GB1400531A - Viscosity pump - Google Patents

Abstract

1400531 Viscosity pumps PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 25 Aug 1972 [31 Aug 1971] 39730/72 Heading F1C In a viscosity pump, the rotor and the housing have a pair of co-operating surfaces in one of which is formed shallow pumping grooves which communicate at one end with a liquid inlet and at the other end with a liquid outlet, a portion of each groove adjacent the outlet being shallower than the rest of the groove so as to have a throttling effect on the flow along the groove such that a variation in the distance between the cooperating surfaces results in a pressure variation in the groove. A cylindrical rotor 1, Fig.2, comprises three pumping grooves 3 separated by lands 6, and three pumping grooves 4 separated by lands 7. Supply ports on the cylindrical housing (not shown) communicate with circumferential grooves 8, 9, each of which communicates via three axial grooves 8' or 9' with the inlet ends of the pumping grooves 3, 4. An outlet port on the housing communicates with a circumferential groove 5, which communicates via three axial grooves 10 and three axial grooves 11 with the outlet ends of the pumping grooves 3, 4. A shallow portion 22 at the outlet end of each pumping groove 3, 4 affords a restriction to flow which causes an increase or decrease in pressure in the corresponding pumping groove in the event of a decrease or increase respectively in the radial clearance between that region of the rotor and the housing, whereby displacement of the rotor from the central position produces a force tending to centralize it. The rotor may be of double-conical form, Fig.6 (not shown) or may be of disc form as shown in Fig.7. In this embodiment, spiral pumping grooves 45, 46 are provided on the housing, and there may be a gradual, rather than an abrupt, transition to the shallow portion 53 at the outlet end of each pumping groove. An inlet duct communicates via a chamber 48 with the pumping grooves 46 and via ducts 51 in the rotor 41 and a chamber 47 with the pumping grooves 45. The shallow portions 53 produce a restoring force on the rotor 41 in the event of an axial displacement. The pumping grooves 45 are formed on a plate 55 which is carried by a diaphragm 56. A liquid or pneumatic pressure exerted via a duct 58 on the underside of the diaphragm 56 tends to displace the plate 55 upwardly to reduce the clearance between the pumping grooves 45, 46 and the rotor 41, whereby the shallow portions 53 produce an increase in the pumping pressure in the grooves, this increase tending to oppose the upward displacement of the plate 55. The pumping pressure is thereby governed to be equal to the hydraulic or pneumatic pressure applied to the diaphragm and can therefore be varied by varying the latter pressure. An adjustable spring force can be used instead of a hydraulic or pneumatic pressure. In a pump having a conical rotor, Fig.8 (not shown), the pumping pressure is regulated in this manner by displacing the entire conical housing axially.