JPH06313644A - Controlling method for very low temperature refrigerating plant - Google Patents

Abstract

PURPOSE:To prevent shortage of oil in a compressing part of a compressor even when the temperature of outside air falls in a large degree. CONSTITUTION:When the temperature of outside air measured by a temperature sensor 52 lowers to a prescribed temperature or below, a transfer valve 39 is operated so that oil from a compressor 11 may flow through a bypass pipe 38 and bypass an oil heat exchanger 12A, while electric heaters 42 and 43 are electrified to heat the oil flowing through an oil return route 36. Even when the temperature of the outside air falls in a large degree in the winter in a cold district or others, therefore, no shortage of the flow rate of the oil due to an increase in the viscosity thereof takes place and the compressor 11 is always supplied with the oil in a sufficient quantity. Since the compressor is operated in a normal state through a year, a cooling operation in normal conditions is always executed in a vary low temperature cooler 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic refrigeration system for expanding and cooling a pressurized gas body as a cooling medium.

[0002]

2. Description of the Related Art In this type of apparatus, like a cryogenic refrigerating apparatus 500 shown in FIG. 4, a refrigerant body pressurized in a compression section 100, such as helium, is sent to a cryogenic cooling section 200 to perform required cooling. After the operation, it is returned to the compression unit 100, and is circulated such that it is pressurized again and sent to the cryogenic cooling unit 200, and an adjustment unit 300 for smoothly and stably performing various operations in the compression unit 100 is provided. Has become.

More specifically, the compressor 11 pressurizes a predetermined gas body, for example, helium gas, as a refrigerant body, and the second heat exchanger 12B cools the temperature increase due to the compression, and then the oil separator 13 is used. The oil component used for pressurization is diverted, the oil component is returned to the compressor 11 via a path described later, and the cooled refrigerant body is fed to the adsorber 1
Give to 4. The adsorber 14 contains an absorbent such as activated carbon inside, and absorbs and separates a fine oil component that could not be split by the oil separator 13 and sends only the refrigerant body to the outward pipe 21.

The refrigerant body performs a required cooling action through a cryogenic cooler 23 such as a cryopump via a supply valve 22, and then flows into an accumulator 15 via a discharge valve 24 and a return pipe 25. The circulation path of being temporarily stored here and being again pressurized by the compressor 11 is followed.

The heat generated in the mixed fluid of oil and refrigerant at the time of compression in the compressor 11 is cooled in the first heat exchanger 12C.

The adjusting portion 300 is provided with a bypass pipe 31 that bypasses between the oil outlet side of the oil separator 13 and the return pipe 25.
By adjusting the required pressure with the differential pressure valve 32 and the pressure equalizing valve 33 provided in the middle of the path, unnecessary high pressure or the like to the cryogenic cooler 23 or the compressor 11 is bypassed and the cryogenic cooler 23 and the compressor are bypassed. 11, an adjusting operation for preventing abnormal operation, and an adjusting operation for reducing the pressure by providing a pressure reducer 35 including a capillary tube on the bypass pipe 34 for returning the oil component separated by the oil separator 13 to the compressor 11, The oil return path 36 for cooling the oil in the machine 11 by the oil heat exchanger 12A and returning it to the compressor 11 again is provided with a decompressor 37 composed of a capillary tube or the like to perform an adjusting operation for decompressing. is there.

The first heat exchanger 12C is a heat exchanger for cooling the mixed fluid of the refrigerant body and oil as described above, and cools most of the compression heat of the refrigerant body. The second heat exchanger 12B is a heat exchanger mainly for cooling the refrigerant body, and cools the operation part of the compressor 11, for example, the heat generation of the motor part and the heat conduction part of the compression heat. The oil heat exchanger 12A is a heat exchanger mainly for cooling the oil, and cools the oil in the compressor 11 to suppress heat generation in the compression process of the refrigerant body.

The first heat exchanger 12C and the second heat exchanger 12C
The cooling fan 16 is used to blow relatively cool air (outside air) as cooling air to the heat exchanger 12B and the oil heat exchanger 12A to improve heat exchange efficiency.

