General Motors of Canada

HH Angus designed the Welder Water System for the car assembly and GMT 800 C/K Truck plants in Oshawa. These systems provide cooling water for all the robot welders, circulating cooling water to the tips of the welders to prevent overheating.

 C/K Truck Plant 

This plant’s welder water system consisted of a cooling tower system and cooling distribution system. The pumps re-circulate tower water from the indoor sump through heat exchangers and up to the cooling towers. The cooling tower system featured five main components: Cooling towers, indoor sump, recirculation pumps, plate heat exchangers and centrifugal filter units.

The two vital conditions that had to be maintained were temperature and differential pressure. A temperature sensor on the hot side of the heat exchanger (closed loop side) controlled the staging of the cooling towers and the speed of the variable speed drive cooling tower fans. Pressure differential transducers located at the index runs staged the cooling water pumps to maintain differential pressure. The welder tips are extremely sensitive to differential pressure, so very tight pressure tolerances have to be maintained at all times.

Car Assembly Plant

In the Car Plant, renovations required the relocation of the welder water system, together with the supply and installation of three new cooling tower pumps and three new circulation pumps.

The three cooling tower pumps were each 100 horsepower, electrically driven, and with a flow rate of 2670 US gallons per minute. The three circulating pumps were each 150 horsepower.

The distribution piping system extended over 3,000 feet, serving welding robots throughout the car assembly plant. The heat transfer, between the circulating (robot cooling) water and the tower cooling water, takes place in four plate-type heat exchangers.