WO1982002622A1 - A temperature compensated switch for monitoring a filter bypass valve - Google Patents

A temperature compensated switch for monitoring a filter bypass valve Download PDF

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Publication number
WO1982002622A1
WO1982002622A1 PCT/US1981/000107 US8100107W WO8202622A1 WO 1982002622 A1 WO1982002622 A1 WO 1982002622A1 US 8100107 W US8100107 W US 8100107W WO 8202622 A1 WO8202622 A1 WO 8202622A1
Authority
WO
WIPO (PCT)
Prior art keywords
piston
switch
fluid
wax motor
movable
Prior art date
Application number
PCT/US1981/000107
Other languages
French (fr)
Inventor
Joe E Fuzzell
Original Assignee
Joe E Fuzzell
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Joe E Fuzzell filed Critical Joe E Fuzzell
Priority to PCT/US1981/000107 priority Critical patent/WO1982002622A1/en
Publication of WO1982002622A1 publication Critical patent/WO1982002622A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/74—Switches in which only the opening movement or only the closing movement of a contact is effected by heating or cooling
    • H01H37/76—Contact member actuated by melting of fusible material, actuated due to burning of combustible material or due to explosion of explosive material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
    • B01D35/14—Safety devices specially adapted for filtration; Devices for indicating clogging
    • B01D35/143—Filter condition indicators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
    • B01D35/14—Safety devices specially adapted for filtration; Devices for indicating clogging
    • B01D35/147—Bypass or safety valves
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/247—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow the switch being of the reed switch type

