PUMPS 513 
of the revolving water causes it to travel outwards from the centre to the 
cireumference of the wheel. The suction or supply pipe leads the water 
to the centre of the wheel, and the delivery pipe takes it from the casing 
at the circumference of the wheel. The centrifugal pump is to a certain 
extent a reversed turbine, and the principles involved in the theory of 
the centrifugal pump are the same as for that of the turbine. 
Fig. 823 shows a type of centrifugal pump made by Messrs. W. H. 
Allen, Son, & Co., of Bedford, who kindly supplied the drawings from 
Fig. 823. 
which this illustration has been prepared. A is the wheel, which is of 
the shrouded type, provided with six vanes B between the shrouds. For 
pumping ordinary water the wheel may be made of cast-iron, but for salt 
or brackish water a gun-metal wheel is generally used. The wheel is 
keyed to a steel or bronze shaft C, which runs in white metal bearings D 
carried by the easing. Where the shaft leaves the casing there is a gland 
and stuffing box to prevent leakage. The water enters from the suction 
pipe connected to the pump casing at E, and flows to both sides of the 
wheel, entering the latter at its eye or centre opening. Passing through 
the wheel the water flows into the expanding chamber F, and thence into 
2K 
