GB1331668A - Device for balancing axial thrust on the impeller shaft of a centrifugal pump - Google Patents

Abstract

1331668 Centrifugal pumps H YOKOTA and S YOKOTA 14 Oct 1971 47809/71 Heading F1C A device for balancing axial thrust on a centrifugal pump shaft 3 comprises a lowpressure chamber 9 connected at 8 to the suction side of the pump and located axially adjacent a high-pressure chamber 7 containing at least one impeller 2, an axially-displaceable thrust drum 10 between the two chambers, a balancing disc 14 fast with the thrust drum and of greater cross-sectional area than it, and a thrust disc 15 fixed to the pump shaft, a balancing chamber 19 defined by the discs 14, 15 being in communication with the high-pressure chamber 7 through the disc 14 and the drum 10 and with the lowpressure chamber 9 through a gap 17 formed between the opposing peripheral edges 14a, 15a of the discs. The communication through the disc 14 and drum 10 takes place via an annular gap 18, an annular clearance 12 and an annular space 10c. In addition, a passage 20 may be provided. The cross-sectional area of the drum 10 is approximately equal to that of the eye of the or each impeller 2. The shaft 3 and the disc 15 are axially non-displaceable. The drum 10 and disc 14 are prevented from rotating by a lug 14c but are free to move axially until they are in equilibrium under the forces acting on them, the pressure within the balancing chamber 19 depending on the size of the gap 17 and therefore on the axial position of the drum and disc. When the pressure in the balancing chamber 9 is such that the drum 10 and disc 14 are in equilibrium, it is also such that the net force on the disc 15 balances the impeller thrust.