GB2071721A - Improved filter pleat spacing process - Google Patents
Improved filter pleat spacing process Download PDFInfo
- Publication number
- GB2071721A GB2071721A GB8100786A GB8100786A GB2071721A GB 2071721 A GB2071721 A GB 2071721A GB 8100786 A GB8100786 A GB 8100786A GB 8100786 A GB8100786 A GB 8100786A GB 2071721 A GB2071721 A GB 2071721A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pleats
- filter material
- filter
- folds
- strip
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims description 16
- 239000000463 material Substances 0.000 claims abstract description 53
- 239000004115 Sodium Silicate Substances 0.000 claims abstract description 5
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910052911 sodium silicate Inorganic materials 0.000 claims abstract description 5
- 238000004519 manufacturing process Methods 0.000 claims abstract 3
- 230000000452 restraining effect Effects 0.000 claims abstract 2
- 238000010924 continuous production Methods 0.000 claims 1
- 230000005855 radiation Effects 0.000 abstract description 2
- 239000003292 glue Substances 0.000 description 10
- 239000003365 glass fiber Substances 0.000 description 4
- 235000011837 pasties Nutrition 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 229920001410 Microfiber Polymers 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 239000003658 microfiber Substances 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/52—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material
- B01D46/521—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material
- B01D46/523—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material with means for maintaining spacing between the pleats or folds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/01—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements
- B01D29/012—Making filtering elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/01—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements
- B01D29/05—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements supported
- B01D29/07—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements supported with corrugated, folded or wound filtering sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/0001—Making filtering elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/10—Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
- B31F1/00—Mechanical deformation without removing material, e.g. in combination with laminating
- B31F1/20—Corrugating; Corrugating combined with laminating to other layers
- B31F1/32—Corrugating already corrugated webs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2265/00—Casings, housings or mounting for filters specially adapted for separating dispersed particles from gases or vapours
- B01D2265/04—Permanent measures for connecting different parts of the filter, e.g. welding, glueing or moulding
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Filtering Materials (AREA)
Abstract
In the manufacture of pleated filters with concertina folds a strip of additional material 5 is folded in with the filter material 6 as the pleats are formed in a conventional folding machine. The bulk and resilience of the additional strip 5 tend to open out the pleats and restraining means 10, 11 limit this so as to obtain pleats opened to a desired extent. The pleats are then to be held in place by the application to the crests of the pleats of a curable material such as sodium silicate. This may be applied to both sides of the filter material to obtain a relatively inflexible filter, or to one side only to obtain a filter which may be fitted around a cylinder. The curable material may be cured by infrared radiation. <IMAGE>
Description
SPECIFICATION
Improved filter pleat spacing process
This invention relates to the formation of pleated filter elements and in particular is concerned with the spacing and locking of the pleats in the filter material.
The prior art in this field describes several ways of locking and spacing filter element pleats. In his
U.K. Patent 1277588 Marshall describes the application of lines or blobs of glue before folding to form pleats subsequently held together by contact between the lines of glue on adjacent pleat panels. The spacing between panels is thus determined by the thickness of the lines or blobs of glue. U.K. Patent 1408194 describes the application of strips of pasty and hardenable material to be prefolded and opened out filter paper such that when refolded, adjacent strips of pasty and hardenable material adhere to one another thus defining the gap between adjacent pleat panels and, on hardening, locking them in that position.One problem which would occur here is, if the folded filter element be flexed beyond a critical yield point of the now hardened pastes, such hardened pastes will break due to lack of ductility and by reason of their adhesion to the substrate will weaken tear or rupture the filter media creating leakage of unfiltered air. U.K.
Patent 1221310 describes a filter comprising zig zag folds of pleated filter element wherein spacer strips are used to space the pleats and further material strips placed in contact with the pleat crests, are used to hold the pleat together.
Unlike U.K. Patent 1221310, the invention provides for the self spacing of the filter element pleats without the use of strips whose physical dimensions determine the spacing between pleat panels. The self spacing is achieved by controlled partial opening of the tightly packed folds from the folding machine by use, for example of brake strips or other suitable means. The strips folded with the filter material provide an opening force to the tightly packed folds, by reason of their bulk between the folds and their natural resilience.
Furthermore the resilient strips of material folded with the filter element also provide strengthening means for the element and an advantageous site for the placement of curable material, which together with the strips locks the pleats in position. It is thus easier to produce filters with "open" pleats than heretofore. Such filters with "open" pleats have adjacent pleat panels at a greater angle to each other than those spaced and locked by adjacent self-adhering strips of glue. The use of previously applied lines of glue with deformable cores to define and lock the folds in position after folding to produce "open pleated" filter elements is thus rendered unnecessary.
