The operation of this apparatus is as follows: Sufficient ammonia-water, 20° Beaume, is pumped into the machine to fill the coil in the cooler, the exchanger, and the coil in it—the absorber until it shows in the gauge-glass, and the ammonia-boiler until it is ap to the lower gauge-cock. Steam is admitted from the steam-boiler to the coils in the ammonia-boiler. This causes the gaseous ammonia to leave the water and ascend through the rectifier in the top of the boiler, and pass into the coils of the condenser ; and under through combined pressure and temperature of the water surrounding the coils the gaseous ammonia turns into a liquid and runs down into the collector, the amount of liquefied gas being shown by the glass gauge on its side. The liquefied gas then passes through the coil in the gas-exchanger and out through pipes to the regulating-valve. Between this valve and the ammonia-boiler a continual press ure is kept up (depending on the temperature of the condensing water used in the liquefier). As the liquefied gas passes through the valve into the pipe-manifold, in which a very low pressure exists, and consequently it expands and turns into gas again, producing a low temperature, varying from 4° below to 10° above zero, and as it circulates through the coils in the bath of salt water it absorbs the heat of the water in the cans through the medium of the salt water, and results in its being frozen. The gas passes out through the bottom of the coils into the manifold, and then into the gas-exchanger, and then comes in contact with the coil containing the liquefied gas on its way to the bath, and reduces its temperature. The ex panded gas continues on out at the top of the exchanger, and passes on to the distilled-water tank, through a coil in the bottom, and cools the water used for filling the cans, the contents of which are to be frozen. The gas then continues on to the absorber, and passes down to the bottom, where it is reabsorbed by the poor liquor, or the same water from which it was driven out in the ammonia-boiler.
In order to cool the poor liquor so that it will reab sorb the expanded gas, it is drawn out from the bottom of the ammonia-boiler through the coil in the poor liquor exchanger. thence through the coil in cooler, where it is made of the same temperature as the river or well water, and thence into the absorber. Here the gaseous ammo nia is readily absorbed by the poor liquor, which generates heat. The heat is carried off by water passing through the coils already mentioned. The now rich liquor passes into the pump, and is forced through the poor-liquor ex changer and then carried into the top of the ammonia boiler, thence into the rectifier, where it meets the rich gas coming up, which its partially charged wih watery vapor, and partially freed from it by its contact with the rich liquor which passes down into bottom of the ammo nia-boiler, and is now ready to go through the same pro cess over and over again.
At the beginning of the operation, the steam that was admitted from the steam-boiler into the coils passes out in the ammonia-boiler to the heater partially condensed, but it does not furnish enough distilled water for the amount of ice the machine will make. The coil through which the
feed-water passes to the steam-boiler is inclosed in the heater, and in passing through it condenses enough steam to supply the machine. The condensed steam is then con ducted to the distilled-water tank and freed from the in condensible gases and cooled, and then drawn out to fill the ice-cans as occasion may require. The operation is continuous, one part not being delayed by another, but all moving together and at the same time.
The operation of refrigeration is performed in the same manner, with the exception that the heater, distilled-water tank, and the cans in which the ice is made, are dispensed with ; the salt water in the bath is cirenlated through pipes in the apartments to be cooled, or, if preferable, the coils and salt water in the bath can lie dispensed with, and the gaseous ammonia allowed to circulate through pipes in the apartments. A complete plant for the manufacture of ice consists of the parts enumerated above, with the addition of steam-boiler, water-pump, boiler-feeder, ice-trnek, and dump.
Tests of Absorption-Xachines.— Nr. Frederick Colyer, Proc. Inst. of Mech. Eng., May, 1886, page 248, gives the results of a test of a Pontifex-Reece Iumnonia absorption-machine cooling 6,388 gals. (imperial gal. = 10 lbs.) of water per hour through 10° F. The condensing water used per hour was 1.320 gals. at 454' F. The fuel-consumption was 100 lbs. of very common coal per hour. The steam-pressure was 50 lbs. per sq. in. The same machine, when employed for making ice, is capable of making 15 bons in 2-1 hours, if worked with three boxes, In the test, two boxes were used, making 10 tons. The coal-consumption was 120 lbs. per hour. or 102 lbs. of coal per ton (2,240 lbs.) of ice-11.7 lbs. ice per lb. coal.
the latest type of ice-making machine built by the Consoli dated Ice-nichine Co. the compressors are set vertically, and are single-acting, compressing only on the up-stroke. A cross-section of the ammonia-cylinder is given in Fig. 1. The gas has free entrance to and exit from the cylinder below the piston. thus keeping the pump cylinder and piston cool. The extreme lower portion of the pump forms an oil-chamber or reservoir, which effectually seals the stuffing-box. The auction and discharge valves are located in the pump-head. There are two cushioned discharge-valves, set in steel cages, which are held in position in the pump-heads by means of yokes and set-screws.
The suction and discharge pipe connections are made outside of the pump-head. All the gas is expelled at each stroke.
Tests of Compress2Ion-Machines.—An important test of a 75-ton compression-machine of the above-described type has been made by Prof. J. E. Denton, and is published in Trans. A. S. M. E., November, 1890. The principal results are given in the following table : The above figures are equivalent to assuming a bailer efficiency of 8'3 lbs. of water evaporated per lb. of coal under working conditions.