8 Ward's Patent for Improvements 



The operation of the pump, delineated in sheet No. II., 

 is twofold : first, when the inlet-pipes, d, d, are in com- 

 munication with a vessel, or reservoir, to be exhausted, 

 and the pipes, p, p, in communication with the atmos- 

 phere, the operation is similar to that of the pump, de- 

 lineated in sheet No. I., and hereinbefore particularly de- 

 scribed, and to the description of which I therefore refer ; 

 and secondly, when the pipes d, d, are put in communica^ 

 tion with the traction-tube, to be exhausted, and the pipes, 

 p, p, in communication with the reservoir, previously ex- 

 hausted, the air from the traction-tube cannot pass 

 through the lower inlet- valve, f, which is held shut by its 

 rod, G, and levers, k, k, but will enter into the upper part 

 of the cylinder, a, a, by the upper inlet-valve, f, which is 

 represented open ; the air from the upper part of the 

 cylinder cannot open the upper outlet-valve, f^, which is 

 held down by the rod, g^, and the levers, k^, but the 

 lower outlet-valve being open, the lower part of the cylin- 

 der will be exhausted to the same degree as the reservoir ; 

 therefore the air from the traction-tube, pressing upon the 

 piston, will cause it to descend, thus developing consider- 

 able power in aid of that of the steam-engine with which 

 the pump is connected. When the piston descends to 

 the bottom of the pump-cylinder, the lower outlet-valve is 

 shut by the gearing, the stroke of the pump is then 

 changed, the power to pass the centre being supplied by 

 the fly-wheel, or by the steam-engine, the upper inlet- 

 valve is immediately afterwards shut, and the lower inlet- 

 valve opened simultaneously, the upper outlet-valve is then 

 released, the air from the main enters by the lower inlet- 

 valve, and the air from the upper part of the cylinder 

 passes into the reservoir, and another stroke of the pump 

 is made, and so on, the pump acting in aid of the engine 

 until the air in the reservoir becomes nearly of the same 

 density as that in the traction-tube, after which the pump 

 will require power from the engine, but will require less 

 power from it in pumping from the traction-tube into the 

 reservoir than into the air, by so much as the air in the 

 reservoir is less dense than the atmosphere. It must also 

 be observed, that in order that the air from the traction- 

 tube may not at any part of the stroke of the pump be 

 enabled to enter the inlet- valve and pass out of the outlet- 

 valve at the same end of the cylinder, without actuating 

 the piston, the gearing of the outlet-valves must be moved 



