Safe, Economical Way to Achieve High Quality Asphalt Paint Coating

Circulation Heater

The Challenge
Controlling the viscosity of asphalt paint is paramount to the quality of the end product.  This must be achieved by constantly maintaining a 90° F (± 5°) temperature in a 3000 gallon tank in which the bar joists are dipped. Because the paint is thinned with mineral spirits, any heat source within 30 or 40 feet must be explosion resistant. The operation is performed in an unheated corrugated steel building.

The Solution
Chromalox recommended a heat transfer system which utilized jacketed pipelines for in-going and returning paint. Pipelines contain 66 gallons of water and Prestone mix. Two Chromalox Electric Circulation Heaters - 30 and 40 kW on 480 volts - are the heat source. An indicating temperature controller with bulb at the inlet of the return jacket set at 90° F controls input to heaters whose built-in thermostats are set at 210° F.


  • With electric heaters and control, temperature and viscosity are constant, therefore, the coating quality is consistent regardless of building temperature.
  • In contrast with alternative heating methods, the consistent temperature of electric heat results in a savings of thinner, which contributes to coating economies.
  • All guesswork has been removed from the operation.
  • The heating method is safe and has been approved by Factory Mutual Insurance Company.
  • The system, in operation 16 hours a day for almost two years, has been completely dependable. No maintenance has been needed.
  • No manpower is required for the operation of the automatic heating system, adding further economy.