Pumps

3S79

Pumps

ally discharged from the circumference nf ihe ' displacement pump that has a rotary motion,
impeller into the casing. During its passa:^ One form is Aown in Fis. 6, in \vhich one end
through the impeller the velocity of the \\ater , cas>:nc i* removed to reveal the \\orkinc: parts,
is greatly increased, and when it is discharged > There are two shaft? which are carried in
into the casing, the energy nf motion due to j bcarincjs in the end caĞine?. On these shafts

Fig. 5. Fairbanks-Morse Duplex Power Pump.

this velocity is converted into pressure, and
the water is thus forced to considerable
heights. In addition to the services already
mentioned, centrifugal pumps are used as
fire pumps, deep-well pumps, mine pumps,

are keyed two similar rotors, each having
three lobes, and these rotate inside the pump
casing. Outside the pump the shafts are con-
nected by two gears of equal sizes Water is
admitted to the space below and between tht

Fzg. 6. Gould's Rotary Pump.

water-works pumps, and dredge pumps.

Rotary Pumps.—-Although the centrifugal

pump has a rotary motion, it is not classed

as a rotary pump. The true rotary pump is a

two rotors, which mesh like gears and turn in
opposite directions. As rotation continues, the
water is carried up and around to the dis-
charge of the pump, shown at the top.