However, the cryogenic refrigerator 500 having the above-mentioned structure
Is often installed in observatory equipment, such as an observatory, which is built in a high-altitude area where air is clean, and when installed in a cold area at such high latitudes, it is not uncommon to have a freezing point in winter.

Therefore, the cryogenic refrigerating apparatus of the type which cools the oil heat exchanger 12A with water, which is disclosed in Japanese Patent Laid-Open No. 3-217763, cannot be used due to the solidification of the cooling water. Shown oil heat exchanger 1
Even in the cryogenic refrigeration apparatus 500 that air-cools 2A, when the outside air temperature becomes low, the temperature of the oil cooled by the cooling fan 16 falls too much and the viscosity increases, which hinders the oil circulation and causes normal operation. There was a problem that I could not drive.

Therefore, for example, as illustrated in FIG.
An electric heater 41 as a heating means is provided on the outer surface of the compressor 11.
And the temperature sensor 51 is installed,
There is a cryogenic refrigeration system 500D in which the controller 61 controls the energization of the electric heater 41 to prevent the temperature of the compressor 11 from falling below a predetermined temperature (for example, 0 ° C.).

[0012]

However, in the cryogenic refrigerating apparatus 500D having the above-mentioned structure, the oil of the compressor 11, which is heated by the electric heater 41, is cooled by the cooling fan 16 blowing air. The temperature at the outlet of the oil heat exchanger 12A greatly depends on the outside air temperature. Therefore, if the outside air temperature becomes too low, for example, in winter in a cold region, the temperature of the oil in the oil heat exchanger 12A / oil return path 36 becomes too low, the viscosity increases, and the amount of oil circulation becomes insufficient, resulting in compression. In some cases, stable operation of the aircraft 11 could not be continued.

Further, even when the temperature of the outside air has not dropped so much, the operation is stopped for a long time at the time of maintenance, etc., whereby the compressor 11 is stopped.
Since the temperature of the oil heat exchanger 12A / oil return path 36 and the like is lowered, it takes a long time to warm up for restarting, and the oil heat exchanger 12A / oil return path 36 is restarted after restarting. Since the oil temperature is low and a sufficient amount of oil circulation is not ensured until is sufficiently warmed, there is also a problem that the compressor 11 is operated under severe conditions and the life of the device is shortened.
The solution to this point was an issue.

[0014]

In order to solve the above-mentioned problems of the prior art, the present invention comprises a compression section for pressurizing a refrigerant body with an oil interposed, and the refrigerant body pressurized by this compression section is cryogenically cooled. While supplying it to the cooling unit to perform the required cryogenic cooling,
An air-cooled oil heat exchanger for cooling the oil in the compression section and a cooling fan for blowing cooling air to the air-cooled oil heat exchanger are provided, and the pressure is applied from the air-cooled oil heat exchanger. In a cryogenic refrigeration system provided with an oil heating means in the oil return path to the part to be performed, and further provided with a bypass pipe communicating the oil inlet side and the oil outlet side of this air-cooled oil heat exchanger,

As the temperature of the cooling air decreases, the amount of oil flowing through the air-cooled oil heat exchanger to the bypass pipe is increased, and the oil heating means is activated to increase the heating amount. It is a control method of a cryogenic refrigerator characterized by increasing the

When the cooling air falls below a predetermined temperature, all the circulating oil flows through the air-cooled oil heat exchanger to the bypass pipe, and the oil heating means is activated. It is a control method of the cryogenic refrigerating device to

The amount of oil flowing to the bypass pipe is controlled in accordance with a decrease in temperature of the cooling air or the oil return path facing the oil outlet side of the air-cooled oil heat exchanger, and the heating means installation portion is provided. A method for controlling a cryogenic refrigerating apparatus, characterized in that the heating means is started in accordance with a temperature decrease in the oil return path on a more downstream side.

[0018]

When the temperature of the cooling air (outside air) sent by the cooling fan decreases, the amount of oil flowing to the bypass pipe and bypassing the oil heat exchanger increases and the oil heating means starts. The oil flowing through the oil return path is heated. For this reason, it is possible to maintain the oil flowing through the oil return path at a predetermined temperature or higher and prevent the viscosity of the oil from increasing. Therefore, even if the temperature of the outside air drops significantly in the cold season such as in winter. However, there is no concern that the amount of oil circulation will be greatly reduced and normal operation of the device will not be possible.

Claim 2; When the temperature of the cooling air (outside air) sent by the cooling fan falls below a predetermined temperature, the entire amount of the circulating oil flows into the bypass pipe to completely bypass the oil heat exchanger. At the same time, the oil heating means is activated to heat the oil flowing through the oil return path. For this reason, it is possible to maintain the oil flowing through the oil return path at a predetermined temperature or higher and prevent the viscosity of the oil from increasing. Therefore, even if the temperature of the outside air drops significantly in the cold season such as in winter. However, there is no concern that the amount of oil circulation will be greatly reduced and normal operation of the device will not be possible.

Claim 3; When the temperature of the cooling air (outside air) sent by the cooling fan or the temperature of the oil return path facing the oil outlet side of the air-cooled oil heat exchanger decreases, it flows into the bypass pipe to pass through the oil heat exchanger. When the amount of oil that bypasses increases and the temperature of the oil return path on the downstream side of the installation location of the heating means decreases, the heating means is activated and heats the oil, so that the oil flowing through the oil return path is heated to a temperature above a predetermined temperature. It is possible to maintain the viscosity of the oil and prevent the oil from increasing in viscosity, and even if the temperature of the outside air drops significantly in winter in cold regions, the amount of oil circulation greatly decreases and normal operation of the device is prevented. There is no concern that it will not be possible.

[0021]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described in detail with reference to the cryogenic refrigerating apparatus 500A shown in FIG. In this figure, the parts denoted by the same reference numerals as those in FIGS. 4 and 5 are the parts having the same functions as those described in the above drawings, and will be described within the range that does not impair the understanding of the present invention. Omitted.

In FIG. 1, reference numeral 38 is a bypass pipe that connects the oil inlet side and the oil outlet side of the air-cooled oil heat exchanger 12A. Oil discharged from the compressor 11 is supplied to the bypass pipe 38 via a switching valve 39 controlled by the controller 62 when the temperature of the cooling air (outside air) measured by the temperature sensor 52 falls below a predetermined temperature. It flows through the oil heat exchanger 12A by-pass.

Further, based on the temperature data of the outside air measured by the temperature sensor 52, the controller 63 causes the electric heater installed in the pipe portion between the oil heat exchanger 12A of the oil return path 36 and the pressure reducer 37. 42 and decompressor 37
It is provided so as to control the energization of the electric heater 43 installed in the.

That is, the controllers 62 and 63
For example, as illustrated in Table 1, when the temperature T of the outside air measured by the temperature sensor 52 is higher than a predetermined temperature T1 (for example, 0 ° C.), the oil discharged from the compressor 11 flows to the oil heat exchanger 12A. When the outside air temperature T is equal to or lower than the predetermined temperature T1, the oil discharged from the compressor 11 is diverted to the side path. The switching valve 39 is switched on so as to flow to the pipe 38 and bypass the oil heat exchanger 12A, and at the same time, the electric heater 4
The design is such that the heater is switched on so that the electricity is heated by 2.43.

[0025]

[Table 1]

Therefore, in the cryogenic refrigerating apparatus 500A having the controllers 62 and 63 capable of controlling the above, the oil discharged from the compressor 11 when the outside air temperature T measured by the temperature sensor 52 is higher than the predetermined temperature T1. Flows to the oil heat exchanger 12A, where the cooling fan 16
Is effectively cooled by the outside air having a relatively low temperature and there is no electric heating by the heating means 42, 43 of the oil return path 36, so the oil heated during compression in the compressor 11 is sufficiently cooled. In the closed state,

When the outside air temperature T falls below the predetermined temperature T1, the oil flows through the bypass pipe 38 and the oil heat exchanger 12
The oil does not flow to A, and at the same time, electric heating is performed by the heating means 42 and 43 to heat the oil in the oil return path 36. Since the increase in the viscosity of the oil is prevented and the oil circulation amount is secured, a sufficient amount of oil is constantly recirculated to the compressor 11, and the compressor 11
Is always in normal condition regardless of the four seasons.

