JPS62140612A - Method for operating filter device - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the filtration performance of the titled device and to easily cope with the situation even when plural filters are used by zeroing the flow rate of raw water when the flow rate of raw water passing through the filter is lower than the flow rate necessary for retaining a precoat layer on an element. CONSTITUTION:The sum of the flow rate QM of a main pump 37 and the flow rate QA of a retaining pump 35 is calculated. A controller 42 for outputting an abnormal retention signal when the sum becomes lower than the specified flow rate QS necessary for retaining the precoat layer, namely QM+QA<QS, is provided. The conditions where the precoat layer formed on the element provided to a filter 31 is stripped are detected, and the flow rate of raw water passing through the filter is zeroed. Consequently, the curling up of a clad along with the fallen precoat material and the deposition of the clad on the element can be prevented. Even when the plural filters are used, only the filter concerned is stopped, and the situation can be easily coped with.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of operating a filtration treatment apparatus that performs filtration using a precoat layer.

[Prior art]

In a precoat type filtration treatment device that uses a filter with a precoat layer formed on the element, the flow rate of raw water such as boiler condensate that passes through the precoat layer ( In other words, the flow rate) is given a predetermined flow rate (this is called a holding flow rate) required to hold the precoat layer. Therefore, in preparation for the standby process when the filtration work is stopped, a holding pump is installed as an auxiliary pump in parallel with the filter, in addition to the main pump, and a holding bomb is used to back up the specified holding flow rate during the standby process. The precoat layer is retained. In the water sampling process (filtration process), the main pump is operated to allow raw water to pass through the filter at a flow rate higher than the retention flow rate, to collect and remove crud for filtration, and to maintain the precoat layer. If the flow rate of the main pump falls below the holding flow rate during the water sampling process, the holding pump is activated to perform bank up.

[Problem that the invention seeks to solve]

However, in such pre-coated filters, when the passing flow rate is less than the holding flow rate, the pre-coat layer peels off, and when the fallen pre-coat material rolls up mixed with kraft, crud also adheres to the element. However, there is a problem in that it prevents the pre-coating material from adhering, making it impossible to perform normal filtration work.

Furthermore, in systems using such filtration processing equipment, multiple filters are often used in parallel, so for multiple filters! It was difficult for workers to take measures against Fi11 separation by hand.

The present invention solves the above-mentioned problems of the conventional method, detects the condition where the pre-coat layer peels off, reduces the flow rate of raw water passing through the filter to zero, and causes the craft to roll up along with the fallen pre-coat material. We are committed to providing an operating method for filtration equipment that can prevent the water from rising and adhering to the element, and even if there are multiple filters, only that filter can be stopped to easily deal with the problem. It is something to do.

[Means for solving problems]

As a means for solving the above-mentioned problems of the conventional methods, the present invention provides a method for operating a filtration treatment device in which raw water is filtered through a filter equipped with an element on which a precoat layer is formed, in which raw water passes through the filter. A method for operating a filtration treatment device, characterized in that the flow rate of raw water passing through the filter is set to zero when the flow rate is less than a predetermined flow rate necessary to hold the precoat layer in the element. We aim to provide the following.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a flow diagram of the filtration processing apparatus, in which 31 is a precoat type filter equipped with an element in which a precoat layer is formed, 32 is an outlet valve, 33 is an inlet valve, 34 is an inlet bypass valve, and 35 is a A holding pump as a backup auxiliary pump arranged in parallel with the filter 31, 36 a discharge valve of the holding pump, 37 a main pump, 38 a strainer,
39 is a flow rate control valve, 40 is a flow 11m moderator, and 41 is a flow rate detector.

42 is the flow fiQ of the main pump 37. and holding pump flow ff
i Q Calculate the sum of A, and when the value of the sum becomes smaller than the predetermined flow WQs necessary to hold the precoat layer, that is, Q, 4 + QA × Q, a holding abnormal signal is generated. It is a control device.

