JP2994862B2 - Cryogenic refrigeration equipment - 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 refrigeration system which uses a pressurized gas as a cooling medium and performs control in accordance with the load state of an expansion cooler.

[0002]

2. Description of the Related Art As a cryogenic refrigeration apparatus 500 shown in FIG. 4, a refrigerant compressor 10 driven by an electric motor 10A pressurizes a predetermined gas, for example, helium gas as a refrigerant. The compression unit 100 supplies the high-pressure refrigerant to the outward pipe 21, collects the low-pressure refrigerant that has achieved the required cryogenic cooling from the return pipe 25, and pressurizes it again to supply it to the outward pipe 21. The obtained pressurized refrigerant is supplied to the cryogenic cooler 23 through the supply valve 22, and the cryogenic cooling unit that performs the required cryogenic cooling and returns the low-pressure refrigerant to the return pipe 25 through the discharge valve 24. 200 and outbound pipe 2
The cryogenic cooler 23 or the refrigerant compressor 10 is provided by applying a required pressure adjustment to a bypass valve 32 that operates at a differential pressure provided in the middle of a bypass pipe 31 that bypasses between the return pipe 1 and the return pipe 25.
(Hereinafter referred to as a first conventional technique) provided with an adjustment unit 300 that performs an operation adjustment operation such as preventing unnecessary operation of the cryogenic cooler 23 and the refrigerant compressor 10 by bypassing unnecessary high pressure or the like to the air conditioner. ) Is well known.

[0003] The cryogenic cooler 23 is connected to an electric motor 23A.
The opening and closing operation of the supply valve 22 and the discharge valve 25 is performed in association with an expansion cooling operation in which the pressurized refrigerant is expanded by a displacer that reciprocates in a predetermined cylinder, and cools at an extremely low temperature by an endothermic effect during expansion. Such a configuration (hereinafter, referred to as a second prior art) is disclosed in Japanese Patent Application Laid-Open No. 3-158661 or the like. A cryopump having such a configuration as a part of components is, for example, a cryopump. is there.

In the first prior art, the bypass valve 3
2 generally uses a simple differential pressure valve configured to open when the difference between the pressure on the inlet side and the pressure on the outlet side exceeds a specified value. Depending on operating conditions such as ambient temperature, stable cooling operation may not be performed.
The bypass valve 32 is operated by a differential pressure control circuit 35 for calculating and controlling the pressure difference between the detected pressures by providing pressure detectors 33 and 34 at portions corresponding to the actual compression operation in the compressor section 100. A configuration for controlling (hereinafter, referred to as a third prior art) is disclosed in Japanese Patent Application Laid-Open No. 3-217773.

[0005] More specifically, the configuration of the third prior art described above has a configuration as shown in FIG. In FIG. 5, portions denoted by the same reference numerals as those in FIG. 4 are portions having the same functions as those described with reference to FIG. 4, and each unit operates as follows.

[0006] The refrigerant body pressurized by the compressor 11 cools a temperature rise such as heating by compression in the heat exchanger 12 and then cools.
The oil is supplied to the oil separator 13 to divide the oil used for pressurization. The oil is returned to the compressor 11 via a path (not shown), and the refrigerant is supplied to the adsorber 14. The adsorber 14 absorbs and separates the fine oil that could not be divided by the oil separator, and sends only the refrigerant to the outward pipe 21.

[0007] The cryogenic cooling unit 200 performs a required cooling purpose in the cryogenic cooling unit 200, then discharges it to the return pipe 25, returns to the accumulator 15, temporarily stores the refrigerant, and pressurizes the refrigerant again by the compressor 11. Follow

The bypass valve 31 is connected to the oil separator 1 because the refrigerant returned to the compression section 100 via the bypass pipe 31 does not affect the operation of the adjusting section 30 even if it contains some oil.
It branches off from the outgoing pipe section between 3 and adsorber 14.