Definitions

  • This invention relates generally to a switch and, more particularly, to a switch for monitoring a filter bypass valve.
  • Fluidic systems such as lubricating oil or fuel systems use filters in a fluid line to remove contaminants carried by the fluid.
  • a filter which becomes clogged or plugged by contaminants will result in a decrease in the fluid flow.
  • a reduction in fluid flow through the filter also can occur during cold fluid operating conditions when the viscosity of the fluid is high. ⁇
  • a bypass valve can be a spool valve having a spool which is moved to open the valve and to bypass the fluid around the filter in response to a predetermined fluid pressure differential across the filter.
  • a switch for monitoring the open and closed states of the bypass valve has been employed to produce a signal when the valve is open or in the bypass mode.
  • the switch may have electrical contacts and a pin or piston which is operatively coupled to
  • a problem with such a prior switch is that it cannot distinguish between a bypass mode due to a plugged filter or a bypass mode due to the high viscosity of the fluid at cold fluid temperatures. In either mode, the bypass valve will be open, resulting in the switch generating the signal. This is disadvantageous since it usually is of primary importance to know that the bypass valve is open due to a plugged filter which should be cleaned or replaced, rather than being open due to a viscous fluid.
  • the present invention is directed to overcoming one or more of the problems as set forth above.
  • a switch for monitoring a fluid bypass valve has a movable member adapted to be operatively coupled to the fluid bypass valve, means for moving the movable member towards the fluid bypass valve, and means for generating a signal in response to a predetermined movement of the movable member, the improvement comprising means for sensing the temperature of the fluid and inhibiting movement of the movable member in response to a preselected temperature of the fluid.
  • a prior filter bypass monitoring switch in producing such a signal, cannot distinguish between bypass modes due to a plugged filter or viscous fluid, and has a piston which continually follows the bypass valve, causing undue piston wear.
  • the switch of the present invention has a fluid temperature sensor which inhibits movement of its movable member only during cold fluid operating conditions below the threshold temperature when the bypass valve can be in a bypass mode due to viscous fluid, thereby distinguishing between the two bypass modes and reducing wear of the movable member.
  • Fig. 1 is a block diagram of a fluidic system.
  • Fig. 2 is a cross-section of an embodiment of the present invention.
  • Fig. 1 shows a fluidic system 10 having a fluid filter 12 which filters fluid being received at an inlet 14 and flowing out an outlet 16.
  • a fluid bypass valve 18 is coupled in parallel across filter 12 to transfer fluid from inlet 14 to outlet 16, bypassing filter 12, in response to a ' predetermined differential fluid pressure across filter 12.
  • Such a differential fluid pressure can occur typically under two conditions. One condition is when the filter is plugged, causing a higher pressure at the inlet 14 in relation to the outlet 16. The other is during cold fluid operating conditions when the fluid is viscous, causing a similar differential fluid pressure across filter 12.
  • Bypass valve 18 has a movable control member 20 which responds to this differential fluid pressure to open valve 18 and transfer fluid from inlet 14 to outlet 16, bypassing filter 12.
  • Bypass valve 18 can be, for example, a spool valve or a check valve. If, for example, bypass valve 18 is a spool valve, then control member 20 can be spool spring biased to a closed state of valve 18.
  • a switch 22 of the present invention can be operatively coupled to bypass valve 18, particu ⁇ larly control member 20, to monitor the bypass valve 18. Switch 22 is constructed to distinguish between a bypass mode of valve 18 due to a plugged filter 12 and a bypass mode of valve 18 due to viscous fluid at cold fluid temperatures.
