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US 2010/0307338 A1Published application
Filter medium
AssigneeJohns Manville
InventorsChristian Hassman, Jörg Lehnert, Hans-Juergen Meitinger
Life of this patent
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Abstract
The present invention relates to a method for the manufacture of a multilayered filter medium whose air permeability is at least 500 l/m2sec and a multilayered filter medium obtainable by said method which, when charged with 5 mg/cm2 SAE-dust of the class “fine”, exhibits a pressure increase of no more than 100 Pa.
Claims26
A method for the manufacture of a multilayered filter medium whose air permeability is at least 500 l/m2sec comprising the measures:
- a) Formation of a textile fabric comprising carrier and melt binder fibres wherein the carrier fibres consist of a polyester and the melt binder fibres consist of a polymer whose melting point is at least 5° C. below the melting point of the carrier fibres and the carrier and melt binder fibres have a titre in the region of 1 to 2 dtex,
- b) Formation of a further textile fabric on the textile surface formed in step a) comprising carrier and melt binder fibres wherein the carrier fibres consist of a polyester and the melt binder fibres consist of a polymer whose melting point is at least 5° C. below the melting point of the carrier fibres and the carrier and melt binder fibres have a titre in the region of 2 to 4 dtex,
- c) Formation of a further textile fabric on the textile surface formed in step b) comprising carrier and melt binder fibres wherein the carrier fibres consist of a polyester and the melt binder fibres consist of a polymer whose melting point is at least 5° C. below the melting point of the carrier fibres and the carrier and melt binder fibres have a titre in the region of 4 to 12 dtex,
- d) The portion of the textile fabric formed in step a) is 20 to 60% by weight, the portion of the textile fabric formed in step b) is 10 to 40% by weight and the portion of the textile fabric formed in step c) is 10 to 40% by weight,
- e) The portion of the melt binder fibres in textile fabric formed in accordance with steps a) to c) is 5 to 40% by weight,
- f) The weight per unit area of the textile fabric formed in accordance with steps a) to c) is 50 to 400 g/m2,
- g) Pre-solidification of the multilayered textile fabric formed in accordance with steps a) to c) by means of a heated roller whose surface temperature is at least 70° C.,
- h) Calendering of the pre-solidified multilayered textile fabric formed in accordance with step g) by means of a calender whose surface temperature is at least 10° C. below the melting temperature of the melt binder fibres and a contact pressure/line pressure of at least 20 daN.
- i) Introduction of the multilayered textile fabric calendered in accordance with step h) into a hot-air oven whose minimum temperature is equal to or above the melting temperature of the melt binder fibres and whose maximum temperature is at least 10° C. below the melting temperature of the carrier fibres wherein the introduced textile fabric expands and the thickness of the textile fabric increases by at least 30% with respect to the introduced textile fabric,
- j) Cooling of the melt binder-solidified multilayered filter medium and assembly.
7 more elements
A multilayered filter medium whose air permeability is at least 500 l/m2sec and which has a least three concrete layers, wherein
- I) the first layer is a melt binder-solidified textile fabric whose fibres have a titre in the range of 1 to 2 dtex,
- II) the second layer is a melt binder-solidified textile fabric whose fibres have a titre in the range of 2 to 4 dtex,
- III) the third layer is a melt binder-solidified textile fabric whose fibres have a titre in the range of 4 to 12 dtex,
- IV) the portion of the first layer of the multilayered filter medium is 20 to 60% by weight, the portion of the second layer of the multilayered filter medium is 10 to 40% by weight and the portion of the third layer of the multilayered filter medium is 10 to 40% by weight,
- V) the melt binder portion in the layers in accordance with I) to III) amounts to 5 to 40% by weight in total,
- VI) the weight per unit area of the layers in accordance with I) to III) amounts to 50 to 400 g/m2 in total and
- VII) the filter medium, when charged with 5 mg/cm3 SAE dust of the class “fine”, exhibits a pressure increase of no more than 100 Pa.
4 more elements
Dependencies are inferred from the claim text.