WATEE METEES 



733 



Recording 

 Mechanism 



discharge port K by way of the lower port E and the hollow piston, and 

 for the remaining half revolution the water in this space and in the outer 

 end of the piston is discharged through K, the whole cycle of operations 

 then being repeated. The action 

 becomes much more evident if a 

 tracing showing the piston be 

 rotated, keeping its correct rela- 

 tive position, through a whole 

 cycle. This meter is used ex- 

 clusively in connection with the 

 measurement of pressure water 

 from the power station of the 

 Manchester Corporation, and 

 has given excellent results. For 

 such a purpose this type has 

 the advantage that in case of a 

 breakdown the flow of water is 

 not stopped, the wastage of 

 water thus entailed being of 

 small consequence when com- 

 pared with the inconvenience 

 caused by a stoppage of the 

 power supply. 



Many types of the recipro- 

 cating piston meter have been 

 made, but space forbids the 

 mention of more than one 

 example. The " Imperial " 

 meter of Mr. Schonheyder (Fig. 

 353) consists of three single- 

 acting cylinders fitted with a 

 single hemispherical gun-metal 



~ Inlet 



Outlet 



FIG. 353. Schonheyder Positive Water Meter. 



distributing valve V bearing on 

 a vulcanite seat S. The upper 

 side of each piston is exposed 

 to inlet pressure, and according to the position of the valve the lower side 

 of each in succession is put into communication with the outlet passage. 

 The pistons are thus successively forced down and their contents discharged 

 into the outlet. At the same time one or both of the other cylinders is 

 having its piston raised, water being admitted below the piston. 



