Page:Popular Science Monthly Volume 88.djvu/923

 Popular Science Monthly

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���weaken the metal walls of the still, which in time will cause leakage of am- monia-gas.

It may be said that any compression machine can be used with any volatile refrigerant that will boil at 30° F., or under, when exposed to the atmosphere, but in practice certain minor differences are o b - served in the con- struction of the ma- chines on account of the differ- ences in pressure of the various refriger- ants used. Inasmuch as all the machines above re- ferred to are prac- tically au- tomatic, and can be run,

and are being run, without a skilled attendant, it is hard to understand why such machines are not more generally used.

The high cost of the first installation is probably the largest obstacle to their very general use. Take a machine whose first cost is $900 and whose life is, say, ten years, you have a fixed charge of about $12.00 per month. Add to this the cost of electric current, and the cost of whatever repairs and adjustments may have to be made by skilled experts during the life of the machine, and you have a bill considerably in excess of the cost of 100 pounds of ice per day.

One of the most objectionable fea- tures urged against compression ma- chines is the noise made by the motor and compressor. P2ven when the ma- chine is located in the basement it can Ije heard over most of the house, and at times such noise is deemed very objec- tionable. Another cause of trouble is in securing a constant and even flow of cooling water to the condenser, where

��An absorption machine, though expensive to install, ought soon to repay the initial cost

��constant running cooling water is used. In many places the water supply con- tains sediment or dissolved minerals which will tend to collect under the con- trolling valve and diminish the flow of water.

Most people imagine that the tem- perature in an ordinary ice-cooled re- frigerator is lower than it really is and when they in- stall a re- f rigerat- i ng ma- chine they try to keep the tem- perature down be- low 40° F. The insu- lation in the ordi- nary re- frigerator is not suf- ficient to maintain such temperature and hence the use of electricity to run the machine will be excessive.

When the public is fully aware of the great advantages, sanitary and other- wise, of this character of cooling, over the ice-refrigerator plan, the difference in cost, it is believed, will be cheerfully accepted.

The actual cost to build a machine of this character that sells for $900 is probably not one fourth of that amount. It is fair to presume that the first cost price of all these machines will soon be materially reduced.

Unfortunately, several machines have been put on the market which were faulty in design and involved engineer- ing defects which made their failure a certainty, and these failures hav^e cast a shadow on the really meritorious ma- chines.

All the difficulties and obstacles tend- ing to prevent a commercial success of these machines are apparently capable of being overcome by engineering skill.

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