Service Bulletin: SB 093.1
Subject: Tubular Heater Thermal Cement
The use of thermal cement to improve the operating life of tubular heaters as outlined in Service Bulletin 56-11-78 has been found to be beneficial.
However, it has come to our attention that the described curing procedure is not always followed, but rather the heater holder assembly is installed directly on the station and heated to operating temperature. This is detrimental to heater life and defeats the purpose of the thermal cement.
The described procedure is repeated below and requires a spare Heater Holder Ring Assembly. This allows for a ready replacement when needed. The tooling heated ring can be transferred at installation or a spare pre inserted in the Holder Ring.
Using temperature control unit and regulated 120 volt power source set the controller for 100&Mac251; F (40&Mac251; C) for one hour. Then raise temperature to 130&Mac251; F (55&Mac251; C).for thirty minutes and raise temperature to 160&Mac251; F (70&Mac251; C) for twelve hours. The cement is then cured and the assembly can be installed at any time in the station assembly. When replacement is necessary, use the front tapped holes in the Holder Ring as jack screws to push the heater and cement out. Any remaining cement may be easily removed after soaking in water.
With tubular heaters installed by this method and the heater leads supported as described in Service Bulletin 54-10-78 and 56-11-78, heater life will be greatly extended.
One (1) First Bottom-Heat Ring Holder Assembly less tooling ring
One (1) tooling Heated Ring