REFRIGERATION AND REFRIGERATOR INSULATION ON BOARD SHIP. 157 
the machine, shown in Plate 78, the machine consists of a shaft with a pul- 
ley at one end, a drum at the other end, and a second drum at the middle of the 
shaft. The machine is carried in two bearings, one on either side of the central drum, 
and revolves with the central drum in contact with flowing water. 
The compressor, which is reduced to its simplest element because of its peculiar 
situation, hangs loose on the shaft inside the condenser drum and is held in position 
by means of a counterweight. 
The dumbbell is sent out from the factory completely charged and ready to op- 
erate. The air is entirely exhausted and a charge of sulphur dioxide and a pure 
neutral oil is admitted, after which the machine is hermetically sealed. The work- 
ing parts are thus constantly lubricated, and the pressure in the condenser is con- 
stantly forcing oil between the working surfaces of the compressors. 
Oxidation of the lubricating oil cannot occur as there is no oxygen present. It 
is impossible to draw air into the machine because the dumbbell is hermetically sealed. 
No dust can get access to the working parts, and, as a consequence, the wear on 
these machines is reduced to a minimum. 
The scheme of operation of the machine is undoubtedly entirely clear from an 
inspection of the drawing, except that the devices that are provided in the cold end 
of the machine for the return of lubricant from this end of the machine to the con- 
denser end, are not shown, nor the means for keeping the inner surfaces of the cold 
end of the machine thoroughly wet with the refrigerant. 
It is obvious that in a machine of this type the gas enters the compressors in 
practically a saturated condition. In consequence of this the compressors always 
operate automatically at maximum capacity, and there is no SDT ag of the 
gas with consequent loss in capacity. 
Plate 79 shows in diagrammatic form the ordinary method of arranging the 
Audifiren-Singrun Refrigerating Machine on shipboard and an assembly in more or 
less detail of the machine and brine and condenser tanks as ordinarily built for this 
service. 
The brine returning to the machine from the cooling surfaces in the refrigera- 
tor overflows from the inner tank to the outer or surge space, whence it is drawn by 
the pump and again circulated through the cooling surfaces. The arrangement of 
inner and outer tank avoids the possibility of spilling of brine with the motion of the 
ship. A similar arrangement is provided for avoiding any spilling of condensing 
water in the condenser tank. 
Where ice is required in addition to cooling refrigerators, either one of two ar- 
rangements has been used—either that shown in the diagrammatic sketch or an 
arrangement with closed coils through which the brine circulates with an auxiliary 
bath of brine in which the ice moulds are placed as shown in Plate 80. This 
latter arrangement of ice-making must, of course, be used in those cases where the 
ice-making tanks cannot be placed high enough to insure flow of the brine back to 
the evaporator or brine-cooling tank. It has the disadvantage, of course, that the 
brine has to be circulated at a lower temperature than in the case of the open 
system. 
