HOMOGENIZING MACHINE (PHOTOGRAPH NUMBER 8)
Scope and Content Note: Consumer demand initiated production of homogenized milk although homogenizing process used previously to produce canned milk and ice cream mixes. Technical problems in building machine to allow dismantling for proper cleaning and operating under 3,000 pounds of pressure later solved when machine built with cylinder block of solid piece of stainless steel. Homogenizer raised pressure of milk to 3,000 pounds per inch to break up fat globules into uniform size and equal buoyancy. Globules given a negative electrical charge to prevent them from floating to surface and forming a layer of cream on top of milk. Blochowiak points out clarifier, a circular machine containing a series of plates and thin film through which milk passed to remove, by centrifugal force, unwanted foreign particles from milk, including leukocytes. Early clarifiers, replacing inefficient, manual straining technique, processed milk at 130 degrees F.; “cold clarification” process later development. Flash pasteurizing machine, composed of over 150 consecutively arranged stainless steel plates; on one side, pasteurized milk; on the other, incoming raw milk. No danger of mixing the two since pasteurized milk under 15 pounds pressure, raw milk in a vacuum. Plates also served as cooling device. Flash pasteurizer, control panel, homogenizer and clarifier replaced seven alternately operating holding tanks which retained milk for one-half hour. Decision to modernize equipment based on efficiency and energy-saving factor. Machines generated much heat, steam, and fairly loud hum, although noise not unbearable.