  • switch 22 has a housing 24 which supports a movable member 26.
  • movable member 26 can be a hollow piston 28 that is slidable along housing 24 and that has an end 30 which can be positioned or operatively coupled adjacent control member 20.
  • Piston 28 has at least one aperture 32 through which some fluid can flow into a chamber 34 for reasons to be described, and is retained in housing 24 by a retainer 36.
  • a means 38 for moving the movable member 26, specifically piston 28, is supported in housing 24.
  • Means 38 includes a washer 40 secured to piston 28 and a spring 42 disposed between washer 40 and housing 24.
  • Spring 42 is disposed to bias or move washer 40 and, hence, piston 28, to the right, as viewed in Fig. 2, i.e., towards or against control member 20 to follow the travel of member 20.
  • the aperture 32 produces a fluid path to prevent any differential pressure from developing across piston 28, which differential pressure otherwise might prevent spring 42 from displacing piston 28.
  • Switch 22 also includes means 44 for generat- ing a signal in response to a predetermined movement of the piston 28 to the right as viewed in Fig. 2, i.e., in response to movement of the piston 28 a certain distance.
  • Signal generating means 44 includes a magnet 46 that is supported by and movable with piston 2-8, and that has north and south poles as shown.
  • a magnetically operated switch such as a normally open reed switch 48 is disposed in a bore 50 of housing 24 and has an electrical connection 52 which can lead to an alarm such as a light (not shown) .
  • magnet 46 is in a position to close reed switch 48 to prevent generating the alarm signal. Should the piston 28 be moved a sufficient distance to the right by spring 42 and washer 40, magnet 46 will be sufficiently displaced so that reed switch 48 will open to generate the alarm signal.
  • Switch 22 also includes means 54 for sensing the temperature of the fluid and inhibiting movement of the piston 28 in response to the fluid temperature being below a preselected temperature or temperature threshold.
  • Means 54 includes wax motor 56 • that has a piston 58.
  • a plug 60 is secured to the housing 24 by a screw and lock washer assembly 61.
  • Piston 58 is coupled to or received by plug 60 in a notch 62.
  • Means 64 such as an extension spring 66, is disposed between wax motor 56 and housing 24 to bias wax motor 56 to the left, as viewed in Fig. 2, i.e., towards plug 60 and against the bias of spring 42 by acting on washer 40.
  • wax motor 56 When the temperature is below the tem ⁇ perature threshold, e.g., 125°F, wax motor 56 will be in the position shown in Fig. 2. When the tem ⁇ perature is above the temperature threshold, the wax in wax motor 56 will melt, resulting in the wax motor 56 moving to the right in hollow piston 28 as piston 58 remains stationary, extending spring 66. As wax motor 56 moves to the right, spring 42 becomes extended to move washer 40 and, hence, piston 28 to the right.
  • the tem ⁇ perature threshold e.g., 125°F
  • the fluidic system 10 can be part of a lubricating circuit of a vehicle such as an earth- working vehicle.
  • Three operating conditions will be discussed to explain the operation of switch 22, including a cold fluid operating condition, a warm fluid operating condition in which filter 12 is not plugged and a warm fluid operating condition in which filter 12 is plugged.
  • a differential fluid pressure can build up across filter 12, causing control member 20 to move to the right as viewed in Fig. 1 and Fig. 2.
  • bypass valve 18 opens to conduct fluid from inlet 14 to outlet 16.
  • Wax motor 56 senses the cold fluid temperature and remains in the position shown in Fig. 2 so that reed switch 48 remains closed and
  • switch 22 can distinguish between bypass modes occurring due to a plugged filter 12 at warm fluid operating conditions and viscous fluid at cold fluid operating temperatures.
  • the wax motor 56 inhibits movement of the piston 28 during cold fluid operating temperatures, thereby limiting wear and increasing the lifetime of piston 28.
  • wax motor 56 is highly accur-

