JPS60216222A - Superconductive level gauge for rotary cryostat - Google Patents

Abstract

PURPOSE:To simplify the adjustment with a simpler functions of a power source and an arithmetic unit by dividing revolutions of a rotary cryostat into several zones to switch control current over to respective zones by stages for the correction of changes in the sensor output to a reference current. CONSTITUTION:Current leads 2a and 3b connected across a liquid surface detection sensor 1 are connected to a control power source 7 to feed signals of signal leads 3a and 3b connected across the sensor 1 to a level display meter 6 through an arithmetic unit 5. Then, the revolutions of a rotary cryostat (not illustrated) are divided into zones to set required control currents for respective zones and a current switched by stages is applied to the sensor 1 from the power source 7. Moreover, variation in the output voltage of the sensor 1 is corrected to the output of a reference current level with the arithmetic unit 5 and converted into the liquid surface to be shown on a display meter 6.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This issue #8J is an improvement of a superconducting liquid level gauge for measuring the liquid level of a cryogenic fluid, such as helium, in a rotating cryostat such as a rotor of a superconducting generator. It is related to.

[Prior art]

Figure 1 is a configuration diagram showing an example of a conventional superconducting liquid level gauge. A liquid level detection sensor with a structure in which wires are stretched, (2a) is a liquid level detection sensor fi+
The (+) side current lead wire connected to one end of the superconducting wire, (
2b) ←) side current lead wire connected to the other end of the superconducting wire, (3a) is a signal lead wire connected in parallel with the (+) side current lead wire to one end of the superconducting wire, (3b) ) is another signal lead wire connected in parallel with the ←) side current lead wire, (4) is the (+) side and (→ side current lead wire # (2a)j (21)) A DC variable power supply (61 is a signal lead wire (3a) and (31)) that can be applied by continuously switching the control current to the liquid level detection sensor il+ by connecting one end of the negative terminal to the liquid level detection sensor il+.
A liquid level display meter that connects one end of the liquid level detection sensor fi+, that is, the voltage output between NN111) and l1, with an appropriate calibration scale to indicate the liquid level f:@, 16) is the signal lead wire (3a). and (3b), and the output voltage f due to the change in the current value applied from the DC variable power supply (4).
i! ) Iiii' is an arithmetic unit that corrects the output to a control current level that is a certain reference.

When the superconducting liquid level gauge configured as described above is applied to a rotating cryostat, for example, the rotor (not shown) of a 60Hg AC j11-pole superconducting generator, in this case, liquid helium that is annularly stuck to the inner wall of the cylindrical container The thickness of the layer will be measured. Attach a liquid level detection unit (1) with an appropriate span length to the required position depending on the shape and dimensions of the cylindrical container, and connect each lead wire (2a).

Connect (2b), (3a) and (3b) to the outside of the rotor via a slip ring as shown in Figure 1.

The liquid level is measured as follows.

The rotation speed of the rotor ranges from a stationary state to 3600 rpm. The liquid level detection sensor (I+
Adjust the control current applied to the In other words, the value of the control current applied from the DC variable power supply j41 to the liquid level detection sensor fl+ is continuously switched depending on the rotation speed of the rotor, and even if the rotation speed changes, the liquid level detection sensor (1) is always The optimum control current is always applied in several ranges.

When liquid helium is contained in the rotor, the part of the superconducting wire that is the liquid level detection sensor fil that is immersed in the liquid transitions to a superconducting state and has zero electrical resistance, while the part exposed to the gas phase In a normal conducting state, it exhibits an electrical resistance that is approximately inversely proportional to the height of the liquid level. This characteristic is used to detect the helium liquid level. However, in a rotating cryostat, the centrifugal force acts on the helium, so the thermodynamic state of the internal helium and the flow obstruction pattern constantly change as the rotation increases, and as the rotation increases, the liquid level detection sensor The amount of heat transferred from 11.1 to helium increases as the centrifuge becomes higher.

If the control current applied to the liquid level detection sensor (1) is small, the amount of heat removed from the behelium exceeds the amount of heat generated in the part exposed to the gas phase, and the entire part of the Super ``1! changes to the super*4 state, and behaves as if the apparent north liquid level has increased.On the other hand, if the control current is too large in the low rotation range, the apparent The liquid level appears to have dropped, and the true liquid level cannot be detected.

FIG. 2 is a characteristic diagram showing an example of the relationship t between the minimum control current that can detect the true helium liquid level and the rotational speed when the ultra-single calyx liquid level detection sensor is applied to a rotating cryostat for testing. This sensor is applied to the liquid level detection sensor (1) described above, and the control current 1 DC variable power supply (41
By supplying the helium from the engine, unnecessary evaporation loss of helium can be suppressed in each rotation range, and the helium liquid level can be detected with high accuracy. The voltage output of the liquid level detection sensor (1) detected in this way is corrected to the standard control current level output by the calculator (6), and the kneading value is input to the liquid level display needle (5). will be displayed.

However, in the superelectric ## liquid level needle configured as above, the control current is continuously variable according to changes in the rotation speed, which requires a highly functional DC variable power source and arithmetic unit, making it expensive. There were drawbacks such as the need for adjustment.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as mentioned above, and takes into account the actual operating conditions of a rotating cryostat and calculates the control current required for each specific rotation speed range that is commonly used. By making it possible to switch the supply to the liquid level detection sensor in stages, 1 [Super Ii for rotating cryostat that is easy to obtain and easy to adjust by simplifying the functions of the source and computing unit! The purpose is to provide a specialized liquid level gauge.