The controllers 62 and 63 operate the switching valve 39 and the electric heaters 42 and 43 as shown in Table 1, and also, as shown in Tables 2 to 4, the outside air temperature T measured by the temperature sensor 52. Is divided into three or more regions, and the switching valve 39 and the electric heaters 42 and 43 are operated so that the temperature of the oil flowing back to the compressor 11 decreases as the outside air temperature T increases.
The switching valve 39 and the electric heater 4 are arranged so that the temperature of the oil flowing back to the compressor 11 is less likely to decrease as the outside air temperature T is lower.
It is also possible to operate 2.43.

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

(Embodiment 2) Next, a second embodiment of the present invention will be described in detail based on the cryogenic refrigerator 500B shown in FIG. Note that, in this figure, the portions denoted by the same reference numerals as those in FIGS. 1 and 4 and 5 are the portions that have already been described, so the description thereof is omitted within the range that does not impair the understanding of the present invention.

Reference numeral 53 is a temperature sensor that is inserted and installed in the pipe of the oil return path 36 facing the outlet of the oil heat exchanger 12A and directly measures the temperature of the oil flowing in the pipe. Reference numeral 54 is the oil Return pipe 25 of return path 36
It is a temperature sensor that is inserted and installed in the pipe of the part that faces the, and directly measures the temperature of the oil flowing in the pipe.

Then, in this case, the controller 62 controls the switching of the switching valve 39 based on the oil temperature data measured by the temperature sensor 53, and the controller 63 electrothermally operates based on the oil temperature data measured by the temperature sensor 54. The electric heating by the heaters 42 and 43 is controlled.

That is, the controller 62 switches so that the oil discharged from the compressor 11 flows to the oil heat exchanger 12A when the temperature of the oil downstream of the oil heat exchanger 12A measured by the temperature sensor 53 is higher than a predetermined temperature. Valve 39
When the temperature becomes equal to or lower than the predetermined temperature, the switching valve 39 is operated so as to flow to the bypass pipe 38 and bypass the oil heat exchanger 12A, and the controller 63 joins the return pipe 25 measured by the temperature sensor 54. When the temperature of the oil to be heated is higher than a predetermined temperature, the switch is turned off so that the electric heaters 42 and 43 do not perform the electric heating, and when the temperature becomes lower than the predetermined temperature, the switch is turned on so that the electric heaters 42 and 43 perform the electric heating. It is designed.

Therefore, the cryogenic refrigerator 5 having the above-mentioned structure
In 00B, when the oil temperature measured by the temperature sensor 53 is higher than the predetermined temperature, the oil discharged from the compressor 11 flows to the oil heat exchanger 12A and is effectively cooled there, so that Even if it is heated at the time of compression, it is sufficiently cooled and refluxed in the compressor 11.

On the other hand, when the oil temperature measured by the temperature sensor 53 becomes lower than the predetermined temperature, the oil discharged from the compressor 11 flows to the side heat pipe 38 to the oil heat exchanger 12A in response to a command from the controller 62. When the temperature of the oil measured by the temperature sensor 54 is below the predetermined temperature even if the switching valve 39 is switched so as not to flow and the oil heat exchanger 12A is bypassed, the controller 63 outputs a control signal. Even if the electric heaters 42 and 43 perform energization heating to significantly reduce the outside air temperature, the oil flowing back to the compressor 11 through the oil return path 36 is maintained at a predetermined temperature or higher, Since the increase in viscosity is prevented and the oil circulation amount is secured, a sufficient amount of oil always flows back to the compressor 11, and the compressor 11 is always operated in a normal state. That.

Also in this case, regarding the switching operation of the switching valve 39 and the electric heating operation of the electric heaters 42 and 43,
As shown in Tables 2 to 4, the multi-stage control can be performed depending on the oil temperature levels measured by the temperature sensors 53 and 54.

