Air filter medium, air filter pack, and air filter unit

Patent metadata

Field	Value
Publication number	US-11406927-B2
Application number	US-201716338252-A
Country	US
Kind code	B2
Filing date	Sep 25, 2017
Priority date	Sep 30, 2016
Publication date	Aug 9, 2022
Grant date	Aug 9, 2022

Abstract

An air filter medium includes a first porous PTFE membrane and a second porous PTFE membrane. The air filter medium has a first main surface and a second main surface, and the first porous PTFE membrane and the second porous PTFE membrane are arranged so that an air flow moving from the first main surface to the second main surface passes through the first porous PTFE membrane and subsequently through the second porous PTFE membrane. A contact angle of the first porous PTFE membrane with water is in the range of 154° to 165°.

First claim

The invention claimed is:

1. An air filter medium has a first main surface and a second main surface, the air filter medium comprising:
a first porous PTFE membrane;
a second porous PTFE membrane; and
the first porous PTFE membrane and the second porous PTFE membrane are arranged so that an air flow moving from the first main surface to the second main surface passes through the first porous PTFE membrane and subsequently through the second porous PTFE membrane,
a contact angle of the first porous PTFE membrane with water is in the range of 155° to 157°, and
a contact angle of the second porous PTFE membrane with water is in the range of 148° to 153°.

2. The air filter medium according to claim 1 , wherein when poly-α-olefin in the form of polydisperse particles with an average particle diameter of 0.15 μm is passed through the air filter medium at a concentration of 20 to 40 g/m 3 and a linear flow velocity of 5.3 cm/sec to measure change in pressure drop, an amount of poly-a-olefin collected by the air filter medium is 20 mg/m 2 /Pa or more at a time point where the pressure drop reaches 500 Pa.

3. The air filter medium according to claim 1 , wherein when NaCl in the form of polydisperse particles with an average particle diameter of 0.5 μm is passed through the air filter medium at a concentration of 1 to 3 g/m 3 and a linear flow velocity of 5.3 cm/sec to measure change in pressure drop, an amount of NaCl collected by the air filter medium is 8 mg/m 2 /Pa or more at a time point where the pressure drop reaches 500 Pa.

4. The air filter medium according to claim 1 , wherein the pressure drop across the first porous PTFE membrane is 10 to 45 Pa.

5. An air filter pack comprising the air filter medium according to claim 1 , the air filter medium being pleated.

6. An air filter unit comprising the air filter pack according to claim 5 and a frame supporting the air filter pack.

Assignees

• Nitto Denko Corp

Inventors

• Niki Takashi
• Mori Masaaki
• Wada Shiho
• Daimon Atsushi
• Yanagi Toshiki

Classifications

• B01D39/1692 Primary

  Other shaped material, e.g. perforated or porous sheets · CPC title

• B32B3/28

  characterised by a layer comprising a deformed thin sheet {, i.e. the layer having its entire thickness deformed out of the plane}, e.g. corrugated, crumpled (B32B29/08 takes precedence) · CPC title

• B32B27/30

  comprising vinyl {(co)polymers; comprising acrylic (co)polymers} · CPC title

• B01D63/14

  Pleat-type membrane modules · CPC title

• B01D2239/1216

  Pore size · CPC title