JPH01115411A - Device for backwashing filter membrane module - Google Patents

Abstract

PURPOSE:To reduce the excessive clogging and consumption of a filter membrane and to cut down the power cost of the whole device by providing a sensor for sensing the storage amt. of a backwashing cylinder, and varying the storage amt. CONSTITUTION:The backwashing cylinder 26 is provided at the midway of a permeated liq. line 20 for discharging the liq. permeated through the filter membrane 18 in a filter membrane barrel 12, and a float 28 and the sensor 30 for detecting the fact that the storage amt. of the permeated liq. in the cylinder amounts to a specified value are furnished in the cylinder 26. The sensor 30 can be vertically moved, and the variable position of the float 20 corresponding to the position of the sensor, namely the storage amt. of the permeated liq. in the cylinder 26, can be detected. The permeated liq. enters into the cylinder 26 by the start of a pump 16, hence the float 28 is pushed up, and the position of the float 28 is detected by the sensor 30 when the position reaches a specified position. A valve 22 is then opened by a controller 42 to decrease the pressure of the permeated liq. line 20, and the supply of the permeated liq. into the cylinder 26 is stopped. When backwashing is carried out, the valve 22 is closed and a valve 34 is opened by the controller 42, and the permeated liq. is refluxed by the compressed air from a pressurization line 32.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a backwashing device for a filtration membrane module.

(Background of the Invention) A processing liquid is flowed into the filtration membrane under pressure, and the permeate is permeated in a direction perpendicular to the inflow direction (i.e., in the direction of the outer periphery of the filtration membrane) for filtration. There is a so-called cross-flow type filtration membrane module in which components are discharged along the inflow direction and recovered through a treatment liquid circulation line.

In such a filtration membrane module, components to be filtered that have accumulated or become clogged on the inner surface of the filtration membrane are removed by backwashing and returned to the treatment liquid circulation (recovery) line. In other words, a backwash cylinder is provided on the downstream side of the filtration membrane to temporarily store the permeated liquid, and this backwash cylinder causes the permeated liquid to flow back under pressure from the downstream side of the filtration membrane to its upstream side, thereby removing clogging of the filtration membrane. .

Conventionally, the capacity of this backwash cylinder has been constant, and the capacity has been set to be sufficient to remove clogging even when the filtration membrane becomes severely clogged.

However, even if the filtration membrane is not so clogged, storing more permeate than necessary in the backwash cylinder and backflowing this stored liquid under pressure is a must in order to secure enough permeate for backwashing. It is necessary to filter the treatment liquid, which causes the filtration membrane to become clogged and consumes φ, and the power cost also increases.

(Objective of the Invention) The present invention was made in view of the above circumstances, and provides a filtration membrane module that can reduce excessive clogging and wear and tear of the filtration membrane, and further reduce the power cost of the entire device. The purpose is to provide a backwashing device.

(Structure of the Invention) According to the present invention, this purpose is to provide a filtration membrane, a permeate line for taking out the permeate that has passed through the filtration membrane, and a recovery line for recovering the non-filtrate that has not passed through the filtration membrane. A filtration membrane module comprising a backwash cylinder disposed in the middle of the permeate line to temporarily store the permeate and backwash the filtration membrane by pumping the stored liquid from the downstream side of the filtration membrane to the upstream side of the filtration membrane. The backwash cylinder is equipped with a sensor that detects a predetermined amount of stored permeate and stops the flow of permeate into the backwash cylinder, and the amount of permeate stored at which this sensor operates is variable. This is achieved by a backwashing device for the filtration membrane module.

(Example) FIG. 1 is an explanatory diagram of an embodiment of the present invention.

In this figure, reference numeral 10 denotes a processing liquid tank that accommodates a processing liquid;
12 is a cross-flow type filter membrane cylinder for filtering the processing liquid; 14
is a storage tank that stores the permeate.

The processing liquid in the processing liquid tank IO is transferred to the filter membrane cylinder 1 by the pump 16.
The permeate that has passed through the filter membrane 18 in the filter membrane cylinder 12 enters the storage tank 14 via the permeate line 20. 2
2 is a normally open valve provided in the middle of the permeate line. The non-filtrate and non-filtered components that have not passed through the filtration membrane 18 are returned to the treated liquid tank 10 via the recovery line 24.

A permeate line 2 is connected between the filtration membrane 18 and the normally open valve 22.
A backwash cylinder 26 is arranged branching off from 0.

This backwash cylinder 26 has a float 28 floating on the surface of the permeated liquid stored in the internal liquid, and detects that this float 28 is in a predetermined position to detect that the amount of permeated liquid stored in the cylinder has reached a certain level. - Equipped with a sensing sensor 30. The sensor 30 is mounted so as to be movable up and down, and the float 28 position corresponds to its position, that is, the cylinder 2
6 can be variably detected.

