Filter condition indicator

• US 4,153,003 A
• Filed: 11/29/1974
• Issued: 05/08/1979
• Est. Priority Date: 04/22/1974
• Status: Expired due to Term

• Current Assignee: Time Gard Products, Inc.
• Original Assignee: Adams John W & Dolores C, Bradbury Edward T & Charlotte L, Contreras Gilbert & Dolores D, Lefevre Robert A & Dorthy J, Seeley CARL L & Colene, Willis WM M & Isabel
• Inventors: Willis, William M.
• Primary Examiner(s): Yasich, Daniel M.
• Application Number:
  US05/528,338
• Time in Patent Office: 1,621 Days
• Field of Search: 116/DIG. 42, 116/DIG. 25, 116/117 R, 116/114 PV, 210/90, 73/38, 73/407, 73/419, 55/274
• US Class Current: 116/268
• CPC Class Codes: G01L 7/16 in the form of pistons
• CPC Class Codes: G01M 13/00 Testing of machine parts
• CPC Class Codes: Y10S 116/25 Air filter condition indicator
• CPC Class Codes: Y10S 55/34 Indicator and controllers

Abstract

A pressure differential indicator for indicating a change in a fluid pressure differential across a component in a fluid system, such as an oil filter, has piston means, means for communicating fluid pressures of said system upstream and downstream of said component to opposite sides of said piston means, respectively, and differential means associated with the piston means for normally balancing the resultant forces of said pressure on opposite sides of said piston means at a given predetermined pressure differential across said component whereby said piston means is responsive to an increase or decrease in the pressure differential above or below said predetermined differential pressure to indicate a clean or clogged filter condition. Means are provided for holding the piston means in its last position upon relief of said first and second pressures to indicate the operating filter condition when the system is not operating. In alternative embodiments, the indicator includes "kicker" means to start its motion, is responsive at all times to pressure differential above or below a predetermined value and includes a number of embodiments of adaptors to accommodate its introduction into fluid systems.

Claims

1. A pressure differential indicator comprising:

first and second piston means in first and second chambers, respectively,

means to subject said first and second piston means to first and second pressures respectively,

interconnecting means extending into each of said first and second chambers and connected between said first and second piston means, for requiring that the pressure force produced by said first pressure on said first piston means to enable said first piston means to move said first and second piston means together with said interconnecting means be a predetermined amount larger than the pressure force produced by said second pressure on said second piston means to enable said second piston means to move said first and second piston means together with said interconnecting means, and

kicker means provided in said first chamber for sealing off a portion of said first piston means from the pressure in said first chamber to reduce the area of said first piston means subjected to said first pressure when said first piston means is seated therein and only until said first piston means has begun to move said first and second piston means together with said interconnecting means and to thereafter no longer reduce said area, whereby said first piston means moves said first and second piston means together with said interconnecting means with a snap action.

2. The pressure differential indicator of claim 1 comprising;

second kicker means provided in said second chamber for sealing off a portion of said second means from the pressure in said second chamber to reduce the area of said second piston means subjected to said second pressure when said second piston means is seated therein only until said second piston means has begun to move said first and second piston means together with said interconnecting means and to thereafter no longer reduce said area, whereby said second piston means moves said first and second piston means together with said interconnecting means against said friction means with a snap action.

3. In a pressure differential indicator for indicating a rise in a fluid pressure differential across a filter in a fluid system when in normal operation, due only to contamination build up and wherein said indicator includes movably mounted piston means and means for communicating fluid pressures of said system upstream and downstream of said filter to first and second piston surfaces of said piston means which are in opposed force transmitting relationship, the improvement comprising the provision of:

differential means for giving said second piston surface a hydrostatic advantage over said first pistion surface in said opposed force transmitting relationship for normally unbalancing the resultant forces of said pressures on said piston means in favor of that applied by said second surface to hold said piston means in a given first clean filter indicating position under varying system pressures operating with a clean filter condition, said differential means including means for causing movement of said piston means to a second caution contamination filter indicating position only when the resultant forces on said piston means are substantially balanced due to increases in the pressure drop across said filter of a given predetermined increased amount indicative of a predetermined amount of filter contamination warranting replacement of said filter and to a third dirty filter indicating position on further increases in said pressure drop, whereby said piston means is movably responsive relative said second caution position to an increase or decrease in the pressure differential across said filter due only to filter contamination above or below said predetermined increased amount of pressure differential which balances said resultant forces of said pressures on said piston means first and second surfaces, respectively, and

means for giving a visually observable indication of the position of said piston means,

wherein said piston means includes two pistons, each having one of said surfaces in communication with said upstream and downstream pressures, and said differential means comprises the provision of;

interconnecting means between said pistons to provide simultaneous motion therefor and including a pivoted connecting rod extending between said pistons and wherein the lever arm of said rod from its pivot to the piston having said second surface which is exposed to downstream pressure is longer than that relative to the other piston.

