JPH0125976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a cryogenic refrigerator such as a helium refrigerator.

Conventional cryogenic refrigerators are operated by manually controlling the rotational speed of the refrigerator, fluid supply pressure, and extraction of cooling fluid while monitoring the fluid temperature of the refrigerator.

In general, the pistons, cylinders, valves, heat exchangers, piping, etc. of refrigerators are made of various materials and have different coefficients of linear expansion. This is undesirable as it often causes thermal deformation of the body and stiffness of the moving parts. To avoid this, it is necessary for the refrigerator to be operated by a person who is familiar with the refrigerator, which limits the number of operating personnel, and it takes a long time for the refrigerator to drop to the set temperature, making it difficult to secure operating personnel. Have difficulty.

The present invention aims to automate the operation of a refrigerator, thereby eliminating the need for skilled operating personnel and saving labor.

The present invention provides a method for operating a refrigerator in which pressurized fluid is adiabatically expanded and cooled, in which the temperature of the cooling fluid is set to a temperature that does not cause stiffness between constituent members of the refrigerator in the process of lowering the temperature of the refrigerator to a set temperature. a step of detecting the temperature of the fluid that has been adiabatically expanded and cooled by the refrigerator; and a step of detecting the temperature of the fluid that has been adiabatically expanded and cooled by the refrigerator, and the preset cooling that corresponds to the detected temperature of the fluid and the time point at which the temperature is detected. a step of comparing and calculating the temperature of the fluid, a step of determining in advance the relationship between the temperature that does not cause stiffness, the pressure of the fluid that is increased and supplied to the refrigerator, and the rotational speed of the refrigerator; and a step of controlling the fluid pressure and rotational speed to the preset cooling fluid temperature based on the relationship and the comparison calculation result, and the cooling fluid temperature is adjusted to the preset temperature of the refrigerator. This is an attempt to automate driving.

An embodiment of the present invention will be described with reference to the drawings. In FIG. 1, 1 is a reservoir storing fluid at room temperature and high pressure, and 2 is a drive device such as an electric motor that drives a compressor 3. Reference numeral 4 supplies fluid whose pressure has been reduced by a pressure regulating valve to a low pressure circuit 5 which is a fluid supply circuit. 6 is a supply circuit for high pressure fluid discharged from the compressor 3, 7 is a safety valve for the high pressure circuit, 8 is a multistage heat exchanger, and 9 is a cylinder of a reciprocating engine, which also serves as a casing. 10, 11 are pistons, 12 is a suction valve, 13
14 is an exhaust valve, and 14 is a reservoir 1 which lowers the pressure of the cooled high-pressure fluid through a throttle valve and maintains a constant flow rate.
The flow rate and pressure are controlled by the control motor 15. Control motor 1
Reference numeral 5 denotes a step-responsive electric motor that rotates by an amount instructed by an electric panel or the like. 16,1
7 is a shutoff valve for taking in and out cooling fluid from the reservoir 18. 19 is a cold storage tank used for vacuum cold storage. A pin 24 connecting the pistons 10, 11 and the connecting rods 22, 23 is a crankshaft, into which one end of the connecting rods 22, 23 is fitted.
25 and 26 are bearings that support the crankshaft 24. The force generated in the pistons 10 and 11 during adiabatic expansion due to the supply of high-pressure fluid is applied to the connecting rod 2.
2 and 23 to the crankshaft 24.
A pulley 27 is attached to one end of the crankshaft 24 and is connected to a motor generator 30 via a belt 28 and a pulley 29. The motor generator 30 is used as an electric motor when starting the refrigerator, and after starting the refrigerator, it is used as a generator to absorb the power generated by the refrigerator. Reference numerals 31 and 32 denote electric circuits that guide current generated in the motor generator 30 to resistors 33 to 37 when the motor generator 30 is used as a generator. Resistors 33 to 37 are motor generator 30
By increasing or decreasing the electrical resistance values of the resistors 33 to 37, the load on the motor generator 30 is changed to control the rotation speed of the motor generator 30, that is, the rotation speed of the refrigerator. Can be done. 38 is a pressure regulating valve provided in the high pressure circuit 6, and the control motor 3
9 controls the supply pressure.
The control motor 39 is a step response motor that rotates by an amount instructed by electric pulses or the like. Reference numeral 40 designates a temperature sensor for the cooling fluid, and reference numeral 42 designates a rotation speed detector for the motor generator 30, each of which is input to the control device 41 as an electrical analog quantity or an electrical digital quantity. The control device 41 includes an arithmetic processing device 4 including a power supply device 41a, an electronic computer, etc.
1b, an input/output controller 41c that controls the input and output of electric signals, pulse controllers 41d and 41e that send electric pulses to the control motors 15 and 39, and relays 41f to 41 that select the resistors 33 to 37.
It consists of i, etc. 41f' to 41i' are relays 41f to 41i'
41i electrical contact.

FIG. 2 is a characteristic diagram showing the relationship between the fluid temperature of the refrigerator, the operating time, the rotation speed, and the pressure of the high pressure circuit. Optimal characteristics are selected in consideration of thermal deformation of refrigerator components, etc., and these characteristics are programmed and stored in the arithmetic processing unit 41b.