As shown in FIG. 5, a differential pressure control circuit 35 is connected to a pressure detector 33 disposed in a line near the accumulator 15 of the return line 25, and to the compressor 11 between the compressor 11 and the heat exchanger 12. The operation is controlled by calculating based on the pressure detected by the pressure detector 34 disposed in the near pipe.

[0010]

In order to start a cryogenic cooler 23, for example, a cryopump or the like in the cryogenic refrigeration apparatus 500, the gas to be exhausted is cooled by a cooling body in the cryogenic cooler 23, for example, It is necessary to cool down to a temperature of 20 K or less to be adsorbed on the cold panel, and the time required for this cooling is called a cool down time.

Since the cryogenic cooler 23 is close to room temperature at the time of starting, the flow rate of the refrigerant flowing through the cryogenic cooler 23 is small, and the flow rate of the refrigerant increases as the cooling progresses. On the other hand, since the compression volume of the compressor 11 and the rotation speed of the electric motor 10A for the compression operation are constant, when the flow rate of the refrigerant is small, the inlet side and the outlet of the compressor 11 are smaller than when the flow rate of the refrigerant is large. The pressure difference with the side becomes large.

When the pressure difference increases, a large load is applied to the compressor 11, and it is erroneously determined that a cause of the failure of the system of the compressor 11 is caused. In the case, the protection device works and the operation stops. For this reason, in the first and second prior arts described above, when the pressure difference becomes equal to or more than a predetermined pressure difference, the bypass valve 32 is opened by the differential pressure control circuit 35 to reduce the pressure difference with respect to the compressor 11 and thereby reduce the predetermined pressure difference. This is to keep it below the value.

However, when the cryogenic cooler 23 is started, the larger the pressure difference, the larger the amount of refrigeration and the more the cooling can be promoted. In contrast, the differential pressure control circuit 35 reduces the pressure difference. Will move in the direction
From the viewpoint of the cryogenic cooler 23, the opposite effect of limiting the promotion of cooling is performed.

For this reason, as shown in FIG.
The variable power supply 27 is used as the power supply to the electric motor 23A that operates the power supply 3 and operates at a high speed when the cryogenic cooler 23 is started, and changes to a low speed as the degree of cooling progresses (hereinafter referred to as a fourth conventional method). Technology)
171359 and the like.

The method of operating the cryogenic cooler 23 at a high speed has disadvantages that the mechanical movement of the cryogenic cooler 23 is apt to cause a failure due to a high speed, and the service life is shortened.

On the other hand, when the ambient temperature is high, the compression section 100 operates under severe conditions, so that an overload protection device such as an overload relay operates, and the cryogenic cooler 23 operates. There is a disadvantage that the operation is interrupted even during the operation.

For this reason, with such a configuration that is free from such inconveniences,
There is a problem that it is desired to provide a cryogenic refrigeration apparatus capable of shortening the cool down time.

[0018]

According to the present invention, a refrigerant pressurized in the above-described compression section is supplied from a forward pipe to a cryogenic cooling section to perform required cryogenic cooling to be discharged to a return pipe. The pressurized refrigerant body that has been reduced in pressure is circulated by pressurizing again in the compression section, and a bypass pipe that bypasses the pipe belonging to the path on the outward pipe side and the pipe belonging to the path on the return pipe side. A variable differential pressure valve means for providing a variable differential pressure valve as the bypass valve, and a forward path of the differential pressure valve. Detects the differential pressure between the pipe side pressure and the return pipe side pressure, detects the cool-down time of the cryogenic cooling unit based on the change in the differential pressure from the start point, and detects the ambient temperature or the compression part temperature Means and the operation of the variable differential pressure valve based on each of the above detections. A configuration is provided in which a control means for controlling the differential pressure to be larger at the time of cool-down than at the time of steady operation and to be reduced in inverse proportion to the ambient temperature or the compression section temperature is provided. Parallel differential pressure valve means in which a first differential pressure valve having a large operating differential pressure and a second differential pressure valve having a predetermined small operating differential pressure are provided in parallel, and information for obtaining information upon cooling down of the cryogenic cooling unit. Means, detecting means for detecting the ambient temperature or the compression section temperature, and based on the above information and detection, select the first differential pressure valve at the time of cooling down, and the ambient temperature or the compression section temperature is lower than a predetermined value. The above problem can be solved by providing a control means for selecting and operating the second differential pressure valve when it is high.

