Abstract: The decanter centrifuge has a bowl with a screw conveyor having a body (4) and a screw (7). Material to be separated into a light phase is supplied through inlet ports (6) in the body, and the heavy phase is discharged through discharge ports in the bowl at one end of the conveyor. Between the inlet ports and the discharge ports for the heavy phase, the body of the screw conveyor carries a baffle (8c), generally shaped as a radial rib which forms a helical surface turning in the same direction as the screw (7). Owing to its shape the baffle actively contributes to the transport of the heavy phase, and with retention of the same gap between the baffle and the inner surface of the bowl, the gap area can be increased by increasing the axial length of the baffle.

Abstract: A decanter centrifuge including a drum that is rotatably journalled at its ends includes a separating compartment defined by end walls and a rotatably journalled conveyor disposed in the separating compartment and rotatably journalled in two bearings, one located at the free end of a trunnion projecting into the conveyor body. The separating compartment has a length to diameter ratio greater than four and the trunnion has a length in the range from 0.5 to 3 times the largest diameter of the separating compartment. Due to the short distance between the conveyor bearings, the rigidity of the conveyer increases, thereby increasing the critical RPM of the drum.

Abstract: A decanter centrifuge comprises a drum (1) with a conveyor (2) containing an inlet (4). The liquid to be separated flows in a jet centrally into the inlet (4) towards an end wall (11 ), at which the liquid is radially distributed and flows axially onwards towards the second end wall (13) through an area of the inlet (4) free of members imparting an angular velocity to the liquid. The inlet (4) is provided with inlet apertures (6) positioned on a radius larger than the radius to the overflow edge (9) at the liquid discharge. The design of the inlet (4) implies that the free liquid surface in the inlet during operation is drawn far towards the axis of the drum, thereby causing excess energy supplied to the liquid during acceleration to the angular velocity of the conveyor (2) to be dissipated in the comparatively thick liquid layer before the liquid discharges into the separation space (7) through the inlet apertures (6).

Abstract: The decanter centrifuge comprises a bowl and conveyor screw rotatably journalled within the bowl and a reduction gear providing a relative rotation of the screw relative to the bowl. The gear is journalled separately relative to the bowl in separate bearings. The housing and the driven shaft of the gear are by means of flexural but torsionally stiff couplings connected with the bowl and conveyor, respectively. The flexural couplings result in that the gear is dynamically insulated from the bowl and does not influence the critical number of revolutions thereof. As a result of this the number of revolutions of the bowl, and thus maximum allowable number of revolutions of the entire centrifuge, may be increased, thereby offering substantially improved separating properties of the centrifuge as a whole.

Abstract: The transmission comprises a hollow input member (1) and a coaxial output member (2) supported for rotation relative to the input member. A positive displacement pump comprises a cylinder block (12) secured to the input member and a rotor (16) which is journalled on an eccentric pin (17) and which drives the pump pistons (15). A positive displacement motor comprises a stator part (6) secured to the input member and a rotor part (5) secured to the output member. The motor cylinders (8) are supplied with hydraulic liquid from the pump through duct means (35, 37, 39) in a disc-shaped control member (22) journalled on the eccentric pin (17) and rotating together with the pump rotor (16). Return flow from the motor to the pump occurs through a space (28) which within the input member surrounds the control member (22) and which communicates with each pump cylinder (14) during the suction stroke of the associated pump piston (15).

Abstract: A conveyor screw includes a substantially continuous row of wear-resistant elements mounted on the wearing surface thereof. Opposed complementary semi-circular recesses are formed in adjacent wear-resistant elements providing a combined circular recess. A retaining member is received in each such recess and is secured to the conveyor screw with its axis positioned in the radial dividing line between adjacent wear-resistant elements. The gap between the retaining member and the wear-resistant elements is filled with a resilient padding material. In a modified form of the invention each wear-resistant element includes a backing plate of ductile material with each wear-resistant element being off-set relative to its corresponding backing plate. Adjacent faces of the backing plates, in lieu of being straight, are formed at an angle of approximately 175.degree. so as to provide a small gap permitting use of uniform components along a conveyor screw having a changing diameter.

Abstract: At each end the bowl of the centrifuge is journalled for rotation in a bearing housing from which the prevailing bearing loads are transmitted to a support means through a system of springs, the spring rate of which is so low that the natural frequency of the centrifuge is substantially below its normal rpm, preferably lower than 15 percent thereof. The bowl can then rotate at a high rate of rotation without concomitant vibration problems.In order to avoid undesirable transverse forces acting on the bowl a pulley mounted on its protruding shaft end may be pre-loaded in diametrically opposed directions by means of two pretensioned belt drives each of which is trained over a stationarily mounted pulley. At least one of the last mentioned pulleys is driven by a motor.

Abstract: In a stationary skimmer disc for withdrawing a liquid phase from a centrifuge there are formed one or more liquid discharge ducts each having an inlet at the outer periphery of the disc and at least one outlet located closer to the center of the disc. From a region of the flow path of the discharged liquid, where the static liquid pressure, during operation of the centrifuge, exceeds the static pressure at the inlet to the discharge duct or ducts, a by-pass duct having a throttling means intermediate its ends leads back to each of said inlets.

Abstract: A system for controlling the relative rpm. of the conveyor screw of a decanter centrifuge includes a gear interconnecting the screw and the centrifuge drum. The gear has an input shaft the rpm. of which determines the relative rpm. of the screw, and a housing rotating in synchronism with the drum. The input shaft and the housing are coupled to one each of two rotary, positive displacement machines one of which is a constant displacement machine while the other is a variable displacement machine. The machines are hydraulically connected in series in a closed circuit so that a change in the displacement volume of the variable machine, at constant rpm. of the gear housing, results in a change in the rpm. of the input shaft. The variable displacement machine may be mechanically coupled to a further constant displacement machine whereby the flow rate through the variable displacement machine is reduced to the difference between the flow rates through the other two machines.

Abstract: A horizontally journalled centrifugal rotor has support bearings at its opposite end portions resting on the bottoms of notches in respective end wall elements of a frame which also includes longitudinal elements extending on each side of the rotor and fixing the end wall elements relative to each other along their entire side edges, the support bearings having flanges parallel with the end wall elements and coacting therewith to fix the support bearings against endwise movement relative to the frame. The upper edges of the end wall elements, the longitudinal elements and the bearing flanges form together an endless contact surface disposed in a single plane and in sealing engagement with a similar contact surface of a top cover for the frame.