4. In a pressure differential indicator for indicating a rise in a fluid pressure differential across a filter in a fluid system when in normal operation, due only to contamination build up and wherein said indicator includes movably mounted piston means and means for communicating fluid pressures of said system upstream and downstream of said filter to first and second piston surfaces of said piston means which are in opposed force transmitting relationship, the improvement comprising the provision of:

differential means for giving said second piston surface a hydrostatic advantage over said first pistion surface in said opposed force transmitting relationship for normally unbalancing the resultant forces of said pressures on said piston means in favor of that applied by said second surface to hold said piston means in a given first clean filter indicating position under varying system pressures operating with a clean filter condition, said differential means including means for causing movement of said piston means to a second caution contamination filter indicating position only when the resultant forces on said piston means are substantially balanced due to increases in the pressure drop across said filter of a given predetermined increased amount indicative of a predetermined amount of filter contamination warranting replacement of said filter and to a third dirty filter indicating position on further increases in said pressure drop, whereby said piston means is movably responsive relative said second caution position to an increase or decrease in the pressure differential across said filter due only to filter contamination above or below said predetermined increased amount of pressure differential which balances said resultant forces of said pressures on said piston means first and second surfaces, respectively;

means for giving a visually observable indication of the position of said piston means; and

means are provided for holding said movably mounted piston means in its system operating position it assumes due to said system pressures upon reduction of said pressures.

5. The improvement in pressure differential indicator of claim 4 wherein said means for holding said piston means comprises friction means interposed between said piston means and the walls of a surrounding chamber within which said piston means is operable.

6. In a pressure differential indicator for indicating a rise in a fluid pressure differential across a filter in a fluid system when in normal operation, due only to contamination build up and wherein said indicator includes moveably mounted piston means and means for communicating fluid pressures of said system upstream and downstream of said filter to first and second piston surfaces, respectively, of said piston means which are in opposed force transmitting relationship in first and second chambers the improvement comprising the provision of:

differential means for giving said second piston surface a mechanical advantage over said first piston surface in said opposed force transmitting relationship for normally unbalancing the resultant forces of said pressures on said piston means in favor of that applied by said second surface under varying system pressures operating with a clean filter condition and by an amount whereby the forces on said piston means are balanced under varying system pressures when the contamination of said filter increases the pressure drop thereacross by a given predetermined increased amount, whereby said piston means is responsive to an increase or decrease in the pressure differential across said filter due only to filter contamination above or below said predetermined increased amount of pressure differential which balances said resultant forces of said pressures on said piston means;

means for giving a visually observable indication of the movement of said piston means;

means for holding said moveably mounted piston means in its system operating position it assumes due to said system pressures upon reduction of said pressures; and

wherein said means for holding said piston means in its system operating position comprises the provision of an assembly of two separate members biased apart and means for engaging the walls of a surrounding chamber within which said piston means is positioned and which is operated to so engage said walls by the said members in their biased apart position and released when said members are subjected to said pressures.

7. The improvement in pressure differential indicator of claim 6 wherein:

spring means are provided between said two separate members for biasing them apart and thereby operating said engaging means, said spring means being selected to hold said members apart under pressure differential across said members up to those of a normal system idle running condition and being compressed to allow movement of said member toward one another when the system pressure increases above said idle condition.

8. The improvement in pressure differential indicator of claim 6 wherein a plurality of indexing grooves are provided in said chamber walls to be engaged by said means for engaging.

9. A pressure differential indicator comprising:

first and second piston means in first and second chambers respectively;

means to subject said first and second piston means to first and second pressures respectively;

interconnecting means extending into each of said first and second chambers and connected between said first and second piston means for requiring that the pressure force produced by said first pressure on said first piston means to enable said first piston means to move said first and second piston means together with said interconnecting means be a predetermined amount larger than the pressure force produced by said second pressure on said second piston means to enable said second piston means to move said first and second piston means together with said interconnecting means; and

a body member of generally elongated cylindrical shape and formed with a pair of openings extending axially inwardly from the opposite ends thereof, said first and second piston means being located one each in each of said axial openings,

said interconnecting means comprising an interconnecting rod secured to the inside ends of each of said first and second piston means and extending through a suitably formed opening in the wall of said body between said first and second piston mean bores,

the overall length of said first and second piston means and interconnecting rod being a predetermined amount larger than the axial length of said body, whereby at least a portion of one or the other of said first and second piston means extends outwardly beyond one of the other ends of said body.

