GB989832A - Improvements in or relating to flow-reversal axial-flow pumps - Google Patents

Abstract

989,832. Axial-flow pumps. ILMAINDUSTRIA LAVORAZIONE METALLI ANTIACIDI DEI F. LLI DRAGO S.a.S. Aug. 7, 1963 [Aug. 9, 1962], No. 31192/63. Heading F1C. An axial-flow pump comprises an impeller chamber which is open in axially opposite positions, the annular rear opening being connected to a substantially semi-toroidal annular chamber to deflect the flow through about 180 degrees and direct it in countercurrent to the impeller flow towards an annular opening which is coaxial with the front opening of the impeller chamber, and the impeller being adapted to rotate in either direction to cause liquid to flow in either direction. In the twostage pump shown, the pump stator comprises members A, B, C, member C affording a semitoroidal chamber which connects the impeller chamber to an annular passage coaxial with the impeller chamber and afforded by the members A, B. The pump casing is connected to a tank F by a pipe fitting G affording an inner pipe 64 connecting the impeller chamber to a diffuser 68, and an annular outer pipe 66 forming a continuation of the annular passage. Flow can be controlled by a valve H which provides a variable by-pass between the pipes 64 and 66. The electric driving motor is reversible to reverse the direction of rotation of the pump and hence the direction of flow. Where textile fibres are being dyed, washed or otherwise heated in the tank F, the reversal may take place automatically at pre-determined intervals. Instead of being curved as shown, the pipe fitting G may be of straight or other shape.