower end K4 of the heat exchanger 46 for heat radiation.

As a result, the cooling water pipe 5
Even if air enters the pump, the air is supplied to the cooling water pump P1.
Of the cooling water pump P1 can be suppressed.

At this time, the inlet K2 of the cooling water pump P1
Is provided at a position appropriately lower than K1, the outlet K3 of the cooling water pump P1 is provided at a position appropriately lower than K4, and
If K1 is provided to be lower than K4, air can be substantially prevented from entering the cooling water pump P1, so that the cooling water pump P1 can surely suppress the air bite. it can.

The cooling water pipe 54 is branched and connected to a pipe, and a water reservoir tank 57 is connected to the pipe via a reservoir valve 56.

The radiator 55 is connected to an air vent 58 and a drain valve 59.

The cooling head 4 is formed above the expansion cylinder block 40. For example, as shown in FIGS. 5 and 6, the cooling head 4 is provided with a top wall 62 having a large thickness at the top of the expansion cylinder block 40, and a heat exchange channel 63 for a cryogen is formed on the top wall 62. Configuration.

Alternatively, as shown in FIG. 4, a structure may be adopted in which a jacket wall 64 is provided on the top of the expansion cylinder block 40, and a cooling / cooling refrigerant flows through the jacket wall 64.

As described above, the cooling head 4 is connected to the cold heat utilization device 8 via the cold refrigerant pipe 5 and the cold refrigerant pump P2, and circulates the cold refrigerant. A suction tank 65 is arranged in the cold refrigerant line 5.

A cryogenic refrigerant reservoir tank 67 is connected to the suction tank 65 via a reservoir valve 66. A drain valve 68 is connected to the suction tank 65. Also, in the cold / hot refrigerant line 5,
An air vent 69 is connected.

As the cold refrigerant, ethyl alcohol, HFE, PFC, nitrogen, helium and the like are used.

Next, the operation of the Stirling cooling device 1 of the above embodiment of the present invention will be described. The motor 16 rotates the crankshaft 23 in the forward direction, and the cranks 25a and 25b in the crank chamber 15 rotate with a phase shift of 90 degrees.

Via connecting rods 26, 27 rotatably connected to the crank portions 25a, 25b, cross guide heads 28, 29 attached to the tips of the connecting rods 26, 27 are connected to cross guide liners 30, 31. Slides back and forth inside.

A compression piston 36 and an expansion piston 42 connected to the cross guide heads 28 and 29 via a compression piston rod 38 and an expansion piston rod 43, respectively.
Reciprocate with a phase difference of 90 degrees from each other.

While the expansion piston 42 moves slowly near the top dead center 90 degrees ahead of it, the compression piston 36 moves rapidly toward the top dead center near the middle to perform the compression operation of the working gas. The compressed working gas flows into the heat radiation heat exchanger 46 through the communication hole 49 and the manifold 45.

The working gas radiated to the cooling water in the heat radiating heat exchanger 46 is cooled by the storage cooler 47 and flows into the low temperature chamber 41 (expansion chamber) through the passage 48.

When the compression piston 36 moves slowly near the top dead center, the expansion piston 42 moves rapidly toward the bottom dead center, and the working gas flowing into the low temperature chamber 41 (expansion chamber) expands rapidly. Cold heat is generated.

Thus, the top of the expansion cylinder block 40 in the cooling head 4 surrounding the expansion chamber is cooled to a low temperature.

Then, in the cooling head 4, the cold refrigerant circulating through the cold refrigerant pipe 5 is cooled.

When the expansion piston 42 moves from the bottom dead center to the top dead center, the compression piston 36 moves from the intermediate position to the bottom dead center, and the working gas flows from the expansion chamber through the passage into the animal cooler 47. The cold heat of the working gas is stored in the animal cooler 47.

The cold stored in the animal cooler 47 is reused to cool the working gas sent from the high temperature chamber 37 through the heat radiating heat exchanger 46 again as described above.

Then, the cryogen cooled in the cooling head 4 is supplied from the cryogen line 5 and the outlet plug 7, for example,
It is sent to a cold refrigerant pipe in a cold utilization device 8 such as a freezer,
Freezing or cooling action is performed in the cold heat utilization device 8.

In the cold heat utilization device 8, the cold refrigerant absorbs heat and performs a cooling action, is sent from the cold refrigerant pipe to the inlet plug 6, passes through the cold refrigerant pipe 5, and is returned to the cooling head 4. There it is cooled.

