JP2871183B2 - Cryogenic refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic refrigerator, and more particularly, to a compression unit having a compressor, a cryogenic expander, and switching between supply of high-pressure gas and discharge of low-pressure gas to the expander. The present invention relates to a cryogenic refrigerator provided with a switching valve device for performing the operation.

[0002]

2. Description of the Related Art Conventionally, a cryogenic refrigerator of this kind has been described in, for example, Japanese Patent Application Laid-Open No. 63-148056. This conventional cryogenic refrigerator has a cylinder H having a heat stage G between a high-pressure gas pipe E and a low-pressure gas pipe F extending from a compression unit C having a compressor D, as shown in FIG.
A switching valve device for connecting a cryogenic expander K having a motor base I and a motor housing J, and switching between supplying the high-pressure gas to the cylinder H and discharging the low-pressure gas to the cryogenic expander K. L, and an oil separator M for separating and removing the lubricating oil for the compressor from the high-pressure gas compressed by the compressor D to the high-pressure gas pipe E of the compression unit C.
And an adsorber N for adsorbing and removing impurities in the high-pressure gas that has passed through the oil separator M. The low-pressure gas pipe F of the compression unit C is provided with a pressure of the low-pressure gas sucked into the compressor D. A surge bottle P for reducing fluctuation is provided.

In a cryogenic refrigerator, the pressure fluctuation of the high pressure gas generated when the switching valve device L is switched to the gas supply side and the gas discharge side is controlled by the oil separator M and the adsorber N, Is reduced by the surge bottle P.

[0004]

However, since the cryogenic expander K in the cryogenic refrigerator is usually disposed at a position away from the compression unit C by several meters to several tens of meters, When only the oil separator M, the adsorber N, and the surge bottle P are provided in the compression unit C as in the example, the pressure fluctuation of the high-pressure gas on the compression unit C side can be reduced by the oil separator M and the adsorber N. and the pressure fluctuations of the low pressure gas is to be reduced by the surge bottle P, the pressure fluctuation P of the pressure fluctuation P ₃ and the low pressure gas of the high pressure gas as with a cryogenic expander K side indicated by a chain line in FIG. 3
₄ cannot be reduced much, and the pressure fluctuation of the high-pressure gas and the low-pressure gas is large. For this reason, the gas supply / discharge efficiency of the expander A decreases, the operating differential pressure ΔP ₂ on the expander K side increases, and the refrigeration capacity in proportion to the operating differential pressure ΔP ₂ decreases. There is.
Incidentally, in order to reduce the pressure fluctuation of the high-pressure gas and the low-pressure gas on the expander K side, it is possible to increase the volume of the oil separator M, the adsorber N and the surge bottle P provided in the compression unit C to a certain extent. Although the effect can be expected, not only the pressure fluctuation cannot be reduced significantly, but also the overall size becomes large and the cost increases, and the above problem cannot be solved.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to provide a compressor having a volume portion for absorbing pressure fluctuations even when a cryogenic expander is arranged at a position far away from a compression unit. An advantage of the present invention is that the gas exhaust efficiency on the expander side can be increased without increasing the volume, and the refrigeration capacity can be improved.

[0006]

According to the present invention, a compression unit A having a compressor 1 is provided.
In a cryogenic refrigerator including a cryogenic expander B and a switching valve device 9 for switching between supply of a high-pressure gas and discharge of a low-pressure gas to the expander B, A high-pressure gas passage 13 extending from the switching valve device 9 to the compressor 1 and a low-pressure gas passage 12 at least in the low-pressure gas passage 12 near the outlet of the switching valve device 9 for absorbing a pressure fluctuation. Was provided.

A high-pressure volume section 16 for absorbing pressure fluctuation and a low-pressure volume are provided near the inlet of the switching valve device 9 in the high-pressure gas passage 13 and near the outlet of the switching valve device 9 in the low-pressure gas passage 12. It is preferable to provide each of the parts 14.

The cryogenic expander B has a heat stage 4
1, a motor base 5 and a motor housing 6, and a supply / discharge passage 81 for supplying high-pressure gas and discharging low-pressure gas to the motor base 5 by switching a switching valve device 9. A block 8 is provided, and a discharge passage 82 communicating with the supply / discharge passage 81 via the switching valve device 9 and a low-pressure volume 14 communicating with the discharge passage 82 are provided. The low pressure gas passage 12 may be connected to 14.

