# US 7,744,758 B2 · Liquid filter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,758 B2 - Document ID: US7744758B2 - Status: Granted - Kind: B2 - Application number: 11/354,161 - Filed: 2006-02-15 - Published: 2006-08-31 - Granted: 2010-06-29 - Earliest claimed: 2005-02-15 - Assignees: Mann+Hummel GmbH - Inventors: Klemens Dworatzek; Ralf Bauder; Karlheinz Muenkel; Duc Cuong Nguyen - Web page: https://patentgrep.com/patent/US7744758B2 ## CPC - B01D 27/144: {arranged concentrically or coaxially} - B01D 35/153: Anti-leakage or anti-return valves - B01D 35/30: Filter housing constructions - B01D 2201/0415: Details of supporting structures - B01D 2201/4015: Bayonet connecting means - B01D 2201/4046: Means for avoiding false mounting of different parts - 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 A liquid filter, especially oil filter for an internal combustion engine, having a cup-shaped housing with a liquid inlet and a liquid outlet, a filter element arranged with a seal between the inlet and outlet, and a one-piece barrier membrane arranged in the area of the opening of the cup-shaped housing such that the liquid inlet and/or the liquid outlet can be closed by the barrier membrane. ## Claims ### Claim 1 A liquid filter comprising a cup-shaped housing with a liquid inlet and a liquid outlet in communication with a discharge chamber of said filter; a filter element sealingly disposed in said housing between the inlet and the outlet, and a one-piece barrier membrane disposed adjacent the opening of the cup-shaped housing so that the liquid inlet and the liquid outlet can be closed by the barrier membrane, wherein the barrier membrane includes a circular connecting plate having a first return flow barrier arranged on the radially outer edge thereof and a concentric second return flow barrier arranged radially inwardly thereof, the connecting plate is provided with connecting elements for detachably connecting the barrier membrane to an end disk of the filter element or to a cover plate, and the concentric second return flow barrier includes an outlet seal valve having a duckbill configuration, said duckbill constructed as a flexible tube continuation extending from said connecting plate into said discharge chamber, said flexible tube forming a pair of tilted, opposing, generally flat members converging to form a self-closing slit, said slit configured to sealably close said liquid outlet, wherein curved sidewalls of said flexible tube are operable to tension said flat members to maintain closure of said slit, wherein the duckbill is directed towards the interior of the filter element, wherein the duckbill is configured to be mechanically opened during installation. ### Claim 2 (depends on 1) A liquid filter according to claim 1, wherein the filter element has a hollow cylindrical shape and an end disk adjacent the opening of the cup-shaped housing, and the barrier membrane is affixed to the end disk of the filter element. ### Claim 3 (depends on 2) A liquid filter according to claim 2, wherein the barrier membrane is non-detachably affixed to the end disk. ### Claim 4 (depends on 1) A liquid filter according to claim 1, wherein the barrier membrane is affixed to a cover plate of the filter housing. ### Claim 5 (depends on 4) A liquid filter according to claim 4, wherein the barrier membrane is non-detachably affixed to the cover plate. ### Claim 6 (depends on 1) A liquid filter according to claim 1, wherein the barrier membrane is affixed to a central support tube of the filter element. ### Claim 7 (depends on 6) A liquid filter according to claim 6, wherein the barrier membrane is non-detachably affixed to the support tube. ### Claim 8 (depends on 1) A liquid filter according to claim 1, wherein the barrier membrane is formed of a thermoplastic, elastomeric material. ### Claim 9 (depends on 1) A liquid filter according to claim 1, wherein the barrier membrane is made of a two-component synthetic resin material. ### Claim 10 (depends on 1) A liquid filter according to claim 1, wherein the first return flow barrier in the closed state lies in sealing contact against a concentric sealing contour arranged radially outwardly thereof. ### Claim 11 (depends on 1) A liquid filter according to claim 1, wherein said filter is a lubricating oil filter for an internal combustion engine. ### Claim 12 (depends on 1) The liquid filter of claim 1, wherein said outlet seal valve is configured to be held opened by insertion of an outlet pipe into said duckbill, thereby permitting flow through said outlet. ### Claim 13 (depends on 1) The liquid filter of claim 1, wherein said seal valve is configured and arranged such that outflow through said outlet acts to aid closure of said seal valve.