As described above, the cold refrigerant circulates between the cooling head 4 of the Stirling refrigerator 3 and the cold heat utilization device 8,
The cryogenic refrigerant is cooled by the Stirling refrigerator 3, and the cryogenic refrigerant performs a cooling function in the cryogenic heat utilization device 8. Less than,
A similar cycle is repeated.

On the other hand, the cooling water heat-exchanged in the heat radiating heat exchanger 46 flows from the cooling water pipe 54 to the radiator 55, where it is cooled by the cooling fan, and again.
Circulates to

At this time, the cooling water pipe 5
Even if air is stored in the cooling water pump 4, the cooling water pump P1 is provided between the lower end portion K1 of the radiator 55 and the lower end portion K4 of the heat radiating heat exchanger 46. , And the cooling water can be circulated to the heat exchanger 46 for heat radiation stably. Therefore, it is possible to prevent the efficiency of the Stirling cooling device from decreasing.

Next, the defrosting action of the frost generated in the cold heat exchanger of the cold heat utilizing equipment 8 will be described. When defrosting is performed, frost formation is detected by a frost formation sensor (not shown) provided in the cold heat utilization device 8, and the motor 16 of the Stirling refrigerator 3 is rotated in the reverse direction.

As a result, the compression piston 36 and the expansion piston 42 have a phase difference of 90 degrees, and the compression piston 36 acts as an expansion piston and the expansion piston 42 To act as.

Therefore, the working gas in the expansion chamber of the expansion cylinder 33 is compressed by the expansion piston 42 and becomes high in temperature, so that the cold refrigerant is heated by circulating through the cooling head 4 and supplied to the cold heat utilization equipment 8. The frost generated in the heat exchanger of the heat utilization device 8 can be removed.

Therefore, defrosting can be effectively performed even with the cold heat utilization equipment 8 in which the heat exchanger is not provided with defrosting means such as a heater wire.

When the cold heat utilizing device 8 is a cooling constant temperature bath, the cooling operation by the reverse rotation of the motor 16 can be used.

That is, the temperature of the thermostatic chamber is measured while performing the normal cooling operation of the Stirling cooling device of the present invention, and based on the result, the reverse rotation control of the motor 16 is sequentially performed by the temperature control circuit of the temperature control device. Heating operation to maintain a constant temperature.

Although the two-piston type Stirling refrigerator 3 is used in the above embodiment, it is needless to say that another type of Stirling refrigerator 3 such as a displacer type may be used.

[0070]

As described above, the heat exchanger for heat radiation,
A radiator and a pump for cooling water are provided so as to form a circulation path.
In addition, the cooling water pump is provided in the middle of the cooling water pipe connecting the lower end of the radiator and the lower end of the heat exchanger for heat radiation provided at a position higher than the lower end of the radiator. Accordingly, even if air is stored in the cooling water pipe, the cooling water pump can be prevented from being caught by air.

[Brief description of the drawings]

FIG. 1 is an overall conceptual diagram of a Stirling cooling device applied to an embodiment of the present invention.

FIG. 2 is a plan view illustrating an example of a heat radiation heat exchanger.

FIG. 3 is a sectional view taken along the line AA in FIG. 2;

FIG. 4 is a side sectional view illustrating another example of the cooling head of the Stirling cooling device.

FIG. 5 is a side sectional view illustrating an example of a cooling head of the Stirling cooling device.

FIG. 6 is a sectional view showing the cooling head of FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Stirling cooling device 3 Stirling refrigerator 36 Compression piston 37 High temperature chamber (compression chamber) 41 Low temperature chamber (expansion chamber) 42 Expansion piston 46 Heat dissipation heat exchanger 54 Cooling water pipe 55 Heat sink P1 Cooling water pump K1 Heat sink Lower end K2 Inlet of cooling water pump K3 Outlet of cooling water pump K4 Lower end of heat exchanger for heat radiation

Claims (1)

[Claims] A compression piston for compressing the working gas in the compression chamber; an expansion piston for reciprocating out of phase with the compression piston by approximately 90 to expand the working gas in the expansion chamber;
In a Stirling cooling apparatus having a gas flow path connecting the compression chamber and the expansion chamber and connecting a working gas to and fro between them, the Stirling cooling apparatus is provided in the gas flow path, A radiator heat exchanger for exchanging heat between the working gas, which has been compressed in the chamber and the temperature of which has risen, and cooling water; a radiator for radiating heat of the cooling water exchanged by the radiator heat exchanger; The cooling water pipe is provided in the middle of a cooling water pipe connecting a lower end portion and a lower end portion of the heat radiating heat exchanger provided at a position higher than a lower end portion of the heat radiator. A Stirling cooling device, comprising: a cooling water pump for pumping and circulating cooling water.