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

A filter bypass monitoring switch (22) includes a housing (24), a piston (28) slidable in the housing (24) and operatively coupled to a movable control member (20) of a bypass valve (18), a spring (42) to bias the piston (28) to follow the movable control member (20), a wax motor (56) which senses fluid temperature and is biased to inhibit movement of the piston (28) below a temperature threshold, and a magnetic circuit (44) to generate an alarm signal. Unlike prior switches, the present switch (22) uses the wax motor (56) to distinguish between filter bypass modes occurring during cold fluid operating conditions when the fluid is viscous and warm fluid operating conditions when the filter is plugged.

Description

Description
A Temperature Compensated Switch For Monitoring A Filter Bypass Valve
Technical Field This invention relates generally to a switch and, more particularly, to a switch for monitoring a filter bypass valve.
Background Art
Fluidic systems such as lubricating oil or fuel systems use filters in a fluid line to remove contaminants carried by the fluid. A filter which becomes clogged or plugged by contaminants will result in a decrease in the fluid flow. A reduction in fluid flow through the filter also can occur during cold fluid operating conditions when the viscosity of the fluid is high. ~
A loss of lubricant due to reduced oil flow or a loss of power due to reduced fuel flow will have obvious adverse consequences. Consequently, fluidic systems also have bypass vlaves which ensure fluid flow in the event of a plugged filter or highly viscous fluid during cold fluid operating conditions. Typically, a bypass valve can be a spool valve having a spool which is moved to open the valve and to bypass the fluid around the filter in response to a predetermined fluid pressure differential across the filter.
A switch for monitoring the open and closed states of the bypass valve has been employed to produce a signal when the valve is open or in the bypass mode. The switch may have electrical contacts and a pin or piston which is operatively coupled to
- L> __Λ* ~- and moves with the spool. When the spool is moved to the open or bypass position, the piston is moved to open the contacts to generate the signal. "When the spool is returned to the closed position, the piston follows the spool to close the contacts and, thereby, turn off the signal.
A problem with such a prior switch is that it cannot distinguish between a bypass mode due to a plugged filter or a bypass mode due to the high viscosity of the fluid at cold fluid temperatures. In either mode, the bypass valve will be open, resulting in the switch generating the signal. This is disadvantageous since it usually is of primary importance to know that the bypass valve is open due to a plugged filter which should be cleaned or replaced, rather than being open due to a viscous fluid.
Another problem with the prior switch is that its piston will follow or move with the spool at all times that the bypass valve changes between open and closed states. Consequently, the piston is continually subjected to wear, which can reduce its lifetime.
The present invention is directed to overcoming one or more of the problems as set forth above.
Disclosure of the Invention
In one aspect of the present invention, a switch for monitoring a fluid bypass valve has a movable member adapted to be operatively coupled to the fluid bypass valve, means for moving the movable member towards the fluid bypass valve, and means for generating a signal in response to a predetermined movement of the movable member, the improvement comprising means for sensing the temperature of the fluid and inhibiting movement of the movable member in response to a preselected temperature of the fluid.
A prior filter bypass monitoring switch, in producing such a signal, cannot distinguish between bypass modes due to a plugged filter or viscous fluid, and has a piston which continually follows the bypass valve, causing undue piston wear. The switch of the present invention has a fluid temperature sensor which inhibits movement of its movable member only during cold fluid operating conditions below the threshold temperature when the bypass valve can be in a bypass mode due to viscous fluid, thereby distinguishing between the two bypass modes and reducing wear of the movable member.
Brief Description of the Drawings
Fig. 1 is a block diagram of a fluidic system.
Fig. 2 is a cross-section of an embodiment of the present invention.
Best Mode for Carrying Out the Invention
Fig. 1 shows a fluidic system 10 having a fluid filter 12 which filters fluid being received at an inlet 14 and flowing out an outlet 16. A fluid bypass valve 18 is coupled in parallel across filter 12 to transfer fluid from inlet 14 to outlet 16, bypassing filter 12, in response to a' predetermined differential fluid pressure across filter 12. Such a differential fluid pressure can occur typically under two conditions. One condition is when the filter is plugged, causing a higher pressure at the inlet 14 in relation to the outlet 16. The other is during cold fluid operating conditions when the fluid is viscous, causing a similar differential fluid pressure across filter 12.
Bypass valve 18 has a movable control member 20 which responds to this differential fluid pressure to open valve 18 and transfer fluid from inlet 14 to outlet 16, bypassing filter 12. Bypass valve 18 can be, for example, a spool valve or a check valve. If, for example, bypass valve 18 is a spool valve, then control member 20 can be spool spring biased to a closed state of valve 18. A switch 22 of the present invention can be operatively coupled to bypass valve 18, particu¬ larly control member 20, to monitor the bypass valve 18. Switch 22 is constructed to distinguish between a bypass mode of valve 18 due to a plugged filter 12 and a bypass mode of valve 18 due to viscous fluid at cold fluid temperatures. ,
