Patent ID: 7401546

Claim:
A batch pasteurizer for liquid dairy products, comprising: a first cylindrical container for containing the liquid to be heated and cooled; a second cylindrical container surrounding the circumference and height of said first container to form an annular chamber therebetween, with the bottom of said second container displaced vertically below the bottom of said first container to permit fluid circulation therebetween, so that the bottom of said first container and substantially the entire wall portion of said first container serve as heat transfer surfaces; means for filling said annular chamber with heating or cooling fluid; means for draining said fluid from said annular chamber; at least one electrical heating element between the bottoms of said first and said second container to heat the heating liquid between said bottoms; circulation means comprising an impeller with drive means mounted atop a lid fitted to said first container, and positioned to agitate the treated fluid when rotated by said driving means; a helical coil of thermally-conductive tubing extending from the top of said second container to the bottom thereof and connected to a source of cooling fluid so as to circulate same and cool the heating fluid in said annular chamber thereby; temperature sensing means for measuring the temperature of the liquid product during the heating and cooling processes; temperature sensing means for measuring the temperature of the heating and cooling fluids within said annular chamber; switching and valve means for controlling the flow of heating fluids to and from said annular chamber and to said helical coil; and control means for executing a cycle of introducing and heating said heating fluid within said annular chamber and said space between said container bottoms for a time effective to bring the liquid product to a pasteurization temperature and hold it at said temperature for a time effective to complete pasteurization, thereafter directing a cooling fluid through said helical coil and shutting off said heating means for said heating fluid for a period of time effective to cool said liquid product to a temperature suitable for storage or immediate use.