JPH0337704Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a laminated type precision filter mainly used as a filter for treating various chemical solutions, pure water, or gas bodies.

(Prior art) Filters for treating chemical liquids and gases used in the production of various pharmaceuticals and electronic parts, as well as pure water used in the food industry, have chemical resistance and heat resistance, and are of submicron order. It is desired to have high filtration accuracy, and recently a filter as shown in FIG. 5A has been widely used to meet this requirement.

That is, the whole desk is made of a chemically and heat resistant synthetic resin such as tetrafluoroethylene, polypropylene, or nylon, and as shown in FIG. A plurality of rows of chevron-shaped protrusions 2a meandering from the boss portion 1a toward the outer peripheral portion 1b are divided by radial grooves 2b, and a meandering protrusion 2a on the upper surface and a protrusion 2a on the lower surface are formed.
The position is shifted in the circumferential direction, and each radial groove 2b communicates with the inside of the central boss portion 1a,
A porous annular thin film filter medium 3 is arranged above and below this circular desk 1, and its outer peripheral edge is welded to the outer peripheral part 1b of the desk 1 to form a desk element.A required number of these desk elements are stacked, and the upper end has an annular upper end plate 4, and a disc-shaped lower end plate 5 at the lower end.
The inner peripheral edge of the thin film filter medium 3 on the top surface of the top desk element is welded to the central lower surface of the upper end plate 4, while the inner peripheral edge of the thin film filter medium 3 on the bottom surface of the bottom desk element is welded to the bottom end. It is welded to the upper surface of the central part of the plate 5, and in other parts, the inner peripheral edge of the thin film filter medium 3 under the upper desk and the inner peripheral edge of the thin film filter medium 3 above the lower desk are welded to each other to form the whole. Then, the upper surface of the center part of the upper end plate 4 is welded to the lower end of the central outlet pipe 7a of the cover 7, and in this state, the laminated element is housed in a pot-shaped container 6, and the lower end plate 5 is attached to the bottom. It is supported by radial ribs 8 provided on the wall, and when in use, the processing fluid is supplied to the container 6 from the inlet pipe 6a at the lower end of the container.
It is introduced into the interior, passed through the thin film filter media 3 of each desk element from the outer periphery, guided inside, and sent out from the outlet pipe 7a of the cover to a desired location.

(Problem to be solved by the invention) By the way, in the laminated filter as described above, when it is used in a fluid circuit or when it is not used, positive pressure (pressure from the outside to the inside) is applied to the thin membrane filter medium 3 of each desk element. ) or reverse pressure (pressure from the inside to the outside) is applied, but in response to positive pressure, the boss portion 1a of each desk element is forced to a certain level through the central thick part of the upper and lower end plates 4 and 5. Since the condition is suppressed, there is no problem with swelling or peeling of the thin membrane filter medium 3 unless the number of laminated layers is small. Since the diameter is smaller than the inner diameter of the container and there is no means to keep the gap constant like the inner circumference, the thin film filter 3 tends to swell as shown in Figure 5C, and the expansion force of the filter 3 causes the upper end plate to collapse. 4 and each desk will curve upward, and as the distance between each desk increases due to the curvature of , the membrane filter medium 3 will expand to that extent, and the welded portion of the membrane filter medium 3 will eventually peel off and become useless. .

In this case, it is conceivable to increase the wall thickness of the end plate 4 and the desk 1, but this would be uneconomical in terms of cost, and the number of stacked layers would decrease, resulting in a decrease in processing capacity.

Therefore, this invention provides a precision filter that can be used for a long period of time without reducing the throughput, without causing the filter material to peel off even if reverse pressure is applied to the thin film filter material.

(Means for solving the problem) Based on the above-mentioned purpose, this invention has a desk element in which thin film filter media are arranged above and below a circular desk with an annular boss section in the center and a flow path in the plate section. As a laminated precision filter, the required number of layers are stacked, a ring-shaped upper end plate is arranged at the upper end, and a disc-shaped lower end plate is arranged at the lower end, and the filter is housed in a container. The present invention is characterized in that the protrusions are provided radially or upwardly, and the protrusions are brought into contact with the inner circumferential portion of the cover to prevent the upper end plate from being held by the cover.

(Example) Figure 1 shows an example of this invention, in which each component is made of synthetic resin with chemical resistance and heat resistance, such as tetrafluoroethylene or polypropylene, and a circular desk 1. On the upper and lower surfaces of the
The chevron-shaped protrusion 2a meandering toward b is the radial groove 2b.
The meandering protrusions 2a on the upper surface and the protrusions 2a on the lower surface are circumferentially shifted in position, and each radial groove 2b is separated by a boss portion 1a.
A porous annular thin membrane filter medium 3 is disposed above and below the circular desk 1, and its outer periphery is welded to the outer periphery of the circular desk 1 to form a desk element. are stacked in a required number of layers, and an annular upper end plate 4 is placed on the upper end of the stack.
A disk-shaped lower end plate 5 is disposed at the lower end, and the inner peripheral edge of the thin film filter medium 3 on the upper surface of the desk at the top is the upper end plate 4.
The inner peripheral edge of the thin film filter material 3 on the lower surface of the bottom desk is welded to the upper surface of the center part of the lower end plate 5, and in the middle, the inner peripheral edge of the thin film filter material 3 under the upper desk and the lower desk The inner peripheral edge of the upper thin film filter medium 3 is welded to each other so that the whole is connected in a bellows shape. The structure is the same as the conventional one in that the upper surface is welded to the lower end of the central outlet pipe 7a of the cover 7.