A block diagram of the operation of such a filtration system for protecting the precoat layer is shown in FIG.

In FIG. 2, the water sampling output signal 6, the water sampling start output signal 7, and the standby output signal 8 are input to the OR circuit 4, and the OR circuit 4
The output signal 13 of and the holding abnormal signal 11 are input to the OR circuit 4, and the output signal 13 is input to the holding pump stop circuit 20, the holding pump discharge valve fully closed circuit 21, the filtration processing device outlet valve fully closed circuit 22, and the filtration processing device artificial valve fully closed. Inputted into the circuit 23, signals indicating that the command has been reliably executed are a holding pump stop signal 15, a holding pump discharge valve fully closed 13, 16, a filtration processing device output valve fully closed signal 17, and a filtration processing device artificial valve fully closed signal 18. , filtration processing bag universal bypass valve full close signal 19A
The ND circuit 2 is manually powered, and its output signal 24 is input to the mechanical self-holding circuits 5 and 25.

The output signal 14 of the mechanical self-holding circuit 5 is input to the resent side of the electrical self-holding circuit 3.

On the other hand, the output signal 12 of the electric self-holding circuit 3 is used as the system disconnection output signal 26, which instructs the filtration processing device inlet bypass valve to be fully closed, and outputs the sampling output signal 6, the water sampling start output signal 7, or the standby output signal. It is input to the reset signal of 8.

The operation will be explained.

First, the operation in the standby state will be explained.

In the standby state, the large mouth valve 33 and the outlet valve 32 are closed, the discharge valve 36 is opened, the holding pump 35 is operated, and the filter 31 receives a circulation flow (flow rate Q) by the holding pump 35.
a) is flowing. The large mouth bypass valve 34 is connected to the main pump 3
7, it is closed only when stopped, and is always open at other times. By setting the constant time in this way, when the large mouth valve 33 is closed in the standby state, the temperature of the Va recirculation passing through the filter 31 by the holding pump 35 is prevented from gradually rising and the internal pressure is prevented from increasing. It has become.

During standby operation, the flow rate Q is reduced to maintain the precoat layer.
A is selected such that QA≧Q.

During such standby operation, the flow rate QA is detected by the flow rate detector 41.
is detected, and when Q<Q, a holding abnormal signal 11 is generated, which is passed through the OR circuit 4, and the output signal 13 is sent to the holding pump stop circuit 20, the holding pump discharge valve fully closed circuit 21, The filtration processing device outlet valve fully closed circuit 22, the filtration processing device artificial valve fully closed circuit 23 are manually operated, the holding pump stop signal 15, the holding pump discharge valve fully open signal 16, the filtration processing device outlet valve fully open signal 17, the filtration processing device Population valve fully closed signal 1
8, the flow rate of raw water passing through the filter 31 is set to zero, and the filter 1 is cut off and isolated from other systems.

When multiple filters are installed in parallel, each filter is provided with a parallel holding pump line, an outlet valve, and a large mouth valve, so that the raw water IQ Ax passing through the filter is If the flow rate becomes smaller than 1JFos required to retain the precoat layer, stop or close only the retention pump, retention pump discharge valve, outlet valve, and large mouth valve attached to the filter, and remove the filter. Separate and isolate from other filter systems and other systems.

The inlet bypass valve 34 is open during normal standby operation, but when the holding abnormality signal 11 is established, the sampling output signal 6, the water sampling start output signal 7, or the standby output signal 8 is activated.
is reset, and the inlet bypass valve 34 is fully closed.

If the flow rate of raw water inside the filter 31 becomes zero, the precoat material will fall and the precoat layer will no longer be retained.
It is possible to prevent the cladding from rolling up and adhering to the element.

The isolated filter 1 is quickly backwashed and a new precoat layer is formed. At this time, the mechanical self-holding circuit 5 is reset by the backwashing start signal 27, and the backwashing completion signal 2
8, the mechanical self-holding circuit 25 is reset.

