# US 10,765,977 B2 · Fuel filter insert, and fuel filter comprising a prefilter element and a main filter element and comprising a water separating unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,765,977 B2 - Document ID: US10765977B2 - Status: Granted - Kind: B2 - Application number: 15/702,998 - Filed: 2017-09-13 - Published: 2018-02-01 - Granted: 2020-09-08 - Earliest claimed: 2015-03-13 - Assignees: Mann+Hummel GmbH - Applicants: Mann+Hummel GMBH - Inventors: Christoph Baumann; Lars Spelter; Idriss Razgani; Jonas Eble; Christopher Mueller - Web page: https://patentgrep.com/patent/US10765977B2 ## CPC - B01D 35/26: Filters with built-in pumps {filters provided with a pump mounted in or on the casing (aquarium pumps or filters A01K63/04)} - B01D 29/21: with corrugated, folded or wound sheets - B01D 29/58: arranged concentrically or coaxially - B01D 36/003: {Filters in combination with devices for the removal of liquids (B01D35/185 takes precedence)} - F02M 37/24: characterised by water separating means - F02M 37/28: with means activated by the presence of water, e.g. alarms or means for automatic drainage - F02M 37/32: characterised by filters or filter arrangements - F02M 37/44: Filters structurally associated with pumps - B01D 2201/295: with projections extending in a radial outward direction, e.g. for use as a guide, spacing means - B01D 2201/298: End caps common to at least two filtering elements - B01D 2201/34: Seals or gaskets for filtering elements - B01D 2201/40: Special measures for connecting different parts of the filter - B01D 2201/46: Several filtrate discharge conduits each connected to one filter element or group of filter elements - F02M 37/54: characterised by air purging means (having priming pumps F02M37/16) - 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) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF ## Abstract A fuel filter insert for a fuel filter is provided with a prefilter element and a main filter element which are arranged one atop the other in an axial direction relative to a longitudinal axis of the fuel filter insert. The main filter element has a water separating unit configured to separate water contained in a fuel to be filtered. The water separating unit has a water discharge channel for water separated from the fuel, wherein the water discharge channel is extending in the axial direction at least partially through the prefilter element. A fuel filter with such a fuel filter insert has a filter housing accommodating the fuel filter insert and the water discharge channel of the fuel filter insert is fluidically connected with a water collecting chamber of the filter housing. ## Claims ### Claim 1 A fuel filter insert for a fuel filter, the fuel filter insert comprising: a prefilter element; and a main filter element arranged atop the prefilter element in an axial direction relative to a longitudinal axis of the fuel filter insert; the main filter element comprising a water separating unit configured to separate water contained in a fuel to be filtered; the water separating unit comprising a water discharge channel for water separated from the fuel, wherein the water discharge channel is extending in the axial direction at least partially through the prefilter element; wherein the fuel filter insert further comprises: a flow channel for fuel that has been prefiltered by the prefilter element, wherein the flow channel is arranged between the prefilter element and the main filter element, wherein the flow channel is immediately delimited in the axial direction by an end disc of the prefilter element that is facing the main filter element and by an end disc of the main filter element that is facing the prefilter element. ### Claim 2 (depends on 1) The fuel filter insert according to claim 1, further comprising a wall element disposed on the main filter element and extending in the axial direction away from the main filter element, wherein the water discharge channel is delimited outwardly in a radial direction relative to the longitudinal axis by the wall element. ### Claim 3 (depends on 2) The fuel filter insert according to claim 2, wherein the main filter element comprises a lower end disc and wherein the wall element is attached to the lower end disc. ### Claim 4 (depends on 3) The fuel filter insert according to claim 3, wherein the wall element is integrally formed on the lower end disc. ### Claim 5 (depends on 2) The fuel filter insert according to claim 2, wherein the prefilter element comprises a lower end disc that is facing away from the main filter element, a first sealing collar arranged on a radially inner side of the lower end disk of the prefilter element; a second sealing collar arranged on a radially outer side of the wall element; wherein a receiving slot is arranged between the first sealing collar and the second sealing collar; wherein the wall element and the lower end disc of the prefilter element together delimit the receiving slot which is configured to receive a water discharge socket of a filter housing with the first and second sealing collars sealing against the water discharge socket of the filter housing. ### Claim 6 (depends on 1) The fuel filter insert according to claim 1, wherein the water separating unit of the main filter element comprises a water separating gap comprising an end that is fluidically connected to the water discharge channel. ### Claim 7 (depends on 6) The fuel filter insert according to claim 6, wherein the main filter element comprises a screen tube and a filter medium, wherein the water separating gap is formed between the screen tube and the filter medium of the main filter element. ### Claim 8 (depends on 1) The fuel filter insert according to claim 1, wherein the water separating unit comprises a coalescing medium. ### Claim 9 (depends on 8) The fuel filter insert according to claim 8, wherein the coalescing medium is arranged fluidically downstream of a filter medium of the main filter element. ### Claim 10 (depends