[0019]

When the cryogenic cooler is in the cool-down state, that is, during the cool-down time, the differential pressure regulating valve is bypassed by a large operating differential pressure, so that the pressure difference between the inlet side and the outlet side of the compression unit is reduced. To perform the compression operation, the amount of the refrigerant flowing into the cryogenic cooler increases, which acts to promote the cryogenic cooling.However, when the cryogenic cooler is not at the time of cooling down, that is, In normal operation after the cool-down time elapses and when the ambient temperature is high, the differential pressure regulating valve operates with a small differential pressure. It acts so that cooling is not interrupted during the progress.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIGS.
In these figures, portions indicated by the same reference numerals as those in FIGS. 4 and 5 are portions having the same functions as those described with reference to FIGS. 4 and 5.

[First Embodiment] First, a first embodiment will be described with reference to FIG. The configuration of FIG. 1 includes a differential pressure valve that opens and closes as a bypass valve 32 and is capable of variably adjusting a pressure difference, that is, a variable differential pressure valve unit provided with a variable differential pressure valve 321, a pressure on the outward pipe 21 side of the differential pressure valve 321 and a return pipe. The differential pressure from the pressure on the 25th side is detected by the pressure detector 33 and the pressure detector 34 to detect the cool-down time of the cryogenic cooling unit 200 based on the change in the differential pressure from the starting point, and to detect the ambient temperature at room temperature. Vessel 10
2 and a variable differential pressure valve 321 based on each of the differential pressure detection and the ambient temperature detection.
And control means for providing a control circuit 101 for controlling the operation differential pressure of the cooling circuit to be larger during cool down than during steady operation and smaller in inverse proportion to the ambient temperature.

More specifically, the bypass pipe 31 is a pipe belonging to a path on the outward pipe 21 side, that is, a pipe between the oil separator 13 and the adsorber 14, a pipe belonging to the return pipe 25 side, In other words, the pressure detector 33 is provided so as to bypass the inlet side pipe line of the accumulator 15, and the pressure detector 33 is provided on the forward path pipe 21 side of the variable differential valve 321 provided on the side path pipe 31. Is provided with a pressure detector 34 to each of the pressure values detected and given to the control circuit 101, the difference between the detected values, that is,
By detecting the differential pressure, the cool-down time is detected by utilizing the fact that the differential pressure is large during the cool-down time starting from the start-up and becomes small when the engine enters a steady operation.

The control circuit 101 provides a signal at the time of cooling down based on the above pressure detection and an ambient temperature value near the compression unit 100 detected by the room temperature detector 102, for example, the compression unit 100.
At the time of cool down, the variable differential pressure valve 321 is determined by the temperature value near the slit for sucking the outside air of the casing panel in which the air is sucked or the temperature value of the upper part of the main body of the compressor 11 and the detected differential pressure value. The differential pressure of the variable differential pressure valve 321 is controlled so as to be inversely proportional to the detected temperature value, while the operating differential pressure of the variable differential pressure valve 321 is controlled to be large, that is, to increase the pressure difference for the opening operation.

Therefore, at the time of cooling down, the variable differential pressure valve 321 does not open to a large pressure necessary for forcible pressurization at the time of cooling down, so that the compressor 11 can operate at a large pressure. A large amount of cooling medium will be sent to the section 200, which can promote cryogenic cooling. On the other hand, when the ambient temperature is high, the pressure at which the variable differential pressure valve 321 opens is shifted to the smaller one, so that the compressor 11 can operate at a reasonable pressure, and the overload protection device such as an overload relay operates. There will be no interruption of driving.