Regarding the temperature sensors 53 and 54,
The temperature of the oil flowing inside the pipe is directly measured by inserting and installing it in the pipe of the oil return path 36, and the temperature of the oil flowing inside the pipe is measured by being installed outside the pipe. Alternatively, the temperature of the oil flowing in the pipe may be measured by embedding it in the pipe wall.

(Embodiment 3) Next, a cryogenic refrigerating apparatus 500C according to a third embodiment of the present invention will be described in detail with reference to FIG. Note that, in this figure, the portions denoted by the same reference numerals as those in FIGS. 1 and 2 and FIGS. 4 and 5 are the portions that have already been described, so description thereof is omitted within the range that does not impair the understanding of the present invention. .

In this cryogenic refrigerator 500C,
The controller 62 controls the switching of the switching valve 39 based on the temperature data of the cooling air (outside air) measured by the temperature sensor 52, and the controller 63 controls the electric heater 42, based on the oil temperature data measured by the temperature sensor 54. Four
It is provided so as to control the energization to 3.

That is, the cryogenic refrigerator 50 having the above structure
At 0C, when the temperature of the outside air measured by the temperature sensor 52 is higher than a predetermined temperature, the switching valve 39 is operated so that the oil from the compressor 11 flows to the oil heat exchanger 12A, and the oil measured by the temperature sensor 54 is changed. When the temperature is higher than the predetermined temperature, electric heating by the electric heaters 42 and 43 is not performed, and when the temperature of the outside air measured by the temperature sensor 52 is equal to or lower than the predetermined temperature, it flows into the bypass pipe 38 and the oil heat exchanger 1
Even if the switching valve 39 is operated so as not to flow to 2A and the oil temperature measured by the temperature sensor 54 is equal to or lower than the predetermined temperature even when the oil heat exchanger 12A is bypassed, the electric heaters 42 and 43 are provided.
The energization heating is performed so that the temperature of the oil flowing back to the compressor 11 is maintained at a predetermined temperature.

Therefore, the cryogenic refrigerator 50 having the above structure
Even at 0C, the operation control is such that when the outside air temperature is high, the action of cooling the oil heated in the compression process in the compressor 11 is enhanced, and when the outside air temperature is low, the action of heating the oil is enhanced. It is possible to operate in normal condition regardless of the four seasons.

Also in this case, regarding the switching operation of the switching valve 39 and the electric heating operation of the electric heaters 42 and 43,
As shown in Tables 2 to 4, the multi-stage control can be performed depending on the oil temperature levels measured by the temperature sensors 53 and 54.

By the way, since the present invention is not limited to the above-mentioned embodiment, appropriate modifications can be made without departing from the spirit of the claims, and for example, the oil may be used in place of the switching valve 39. It is also possible to install a valve capable of freely adjusting the ratio of the oil flow rate flowing to the heat exchanger 12A and the oil flow rate flowing to the bypass pipe 38.

Further, this type of valve can be installed at the confluence of the side pipe 38 and the oil return path 36, or can be installed in the middle of the oil return path 36.

[0047]

As described above, the control method of the cryogenic refrigerating apparatus according to the present invention is provided with the compression section for pressurizing the refrigerant body with the interposition of oil, and the refrigerant body pressurized by this compression section is cryogenically cooled. While supplying it to the cooling unit to perform the required cryogenic cooling,
An air-cooled oil heat exchanger for cooling the oil in the compression section and a cooling fan for blowing cooling air to the air-cooled oil heat exchanger are provided, and the pressure is applied from the air-cooled oil heat exchanger. In a cryogenic refrigeration system provided with an oil heating means in the oil return path to the part to be performed, and further provided with a bypass pipe communicating the oil inlet side and the oil outlet side of this air-cooled oil heat exchanger,

A method for controlling a cryogenic refrigerating apparatus, characterized in that the number of rotations of the cooling fan is reduced and the oil heating means is started as the temperature of the cooling air or the oil return path decreases. ,

The amount of oil flowing to the bypass pipe is controlled in accordance with a decrease in the temperature of the oil return path facing the cooling air or the oil outlet side of the air-cooled oil heat exchanger, and the heating means installation portion is provided. Since it is the control method of the cryogenic refrigeration apparatus, which starts the heating means with the temperature decrease of the oil return path on the more downstream side,

Even if the temperature of the outside air decreases, the oil temperature can be maintained at a predetermined temperature or higher, and there is no concern that the viscosity will increase and the oil circulation amount will decrease.

