In dry grinding operations, the only cooling comes from the air passing over the work as it is being ground. By careful use of the airflow through the grinding zone, production rates may be increased, quality improved and abrasive life increased.
Some of the heat generated will leave in the ground part, almost all of the remainder will leave in the exhaust air. As little heat as possible should be left in the part. We should, therefore, try to remove all of the heat with the air.
The volume of exhaust air required can be estimated as follows:
1 Horsepower will add 42.5 BTU/minute to the system.
1 Cubic foot of air will pick up 1/2 BTU if it increases in temperature 30š F.
This would indicate that the exhaust system should pull 2 x 42.5 Ft3 or 85 Ft3 of air per minute through the grinding zone for each horsepower used by the grinder.
Two 20 HP motors operating at 80% of capacity would require:
2 x 20 HP x .80 x 85 Ft3/Min/HP or 2720 Ft3/Min of exhaust air
Guards, hoods and covers should fit tightly so that entering air is directed to the area where it will do the most good. Cooled outside air led to the grinder can further aid in the dissipation of heat as well as conserving energy used in space heating.
Exhaust fans, fan blades and ductwork must be kept at top efficiency and air filters kept clean.