JPS6217640A - Apparatus for measuring sludge level - Google Patents

Abstract

PURPOSE:To obtain a measured result having high reliability, by detecting not only the water level in a tank but also the water head pressure by water and sludge in the bottom part of the tank and calculating the sludge level of tank water on the basis of the detected water level and water head pressure. CONSTITUTION:An ultrasonic type water level detector 9 for detecting the height of the surface 8 of water, that is, a water level H is arranged to the upper part of a sludge tank collecting and storing the radioactive waste liquid from the water treatment apparatus in a plant and a pressure sensor 10 for detecting water head pressure P by sludge 3 and water 4 is arranged to the bottom part of said sludge tank 1. The output signal from the sensor 10 is inputted to an operator 12 through a signal converter 11 and the output signal from the detector 9 is inputted to the operator 12 through a signal converter 13. In the operator 12, a sludge level is calculated on the basis of the water head pressure P detected by the sensor 10 and the water level H detected by the detector 9. The calculated result is displayed on a sludge level display device 14 and supplied to an alarm 7. By this method, the measured result having high reliability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a sludge level measuring device that continuously measures the level of sludge separated from water and settled at the bottom of a tank.

[Technical background of the invention]

For example, in plants such as nuclear power plants, radioactive waste fluid discharged from water treatment equipment is collected in a sludge tank, where the sludge components are precipitated and stored separately from water for a long period of time, allowing the radionuclides to decay. I have to.

The sludge level in the tank provides important information for managing the reception and transfer of waste liquid. Therefore, it is necessary to determine the sludge level in the tank.

In the conventional sludge level measurement, as shown in FIG. 3 increases and the interface 5 between sludge 3 and water 4
When the sludge level (that is, the sludge level) reaches the position of the switch 2, the switch 2 is operated, and the alarm 7 is caused to perform an alarm operation (alarm sound, alarm lamp lighting, etc.) via the converter 6.

[Problems with background technology]

However, in this sludge level measuring device, since the level switch 2 is fixed, continuous measurement is not performed, and the problem is that the level cannot be known until the sludge 3 reaches a predetermined age and the alarm 7 activates. was there.

In addition, in reality, the boundary surface 5 between the sludge 3 and the water 4 is often not clear or the boundary surface 5 is extremely uneven, and due to these adverse conditions, highly reliable measurement results cannot be obtained. There was also the problem that it was difficult to read (q).

Furthermore, since the sludge 3 adheres to the level switch 2, there is also the problem that failures are likely to occur.

Therefore, it has been considered to continuously measure the sludge level using a float type level meter that is always located at the interface 5 between the sludge 3 and water 4. However, in this case, a guide mechanism is required to guide the level meter in the vertical direction, which complicates the configuration and also causes sludge to adhere between the level meter and the guide mechanism, which may impede the movement of the level meter. , there is a high risk of failure, and, like the device shown in FIG. 4, there is also the problem that highly reliable measurement results cannot be obtained due to the conditions of the boundary surface 5, so it has not been put into practical use.

[Purpose of the invention]

The present invention solves these problems by 1+? L:! The purpose was to be able to continuously measure the level of sludge in a tank with a simple configuration, to obtain highly reliable measurement results, and to prevent malfunctions. The object of the present invention is to provide a method for measuring sludge level with less risk.

[Summary of the invention]

The sludge level measuring device of the present invention detects the water level in the tank by the water level detection means, detects the water head pressure due to water and sludge at the bottom of the tank by the pressure detection means, and detects the water head pressure detected by the pressure detection means. Based on the water level detected by the water level detection means, the sludge level in the tank is calculated by the calculation means.

[Embodiments of the invention]

First, a first embodiment of the present invention shown in FIG. 1 will be described.

An ultrasonic water level detector 9 is disposed at the top of a sludge tank 1 that collects and stores radioactive waste liquid from water treatment equipment in a plant as a water level detection means for detecting the height of a water surface 8, that is, a water level H. Further, a pressure sensor 10 is disposed at the bottom of the sludge tank 1 as a pressure detection means for detecting the head pressure P due to the sludge 3 and water 4. The output signal from this pressure sensor 10 is transmitted to a signal converter 1.
After being converted into a standard signal in step 1, it is input to the performance device 12,
The output signal from the water level detector 9 is converted into a standard signal by a signal converter 13, and then input to a calculator 12. The calculator 12 calculates the sludge level based on the head pressure P detected by the pressure sensor 10 and the water level H detected by the water level detector 9. This calculation result is displayed on the sludge level display 14, and is also input to the alarm 7.
The alarm device 7 performs an alarm operation (alarm sound, alarm lamp lighting, etc.) when the sludge level reaches a predetermined value. Note that the arithmetic unit 12 and the signal converter 11.13 constitute the arithmetic means 15. A water level monitoring device 16 is also provided if necessary, but the water level detector 9 can also be used for this purpose.

Calculation of the sludge level h1 in the calculator 12 is performed as follows.

Sludge level (distance from the bottom of sludge tank 1 to interface 5 between sludge 3 and water 4) is hl, distance from interface 5 to water surface 8 is h2, density of sludge 3 is ρ1,
If the density of the water 4 is ρ2 and the acceleration of the m force is Q, then the water head pressure P detected by the pressure sensor 10 is: P-Q+ Q h1+D2Qh2 - (1) On the other hand, the water level H detected by the water level detector is , 1-(-hl
+h2...('2J(
If (from formula 21, the sludge level hi is (ρ1-0
2) Q Dt −,02·=(3),01. ρ2 is a known value because the density of the waste liquid used in the plant is known. Therefore, by setting the arithmetic expression in the processor 12 to the expression (3), the sludge level indicator 14
The sludge level h1 is continuously displayed.

