Electronic temperature control for pumps

Paul Boughton
Because of the temperature/viscosity relationship of many products, such as bitumen, plants and pumps have to be heated. Thermal oil or water/steam systems are widely used but need complex infrastructure. Electric heating is making pump temperature control much easier especially in mobile plants, where other possibilities for heating are not available.
The Rotan pump can be equipped with a heating element from 330W within the pump idler, this being ideally placed in the very centre of the pump. In many applications this simple and reliable solution is sufficient but for higher demands, additional electric heating elements can be placed in the rear cover.
A thermostatically controlled operating system is available, preventing the pump from being started before the correct operating temperature is reached and with the additional benefit of preventing the pump from overheating on temperature critical applications.
Two 8-in ROTAN pumps for Asphalt transfer installed in 2004 at one of the major Asphalt terminals for road construction in Sweden. Both were equipped with electrical heating and temperature control via one PT-100 mounted on the pump casing. At 120°C the temperature gives the signal to start the pump avoiding that it starts under cold conditions. At 170°C the electrical heating is shut off via the temperature control preventing the pump from being over-heated.
Since the start up in 2004 the pumps have been running without any interruption and maintenance, saving a lot in energy cost for the user.
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Desmi Rotan is based in Nørresundby, Denmark. www.desmi.com