High temperature filter assembly

Patent metadata

Field	Value
Publication number	US-2018193784-A1
Application number	US-201515740333-A
Country	US
Kind code	A1
Filing date	Jul 10, 2015
Priority date	Jul 10, 2015
Publication date	Jul 12, 2018
Grant date	—

Abstract

A high efficiency air filter assembly ( 100 ) for high temperature applications comprising: a filter core ( 102 ) including a unitary sheet of air-permeable filter media folded in accordion fashion to form a plurality of side-by-side pleats with zig-zag edges on two opposite sides and flat panels on the other two sides, and a spacer member between opposing walls of successive pleats, a box-like metal frame ( 108 ) enclosing said filter core on four sides in air tight engagement to define an air flow opening extending between upstream and downstream sides of said assembly, wherein the zig-zag edges of the unitary sheet of air-permeable filter media are sealingly embedded in a solid inorganic sealant composition ( 118 ) in the frame, and wherein the unitary sheet of air-permeable filter media preferably consists of a binder-free glass or mineral fiber filter media. Use of the high efficiency air filter assembly in high temperature applications wherein the filter assembly is repeatedly or continuously heated to a temperature in the range of 200-500° C.

First claim

1 . High efficiency air filter assembly for high temperature applications comprising:
a filter core including a unitary sheet of air-permeable media folded in accordion fashion to form a plurality of side-by-side pleats with zig-zag edges on two opposite sides and flat panels on the other two sides, and a spacer member between opposing walls of successive pleats, a box-like metal frame enclosing said filter core on four sides in air tight engagement to define an air flow opening extending between upstream and downstream sides of said assembly, wherein the zig-zag edges of the unitary sheet of air-permeable filter media are sealingly embedded in a solid inorganic sealant composition in the frame.

2 . High efficiency air filter assembly according to claim 1 , wherein the unitary sheet of air-permeable filter media consists of a binder-free glass or mineral fiber filter media.

3 . High efficiency air filter assembly according to claim 2 , wherein the binder-free glass or mineral fiber filter media is a glass fiber filter media made of binder-free borosilicate glass fiber.

4 . High efficiency air filter assembly according to claim 1 , wherein the spacer members are made of stainless steel.

5 . High efficiency air filter assembly according to claim 1 , wherein the inorganic sealant composition is a geopolymer composition which can be provided in a liquid state, hardenable to a solid state.

6 . High efficiency air filter assembly according to claim 1 , wherein the filter core and solid inorganic sealant composition are resiliently suspended within the frame.

7 . High efficiency air filter assembly according to claim 1 , wherein the filter core and solid inorganic sealant composition can move resiliently in relation to the frame.

8 . High efficiency air filter assembly according to claim 7 , wherein the resilient suspension between said filter core and solid inorganic sealant composition is provided by a compressible heat resistant fibrous material arranged between the solid inorganic sealant composition and the frame and between the flat panel sides of the filter core and the frame.

9 . High efficiency air filter assembly according to claim 8 , wherein the heat resistant fibrous material substantially consists of glass or aluminum oxide fibers or a combination thereof, preferably the heat resistant fibrous material substantially consists of aluminum oxide fibers.

10 . High efficiency air filter assembly according to claim 8 , wherein the heat resistant fibrous material arranged between the solid inorganic sealant composition and the frame is sealed between the solid inorganic sealant composition and the frame, such that the heat resistant fibrous material is not directly exposed to the downstream side of the filter assembly.

11 . High efficiency air filter assembly according to claim 8 , wherein the heat resistant fibrous material arranged between the flat panel sides of the filter core and the frame are enveloped by the unitary sheet of air-permeable filter media, such that the heat resistant fibrous material is not directly exposed to the downstream side of the filter assembly.

12 . High efficiency air filter assembly according to claim 1 , wherein the inorganic sealant composition is separated from the frame by a flexible liner.

13 . High efficiency air filter assembly according to claim 1 , wherein the filter assembly comprises a flexible liner arranged at an inner surface of the frame, said flexible liner preventing direct contact between the inorganic sealant composition and the frame and providing a resilient contact between the inorganic sealant composition and the frame such that the support frame can expand on heating without subjecting the inorganic sealant to mechanical stress.

14 . High efficiency air filter assembly according to claim 12 , wherein the flexible liner is comprised of a sheet of HEPA filter media.

15 . High efficiency air filter assembly according to claim 1 , wherein the air filter assembly is HEPA class H13 or higher according to European Norm EN 1822:2009.

16 . High efficiency air filter assembly according to claim 15 , wherein the air filter assembly is capable of maintaining a HEPA class of H13 or higher according to European Norm EN 1822:2009, over an extended period of use at temperatures in the range 200-500° C.

17 . High efficiency air filter assembly according to claim 1 , wherein the box-like metal frame comprises:
a pair of substantially identical, rectangular side casings having a recess configured to receive a flat panel side of the filter core and having a lip of lesser width than said side casings extending outwardly from each end thereof, and a pair of substantially identical, rectangular end casings having a width equal to the width of said side casings and having a recess configured to receive a zig-zag side of the filter core.

18 . High efficiency air filter assembly according to claim 1 , wherein the recesses of the box-like metal frame have substantially smooth inner surfaces.

19 . High efficiency air filter assembly according to claim 1 , wherein the length of the lips of the side casings substantially corresponds to the depth of the recesses of the end casings.

20 . High efficiency air filter assembly according to claim 1 , wherein the box-like metal frame is formed of stainless steel.

21 . High efficiency air filter assembly according to claim 1 , wherein the box-like metal frame comprises a reinforcement structure, said reinforcement structure comprising a first unitary rectangular plate arranged around the periphery of the upstream side of the filter assembly and fixed to all four sides of the metal frame such that torsional deformation of the metal frame is prevented.

22 . High efficiency air filter assembly according to claim 1 , wherein the box-like metal frame comprises a reinforcement structure, said reinforcement structure comprising a second unitary rectangular plate arranged around the periphery of the downstream side of the filter assembly and fixed to all four sides of the metal frame such that torsional deformation of the metal frame is prevented.

23 . High efficiency air filter assembly according to claim 22 , wherein the box-like metal frame comprises a reinforcement structure, said reinforcement structure comprising a first unitary rectangular plate arranged around the periphery of the upstream side of the filter assembly and fixed to all four sides of the metal frame such that torsional deformation of the metal frame is prevented, and wherein the box-like metal frame comprises a reinforcement structure, said reinforcement structure further comprising at least two reinforcement bars arranged at different sides of the metal frame, each reinforcement bar extending between, and being rigidly fixed to, the first and second rectangular plates.

24 . High efficiency air filter assembly according to claim 23 , wherein the reinforcement bars are arranged in the area of the support frame where load is to be applied when the filter is clamped in a filter housing.

25 . High efficiency air filter assembly according to claim 21 , wherein the inner edges of the first and/or second unitary rectangular plate at least cover any compressible heat resistant fibrous material and solid inorganic sealant composition arranged between the filter core and the frame.

26 . High efficiency air filter assembly according to claim 25 , wherein

Assignees

• Camfil Ab

Inventors

• Englund Fredrik
• Hugert Sverker

Classifications

• B01D39/2017

  the material being filamentary or fibrous · CPC title

• B01D2273/20

  High temperature filtration · CPC title

• B01D2201/0415

  Details of supporting structures · CPC title

• B01D46/0005 Primary

  Mounting of filtering elements within casings, housings or frames (B01D46/2422 takes precedence) · CPC title

• B01D46/523

  with means for maintaining spacing between the pleats or folds · CPC title