The sludge level measuring device configured as described above can measure the level of sludge in a tank in an Ivt manner with a simple configuration, and can obtain highly reliable measurement results without the risk of failure. It is possible to obtain excellent effects such as:

Next, a second actual example tA shown in FIG. 2 will be explained. This is an example in which a bubbler tube type pressure detection Hf119 equipped with a bubbler tube 18 is used as the pressure detection means.

Inside the sludge tank 1, a bubbler pipe 18 for measuring water head pressure and a bubbler pipe 20 for density measurement are arranged vertically. The lower end of the bubbler tube 18 for measuring head pressure is located close to the bottom of the sludge tank 1, and the lower end of the bubbler tube 20 for density measurement is positioned slightly above the lower end of the bubbler tube 18 for measuring head pressure by Δh.

Bubbler tube 18 for water head pressure measurement and bubbler tube 20 for density measurement
Each has its own style! A measurement air supply device 23 is connected through one regulator 21.22, and the air supply device 23 is configured to supply air to each bubbler pipe 18.20 through a flow rate regulator 21.22. A head pressure converter 24 is connected to the air supply pipe of the bubbler pipe 1811111 for water head pressure measurement, and between the air supply pipe on the bubbler pipe 18 side for water head pressure measurement and the air supply pipe on the density measurement bubbler pipe 20 side. is connected to the differential pressure converter 25. Therefore, when air is supplied from the air supply device 23, the head pressure converter 24
The head pressure P due to the water 4 is detected as the back pressure of the air pushed out from the tip of the bubbler tube 18, and this detection signal is 'a
It is input to the n unit r112 and the divider 26. On the other hand, the differential pressure converter 25 converts the density ρ1 of the sludge 3 into both bubblers I!
The difference in back pressure at 18.20 is detected as a differential pressure ΔP, and this detection signal is also input to the arithmetic unit 12 and the divider 26 as arithmetic means. Note that the water level monitoring device 16 is connected to the divider 26.

Further, a detection signal from an ultrasonic water level detector 9 provided at the top of the sludge tank 1 for detecting the water level H is converted into a standard signal by a signal converter 13 and then inputted to the arithmetic unit 12. .

Therefore, calculation of the sludge level h1 in the computing unit 12 is performed as follows.

The differential pressure ΔP is ΔP-ρ1・Q・Δh...(4)
Further, since the density ρ2 of water is approximately 1, the equation (3) used in the above embodiment becomes as follows, and the sludge level h1 is calculated based on this equation (5).

Therefore, in this embodiment, as in the first embodiment, the level of sludge in the tank can be continuously measured with a simple configuration, and highly reliable measurement results can be obtained.

Next, a third embodiment shown in FIG. 3 will be described.

A water head pressure transducer 24 similar to that of the second embodiment is connected to the lower end of the peripheral wall of the sludge tank 1 as a pressure detection means via a seal mechanism 28, and a water level detection means is connected to the peripheral wall of the tank 1 above it. A water level transducer 29 is connected via a seal structure 30.

As a result, the head pressure transducer 24 has sludge 3 and water 4.
The water head pressure P can be detected by the water level converter 29
In this case, the water level H can be detected.

Therefore, based on the output signals of the bidirectional converters 24 and 29, the sludge level h can be detected by the arithmetic unit 12 as the arithmetic means using equation (3).

In this embodiment as well, the first. As in the second embodiment, the level of sludge in the tank can be continuously measured with a simple configuration, and highly reliable measurement results can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the level of sludge in a tank can be continuously measured with a simple combination, highly reliable measurement results can be obtained, and there is little risk of failure. A sludge level adjustment device can be provided.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a sludge level measuring device showing a first embodiment of the present invention, and Fig. 2 shows a sludge level measurement device showing a second embodiment! FIG. 3 is a schematic diagram of a sludge level measuring device showing a third embodiment, and FIG. 4 is a schematic diagram of a sludge level measuring device showing a conventional example. 1...Sludge tank, 3...Sludge, 4...
Water, 5... Boundary surface, 9... Ultrasonic water level detector (water level detection means), 10... Pressure sensor (pressure detection means)
, 12... Arithmetic unit, 16... Arithmetic means, 24...
Water head pressure converter (pressure detection means), 29... water level converter (water level detection means). Applicant's representative Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 4

Claims (4)

[Claims] (1) A sludge level measuring device that measures the level of sludge that has settled at the bottom of a tank separated from water, including a water level detection means that detects the water level in the tank, and a water head due to water and sludge at the bottom of the tank. A sludge comprising a pressure detection means for detecting pressure, and a calculation means for calculating a sludge level in a tank based on the head pressure detected by the pressure detection means and the water level detected by the water level detection means. Level measuring device. (2) The sludge level measuring device according to claim 1, wherein the water level detecting means is an ultrasonic water level detector. (3) The calculation means calculates h_1=[P/(ρ_1-ρ_2)g]-[ρ_2] based on the head pressure (P) detected by the pressure detection means and the water level (H) detected by the water level detection means /(
ρ_1−ρ_2)]・H (where ρ_1 is the density of sludge, ρ_2 is the density of water, and g is the acceleration of gravity). The sludge level (h_1) in the tank is calculated from the formula: sludge level measuring device. (4) The sludge level measuring device according to claim 1, wherein the pressure detecting means is a bubbler tube type pressure detecting device.