JPS5962323A - Built-up type precision filter unit - Google Patents

Abstract

PURPOSE:To provide a titled filter unit which is extremely highly resistant to chemicals, acids, etc. as adhesive agents contg. metals and solvents, etc. are not used by welding thermally a porous thin film filter medium consisting of tetrafluoroethylene on the surface of a support produced by building up approximately plate-like support plates consisting of a copolymer of tetrafluoroethylene. CONSTITUTION:This built-up type precision filter unit 20 consists of a supporting plate 22 formed by superposing two sheets of supporting plates 21 21' consisting of a tetrafluoroethylene copolymer (FEP, PFA or ETFE). Porous annular film filter media 23, 23' of a polytetrafluoroethylene (PTFE) are thermally welded to the surface of the plate 22 thereby forming the unit 20. The plates 21, 21' have bosses 24, 24' projecting from the built-up rear surface to the front surface side, and are perforated with through-holes 25, 25' in the central part thereof. Network parts 26, 26' are provided like a disc around the bosses 24, 24' and many openings 27, 27' are perforated like network. The unit 20 is used as the filter unit produced by building up a prescribed number of stages of such units, sealing the end faces of the butted bosses by thermal welding, and closing the one end of the communicated through-holes.

Description

[Detailed description of the invention] The present invention relates to a laminated precision filter unit.

The filter element of the product fF'r type precision filter is
Two first supporting plates, which are plate-shaped and have a through hole in the center and a mesh part with many openings around them, are stacked one on top of the other to form a support, and this surface is covered with an Ill-shaped P material to form a filter. Units are stacked in an appropriate number of stages, and one end of the central through hole is closed. As shown in FIG. 1, a conventional filter unit 1 has two stainless steel support plates 2.2' each having a through hole 3.3' in the center and a mesh portion 4.4' having numerous openings around the through hole 3.3'. The mesh portions 4, 4' openings and through holes 3.3' are made to communicate with each other through grooves 5.5' formed on the mating surfaces, and the mesh portions 4.4' are made of polytetrafluoroethylene (PTFE). ) covered with porous thin film furnace material 6.6'. In the filter unit 7 for precision application, if the joints of the support plate are exposed outside the appropriate material, leakage will occur, causing problems, and the metal and furnace material cannot be welded, so the furnace material 6.6 ' is filtered outward from the outer periphery of the support plate 2.2' and its peripheral edge 7 is welded in the form of a bag.
) Since it is difficult to heat weld the two pieces together, it is necessary to use tetrafluoroethylene copolymer (FEP, PFA or ETFE) between the furnace materials 6.6'.
) are sandwiched and heat-pressed. When such filter units 1 are stacked, the packing 10 is sandwiched and tightened, but due to creep, tightening, loosening, etc. of the packing material, it is not possible to maintain a sealing performance suitable for precision offshore passing. For this reason, it is desirable to have a filter element that separates the contaminated side before the offshore passage and the clean side after the offshore passage, not only by mechanical methods such as tightening the gasket, but also by welding. . Moreover, the t-liquid is, for example, a cleaning liquid used in the production of LSIs and ICs, and 1li111.
Since it is often used as an acid solution for engraving, it is necessary that the solution does not contain metals or solvents. Therefore, materials melted using solvents, adhesives, etc. are not suitable, and the filter element must be limited to acids, solvents, and other chemicals, as well as stable ethylene and its copolymers. The filter element must be formed by molding and welding the above materials without using solvents or the like. However, ethylene tetrafluoride (PTFF) cannot be melt-molded, and cannot be welded using a solvent.

Invention 1: J A FI or ETF to solve the above-mentioned problems and perform off-shore fishing suitable for the above-mentioned purpose of use.
We present a filter unino) in which a porous tetrafluoroethylene membrane (pH) is directly thermally welded to the support plate. - to do.

To explain this invention with reference to an embodiment, in FIG. 2, a laminated precision filter unit 20 is ethylene tetrafluoride.
Two support plates 21 and 21' made of polymer (FEP, PFA or ETFE) are stacked together to form a support 22,
A porous annular membrane ρ material 23, 23' made of tetrafluoroethylene (PTFE) is welded to its surface.

The support $1721.21' has a boss part 24.24' that protrudes from the back side to the front side where the shields are screwed together, and the central part thereof has a TNT A hole 2! 'i, 25'7□ (Drilled sawtail. Host part 24.24') Disk-shaped mesh part 26.2 around
6', a large number of openings 27, 27' are bored in a mesh pattern.

A groove 28, 28' is provided in the overlapping surface of the back of the support plate, and by kneading, an opening 27, 27' and a through hole 25, 25 are formed.
' are connected. The outer side of the mesh part 26, 26' becomes two outer frame parts 29', and the outer frame part 29' of the support plate 21' fits inside the outer frame part 29 of the support plate 21, and its surface is the same. combined to form a flat surface. Support plate 23.23'
A desired shape can be obtained by melt molding.

In the annular furnace material 23, the inner peripheral edge of the mesh part 26 is thermally welded to the outer frame part 29 at the outer peripheral edge. Also, Okizai 23'
The inner peripheral edge is heat-welded to the inside of the mesh portion 26', and the outer peripheral edge covers the outer frame 29' of the support body 21' and is attached to the four parts of the support plate 21.
It is thermally welded to the frame 29. For heat welding, the support is made of four ethylene copolymers (CFEP, P:FA or FTFE).
Therefore, when the furnace belly and the support are brought into direct contact (1) and heated, the support material has fluidity and penetrates into the structure of the porous furnace belly, and is bonded and welded by the entanglement projection effect. It is something that

The laminated precision filter unit as described above is used as a filter unit by laminating the layers according to the required design, heat-sealing the end faces of the butting boss parts by heat and welding, and closing one end of the communicating through hole. The J5 liquid (or gas) that entered from the outside of the reactor belly and passed through the mesh opening, the internal passage on the back of the support plate, and the central through hole should be guided to the required 1M location.

The above-described laminated precision filter unit according to the present invention is made of tetrafluoroethylene and its copolymer, and because it does not use adhesives containing metals or solvents, it has excellent chemical resistance, acid resistance, etc. 5+・It is carefully designed and suitable for the purpose of use mentioned above, and by melting and forming the support plate, the seam of the support plate (JJ plate) can be moved inside the furnace material welded to the surface of the support plate. It is possible to save unnecessary fj materials such as covering the outer peripheral edge of the ρ material with a support plate and welding it together, or providing a space for pressing the seal on the inner peripheral edge.In addition, there is no need to sandwich the material for welding between the offshore material and the support. Instead of direct welding, the seal can be removed and welded, and the production process is more efficient.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional laminated precision filter unit. FIG. 2 is a sectional view of the laminated precision filter unit of the present invention.

Claims (1)

[Claims] A porous thin film furnace material made of tetrafluoroethylene (PTFE) is thermally welded to the surface of a support made of superimposed nearly plate-shaped support plates made of FEP, PFA, or ETFE, which are copolymers of tetrafluoroethylene. Laminated precision filter unit.