9 8 



THE HOUSE AX1) ITS EQUIPMENT. 



for keeping game for short perioils for daily use, the other being maintained at a temperature below 

 freezing point, so that the birds can be kept in a frozen condition for any desired period. The machine used 

 is one working on the CO- principle, which is by far the most suitable type of machine, owing to its 

 absolute safety combined with the highest efficiency. Though the type of plant is in many ways 

 similar to those described in the last chapter, it is thought well to describe it in detail, even 

 though it involves a certain amount of repetition. The action of the machine is as follows : 

 The gas is compressed in a compressor driven by an electric motor or oil engine, and while 

 under high pressure it is passed through piping which is immersed in cold water, and is known as the 

 condenser. The result of cooling the gas while under high pressure is that it becomes a liquid, and while 

 in this state it passes through a valve known as the regulator, this valve being kept almost shut so that the 

 pressure is high on one side of it and low on the other. The gas passes from the regulator through further 

 piping, and the great drop in pressure causes the liquid to suddenly evaporate into a gas again and 

 become intensely cold. This piping, known as the evaporator, is immersed in brine which cannot freeze, 

 although it is reduced man} 1 degrees below freezing point. From the evaporator piping the gas is drawn 

 back to the compressor, and it repeats the same cycle as before, no gas being used except that lost by 

 leakage. The brine cooled by the evaporator piping is circulated by a small pump to any point where 

 the cold is required. In the illustration shown the cooling appliances in the chambers consist of what are 

 known as &quot; brine drums &quot; ; these are merely large pipes through which the cold brine is passed. The 



object of having 

 them so big is to 

 keep a 1 a r g e 

 b o d y o f cold 

 brine actually in 

 the c h a m b e r , 

 which reduces 

 the temperature 

 even when the 

 m a c h i n &amp;lt; h a s 

 stopped running. 

 The quantity of 

 brine circulated 

 through the 

 brine drums in 

 each course i s 

 controlled from 

 the engine-room, 

 so that the 

 temperature can 

 be maintained at 

 any desired point 

 by varying the 

 amount of brine 



circulated. In the room used for storing birds foi a short period (where the temperature is kept above 

 freezing point) it will be noticed that means are provided for carrying away moisture deposited on the 

 drums, this being necessary because all moisture present in the air is deposited on these drums, with the 

 result that the air in the room is kept perfectly dry. Each time the door is opened and fresh goods 

 brought in, a small amount of warm air is admitted, and the moisture present in this is immediately 

 deposited on the drums. But in the chamber kept below freezing point the moisture is not carried 

 away in this manner, as owing to the low temperature it freezes solid immediately it is deposited. 



Another method of cooling the larder would be to circulate the brine through a series of pipes bent 

 into grid form and closely nested together. This stack of piping is placed immediately outside the larder, 

 and air forced over it by means of a fan is circulated through the cold room. In this case the air is 

 cooled and the moisture deposited before actually entering the room. The best method is to combine 

 this system with the one already described, so that a good ventilation is ensured and birds can be rapidly 

 cooled by means of the air-cooler. Then, when the plant stops work, the low temperature is maintained 

 by the brine drums. In constructing any cold store, great care must be taken to see that the insulation 

 is&quot; thoroughly efficient. The work of the machine is divided into two parts ; first of all, the heat has to 

 be removed from the goods brought into the store, and, secondly, the heat has to be removed which 

 passes through the walls. Now, the amount of heat which has to be removed from the goods cannot be 

 controlled ; at whatever temperature the birds come into store they must be cooled down, but the second 

 portion of the work can be controlled. If the insulation is bad, a large quantity of heat will pass through 



128. GAMEROOM AND I.ARDKR COOLED BY THE CO- METHOD. 



