JPH06328010A - Detection method of sludge collection amount - Google Patents

Abstract

(57) [Summary] [Purpose] To maintain the soundness of the rotating container and reflect it in the process control. [Structure] Attaching a strain gauge 2 to the end plate of the rotating container 1,
The strain gauge 2 detects the amount of deformation. Since the resistance value of the strain gauge 2 changes according to the deformation amount of the rotary container 1, the sludge collection amount is regarded as a change in voltage, and the sludge collection amount is obtained by comparing it with a calibration curve prepared in advance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a solid-liquid separator using a rotary container for sedimentation and removal from a solution by the action of centrifugal force, or a centrifugal concentrator suitable for separating sludge in sewage. The present invention relates to a sludge trapping amount detection method for detecting the amount of sludge trapped in a rotary container.

[0002]

2. Description of the Related Art For example, in a nuclear fuel reprocessing step, an insoluble residue contained in a nitric acid solution of a spent fuel is sedimented and removed from the solution by a centrifugal force by a solid-liquid separator.

The conventional solid-liquid separator is not provided with a means for directly detecting how much solid content, that is, sludge, is retained in the rotary container for collecting solid particles. Therefore, a method of indirectly obtaining the amount of sludge collected from the flow rate of the supply liquid, the estimated particle concentration of the liquid to be treated, and the collection efficiency of the solid-liquid separator is adopted.

[0004]

However, it is very difficult to measure the particle concentration in the liquid to be treated online because the liquid to be treated in the reprocessing step has a high radioactivity level. It is very difficult to keep the amount of sludge actually collected by the solid-liquid separator constant due to fluctuations in process conditions.

That is, when the process conditions change for some reason and a liquid having a high solid content concentration flows into the solid-liquid separator, excessive sludge is accumulated in the rotary container, and the centrifugal force acting on the sludge. As a result, it is conceivable that the rotating container will be subjected to high stress exceeding the allowable stress and will be centrifugally broken.
Therefore, the following measures are necessary to avoid such an event.

For example, the following method can be considered in order to prevent the centrifugal damage of the rotary container even when the sludge occupies the whole of the rotary container. (1) The rotation speed during operation is set to a low value in advance so that there is a margin in the strength against centrifugal stress.

(2) The process conditions are accurately adjusted to control the concentration of sludge so as to prevent collection of a solid content above a predetermined amount. (3) Reduce the volume of the rotary container and the amount of sludge accumulated.

However, lowering the rotation speed as in the method (1) leads to a reduction in sludge separation performance,
In addition, adjusting the process conditions accurately like the method of (2) is actually very difficult because the liquid to be treated to be treated has a high radioactivity level, and is not an effective means. Further, reducing the volume of the rotating container as in (3) leads to a reduction in operation efficiency, which is impractical.

The present invention has been made to solve the above-mentioned problems, and constantly measures the weight of sludge collected in the rotary container online during operation of the solid-liquid separator to excessively collect sludge. An object of the present invention is to provide a method for detecting the amount of sludge trapped, which can prevent the danger from occurring and maintain its soundness and reflect it in process control.

[0010]

DISCLOSURE OF THE INVENTION The present invention uses a solid-liquid separator of the type in which a solid component in a liquid is settled and removed by utilizing centrifugal force to detect the amount of sludge collected in a rotary container. In the method of detecting the amount of collection, the amount of deformation of the rotating container due to the centrifugal force is measured, and the weight of the sludge collected inside the rotating container is obtained from the comparison between the amount of deformation and a calibration curve created in advance. To do.

[0011]

In the centrifugal type solid-liquid separator having the vertical open container of the lower open type, the rotary container during operation is deformed to bulge outward as shown in FIG. The amount of deformation (strain) is sensed by, for example, a strain gauge, and an electric output proportional to the amount of deformation is obtained.

That is, the strain gauge 2 is attached to the rotary container 1 as shown in FIG. 2, and the circuit for supplying current to the bridge circuit, the circuit for amplifying the signal, and the signal as radio waves are transmitted as shown in FIG. Configure a device consisting of a circuit.

This device is integrally attached to a portion which is not easily affected by radiation or the like, for example, the rotating shaft 3 above the radiation shielding plug, and the lead wire connected to the strain gauge 2 is wired through the shaft having a hollow structure. A circuit that receives a signal and extracts an output corresponding to the amount of distortion is installed in a non-rotating portion that is separated from the shaft.

Therefore, the amount of deformation of the rotary container 1 is measured by the strain gauge 2, and the amount of deformation is operated by comparing the amount of deformation with the previously prepared calibration curve of the amount of strain and the amount of accumulated sludge. It can be determined by the state.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a sludge trapping amount detecting method according to the present invention will be described with reference to FIGS. 1 is a vertical cross-sectional view of a centrifugal solid-liquid separator, FIG. 2 is a schematic view of a deformed rotary container in FIG. 1, and FIG. 3 is a bridge circuit for measuring the resistance value of the strain gauge in FIG. And the transmission system circuit of the signal.

In FIG. 1, a rotating container 1 has a strain gauge 2 attached to the upper surface thereof and is suspended by a shaft 3. The shaft 3 is connected to a motor 5 via a coupling 4. The shaft 3 is attached to the bearing housing 7 by bearings 6a and 6b.

The liquid to be treated is supplied from the supply nozzle 8 into the rotary container 1, and the sludge (solid content) 10 in the form of fine particles contained in the liquid to be treated is separated by the centrifugal force to rotate the rotary container 1.
Deposited inside. The accumulated sludge 10 is washed by the washing nozzle 9.

Since the sludge 10 rotates at the same rotational speed as the rotary container 1, a centrifugal force is generated as in the following equation. Centrifugal force F = rω ² m where r: radius of rotation ω: angular velocity m: mass The rotating container 1 is subjected to centrifugal stress due to the mass of the sludge 10 and pushes the rotating container 1 outward as shown in FIG. Transforms into shape. In FIG. 2, the dotted line indicates when the rotary container 1 is stopped,
The solid line schematically indicates the time of rotation.

The strain gauge 2 is attached to an appropriate position on the surface of the rotary container 1, for example, an end plate or a side surface, in order to detect the amount of deformation of the rotary container 1 and to extract it as an electric signal, and then the FM transmission / reception is performed. It is configured to be taken out by means of a machine or the like.

As the electric signal transmission system circuit, the bridge circuit 11 shown in FIG. 3 is used. In FIG. 3, reference numeral 12 is an oscillation circuit, 13 is a chopper circuit, 14 is an AC amplification circuit, 15 is a voltage controlled RF oscillation circuit, 16 is a buffer amplification circuit, 17 is an antenna, 18 is a bridge voltage generation circuit, and 19 is sensitivity setting. The container and 20 are power supplies, respectively.

When the sludge 10 is discharged, the rotation speed is lowered at the time when a predetermined amount of liquid is treated, and the cleaning nozzle 9 is discharged.
The structure is such that washing water is sprayed from there to wash off.
The rotary container 1 is subjected to centrifugal stress due to the mass of the sludge 10 collected inside and the mass of itself, and is deformed to a state in which it is slightly bulged outward as shown in FIG. Since the amount of deformation can be grasped as a change in voltage as the amount of sludge 10 accumulated, that is, the amount of trapped sludge 10, the bridge circuit shown in FIG.
Detected by 11.

This bridge circuit 11 is transmitted by a slip ring or a transmitter and taken into a measurement control system to monitor the amount of sludge trapped. The amount of sludge is obtained by comparing the amount of deformation with a calibration curve prepared in advance.

Next, a second embodiment of the present invention will be described with reference to FIGS. In FIG. 4, a sensor 21 is provided close to the side surface of the rotary container 1, and the sensor 21 is connected to the preamplifier 22.
Connected to the FFT analyzer 23 and D
C Power supply 25 is connected. The FFT analyzer 23 is connected to the control computer 24. The control computer 24 is connected to a solid-liquid separator control panel (not shown).

Here, an eddy current type displacement gauge is used as the sensor 21. The eddy current displacement meter can output a DC voltage proportional to the distance from the rotating container 1 without contact.

In this embodiment, the distance (DC voltage) between the rotary container 1 and the sensor 21 at the time of stop is measured in advance, and the voltage of the DC component obtained by removing the vibration component from the output of the sensor 21 at the time of rotation is used. Find the difference between. This makes it possible to measure the amount of deformation of the rotary container, that is, the amount of sludge collected, in comparison with a calibration curve prepared in advance.

FIG. 5 shows the relationship between the output voltage and the rotation synchronizing component. The broken line shows the baseline at the time of stop and the dotted line shows the baseline at the time of rotation. Next, a third embodiment of the present invention will be described with reference to FIGS.

In FIG. 6, a reflecting mirror is provided on a part of the rotary container 1.
26 is attached, laser light 27 is applied to this, and the reflected light 28 is received and detected using an appropriate light receiving element 29 (A, B, C, D).

When the rotary container 1 is deformed by centrifugal force, the angle of the reflecting mirror 26 with respect to the optical axis also changes accordingly. Therefore, by detecting the change of the reflected light 28 with respect to the incidence of the laser light 27 by the light receiving element 29 (A, B, C, D), the deformation amount of the rotary container 1, that is, the sludge collection amount can be measured. .

In the embodiment shown in FIG. 6, a plurality of light receiving elements 29 (A,
(B, C, D), as shown in FIG. 7, from the no-load rated rotation to the overload rotation is detected in four stages. Next, with reference to FIG. 8 and FIG. 9, a test example in which a strain gauge is actually attached to the surface of the rotary container and a water flow operation is performed using water will be described. In addition, FIG. 8 is a rotary container 1 of an upper open type solid-liquid separator different from the rotary container 1 of the solid-liquid separator shown in FIG.
1 is shown, and the rotary drive unit is omitted because it is almost the same as in FIG.

That is, in FIG. 8, the strain gauge 2 is attached to a position on the side surface of the rotary container 1, and the shaft 3 is rotated by a rotary drive device (not shown) to increase its rotational speed. The recorded output of the strain gauge is shown in FIG. In FIG. 9, the vertical axis represents strain gauge output, and the horizontal axis represents time.

As is clear from FIG. 9, the stress acting on the rotary container increases linearly from the start of water supply, and the load (liquid amount in the rotary container) and the strain amount are proportional. Therefore,
If you make a calibration curve from sludge weight and strain amount in advance, how much sludge will be in the rotating container 1 from the output of the strain gauge 2
It is possible to know during operation whether 10 is accumulated.

According to this test example, it is possible to continuously monitor the amount of the sludge collected while the solid-liquid separator is in operation, and the sludge is collected in the rotary container by the full volume of the rotary container. It is possible to prevent a situation in which centrifugal force exceeding the allowable stress acts and centrifugal breakdown occurs.

Further, collecting sludge more than necessary means that the substantial volume of the container for solid-liquid separation is reduced, which may be a cause of deterioration of separation performance. Therefore, if you monitor the operating state,
It is possible to prevent the above-mentioned harmful effects due to excessive collection of sludge.

The present invention is not limited to the above embodiments. For example, it is possible to install the light receiving element and the light source at separate locations by using an optical fiber, or to make a part of the rotary container mirror-finished to replace the reflecting mirror.

[0035]

According to the present invention, since the amount of sludge collected can be continuously grasped in the operating state of the solid-liquid separator,
It is possible to prevent centrifugal destruction of the rotating container due to excessive collection of sludge. In addition, by measuring the amount of sludge collected, it can be reflected in the process control.

[Brief description of drawings]

FIG. 1 is a first method of detecting the amount of sludge collected according to the present invention.
FIG. 5 is a vertical cross-sectional view showing a solid-liquid separator for explaining the example of FIG.

FIG. 2 is a schematic view partially showing a state when the rotary container in FIG. 1 is stopped and when the rotary container is rotated.

3 is an electric circuit diagram showing a system for transmitting a signal from the strain gauge in FIG.

FIG. 4 is a second method of detecting the amount of sludge collected according to the present invention.
FIG.

5 is a waveform diagram showing the output voltage in FIG.

FIG. 6 is a third method of detecting the amount of sludge collected according to the present invention.
FIG. 3 is a perspective view showing a main part of a rotary container in the embodiment of FIG.

7 is a waveform diagram showing the relationship between the output of the light receiving element that receives the reflected light from the reflecting mirror in FIG. 6 and time.

FIG. 8 is a vertical cross-sectional view showing a rotary container used in a test example of the method for detecting the amount of collected sludge according to the present invention.

9 is a characteristic diagram showing the test results in FIG.

[Explanation of symbols]

1 ... Rotating container, 2 ... Strain gauge, 3 ... Shaft, 4 ... Coupling, 5 ... Motor, 6a, 6b ... Bearing, 7 ... Housing,
8 ... Supply nozzle, 9 ... Washing nozzle, 10 ... Sludge, 11 ...
Bridge circuit, 12 ... Oscillation circuit, 13 ... Chopper circuit, 14 ...
AC amplification circuit, 15 ... Voltage control RF oscillation circuit, 16 ... Buffer amplification circuit, 17 ... Antenna, 18 ... Bridge voltage generation circuit, 19 ... Sensitivity setting device, 20 ... Power supply, 21 ... Sensor, 22 ... Preamplifier, 23 ... FFT Analyzer, 24 ... Control computer, 25 ... DC power supply, 26 ... Reflector, 27 ... Laser light, 28 ...
Reflected light, 29 ... Light receiving element (A, B, C, D).

Claims (4)

[Claims] 1. A method for detecting the amount of sludge trapped, which detects the amount of sludge trapped in a rotary container by using a solid-liquid separator of a type in which a solid component in a liquid is sedimented and removed by utilizing centrifugal force, Measuring the amount of deformation due to the centrifugal force of the rotating container,
A method for detecting the amount of sludge trapped, wherein the weight of sludge trapped inside the rotary container is determined from the comparison between the amount of deformation and a calibration curve created in advance. 2. A strain gauge is attached to the surface of the rotary container, the amount of deformation of the rotary container is detected by the strain gauge, and the detected output is transmitted from a transmitter that rotates integrally with the rotary container to the rotary container. The sludge trapping amount detecting method according to claim 1, wherein the sludge trapping amount is transmitted to a receiver provided outside. 3. The sludge trapping amount detecting method according to claim 1, wherein the amount of deformation of the rotary container is detected by using a non-contact type displacement measuring device utilizing eddy current. 4. A reflecting mirror is attached to the surface of the rotating container, the reflecting mirror is irradiated with laser light, and the amount of deformation of the rotating container is detected from the position and strength of the reflecting mirror. The method for detecting the amount of sludge collected according to claim 1.