In a wet grinding operation the heat energy that develops at the grinding face must be removed by the coolant. This heat is contained within the coolant system and removed through evaporation or refrigeration. The following relationships may help in understanding and arriving at adequate coolant requirements:

(A) 1 HP will add 42.5 BTU per minute or 2550 BTU per hour to the system. If all of the heat is contained within the system and the coolant is allowed to rise 15š F, then:

2550 BTU/HT/HP ____________________ 15 BTU/Lb. x 8.3 Lb./Gal.

or about 20 Gal. of coolant capacity is required for each HP used per hour of operation.

 

(B) With the coolant at 90š F, then 1040 BTU are released from the system for each Lb. of water that is evaporated.

 

2550 BTU/HT/HP ______________________ 1040 BTU/Lb. x 8.3 Lb./Gal.

about .30 Gal. or 2.5 pints of water should evaporate from the system every hour for each HP used.

The coolant volume should be large enough to store a fair amount of heat while evaporation is encouraged through sprays, cascades, or large exposed water areas with a good flow of air across the surface to promote evaporation.

If the coolant temperature still climbs to an unacceptable level, refrigeration should be added to the system.

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