The cryogenic expander B includes a cylinder 4 having a heat stage 41, a motor base 5 and a motor housing 6.
A motor 11 for driving the switching valve device 9 is provided inside,
It is preferable to provide a high pressure volume 16 between the motor shell 15 covering the motor 11 and the motor housing 6, and to connect the high pressure gas passage 13 to the high pressure volume 16.

[0010]

Since the volume portion is provided near the outlet of the switching valve device in the low pressure gas passage, the switching valve device is switched, and when the expansion space of the expander is opened and closed with respect to the low pressure gas passage, the low pressure gas is released. However, at this time, since the volume 14 communicates with the inlet side of the switching valve device 9, that is, the primary side communicating with the expansion space, the low-pressure gas on the expander B side is reduced. pressure fluctuations of a as it can decrease the P ₂ indicated by the solid line to the conventional pressure fluctuation P ₄ indicated by a dotted line in FIG. 3, it can increase the exhaust efficiency of the low-pressure gas. In addition, as a result of the reduced pressure fluctuation, as shown by the solid line in FIG.
P ₁ can be made larger than the operating differential pressure ΔP ₂ indicated by the dotted line, and the refrigeration capacity proportional to the operating differential pressure ΔP ₁ can be improved. Further, the pressure fluctuation of the low-pressure gas not only on the expander B side but also on the compression unit A side is reduced, so that the reliability of the compressor 1 can be improved. Moreover, by providing the volume section 14 on the expander B side as described above, even when the expander B is arranged at a position far away from the compression unit A, the volume section is provided only on the compression unit A side. Since the operating differential pressure ΔP ₁ can be increased as compared with the conventional example, and the refrigerating capacity can be improved accordingly, when the refrigerating capacity is the same, the volume is smaller than when a volume is provided on the compression unit A side. The volume of the unit can be reduced, the space occupied by the refrigerator can be narrowed accordingly, and the space can be saved.

Further, by providing a high-pressure volume 16 near the inlet of the switching valve device 9 in the high-pressure gas passage 13 and providing a low-pressure volume 14 near the outlet of the switching valve device 9 in the low-pressure gas passage 12, Since high-pressure and low-pressure fluctuations on the expander B side can be reduced and gas supply / exhaust efficiency can be increased, the refrigeration capacity can be further improved.

A cylinder 4 having a heat stage 41
And a supply / discharge passage 81 for supplying high-pressure gas and discharging low-pressure gas by switching the switching valve device 9 to the motor base 5 of the cryogenic expander B including the motor base 5 and the motor housing 6. And a discharge block 82 communicating with the supply / discharge passage 81 via the switching valve device 9 and a low-pressure volume section 14 communicating with the discharge passage 82. By connecting the low pressure gas passage 12 to the volume 14, the volume 14 can be brought closer to the supply / discharge passage 81, so that pressure fluctuations can be reduced effectively, and the low pressure gas can be reduced without using a special container. Since the storage volume 14 can be formed, the cost can be reduced.

A motor 11 for driving the switching valve device 9 is provided in the motor housing 6 of the cryogenic expander B, and a high-pressure motor is provided between the motor housing 15 covering the motor 11 and the motor housing 6. A volume 16 is provided,
By connecting the high-pressure gas passage 13 to the high-pressure volume 16, pressure fluctuations of the high-pressure gas and the low-pressure gas can be reduced, and since the volume 16 can be brought close to the supply / discharge passage 81, the pressure fluctuation of the high-pressure gas can be reduced. Can be effectively reduced, and the high-pressure capacity section 16 can be formed without using a special container, so that the cost can be reduced.

[0014]

In FIG. 1, A is a compression unit having a compressor 1, and B is a cryogenic expander connected to the compression unit A via a high-pressure gas pipe 2 and a low-pressure gas pipe 3.

The expander B includes a cylinder 4 having a heat stage 41 at a lower end, a motor base 5 connected to an upper end of the cylinder 4 and having a connection port 51 for the low-pressure gas pipe 3. A motor housing 6 attached to the motor base 5 and having a connection port 61 for the high-pressure gas pipe 2 is provided. The cylinder 4 is reciprocated by introducing high-pressure gas into the cylinder 4 and discharging low-pressure gas. The displacer 7 provided with the cooler 71 therein is reciprocally movable inside, and the lower end of the displacer 7 is exposed to the expansion space 10.
A passage block 8 having a supply / discharge passage 81 communicating with the cylinders 1 and 61 for introducing a high-pressure gas and discharging the low-pressure gas to / from the cylinder 4; And a switching valve device 9 having a valve element 91 for switching between discharge and discharge from the supply / discharge passage 81.
The motor housing 6 contains a motor 92 for driving the valve element 91. The valve body 91 is provided with a high-pressure port for supplying high-pressure gas to the supply / discharge passage 81 and a low-pressure port for discharging low-pressure gas from the supply / discharge passage 81.

