Sight glass for reaction vessels

Claim 1

A SIGHT GLASS FOR COOPERATION WITH AN OPENING IN A REACTION VESSEL, SAID SIGHT GLASS COMPRISING A LENS HOLDING SLEEVE HAVING AN OUTWARDLY PROJECTING CONTINUOUS FLANGE AT ONE END THEREOF ADAPTED TO ENGAGE THE WALL OF THE VESSEL SURROUNDING SAID OPENING, SAID SLEEVE ALSO HAVING AT SAID ONE END AN INWARDLY PROJECTING LIP, A LENS RECEIVED WITHIN SAID SLEEVE AND SUBSTANTIALLY FILLING THE SAME, THE THERMAL COEFFICIENT OF EXPANSION OF SAID LENS BEING DIFFERENT FROM THE THERMAL COEFFICIENT OF EXPANSION OF SAID LENS-HOLDING SLEEVE, SAID LENS BEING HELD IN PLACE WITH A FLUID PACKING HAVING A COEFFICIENT OF EXPANSION COMPATIBLE WITH THE DIFFERENTIAL IN THERMAL COEFFICIENT OF EXPANSION BETWEEN SAID LENS AND SAID SLEEVE, SO THAT CHANGES IN TEMPERATURE DO NOT ADVERSELY AFFECT THE SEAL BETWEEN SAID PACKING AND SAID LENS IN SAID SLEEVE, A RESILIENT GASKET INTERPOSED BETWEEN AND SEALING THE SPACE BETWEEN THE LENS AND THE LIP, AND A MOUNTING SUPPORT RECEIVING THE LENS HOLDING SLEEVE AND SEATED ON THE FLANGE THEREOF TO LIMIT THE PRESSURE APPLIED BY THE SUPPORT TO THE GASKET AND THE LENS, SAID SUPPORT ALSO BEING ADAPTED TO SECURE THE FLANGE OF THE LENS HOLDING SLEEVE IN FIXED ENGAGEMENT WITH THE WALL OF SAID VESSEL AND IN ALIGNMENT WITH SAID OPENING.