Shaft seal employing seal gas with means for indicating proper flow thereof

Claim 1

IN COMBINATION WITH A SHAFT, A WALL HAVING AN OPENING THEREIN THROUGH WHICH SAID SHAFT EXTENDS, AND A SEAL ARRANGEMENT FOR PREVENTING LEAKAGE OF A RETAINED GAS FROM ONE SIDE OF SAID WALL TO THE OTHER THROUGH A CLEARANCE BETWEEN SAID SHAFT AND SAID WALL, COMPRISING MEANS FOR INTRODUCING INTO THE CLEARANCE BETWEEN THE ENDS OF THE OPENING A SEAL GAS AT A TEMPERATURE DIFFERENT FROM THAT OF THE RETAINED GAS TO SEAL THE CLEARANCE AGAINST LEAKAGE OF THE RETAINED GAS THERETHROUGH, THE IMPROVEMENT WHICH COMPRISES A TEMPERATURE SENSING BETWEEN THE MEANS RESPONSIVE TO A PRESSURE DIFFERENT BETWEEN THE RETAINED GAS AND THE SEAL GAS AT THE POINT OF ITS ENTRY INTO SAID CLEARANCE TO SUBJECT THE SENSING DEVICE TO THE EFFECT OF THE TEMPERATURE OF EITHER ONE OF SAID GASES HAVING THE GREATER PRESSURE, WHEREBY INADEQUACY OF THE PRESSURE WILL THE SEAL GAS TO PREVENT LEAKAGE OF THE RETAINED GAS WILL BE SHOWN BY A TEMPERATURE INDICATION CLOSER TO THE TEMPERATURE OF THE RETAINED GAS AND SUCH PREDOMINANCE OF THE PRESSURE OF THE SEAL GAS AS WOULD CAUSE FLOW THEREOF TOWARD THE RETAINED GAS WILL BE SHOWN BY A TEMPERATURE INDICATION CLOSER TO THE TEMPERATURE OF THE SEAL GAS.