The supply / discharge passage 81 of the passage block 8 penetrates in the axial direction from a valve seat surface in contact with the valve body 91 and opens at an upper portion of the cylinder 4. The passage block 8 is provided with a discharge passage 82 extending in the axial direction from the valve seat surface and having a distal end bent in the radial direction to communicate with the connection port 51. A passage leading to the switching valve device 9 via the pipe 3 and the discharge passage 82 is defined as a low-pressure gas passage 12, and the switching valve is provided from the compressor 1 through a space in the high-pressure gas pipe 2, the motor base 5 and the motor housing 6. The passage leading to the device 9 is a high-pressure gas passage 13.

The motor base 5 is provided with a low-pressure volume section 14 having a substantially semi-cylindrical cross section in which the discharge passage 82 and the connection port 51 communicate with each other. The low-pressure gas pipe 3 is connected to the motor housing 6 via a motor shell 15 and the inner surface of the motor housing 6. The high-pressure capacity section 16 is provided with the connection port 61.
The high-pressure gas pipe 2 is connected via the.

A slack piston 17 interlocking with the displacer 7 through a predetermined stroke is provided between the displacer 7 and the passage block 8 in the cylinder 4 so as to freely reciprocate. The supply / discharge passage 81 is provided at a position facing the low-pressure capacity portion 14 via a capillary tube.
To the low-pressure gas passage 12 via a bleed.
The surge volume 18 is connected to the counter chamber 21 at an intermediate pressure through the orifice 19 to the opposing chamber 21 facing the working chamber 20 of the slack piston 17. When the high-pressure gas is introduced into the cylinder 4 from the supply / discharge passage 81 by the switching valve device 9, the pressure difference between the high pressure in the cylinder 4 and the intermediate pressure in the opposed chamber 21 causes the displacer 7 to pass through the passage. When the supply / discharge passage 81 communicates with the low-pressure gas passage 12 by the switching valve device 9 and the pressure in the cylinder 4 becomes low, the low pressure in the cylinder 4 and the opposed chamber Due to the pressure difference from the intermediate pressure in 21, the displacer 7 moves back toward the heat stage 41, and the low-pressure gas after expansion is discharged. By repeating the output so as to obtain the extremely low temperature in the heat stage 41.

In FIG. 1, reference numeral 22 denotes a mounting flange fixed to an end of the cylinder 4 on the side of the passage block. The mounting flange 22 is connected to the motor base 5 and the motor housing 6 by connecting bolts. .

The present invention is constructed as described above. As shown in FIG. 1, the displacer 7 is in the home position and the valve 9
When one high pressure port is closed with respect to the supply / discharge passage 81, the high pressure gas passage 13 and the high pressure volume 16 are filled with high pressure gas. When the high pressure port of the valve body 91 is connected to the supply / discharge passage 81 by driving the motor 11 to rotate the high pressure port, as shown by a dotted line in FIG. Until the end, the pressure of the high-pressure gas decreases, and after the high-pressure port has been opened, the pressure rises. However, the high-pressure gas passage 13 has a high-pressure volume near the inlet of the switching valve device 9. 1
3, the high-pressure gas in the high-pressure volume 16 flows from the high-pressure port into the supply / discharge passage 81 from the start of opening of the high-pressure port to the end of opening as shown by the solid line in FIG. Therefore, the pressure drop of the high-pressure gas can be reduced. As a result, the pressure fluctuation P ₁ of the high pressure gas is made smaller as shown by the solid line, compared to the pressure fluctuation P ₃ shown by the dotted line in FIG. 3, it can increase the trapping efficiency of the high pressure gas. Further, when the valve element 91 rotates after the high-pressure port is closed and the low-pressure port of the valve element 91 communicates with the supply / discharge passage 81, the low-pressure port starts opening as shown by the dotted line in FIG. The pressure of the low-pressure gas is increased until the opening is completed, and the pressure is reduced after the opening of the low-pressure port.
2, the low pressure volume 14 near the outlet of the switching valve device 9
Since the low-pressure gas in the low-pressure volume section 14 flows from the low-pressure port into the supply / discharge passage 81 from the start of opening of the low-pressure port to the end of opening as shown by the solid line in FIG. Thus, the pressure rise of the low-pressure gas can be reduced. As a result, the pressure fluctuation P _{2 of the} low-pressure gas
Can be reduced as shown by the solid line as compared with the pressure fluctuation P ₄ shown by the dotted line in FIG. 3, and the exhaust efficiency of the low-pressure gas can be increased. As described above, when the supply / discharge passage 81 is switched from the low-pressure gas passage 12 to the high-pressure gas passage 13 and when the supply / discharge passage 81 is switched from the high-pressure gas passage 13 to the low-pressure gas passage 12, the cylinder 4 communicating with the supply / discharge passage 81 Pressure fluctuations of the high-pressure gas and the low-pressure gas on the side can be reduced, so that the supply / discharge efficiency can be increased, and the expansion device
Conventional operating differential pressure showing the operation differential pressure △ P ₁ at the side by a dotted line △
Can be increased to P _2, it can improve the refrigerating capacity is proportional to the operating differential pressure △ P _1. As described above, the high-pressure volume section 16 and the low-pressure volume section 14 are located on the cryogenic expander B side.
In this case, the operating differential pressure ΔP ₁ can be increased as compared with the conventional example in which a surge bottle is provided on the compression unit A side. Thus, the volume of the volume can be reduced as compared with the case where a refrigerator or the like is provided, and the space occupied by the refrigerator can be narrowed accordingly, and the space can be saved.