[Second Embodiment] Next, a second embodiment will be described with reference to FIG. The configuration shown in FIG. 2 includes, as the bypass valve 32, a parallel differential pressure valve means in which a first differential pressure valve 322 having a predetermined large operating differential pressure and a second differential pressure valve 323 having a predetermined small operating differential pressure are provided in parallel. Information means for obtaining information at the time of cooling down of the cryogenic cooling unit 200 by the control circuit 101A or the like so that a predetermined time from power-on at the time of start-up is set as a cool-down time, and detection of detecting the ambient temperature by the room temperature detector 102. Based on the means and the above information and detection, the first differential pressure valve 322 is selected at the time of cool down, and the second differential pressure valve 323 is selected and operated when the ambient temperature is higher than a predetermined value. And control means for control by the control circuit 101A.

More specifically, the bypass pipe 31 is provided in the same manner as in the first embodiment, and the bypass pipe 31 is provided with a differential pressure valve 322. 323
Are provided in parallel, and the differential pressure valve 322 is adjusted and fixed to a large operating differential pressure suitable for forcible operation of the compression unit at the time of cool down, and the differential pressure valve 322 has an ambient temperature lower than a predetermined value. When it is too high, it is adjusted and fixed to an operating differential pressure at which a protection device such as an overload relay does not operate.

The differential pressure valves 322 and 323 are connected in series with on-off valves 322A and 323A, respectively.
One of the differential pressure valves 322 and 323 is selected by selecting one of A.323A and performing the opening operation.

The control circuit 101A obtains a signal at the time of starting when the power is turned on or the like, and operates a timer circuit from the signal at the time of starting to create a time corresponding to the cool-down time. By selecting the on-off valve 322A as the information to be opened and performing the opening operation, the differential pressure valve 322 is selected, and the passage of the bypass pipe 31 is operated so as to be on the pipe side passing through the differential pressure valve 322.

The room temperature detector 102 detects the temperature in the same manner as in the first embodiment, and when the detected temperature value is higher than a predetermined value, selects the on-off valve 323A to perform the opening operation. To select the differential pressure valve 323 and
It operates so that the first passage is on the side of the pipe passing through the differential pressure valve 323.

Therefore, during cool down, the differential pressure valve 32
2 does not perform the opening operation to a large pressure necessary for forced pressurization at the time of cool down, the compressor 11 can operate at a large pressure, and a large amount of refrigerant is sent to the cryogenic cooling unit 200. And cryogenic cooling can be promoted.

However, when the ambient temperature is high, the differential pressure valve 323 opens with a small pressure even in the case of a cool down, so that the compressor 11 can be operated at a reasonable pressure, such as an overload relay. It does not occur that the overload protection device is operated to interrupt the operation.

Third Embodiment Next, a third embodiment will be described with reference to FIG. The configuration in FIG. 3 includes a bypass valve means that provides a simple on-off valve 324 such as an electromagnetic on-off valve as the bypass valve 32,
A differential pressure detecting means for detecting a differential pressure between the pressure of the on-off pipe 21 side and the pressure of the return pipe 25 side of the on-off valve 324 by the pressure detector 33 and the pressure detector 34, and the cryogenic cooling unit 200 by the start detection circuit 111. Start detecting means for detecting the start of operation of the electric motor 23A of the compressor 10 by the start detecting circuit 112, and detecting means for detecting the ambient temperature by the room temperature detector 102; Based on the start detection, the system detects the cool down time and the steady operation time, selects the small differential pressure value during the steady operation, selects the large differential pressure value at the cool down time, and uses each selected differential pressure value to detect the ambient temperature. Based on the calculated value, the calculated value is calculated to decrease in inverse proportion to the temperature, and the calculated value is compared with the differential pressure value of each pressure obtained by the above-described pressure detection. Those provided with control means providing a control circuit 101B for controlling to open operate the opening and closing valve 324.

Specifically, the bypass pipe 31 and the pressure detector 3
3 and 34 and the room temperature detector 102 are provided in the same manner as in the first embodiment, and the bypass valve 32 is a simple on-off valve 324.

