Centrifuge with a feed device comprising a feed direction control and method of loading a centrifuge with a feed device comprising a feed direction control

Abstract

Pusher centrifuges having screen drums rotatable about axes of rotation are used for separating a mixture into solid cake and into liquid phase. Pusher centrifuges may further have pusher bases arranged in the screen drums and arranged to be movable to and fro alternately in a first pushing direction and a second pushing direction along the axis of rotation that are used in order for the solid cake to be alternately displaced along the axis of rotation. The mixture is introduced into a first empty space or into a second empty space using a feed device. The first empty space is established on a displacement of the solid cake by the pusher base in the first pushing direction and the second empty space is established on a displacement of the solid cake by the pusher base in the pushing direction opposite to the first pushing direction.

Claims

1. A centrifuge, comprising: a screen drum rotatable about an axis of rotation for separating a mixture into a solid cake and into a liquid phase, a pusher base apparatus arranged in the screen drum and configured to be movable to and fro alternately in a first pushing direction and a second pushing direction along the axis of rotation by a pusher axle connected to a pusher apparatus with a redirection control so that the solid cake is alternately displaceable along the axis of rotation, wherein the pusher base apparatus defines a first side and a second side, opposite the first side; and a feed device configured to selectively introduce the mixture into a first empty space and into a second empty space, wherein the first empty space is established on the first side of the pusher base apparatus by a displacement of the solid cake by the pusher base apparatus in the first pushing direction and the second empty space is established on the second side of the pusher base apparatus by a displacement of the solid cake by the pusher base apparatus in the second pushing direction opposite to the first pushing direction, wherein the feed device comprises a feed redirection control and a mixture supply configured so that the mixture is selectively supplied by the feed redirection control via the mixture supply to one of the first empty space or the second empty space.

2. The centrifuge in accordance with claim 1, wherein the feed device comprises an inlet pipe having an inlet pipe axis and the feed redirection control comprises a metering device provided at the inlet pipe, and wherein the mixture supply is configured to be manipulated so that a supply of the mixture into the first empty space or into the second empty space is suppressed.

3. The centrifuge in accordance with claim 2, wherein the metering device is a metering piston arranged at least partly in the inlet pipe.

4. The centrifuge in accordance with claim 2, wherein the metering device is arranged displaceable along the inlet pipe axis or rotatable about the inlet axis.

5. The centrifuge in accordance with claim 2, wherein the mixture supply is an integral component of the inlet pipe and the inlet pipe comprises a first supply opening, not movable with respect to the inlet axis, for the supply of the mixture into the first empty space and a second supply opening, not movable with respect to the inlet axis, for the supply of the mixture into the second empty space.

6. The centrifuge in accordance with claim 2, wherein the mixture supply is an integral component of the metering device and the metering device comprises a first supply opening, movable with the metering device with respect to the inlet axis, for the supply of the mixture into the first empty space and a second supply opening, movable with the metering device with respect to the inlet axis (EA), for the supply of the mixture into the second empty space.

7. The centrifuge in accordance with claim 2, wherein a plurality of mixture supplies or a plurality of metering devices are provided.

8. The centrifuge in accordance with claim 2, wherein a washing device is provided for washing the solid cake by a washing fluid, wherein the washing device is identical to the feed device or to a part of the feed device.

9. The centrifuge in accordance with claim 8, wherein a feed metering unit is provided for the controlled supply of the mixture or of the washing fluid such that a predefinable quantity of the mixture or a predefinable quantity of the washing fluid is supplied to the feed device, and/or wherein an inlet disk is provided, at the inlet pipe, for the controlled supply of the mixture into a predefinable region of the screen drum.

10. The centrifuge in accordance with claim 1, wherein the feed device comprises a plurality of inlet pipes having the feed redirection control and the mixture supply such that the mixture is supplied to the first empty space or to the second empty space.

11. The centrifuge in accordance with claim 10, wherein the mixture is supplied separately by the feed redirection control to at least some of the inlet pipes or to a group of inlet pipes.

12. The centrifuge in accordance with claim 1, wherein the feed redirection control is manipulated by a mechanical drive or of an electrical drive or of a hydraulic drive or of a pneumatic drive.

13. A method of loading a double-action pusher centrifuge in accordance with claim 1 with a mixture or with a washing fluid.

14. The centrifuge in accordance with claim 1, wherein the feed redirection control is manipulated by a mechanical drive or of an electrical drive or of a hydraulic drive or of a pneumatic drive and is controlled or regulated by a control unit.

