High pressure boiler feed water pump is medium flow, high lift, high power centrifugal pump, in order to improve the efficiency of the pump, should choose a multi-stage centrifugal pump, and choose a high speed. Impeller series, each impeller head is reduced, the specific speed increase, can improve the pump efficiency; but the series increased, bearing spacing increased, rotor stiffness decreased, should pay attention to prevent interstage ring wear or killed by danger, the pump should be promptly maintenance requirements. For example, the British Electricity Authority (CEGB) is proposed to complete the boiler feed pump in the 8h core replacement. In order to achieve this purpose, a single shell horizontal split multi-stage pump, or double shell cylinder type multi-stage pump, the pump body with a horizontal split than the use of more convenient maintenance section.
The axial force balance method of multistage centrifugal pump adopts two ways of symmetrical drum or impeller.
High pressure boiler feed pump rated power and rated speed of the product is usually greater than the APl610 standard 4 x 106 kW.r/min specified value, therefore the use of fluid dynamic pressure bearing. The radial and thrust axis takes use of tilting pad bearings. Bearing lubrication oil supply, oil system technical requirements can be carried out according to APl614 standards.
