—The inlet and outlet pipe should have a 1¹⁄₄-inch connection, this being ample for a coil about four hundred feet in length.
Defrosting.
—To dispose of the accumulation of frost that collects on the coils within the coil bunkers over the beef and hog coolers, it is usual to have a warm brine arrangement consisting of an independent feed header, cross connections to the coils, a tank containing a heating coil and a small pump.
When the frost collects so as to be detrimental, a supply of brine in the small storage tank is heated to about 60° F., and it is continuously pumped through the small auxiliary header, thence into the coil it is desired to remove the frost from, until the frost is loosened, when it is lightly tapped and falls to the floor of the bunker pan. Unless the cellar temperatures are carried low it is unnecessary to use this system in the curing cellars, as the coils will drip from natural melting.
The use of this system of brine installation with a proper defrosting arrangement has much to recommend it as to economy and efficiency, particularly in use with a balanced brine system.
Later Practice.
—A better system superseding that just described is to arrange the coil loft or cooler coils with a brine drip over them to remove the frost, the drip being collected in the pan, conducted to a reservoir and re-circulated. Similar to the manner used with direct expansion piping.
Gardner Curtain System.
—One of the early types of open brine chilling was the Gardner curtain system.
For this system a refrigerator or curtain room is provided, directly above the meat coolers, and of same length and width, in which is fixed an open pan or brine distributing trough, located over the sheets and distributing the brine thereon. [Fig. 28] shows a photograph of the curtains in a refrigerator or bunker room.