Differential pressure-responsive signalling device and a filter assembly having same

Claim 2

A differential pressure-responsive signalling device comprising, in combination, a housing having first and second fluid passaGes therein communicating with opposite sides of a removable fluid permeable means any blocking of which increases the pressure differential between the passages; differential pressure-responsive signalling means movably mounted in the housing in a position to sense a pressure differential across the fluid permeable means between the first and second passages and adapted to move in indicating response to a predetermined pressure differential therebetween; and reciprocable locking means operatively associated with the signalling means and movable between first and second positions in the first position engaging and retaining the signalling means in an indicating position, and in the second position releasing the signalling means to return to a nonindicating position, said locking means being responsive to movement of the fluid permeable means from its position to release the signalling means.

Claim 3

A differential pressure-responsive signalling device in accordance with claim 1, in which the locking means comprises detent means operative associated with the signalling means, and linkage means operatively connecting the detent means with the fluid permeable means.

Claim 4

A differential pressure-responsive signalling device in accordance with claim 1, in which the locking means is spring-biased against the fluid permeable means.

Claim 5

A differential pressure-responsive signalling device in accordance with claim 1, in which the signalling means has a shaft extending therefrom and in which the locking means is associated with the shaft.

Claim 6

A differential pressure-responsive signalling device in accordance with claim 4, in which the locking means comprises a retainer cap on the shaft and a catch means mounted in the housing for engaging the cap so as to retain the shaft.

Claim 7

A differential pressure-responsive signalling device in accordance with claim 4, in which the locking means includes a spring loaded detent means mounted on the shaft.

Claim 8

A differential pressure-responsive signalling device in accordance with claim 1, in which the pressure-responsive signalling device comprises a magnetic pressure indicator.

Claim 9

A differential pressure-responsive signalling device in accordance with claim 1, in which the pressure-responsive signalling device comprises a magnetic pressure switch.

Claim 10

A filter assembly comprising, in combination, a housing, having an inlet and an outlet, and a chamber communicating with the inlet and the outlet and adapted to enclose a filter element therein in position in the line of flow from the inlet to the outlet such that flow from the inlet to the outlet passes through the filter element; differential pressure-responsive signalling device associated with the housing and communicating with the upstream and downstream sides of the filter element so as to be exposed to a pressure differential thereacross and signal whenever the differential pressure across the filter exceeds a predetermined amount; and locking means operatively associated with the differential responsive signalling device and being reciprocably movable between first and second positions so as to engage at least a portion of said device and retain said device in signalling position when in its first position and release the device when in its second position, said locking means extending into the chamber in a position to operatively engage the filter element, and being responsive to the removal of the filter element from its position in the chamber so as to move to its second position and release said signalling device.

Claim 11

A filter assembly comprising, in combination, a housing, having an inlet and an outlet, and a chamber communicating with the inlet and the outlet and adapted to enclose a filter element therein in position in the line of flow from the inlet to the outlet such that flow from the inlet to the outlet passes through the filter element; differential pressure-responsive signalling device associated with the housing and communicating with the upstream and downstream sides of the filter element so as to be exposed to a pressure differential thereacross and signal whenever the differential pressure across the filter exceeds a predetermined amount; and locking means operatively associated with the differential responsive signalling device and being reciprocably movable between first and second positions so as to engage at least a portion of said device and retain said device in signalling position when in its first position and release the device when in its second position, said locking means extending into the chamber in a position to operatively engage the filter element, and being responsive to the removal of the filter element from its position in the chamber so as to move to its second position and release said signalling device.

Claim 12

A filter assembly in accordance with claim 9, in which the housing has a head and bowl portion and in which the filter element is cylindrical and mounted in the bowl portion.

Claim 13

A filter assembly in accordance with claim 9, in which the locking means comprises detent means, and retaining means adapted to engage and hold the detent means, and in which one of said detent and retaining means is carried on a movable portion of the differential pressure-responsive sigNalling device, and the other is associated with the filter element.

Claim 14

A filter assembly in accordance with claim 11, in which the means associated with the filter element comprises a retainer formed on an end cap of the filter.

Claim 15

A filter assembly in accordance with claim 11, in which the means associated with the filter element is associated therewith by means of a mechanical linkage mechanism.

