GB975522A - Improvements in or relating to pumps and pump systems and evaporator systems - Google Patents

Abstract

975,522. Centrifugal and liquid-ring pumps. NASH ENGINEERING CO. March 14, 1961 [April 20, 1960], No. 9301/61. Heading F1C. [Also in Division B1] A pump for handling gases and vapours, or liquids, or mixtures thereof, comprises a compressor portion having at least one lobe, a compressor rotor having radially extending blades and a pair of annular end shrouds, a liquid pumping portion comprising a volute means and an impeller having impeller blades integral with one of the compressor rotor end shrouds and shaped to provide a central inlet, whereby fluid is taken in centrally from the discharge of the compressor portion and directed towards the volute means, and shaft means connected to the impeller for imparting rotation to the rotor via rotation of the impeller. A plant for distilling brine comprises an evaporator 10, Fig. 1, and a condenser 12. The evaporator may be operated by the waste heat in the cooling water of an I.C. engine. To keep the salinity within the evaporator reasonably constant, more brine is supplied to it than is needed for evaporation, the excess being withdrawn through a line 32 by a pump 30. A further pump 14, driven by the same motor 34 as the pump 30, withdraws the distillate from the bottom of the condenser 12 through a line 18 and removes any air accumulating in the condenser through a line 16. The distillate and air are both accompanied by uncondensed vapour, which condenses within the pump 14. The pump 14 discharges a mixture of distilled water and air through line 20 to a separator tank 22, where excess air is separated and vented at 24 to atmosphere. Distilled water containing a normal amount of absorbed air is delivered through a line 26. As shown in Fig. 2, the pumps 14 and 30 each comprise a liquid-ring first stage feeding a centrifugal second stage, the respective impeller blading 66 and 64 being carried by a common impeller 58. The liquid-ring stage may comprise one or several lobes, two lobes 56 being provided in the embodiment shown. Pump 30 has a single inlet but pump 14 may instead have two separate inlets 48 and 50 connected respectively to the lines 16 and 18. Some of the water is returned from tank 22 to the pump 14 through a line 28 for sealing purposes and to assist in condensing the vapour entering the pump. This pump construction is also suitable for returning hot condensate to a boiler in a process system where the pump has to handle condensate containing gas and air, the gas and air being removed from the circuit in a separation chamber.