GB695434A - Multi-stage pumps - Google Patents

Abstract

695,434. Centrifugal pumps. SULZER FRERES SOC. ANON. Jan. 23, 1952 [Feb. 3, 1951], No. 1903/52. Class 110(i) In a multi-stage pump for conveying liquids at high temperatures and pressures, which is enclosed in a pressure-tight casing, an annular space between the casing and the interstage guide rings is provided with an inlet and an outlet for a preheating liquid, the inlet being provided with closing means. Guide rings 12 and inlet and discharge chambers 10, 15 are clamped between the end covers 7, 8 of the pump casing 2. The pump is preheated by passing hot water from a reservoir or boiler through an inlet pipe 30 and valve 31 into the annular space 16 between the guide rings and the casing. The hot water passes downwardly through throttling gaps 18 left between the ribs 17 of adjacent guide rings and then by way of a throttling aperture 24 into the discharge chamber 15, whence it flows through the pump to the intake 3. In addition, hot water can be passed through the pump from the discharge 4 to the intake 3. When the pump is started, valve 31 is .closed. If the pressure of the pump discharge is greater than that of the preheating water, valve 31 may be of the non-return type. In a modification, two inlets to the space 16, one on each side of a row of ribs 17, are provided at the bottom of the casing. Similarly, two outlets from the space 16 are provided at the top of the casing, in addition to or in place of the aperture 24. The inlet and outlet pipes are provided with valves. Each rib 17 may be of the full width of its guide ring, the throttling gaps being provided by staggering the ribs. The ribs may be provided on the casing. In pumps for hot oil, the space 16 may be sealed from the discharge chamber 15 to permit the use of water for preheating.