106 SMALL WATER SUPPLIES. 



when inquiring or ordering, and full particulars of 

 the fuel should be given, together with an analysis if 

 possible, as in many cases it is necessary to modify 

 the generator, and provide a special scrubber ar- 

 rangement, etc. 



Much interest is at present being displayed at the 

 time of writing in a pump which utilizes the direct 

 pressure of an explosion of gas on the surface of a 

 volume of water for pumping it. The pump acting 

 on this principle is known as the Humphrey pump, 

 and in a paper read by the inventor, Mr. H. A. 

 Humphrey, before the Manchester Association of 

 Engineers on n October, 1910, it was described as 

 follows. 



Figs. Sia and Sib show alternative arrangements 

 of the top of the combustion chamber for a two- 

 cycle pump. It will be observed that the combustion 

 chamber has to be specially shaped, so that the in- 

 coming charge, which may be preceded by pure air, 

 displaces the burnt products and mixes as little as 

 possible with them. Thus, in fig. Si a, A is the 

 admission valve at the top of the tall, narrow part of 

 the chamber B, in which the full charge volume ex- 

 tends down to the level C C. A number of exhaust 

 valves E lead to a common exhaust outlet O, which 

 may be fitted with a non-return valve, or each ex- 

 haust valve may carry a light non-return valve on its 

 spindle, as shown. The level at which expansion 

 reaches atmospheric pressures is, say // but this 

 level having been reached by the water, its further 

 movement draws in fresh combustible mixture till it 

 occupies the space down to C C, and the liquid level 

 has fallen to g g. The column of liquid now returns 