By the way, in this invention, as shown in FIG. 2, a large number of radial protrusions 4a close to the inner wall surface of the container 6 and inwardly recessed recesses 4b are alternately formed on the outer periphery of the upper end plate 4. , and the inner circumferential edge 7c of the cover 7 which is butted against the upper end opening of the container 6 is brought into contact with each projecting piece 4a, and the upper end plate 4 is restrained by the cover 7.

Therefore, during use, as usual, the processing fluid taken in from the inlet pipe 6a at the lower end of the container is purified by crossing the thin film filter medium 3 of each desk element from the outer periphery, and flows into the inside of the central boss part 1a via the radial groove 2b. Then, it is sent to the required location from the outlet pipe 7a of the cover 7.

At that time, the air contained in the container 6 is pushed upward and passes through the recess 4b provided on the periphery of the upper end plate 4, and passes through the air vent pipe 7b on the cover 7.
released to the outside.

On the other hand, when the apparatus is at rest, a back pressure is applied to the thin film filter medium 3 of each desk element through the outlet pipe 7a connected to the fluid circuit, and the upper end plate 4 attempts to deform each desk 1 and the upper end plate 4 upward. 4
is restrained by the cover 7 via the protruding piece 4a on the peripheral edge, so that upward deformation of the upper end plate 4 and each desk 1 is suppressed, and the gap therebetween is kept almost constant, and the thin film filter medium 3 is prevented from bulging.

In the above example, the circular desk 1 is made into one plate, and the inner circumferential parts of the upper thin film filter medium 3 and the lower thin membrane filter medium 3 are welded to each other. The upper and lower plates of the desk 1 are combined, and a radial groove 2b is formed between the two to form a fluid passage.
The same can be said of a laminated filter in which the boss portions 1a are welded together or connected to the cover with a center pipe, and the inner and outer peripheral edges of the upper and lower thin film filter media 3 are welded to the desk 1. I can do it.

FIGS. 4A and 4B show still another modification example, in which a plurality of protrusions 4a are not provided radially on the outer periphery of the upper end plate 4 but are provided in an upwardly erected manner. The upper end plate 4 is restrained by the cover 7 by bringing the piece 4a into contact with the inner surface of the peripheral edge of the cover 7, and the function of preventing the end plate 4 and the desk 1 from warping is the same as in the above example. In this case, the outer diameter of the upper end plate 4 is slightly smaller than the inner diameter of the container 6, as in the conventional product, so there is no problem with air removal during startup.

(Effect of the invention) As described above, in this invention, as a laminated precision filter, a plurality of protrusions are provided on the outer periphery of the upper end plate to stand up radially and upwardly, and these protrusions are attached to the inner periphery of the cover. Since the upper end plate is restrained by the cover, the upper end plate and each desk are prevented from warping even if a reverse pressure is applied inside the filter when the equipment is stopped, and the end plate is prevented from warping. In addition, the gap between the desks can be kept almost constant, and no strain is applied to the thin membrane filter medium, thereby preventing its bulge and peeling of the welded portion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of this invention. FIG. 2 is a partial perspective view showing the relationship between the upper end plate and the cover. FIG. 3 is a cross-sectional view of a part of the modified example. FIG. 4A is a sectional view of a part of another modification. Figure B is a perspective view of the upper end plate. Figure 5A is a cross-sectional view of the conventional product. Figure B is a partial perspective view of the desk element. Figure C is a partial side view showing the deformed state of the upper end plate and the desk. In the figure, 1...Circular desk, 1a...Boss part, 1
b...outer circumference, 2a...projection, 2b...radial groove, 3...thin membrane filter medium, 4...upper end plate, 4a...
Projection piece, 5...lower end plate, 6...container, 7...cover.

Claims (1)

[Scope of utility model registration request] A required number of desk elements each having thin film filter media 3 disposed above and below a circular desk 1 having an annular boss portion 1a in the center and a flow path in the plate portion are stacked, and an annular upper end plate 4 is placed at the upper end of the desk element. In a filter having a disk-shaped lower end plate 5 disposed at the lower end and housed in a container 6, a plurality of protrusions 4a are erected radially or upwardly on the outer periphery of the upper end plate 4. established,
This is a precision filter in which the protruding piece 4a is brought into contact with the inner periphery of the cover 7 and the upper end plate 4 is restrained by the cover.