Norwich bulletin., 1914-03-14
INSTRUCTED ENGINEERS
 ON REFRIGERATING PLANTS.
Talk Given by Harry Leonard, With
 Lantern Slides to Illustrate.

 Before a good sized number of sta tionary engineers and some of their | friends, Harry Leonard gave an illus i trated talk on Refrigerating Plants | Friday evening in the associations | room in the Bill block, on Shetucket i street at the meeting of Norwich As sociation of Stationary Engineers, No. 1 6. Mir. Leonard's talk proved very in 1 teresting and instructive and he held 1 the close attention of all present throughout The slides, of which there were fifty, were very clear and showed in detail the various parts of different appliances used in refrigerating plants.
 The first slide showed a chart of the pressureS of anhydrous ammonia, car bon dioxide and sulphur dioxide at given temperature. This chart showed the various favorable points of am monia and why it is used generally as the refrigerating fluid. Some of the ad- vantages and disadvantages of these three fluids are as follows: Ammonia is not explosive, has the heat of vap orization. and therefore the greatest net cooling effect per pound. It has a strong odor which makes it easy to detect leaks. 1t is very searching, and it's fumes are dangerous. It will at tack certain metals Sulphur dioxide may be sealed in the machine, mak- ing it fool proof. It acts as a lubri- cant and is neutral towards metals. It has the smallest pressure range and and the largest volume of the three. Its cooling effect is between the other two. Carbon dioxide has the smallest volume of the three, is harmless and odorless, a fire extinguisher, is neutral towards materials and food products, and its cost is about one-fourth that of ammonia It uses very high pressure, making a, very strong construction nec- essary; has the smallest heat of vaporization, and therefore the small est cooling effect.
 The Absorption System.
 Another slide showed the diagram ef an apparatus in the absorption sys- tenn using the shell type of condenser and absorber. The condenser and cool CT are the same as in the compression system. The rest of the apparatus takes the place of compressor and serves to raise low pressure Vapor to high pressure Vapor. Ammonia gas is absorbed by water in the absorber, the heat of absorption beng removed by a flow of water through the coil in the asorber. Strong liquor is then forced oy e pump to the generator or am monia still, where ammonia, vapor is driven out of solution by the heat from the steam coils. This may be low pressure steam take from an engine exhaust, heating systems or something similar. The Vapor next passes up through the tower called the analyzer, where it is cooled and the moisture is eliminated by precipitation. Practically all the remaining moisture is remOV- ed in the extension of the analyzer, called a rectifer From here high pressure ammonia vapor passes on to the condenser, then through the eX- psnsion valve, reduc.hg pressure to the cooler, where the useful work is done: then back to the absorber, completing the cycle.
 Carbon Dioxide Plant
 Another diagram showed the opera ton of the carbon dioxide refriegrating plant. The operation Is similar to that of the ammonia compression plant. The pressure is much higher, varying from 75o to 1050 pounds per square inch. The compressor discharges hot vapor through an oil trap to the condenser where it is hquefed. IL then passes through an expansion valve, where it is partially Vaporized with little or no loss of heat In expansion coils where ii is next found, vaporization is completed thereby doing the useful cooling work. It is then drawn by the compressor to it's starting point, ready for another cycle.
 Brine Cooler
 The Wolf double pipe brine cooler was also shown. In this system the ammonia is circulated through the out
 
 ner pipes. The whole coil is immersed in a brine storage tank. Thus the cool ing effect of the outer pipe surface is utilized and transmitted to the sur rounding brine solution. Brine taken from the tank by pump is forced through the inner pipes of the cooler, thence to the refrigerating room, whence 1t returns to the tank and the operation is repeated.
 Still another slide gave a view of a combined for making and refrigerat- ing plant, in which the brine system is used. The ammonia operations are the same as in previously described con- pression systems. One slide showed a photograph of a plate ice The ice measured 12 by 20 feet and was 12 inches thick, weighing seven tons. A group of men standing behind the plate ice could be distinctly seen owing to the extraordinary clearness of the ice
 The last slide showed a section Of cork board insulation for the walls of refrgerators.
 MT. Leonard closed his talk by giv- ing detailed description of the opera iron of ? new condenser which is being successfully used in the west
 The lantern was operated by George P. Thomas