The start detection circuits 111 and 112 drive a compressor 11 of the compressor 100 and a detection signal A for detecting a voltage applied to a motor 23A for driving the cryogenic cooler 23 of the cryogenic cooler 200. A detection signal B that detects the voltage applied to the electric motor 10A is obtained.

The control circuit 101B sets a processing part by the logic circuit and the arithmetic circuit, and sets a large differential pressure reference value C corresponding to a cool down operation and a small differential pressure reference value D corresponding to a steady operation. A part and a timing circuit for timing the time corresponding to the cool down time are provided.

Then, by providing the detection signal A and the detection signal B to a logic circuit to detect whether the system is in a cool down state or a steady operation, a reference value C is selected in the cool down state.
At the time of steady operation, the reference value D is selected, and the selected reference value is calculated by an arithmetic circuit so as to be in inverse proportion to the temperature value E obtained from the room temperature detector 102, thereby generating a calculation reference value F. An arithmetic circuit calculates the differential pressure value G from the detected pressure values of the detectors 33 and 34, and compares the differential pressure value G and the arithmetic reference value F with the arithmetic circuit to calculate the differential pressure value. Only when the value G is larger, the control signal H for opening the on-off valve 324 is obtained, and the cool-down output obtained by the logic circuit is timed by the time-measuring circuit, and the cool-down end signal I The end signal I is determined by a logic circuit, and a reference value D is selected to switch the operation.

Therefore, the on-off valve 324 is connected to the first
By performing substantially the same operation as in the embodiment, the operation can be performed so as to perform the operation of promoting the cryogenic cooling at the time of cooling down and the operation of maintaining the ambient temperature.

[Modification] (1) The side pipe 31 is provided between the forward pipe 21 and the return pipe 25.

(2) The start-up detection circuit 111.1 in the third embodiment is used for the detection at the time of cooling down in the second embodiment.
It is configured to provide a detection signal similar to that in FIG.

(3) Control circuits 101, 101A, 101
B is configured as a control circuit by a microcomputer. When the entire apparatus or a part of the apparatus is controlled by the microcomputer, the control circuits 101, 101A, and 1A are included in the control of the microcomputer.
01B.

(4) In each embodiment, the room temperature detector 10
In place of the temperature detected by the control unit 2, the detected temperature detected by providing a temperature detector at the upper part of the compression unit 100 main body is used as the control unit 10.
The configuration is such that the same temperature control is performed by giving the same to the first, first, and first 101A and 101B.

(5) In the first embodiment, the compression unit 100
, And the detected voltage value is compared with a predetermined reference value. When the detected voltage value is lower and higher than the reference value, the operating differential pressure of the variable differential pressure valve 321 is reduced. Isn't it big when low and small when high? The control circuit 101 is provided with a control function for opening the duct of the bypass pipe 31.

In the second and third embodiments,
Similarly to the above, a control function for opening the duct of the bypass pipe 31 corresponding to the comparison between the voltage value obtained by detecting the power supply voltage and the predetermined reference value is provided in the control circuit 101A.
1B.

(6) In the second embodiment, a third differential pressure valve is additionally provided in parallel as a differential pressure valve, and the operating differential pressure of each differential pressure valve is set to “large”, “medium”, “small”. ), A differential pressure valve with an operating pressure of “large” during cool down, a differential pressure valve with an operating pressure of “small” when the detected temperature is higher than a predetermined value, and “medium” during steady operation. The control circuit 101A is provided with a control function for opening and closing an on-off valve of a pipe passing through the differential pressure valve of the operation differential pressure.

(7) In the second embodiment, similarly to the first embodiment, the open / close valve 322A is provided based on the information obtained by providing the pressure detectors 33 and 34 and judging the cool down time based on the change in the differential pressure detected. Is provided in the control circuit 101A.

(8) In the configuration of (6), the configuration of (7) is provided.