In the embodiment described above, the low-pressure volume section 14 is provided in the motor base 5 and the high-pressure volume section 16 is provided in the motor housing 6. However, as shown in FIG. And the low-pressure gas pipe 3 may be provided on the cryogenic expander B side. Each of the volume portions 14 and 16 in FIG. 4 is obtained by attaching a pressure vessel to the high-pressure gas pipe 2 and the low-pressure gas pipe 3, but instead of providing a pressure vessel, a high-pressure gas pipe is provided as shown in FIG. 2 and the low-pressure gas pipe 3 may be formed in a stepped structure having a large-diameter portion, and the large-diameter portions may be used as the volume portions 14 and 16. When the low-pressure capacity section 14 is provided on the motor base 5, the low-pressure capacity section is formed in a substantially C-shaped cross section as shown in FIGS. 18 may be formed in a substantially C shape. Further, each of the volume portions 14 and 16 may be any one of the structure shown in FIG. 1, 2 or FIGS. 6 and 7 and the structure shown in FIG. 4 or FIG.

In the above embodiment, the low-pressure volume 1
4 and the high-pressure volume 16 are provided, but the other high-pressure volume 16 may be eliminated and only the low-pressure volume 14 may be provided. However, the high pressure volume 16 and the low pressure volume 1
4, the operating differential pressure ΔP ₁ can be increased,
It is preferable to provide both in terms of further improving the refrigerating capacity.

[0023]

As described above, the present invention provides a compression unit A having a compressor 1, a cryogenic expander B, and the expander B.
And a switching valve device 9 for switching between supply of high-pressure gas and discharge of low-pressure gas, the high-pressure gas passage 13 extending from the compressor 1 to the switching valve device 9.
And the low-pressure gas passage 12 from the switching valve device 9 to the compressor 1 is provided with a volume portion 14 for absorbing pressure fluctuation at least in the low-pressure gas passage 12 near the outlet of the switching valve device 9. When the valve device 9 is switched and the expansion space of the expander is opened and closed with respect to the low-pressure gas passage 12, a pressure fluctuation occurs in the low-pressure gas. Side, ie
Since will be in communication with the primary side leading to the expansion space, the pressure fluctuations of the low pressure gas in the expander B side can decrease over conventional pressure fluctuation P ₄ indicated by a dotted line in FIG. 3 to P ₂ indicated by a solid line Therefore, the exhaust efficiency of the low-pressure gas can be increased. Moreover, as a result of the reduced pressure fluctuation, the operating differential pressure ΔP ₁ on the expander B side can be made larger than the conventional operating differential pressure ΔP ₂ indicated by the dotted line as shown by the solid line in FIG.
The refrigeration capacity proportional to the operating pressure difference ΔP ₁ can be improved. Further, the pressure fluctuation of the low-pressure gas not only on the expander B side but also on the compression unit A side is reduced, so that the reliability of the compressor 1 can be improved. Moreover, by providing the volume section 14 on the expander B side as described above, even when the expander B is arranged at a position far away from the compression unit A, the volume section is provided only on the compression unit A side. Since the operating differential pressure ΔP ₁ can be increased as compared with the conventional example, and the refrigerating capacity can be improved accordingly, when the refrigerating capacity is the same, the volume is smaller than when a volume is provided on the compression unit A side. The volume of the unit can be reduced, the space occupied by the refrigerator can be narrowed accordingly, and the space can be saved.

