| 摘要 |
PURPOSE:To aim at reduction of the pulsation, noise and vibration in a screw pump having a structure, in which a screw assembly consisting of a driving screw and a plurality of driven screws engaged with each other is closely fit in a sleeve, by providing a groove, both ends of which are communicating with a discharge opening, on the outer periphery surface of each threaded portion of the driven screws in the circumferential direction. CONSTITUTION:In this screw pump, a driving screw 1, having a convex side, is closely engaged on its both sides with driven screws 2, 2', having a concave side, so as to form a screw assembly, and also, said screw assembly is closely fit in a sleeve 3. One end of the driving screw 1 is supported in a removable state by a bearing 7, and is projecting outward from a casing 6, and then, an appropriate driving power source is connected to said projected part. In the above, on the outer periphery surface of each threaded portion of the driven screws 2, 2', grooves 8, 8' are provided in the circumferential direction for communicating a final sealing chamber with a discharge opening 4, such that both ends of at least one of the grooves are communicating with the discharge opening 4 all the time. Thereby, the differential pressure when the final sealing chamber 10 is open into the discharge opening 4 is caused to become smaller so that the pulsation, noise and vibration can be reduced.
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