Fluid flow restriction indicator

Abstract

An indicator suitable for signaling restricted flow of a fluid through a filter mounted in a filter indicator includes a housing having an inner cavity. A diaphragm disposed within the housing separates the inner cavity into first and second chambers and deflects from a neutral position in response to applied pressures within the first and second chambers. A tab assembly opposite the diaphragm includes a spring-loaded flag moveable from a first position within the housing to a second position outside the housing. A pin operably coupled to the diaphragm holds the spring-loaded flag within the housing when the diaphragm is in the neutral position. In response to the diaphragm being deflected sufficiently from the neutral position to release the pin, the spring-loaded flag travels to the second position outside of the housing, thereby indicating a restrictive flow condition for the filter.

1 . An indicator suitable for signaling restricted flow of a fluid through a filter mounted in a filter assembly, the indicator comprising:
 a housing having an inner cavity;   a deflectable diaphragm disposed within the housing and separating the inner cavity into first and second chambers with a generally fluid-tight seal, wherein the first chamber is adapted to be in fluid communication with the filter assembly, wherein the diaphragm is deflectable from a neutral position in response to applied pressures within the first and second chambers;   a tab assembly having a hole through the tab assembly, the tab assembly including a flag moveable along a first axis from a first position wherein the flag is within the housing and a second position wherein the flag extends from the housing, the tab assembly opposite the diaphragm from the first chamber;   a pin operably coupled to the diaphragm and protruding along a second axis from the diaphragm into the hole and through the tab assembly when the diaphragm is in at least the neutral position, wherein the second axis is nonparallel to the first axis; and   wherein movement of the flag from the first position to the second position is actuated in response to the diaphragm being deflected a selected amount from the neutral position into the first chamber and the pin being removed from the tab assembly.   
   
   
       2 . The indicator of  claim 1  wherein the diaphragm resists movement from the neutral position into the first chamber with a biasing member. 
   
   
       3 . The indicator of  claim 2  wherein the biasing member is a spring. 
   
   
       4 . The indicator of  claim 3  wherein the spring is disposed in the first chamber and against the housing and the diaphragm. 
   
   
       5 . The indicator of  claim 4  wherein the diaphragm includes a deflectable member and a relatively stiff inner member, and wherein the inner member interfaces with the spring. 
   
   
       6 . The indicator of  claim 1  wherein the diaphragm has a width, and the width is greater than a length of the inner cavity measured along the second axis. 
   
   
       7 . The indicator of  claim 6  wherein the diaphragm is circular and the width is a diameter of the circular diaphragm. 
   
   
       8 . The indicator of  claim 1  wherein the tab assembly includes a reset spring, and wherein the tab assembly is biased in the first position with the reset spring and urged toward the second position. 
   
   
       9 . The indicator of  claim 8  wherein the reset spring acts against the housing and flag. 
   
   
       10 . The indicator of  claim 8 , and further comprising a guide plate disposed in the second chamber between the diaphragm and the tab assembly. 
   
   
       11 . The indicator of  claim 10  wherein the reset spring acts against the guide plate and the flag. 
   
   
       12 . The indicator of  claim 10  wherein the guide plate includes a hole adapted to receive the pin. 
   
   
       13 . The indicator of  claim 1  wherein the first axis is generally perpendicular to the second axis. 
   
   
       14 . An indicator suitable for signaling restricted flow of a fluid through a filter mounted in a filter assembly, the indicator comprising:
 a housing having a base and a cover defining an inner cavity;   a deflectable diaphragm disposed within the housing and separating the inner cavity into first and second chambers with a generally fluid-tight seal, wherein the base and diaphragm at least partially define the first chamber, and the cover and diaphragm at least partially define the second chamber;   a calibration spring disposed in the first chamber and acting against the base and diaphragm to resists movement of the diaphragm from a neutral position;   wherein the first chamber is adapted to be in fluid communication with the filter assembly and the diaphragm is deflectable from the neutral position in response to applied pressures within the first and second chambers;   a tab assembly having a hole through the tab assembly, the tab assembly including a flag and a reset spring, wherein the flag is moveable along a first axis from a first position wherein the flag is within the housing and a second position wherein the flag extends from the housing, the tab assembly opposite the diaphragm from the first chamber;   a guide plate disposed in the second chamber between the diaphragm and the tab assembly, the guide plate having a main surface, wherein the main surface is spaced-apart from the cover;   a pin operably coupled to the diaphragm and protruding along a second axis from the diaphragm through the guide plate and into the hole and through the tab assembly when the diaphragm is in at least the neutral position, wherein the second axis is generally perpendicular to the first axis; and   wherein the flag is biased in the first position and movement of the flag from the first position to the second position is actuated in response to the diaphragm being deflected a selected amount from the neutral position into the first chamber and the pin being removed from the tab assembly.   
   
   
       15 . The indicator of  claim 14  wherein the calibration spring is a compression spring. 
   
   
       16 . The indicator of  claim 15  wherein the base includes a foundation and a tap, wherein the tap includes an inlet defining a recess in the tap, and the calibration spring is disposed with the recess. 
   
   
       17 . The indicator of  claim 15  wherein the reset spring is a compression spring. 
   
   
       18 . The indicator of  claim 15  wherein the guide plate includes structures adapted to space-apart the main surface of the guide plate from a base portion of the cover. 
   
   
       19 . An indicator for signaling restricted flow of a fluid through a filter, the indicator comprising:
 a chamber at least partly defined by a diaphragm adapted for movement along a first axis in response to movement of the fluid; and   means, responsive to movement of the diaphragm a predetermined distance along the first axis, for moving a flag along a second axis from a first position to a second position indicative of a restricted flow condition, with the second axis generally orthogonal to the first axis.   
   
   
       20 . The indicator of  claim 19 :
 wherein the diaphragm comprises a stiff inner disk and a compliant outer ring portion, with the outer ring portion including a pin generally parallel to the first axis; and   wherein the means for moving the flag is responsive to movement of the pin a predetermined distance to move the indicator from the first position to the second position.   
   
   
       21 . The indicator of  claim 19 , wherein the indicator includes a cover and wherein the means for moving the flag from the first position to the second position moves a portion of the flag outside and away from the cover. 
   
   
       22 . The indicator of  claim 21 , wherein the cover has an exterior opening, and wherein the means for moving the flag moves a portion of the flag through the opening from the first position to the second position, wherein a portion of the flag is outside the cover in the second position. 
   
   
       23 . A method of signaling restricted flow of a fluid through a filter, the method comprising:
 moving at least a portion of a diaphragm along a first axis in response to movement of the fluid; and   in response to movement of the portion of the diaphragm a predetermined distance along the first axis, moving an indicator flag along a second axis from a first position to a second position, with the second axis generally orthogonal to the first axis and the second position indicative of a restricted flow condition.   
   
   
       24 . The method of  claim 23 , wherein moving the portion of the diaphragm along a first axis in response to movement of the fluid, comprises:
 moving a pin in response to movement of the fluid, wherein the pin is attached to the diaphragm.   
   
   
       25 . The method of  claim 23 , wherein moving the indicator flag along a second axis from the first position to the second position, comprises moving a portion of the flag through a hole from an interior of an indicator to an exterior of the indicator.