Another advantage inherent in the invention arises from the locking means being applied after pleat folding and spacing. In the prior art where lines of glue or pasty hardenable material had been used it was applied before the final folding operation. This had the disadvantage of requiring the folds to be made with lines of glue in situ thus requiring additional prefolds and opening out operations prior to glue application and the final folding for optimum operation, which process could lead to damage of the filter material. The present invention may also reduce the tendency of the filter material to tear if the element is flexed beyond the critical yield point of the glue of pasty material since any adhesive material need contact only the strips, and not the filter material itself.By the invention herein described the folding of the paper with glue in situ is avoided and only one folding operation is required. The filtering media to be so folded, spaced and locked can be made of any of a number of different materials. For example glass microfibre (HEPA) paper, resin impregnated cellulose paper, blended cellulose and glass fibre paper or semi rigid woven and nonwoven cloths and felts manufactured from manmade or natural fibres. Another aspect of the invention includes apparatus for carrying out the process described above.
A particular embodiment of the invention will now be described with reference to the accompanying drawings, wherein:~
Fig. 1 is a side view of apparatus for folding filter elements;
Fig. 2 is a side view of apparatus for applying to the filter elements and curing a curable material; and
Fig. 3 is a side view of a portion of a finished filter element.
In Fig. a feeder roll 3 supplies filter media 6 directly to a proprietary folding machine. Feeder roll 2 supplies material to a slitting device 4 which cuts the material into a plurality of strips. The material supplied by feeder roll 2 is the same as that of the filter media 6 in the preferred embodiment, though any other suitable material may be used. The trips 5 thus formed are controlled by guides to the upper and under sides of the substate filter media 6 and are then folded simultaneously with it in the commercially available folding machine 1. The folding machine 1 produces a tightly compressed pack of folds 7.
This pack of folds breaks out from the counter pressure device 8 which is important in controlling the initial folding part of the process. The adjacent folds 12 now space themselves to a degree controlled by the resilience of the strips 5 and the substrate filter media 6 by an opening ramp 9 and by restraint from the pack release brake strips 10 and a resistance block 11 or other suitable means.
The process continues allowing the folded and spaced substrate filter media 12 to pass into a suitable shuttle frame 1 3 until it is filled with a predetermined number of folds. At this stage cutting devices 14 and 15 are used to sever the folded and spaced substrate filter media, the end of the frame 13 is then closed at 20, and it is removed together with the filter media and an empty shuttle frame is put in its place for subsequent operation.
In order to lock the now folded filter media and strips in position and give strength and rigidity to the element a curable material is applied to the crests of strips 5, as shown in Fig. 3 and the apparatus shown at Fig. 2 using a feed device 17.
In a particular embodiment of the invention the curable material used is sodium silicate which can behave as a normal adhesive, but any other heat reactive setting material is to be included.
However, when the filter media and strips used are made from glass microfibre paper or any glass fibre paper the sodium silicate combines chemically with the glass fibres providing a fold locking principle of considerable strength when set hard and of a temperature resistance similar to that of the glass fibre. To facilitate the rapid setting of the sodium silicate or other curable material the suttle frame 13, containing the filter element assembly 12 consisting of folded and spaced filter media, strips and curable material, is passed through an area using a conveyor 16 which the temperature of the filter element assembly can be raised. In this particular embodiment sources of infra-red radiation 18 are used to raise the temperature.
When the shuttle frame 13 and with its partly finished folded filter element reaches the platen 19 it is manually removed, inverted and again fed through the soldium silicate applicator and heating area 1 8 thus locking the other side of the folded element. Alternatively the machine may consist of curable material applicators 17 and heating areas 18 on both sides of the shuttle frame thus enabling a simpler operation.
In the case of a finished filter element that is to be assembled into a cylindrical or "cartridge" form the folds or pleats running parallel to the longitudinal axis and evenly spaced radially around an inner cavity, only one side need be so locked using the apparatus of Fig. 2.
Claims (13)
1. A method of making a pleated filter having pleats open to a predetermined extent by folding filter material to form the pleats in which method a strip of additional material is folded with the filter material, so that the bulk and the resilience of the strip of additional material acts to open partially the pleats into which it has been folded to the predetermined extent and subsequently holding the pleats in place in that spacing.
2. A method according to claim 1, in which a strip of additional material is provided on each side of the filter material, and substantially every pleat has a said strip of additional material folded into it.
3. A method according to claim 1 or claim 2 in which the partially opened pleats are held in place by the application and curing or a curable material.
4. A method according to claim 3 in which the curable material is applied on both sides of the pleated filter material.
5. A method according to claim 4 in which the curable material is applied on both sides of the pleated filter material simultaneously.
6. A method according to any one of claims 3 to 5 in which the folding of the filter material and the partial opening of the pleats take place in a continuous process, and the pleated filter material so formed is cut into lengths and transported to a separate station at which the said curable material is applied and cured.
