The company has 2,500 employees across Canada, including 800 at its Toronto facility, where production runs 24 hours a day, seven days a week. Chocolate bars are tempered (gradually heated and cooled) in a process similar to that used in steel production.

Because the Toronto facility has so many production lines and different chocolates, company staff members are constantly adjusting temperature controls. Much of their work is done during a changeover on a production line. But the manual adjustments and icing problems on the evaporator coils meant that a conversion process could take up to 24 hours.

To find a better way, Cadbury turned to CIMCO Refrigeration, whose employees in turn met with officials of Hansen Technologies of Burr Ridge, IL. It was proposed that four sealed motor valves be installed to control temperature on a Carle 600 production line. The valves were added to the suction line of each of the four cooling coils.

Cadbury officials said icing problems have now been eliminated and the time required to change over the line has been reduced to a few hours. Temperature setting is now completed with the touch of a button.

The sealed motor valves control temperature at each stage of the tempering process ±0.5 degrees C of the setpoints. A 4-20-mA signal tied directly into the plant computer monitors coil outlet temperature. The signal is sent to the microprocessor, then to the motor of the valve, which opens or closes automatically based on temperature setpoints in the production line.

Dave Giza of Hansen Technologies said that no pressure drop is required to operate the valve. It can be used with refrigeration systems using R-22, ammonia, R-134a, glycol, and brines.

For more information, contact Hansen Technologies at 630-325-1565; www.hantech.com (website).

— Peter Powell

Publication date: 09/02/2002