JPS5819210B2 - liquid pressure measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure measuring device for active and toxic liquids such as liquid metals.

Calibration of a diaphragm pressure gauge for measuring the pressure of active and toxic liquids such as liquid metals has conventionally been carried out by draining the liquid to be measured, replacing it with a gas atmosphere, and changing the gas pressure.

In other words, in a conventional liquid pressure measuring device, a diaphragm-type pressure transmitting device (generally a diaphragm) is attached to the end of a thin tube branched from the fluid piping main pipe, and a pressure transducer is attached at the end of the thin tube. .

For this reason, it is not possible to perform calibration tests online, and in order to completely fill the liquid to be measured up to the diaphragm type pressure transmitting device in the pressure measuring device as described above, this pressure transmitting device must be used. It needs to be placed below the outlet of the piping main pipe, but in order to completely drain the liquid to be measured, this is not possible with this mounting position and it is necessary to reverse the position. There are some drawbacks.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional difficulties, and to provide a liquid pressure measuring device that can calibrate a liquid force meter online, has a simple configuration, and is capable of improving calibration accuracy. shall be.

The present invention adds a tank with a free liquid level to a conventional liquid pressure measuring device, connects a portable gas pressure variable device to the gas phase of this tank, and calibrates the pressure gauge using the gas pressure. In addition to being able to be carried out in a line, it is possible to completely fill and drain the liquid to be measured without forming a gas space between the pressure transmitting device and the piping main pipe.

The present invention will be described below based on an illustrated embodiment.

In the figure, reference numeral 1 denotes a piping main pipe for the liquid to be measured, and thin tubes 2 are attached to the piping main pipe 1 in the form of branches.

The tip of this thin tube 2 is connected to a diaphragm pressure transmitting device 3 via a stop valve Vl.

A diaphragm or other suitable diaphragm 4 is installed inside the diaphragm pressure transmission device 3 so as to divide it into two parts.
The diaphragm pressure transmitting device 3, which is separated from the capillary 2 by the diaphragm 4, is provided with a liquid pressure gauge 5 capable of detecting the pressure transmitted via the diaphragm 4, and also has a diaphragm pressure gauge 5 that can detect the pressure transmitted through the diaphragm 4. A connecting pipe 6 is provided protruding from the transmission device 3 portion.

The connecting pipe 6 is provided with a stop valve V-2 and a fin 7, and its tip is connected to a vertically placed small-diameter tank 8.

A liquid level detector 9 composed of a thermocouple or the like is installed in the tank 8 in order to measure the liquid level inside the tank 8. It is connected to the display 10.

A communication pipe 11 is provided protruding from the upper end of the tank 8 as shown in the figure, and this communication pipe 11 is connected to the stop valve V-3 and the communication pipe 1.
1 is connected to a portable gas pressure variable device 13 via a connector 12 that is detachably provided to the gas pressure variable device 13.

The portable gas pressure variable device 13 includes a gas tank 14, a gas pressure gauge 15, a gas cylinder 16, and various valves V-4 and V-
It consists of 5, V-6, and V-7.

The communication pipe 11 is connected to a gas pressure regulating valve V- provided in the thin pipe 17.
4 to the gas tank 14.

The gas tank 14 is provided with a gas pressure gauge for measuring the internal pressure of the gas tank 14, a gas pressure regulating valve V-5 for reducing the pressure of the gas tank 14, and a thin tube 18. Gas pressure regulating valve V
-6 and a gas stop valve V-7, which are connected to the gas cylinder 16 in series.

In addition, in the figure, H-1 is the electric heater provided at the stop valve ■-1 and the diaphragm pressure transmission device 3 position, and ■-2 is the fin 7.
An electric heater provided at the tank position H-3 is an electric heater provided at the tank 4 position.

In addition, when measuring the pressure of a liquid to be measured such as metallic sodium which is solid at room temperature, the electric heaters H-1 and H
In addition to -2 and H-3, it is preferable to provide an electric preheater around piping and equipment filled with liquid to prevent solidification of the liquid.

Next, the operation will be explained.

At this time, the liquid to be measured is liquid metal sodium that solidifies at room temperature.

Table 1 shows the operating states of the valves and electric heaters during operation and calibration testing of the device of the present invention.

First, during normal operation, the stop valve V-2 is fully closed, the liquid to be measured between this valve V-2 and the piping main pipe 1 is preheated by the electric heater H1, and the liquid metal sodium is solidified. To prevent.

On the other hand, in order to solidify the sodium from the stop valve V-2 to the tank 8, the electric heaters 1 (-2, H to 3) are kept in the OFF state.

Further, in order to prevent the sodium from melting due to heat conduction from the heating section of the electric heater H-1, the sodium is naturally cooled by the fins 7 to freeze the sodium.

The gas in the tank 8 is maintained in an inert gas atmosphere by fully closing the stop valve V-3.

At this time, the diaphragm pressure transmitting device 3, the tank 8, etc. are provided vertically in a straight line as shown, and the diaphragm 4 is provided so as to vertically divide the diaphragm pressure transmitting device 3 into two. Therefore, a gas space is not formed in the diaphragm 4 portion when filling with the liquid to be measured, which solves the problem of delay in pressure response caused by the effect of gas compressibility, and also prevents liquid from flowing out from inside the device. completely drained.