on 1) The fuel filter insert according to claim 1, wherein the end disc of the prefilter element that is facing the main filter element and the end disc of the main filter element that is facing the prefilter element are connected with each other to enable common removal of the prefilter element and the main filter element from a filter housing. ### Claim 11 (depends on 10) The fuel filter insert according to claim 10, wherein the end disc of the prefilter element that is facing the main filter element and the end disc of the main filter element that is facing the prefilter element are formed together as one piece. ### Claim 12 A fuel filter comprising: a filter housing; a fuel filter insert disposed in the filter housing and comprising a prefilter element and a main filter element arranged atop the prefilter element in an axial direction relative to a longitudinal axis of the fuel filter insert, wherein the main filter element comprises a water separating unit configured to separate water contained in a fuel to be filtered, and wherein the water separating unit comprises a water discharge channel for water separated from the fuel, wherein the water discharge channel is extending in the axial direction at least partially through the prefilter element; wherein the water discharge channel of the fuel filter insert is fluidically connected with a water collecting chamber of the filter housing; wherein the fuel filter insert further comprises: a flow channel for fuel that has been prefiltered by the prefilter element, wherein the flow channel is arranged between the prefilter element and the main filter element, wherein the flow channel is immediately delimited in the axial direction by an end disc of the prefilter element that is facing the main filter element and by an end disc of the main filter element that is facing the prefilter element. ### Claim 13 (depends on 12) The fuel filter according to claim 12, wherein the fuel filter insert further comprises a wall element disposed on the main filter element and extending in the axial direction away from the main filter element, wherein the water discharge channel is delimited outwardly in a radial direction relative to the longitudinal axis by the wall element, wherein the prefilter element comprises a lower end disc that is facing away from the main filter element, a first sealing collar arranged on a radially inner side of the lower end disk of the prefilter element; a second sealing collar arranged on a radially outer side of the wall element; wherein a receiving slot is arranged between the first sealing collar and the second sealing collar; wherein the wall element and the lower end disc of the prefilter element together delimit the receiving slot; wherein the filter housing comprises a water discharge socket fluidically connected with the water collecting chamber of the filter housing, wherein the water discharge socket is seal-tightly projecting into the receiving slot between the first and second sealing collars, the first and second sealing collars sealing against the water discharge socket. ### Claim 14 (depends on 13) The fuel filter according to claim 13, wherein the water discharge channel is delimited inwardly in the radial direction by a tubular element. ### Claim 15 (depends on 14) The fuel filter according to claim 14, wherein the tubular element is part of a screen tube of the water separating unit. ### Claim 16 (depends on 14) The fuel filter according to claim 14, wherein the tubular element is part of a venting tube arranged in an interior of the fuel filter insert. ### Claim 17 (depends on 16) The fuel filter according to claim 16, wherein the venting tube is fastened on the filter housing. ### Claim 18 (depends on 16) The fuel filter according to claim 16, wherein the venting tube is locked or screw-connected by the tube element to the filter housing. ### Claim 19 (depends on 16) The fuel filter according to claim 16, wherein the venting tube comprises an end that opens into a fuel return of the filter housing, wherein the fuel return is fluidically connectable with a fuel tank. ### Claim 20 A fuel filter comprising: a filter housing; a fuel filter insert disposed in the filter housing and comprising a prefilter element and a main filter element arranged atop the prefilter element in an axial direction relative to a longitudinal axis of the fuel filter insert, wherein the main filter element comprises a water separating unit configured to separate water contained in a fuel to be filtered, and wherein the water separating unit comprises a water discharge channel for water separated from the fuel, wherein the water discharge channel is extending in the axial direction at least partially through the prefilter element; wherein the water discharge channel of the fuel filter insert is fluidically connected with a water collecting chamber of the filter housing; wherein the fuel filter further comprises: a fuel pump, wherein the filter housing comprises a lateral fuel outlet connected to the prefilter element and a lateral fuel inlet connected to the main filter element, wherein the pump is connected between the lateral fuel outlet and the lateral fuel inlet, wherein the fuel filter insert further comprises a flow channel for fuel that has been prefiltered by the prefilter element, wherein the flow channel is arranged between the prefilter element and the main filter element, wherein the flow channel is immediately delimited in the axial direction by an end disc of the prefilter element that is facing the main filter element and by an end disc of the main filter element that is facing the prefilter element, wherein said end disc of the prefilter element and said end disc of the main filter element are seal-tightly contacting an inner side of the filter housing, and wherein the flow channel is fluidically connectable by the lateral fuel outlet with the fuel pump to pump the fuel prefiltered by the prefilter element through the fuel inlet to the main filter element.