As illustrated in Fig. 2, switch 22 has a housing 24 which supports a movable member 26. As an example, movable member 26 can be a hollow piston 28 that is slidable along housing 24 and that has an end 30 which can be positioned or operatively coupled adjacent control member 20. Piston 28 has at least one aperture 32 through which some fluid can flow into a chamber 34 for reasons to be described, and is retained in housing 24 by a retainer 36.
A means 38 for moving the movable member 26, specifically piston 28, is supported in housing 24. Means 38 includes a washer 40 secured to piston 28 and a spring 42 disposed between washer 40 and housing 24. Spring 42 is disposed to bias or move washer 40 and, hence, piston 28, to the right, as viewed in Fig. 2, i.e., towards or against control member 20 to follow the travel of member 20. The aperture 32 produces a fluid path to prevent any differential pressure from developing across piston 28, which differential pressure otherwise might prevent spring 42 from displacing piston 28.
Switch 22 also includes means 44 for generat- ing a signal in response to a predetermined movement of the piston 28 to the right as viewed in Fig. 2, i.e., in response to movement of the piston 28 a certain distance. Signal generating means 44 includes a magnet 46 that is supported by and movable with piston 2-8, and that has north and south poles as shown. A magnetically operated switch such as a normally open reed switch 48 is disposed in a bore 50 of housing 24 and has an electrical connection 52 which can lead to an alarm such as a light (not shown) . As shown in Fig. 2, magnet 46 is in a position to close reed switch 48 to prevent generating the alarm signal. Should the piston 28 be moved a sufficient distance to the right by spring 42 and washer 40, magnet 46 will be sufficiently displaced so that reed switch 48 will open to generate the alarm signal.
Switch 22 also includes means 54 for sensing the temperature of the fluid and inhibiting movement of the piston 28 in response to the fluid temperature being below a preselected temperature or temperature threshold. Means 54 includes wax motor 56 • that has a piston 58. A plug 60 is secured to the housing 24 by a screw and lock washer assembly 61. Piston 58 is coupled to or received by plug 60 in a notch 62. Means 64, such as an extension spring 66, is disposed between wax motor 56 and housing 24 to bias wax motor 56 to the left, as viewed in Fig. 2, i.e., towards plug 60 and against the bias of spring 42 by acting on washer 40.
When the temperature is below the tem¬ perature threshold, e.g., 125°F, wax motor 56 will be in the position shown in Fig. 2. When the tem¬ perature is above the temperature threshold, the wax in wax motor 56 will melt, resulting in the wax motor 56 moving to the right in hollow piston 28 as piston 58 remains stationary, extending spring 66. As wax motor 56 moves to the right, spring 42 becomes extended to move washer 40 and, hence, piston 28 to the right.
Industrial Applicability
The fluidic system 10 can be part of a lubricating circuit of a vehicle such as an earth- working vehicle. Three operating conditions will be discussed to explain the operation of switch 22, including a cold fluid operating condition, a warm fluid operating condition in which filter 12 is not plugged and a warm fluid operating condition in which filter 12 is plugged. During cold fluid operating conditions when the lubricating fluid is viscous, e.g., below 125°F, a differential fluid pressure can build up across filter 12, causing control member 20 to move to the right as viewed in Fig. 1 and Fig. 2. Conse- quently, bypass valve 18 opens to conduct fluid from inlet 14 to outlet 16. Wax motor 56 senses the cold fluid temperature and remains in the position shown in Fig. 2 so that reed switch 48 remains closed and
OMPI the alarm signal is not generated. In other words, piston 28 does not move to the right to follow the movement of control member 20.
During warm fluid operating conditions in which filter 12 is not plugged, the differential fluid pressure across filter 12 will not build up so that bypass valve 18 remains closed with control member 20 adjacent piston 28. Wax motor 56 senses the warm fluid temperature and moves to the right as shown in Fig. 2. Spring 42 will provide a force tending to move piston 28 to the right; however, the control member 20 overcomes this force to act on piston 28 and prevents piston 28 from moving to the right. Therefore, magnet 46 remains in the position shown and the alarm signal is not generated.
During warm fluid operating conditions in which filter 12 is plugged, the differential fluid pressure across filter 12 will build up so that by¬ pass valve 18 opens, control member 20 being moved to the right. Wax motor 56 senses the warm fluid temperature and moves to the right. Spring 42 can now move piston 28 to the right to follow control member 20. Consequently, magnet 46 is moved sufficiently to the right to open reed switch 48 and generate the alarm signal.
In summary, switch 22 can distinguish between bypass modes occurring due to a plugged filter 12 at warm fluid operating conditions and viscous fluid at cold fluid operating temperatures. The wax motor 56 inhibits movement of the piston 28 during cold fluid operating temperatures, thereby limiting wear and increasing the lifetime of piston 28.
Furthermore, wax motor 56 is highly accur-
Figure imgf000009_0001
ate to about + or - 1% of the temperature threshold for which it is designed. Also, because of the north-south orientation of magnet.46 in relation to reed switch 48, vibration, which might move piston 28 a short distance in housing 24 from the Fig. 2 position, normally will not move magnet 46 so far as to cause reed switch 48 to open and produce a false warning signal. Still furthermore, with reed switch 48 being normally open, a fail-safe circuit is provided. For example, with magnet 46 in the position shown and reed switch 48 closed, a loose connection 52 will open the circuit to generate the alarm signal though this would not result from a plugged filter 12.
Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.

