THE GREAT MULLARD MAGIC BLOG — VALVE SEALING

In this process, where sealed valves were passed from the last station of the sealing machine, a mechanical tri-claw hand fitted with an asbestos glove (imagine the 'elf n safety implications today!!!) transfered the valve to the first vacant position on the pumping machine. The pumping machine comprised of another rotating table which had a sequence of rubber bungs around the periphery.  Each bung was connected to a vaccuum manifold supplying a high torr vaccuum.  As the valve abutted a bung, the process of pumping commenced.  As the valve rotated around the table, the valve passed through a heated convection...

Today, we shall look at valve sealing.  First off, the cage-base assembly was inserted into the bottom end of the envelope and then mounted vertically onto a rotating table on the sealing machine.  At the first station on the table, the location of the electrode assembly with respect to the bottom of the valve was automatically adjusted. The aligned assembly then passed through a four stage sealing process where gas blow pipes played upon the the walls of the envelope at a point exactly opposite the rim of the glass base.  Gradually, the glass softened and hence the envelope and...