Milk Pumping – Variable Speed Drives (VSD) can also be used on milk pumps to control the flow of milk through a precooler or heat exchanger to increase their cooling efficiency. A constant speed milk pump can pump milk at a rate of 30 gallons per minute (gpm) or more. In order to get maximum cooling of the milk, the water to milk flow rate needs to be 1:1 so a minimum of 30 gpm of water would be needed. However, many precoolers require a water:milk ratio of 2:1 so 60 gpm of water would be needed. Many older farms do not have this kind of water system capacity, therefore one option is to install a VSD controller on the milk pump to lower the average milk flow through the precooler. This reduces the water demand (gpm) need to achieve maximum efficiency from the precooler.
Refer to UW Extension bulletin A3784-07: “Energy Conservation in Agriculture: Variable Speed Milk Pumps“.
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