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Special Pumps

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Figure 9.17: AODD pump (Reproduced with permission of ProSpec Technologies Inc.)

9.4.3 The gear and lobe pump
The external Rotary Gear Pump is a positive displacement pump where
the unmeshing of the gears produces a partial vacuum to draw the
liquid into the pump. The liquid carried between the gear teeth and the
casing to the opposite side of the pump where the meshing of the gears
forces the liquid through the outlet port. The direction of rotation
determines which of the nozzles will be the inlet and which will be the
outlet. Therefore, by reversing rotation, the pump will be able to pump
backwards.

Figure 9.18: External gear pump (Reproduced with permission of Roper Pump Company)

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