Description

(1) The invention will be explained in more detail in the following with reference to the schematic drawing. There are shown:

(2) FIG. 1 in section, a double-action pusher centrifuge known from the prior art with acceleration surfaces;

(3) FIG. 2 a first embodiment in accordance with the invention without product washing;

(4) FIG. 3 a second embodiment in accordance with the invention with product washing;

(5) FIGS. 4a-4b a first embodiment of a metering piston;

(6) FIG. 5 a second embodiment of a metering piston; and

(7) FIGS. 6a-6c a third embodiment of a metering piston.

(8) FIG. 1 shows a double-action pusher centrifuge known from the prior at in accordance with EP 1 468 741 A1 which was already described in detail above and therefore no longer has to be discussed further at this point.

(9) FIG. 1 shows in section in a schematic representation major components of a centrifuge in accordance with the invention for the special example of a double-action centrifuge which is marked as a whole in the following by the reference numeral 1.

(10) FIG. 2 shows in a schematic representation a first embodiment of a centrifuge in accordance with the invention in an embodiment of a double-action pusher centrifuge without product washing. The double-action pusher centrifuge 1 shown in FIG. 2, which could in principle also be a singlestage or multistage pusher centrifuge or even a scraper centrifuge having a feed device 1000 in accordance with the invention, comprises in a manner known per sea screen drum 3 rotatable about an axis of rotation 2 for separating a mixture 4 into a solid cake 5 and into a liquid phase 6, a pusher base apparatus 8 which is arranged in the screen drum 3 and which is arranged movably to and fro alternately in a first pushing direction S1 and a second pushing direction S2 along the axis of rotation 2, by a pusher axle 16 connected to a pusher apparatus, such that the solid cake 5 is alternately displaceable along the axis of rotation 2. In addition, the centrifuge 1 comprises the feed device 1000 with which the mixture 4 can be introduced into a first empty space 1101 or into a second empty space 1102 which first empty space 1101 can be established on a displacement of the solid cake 5 by the pusher base apparatus 8 in the first pushing direction S1, and the second empty space 1102, which is already filled with mixture 4 in FIG. 2 or FIG. 6 respectively, can be established on a displacement of the solid cake 5 by the pusher base apparatus 8 in the pushing direction S2 opposite to the first pushing direction S1. In accordance with the present invention, the feed device 1000 comprises a feed redirection control 1020 and a mixture supply 1010 so that the mixture 4 can be supplied by means of the feed redirection control 1020 via the mixture supply 1010 to the first empty space 1101 or to the second empty space 1102 in accordance with a predefinable scheme.

(11) The feed device 1000 comprises an inlet pipe 1030 having an inlet pipe axis EA, with the feed redirection control 1020 comprising a metering device 1021, 10211 in an embodiment of a metering piston 10211 provided at the inlet pipe 1030, with the mixture supply being able to be manipulated by the metering device in accordance with a predefinable scheme such that a supply of the mixture 4 into the first empty space 1101 or into the second empty space 1102 is suppressed.

(12) This is effected in the present embodiment of FIG. 2 in that the metering piston 10211 is displaceable in the axial direction along the inlet pipe axis EA and the mixture supply 1010 is simultaneously an integral component of the inlet pipe 1030 in the form of first supply openings 1011 provided at the inlet pipe 1030 e.g. in the form of bore openings, not movable with respect to the inlet axis EA, for the supply of the mixture 4 into the first empty space 1101 and in the form of second supply openings 1012, not movable with respect to the inlet axis E1, for the supply of the mixture 4 into the second empty space 1102. In the operating state, the metering piston 10211 is controlled, for example, via the piston rod KS such that the metering piston 10211 releases the first supply openings 1011 when the pusher base 8 has released the first empty space 1101 by displacement in the direction S1 and in this respect simultaneously closes the second supply openings 1012. In the subsequent reverse stroke of the pusher base 8 in the direction S2, the metering piston 10211 releases the second supply openings 1012 and simultaneously closes the first supply openings 1011 so that the mixture is only supplied to the second empty space 1102. In this respect, an inlet disk 9, such as shown by way of example here, is provided at the inlet tube 1030 for the controlled supply of the mixture 4 into a predefinable region of the screen drum 3 in a manner known per se.