Claim 16

A filter assembly in accordance with claim 9, in which the signalling means is a differential pressure indicator.

Claim 17

A filter assembly in accordance with claim 9, in which the signalling device is a switch.

Claim 18

A filter assembly in accordance with claim 14, in which the differential pressure indicator comprises a housing divided into two noncommunicating portions by a partition, a magnetic pressure-responsive piston assembly movably mounted in the housing on a side of the partition which communicates with the filter element, and said piston assembly being movable towards and away from the partition; and a magnetic indicating assembly mounted on the opposite side of the partition.

Claim 19

A filter assembly in accordance with claim 9, including thermally responsive means for engaging the locking means and preventing it from retaining the signalling device in its signalling position whenever a temperature is below a predetermined minimum.

Claim 20

A filter assembly in accordance with claim 9, in which the filter assembly has a relief valve for bypassing flow passed the filter element.

Claim 21

A filter assembly in accordance with claim 18, including a reserve filter element mounted in the housing in a position so as to receive flow from the inlet when the relief valve opens.

Claim 22

A filter assembly, comprising, in combination, a housing having an inlet and an outlet, a chamber in the housing communicating with the inlet and the outlet; a filter element mounted in the chamber in a position such that flow from the inlet to the outlet passes through the filter element; a magnetic differential pressure signalling device associated with the housing in a manner so as to be exposed to the pressure differential across the filter element; said magnetic signalling device comprising a housing, a partition in the housing dividing into two noncommunicating portions; a magnetic differential pressure responsive piston on one side of the partition; passages in the signalling device housing connecting opposite sides of the piston with the upstream and downstream sides of the filter element so that the piston is exposed to the differential pressure across the filter element; bias means holding the piston in a first position; signal means on the opposite side of the partition from the piston movable toward and away from the partition in response to movement of the magnetic piston on the opposite side of the partition from its first to its second positions to signal that a predetermined pressure differential across the filter element exists; detent means mounted for movement with the magnetic piston assembly; retaining means operatively associated with the filter element and positioned to engage and retain the detent means when the piston is in its second position, said retaining means being responsive to the removal of the filter from its position in the housing so as to release the detent means whereby the retainer holds the magnetic piston in said second position until it is released by movement of the filter element.

Claim 23

A filter assembly, comprising, in combination, a housing having an inlet and an outlet, a chamber in the housing communicating with the inlet and the outlet; a filter element mounted in the chamber in a position such that flow from the inlet to the outlet passes through the filter element; a magnetic differential pressure signalling device associated with the housing in a manner so as to be exposed to the pressure differential across the filter element; said magnetic signalling device comprising a housing, a partition in the housing dividing into two noncommunicating portions; a magnetic differential pressure responsive piston on one side of the partition; passages in the signalling device housing connecting opposite sides of the piston with the upstream and downstream sides of the filter element so that the piston is exposed to the differential pressure across the filter element; bias means holding the piston in a first position; signal means on the opposite side of the partition from the piston movable toward and away from the partition in response to movement of the magnetic piston on the opposite side of the partition from its first to its second positions to signal that a predetermined pressure differential across the filter element exists; detent means mounted for movement with the magnetic piston assembly; retaining means operatively associated with the filter element and positioned to engage and retain the detent means when the piston is in its second position, said retaining means being responsive to the removal of the filter from its position in the housing so as to release the detent means whereby the retainer holds the magnetic piston in said second position until it is released by movement of the filter element.

Claim 24

A filter assembly in accordance with claim 20 in which the detent means comprises a retainer cap on the end of a shaft extending from the piston.

Claim 25

A filter assembly in accordance with claim 20, in which the detent means comprises a spring loaded detent mounted on an extending portion of the piston.

Claim 26

A filter assembly in accordance with claim 20, in which the retainer is formed on an end cap of the filter element.

Claim 27

A filter assembly in accordance with claim 20, in which the retainer comprises a spring loaded catch, and a spring loaded linkage meAns extending into the housing in a position to engage the filter element such that when the filter element is moved from its position in the housing the spring loaded linkage releases the catch means.

Claim 28

A filter assembly in accordance with claim 24, including a cam surface on the linkage for releasing the spring loaded catch.