| 摘要 |
1,166,859. Centrifugal separators. ALFALAVAL A.B. 5 Dec., 1966 [15 Dec., 1965], No. 54280/66. Heading B2P. Intermittent sludge discharge through openings 3 in a centrifuge rotor 1 is controlled by an axially movable first valve 4 actuated hydraulically, an outlet 9 for the valve-operating liquid being controlled by a second valve 11 which is permanently biassed by a spring 12 to close the outlet and which is arranged to be opened by direct electromagnetic action. The valve-operating liquid is supplied via a channel 5 and passages 6, 7 to a space 8 from which it may be discharged through a number of outlets 9 provided at their outer openings with nylon tubular peds 10 against which the valve 11 is biassed. The valve-opening electromagnetic means may be provided on the rotor and operated by stationary devices. Preferably, as shown, one (annular) or more (peripherally distributed) electromagnets 14 are mounted on the centrifuge frame 13 around the rotor shaft 2. In its fully open position, the valve 11 abuts against a step 15 solid with the shaft 2 so that a gap is provided between the rotating valve and the stationary magnet cores 16. The valve 11 and hence the valve 4 are arranged to be kept open for a predetermined period by means of a timer controlling the energisation of the electromagnets. In one embodiment, Fig. 2 (not shown) the timer may be in the form of a rotating cam disc driven by a motor, the cam being adapted to close or open a switch in the electrical circuit incorporating the windings of the electromagnets. Rotation of the cam disc may be started after a predetermined time or through an impulse from a sludge-level-sensing means. In another embodiment, Fig. 3 (not shown), the timer is in the form of a capacitor connected in parallel with the windings of the electromagnets and arranged upon actuation of a switch to discharge through the windings during a period of time corresponding to that of sludge discharge. |
