ON ARTIFICIAL REFRIGERATION. 



947 



Tlie upper opening is the outlet for gas in the pump, and when used 

 on an engine the inlet for steam. The large central flanged opening is 

 here shown provided with an induction valve as used in the pump in 

 order to prevent the reflux of gases towards the refrigerator. The lower 

 aperture communicates with the water-jacket. 



At the right-hand side of the drawing a bracket supiiorts one end of a 

 small shaft used only in the engine as a means of moving the cut-off by 

 the action communicated to it by the sx)iral cam on the shaft below. 



Fig. 2. 



The second illustration shows one end, cover removed and exposing 

 to view an internal cover or piston -head, which is fixed by the screws 

 shown in the drawing to the piston within. This circular cover is seen 

 to work in a recess formed by a projecting ridge ; on the cylinder in the 

 outer circumference of this circular piston-head is a cast-iron ring to 

 pack and prevent leakage. Above the piston-head is a rectangular 

 plate w^hich closes the space occui^ied internally by the slide. The other 

 parts have been referred to above, but the form of the outer cover is 

 well shown on the right-hand side of this drawing. 



The tliird engraving shows the internal arrangement after removal of 

 the inner covers. The eccentric piston with tlie x>acking-bar at its 

 periphery and the slide pressing on it above. This slide winds up and 

 down according to the position of the eccentric piston. The slide is pro- 

 vided with two channel or ports communicating with two top openings, 

 one of which is uncovered and the '^mushroom" valve removed. This 

 cover and valve are drawn on the right-hand side as shown above. 



Sufficient has been said to i^oint out very definitely the special advan- 

 tages of both engine and jiump of this novel design. 



First. The combined engine and pump are very compact and perfectly 

 self-contained. 



Second. The position of the inlet and outlet ports at separate and dis- 



