THE GREAT MULLARD MAGIC BLOG — ANNEALING FURNACE

Here we see a wonderful evocative photograph of operator Dabney Grimble attending to CRT bulbs at Mullard Mitcham. Pictured is the manufacturing stage where the neck tube has just been welded to the bulb.  To avoid heat induced stress at the weld junction, the bulbs are placed in an annealing furnace for 150 minutes along a graduated tunnel furnace which controlls the rate of glass cooling.   The bulbs travel by carrel to the annealing furnace whilst suspended in a vacuum chuck which is kept at the same temperature as the bulb to prevent breakage.    Placement of the vacuum...