Claims

Claims
1. In a switch (22) for monitoring a fluid bypass valve (18), the switch (22) having a movable member (26) adapted to be operatively coupled to the fluid bypass valve (18) , means (38) for moving said movable member (26) towards the fluid bypass valve (18) , and means (44) for generating a signal in response to a predetermined movement of said movable member (26) , the improvement comprising: means (54) for sensing the temperature of the fluid and inhibiting movement of said movable member (26) in response to the fluid tem¬ perature being below a preselected temperature.
2. A switch (22) , according to claim 1, wherein said temperature sensing and inhibiting means (54) includes a wax motor (56).
3. A switch (22) , according to claim 1, wherein said temperature sensing and inhibiting means (54) includes: a) a wax motor (56) having a piston (58) and being movable in relation to said movable member (26) ; b) a fixed plug (60) receiving said piston- (58) ; and c) means (64) for biasing said wax motor (56) towards said fixed plug (60) and against said moving means (38) .
4. A switch (22) , according to claim 1, wherein said means (44) for generating a signal includes a magnet (46) and a magnetically-operated switch (48) being controlled by said magnet (46).
5. A switch (22), according to claim 4, wherein said magnetically-operated switch (48) is a reed switch.
6. A switch (22) , according to claim 1, wherein said movable member (26) includes a piston (28).
7. A switch (22) , according to claim 6, wherein said means (38) for moving includes first means (40, 42) for biasing said piston towards the bypass valve (18) .
8. A switch (22) , according to claim 7, wherein said piston (28) of said movable member (26) is hollow and said temperature sensing and inhibiting means (54) includes: a) a wax motor (56) having a piston (58) and being movable within said hollow piston (28) ; b) a fixed plug (60) receiving said piston (58) of said wax motor (56) ; and c) second means (64) for biasing said wax motor (56) towards said fixed plug (60) and against the bias of said first biasing means (40, 42).
OMPI
9. A switch (22) for monitoring a fluid bypass valve (18) having a movable control member (20) , comprising: a) a housing (24) ; b) a piston (28) movably supported in said housing (24) and adapted to be operatively coupled to the movable control member (20) ; c) first biasing means (38) for moving said piston (28) towards the movable control member (20); d) wax motor means (54) for sensing the temperature of the fluid and inhibiting movement of said piston (28) in response to the fluid being below a preselected temperature; and e) magnetic means (44) for generating a signal in response to moving said piston (28) a preselected distance towards the movable control member (20) .
10. A switch (22), according to claim 9, wherein said wax motor means (54) includes: a) a wax motor (56) having a piston (58) and being movable in relation to said movably supported piston (28); b) a plug (60) secured to said housing (24) and receiving said piston (58) of said wax motor (56) ; and c) second biasing means {64 ) for moving said wax motor (56) towards said plug (60) and against the bias of said first biasing means (38).
OMPI
11. A switch (22), according to claim 9, wherein said magnetic means (44) includes: a) a magnet (46) supported on said movably supported piston (28) ; and b) magnetically-operated switch (48) supported by said housing (24) and being controlled by said magnet (46).
12. A switch (22), according to claim 11, wherein said magnetically-operated switch (48) is a reed switch.
OMP
13. A switch (22) for monitoring a fluid bypass valve (18) having a movable control member (20) , comprising: a) a housing (24) ; b) a hollow piston (28) having one end
(30) adapted to be operatively coupled to the movable control member (20) and being slidably movable in said housing (24) ; c) first spring means (38) for biasing said hollow piston (28) towards the movable control member (20) ; d) a plug (60) secured to said housing (24) and being positioned in said hollow piston (28) ; e) a wax motor (56) having a piston (58) received by said plug (60) and being slidably movable in said hollow piston (28) , said wax motor (56) being adapted to sense the temperature of .the fluid; f) second spring means (64) for biasing said wax motor (56) towards said plug (60) and against the bias of said first spring means (38) and inhibiting movement of said hollow piston (28) in response to the sensed temperature being below a preselected value; g) a magnet (46) supported by said hollow piston. (24) ; and h) a reed switch (48) supported by said housing (24) and being controlled by said magnet (46).
PCT/US1981/000107 1981-01-19 1981-01-19 A temperature compensated switch for monitoring a filter bypass valve WO1982002622A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US1981/000107 WO1982002622A1 (en) 1981-01-19 1981-01-19 A temperature compensated switch for monitoring a filter bypass valve

