Abstract: A machine for pumping liquid chlorine employs an upright shaft sump pump which is confined in a hermetically sealed housing and has a tubular supporting element surrounding the pump shaft. The latter is mounted in overhung position and is adjacent to a pressure pipe which conveys the pressurized liquid. The shaft seal is kept out of contact with the liquid by the housing as well as by a body of inert gas which is supplied to the interior of the housing and to the space between the shaft and the tubular element at a pressure depending on the pressure of inflowing liquid chlorine and being sufficiently high to prevent the inflow of liquid chlorine into the housing and/or tubular element when the pump is idle. The main impeller on the pump shaft is made integral with an auxiliary impeller which constitutes a hydrodynamic shaft seal and prevents the flow of conveyed liquid chlorine into the tubular element from below.

Abstract: A slurry feed pump which delivers a highly pressurized suspension of coal particles, coal oil and a catalyst to a liquefaction reactor is installed in a plenum chamber which is filled with pressurized coal oil and surrounds the pump housing. The suspension-supplying conduit sealingly extends into the chamber and is connected with the inlet of the pump housing, and a second conduit which delivers pressurized suspension to the reactor sealingly extends into the plenum chamber and is connected with the outlet of the pump housing. The pump is a vertical cantilevered centrifugal pump which is operated below first critical speed and its housing has holes for admission of coal oil from the plenum chamber to those parts in the pump housing which are most likely to undergo extensive wear under the action of coal particles in the suspension.

Abstract: A stuffing box which prevents the escape of highly pressurized, hot, solids-containing and/or toxic fluid media from the housing of a centrifugal pump has a receptacle with a flange which is sealingly secured to the housing and with a cylindrical portion spacedly surrounding that part of the pump shaft which extends from the housing. The receptacle contains a ring-shaped stop which is adjacent to the housing and surrounds the shaft, one or more deformable annular packings surrounding the shaft adjacent the stop, a reciprocable annular gland adjacent to the packings opposite the stop, and a sealing ring which engages the receptacle and the shaft and defines with the gland a plenum chamber for a sealing fluid. The pressure of sealing fluid exceeds the pressure of fluid medium in the pump housing, and the sealing fluid biases the gland against the packings so that the packings expand and sealingly engage the shaft and the internal surface of the cylindrical portion of the receptacle.