Bimetal indicator device with a heater energized under all operative conditions

Claim 1

A INDICATING DEVICE FOR A FLUID SYSTEM, SAID DEVICE COMPRISING: A SUPPORT ELEMENT HAVING A HOLLOW INTERIOR AND A THREADED PORTION ADAPTED TO BE THREADED INTO THE WALL OF A FLUID CARRYING SYSTEM SO THAT A PORTION OF SAID SUPPORT ELEMENT IS DISPOSED IN FLUID THEREIN; A FIRST TERMINAL INSULATEDLY CARRIED BY SAID SUPPORT ELEMENT AND INCLUDING A CONDUCTIVE PATH TO THE HOLLOW INTERIOR OF SAID SUPPORT ELEMENT, SAID FIRST TERMINAL CONDUCTIVELY ENGAGING AN INDICATTRICAL POWER SOURCE; A SECOND TERMINAL ENGAGING AN INDICATING MEANS AND BEING INSULATEDLY CARRIED BY SAID SUPPORT ELEMENT, SAID SECOND TERMINAL INCLUDING A FIXED CONTACT MEANS EXTENDING INTO THE HOLLOW INTERIOR OF SAID SUPPORT ELEMENT; THERMAL RESPONSIVE CONTACT MEANS CARRIED BY SAID SUPPORT ELEMENT AND CONDUCTIVELY ENGAGING SAID FIRST TERMINAL, SAID CONTACT MEANS BEING CARRIED IN JUXTAPOSITION TO THE FIXED CONTACT MEANS OF SAID SECOND TERMINAL AND BEING DEFLECTABLE INTO ENGAGEMENT THEREWITH IN RESPONSE TO A DISRUPTION OF A TEMPERATURE EQUILIBRIUM BETWEEN THE CONTACT MEANS AND THE FLUID SURROUNDING SAID SUPPORT ELEMENT; AND HEATER MEANS THERMALLY AND ELECTRICALLY CONDUCTIVELY ENGAGING SAID CONTACT MEANS TO FORM A FIRST CIRCUIT FOR RAISING THE TEMPERATURE OF SAID CONTACT MEANS TO A POINT WHICH IS NORMALLY OFFSET BY THE TEMPERATURE OF THE FLUID THEREBY MAINTAINING THE DEFLECTABLE CONTACT MEANS AWAY FROM THE FIXED CONTACT MEANS, SAID CONTACT MEANS BEING DEFLECTABLE INTO CONDUCTIVE ENGAGEMENT WITH THE FIXED CONTACT MEANS TO COMPLETE A SECOND ELECTRICAL CIRCUIT TO THE INDICATING MEANS WHILE MAINTAINING THE FIRST CIRCUIT ENERGIZED WHEN THE FLUID DISPOSED AROUND THE SUPPORT ELEMENT IS AT A TEMPERATURE WHEREIN THE TEMPERATURE EQUILIBRIUM BETWEEN THE CONTACT MEANS AND THE FLUID IS NOT MAINTAINED WITHIN PREDETERMINED LIMITS, SAID SUPPORT ELEMENT INCLUDING A SUBSTANTIALLY CYLINDRICAL SHIELD SURROUNDING THE PORTION THEREOF DISPOSED IN THE FLUID CARRYING SYSTEM A SPACED DISTANCE FROM SAID SUPPORT ELEMENT THEREBY PREVENTING THE FLOW FORCE OF THE FLUID IN THE FLUID CARRYING SYSTEM FROM ACTING ON SAID PORTION OF THE SUPPORT ELEMENT.