Next, operations during sampling or process transition will be explained.

During sampling or process transition, the main pump 37 is controlled separately from the main filtration processing device, and when the flow ff1a becomes Q,<QS, the holding pump 35 is operated in a bank-up manner so that Q,+QA≧ Q.

Thus, the precoat layer is retained.

In the control device 42, Q is always present. and QA and sum, QM
+QA<Q.

When this happens, the holding abnormality signal 11 is issued, and in the same way as in the standby state described above, the flow rate of raw water flowing through the filter 1 is set to zero, and the filter 1 is cut off from other systems. to prevent the cladding from rolling up and adhering to the element.

In addition, with the control bag ff42, Q, +QA<Q.

If it is determined that this is the case, a light or sound alarm will be issued, and this alarm will cause the user to manually push the system disconnection push button switch 1 and send a signal to the OR circuit 4 via the AND circuit 2 and the electric self-holding circuit 3. Give and hold abnormal signal 11
The same operation may be performed if .

In the case of a filtration device that does not use the holding pump 35 and is equipped with only the main pump 37, when the flow rates o and I of the main pump 37 become QM<Qs, the holding abnormal signal 11 is issued, or the system disconnection push button is pressed. All you have to do is press switch 1 to give a signal to the OR circuit 1 and perform the same operation as the previous IF.

〔Effect of the invention〕

According to the present invention, it is possible to prevent the crud from rolling up during G when the precoat layer is peeled off in a precoat type filtration treatment device, to prevent filtration caused by a defective element to which the crud is attached, to prevent deterioration of filtration performance, and to improve reliability. It is possible to provide a method for operating a filtration treatment device that is easy to operate even in a device that is large in size and has a plurality of filters, and has extremely great practical effects.

[Brief explanation of drawings]

FIG. 1 is a flow diagram of an embodiment of the present invention, and FIG. 2 is a block circuit diagram of its control system. 1... System disconnection push button switch, 2... A
ND circuit, 3...Electric self-holding circuit, 4...OR
Circuit, 5... Mechanical self-holding circuit, 6... Output signal during sampling, 7... Water sampling start output signal, 8... Standby output signal, 9.10... Output signal, 11. ...Holding abnormal signal, 12゜13.14... Output signal, 15... Holding pump stop signal, 16... Holding pump discharge valve fully closed signal, 17... Filtration processing device outlet valve fully closed signal , 18...
Filtration processing device population valve fully closed signal, 19... Filtration processing bag entry bypass valve fully closed signal, 20... Holding pump stop circuit, 21... Holding pump discharge valve fully closed circuit, 22...
Filtration processing device outlet valve fully closed circuit, 23... Filtration processing device artificial valve fully closed circuit, 24... Output signal, 25... Mechanical self-holding circuit, 26... System disconnection output signal, 2
7... Backwash start signal, 28... Backwash completion signal.

Claims (1)

[Scope of Claims] 1. A method of operating a filtration treatment device for filtering raw water using a filter equipped with an element on which a precoat layer is formed, wherein the flow rate of raw water passing through the filter is such that the flow rate of the raw water passing through the filter causes the precoat layer to be formed on the element. 1. A method for operating a filtration device, characterized in that the flow rate of raw water passing through the filter is set to zero when the flow rate is less than a predetermined flow rate required to maintain the flow rate. 2. A filtration treatment device that filters raw water through a filter equipped with an element on which a precoat layer is formed, in addition to a main pump that supplies the raw water, the filter is installed in parallel with the filter, and the water passing through the filter is In the method for operating a filtration treatment apparatus equipped with an auxiliary pump that backs up the flow rate, when the main pump stops and the auxiliary pump performs backup operation, the discharge flow rate of the auxiliary pump increases when the precoat is applied to the element. 1. A method for operating a filtration device, characterized in that the flow rate of raw water passing through the filter is set to zero when the flow rate is less than a predetermined flow rate required to maintain the layer.