Batch drying in a circulating hot air oven was slow and involved additional handling in loading and unloading. Equipment and personnel for subsequent operations were capable of handling more work than the oven could produce.
Since a continuous radiant oven seemed much simpler, the customer designed and constructed in its own shop, the conveyorized tunnel oven. A total of 16.4 kw of electric heat is used.
Heat source throughout was the Chromalox Type U-RAD Electric Radiant Heater. Sixteen heaters were used in the three heat zones as follows (each zone was controlled by a Chromalox Input Controller):
Zone 1- two U-RAD-22, 1600 watts each, on each side.
Zone 2 - four U-RAD-43, 2900 watts each, on each side.
Zone 3 - two U-RAD-2, 800 watts each, on each side.
All heaters were mounted diagonally to permit even heat distribution on the sides of the tubes.
- It penetrates the glass to quickly dry the line on the inside of the tube.
- Quality control is much easier to maintain.
- Elimination of batch handling lowered the cost per unit.
- Heat is easily adjustable and economical as no more heat is used than is needed.
- There's no guesswork - Chromalox Input Controllers always produce the same radiation output at any given setting.