7. A method according to any one of claims 3 to 6 in which the curable material is sodium silicate.
8. A method of making a pleated filter substantially as herein described with reference to and as illustrated in the accompanying drawings.
9. Apparatus for performing the method of any one of the preceding claims through which the filter material passes and which has folding means which folds the filter material and the additional strip into tight concertina folds, and means downstream of the folding means for allowing the tight concertina folds to open to a predetermined extent against restraining means.
10. Apparatus according to claim 9 in which a ramp is provided downstream of the folding means over which the folded filter material passes in use and which in use promotes the opening of the said folds.
11. Apparatus according to claim 9 or claim 10 which has conveying means for receiving the filter material after it leaves the folding means and conveying it to means for applying curable material to the pleated filter material in order to hold the pleats in place, and means for severing the filter material after a predetermined number of folds have been received by the conveying means.
12. Apparatus for performing the method of any one of claims 1 to 8 substantially as herein described with reference to and as illustrated in the accompanying drawings.
13. A filter made by the method of any one of claims 1 to 8 using apparatus according to any one of claims 9 to 12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8100786A GB2071721B (en) | 1980-01-16 | 1981-01-12 | Filter pleat spacing process |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8001416 | 1980-01-16 | ||
| GB8100786A GB2071721B (en) | 1980-01-16 | 1981-01-12 | Filter pleat spacing process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2071721A true GB2071721A (en) | 1981-09-23 |
| GB2071721B GB2071721B (en) | 1983-11-23 |
Family
ID=26274157
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8100786A Expired GB2071721B (en) | 1980-01-16 | 1981-01-12 | Filter pleat spacing process |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2071721B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0173696A1 (en) * | 1984-02-13 | 1986-03-12 | American Filtrona Corporation | Pleated filter and method and apparatus for fabricating same |
| WO1988003833A1 (en) * | 1986-11-17 | 1988-06-02 | Flodins Filter Ab | Process for the production of filters, and a filter produced by the process |
| GB2228213A (en) * | 1989-02-15 | 1990-08-22 | Pall Corp | Air filter |
| US5098767A (en) * | 1989-02-15 | 1992-03-24 | Pall Corporation | Filter device with micropleats and macropleats |
| GB2260916A (en) * | 1989-02-15 | 1993-05-05 | Pall Corp | Air filter |
| EP0995474A2 (en) * | 1998-10-21 | 2000-04-26 | Aaf International | Apparatus and method for forming fibrous filter media and filter units |
| DE10157064A1 (en) * | 2001-11-21 | 2003-07-10 | Hans-Joachim Tittel | Pleating chip strips and other strips having similar shape, geometry and materials comprises using pleating machine to form gaps between both sides of pleated double folds |
-
1981
- 1981-01-12 GB GB8100786A patent/GB2071721B/en not_active Expired
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0173696A1 (en) * | 1984-02-13 | 1986-03-12 | American Filtrona Corporation | Pleated filter and method and apparatus for fabricating same |
| EP0173696A4 (en) * | 1984-02-13 | 1988-04-27 | American Filtrona Corp | Pleated filter and method and apparatus for fabricating same. |
| WO1988003833A1 (en) * | 1986-11-17 | 1988-06-02 | Flodins Filter Ab | Process for the production of filters, and a filter produced by the process |
| GB2228213A (en) * | 1989-02-15 | 1990-08-22 | Pall Corp | Air filter |
| US5098767A (en) * | 1989-02-15 | 1992-03-24 | Pall Corporation | Filter device with micropleats and macropleats |
| GB2260916A (en) * | 1989-02-15 | 1993-05-05 | Pall Corp | Air filter |
| GB2260916B (en) * | 1989-02-15 | 1993-10-27 | Pall Corp | Filter device |
| GB2228213B (en) * | 1989-02-15 | 1993-10-27 | Pall Corp | Filter device |
| EP0995474A2 (en) * | 1998-10-21 | 2000-04-26 | Aaf International | Apparatus and method for forming fibrous filter media and filter units |
| EP0995474A3 (en) * | 1998-10-21 | 2000-05-31 | Aaf International | Apparatus and method for forming fibrous filter media and filter units |
| DE10157064A1 (en) * | 2001-11-21 | 2003-07-10 | Hans-Joachim Tittel | Pleating chip strips and other strips having similar shape, geometry and materials comprises using pleating machine to form gaps between both sides of pleated double folds |
| DE10157064B4 (en) * | 2001-11-21 | 2004-12-23 | Hans-Joachim Tittel | Pleated filter material and method for producing such |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2071721B (en) | 1983-11-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| PE20 | Patent expired after termination of 20 years |
Effective date: 20010111 |