Therefore, even if, for example, the diaphragm 4 is damaged and it is necessary to remove the device from the piping main pipe 1 for repair, the work can be carried out safely.

Next, the procedure for on-line pressure calibration of a liquid pressure gauge will be explained.

The operating procedure for transitioning from the liquid pressure measurement state during normal operation to the online pressure calibration test state is as follows to prevent damage to the equipment due to volumetric expansion of sodium and inert gas caused by heating of the electric heater attached to the equipment. It is carried out according to the procedure.

(1) First, the thin tube 17 of the portable gas pressure variable device 13 and the communication tube 11 of the tank 8 are connected via the connector 12.

(2) Next, confirm that the valve opening degrees of the gas stop valves V-7 attached to the gas cylinder 16 of the portable gas pressure variable device 13 and the gas pressure regulating valve I-5 of the gas tank 14 are fully closed.

■ Next, in order to communicate the gas phase of the tank 8 with the gas tank 14 of the portable gas pressure variable device 13, a stop valve V is installed.
-3 and gas pressure regulating valve V-4 are fully opened.

(2) After checking the opening states of the valves V-3 and V-4, power is applied to the electric heaters H-2 and H-3 in order to melt the sodium between the tank 8 and the stop valve V-2.

At this time, electricity is first applied to the electric heater H-3, and after melting the sodium in the tank 8, the electric heater H-2 is turned on.
energize.

■ After melting the sodium, fully close the stop valve V=1,
After confirming that it is fully closed, fully open stop valve V-2.

(2) Next, an operation is started to calibrate the liquid pressure gauge 5 using gas pressure.

First, the gas pressure regulating valve V-4 of the portable gas pressure variable device 13 is fully closed.

Next, after confirming that the gas pressure regulating valve V JV 5 is fully closed,
Fully open the gas stop valve V-7 of the gas cylinder 16.

Then, the gas pressure in the gas tank 14 is increased to the calibrated maximum pressure value by the gas pressure regulating valve V-6, and is completely closed again.

Thereafter, the valve opening degree of the gas pressure regulating valve V-4 is gradually opened from the fully closed state, and the diaphragm 4 portion of the diaphragm pressure transmission device 3 is pressurized.

When the gas pressure regulating valve V-4 is fully opened and the indicated value of the gas pressure gauge 15 of the gas tank 14 has stabilized, read the difference between the indicated value of this gas pressure gauge 15 and the indicated value of the liquid pressure gauge 5. .

This difference is the error of the liquid pressure gauge 5.

Next, in order to gradually lower the gas pressure in the gas tank 14 below the maximum calibrated pressure value, the gas pressure regulating valve V-5 was slightly opened, and the reading on the gas pressure gauge 15 in the gas tank 14 dropped to the desired pressure value. At this point, fully close the gas pressure regulating valve ①-5 again.

Then, when the indicated values of the gas pressure gauge 15 and the liquid pressure gauge 5 have stabilized, the difference between the indicated values is read.

(2) When the above calibration test of the liquid pressure gauge 5 is completed, first, the stop valve V=2 is fully opened, and the stop valve V-1 is fully opened, and the sodium pressure measurement begins.

■ Next, turn off electric heaters H-2 and H-3,
Solidify the sodium in the upper part of the figure from the stop valve V-2.

(2) When the above operations are completed, fully close the stop valve I-3 and the gas pressure regulating valve V-4, and remove the portable gas pressure variable device 13 from the connector 12.

As explained above, according to this embodiment, since a gas pressure gauge is used as the standard pressure gauge, it is possible to improve the accuracy and calibration accuracy of the standard pressure gauge. The structure is simple.

Furthermore, since the liquid pressure gauge calibration test is conducted under actual usage conditions, pressure gauge calibration calculations are simple and errors are less likely to occur.

Furthermore, the stop valve V-2 is connected to the pressure receiving part of the diaphragm pressure transmission device.
Since no gas space is formed in sodium up to
The responsiveness of the pressure gauge is improved.

The above description has been made based on the preferred embodiments of the present invention, but according to the present invention, it is possible to calibrate a liquid pressure gauge on-line.

[Brief explanation of the drawing]

The drawing is a schematic diagram showing an embodiment of the present invention. 1... Piping main pipe, 2... Thin tube, 3...
...Diaphragm type pressure transmission device, 5--Liquid pressure gauge, 6--Connecting pipe, 8--Tank, 1
1...Connection pipe, 12...Connector, 13
・・・・・・Portable gas pressure variable device.

Claims (1)

[Claims] 1 A diaphragm-type pressure transmission system in which a thin tube is provided in the form of a branch in the piping main tube for active and toxic liquids such as liquid metals, the end of this thin tube is divided into two by a diaphragm, and a pressure transducer is installed on one side of the thin tube. In a liquid pressure measuring device connected to the other side of the device, a first stop valve is provided in the capillary, and a connecting pipe having a second stop valve is provided on the connection side of the capillary with respect to the diaphragm of the pressure transmitting device. A communication pipe having a third stop valve is provided at the upper end of the tank, and the communication pipe is detachably connected to a gas pressure variable device for pressure calibration. Liquid pressure measuring device.