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
WOUS81/00107810119 1981-01-19
PCT/US1981/000107 WO1982002622A1 (en) 1981-01-19 1981-01-19 A temperature compensated switch for monitoring a filter bypass valve

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4850966A (en) * 1986-02-26 1989-07-25 Hoechst Aktiengesellschaft Device for the administration of medicament suspensions
WO1991006357A1 (en) * 1989-10-31 1991-05-16 Le Bozec Et Gautier Clogging indicator
FR2659141A1 (en) * 1990-03-01 1991-09-06 Lebozec & Gautier Clogging indicator
WO2006032259A1 (en) * 2004-09-23 2006-03-30 Mahle Filtersysteme Gmbh Fuel filter of an internal combustion engine provided with a reserve filter element
ITUB20161064A1 (en) * 2016-02-25 2017-08-25 Ufi Filters Spa Delayed-action bypass valve

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1095382A (en) * 1914-05-05 Axel Valdemar Clorius Alarm press-button contact.
US2764027A (en) * 1954-04-19 1956-09-25 Otto Walter Thermal fuse
US3431375A (en) * 1967-03-06 1969-03-04 Eldorado Tool & Mfg Corp Hydraulic flow monitoring device
US3915236A (en) * 1974-03-22 1975-10-28 Gerhardt C Stichling Safety device
US4169254A (en) * 1977-12-27 1979-09-25 Corken International Corporation Thermally activated emergency electric switch
US4213021A (en) * 1979-01-19 1980-07-15 Aeroquip Corporation Indicating check valve

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1095382A (en) * 1914-05-05 Axel Valdemar Clorius Alarm press-button contact.
US2764027A (en) * 1954-04-19 1956-09-25 Otto Walter Thermal fuse
US3431375A (en) * 1967-03-06 1969-03-04 Eldorado Tool & Mfg Corp Hydraulic flow monitoring device
US3915236A (en) * 1974-03-22 1975-10-28 Gerhardt C Stichling Safety device
US4169254A (en) * 1977-12-27 1979-09-25 Corken International Corporation Thermally activated emergency electric switch
US4213021A (en) * 1979-01-19 1980-07-15 Aeroquip Corporation Indicating check valve

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4850966A (en) * 1986-02-26 1989-07-25 Hoechst Aktiengesellschaft Device for the administration of medicament suspensions
WO1991006357A1 (en) * 1989-10-31 1991-05-16 Le Bozec Et Gautier Clogging indicator
US5188728A (en) * 1989-10-31 1993-02-23 Le Bozec Et Gautier Clogging display with shape memory alloy spring actuator
FR2659141A1 (en) * 1990-03-01 1991-09-06 Lebozec & Gautier Clogging indicator
WO2006032259A1 (en) * 2004-09-23 2006-03-30 Mahle Filtersysteme Gmbh Fuel filter of an internal combustion engine provided with a reserve filter element
ITUB20161064A1 (en) * 2016-02-25 2017-08-25 Ufi Filters Spa Delayed-action bypass valve
WO2017145060A1 (en) * 2016-02-25 2017-08-31 Ufi Filters S.P.A. Delayed action bypass valve
CN109069961A (en) * 2016-02-25 2018-12-21 Ufi过滤股份公司 Delay voltage by-passing valve
CN109069961B (en) * 2016-02-25 2020-10-16 Ufi过滤股份公司 Delay action by-pass valve

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