(13) It is self-explanatory that in another embodiment the piston rod KS can be replaced e.g. with a chain or with a cable control with which the metering piston 10211 can be moved or that the piston rod KS can be replaced with a suitable pneumatic, hydraulic, electric or other operational line when the corresponding drive of the metering piston is provided directly at the piston itself or at another point of the redirection control 1020. What was stated above naturally applies analogously to any embodiment of a metering device 1021, 10211, that is e.g. also to a metering bush attached outwardly about the pipe or any other type of movable metering device which, in the simplest case, can also e.g. be a flap movable with respect to the first supply opening 1011 and/or to the second supply opening 1012 or a shutter. The skilled person easily understands the equivalent solutions and possibility for the flexible or controlled release of the supply openings.

(14) A second embodiment of the present invention of great importance for practice is shown schematically with an integrated product washing with reference to FIG. 3. The washing device W for washing the solid cake 5 by means of a washing fluid F here comprises a plurality of washing nozzles WD which are arranged at an outer washing pipe WR of the feed device 1000 such that the washing fluid F can be applied onto the solid cake 5 through the washing nozzles WD for washing it. The feed device 1000 is configured as a double-walled pipe having the outer washing pipe WR and the inlet pipe 1030 arranged therein with a feed redirection control 1020. The mixture 4 is in this respect supplied to the inlet pipe 1030 arranged in the interior in a known manner, whereas the washing fluid F can be supplied via a feed metering unit D which can preferably be controlled and/or regulated to an intermediate space between the outer washing pipe WR and the inner inlet pipe 1030 and from there to the washing nozzles WD of the washing device W. The feed metering unit D is, for example, a valve which can be controlled or regulated such that the washing fluid F ca be supplied to the feed device in accordance with a predefinable scheme and in a predefinable quantity and can thus be applied to the solid cake 5.

(15) It is self-explanatory in this respect that the washing device W can also be configured in a different manner, also in a manner known per se, or that the washing device W can also be substantially identical to the feed device 1000 or part of the feed device 1000 so that, for example, the mixture 4 or the washing fluid F or also a flushing fluid for flushing the interior of the screen drum can be supplied, e.g. after one another or alternately via the feed device.

(16) FIGS. 4a-4b show a first embodiment of a metering piston 10211 in accordance with FIG. 2 or FIG. 3 a little more exactly in detail, with FIG. 4b showing a view of the metering piston 10211 from the direction R1 or R2. As can clearly be seen, the metering piston 10211 is substantially a hollow cylinder which is open at both sides and through which the piston rod KS runs axially in the center which is fastened e.g. at the front and rear end to the outer peripheral surface UK of the metering piston 10211 by a fastening cross BK. When the outer peripheral surface UK e.g. covers the first supply opening 1011, no mixture 4 can thus move through it into the screen drum 3. Conversely, when the metering piston 10211 is displaced along the axial direction S1 until the metering opening 1012 is covered, the mixture 4 can no longer move through the metering opening 1012 into the screen drum 3, but rather e.g. only through the metering opening 1011 into the first empty space 1101. In this manner, the metering of the mixture 4 can be controlled by the metering piston 10211 alternately into the first empty space 1101 and into the second empty space 1102. Since the metering piston 10211 is open at both ends, apart from the fastening cross BK, it can be moved to and fro in the axial direction without any substantial mechanical resistance through the inlet pipe 1030 fully or partly filled with mixture 4.

(17) Further embodiments of a metering piston 10211 are shown with reference to FIG. 5 and to FIGS. 6a to 6c, the metering piston here being a piston rotatable about the piston rod KS and having metering openings 1011, 1012. Such a rotatable metering piston 10211 can be rotated about the piston rod KS such that the metering openings 1011 or 1012 provided at the metering piston 10211 cooperate with metering openings 1011 or 1012 likewise provided at the inlet pipe 1030 such that mixture 4 can alternately, in dependence on the angle of rotation , be introduced thought the metering openings 1011 or through the metering openings 1012 into the screen drum 3. The metering piston 10211 in accordance with FIG. 6a in this respect differs from that in accordance with FIG. 5 substantially in that the first metering opening 1011 is offset with respect to the second metering opening 1012 by a predefinable angle of rotation in the peripheral direction and the fastening cross BK in FIG. 6 is arranged at the center of the metering piston 10211, whereas it is provided at the axial ends of the metering piston 10211 in the embodiment in accordance with FIG. 5.

(18) It is self-explanatory in this respect that the previously explained embodiment variants shown schematically in the Figures can also advantageously be combined with one another to form further embodiments to meet specific demands in practice.