JPH08292080A - Differential pressure type water level measuring device - Google Patents

Abstract

PURPOSE: To make accurate stage measurement and water level control achievable even in those of tanks whose pressure in unstable. CONSTITUTION: A level switch 4 is set up in a pipe 6 which performs the same level change as a reference surface apparatus 2, detecting a variation in a reference water head, and a make-up valve 5 is opened or closed by means of on-off control, supplying water, whereby the reference water head is always held aright and thus an accurate water level is securable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential pressure type water level measuring device, and more particularly to a differential pressure type water level measuring device for measuring the water level of tanks with unstable pressure.

[0002]

2. Description of the Related Art In a conventional device, as shown in FIG. 3, a reference surface 2 is installed on a low pressure side pressure guiding pipe 8 to secure a reference head.
A water level change in the tank 1 is detected as a pressure change in the high pressure side pressure guiding pipe 9, and the differential pressure is measured as a water level.

The differential pressure of the water head of rh2 from the reference level device 2 of the low pressure side pressure guiding pipe 8 to the water level gauge 3 and rh1 from the reference level of the high pressure side pressure guiding pipe 9 (0% level) is corrected to a zero point, The change in the water level H of the tank 1 is detected as the head pressure on the high pressure side, and the water level is measured. Therefore, if the reference water head is lowered, the zero point correction is deviated, resulting in an error in water level measurement.

As a method of improving this error factor, for example, as disclosed in JP-A-56-42111, a reference level gauge installed on the low pressure side pressure guiding tube and a detection pipeline on the upstream side (tank side) of the reference level gauge are installed. By installing an orifice at the joint, the outflow rate of water in the reference surface was restricted and the change in the reference head was reduced.

Further, conventionally, a total of four pressure gauges are installed near the tank detection seat and near the water level gauge in the low-pressure side and high-pressure side pressure guiding pipes, respectively, as in JP-A-59-176626. Install two calculators, input the pressure gauge signal to the calculator,
The instructions of the water level gauge were corrected.

[0006]

In the prior art, when the pressure in the tank becomes a negative pressure due to the change of the plant load,
The water in the reference surface device is flushed or sucked into the tank, which lowers the reference water head, and the zero point correction on the low and high pressure sides is deviated, resulting in an error in water level measurement.

As a method for improving the above-mentioned problem, in the prior art, the orifice is installed to limit the outflow of water in the reference surface device and reduce the decrease in the reference head. However, there was a problem such as pressure hunting due to blockage and erroneous water level measurement.

In the latter method, a total of four pressure gauges and two arithmetic units are installed in each of the high and low pressure guiding pipes, and the pressure at each point is detected in response to pressure fluctuations, and the water level measurement value is corrected. However, the configuration of water level measurement becomes a large scale.

An object of the present invention is to provide a differential pressure type water level measuring device which has a simple structure of the water level measuring device and which can always measure an accurate water level irrespective of the pressure change in the tank by removing the element of measurement failure. Especially.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a level switch for detecting a change in water level in a reference surface device, a low pressure side pressure guiding pipe between a tank and a reference surface device, and a reference surface. If it is installed on the reference head pipe connected to the low pressure side pressure piping between the pressure gauge and the differential pressure type water gauge and the reference head is lowered,
A water supply pipe connected to the low-pressure side pressure piping between the reference level gauge and the differential pressure type water level gauge for replenishing water, and a water supply valve that responds to the level switch signal are installed in the water supply pipe to automatically supply water. Replenish and always maintain the standard head.

[0011]

[Function] By providing a level switch for detecting a change in the water level in the reference level and installing a makeup water valve that responds to the signal of the level switch in the water supply pipe and the water supply pipe,
When the reference water head drops, the make-up water valve installed in the water supply pipe is automatically opened by the signal of the level switch to replenish the water and return to the reference water head, so that an accurate water level can be measured at all times.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

According to the present invention, as shown in FIG. 1, one end of the low pressure side pressure guiding pipe 8 and one end of the high pressure side pressure guiding pipe 9 are connected to the gas phase portion and the water phase portion of the tank 1, and the other ends are connected to each other. It is connected to the pressure type water level gauge 3 and a reference leveling device is installed in the middle of the low pressure side pressure guiding pipe 8. A reference water head pipe 6 communicating with the low pressure side pressure piping 8 between the tank 1 and the reference surface level 2 and between the reference surface level 2 and the differential pressure type water level gauge 3 is connected to the level head 4 and the orifice. Install 10. Further, a water supply pipe 7 is connected to the low pressure side pressure guiding pipe 8 between the reference surface 2 and the differential pressure type water level gauge 3, and a makeup water valve 5 is installed in the water supplying pipe 7.

This device prevents the reference water head of the low pressure side pressure guiding pipe 8 from being lowered and always measures an accurate water level. When the pressure of the tank 1 becomes a negative pressure due to the load fluctuation of the plant, When the reference water head is lowered by flushing the water in the level device 2 or being sucked into the tank side, the decrease in the reference water level is communicated with the low pressure side pressure guiding pipe 8 and used as the water level in the reference level device. It is detected by the level switch 4 installed on the reference water head tube 6 having the same water level. Next, the make-up water valve 5 installed in the water supply pipe 6 provided to restore the reference water head by the signal of the level switch is automatically opened / closed by the on / off control to replenish the reduced water in the reference leveler. The standard head can be restored.

Further, the reference water head pipe 6 is provided with an orifice 10 so as to prevent water level pulsation due to abrupt water level change and perform stable water supply control.

FIG. 2 shows a detailed example of the case where the electrode type level switch 4 is used. When the reference water head is maintained, the electrode comes into contact with water to energize, and the make-up water valve 5 is closed. When the reference water head is lowered, the power supply is cut off and an open signal is output to open the replenishment water valve 5 to replenish the water.

Although an example of the electrode type level switch is shown, a float type level switch (inner cylinder type, outer cylinder type) or the like can be used.

With the above structure, it is possible to always hold the reference water head and obtain an accurate water level.

[0019]

According to the present invention, it is effective to accurately measure and control the water level even in tanks where the pressure is unstable.

[Brief description of drawings]

FIG. 1 is a system diagram of a differential pressure type water level measuring device of the present invention.

FIG. 2 is an explanatory view showing an example using the electrode type level switch of the present invention.

FIG. 3 is an explanatory diagram of a differential pressure type water level measurement principle.

[Explanation of symbols]

1 ... Tank, 2 ... Reference level gauge, 3 ... Differential pressure type water level gauge, 4 ... Level switch, 5 ... Make-up water valve, 6 ... Reference water head pipe, 7 ... Water supply pipe, 8 ... Low pressure side pressure pipe, 9 ... High pressure Side pressure piping, 1
0 ... Orifice.

Claims (1)

[Claims] 1. A gas phase portion and a water phase portion of a tank are connected to one end of a low pressure side and a high pressure side pressure guiding pipe, and the other end is connected to a differential pressure type water level gauge, respectively, on the way of the low pressure side pressure guiding pipe. In the differential pressure type water level measuring device to install a reference surface device, in the low pressure side pressure guiding pipe between the tank and the reference surface device, the low pressure side pressure guiding pipe between the reference surface device and the differential pressure type water level gauge A level switch for detecting a change in the water level in the reference surface device is installed in the connected reference water head pipe, and a reference head is provided in the low pressure side pressure piping between the reference surface device and the differential pressure type water gauge. When it drops, a water supply pipe for replenishing water is connected, and a water supply valve that responds to the signal of the level switch is installed in the water supply pipe, which makes it possible to always maintain the reference water head. Differential pressure type water level measuring device.