Liquid filter with separate and calibrated vapor release

• US 6,758,980 B2
• Filed: 11/03/2003
• Issued: 07/06/2004
• Est. Priority Date: 08/22/2001
• Status: Expired due to Term

• Current Assignee: Cummins Filtration Incorporated (Cummins Incorporated)
• Original Assignee: Fleetguard, Inc. (Cummins Incorporated)
• Inventors: Jiang, Zemin, Scheuren, John, Clevenger, John W. Jr., Prater, Ted Franklin, Verdegan, Barry M.
• Primary Examiner(s): Cecil, Terry K.
• Application Number:
  US10/700,211
• Publication Number:
  US 20040094459A1
• Time in Patent Office: 246 Days
• Field of Search: 210/94, 210/95, 210/130, 210/132, 210/85, 210/86, 210/133, 210/437, 210/440, 210/456, 210/90, 210/120, 210/429, 210/430, 210/431, 210/443, 210/484, 210/488, 116/276, 116/268
• US Class Current: 210/767
• CPC Class Codes: B01D 35/143 Filter condition indicators
• CPC Class Codes: B01D 36/001 Filters in combination with devices for the removal of gas, air purge systems
• CPC Class Codes: B01D 36/003 Filters in combination with devices for the removal of liquids B01D35/185 takes precedence

Abstract

A liquid filter (10) housing an annular filter element (16) has an annular space or inlet chamber (24) between the filter element and the housing and viewable through the housing such that an operator can see the level of liquid in the inlet chamber as an indication of when to replace the filter element, the higher the level of liquid in the inlet chamber the greater the pressure drop across the filter element. A change interval plugging indicator (102), preferably part of the filter element, is provided by a gas trap and pressure responsive release mechanism (104) trapping gas in the upper section (23) of the inlet chamber until a designated release pressure is reached, corresponding to a desired terminal pressure, to prevent premature plugging indication otherwise indicated by rising liquid level in the inlet chamber. Accurate and reliable calibration is enabled by separating the filtration function and the plugging indication function.

Claims

1. A liquid filter comprising a housing having an inlet and an outlet, a filter element in said housing and having an upstream outer face communicating with said inlet, and a downstream inner face communicating with said outlet, said filter element filtering liquid passing therethrough from said outer face to said inner face, said housing having a sidewall which defines with said outer face an inlet chamber therebetween having an upper section and a lower section, such that as liquid enters said inlet chamber from said inlet, gas in said liquid rises to said upper section of said inlet chamber, a low level of liquid indicating a low pressure drop non-plugged condition of said filter element, the higher the level of said liquid in said inlet chamber the greater the pressure drop across said filter element and the greater the plugging of said filter element, a change interval plugging indicator in said housing comprising a gas trap and pressure responsive release mechanism trapping said gas in said upper section of said inlet chamber until a designated release pressure is reached, corresponding to a desired terminal pressure, to prevent premature plugging indication otherwise indicated by rising liquid level in said inlet chamber, said change interval plugging indicator comprising an outer wrap around said outer face of said filter element in said upper section of said inlet chamber and blocking gas flow therethrough at least at pressures below said designated release pressure, said outer wrap having a lower end which defines a lower end of said upper section of said inlet chamber and an upper end of said lower section of said inlet chamber, wherein said gas is trapped in said upper section of said inlet chamber when liquid in said inlet chamber rises above said lower end of said outer wrap, said filter element being an axially extending annulus having an outer surface providing said outer face, and having an inner surface providing said inner face and defining a hollow interior, said filter element having a lower axial end having an opening at said hollow interior and communicating with said outlet, said filter element having an upper axial end closed by an end cap spanning said hollow interior, said end cap having a section of porous media over said hollow interior, said porous media having a lower first side communicating with said hollow interior, and having an upper second side communicating with said upper section of said inlet chamber, said porous media blocking gas flow therethrough below said designated release pressure, and passing gas flow therethrough above said designated release pressure wherein said designated release pressure corresponding to said desired terminal pressure is calibrated according to bubble point of said porous media.

2. The liquid filter according to claim 1 wherein said housing has an upper end cap having a plurality of spokes forming one or more radially extending gas passages therebetween, said spokes engaging said end cap of said filter element and applying axial pressure thereagainst holding said filter element in place, said upper second side of said porous media communicating through said one or more radially extending gas passages with said upper section of said inlet chamber.

3. In a liquid filter comprising a housing having an inlet and an outlet, a filter element in said housing and having an upstream outer face communicating with said inlet, and a downstream inner face communicating with said outlet, said filter element filtering liquid passing therethrough from said outer face to said inner face, said housing having a sidewall which defines with said outer face an inlet chamber therebetween having an upper section and a lower section, such that as liquid enters said inlet chamber from said inlet, gas in said liquid rises to said upper section of said inlet chamber, a low level of liquid indicating a low pressure drop non-plugged condition of said filter element, the higher the level of said liquid in said inlet chamber the greater the pressure drop across said filter element and the greater the plugging of said filter element, such that during use, liquid level in said inlet chamber rises and gas disappears as permitted by gas flow through said filter element, the rising of said liquid level and the disappearing of said gas being used in the prior art for indicating a change interval for the filter element, whereby said filter media provides both a filtration function and a plugging indication function in the prior art,

an improved interval change plugging indication method comprising separating said filtration function and said plugging indication function by trapping gas in said inlet chamber and releasing said gas in response to a designated release pressure corresponding to a desired terminal pressure, and comprising performing said filtration function with a first member provided by said filter element, and performing said plugging indication function with second and third members different than said first member, and comprising providing said second member by an outer wrap around said filter element in said upper section of said inlet chamber and blocking gas flow therethrough at least at pressures below a designated release pressure, corresponding to a desired terminal pressure, said outer wrap having a lower end which defines a lower end of said upper section of said inlet chamber and an upper end of said lower section of said inlet chamber, wherein gas is trapped in said upper section of said inlet chamber when liquid in said inlet chamber rises above said lower end of said outer wrap, said filter element being an axially extending annulus having an outer surface and having an inner surface defining a hollow interior, said filter element having a lower axial end having an opening at said hollow interior and communicating with said outlet, said filter element having an upper axial end closed by an end cap spanning said hollow interior, and comprising providing said third member by a section of porous media in said end cap of said filter element over said hollow interior, said porous media having a lower first side communicating with said hollow interior, and having an upper second side communicating with said upper section of said inlet chamber, said porous media blocking gas flow below said designated release pressure, and passing gas flow therethrough above said designated release pressure, said method further comprising calibrating said designated release pressure corresponding to said desired terminal pressure according to bubble point of said porous media.