GB1251785A - - Google Patents

Abstract

1,251,785. Centrifugal pumps. WESTING- HOUSE ELECTRIC CORP. Feb.23, 1970 [March 25, 1969], No.8523/70. Heading F1C. A centrifugal pump comprising a vertical shaft 16 having an impeller 17 at its lower end and a drive motor (not shown) at its upper end, and a generally cylindrical casing 11 surrounding the shaft and impeller and having a radial discharge nozzle 12 near its upper end and a suction nozzle 13 at its lower end, is characterized by a main flange 14 having a generally cylindrical neck 15 surrounding the shaft and extending downwardly inside the casing, a shaft bearing assembly 25 attached to the lower end of the neck, and one or more controlled-leakage shaft seals dispersed in the main flange above the bearing assembly. The shaft seals are retained in position by a housing 32, to which is attached a vapour seal housing 34. The leak-off liquid is removed through pipes 39, 41. To protect the bearing assembly and shaft seals from the heat of the hot liquid circulated by the pump, a cooling liquid, e. g., water, is circulated through tubes 65 disposed around the shaft 16. The cooling liquid enters and leaves via pipes 59, 61 which communicate with the tubes via passages 57, 58 in a flange 49 and semi-cylindrical pipes 60, 70 extending through the space between inner and outer walls 47, 48. Some of the liquid being pumped can flow via openings 71, 72 in the impeller 17 and a labyrinth seal 52 and, after being cooled by the cooling tubes 65, can flow via a clearance 74 into the region around the bearing assembly 25 to assist in protecting the bearing assembly and the shaft seals from the heat of the pumped liquid. In addition, liquid in the space between the walls 47, 48 is divided into layers by a number of concentric sleeves 62 to provide a thermal barrier. The casing 11 may have an internal lining of corrosion-resistant material.