JPS59228912A - Device for controlling filtration rate of vacuum dehydrator - Google Patents

Abstract

PURPOSE:To dehydrate stably by controlling the number of revolutions of a vacuum dehydrator so that the filtration rate of the vacuum hydrator, calculated from the flow rate of the filtrate of the vacuum dehydrator and the flow rate of the washing water, may be fixed. CONSTITUTION:The flow rates of the filtrate and the washing water are obtained as signals S4 and S5 respectively from flowmeters 4a and 5a, and the filtration rate Rv of the filtrate is obtained as the output from an arithmetic unit 6. The desired revolving speed value N of the drum of a vacuum dehydrator 1 is calculated in accordance with the difference between the reference filtration rate R*v and said filtration rate Rv to fix the filtration rate Rv with a regulator 7. The signal 1a from a speedometer indicating the revolving speed of the drum of the dehydrator 1 and the desired revolving speed N of said drum are used in a regulating 10 to regulate the revolving speed of the drum by controlling the revolution of a motor 1b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the filtration speed of a vacuum dehydrator having a vacuum suction section and an endless f-cloth belt that rotates continuously.

Conventionally, vacuum dehydrators have typically been operated to maintain a constant filtration rate by determining certain operating conditions based on the experience or intuition of facility operators. Therefore, not only is the vacuum dehydrator not operated under optimal operating conditions, but it is also unable to respond to the ever-changing properties of the sludge supplied to the vacuum dehydrator, resulting in the drawback that stable dewatering cannot be performed.

This invention was made in order to eliminate the drawbacks of the prior art as described above, and uses parameters that can be measured relatively easily, such as the flow rate of liquid f in a vacuum dehydrator and the flow rate of washing water, to quickly and accurately measure the Calculate the 1 overspeed of the vacuum dehydrator,
By controlling the rotation speed of the vacuum dehydrator to keep this constant, the aim is to provide a control device that can adequately respond to changes in the properties of supplied sludge that change from moment to moment, and can perform stable dewatering processing. .

An embodiment of the present invention will be described below with reference to the drawings. In the figure, 1 is a vacuum dehydrator, which has a vacuum suction part (not shown), a speedometer lag motor 1b, and an f cloth belt 1C,
A sludge bit 2 is provided below. The sludge bit 2 is supplied with sludge from a pipe 3, and the P liquid resulting from dewatering is guided to a pipe 4. On the other hand, each part of the vacuum dehydrator 1 and f cloth bell) l
Water for washing c is supplied to the vacuum dehydrator 1 through a pipe 5.
is supplied to Flowmeters 4a and 5a are connected to the pipes 4 and 5, respectively, to measure the flow rates, and signals 84 and 85 of the measurement results are input to the calculator 6.

The calculator 6 executes the calculation of equation (1) described below, and inputs the result, a signal S6 indicating the filtration rate Rv, to the controller 7. The controller 1 also inputs a signal 88 for setting the reference filtration speed Rv of the wet cake from the setting sections 8 and 9, and a signal S9 indicating the reference rotation speed increase of the 10-rotation drum of the vacuum dehydrator, which will be explained below (2). The calculation of the equation is executed, and a signal S7 indicating the rotational speed N which is the result is supplied to the controller 10. A speed signal of the rotating drum detected by the speed meter 1a, that is, a signal S1 is input, and a signal 810, which is a drive signal, is supplied to the motor 1b, which is attached to the vacuum dehydrator 1 and rotates it.

Next, the operation will be explained.

The f overspeed RV is the f that occurs per unit area per unit time.
Regarding the amount of liquid, in the actual facility, there is also washing water used for washing the P cloth belt 1c and the vacuum dehydrator 1, so the calculator 6 calculates the following equation.

Rv=(Qo-Qw)/A a (1) where, Rv: ip filtration rate Qo: flow rate of P liquid, QW: flow rate of washing water, A: filtration area.

In the present invention, Q. , QW are obtained as signals s4 and s5 of the flowmeters 4a and 5a, respectively, and Rv is obtained as the output of the calculator 6. In order to keep the f overspeed Rv constant, the regulator 1 calculates the following equation according to the difference between the reference filtration speed Rv and the measured filtration speed Rv.

N = N 10G (Rv-Rv) ... (2)
Here, G is the gain of the controller 7, N is the rotation speed N set with the manual setting device 9, N is the target value of the drum rotation speed of the vacuum dehydrator 1, and N is the target value of the drum rotation speed of the vacuum dehydrator 1. be. The controller 10 uses signals 1a and N from the speedometer indicating the drum rotation speed of the vacuum dehydrator 1 to adjust the rotation speed of the drum by controlling the rotation of the motor 1b.

In the above embodiments, the circuits are constructed with analog circuits, but the same effects as in the above embodiments can be obtained even if the circuits are constructed with time-discontinuous analog (sampling) or digital circuits.

As described above, according to the present invention, the filtration rate of the vacuum dehydrator can be quickly and accurately calculated using relatively easily measurable factors such as the flow rate of the dehydrated P liquid and the flow rate of the washing water.
Since the rotational speed of the vacuum dehydrator is controlled to keep this constant, it is possible to sufficiently respond to changes in the properties of the supplied sludge, which change from moment to moment, and to perform stable dehydration processing.

[Brief explanation of the drawing]

The figure is a block diagram of an f-overspeed control device for a vacuum dehydrator according to an embodiment of the present invention. 1...Vacuum dehydrator, 2...Sludge bit, 3,4.5
... Pipe line, 6... Arithmetic unit, 7.10... Controller,
8, 9... Setting device 1a... Speedometer, 1b... Motor, 1C... P cloth belt, 4a, 5a... Flow meter.

Claims (1)

[Claims] In a filtration speed control device for a vacuum dehydrator that controls the filtration speed of a vacuum dehydrator that dehydrates sludge through a fed sludge cloth belt, the P liquid discharged from the vacuum dehydrator and the vacuum dehydrator are washed. From each flow rate of washing water for
an arithmetic circuit that calculates the filtration speed of the liquid; a controller that outputs a rotational speed signal according to the difference between a preset reference overspeed and the filtration speed of the arithmetic circuit calculated by the arithmetic circuit; A filtration speed control device for a vacuum dehydrator, comprising: a drive section that adjusts the rotation speed of a motor that drives the vacuum dehydrator according to the rotation speed signal of a controller.