Filter condition indicator device

Claim 1

AN INDICATOR DEVICE ASSOCIATED WITH A VALVE COMPRISING A HOUSING HAVING A PASSAGEWAY THEREIN, SAID PASSAGEWAY HAVING SIDE WALLS, A TUBULAR INSERT SECURED TO SAID PASSAGEWAY SIDE WALLS, SAID INSERT HAVING RADIAL APERTURES ADJACENT ONE END, A CYLINDRICAL VALVE MEMBER POSITIONED IN SAID TUBULAR INSERT, RESILIENT MEANS ARRANGED TO URGE SAID CYLINDRICAL VALVE MEMBER INTO OVERLYING RELATION WITH SAID RADIAL APERTURES TO THEREBY CLOSE SAID PASSAGEWAY, INDICATOR MEANS CONNECTED TO SAID VALVE MEMBER AND ARRANGED TO INDICATE THE RELATIVE POSITION OF SAID VALVE MEMBER IN SAID INSERT, SAID VALVE MEMBER BEING RESPONSIVE TO THE PRESSURE OF FLUID IN SAID PASSAGEWAY AND OPERABLE AT FIRST PREDETERMINED FLUID PRESSURE IN SAID PASSAGEWAY TO MOVE SAID VALVE MEMBER IN SAID PASSAGEWAY A PREDETERMINED DISTANCE, SAID INDICATOR DEVICE CONNECTED TO SAID VALVE MEMBER INDICATING THE RELATIVE MOVEMENT OF SAID VALVE MEMBER IN SAID INSERT, SAID VALVE MEMBER ARRANGED TO MOVE SAID PREDETERMINED DISTANCE AND MAINTAIN A PORTION THEREOF IN OVERLYING RELATION WITH SAID INSERT APERTURES TO MAINTAIN SAID PASSAGEWAY CLOSED TO THE FLOW OF FLUID THERETHROUGH, SAID VALVE MEMBER BEING FURTHER RESPONSIVE ABOVE ANOTHER PREDETERMINED PRESSURE TO MOVE TO ANOTHER POSITION IN SAID INSERT SO THAT SAID VALVE MEMBER IS SPACED FROM SAID INSERT APERTURES TO OPEN SAID PASSAGEWAY FOR THE FLOW OF FLUID THERETHROUGH, SAID INDICATOR DEVICE ARRANGED TO INDICATE THAT SAID PASSAGEWAY IS OPEN FOR THE FLOW OF FLUID THERETHROUGH.