10. The pressure differential indicator of claim 9 comprising:

a protective cover member overlying the end of said body member to which said piston members extend, said cover member being formed of a transparent material.

11. A pressure differential indicator comprising:

first and second piston means,

means to subject said first and second piston means to first and second pressures respectively;

a housing having cylinder means to mount said first and second piston means in a side-by-side tandem arrangement;

interconnecting means between said first and second piston means and including differential force means selectively provided to require that the pressure force produced by said first pressure on said first piston means to enable said first piston means to move said first and second piston means together with said interconnecting means be a predetermined amount larger than the pressure force produced by said second pressure on said second piston means to enable said second piston means to move said first and second piston means together with said interconnecting means,

said interconnecting means comprising a cross beam having each of its ends operatively co-operable with one of said first and second piston means; and

means to pivotally mount said cross beam intermediate its ends in said housing the configurations and locations of said cross beam, said piston means, and the pivot point of said cross beam in said housing being provided so that a portion of one or the other of said first and second piston means is exposed out of said housing at an one instant.

12. The pressure differential indicator of claim 11 comprising:

an adapter member and means to secure said indicator housing to said adapter member,

said pressure subjecting means comprising passageways formed in said adapter member to deliver said first and second pressures to said first and second piston means respectively.

13. The pressure differential indicator of claim 12 comprising:

diaphragm means for each of said first and second piston means, said diaphragm means comprising a bead portion, means to sealingly mount said diaphragm bead portion for each of said piston means in a suitable formed groove at the interface between said indicator housing and said adapter portion, each of said diaphragm portions including an enlarged flexible diaphragm adapted to encase said first and second piston portions, and having doubled over diaphragm portions to permit motion of said piston portions towards and away from said adapter portion while retaining a fluid seal between said indicator portion and said adapter portion.

14. The pressure differential indicator of claim 11 comprising:

said piston means comprising a pair of identical piston members, each of said piston members comprising a formed opening to receive the respective end of said cross beam, said ends of said cross-beam being formed with ball ends, said pivot point of said cross beam on said body member being located a predetermined amount closer to said second piston means, whereby said first piston means is provided with a longer moment arm between said ball end and said pivot point than the moment arm between said pivot point and the ball end of said cross beam cooperable with said second piston means.

15. The pressure differential indicator of claim 11 comprising:

pressure differential indicia provided on the ends of said piston means which are exposed out of said body member.

16. The pressure differential indicator of claim 11 wherein:

said housing comprises a pair of spaced cross walls defining a groove therebetween, said crossbeam being mounted in the groove between said cross walls by a pivot pin extending through said cross walls and a suitably formed opening in said cross beam, and a spring cover member overlying said crosswalls, and adapted to hold the ends of said pivot pin and to close off said groove against the entry of foreign materials therein.

17. A pressure differential indicator comprising:

first and second piston means,

means to subject said first and second piston means to first and second pressures respectively,

interconnecting means between said first and second piston means, and including differential force means selectively provided to require that the pressure force produced by said first pressure on said first piston means to enable said first piston means to move said first and second piston means together with said interconnecting means be a predetermined amount larger than the pressure force produced by said second pressure on said second piston means to enable said second piston means to move said first and second piston means together with said interconnecting means,

a housing means to mount said first and second piston means and said interconnecting means, in said housing;

said first and second pressures comprising the upstream and downstream pressures of a filter member located in a circulating pressurized fluid system, and said means to subject said piston means to said pressures comprising adapter means interposed between said indicator housing and said filter member;

wherein said filter member is of the spin-on type, said adapter means comprising an adapter member having one side for connection to the engine which simulates a normal spin-on filter, and its opposite side for connection to the filter which simulates the normal engine connection, said adapter means further comprising a ring portion surrounding said adapter member to permit rotation of said adapter member therein, and a throat portion for interconnecting said ring portion with said indicator housing and passageway means forming part of said pressure subjecting means formed in said adapter member and said throat portion to tap into the flow of lubricating oil through said adapter member to and from said filter to deliver said pressures to said indicator means, and fluid seals interposed one between said adapter means and engine and another between said adapter means and said filter.

