# US 2013/0220918 A1 · Double-layer filter strcutre

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- Number: US 2013/0220918 A1
- Document ID: US20130220918A1
- Status: Published application
- Kind: A1
- Application number: 13/404,080
- Filed: 2012-02-24
- Published: 2013-08-29
- Earliest claimed: 2012-02-24
- Assignees: Insonic Company
- Inventors: Hideo ISHIKURA
- Web page: https://patentgrep.com/patent/US20130220918A1

## CPC

- B01D 29/111: {Making filtering elements}
- B01D 29/21: with corrugated, folded or wound sheets
- B01D 29/58: arranged concentrically or coaxially
- B01D 2201/127: with means for keeping the spacing between the pleats
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

The instant disclosure relates to a double-layer filter structure disposed in an oil filter. The double-layer filter structure includes two individual filter media for removing impurities of different sizes in the engine oil. The double-layer filter structure includes a first filter medium and a second filter medium. The first filter medium has a plurality of wave-shaped and annularly arranged first folding portions. Similarly, the second filter medium has a plurality of wave-shaped and annularly arranged second folding portions. Each of the first folding portions has a mating portion retained by the second folding portions correspondingly.

## Claims

### Claim 1

A double-layer filter structure, comprising:
a first filter medium having a plurality of wave-shaped and annularly arranged first folding portions; and
a second filter medium having a plurality of wave-shaped and annularly arranged second folding portions, wherein the first filter medium is surrounded by the second filter medium, while each of the first folding portions has a mating portion retained by the second folding portions correspondingly.

### Claim 2 (depends on 1)

The double-layer filter structure as claimed in claim 1, wherein the length of the first folding portion is larger than the length of the second folding portion along the radial direction.

### Claim 3 (depends on 1)

The double-layer filter structure as claimed in claim 1, wherein the pore size of the second filter medium is smaller than the pore size of the first filter medium.

### Claim 4 (depends on 1)

The double-layer filter structure as claimed in claim 1, wherein the first filter medium and the second filter medium have identical height.

### Claim 5 (depends on 4)

The double-layer filter structure as claimed in claim 4, further comprising a pair of fixing rings disposed at opposite ends of the first filter medium and the second filter medium, and wherein the first folding portions and the second folding portions are fixed to the fixing rings.

### Claim 6 (depends on 5)

The double-layer filter structure as claimed in claim 5, wherein each of the fixing rings has a central hole formed thereon, and wherein the diameter of the central hole is substantially equal to the inner diameter of the first filter medium.