Next, the driving method will be explained. When starting the refrigerator, use a circuit that utilizes only resistor 33,
After the resistor 34, an electric circuit is configured so that each relay contact 41f' to 41i is opened (programmed and stored in the arithmetic processing unit 41b), and after the refrigerator is started, the motor generator 30 starts operating as a generator. Make sure that it does not become a large load when However, if this load immediately after starting is too large, starting will become difficult. Therefore, it is set at an appropriate value. Note that the load resistance of the resistor 33 is necessary to prevent a sudden increase in rotational speed immediately after starting the refrigerator. Another feature of this configuration is that it can perform such startup control. Note that when starting the motor generator 30, a required amount of pulses is output from the arithmetic processing unit 41b to the control motor 39 via the pulse controller 41e so that the adjusted pressure of the pressure control valve 38 becomes the fluid pressure necessary for starting. Conditions are set in the control program of the arithmetic processing unit 41b so that the rotational speed of the refrigerator 42 starts to increase from zero to a constant value and this speed value is input to the arithmetic processing unit 41b, and at the same time, control program to output the required amount of pulses).

The refrigerator is started and the rotation speed of the refrigerator, that is,
After the rotational speed of the motor generator 30 reaches a certain rotational speed, the following control is performed. That is, the temperature of the cooling fluid that is pressurized by the compressor 3, supplied to the refrigerator through the high-pressure circuit 6, and adiabatically expanded and cooled by the reciprocating engine constituting the refrigerator is detected by the temperature detector 40. Ru. The detected temperature is input from the temperature detector 40 to the arithmetic processing unit 41b via the input/output controller 41c. The arithmetic processing unit 41b has a built-in program containing a preset relationship between cooling fluid temperature and elapsed time as shown in FIG. A comparison calculation is performed between the temperature and a preset cooling fluid temperature. Based on this calculation result, the pressure of the fluid passing through the high-pressure circuit 6 and the rotational speed of the motor generator 30 are controlled so that the temperature of the fluid detected by the temperature detector 40 reaches a preset cooling fluid temperature. . That is, the cooling fluid temperature and the pressure of the fluid passing through the high pressure circuit 6, the motor generator 30
There is a relationship as shown in Figure 2 with the rotational speed of
If the detected temperature is lower than the preset cooling fluid temperature, the pressure of the fluid passing through the high pressure circuit 6 and the rotational speed of the motor generator 30 will be the same as the pressure and rotational speed corresponding to the preset cooling fluid temperature. If the detected temperature is higher than the preset cooling fluid temperature, it is increased. In this case, the pressure of the fluid passing through the high-pressure circuit 6 is controlled by a required pulse amount, which is an electrical signal amount outputted based on the comparison calculation result, through the pulse controller 41e and the control motor 3.
9, and also the motor generator 30
The rotational speed is controlled by operating the relays 41f to 41i and changing the combination of operating and inactivating the resistors 34 to 37 to control the load resistance value.

Next, when the fluid temperature after cooling reaches the temperature at which the fluid is introduced into the reservoir 18 (processing unit 41b
The required pulse amount is determined by the pulse controller 41d according to the instruction output from the arithmetic processing unit 41b).
5, the flow rate control valve 14 is opened by a set value and cooling fluid is sent to the reservoir 18.

By continuing the operations described above, the refrigerator is automatically operated.

As described above, according to the present invention, it is possible to automate the operation of the refrigerator, eliminate the need for skilled operating personnel, and save labor in operating the refrigerator.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the refrigerator operating method according to the present invention, and FIG. 2 is a diagram of refrigerator operating characteristics. 1, 18...Reservoir, 2...Drive device, 3...
...Compressor, 4...Pressure regulating valve, 5...Low pressure circuit,
6... High pressure circuit, 7... Safety valve, 8... Multi-stage heat exchanger, 9... Cylinder, 10, 11... Piston, 12... Suction valve, 13... Exhaust valve, 14...
Flow rate adjustment valve, 15, 39... Control motor, 16,
17... Shutoff valve, 19... Cold storage tank, 20, 21...
... Pin, 22, 23 ... Connecting rod, 24 ... Crankshaft, 25, 26 ... Bearing, 27, 29 ... Pulley, 28 ... Belt, 30 ... Motor generator, 3
1, 32...Electric circuit, 33-37...Resistor,
38...Pressure regulating valve, 40...Temperature detector, 41
...Control device, 41a...Power supply device, 41b...
Arithmetic processing unit, 41c...Input/output controller, 41
d, 41e...Pulse controller, 41f to 41i...
...Relay, 41f'-41i'...Electric contact, 42...
...Rotation speed detector.

Claims (1)

[Claims] 1. In a method of operating a refrigerator that cools a pressurized fluid by adiabatically expanding it, the temperature of the cooling fluid is set in advance to a temperature that does not cause stiffness between the components of the refrigerator in the process of lowering the temperature of the refrigerator to a set temperature. a step of detecting the temperature of the fluid that has been adiabatically expanded and cooled by the refrigerator; and a step of detecting the temperature of the detected fluid and the preset cooling fluid temperature corresponding to the time point at which the temperature is detected. a step of calculating in advance the relationship between the temperature that does not cause stiffness, the pressure of the fluid that is increased and supplied to the refrigerator, and the rotational speed of the refrigerator, and the predetermined relationship and A method for operating a refrigerator, comprising the step of controlling the fluid pressure and rotational speed based on the comparison calculation result to adjust the cooling fluid temperature to the preset cooling fluid temperature.