32 is a pressurized line that sends pressurized air to the backwash cylinder and causes the stored permeate to flow back under pressure to the upstream side of the filtration membrane 18. 34 is a normally closed valve that opens during backwashing, and 36 is a normally closed valve that opens when storing permeate in the backwash cylinder 26 and releases the pressure applied inside the cylinder 28 to the processing liquid tank 10. Note that 38 is an introduction pipe for introducing the processing liquid into tank 10, and 40 is tank 1.
42 is sensor 3 which detects that the processing liquid in 0 has reached a certain volume and outputs a signal to start operation of the pump 16.
With an output of 0.40, pump 16 and valves 22, 34.
This is a control device that controls the opening and closing of 36.

Next, the operation of this embodiment will be explained.

When the processing liquid in the processing liquid tank 10 reaches a certain volume due to the processing liquid flowing in from the introduction pipe 38, the control device 42 starts the pump 16 in response to an operation start signal from the sensor 40. At this time, at the same time, the valve 22 is closed and the valve 36 is opened. The permeate, which has been force-fed to the filtration membrane cylinder 12 and permeated through the filtration membrane 18, enters the backwash cylinder 26 and pushes up the float 28. When the sensor 30 detects that the cylinder storage amount has reached a predetermined amount and the float 28 has reached a predetermined position, the control device 42 opens the valve 22 based on the output signal of the sensor 30 to lower the pressure in the transmission line 20, and the cylinder The flow of permeate into 26 is stopped. The permeate flows into the reservoir 14 through the permeate line 20 . During this time, the non-filtrate that has not passed through the filtration membrane 18 is returned to the tank 10 via the recovery line 24. When the filtration progresses for a certain period of time according to a timer in the control device 42, the control device 42 closes the valve 22 and opens the valve 34. The float 28 is activated by pressurized air flowing in from the pressurized line 32.
is pushed down, and the stored permeate flows back to the upstream side of the filtration membrane 18.

In this way, clogging on the inner surface of the filtration membrane 18 is removed by backwashing, and solid components are recovered into the tank 10 through the recovery line 24. The backwash time (ie, the time the valve 34 is open) is preset by a timer in the controller 42. After backwashing is completed, close valve 34 while keeping valve 22 closed, and open valve 3.
6 is opened, and the permeate is stored in the backwash cylinder 26 again.

In this way, the permeate is stored in the backwash cylinder 26, filtered,
Filtration is performed while sequentially repeating backwashing.

Here, if the position of the sensor 30 is set low at the beginning of filtration, that is, the amount of storage in the cylinder 26 is reduced, the time required for storage in the cylinder 26, operation, and power costs such as pressurized air supplied to the pressurized line 32 can be reduced. reduction is possible. In addition, the amount of filtration required to secure permeate for backwashing can be reduced.
As a result, there is no need to clog or wear out the filtration membrane.

In this embodiment, by moving the position of the sensor 30, the amount of storage in the cylinder 26 is variably detected and the amount of storage is changed. The control device 42 may determine that the amount has reached a predetermined amount.

Instead of setting the backwashing time with a timer, the amount of liquid collected from the recovery line 24 into the tank 10 by backwashing is measured with the sensor 40, and when the amount of liquid in the tank io increases by the amount stored in the cylinder 26, the backwashing is started. It may be determined that the washing is completed.

(Effects of the Invention) As described above, the present invention is equipped with a sensor that detects the amount of storage in the backwash cylinder, and the amount of storage is made variable. The power cost can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention. 10...processing liquid tank, 12...filtration membrane cylinder, 14...Storage tank, 16...Pump. 18...filtration membrane, 20... Permeate line, 24... Collection line, 26... Backwash cylinder, 30...sensor, 32... pressurized line, 42...Control device. Patent applicant: Shibaura Seisakusho Co., Ltd.

Claims (1)

[Scope of Claims] A filtration membrane, a permeate line for taking out the permeate that has passed through the filtration membrane, a recovery line for recovering the non-filtrate that has not passed through the filtration membrane, and a system disposed in the middle of the permeate line. A filtration membrane module comprising a backwash cylinder that temporarily stores permeated liquid and backwashes the filtration membrane by force-feeding the stored liquid from the downstream side of the filtration membrane to the upstream side of the filtration membrane. A backwashing device for a filtration membrane module, comprising a sensor that detects the amount of permeate and stops the flow of permeate into a backwash cylinder, and the amount of permeate stored at which this sensor operates is variable. .