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Preheating Stations

3
Dec

Preheating Stations

While not an absolute requirement, most molten metal pump operators benefit from utilizing a preheat station:

  • Less down time between pump changes.
  • Reduced risk of thermal shock damage when installing a pump.
  • Decreased preheat time.
  • Improved safety.

WARNING – GRAPHITE CONTAINING MOISTURE MAY EXPLODE IN MOLTEN METAL!  ALWAYS REFER TO THE MANUAL THAT SHIPPED WITH YOUR MOLTEN METAL PUMP FOR ADDITIONAL SAFETY INFORMATION.

  1. Graphite is a hygroscopic material. Hygroscopic materials attract and retain water molecules including humidity from the air.
  2. Graphite attracts and retains moisture more quickly after it has been in a molten metal bath; while new graphite parts are less susceptible absorbing and retain moisture.
  3. Graphite will also draw moisture from concrete floors. (Never store a pump on a concrete floor.)
  4. Always preheat a pump to remove any accumulated moisture from the graphite.
  5. If any bubbling is observed when introducing a pump into molten metal, immediately lift the pump from the molten metal until the bubbling stops and wait 20 or more minutes before reinitiating the introduction.

Moisture Control

Minimizing graphite moisture content to acceptable levels for immersion in molten metal is no more complicated that slowly preheating the pump for the required period of time. There are two common preheat methods:

  1. Suspend the pump 2 inches or 10 cm over the molten metal for at least 45 minutes (or longer if the pump storage conditions are less than ideal.)
  2. Store the pump in a preheat station.
Preheat Station

Preheat Station

A preheated pump can be introduced into the molten metal 45 minutes sooner than a non-preheated pump. This is a significant downtime reduction. In addition, the operators are placed at less risk during this operation.

High Temperature System, Inc. produces preheat stations for all pumps; including models compatible with pumps made by other manufacturers. Preheat stations are available in both gas and electrically heated configurations. Custom preheat stations are also available upon request.