In plastic extruding, operating efficiency is key. This can be a challenging task because the equipment needs to operate at high temperatures, and it is expensive for companies to shut down for repairs.
As one of Europe’s leading suppliers of extruded plastic sheets, Arla Plast AB produces 12,000 tonnes a year of high quality transparent polycarbonate sheets used for machine protection, safety glazing and hockey rinks. The Swedish company operates 10 extruder lines that produce plastic sheets over the course of five shifts a day. In the extruder line, a calender with three rollers presses the plastic into sheets. A pump station with three pumps supplies the calendar with heat transfer fluid, which heats up the rollers to their operating temperature range of 302 to 356 oF (150 to 180oC).
An ongoing problem the company faced was quick degradation of the heat transfer fluid, according to Gerry Christensen, the Arla Plast technical chief responsible for maintaining all the lines and equipment in the factory. “The oil degraded very quickly and got very black,” he said. “That hurt the pumps, and inside the rollers we had a lot of black sludge from the oil, which led to many problems.”
When the oil broke down, it created a chain reaction of consequences. “After six months, we had to put new bearings in the pumps,” says Christensen. “We had to repair them, and it costs a lot of money to stop a line like this. We had one or two days to repair the pumps, then we could run for six months again.”
Over the years, Arla Plast experimented with various heat transfer fluids to find a solution. Christensen found his with Petro-Canada’s Calflo HTF heat transfer fluid.
Arla Plast’s local distributor, Canadian Oil, helped Arla Plast change over the system. The company recommended flushing the system with Petro-Canada’s cleaning fluid, which was heated and circulated through the system to clean it internally. It was then flushed and filled with Calflo HTF.
“After we changed to Petro-Canada’s heat transfer fluid, we have been running for three years without problems,” states Christensen. “It solved a lot of problems, not just the short oil life. The pumps are working, and we haven’t repaired any pumps since three years ago.”