Further, by providing a high-pressure volume 16 near the inlet of the switching valve device 9 in the high-pressure gas passage 13 and providing a low-pressure volume 14 near the outlet of the switching valve device 9 in the low-pressure gas passage 12, Since the high and low pressure fluctuations on the expander B side can be reduced and the gas supply / exhaust efficiency can be increased, the operating differential pressure ΔP ₁ can be further increased, and the refrigeration capacity can be further improved.

A cylinder 4 having a heat stage 41
And a supply / discharge passage 81 for supplying high-pressure gas and discharging low-pressure gas by switching the switching valve device 9 to the motor base 5 of the cryogenic expander B including the motor base 5 and the motor housing 6. And a discharge block 82 communicating with the supply / discharge passage 81 via the switching valve device 9 and a low-pressure volume section 14 communicating with the discharge passage 82. By connecting the low pressure gas passage 12 to the volume 14, the volume 14 can be brought closer to the supply / discharge passage 81, so that pressure fluctuations can be reduced effectively, and the low pressure gas can be reduced without using a special container. Since the storage volume 14 can be formed, the cost can be reduced.

A high-pressure chamber 16 is provided between the motor housing 6 and the motor shell 15 for covering the motor 11 in the motor housing 6 of the cryogenic expander B. By connecting the passage 13, the pressure fluctuation of the high-pressure gas and the low-pressure gas can be reduced, and the pressure fluctuation of the high-pressure gas can be effectively reduced because the volume 16 can be brought close to the supply / discharge passage 81. In addition, the high-pressure capacity section 16 can be formed without using a special container, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of only a main part of a cryogenic expander of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is an explanatory diagram showing pressure fluctuations of a high-pressure gas and a low-pressure gas.

FIG. 4 is a partially cutaway view showing an example in which a volume is provided in a gas pipe.

FIG. 5 is a sectional view showing another example in which the same volume is provided in a gas pipe.

FIG. 6 is a sectional view taken along line YY of FIG. 7 showing another embodiment.

FIG. 7 is a plan view taken along the center of FIG. 6;

FIG. 8 is a sectional view of a conventional example.

[Explanation of symbols]

 Reference Signs List A compression unit B cryogenic expander 1 compressor 4 cylinder 5 motor base 6 motor housing 8 passage block 81 supply / discharge passage 9 switching valve device 91 valve body 11 motor 12 low-pressure gas passage 13 high-pressure gas passage 14 low-pressure volume 15 motor Shell 16 High pressure volume

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F25B 9/14 530

Claims (4)

(57) [Claims] A cryogenic expander (B) and a switching valve device (9) for switching between supply of high-pressure gas and discharge of low-pressure gas to the expander (B). In the low-temperature refrigerator, at least in the low-pressure gas passage 12 among the high-pressure gas passage 13 from the compressor 1 to the switching valve device 9 and the low-pressure gas passage 12 from the switching valve device 9 to the compressor 1. A cryogenic refrigerator characterized by comprising a volume section (14) for absorbing pressure fluctuations near an outlet of a switching valve device (9). 2. A high-pressure volume section 16 for absorbing pressure fluctuation is provided near the inlet of the switching valve device 9 in the high-pressure gas passage 13 and near the outlet of the switching valve device 9 in the low-pressure gas passage 12.
And a low-pressure capacity portion (14).
The cryogenic refrigerator described. 3. A cryogenic expander B includes a cylinder 4 having a heat stage 41, a motor base 5 and a motor housing 6, and supplies a high pressure gas to the motor base 5 by switching a switching valve device 9. A passage block 8 having a supply / discharge passage 81 for discharging low-pressure gas is provided, and a discharge passage 82 communicating with the supply / discharge passage 81 via the switching valve device 9 and the discharge passage 82 communicate with each other. A low-pressure gas volume 1 is provided in the low-pressure gas volume 14.
2. The cryogenic refrigerator according to claim 1, wherein the second refrigerator is connected to the second refrigerator. 4. A cryogenic expander B includes a cylinder 4 having a heat stage 41, a motor base 5 and a motor housing 6, and a motor 11 for driving a switching valve device 9 is mounted on the motor housing 6. Together with the motor 1
A high-pressure volume 16 is provided between the motor housing 15 and the motor housing 6 covering the motor shell 1.
4. The cryogenic refrigerator according to claim 2, wherein a high-pressure gas passage is connected to the cryogenic refrigerator.