# US 4,396,407 A · Multi-stage air filter

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- Number: US 4,396,407 A
- Document ID: US4396407A
- Status: Granted
- Kind: A
- Application number: 06/357,302
- Filed: 1982-03-11
- Granted: 1983-08-02
- Earliest claimed: 1982-03-11
- Assignees: Tecumseh Products Company
- Inventors: Paul T. Reese
- Web page: https://patentgrep.com/patent/US4396407A

## CPC

- B01D 46/10: Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces
- F02B 63/02: for hand-held tools
- F02M 35/024: using filters, e.g. moistened (F02M35/026 takes precedence; cleaning of the filtering material F02M35/08)
- Y10S 55/42: Foam filter materials
- 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)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

The invention provides an air cleaner assembly in combination with an engine having a blower housing with airflow circulating therethrough and a carburetor having an intake. The assembly comprises a duct having an inlet and an outlet with the inlet angularly disposed through the blower housing, an air cleaner housing having side walls and a bottom wall, and an outlet chamber having an inlet and an outlet in communication with the carburetor inlet. Within the air cleaner housing, a first interior wall is upstanding from the bottom wall and defines with certain side walls an intake chamber having an inlet communicating with the duct outlet, and a second interior wall upstanding from the bottom wall so that a filter chamber is formed between the interior walls having an outlet in its bottom wall so that the filter chamber and outlet chamber communicate through the filter chamber outlet and the outlet chamber inlet. The second interior wall and other side walls of the housing define a passageway in communication with the outlet chamber and the engine crankcase. Removably placed within the filter chamber is a filtering element, and removably attached to the air cleaner housing is a cover having side walls and a top wall such that the top wall is spaced above the filtering element to form therebetween a passageway, which provides communication between the intake chamber, filter chamber and passageway.

## Claims

### Claim 1

In combination with an engine including a blower housing having airflow circulating therethrough, and a carburetor having an intake, an air cleaner assembly comprising:
a duct having an inlet and an outlet, said duct inlet being angularly disposed through said blower housing,
an air cleaner housing having side walls; a bottom wall; a first interior wall upstanding from said bottom wall and defining with certain ones of said side walls an intake chamber within said housing, said intake chamber having an inlet and communicating with said duct through said duct outlet and said intake chamber inlet; a second interior wall upstanding from said bottom wall, said first and second interior walls and certains other ones of said side walls defining a filter chamber, said filter chamber having an outlet in its bottom wall, and said second interior wall and remaining ones of said side walls defining a passageway, said passageway having an opening connected to an engine crankcase;
an outlet chamber having an inlet and an outlet, said outlet chamber being in communication with said filter chamber through said filter chamber outlet and said outlet chamber inlet, and said inlet chamber outlet being in communication with said carburetor inlet;
means removably fitted within said filter chamber for filtering airflow passing through said filter chamber and into said outlet chamber; and
a cover having side walls and a top wall, and being removably attached to said air cleaner housing, said top wall being spaced above said filtering means and said first and second interior walls so as to define with said filtering means a passageway providing communication between said intake chamber, said filter chamber, and said passageway, whereby the airflow passing through said duct outlet is directed to said intake chamber, then directed horizontally by said passageway, and thereafter being redirected downwardly by said filter chamber.

### Claim 2 (depends on 1)

The assembly of claim 1 wherein said cover includes a baffle member extending downwardly from said top wall and preventing said filtering means from moving into and blocking said passageway.

### Claim 3 (depends on 2)

The assembly of claim 2 further including:
a baffle member upstanding from said filter chamber bottom wall to support said filtering means thereon and to provide a passageway defined between said filter means and said filter chamber bottom wall for permitting filtered air access to said outlet chamber.

### Claim 4 (depends on 3)

The assembly of claim 3 wherein said duct inlet is angularly disposed through said blower housing approximately 135.degree..

### Claim 5 (depends on 4)

The assembly of claim 4 wherein said filtering means is a polyurethane foam filter.

### Claim 6 (depends on 5)

The assembly of claim 5 wherein said foam filter has a porousness of approximately sixty pores per square inch.

### Claim 7 (depends on 6)

The assembly of claim 6 further including a felt filter removably fitted between said foam filter and said filter chamber bottom wall.

### Claim 8 (depends on 6)

The assembly of claim 6 further including a paper filter removably fitted between said foam filter and said filter chamber bottom wall.