[Embodiments of the invention]

Figure 3: The invention of tobacco! This is a configuration diagram showing IJ. In the figure, +11, (2a), '(2b), (3
a), (3b), t6+, and (6) are the same parts as the conventional ones, and (7) is determined by the operating mode of the rotating cryostat, etc. The control current (constant current) required for each region is set respectively, and the liquid level detection sensor (1
) is a ratio controlled power supply.

The liquid level gauge of this actual example constructed in this way is applied to the rotor of the superconducting generator described in L to measure the liquid level.

The rated rotation speed of the rotor is 3,600 rpm, and the rotation speed is low (constant) for liquid helium cooling during initial cooling and cold storage operation, which is performed in a standby state by interrupting the ignition during steady operation. It is done. The number of rotations varies depending on the rotor diameter, etc., but is usually several hundred to 11,000 rpm, taking care not to peel off the liquid helium stuck to the rotating cylinder wall.
The rotation speed is set to an appropriate level.

In this way, in a rotating cryostat, such as a rotor, which cannot operate in a limited number of rotational speed ranges, it is necessary to accurately detect the liquid level in each determined rotational speed range, which may pose a practical problem. do not have.

Therefore, once the operating pattern of the rotor is determined, the rotation speed range is divided into an appropriate number, and the appropriate control current is switched in stages for each target rotation speed range and applied to the liquid level detection sensor. , just measure the liquid level.

FIG. 4 is a characteristic diagram showing an example of a control current applied to the liquid level detection sensor that is switched in stages. This is done using a liquid level detection sensor ill with the characteristics shown in Figure 2.
Considering the liquid level measurement in the rated operating range of m, the rotation speed range is divided into three, and the control current is adjusted in stages according to the convenience of the rotation speed.
This is a platform for changing stages.

That is, the required number of control currents with different values can be applied to the liquid level detection sensor from the control power source (7), and the rotation speed of the rotor is detected by a device equipped with a switching function such as a tachometer meter relay. Since the pressure is applied to switch the control current for each set rotational speed range, the liquid level in the target rotational speed range can be detected with high accuracy. In addition, the computing unit (6) that corrects the output of this platform and the liquid level detection sensor il+ is configured to take any appropriate value of current as the reference value, and calculate an appropriate value for the remaining fidget current value. It is a good idea to provide the necessary number of voltage dividers (resistors) to correct it.

According to this actual example, it becomes easy to adjust and set the control current and correct one output word of the liquid level sensor, and the functions of the control power supply and computing unit can be simplified, making it possible to simplify the equipment configuration. became cheaper.

Furthermore, as can be seen in the example of the operation of the rotor of a superconducting generator, it has great practical effects, such as making it possible to economically measure the liquid level in accordance with the actual operating conditions of a rotating cryostat. .

〔Effect of the invention〕

As explained hereafter, the present invention includes a liquid level detection sensor that detects the liquid level of a cryogenic fluid contained in a rotating cryostat using four superelectric wires, and a liquid level detection sensor that detects the liquid level of a cryogenic fluid contained in a rotating cryostat using four superelectric wires. A control power supply that divides the number into several divisions and applies a control current by switching it stepwise for each rotational speed ML according to changes in the rotational speed, and an output of a liquid level detection sensor in accordance with changes in the current value of this control power source. The functionality of the power supply and calculator is improved by equipping it with a calculator that corrects the amount of voltage fluctuation to the reference current level output, and a liquid level indicator that converts the correction signal and displays the liquid level. Since it can be simplified and the adjustment becomes easy, it is possible to obtain a superconducting liquid level needle for a rotating cryostat that is easy to obtain, simple, and has no practical problems.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an example of a conventional superconducting liquid level gauge for a rotating cryostat, FIG. 2 is a characteristic diagram showing an example of a control current applied to a conventional liquid level detection sensor, and FIG. 3 is a diagram showing an example of a control current applied to a conventional liquid level detection sensor. -j! FIG. 4 is a block diagram showing one example of a liquid-introducing meter for superfluous output from a rotating cryostat, and FIG. 4 is a characteristic diagram showing an example of a stepwise switching control current applied to the liquid level detection sensor of the present invention. In the figure, (1) is a bald surface detection sensor, (51) is a liquid level indicator, (6) is an arithmetic unit, and is a +71 Vi control power source. Agent Masuo Oiwa Figure 1 r----------4--l!] $i7 Lio λ?
-z) a+11 personnel (2 in Figure 2 IX) +IkU/V trpm) Figure 3 ``-111 Rotation of the fly ostat is further increased! Figure 4 11-I Kotokuju N (rPm

Claims (1)

[Claims] Ultra-low Il housed in a rotating cryostat with a super humiliating thin wire! A liquid level detection sensor detects the liquid level of the fluid.The liquid level detection sensor divides the rotational speed of the rotating cryostat into several divisions, and the control current is switched stepwise for each rotational speed range according to changes in the rotational speed. A control power source to be applied, an arithmetic unit that corrects the fluctuation amount of the output voltage of the liquid level detection sensor due to a change in the current value of the control power source to an output of a reference current level, and a calculation unit that converts the correction signal described in E to calculate the liquid level. A superconducting liquid level gauge for rotating cryostat equipped with a liquid level indicator.