JPS59174484A - Measuring device for water level in tank - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to the measurement of liquid level in a tank of a nuclear power plant, and is particularly suitable for preventing measurement errors of an ultrasonic liquid level gauge due to the generation of vortices on the liquid surface. This invention relates to a water level measuring device in a tank.

[Prior art]

The conventional tank water level measuring device has an ultrasonic water level gauge 2 (1) installed in the center of the tank top lid 4 as shown in Fig. 1.
・The liquid level was measured by transmitting ultrasonic waves directly to the water surface in the tank, but when draining the tank liquid 17, the pump 10 was started and a part of the drain liquid was passed through the circulation piping. The liquid level 16 in the tank 1 is (1) because the liquid is returned to the tank 1 and the jet pump 3 is driven to agitate the inside of the tank 1.
It is known that the measured water level is lower than the actual water level. For this reason, there is a drawback that when the water level is low, the pump 10 is stopped, and when the water level is high, the pump 10 is started at a water level other than the designed water level.

where h: liquid level ho: liquid maximum water level r: distance from the center of the tank when the liquid level is high: a constant specific to the system shown in Fig. 1 [Object of the Invention] The object of the present invention is to An object of the present invention is to provide a tank water level measuring device that appropriately measures water level.

(2) [Summary of the Invention] In the present invention, the surface water level when draining the tank while stirring it may not be as shown in equation (1). It can be easily determined by measurement, and by floating a thin disk with a diameter above the liquid level in the tank, the position of the thin disk can be measured with an ultrasonic water level gauge, so the maximum liquid level is (2) The equation υhL - the position of the thin disk can be easily calculated, and the accuracy of water level measurement can be improved.

Examples of the invention] An embodiment of the present invention will be explained below with reference to FIG.

A thin disk 6 having the diameter shown in FIGS. 2 and 3 is floated on the liquid level in the tank. Four guide rods 7 of the same length are attached to the side surfaces of the thin disk 6 to move up and down along the wall surface of the tank 1 so that the thin disk 6 is always located at the center of the tank.

An ultrasonic water level gauge 2 for measuring the position of the thin disc 6 is installed in the center of the tank top lid 4. Here, the minimum diameter of the thin disk 6 is such that it covers the effective range of the ultrasonic water level gauge 2 when the thin disk 6 is located at the bottom of the tank 1 (3)
Determine by formula.

Here, HT: tank height θ: Effective range of ultrasonic water level gauge FIG. 5 is a diagrammatic representation of the calculation method of equation (3).

Therefore, the actual highest liquid level according to equation (1) is determined by equation (4).

h: Thin disc position measured by the ultrasonic water level meter By incorporating this equation (4) into the calculator 18, the maximum water level of the liquid (2) is automatically calculated, and from this calculated water level, the pump 10 The reliability of water level control can be improved by starting and stopping the system.

〔Effect of the invention〕

According to the present invention, since the maximum liquid level can be measured, there is an effect of improving the reliability of water level control.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the conventional embodiment device, Figs. 2 and 3 are front and side views of a thin disk, Fig. 4 is an explanatory diagram of the embodiment device of the present invention, and Fig. 5 is a thin circular plate. It is a figure which shows the calculation basis of the minimum diameter D0 of a board. 5... Drain pipe, 8... Overflow pipe, 9...
... Tank inflow pipe, 11... Pump cut-off switch, 13... To tank pit, 14... To outlet, 1
5...Instrumentation cable, 17...Liquid. Agent Patent Attorney Akio Takahashi / f75 diagram-529-

Claims (1)

[Claims] 1. In a tank liquid level measurement device consisting of a tank containing liquid and an ultrasonic water level gauge installed in the center of the tank top lid to measure the liquid level in the tank, the liquid has a small specific gravity and always measures the liquid level in the tank. A thin disk with a guide rod attached to the side to be located in the center is floated on the liquid level in the tank, and a calculator is installed to calculate the water level in the tank by measuring the position of this thin disk. Features: Tank water level measuring device.