[0047]

According to the present invention, as described above, when the cryogenic cooler is in the operation state at the time of cooling down, the bypass valve bypasses by a large operating differential pressure. The compression operation is performed by increasing the pressure difference between the cryogenic cooler and the outlet side, and the amount of the refrigerant flowing into the cryogenic cooler can be increased, so that the cryogenic cooling can be promoted. When the machine is in a steady operation state other than at the time of cooling down or when the ambient temperature is high, the differential pressure valve operates with a small operating differential pressure, so that the operation of the compression unit becomes unstable, or
There is such a feature that a cryogenic refrigeration apparatus capable of always performing a stable operation can be provided without interrupting cryogenic cooling in the progress of an overload state.

[Brief description of the drawings]

1 to 3 show an embodiment of the present invention, and FIGS.
Shows a conventional configuration, and the contents of each drawing are as follows.

FIG. 1 is a block diagram of a first embodiment.

FIG. 2 is a block diagram of a second embodiment.

FIG. 3 is a block diagram of a third embodiment.

FIG. 4 is a schematic block diagram.

FIG. 5 is a specific block diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Refrigerant compressor 10A Electric motor 11 Compressor 12 Heat exchanger 13 Oil separator 14 Adsorber 15 Accumulator 21 Outgoing pipe 22 Supply valve 23 Cryogenic cooler 23A Electric motor 24 Discharge valve 25 Return pipe 27 Variable frequency power supply 31 Side pipe 32 Valve 33 Pressure detector 34 Pressure detector 35 Differential pressure control circuit 100 Compressor 101 Control circuit 101A Control circuit 101B Control circuit 102 Room temperature detector 111 Start detection circuit 112 Start detection circuit 200 Cryogenic cooling unit 300 Adjustment unit 321 Variable differential pressure valve 322 first differential pressure valve 322A on-off valve 323 second differential pressure valve 323A on-off valve 324 on-off valve 500 cryogenic refrigeration system

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-20754 (JP, A) JP-A-5-113259 (JP, A) JP-A-56-12960 (JP, A) 196054 (JP, U) Japanese Utility Model 2-34963 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F25B 9/00 F25B 9/14 530

Claims (2)

(57) [Claims] 1. A refrigerant body pressurized in a compression section is supplied from a forward pipe to a cryogenic cooling section to perform required cryogenic cooling, and is discharged to a return pipe to reduce the pressure of the refrigerant body to be reduced again. The pressurized and circulated pressure is applied to the side passage valve provided in the side passage pipe that passes between the passage belonging to the forward passage and the passage belonging to the return passage. A cryogenic refrigeration system that performs an opening operation based on a differential pressure, comprising: a variable differential pressure valve means provided with a variable differential pressure valve as the bypass valve; and a pressure on the outward pipe side of the differential pressure valve and the return pipe side. A detecting means for detecting a cool-down time of the cryogenic cooling unit based on a change in the differential pressure from the start point, and detecting an ambient temperature or a compression unit temperature, based on each of the detections. The operating differential pressure of the variable differential pressure valve is During normal operation, make it larger than during normal operation,
A cryogenic refrigeration apparatus comprising: control means for controlling the temperature to be reduced in inverse proportion to the ambient temperature or the compression section temperature. 2. A refrigerant body pressurized in a compression section is supplied from a forward pipe to a cryogenic cooling section to perform required cryogenic cooling, whereby the refrigerant body discharged to a return pipe and reduced in pressure is compressed again. The pressurized and circulated pressure is applied to the side passage valve provided in the side passage pipe that passes between the passage belonging to the forward passage and the passage belonging to the return passage. A cryogenic refrigeration system that opens based on a differential pressure, wherein the bypass valve includes a first differential pressure valve having a predetermined large operating differential pressure and a second differential having a predetermined small operating differential pressure. Parallel differential pressure valve means for providing a pressure valve in parallel, information means for obtaining information at the time of cooling down of the cryogenic cooling unit, detecting means for detecting the ambient temperature or the compression part temperature, based on the information and the detection During the cool down, the first differential pressure valve is selected, Serial cryogenic refrigeration system, characterized by a control means for controlling to operate by selecting the second differential pressure regulating valve when the ambient temperature or compression unit temperature is higher than a predetermined value.