JPS60166013A - Filtration device - Google Patents

Abstract

PURPOSE:To permit execution of backwashing with a simple device, and to eliminate opportunity of contamination of permeate by pressurizing the permeate side by transmittig the pressure of feed liquid to the permeate side through a stretchable or flexible member in the stage of backwashing of a filter medium. CONSTITUTION:A feed liquid line is separated from a permeate line by a flexible member 6-6, and a volume of permeate corresponding to the volume of deformation of the flexible member 6-6 (i.e. the volume corresponding to the deformation of the flexible member expressed by the dotted line 6-6 from a downwardly convex condition to an upwardly convex condition) flows backward through a filter medium 4-4 to the feed liquid side causing backwashing effect without causing mutual intermixing of the feed liquid and the permeate. And the pressure of the feed liquid serves as the driving force for causing the back flow of the permeate. As a result, the backwashing of the filter medium 4-4 is executed with a simple device and without fear of causing contamination of the permeate by pressurizing the permeate side.

Description

Detailed Description of the Invention (Technical Background) The present invention is a method for backwashing filter media used in filtration devices for filtering various liquids, in which the pressure of the stock solution is transmitted to the permeate side through an elastic or flexible member. The present invention relates to a filtration device characterized by backwashing.

Filtration techniques are used in a variety of fields, ranging from general filtration using filter paper or filter cloth as the filter medium to ultrafiltration using semipermeable membranes and reverse osmosis, but all of these techniques reduce the amount of suspended matter in the liquid after use for a certain period of time. Or the filtration ability decreases due to precipitates from the liquid. This has become the biggest problem in filtration technology, and various methods such as those described below have been taken as countermeasures.

(Prior art and its drawbacks) In all of the above filtration technologies, the filter media used must be replaced eventually, but before this can be done, it is usually necessary to take some measure to restore permeation performance. Common.

For example, a backwashing method in which the permeate is pressurized with a pump and flows back through the filter medium, a chemical washing method in which the slag deposited on the filter medium is dissolved with a chemical, and a scraping or scrubbing method in which the slag is mechanically removed. is well known.

Among these methods, the backwashing method is the simplest and has remarkable permeability and recovery effects, and is therefore widely used.

The conventional backwashing method is a method in which, in addition to the stock solution pressure pump, another pressure pump is installed on the permeate side to flow the permeate or a separately prepared cleaning solution back through the filter medium from the permeate side to the stock solution side. is common.

However, this method of backwashing by separately installing a pressurizing pump is not preferable because the equipment is complicated and the equipment cost increases. In addition, such a method cannot avoid microbial contamination on the permeate side, and may not be adopted depending on the application.

Therefore, the inventor of the present invention conducted extensive research on a method of pressurizing the permeated liquid side using a simple device and without the risk of contamination, and as a result, arrived at the present invention.

(Configuration of the present invention) The configuration of the filtration device according to the present invention will be explained in detail below based on FIG. 1 showing an embodiment.

In FIG. 1, reference numeral 1-1 is a stock solution supply line, and depending on the application, a pressure pump may be installed, or the water pressure of the water supply line may be used as is.

2 to 2 are valves for shutting off liquid supply to the filter element 4-4, 3-3 is a valve for supplying liquid to the flexible member 6-6 in the backwashing process, and 4-4 is a filter A filtration element, which corresponds to a semipermeable membrane module in ultrafiltration, for example.

5-5 is a valve or orifice that is K1-1 open during normal operation, or a valve whose opening degree is appropriately adjusted and fixed, and the flexible member 6-6 is deformed by the filter of the filter element and the pressure of the liquid. A portion of the liquid inside the tank is then drained out through this. 6-6 is a flexible member which may be a diaphragm, a bellows, a bag, etc. or a piston-cylinder.

7-7 is a valve that is open during normal operation, and the permeate from the filtration element 4-4 passes through this valve to the permeate line 10-.
Sent to 10.

8-8 is a pressure regulating valve, an orifice, or a valve whose opening degree is appropriately adjusted and fixed. 9-9 is the concentrate line or drainage of sewage during backwashing, 2-in.

1O-10Fi permeate line; 11-11 is a discharge line for liquid pushed out by the deformation of the flexible member 6-6 (the dotted line in FIG. 1 6-6 is convex downward) during normal operation; If #'; t5-5 is an orifice, it is a line from which a small amount of raw water is always discharged during backwashing.

The key point of the present invention is that the flexible member 6-6 separates the raw liquid line and the permeated liquid line, so that there is no mutual exchange of liquid, and the deformation of the flexible member 6-6 (as shown in FIG. 1, 6-6) A volume of permeated liquid corresponding to the volume of the dotted line deformed from a downwardly convex shape to an upwardly convex shape passes through the filter medium 4-4 and flows back to the stock solution side, resulting in a backwashing effect. The reason is that the pressure on the undiluted solution side can be used as the driving force to reverse the flow.

A concern in the present invention is that the volume corresponding to the deformation of a flexible member such as a diaphragm cannot be made large enough, that is, the amount of backwashing per time is small. However, this problem can be solved by increasing the frequency of backwashing between normal operations, and it has been empirically confirmed that even if the amount of backwashing is small, the cleaning effect is greater if it is performed frequently. Fig. 2 shows the opening/closing pattern for each of the 70 sheets of the device shown in Fig. 1, and shows the switching between normal operation and backwash operation. The time cycle differs depending on the liquid to be treated.

In FIG. 2, the shaded area indicates that the valve is open each time, and only valve 8-8 has a larger opening degree during backwashing than during normal operation.

(Effects of the present invention) When the present invention is applied to a filtration device, the following effects can be obtained compared to conventional methods.

(a) Compared to backwashing using the conventional method, it does not use a pressure pump for backwashing, so it is economically advantageous for equipment.

(b) The mechanical unit becomes more compact, reducing the number of maintenance points.

f9 Since the stock solution side and the permeate side are blocked, 1. There is no microbiological contamination.

[Brief explanation of the drawing]

FIG. 1 shows a 70-sheet filtration device illustrating an embodiment of the present invention. FIG. 2 is a diagram showing the opening and closing patterns during normal operation and backwashing. Takeima Applicant: Daicel Chemical Industries, Ltd.

Claims (1)

[Claims] l) After operation of the filtration device, a part of the filtrate is passed back through the filter material to float contaminants accumulated on the filter material from the surface of the filter material, thereby backwashing the filter material. or both sides of the flexible material simultaneously constitute part of the concentrate passageway and part of the permeate passageway, such that said stretchable or flexible material constitutes part of the concentrate passageway and part of the permeate passageway, such that said stretchable or flexible material constitutes part of the concentrate passageway and part of the permeate passageway; A filtration device characterized by being deformed to the side. 2) The filtration device according to claim 1, wherein the stretchable or flexible member is a diaphragm. 3) The filtration device according to claim 1, wherein the filtration device is an ultrafiltration device.