SU819525A1 - Method of automatic regulating of cryogenic helium system - Google Patents

Description

(54) AUTOMATIC REGULATION METHOD OF CRYOGENIC HELIUM SYSTEM # 1

Some of the flow of the expander flow is carried out depending on the magnitude of the deviation, adjusting it for the temperature at the outlet of the object, and the change in the flow rate of the gels through the object is made at its entrance.

The drawing shows a diagram of a system that implements the described method.

The system contains a compressor 1, (connected via a direct stream 2 passing through heat exchangers 3-7 to the cooled object 8. The cooled object 8 is connected to the inlet of the compressor 1 via a return flow line 9. The cryogenic unit contains a preparatory cooling stage 10 with an expander 11 .

An expansion device 13 is mounted on the part 12 of the forward flow 2 directed to the cooled device 8. The gas holder 14 is connected to the return flow line 9 before entering the compressor 1. The temperature of the gel at the outlet of the cooled object is measured by a temperature sensor 15 connected to the controller 16, which controls the actuator of the expansion device 13. A flow sensor 17 is installed on the return flow line 9. A flow sensor 18 / connected to the regulator is installed in the pre-cooling stage A pressure sensor 20 is installed on the forward flow line 2 with a regulator 21 connected to valve 22. The system also includes a controller 23 connected to temperature sensor 15 and the expander. eleven.

The system works as follows.

Helium is injected into compressor 1 and sent to direct flow 2, which through heat exchangers 3-7 enters cooling to facility 8. Flow 2 in each heat exchanger is cooled by reverse flow 9.

A portion of the direct flow 10 is taken to the expander 11 and, after expansion, is returned to the return flow 9. The other part of the direct flow 12 is sent to the cooling object 8. After the expansion device 13, the flow 12 expands to pressure in the cooling object 8. From the cooling facility 8, the flow of gels is directed to the reverse flow 9. To stabilize the suction pressure of the compressor 1, a gas tank 14 is used.

Automatic regulation of the cryogenic helium system operation mode is carried out with the help of a system of sensors, regulators and actuators. With increasing (decreasing) load in the object. The cooling temperature 8 rises (decreases) the temperature at the exit from the object 8, which leads to an increase (decrease) in temperatures and pressures at all nodes of the cryogenic system. The temperature of the flow of gels at the exit of object 8 is decisive for most objects, as the maximum allowable temperature. In the process of regulation, the signal from the temperature sensor 15 is supplied to the regulator 16, which controls the actuator of the expansion device 13. Increasing (decreasing) the performance of the expansion device 13 provides an increase (decrease) in the flow of gels supplied to the cooling object 8, while maintaining set temperature and required cooling capacity. In this case, the reverse flow 9 increases (decreases). Signals from the flow sensor 17 of the return flow 9 and the flow sensor 18 of the flow dilator flow to the regulator 19, and from it, depending on the ratio of the flow, to the device for controlling the performance of the expander 11 ( not shown). If the flow ratio is greater than the set value, then the flow rate of the expander flow is reduced, and if it is less, the flow rate of the expander flow is increased. By changing the flow of the cryoagent supplied to the cooling object 8 and the flow flow, the pressure at the inlet to the installation changes. It is stabilized by changing the flow rate of the direct flow 2 according to the signal from the pressure sensor 20 by the regulator 21, which gives a signal to the actuator of the valve 22.

Maintaining a given ratio of the expander flow and the flow of helium returned from the cooling object ensures optimal operation of the cryogenic system.

For stable operation of the automatic control system, the flow rate of the expander flow is adjusted by the temperature of the cryoagent at the outlet of the cooling object. In this case, the signal from the temperature sensor 15 is fed to the controller 23, and from there to the device for controlling the performance of the expander 11.

Such a schematic solution method. automatic regulation with a proportional-integral control law for regulating devices ensures a reduction in the specific energy consumption by 25% with a given cooling capacity, which according to preliminary calculations will give an annual saving of 3.5 thousand rubles, for a single installation with a cooling capacity of 5,200 watts.

Claims (2)

Claim A method for automatically controlling a cryogenic helium system containing a cryogenic installation with an expander pre-cooling stage connected to the object to be cooled by changing helium consumption through the object according to the temperature of helium at its outlet and through the expander stage, characterized in that, in order to increase efficiency, it is additionally measure helium flow rates at the exit from the object and the flow rate of the expander flow, determine the ratio of these flows, compare with a given value and change in consumption yes, the expander flow is carried out depending on the magnitude of the deviation, adjusting it according to the temperature at the outlet of the object, and the helium flow through the object is changed at its inlet. 5 Sources of information taken into account in the examination 1. A.P. Stoll. Aflexlble multipurpose helium refrigerator. Proceedings of the'Second internatl- 10 onal Cryogenies Engineering Conference. Вrighfon, Un I tad Kingdom, 1968, p. 36. 2. XM-6. Cryogenic and oxygen 15 new mechanical engineering. Cryogenic helium systems. Overview information. TSINTIHimNeftemash, M., 1978, p. 54.