As a result, the compressor can be operated in a normal state even if the outside air temperature drops significantly in winter, etc., and therefore the radio telescope of an astronomical observatory in which a cryogenic refrigerator is installed, for example, in a cold region. Even when it is used as a cooling device for the observation equipment, the refrigeration action can be achieved without any problem, and a remarkable effect is exhibited.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment.

FIG. 2 is a modification of the second embodiment.

FIG. 3 is a modification of the third embodiment.

FIG. 4 is a block diagram showing the overall configuration of a cryogenic refrigerator.

FIG. 5 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

11 Compressor 12A Oil Heat Exchanger 12B Second Heat Exchanger 12C First Heat Exchanger 13 Oil Separator 14 Adsorber 16 Cooling Fan 21 Outgoing Pipe 23 Cryogenic Cooler 25 Return Pipe 36 Oil Return Path 37 Pressure Reducer 38 Side Pipe 39 Switching valve 41/42/43 Electric heater 51/52/53/54 Temperature sensor 61/62/63 Controller 100 Compression unit 200 Cryogenic cooling unit 300 Adjustment unit 500 / 500A / 500B / 500C / 500D Cryogenic refrigerator

Claims (3)

[Claims] 1. A compression unit for pressurizing a refrigerant body with oil interposed, the refrigerant body pressurized by this compression unit is supplied to a cryogenic cooling unit to perform required cryogenic cooling, and the compressor unit is also provided. An air-cooled oil heat exchanger for cooling oil and a cooling fan for blowing cooling air to the air-cooled oil heat exchanger are provided, and the air-cooled oil heat exchanger is provided with a portion for performing the pressurization. In the cryogenic refrigeration system, in which an oil heating means is provided in the oil return path leading to the oil cooling path, and a bypass pipe is provided to connect the oil inlet side and the oil outlet side of the air-cooled oil heat exchanger, the temperature of the cooling air is lowered. Accordingly, the amount of oil flowing to the bypass pipe by bypassing the air-cooled oil heat exchanger is increased, and the oil heating means is activated to increase the heating amount. Device control method. 2. A compression section for pressurizing a refrigerant body with oil interposed, and the refrigerant body pressurized by this compression section is supplied to a cryogenic cooling section to perform required cryogenic cooling, and at the same time, the compression section is provided. An air-cooled oil heat exchanger for cooling oil and a cooling fan for blowing cooling air to the air-cooled oil heat exchanger are provided, and the air-cooled oil heat exchanger is provided with a portion for performing the pressurization. In the cryogenic refrigeration system, in which an oil heating means is provided in the oil return path leading to the oil cooling path, and a bypass pipe for communicating the oil inlet side and the oil outlet side of the air-cooled oil heat exchanger is provided, the cooling air is cooled to a predetermined temperature. A control method for a cryogenic refrigeration system, characterized in that, when the temperature falls below, all the circulating oil is bypassed through the air-cooled oil heat exchanger to flow into the bypass pipe, and the oil heating means is activated. 3. A compression unit for pressurizing a refrigerant body with oil interposed, the refrigerant body pressurized by this compression unit is supplied to a cryogenic cooling unit to perform required cryogenic cooling, and the compressor unit An air-cooled oil heat exchanger for cooling oil and a cooling fan for blowing cooling air to the air-cooled oil heat exchanger are provided, and the air-cooled oil heat exchanger is provided with a portion for performing the pressurization. In the cryogenic refrigerating device having an oil heating means in the oil return path to the oil cooling path, and a bypass pipe connecting the oil inlet side and the oil outlet side of the air cooling type oil heat exchanger, the cooling air or the air cooling Type oil heat exchanger, the amount of oil flowing through the bypass pipe is controlled as the temperature of the oil return path facing the oil outlet side decreases, and the temperature of the oil return path downstream of the installation portion of the heating means is controlled. With the decline A method for controlling a cryogenic refrigerating apparatus, comprising: