JPS59228911A - 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 wet cake, calculted from the flow rate of the sludge to be supplied to the dehydrator, the flow rate of the filtrate from the dehydrator, and the flow rate of the washing water, may be fixed. CONSTITUTION:The flow rates of the supply sludge, the filtrate, and the washing water are obtained respectively from flowmeters 3a, 4a, and 5a, and the filtration rate Rw of the wet cake is calculted by an arithmetic unit 6. Since the revolving speed of the drum of a vacuum dehydrator 1, i.e. that of a motor 1b, is regulated in accordance with the difference between a signal S8, which is the reference filtration rate R*w, and the signal S6 which is said Rw to control and fix the filtration rate Rw of the wet cake with a regulator 7, the desired revolving speed value N of the drum of the dehydrator 1 is calculated. In addition, the revolving speed of the drum is regulated with a regulator 10 by using the signal S1 from a speedometer 1a of the dehydrator 1 and the signal S7 from the regulator 7, and regulating the motor 1b for driving the drum of the dehydrator 1 through the signal S10.

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 furnace cloth belt that rotates continuously.

Conventionally, the filtration speed of a vacuum dehydrator has usually been determined under certain operating conditions based on the experience or intuition of the operator. For this reason, not only is the system not operated under optimal operating conditions, it is also unable to respond to the ever-changing properties of the sludge supplied to the dehydrator, resulting in the drawback that stable dewatering cannot be performed.

This invention was made in order to eliminate the drawbacks of the conventional operating method as described above, and it is possible to relatively easily measure the flow rate of sludge supplied to the dehydrator, the flow rate of P liquid in the dehydrator, and the flow rate of washing water. By quickly and accurately calculating the filtration rate of the wet cake in the vacuum dehydrator using a device and controlling the rotation speed of the vacuum dehydrator to keep it constant, the The purpose is to provide a control device that can sufficiently respond to changes and perform stable dehydration 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 includes a vacuum suction section (not shown), a speedometer 1a, a motor 1b, and a P cloth belt 1C.
A sludge pit 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, water for washing each part of the vacuum dehydrator 1 including the p-cloth belt 1C is supplied to the vacuum dehydrator 1 through a pipe 5.
supplied to Lines 3.4 and 5 each have a flow meter 3.
a, 4a, and 5a are connected to measure the flow rate, and the measurement result signals S3, s4, and s5 are input to the calculator 6.

The calculator 6 executes the calculation of equation (1) described below, and inputs the resulting signal S6 to the controller 7. The controller 7 also inputs a signal S8 for setting the filtration speed of the wet cake from the setting meters 8 and 9 and a signal S9 indicating the reference value of the drum rotation speed of the dehydrator 1, and calculates the equation (2) described below. The resultant signal S7 is supplied to the controller 10. The controller 10 is attached to the vacuum dehydrator 1, and receives a speed signal, that is, a signal S1, from a speedometer 1a that measures the rotation speed of the controller 10, and is attached to the vacuum dehydrator 1 and is driven by a motor 1b that rotates it. A signal 810 is provided.

Next, the operation will be explained. Wet cake overspeed is
It is the amount of wet cake generated per unit area in unit time, and is indicated by the difference between the amount of supplied sludge and the amount of P liquid. Therefore, the calculator 6 calculates the following equation.

Rw=(Qi-Qo+Qw)/A number of songs - (1)
Here, RW: Transient rate of wet cake Qi: Flow rate of supplied sludge Qo: Flow rate of F liquid QW: Flow rate of washing water A: Filtration area In the case of the present invention, Qi% QO% Qw is the flowmeter 3as4a and 5a, respectively are obtained as signals S3, S4 and S5. The filtration rate 1 (w is outputted from this as a signal S8. The controller 7 controls the filtration rate between the reference filtration rate signal S8 and the detected filtration rate signal S6 in order to control the filtration rate of the wet cake constant. In order to adjust the rotational speed of the drum beating motor 1b of the dehydrator 1 according to the difference, the following equation is calculated.

N=N"10G(l(w-RW)...
(2) Here, Rw" is the reference filtration speed set by the setting device 8, that is, the signal S8, G is the gain of the controller 7, and N is the target value of the rotation speed of the drum of the vacuum dehydrator 1. This is the signal S7 to the controller 10. N'' is the reference rotational speed of the drum of the vacuum dehydrator 1, that is, the signal S9. The controller 10 uses the signal S1 of the speedometer 1a of the vacuum dehydrator 1 and the signal S7 of the controller 7, and adjusts the motor 1b that drives the drum of the vacuum dehydrator 1 using the signal S10.
Adjust the rotation speed of the drum.

In addition, although the circuit in the above embodiment was configured with an analog circuit,
The same effects as in the above embodiments can be obtained even if a time-discontinuous analog type (sampling type) or digital type circuit is used.

As described above, according to the present invention, the wet cake of a vacuum dehydrator can be filtered quickly and accurately using relatively easily measured flow rates such as the flow rate of supplied sludge, the flow rate of dehydrated P liquid, and the flow rate of washing water. Calculate the speed and keep it constant22. Since the rotation speed of the sea urchin vacuum dehydrator is controlled, it is able to cope with the constantly changing properties of the supplied sludge.
It has an extremely excellent effect of being able to perform stable dehydration treatment.

[Brief explanation of the drawing]

The figure is a block diagram of an offshore overspeed control device for a vacuum dehydrator according to an embodiment of the present invention. 1...Vacuum dehydrator, 2...Sludge pick), 3,4
゜5... Pipeline, 6... Arithmetic unit, 7... Controller, 8.9... Setting device, 1a... Speed meter,
1b...motor, 1c...furnace belt,
3a, 4a, '5a...Flowmeter. Agent □ (name of Riki) 312-1-1, Omori Honmachi-chome, Ota-ku, Tokyo ■Applicant Mitsubishi Electric Corporation 2-2-3 Marunouchi, Chiyoda-ku, Tokyo

Claims (1)

[Claims] In a filtration speed control device for a vacuum dehydrator having a vacuum suction section and a continuously rotating endless P cloth belt, the flow rate of sludge supplied to the dehydrator, the flow rate of its F liquid, and cleaning for cleaning the vacuum dehydrator are provided. A flowmeter that measures the flow rate of water, an arithmetic circuit that calculates the filtration rate of the wet cake of the vacuum dehydrator based on the output of each of the flowmeters, and a preset filtration rate calculated by the arithmetic circuit. A first controller that generates an output according to the difference from the reference filtration speed, and a second controller that adjusts the rotation speed of the motor that drives the vacuum dehydrator according to the output of the first controller. Vacuum dehydrator filtration speed control device.