18. A pressure differential indicator comprising:

first and second piston means,

means to subject said first and second piston means to first and second pressures respectively,

interconnecting means between said first and second piston means and including differential force means selectively provided to require that the pressure force produced by said first pressure on said first piston means to enable said first piston means to move said first and second piston means together with said interconnecting measn be a predetermined amount larger than the pressure force produced by said second pressure on said second piston means to enable said second piston means to move said first and second piston means together with said interconnecting means,

a housing means to mount said first and second piston means and said interconnecting means in said housing;

said first and second pressures comprising the upstream and downstream pressures of a filter member located in a circulating pressurized fluid system, and said means to subject said piston means to said pressures comprising adapter means interposed between said indicator housing and said filter member;

said adapter means comprising an adapter body formed integral with said indicator housing, said adapter means further comprising a pair of connector members moveably and sealingly mounted on said adapter body, said pressure subjecting means comprising passageways formed in said connector to tap said indicator into the flow of fluid through said filter member via conduits inter-connecting the ends of said pair of connector members through said filter member.

19. A pressure differential indicator comprising:

first and second piston means,

means to subject said first and second piston means to first and second pressures respectively,

interconnecting means between said first and second piston means and including differential force means selectively provided to require that the pressure force produced by said first pressure on said first piston means to enable said first piston means to move said first and second piston means together with said interconnecting means be a predetermined amount larger than the pressure force produced by said second pressure on said second piston means to enable said second piston means to move said first and second piston means together with said interconnecting means, and a body of generally elongated cylindrical shape comprising a pair of bores extending inwardly towards the opposite ends thereof, said piston means comprising a pair of piston members mounted one in each of said bores, an interconnecting rod extending between said pistons through a suitably formed opening in the wall of said body between said bores and rigidly interconnecting said pistons, the overall length of said pistons and interconnecting rods being longer than the overall length of said body, said first and second pressures both being less than atmospheric pressure and said indicator being exposed to atmospheric pressure on the outside thereof, said first and second piston means each comprising a piston member of stepped construction, and retainer plates mounted in each end of said body for cooperation with the step in said piston members to define the outermost limit of motion of each of said piston members.

20. The pressure differential indicator of claim 19, wherein a larger cross-sectional area of said first piston means is provided as compared to the cross-sectional area of said second piston means, said enlargement of cross-sectional area being a predetermined amount and proportional to the predetermined desired differential pressure at the operating pressures encountered by said indicator.

21. The pressure differential indicator of claim 19 including differential pressure indicia on said first and second piston means on the portions thereof exposed out of said body in one or the other of the positions of said first and second piston means together with said interconnecting means in said body.

22. A pressure differential indicator comprising:

first and second piston means,

means to subject said first and second piston means to first and second pressures respectively,

interconnecting means between said first and second piston means and including differential force means selectively provided to require that the pressure force produced by said first pressure on said first piston means to enable said first piston means to move said first and second means together with said interconnecting means be a predetermined amount larger than the pressure force produced by said second pressure on said second piston means to enable said second piston means to move said first and second piston means together with said interconnecting means, and a body member of generally elongated cylindrical shape formed with a pair of bores extending inwardly toward the opposite ends thereof, said piston means comprising first and second piston members located one in each of said bores, a connecting rod interconnecting said piston members and extending through a suitably formed opening in the wall of said body member between the inner ends of said bores, connection means to connect the end of said connecting rod to said piston members, said connecting means comprising a plurality of resilient fingers each having an overlapping edge, and a suitably formed stepped opening in the inner ends of said piston members, whereby said ends of said connecting rod may be thrust into said openings and said fingers will first compress and then expand to lock said connecting rod to said piston members.

23. A filter contamination indicator for a fluid system including a filter and operating at various fluid pressures such that the pressure drop across the filter when the latter is clean varies in a predeterminable manner proportionate to system operating pressures, said indicator comprising:

movably mounted piston means and means for communicating fluid pressures of said system upstream and downstream of said component to first and second piston surfaces respectively;

means for mounting said first and second piston surfaces in opposed force transmitting relationship within a housing, said piston means including first and second piston portions connected to said first and second surfaces respectively and in telescoping relation to each other,

means for providing said second piston surface a mechanical advantage over said first piston surface whereby the force exerted on said second piston surface is larger than that on said first piston surface under their respective changing pressures during system operation with a clean filter, the forces of said piston surfaces are balanced at a predetermined value of increased pressure drop across said filter due to contamination build up and the force on said first surface exceeds that on said second surface when pressure drop across said filter due to contamination build up exceeds said predetermined value;

means for biasing said telescoping piston portions away from each other; and

means operated on movement of said piston portions away from each other under said bias when system pressure is relieved for holding said moveably mounted piston means in the position it assumed under the action of said system pressures.