ICE-MAKING. One of the most important appli cations of refrigeration is the manufacture of artificial ice. There are several methods of ice manufacture practiced oonnurcially, and each of these will be briefly described. and, afterward,, a more detailed description will be presented of one of the most popular atom iota compression can systems employed in America. The great (litli culty in manufacturing artificial ice• is. that producing a clear. tran,parcnt it aterial, for. un less special provisions are made to get rid of it, the air in the water fails to escape•, because of the rapid freezing. and an opaque ice containing .air bubbles and of inferior keeping qualities is pro duced. Five methods may la. employed fur pre venting this opacity and clear crystal ice: (1) Freezing the water slowly at compara tively high temperatures; (2) agitating the water in cans, molds, or cases during the proves: of freezing .o as to admit of the escape of the im prisoned air; (3) forming thin slab. of ice on what is known as the wall or plate system: (4) freezing the water in shallow stationary cells; and 1.5) de-aerating the water before placing it in the mold. or cells. Freezing the water slowly at comparatively high temperatures i, simply an imitation of the natural process. the water being exposed in well-insulated room, to an atmosphere cooled below freezing point. The proees is too slow to be successful commercially.
In the can system, which is one of the most popular, metal can- are set in a tank containing chilled brine and these cans are filled with the water to be frozen. Extending down into these can: is a bar or rod of wood which is given a swinging motion by suitable mechanism, boiling, or frozen in a vaeumn, or distilled. The vacuum system is but little used. In the other system, the evaporated or distilled water is frozen either by the can system or plate system.
Turning now to a speeitic example of lee-mak ing, Fig. 6 .how• a plant for making ice on the ammonia compressor can system: The ammonia compressor plant has already been dese•ribed in a preceding section and will Le negleeted here. To follow now the water from the well to the 11)a ling platform. where it is delivered a- ice•, We begin with the Weil-Water pump in the boiler house. Water from this pump splits into two current-. one of which rises to the top of the building, and discharges into the water-storage tank. This water, a- shown by the pipes leading from the tank, ttows over the gas and nil cooler and also over the ammonia condenser. From the pans, or cemented door, on w hick these stand it th.ws thus agitating the water. and facilitating the escape of the contained air. In the plate or wall system the water to be frozen is placed in a large refrigerator tank which is divided into compartments by a series of parallel hol low partitions. In these hollow partition: brine is circulated, causing a sheet or plate of ice to freeze to both sides of each. When these ice plates have frozen to a thickness of S to 12 inches, the cold brine is drained from the partitions and replaced by warm brine, which causes the plates to melt loose, after which they are lifted front the" tanks and sawed into blocks. The standard size of plate in the United States is 8 X 16 feet X 11 inches. As in the can system, agitators are em ployed to expel the air from the water during freezing. In the stationary cell system a tank, as in the plate system, is divided by both transverse and longitudinal hollow partitions, so that the iee is frozen in rectanoular blocks instead of in long flat plates. The of freezing and freeing the ice and of agitating the water are the same as in the plate system. In the de-aerating system
the water to be frozen is either evaporated by to the floor below, where it 101ter, the steam con denser. After traversing the condenser it passe•' through the next (lbw, runs ailing the ceiling. and empties into the vertical standpipe (seen to the extreme left) connecting with the sewer. Water from the water storage also flows by a pipe (hi 1 den by the ammonia I.onderNer) to the condensed water cooler. from the base of which it passes through the floor, runs along the ceiling of the first floor. and empties into the sewer standpipe. This dispose•> of one current from the well-water pump: the other passe, through the sand filter. whence it rises to the third Mew and passes through the• heater. From this heater it again de.ee•mds to the water collector in the hotter house, %%Ileum it is drawn off tl e boiler•feed pump, and by it for boiler, it the boilers in the fmmt of live The pipe eonveying this lice lots branches supplying the eterine, the well-water pump, the boiler-feed pomp. and is ilhifig of the first floor. to the third door. Where it connected with the reboiler and :11-0 the :team filter. The purpose of its connection with the reboiler is apparent; the connection with the steam filter is utilized to automatically supply a small quantity of live steam to make up for any deficiency in exhaust steam. Other connections of the live-steam pipe to the various apparatus are shown. which are used for cleaning out. The exhaust steam from the engine, and also for the two water pumps, passes beneath the first floor and rises through the boiler-room and outside the main building to the third floor. Before it enters this it has a chance to escape through the pressure release valve if for any reason the vari ous apparatus through which it passes should cause sufficient. back pressure to impair the proper working of the engine. The exhaust steam passes first into the steam filter, thence into the heater, where it heats the water which as we have already seen passes through this same heater on its way to the boiler. From the heater it passes to the condenser, thence to the reboiler. From this it goes through the condensed-water cooler to the deodorizer on its way to the cold-storage tank. From the cold-storage tank water is fed by a hose in any can whose place may be rendered va cant IT the withdrawal of a can of ice. There we must leave the now thoroughly purified and distilled water in repose for some sixty hours. After this interval of time the can is lifted by the ice crane suspended from the carriage on which it is run down the tank-room to the sprinkler. In the sprinkler the can receives a shower bath of warm water and the ice when loosened drops out of itself and glides into the ice-storage room, the sprinkler in the meantime automatically put ting itself into position to receive another can, thereby shutting off the supply of warm water. The cake of transparent ice is allowed to remain in the ice-storage room until the time for the wagons to appear at the loading-platform ap proaches, when it and as many of its fellow blocks as are required are withdrawn into the ante room. A block of ice may pass straight through the ice-storage room and the anteroom to the loading platform. or it may remain a week or two in the storage. This ice-storage room is seen to be supplied with refrigerating pipes, so that if the demand is fluctuating the blocks will be pre served intact, only so much being withdrawn into the anteroom as is necessary for immediate use. The following table shows the structural sizes and weights of blocks made by the can system: