Abstract:
A solid material separator for separating solid particles from a mixture containing liquid and these particles which enables the process of separating the solid particles from the liquid to be improved. The solid separator comprising a collecting vessel which is movable from a filling position, wherein the mixture containing the particles and the liquid is fed into the collecting vessel, to a liquid run-off position, wherein the liquid can at least partially drain out of the collecting vessel, and a device for producing a magnetic field by means of which the particles are at least partially retained in the collecting vessel in the liquid run-off position.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
   This application is a continuation application of PCT/EP2003/012193 filed Nov. 3, 2003, the entire specification of which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to a solid material separator for separating solid particles from a mixture containing a liquid and these particles. 
   BACKGROUND OF THE INVENTION 
   Solid material separators are known in the art and are used, for example, for separating ferrite particles from a washing liquid containing the particles. In particular, such solid separators are known in the form of drum-type magnetic separators. In drum-type magnetic separators, the liquid containing the ferrite particles is fed into a container having a magnetic drum therein which is immersed in the liquid. Whilst the drum is rotating about its axis, the ferrite particles accumulate on the outer surface of the drum and are transported on said outer surface to a fixed scraper which is used to strip the particles off the outer surface of the magnetic drum. 
   A disadvantage of such drum-type magnetic separators is that liquid also adheres to the magnetic drum and is stripped off together with the ferrite particles by the scraper so that only partial separation of the particles from the liquid is achieved. 
   OBJECT OF THE INVENTION 
   An object of the present invention is to provide a solid separator which enables the process of separating the solid particles from the liquid to be improved. 
   BRIEF SUMMARY OF THE INVENTION 
   The invention provides a collecting vessel which is movable from a filling position, wherein the mixture containing the particles and the liquid is adapted to be fed into the collecting vessel, to a liquid run-off position, wherein the liquid can at least partially drain out of the collecting vessel, and a device for producing a magnetic field by means of which the particles are retained in the collecting vessel when it is in the liquid run-off position. The solid separator in accordance with the invention enables solid particles consisting of a magnetic or magnetizable material to be separated from the mixture containing the particles and a liquid in a particularly efficient manner without needing to use a filter device for this purpose. 
   The solid separator is also particularly suitable for the separation of extremely small particles from a liquid. Even in the case of particle sizes smaller than approximately 10 μm, it is possible to achieve separation of the solid particles from the liquid without the aid of filters. 
   The liquid in which the solid particles requiring separation are contained can be any type of liquid. For example, water, caustic solutions, emulsions, cooling lubricants or oils come into consideration. 
   The solid separator in accordance with the invention is especially suitable for processing liquids and slurries having ferrite constituents, as for example grey cast iron slurries, for processing washing liquids having a high particle content and for processing the concentrate from filter systems such as back-rinsing filters, ultra-filtration plants etc. 
   In a preferred embodiment of the invention, provision is made for the collecting vessel to be rotatable into the liquid run-off position from the filling position. In order to enable the separated solid matter to be discharged from the collecting vessel in a simple manner, the collecting vessel may also be moved from the liquid run-off position and/or from the filling position into a solid discharge position in which the separated solid matter is dischargeable from the collecting vessel. 
   In particular, provision may be made for the collecting vessel to be rotatable from the liquid run-off position and/or from the filling position into the solid discharge position. 
   A particularly simple method of emptying the collecting vessel is achieved if the separated solid matter is dischargeable from the collecting vessel in the solid discharge position by the effects of gravitational force. For receiving the solid matter from the collecting vessel, there is preferably provided a solid-holding container which is arranged below the collecting vessel. 
   The device for the production of the magnetic field can, in particular, comprise at least one fixed magnet element, i.e. one that does not move with the collecting vessel. Such a magnet element may be in the form of an electromagnet for example. In a preferred embodiment of the invention, however, provision is made for the at least one magnet element to be in the form of a permanent magnet element. The operational reliability of the solid separator is thereby increased. 
   In order to allow the magnetic field produced by the device for the production of the magnetic field to penetrate into the interior of the collecting vessel so that it is weakened as little as possible, provision is preferably made for the collecting vessel to be formed from a non-magnetic material. It is particularly useful if the collecting vessel is formed from a non-magnetic metallic material, for example, from a VA steel. 
   In order to enable the separated solid matter contained in the collecting vessel to be dried, provision is made in a preferred embodiment for the solid separator to comprise a heating device for heating the collecting vessel. Such a heating device can be fixed so that it does not move with the collecting vessel. In order to enable the collecting vessel to be heated in each operational phase of the solid separator, it is desirable for the collecting vessel to comprise at least one side wall which is adjacent to the heating device in each position of the collecting vessel. The heating device can be constructed in any suitable manner and may, for example, comprise an electrical resistance heating element. In a preferred embodiment of the invention, however, provision is made for the heating device to comprise a heat exchanger. In particular, the heating device may be a heat exchanger having vapour flowing therethrough. 
   To facilitate the drainage of the liquid from the collecting vessel, provision may be made for the collecting vessel to comprise a run-off wall and another wall located opposite the run-off wall, whereby, in the filling position of the collecting vessel, the average gradient of the run-off wall is less than that of the wall of the collecting vessel opposite said run-off wall. In order to prevent the liquid emerging from the collecting vessel from reaching an external wall of the collecting vessel, provision may be made for a gutter wall aligned transversely relative to the run-off wall to be arranged on an edge of the run-off wall of the collecting vessel. 
   The invention is further directed towards a liquid medium processing plant which comprises at least one solid separator in accordance with the invention and at least one vaporizing device for at least partially vaporizing the liquid that has drained out of the solid separator. Such a liquid medium processing plant enables the residual liquid that has been separated from the solid particles to be processed by the vaporization process. The condensate of the liquid medium that has been obtained from the vapour can be reused and be fed back into a liquid medium circulating system. In particular, a device for the reprocessing of aqueous, oil-containing or fat-containing cleaning solutions such as is described in DE 35 12 207 A1 can be used for the vaporizing device. 
   In order to at least partially recover the heat utilized for vaporizing the liquid that has drained out of the solid separator, it is advantageous if the solid separator comprises a heat exchanger and if the vapour from the vaporizing device is supplied at least partially to this heat exchanger. The heat exchanger can serve as a heating device for the collecting vessel of the solid separator so that the separated solids contained in the collecting vessel of the solid separator can be heated and dried by means of the heat recovered from the vapour. 
   Furthermore, in order to reduce the quantity of liquid which must be separated from the solid particles in the solid separator, provision can be made for the liquid medium processing plant to comprise at least one magnetic separator by means of which the concentration of the solid particles in the mixture supplied to the solid separator is increased. Such a magnetic separator can be constructed in the same manner as the magnetic separator described in DE 100 06 262 A1, for example. 
   These and other features and advantages of the invention will be apparent to those skilled in the art upon reading the following summary and detailed description and upon reference to the drawings 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic flow diagram of a liquid medium processing plant; 
       FIG. 2  is a schematic side view of a solid separator in the liquid medium processing plant depicted in  FIG. 1  in the filling position of the solid separator; 
       FIG. 3  is a front view of the solid separator depicted in  FIG. 2  in the filling position as seen in the direction of the arrow  3  in  FIG. 2 ; 
       FIG. 4  is a side view of the solid separator depicted in  FIG. 2  in the liquid run-off position; 
       FIG. 5  is a front view of the solid separator depicted in  FIG. 4  in the liquid run-off position as seen in the direction of the arrow  5  in  FIG. 4 ; 
       FIG. 6  is a side view of the solid separator depicted in  FIGS. 2 and 4  in the solid discharge position; and 
       FIG. 7  is a side view of the solid separator depicted in  FIG. 6  in the solid discharge position as seen in the direction of the arrow  7  in  FIG. 6 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Turning now to the drawings, a liquid medium processing plant which is illustrated in  FIG. 1  and bears the general reference  100  comprises a container  102  in which the liquid medium requiring processing, e.g. a washing liquid containing ferrite particles, is contained. A liquid supply line  104 , in which a hydraulic pump  106  and a heat exchanger  108  are arranged, leads from the container  102  to a branching point  110 . From the branching point  110 , a first supply line  112   a  which is blockable by means of a non-return valve  114   a  leads to an inlet of a first magnetic separator  116   a , whilst a second supply line  112   b  which is blockable by means of a non-return valve  114   b  leads to an inlet of a second magnetic separator  116   b.    
   The first magnetic separator  116   a  comprises a base body  118  which itself comprises an upper cylindrical section  120  and a lower, downwardly tapering conical section  122 . The upper end of the base body  118  is closed by a cover  124  from whose lower surface extends an inner pipe  126  that is coaxial with the upper section  120  of the base body  118  and protrudes into the interior of the base body  118  which forms a collecting chamber  128 . A flap valve  130  is arranged at the lower end of the base body  118 . A sluice chamber  132  that is arranged below the flap valve  130  is separable from the collecting chamber  128  by means of said flap valve. A slide valve  134  is arranged at the lower end of the sluice chamber  132  and an outlet pipe  136  is arranged below the slide valve  134  being separable from the sluice chamber  132  by means of said slide valve. 
   Furthermore, the first magnetic separator  116   a  comprises a plurality of magnet elements  138  that are adapted to be moved from a rest position which is illustrated in  FIG. 1  wherein the magnet elements  138  are spaced from the base body  118 , into a working position wherein the magnet elements  138  rest against the base body  118  of the magnetic separator. This is illustrated in  FIG. 1  with the aid of the second magnetic separator  116   b . The base body  118  may be formed from a non-magnetic metallic material, e.g. a VA steel, so that the magnetic field produced by the magnet elements  138  extends into the collecting chamber  128  when the magnet elements  138  are in the working position. 
   In the upper section  120  of the base body  118  of the first magnetic separator  116   a  there is provided an outlet from which a first removal line  140   a , which is blockable by means of a non-return valve  142   a , leads to a junction point  144 . The second magnetic separator  116   b  is constructed in exactly the same way as the previously described first magnetic separator  116   a  and it comprises an outlet that is connected via a second removal line  140   b , which is blockable by means of a non-return valve  142   b , to the junction point  144 . Thus, the two magnetic separators  116   a ,  116   b  are connected in parallel and the liquid medium requiring processing flows through them alternately from the container  102  when the liquid medium processing plant  100  is in operation. 
   As illustrated in  FIG. 1 , the non-return valves  114   a  and  142   a  are closed whereas the non-return valves  114   b  and  142   b  are open so that the liquid medium being pumped out of the container  102  by the hydraulic pump  106  flows back into the container  102  via the heat exchanger  108  and the collecting chamber  128  of the second magnetic separator  116   b  and from there via the junction point  144  and a liquid return line  146 . The direction of flow of the liquid medium is indicated in  FIG. 1  by the arrows  147 . 
   In  FIG. 1 , the second magnetic separator  116   b  is in a collecting phase wherein the magnet elements  138  are arranged in their working position on the base body  118  so that the ferrite particles contained in the liquid medium flowing through the collecting chamber  128  are retained within a collecting region  148  which is surrounded by the magnet elements  138 . The collecting phase of the second magnetic separator  116   b  is terminated when the volume of the particle slurry  150  that has collected in the collecting region  148  of the second magnetic separator  116   b  is such that it almost corresponds to the internal volume of the sluice chamber  132 . 
   The non-return valves  114   b  and  142   b  are closed and the non-return valves  114   a  and  142   a  are opened so that the liquid medium now flows out of the container  102  through the first magnetic separator  116   a . Thus, the first magnetic separator  116   a  enters its collecting phase wherein the magnet elements  138  are in their working position on the base body  118 . Meanwhile, the second magnetic separator  116   b  enters into a sedimentation phase wherein the magnet elements  138  are moved from their working position into their rest position where they no longer retain the ferrite particles in the collecting region  148 . Then the flap valve  130  is opened whereby air cushions present at the upper end of the collecting chamber  128  decay and a pulse-like movement is triggered in the fluid column located below the air cushions so that the ferrite particles are thereby expelled substantially in their entirety from the collecting region  148  within the interior of the base body  118 . The displaced particles sink downwardly through the collecting chamber  128  due to the effects of the force of gravity and enter the sluice chamber  132  through the opened flap valve  130 , the lower end of said chamber being closed by the slide valve  134 . 
   The sedimentation phase of the second magnetic separator  116   b  is terminated by the closure of the flap valve  130  as soon as substantially all of the particle slurry  150  that was displaced from the collecting region  148  has entered the sluice chamber  132 . In the following delivery phase of the second magnetic separator  116   b , the slide valve  134  is opened so that the particles that are contained in the sluice chamber  132  and the residual liquid from the collecting chamber  128  will fall downwardly through the outlet pipe  136 . 
   When the first magnetic separator  116   a  has terminated its collecting phase, the second magnetic separator  116   b  is switched back into its collecting phase and a new operational cycle of the second magnetic separator  116   b  begins. 
   Under each of the magnetic separators  116   a ,  116   b , there is arranged a respective solid separator  152  which serves for separating the particles arriving via the outlet pipe  136  from the accompanying liquid. This process will be described in more detail hereinafter with reference to  FIGS. 2 to 7 . 
   Each solid separator  152  comprises a collecting vessel  154  which consists of two substantially flat, mutually parallel side walls  158  which are spaced from one another along a rotational axis  156  of the collecting vessel  154  and are constructed so as to be substantially congruent to each other. The two side walls  158  are connected together by means of a bottom wall  160  which is aligned substantially radially relative to the axis of rotation  156 , a front wall  162  which extends from a radially outer end of the bottom wall  160  and is substantially perpendicular to the bottom wall  160 , a rearward run-off wall  164  which extends from the radially inner end of the bottom wall  160  and includes an obtuse angle a with the upper surface of the bottom wall  160 , and a gutter wall  166  which adjoins the outer end of the run-off wall  164  that is remote from the bottom wall  160  and extends substantially perpendicularly downwards from the run-off wall  164 . The bottom wall  160 , the front wall  162 , the run-off wall  164  and the gutter wall  166  together with the regions of the side walls  158  connecting the front wall  162  to the run-off wall  164  form a collecting tank  168  which incorporates a passage opening  170  at the side thereof located above the bottom wall  160 , said opening being bounded by the top edges of the front wall  162  and the run-off wall  164  and by the two side walls  158 . 
   As can best be seen from  FIG. 3 , there extends outwardly along the axis of rotation  156  from the outer surface of the side wall  158   a  illustrated on the left in  FIG. 3  a first rotary shaft part  172   a  which is mounted in a (merely schematically illustrated) first bearing  174   a  such as to be rotatable about the axis of rotation  156 . Similarly, there extends outwardly along the axis of rotation  156  from the outer surface of the side wall  158   b  illustrated on the right in  FIG. 3  a second rotary shaft part  172   b  which is mounted in a second bearing  174   b  such as to be rotatable about the axis of rotation  156 . The outer end of the second rotary shaft part  172   b  is engaged by a rotary drive device  176  with the aid of which the rotary shaft part  172   b  and hence the further elements of the collecting vessel  154  that are rigidly connected to the rotary shaft part  172   b  are rotatable about the axis of rotation  156 . 
   A fixed (upwardly open) solid-holding container  178  is arranged below the collecting vessel  154 . A collecting funnel  182  (partially illustrated in  FIGS. 2 ,  4  and  6 ) for the liquid draining out of the collecting tank  178  is arranged at the top edge of a rear wall  180  of the solid-holding container  178 . At an upper end of the collecting funnel  182 , there is a stop member  184  which is arranged between the side walls  158  of the collecting vessel  154  and serves to limit the rotational path of the collecting vessel  154 . The stop member  184  may consist of a resilient material in order to absorb the impact of the collecting vessel  154  on the stop member  184 . 
   Furthermore, the solid separator  152  incorporates a heating device  186  which is arranged statically between the side walls  158  of the collecting vessel  154  and comprises two lateral heating surfaces  188  that are in contact respectively with the inner surface of the neighbouring side wall  158  of the collecting vessel  154 , and an upper heating surface  189  that is in contact with the outer surface of the run-off wall  164  in the liquid run-off position of the collecting vessel  154 . Heat can be transferred from the heating device  186  to the side walls  158  (which are rotatable relative to the heating device  186 ) via these heating surfaces  188 . In the exemplary embodiment described here, the heating device  186  is in the form of a heat exchanger having vapour flowing therethrough. 
   The solid separator  152  comprises a plurality of magnet elements  190  that are arranged in two substantially horizontal rows extending above the axis of rotation  156  of the collecting vessel  154  at both sides of the collecting vessel  154  and adjacent to the outer surfaces of the side walls  158 . The collecting vessel  154  consists of a non-magnetic metallic material, e.g. a VA steel, so that the magnetic field produced by the magnet elements  190  extends into the space formed between the side walls  158  of the collecting vessel  154 . The magnet elements  190  may be in the form of permanent magnets. The collecting vessel  154  can be moved into three different working positions by means of the rotary drive device  176 , namely, a filling position which is illustrated in  FIGS. 2 and 3 , a liquid run-off position which is illustrated in  FIGS. 4 and 5  and a solid discharge position which is illustrated in  FIGS. 6 and 7 . 
   In the filling position illustrated in  FIGS. 2 and 3 , the collecting vessel  154  is aligned in such a way that the bottom wall  160  of the collecting tank  168  is aligned substantially horizontally and the longitudinal axis of the outlet pipe  136  that is arranged above the solid separator  152 . Emanates from the respective magnetic separators  116   a  and  116   b  associated with the solid separator  152  are directed between the side walls  158  of the collecting vessel  154  toward the passage opening  170  of the collecting tank  168 . The collecting vessel  154  is moved into the filling position before the slide valve  134  of the respective magnetic separator  116   a  or  116   b  arranged above the solid separator  152  is opened. After the opening of the slide valve  134 , the particles that are contained in the sluice chamber  132  of the relevant magnetic separator as well as the liquid that is contained in the sluice chamber  132  both enter the collecting tank  168  via the outlet pipe  136 . 
   The collecting vessel  154  remains in the filling position for several delivery phases of the associated magnetic separator, namely, until the filling level  192  of the collecting tank  168  has almost reached the top edge of the front wall  162  or that of the run-off wall  164 . The ferrite particles that are filled into the collecting tank  168  during this filling phase adhere to the side walls of the collecting tank  168  due to the effect of the magnetic field produced by the magnet elements  190 . When the maximum filling level of the collecting tank  168  has been reached, the collecting vessel  154  is rotated slowly counter clockwise (as viewed in  FIG. 2 ) by means of the rotary drive device  176  from the filling position into the liquid run-off position illustrated in  FIGS. 4 and 5 . The run-off wall  164  of the collecting tank  168  rests against the upper heating surface  189  of the heating device  186  and is thus inclined to the horizontal in such a way that the radially outer edge thereof lies below the edge of the run-off wall  164  adjoining the bottom wall  160  so that, in this position, the gradient of the run-off wall  164  slopes toward the gutter wall  166 . In this liquid run-off position, the liquid contained in the collecting tank  168  therefore flows out of the collecting tank  168  and into the collecting funnel  182  over the run-off wall  164  and the gutter wall  166 . 
   Due to the effect, however, of the magnetic field which is produced by the magnet elements  190 , the ferrite particles contained in the collecting tank  168  are retained on the side walls  158  of the collecting tank  168  even in the liquid run-off position so that they do not enter the collecting funnel  182 . After substantially all of the liquid has drained out of the collecting tank  168 , the collecting vessel  154  is heated by means of the heating device  186  so that the solids remaining in the collecting tank  168  are dried. 
   After the passage of a given period of time in the liquid run-off position that is sufficient for the desired process of drying the solids in the collecting tank  168 , the collecting vessel is moved in the clockwise direction (as viewed in  FIG. 4 ) by means of the rotary drive device  176  from the liquid run-off position into the solid discharge position illustrated in  FIGS. 6 and 7 . The base of the bottom wall  160  of the collecting tank  168  rests on the stop member  184  and the passage opening  170  of the collecting tank  168  is directed downwardly so that the solid particles enter the solid-holding container  178  from the collecting tank  168  through the passage opening  170  under the effects of the force of gravity. In the solid discharge position, the entire collecting tank  168  is below the axis of rotation  156  of the collecting vessel  154  where there are no magnet elements  190  so that the ferrite particles are not retained on the side walls of the collecting tank  168  by a magnetic field in the solid discharge position. 
   Following the process of substantially completely emptying the collecting tank  168 , the collecting vessel  154  is rotated back into the previously described filling position in a counter-clockwise direction (as viewed in  FIG. 2 ) by means of the rotary drive device  176  in order to receive fresh solid particles and liquid. As can be seen from  FIG. 1 , the collecting funnels  182  associated with the solid separators  152  are each connected via a liquid removal line  194   a ,  194   b  to a junction point  196 , from where a supply line  198  leads to an inlet of an evaporator  200 . The supply line flows into a boiling zone  202  of the evaporator  200  which is separated from an oil collecting area  204  of the evaporator by a partition  206  having an overflow  208 . The boiling zone  202  is filled with a liquid bath  212  up to a bath level  210 , a heating device  214  being immersed in said bath for heating the liquid in the liquid bath  212  to beyond its boiling point. 
   The non-magnetic solid particles which were not retained in the collecting vessels  154  and which entered the boiling zone  202  of the evaporator  200  with the liquid drained from the solid separators  152  settle on the bottom of the boiling zone  202  and can be removed therefrom via a valve  216 . Oily constituents of the liquid emerging from the solid separators  152  form an oil film on the top surface of the liquid bath  212  due to their smaller specific weight, and from there, this oily phase enters the oil collecting area  204  of the evaporator  200  over the overflow  208 . 
   The vapour of the liquid requiring processing that was formed by vaporizing the liquid in the liquid bath  212  enters a vapour removal line  218  via an outlet located in the top surface of the evaporator  200 . Said vapour then enters the vapour side of the heat exchanger  108  wherein the heat of the vapour is transferred to the liquid medium being pumped from the container  102  and the vapour thereby condenses. The condensate from the heat exchanger  108  is fed into a condensate collecting vessel  222  via a condensate line  220 . Vapour branching lines  224   a ,  224   b  branch off the vapour removal line  218  so that the vapour can be supplied via said branching lines from the vapour removal line  218  to the heating devices  186  of the collecting vessel  154  which are in the form of heat exchangers. 
   In the heating devices  186 , the heat of the vapour is transferred to the collecting vessels  154  of the solid separators  152  for the purposes of drying the solids in the collecting tubs  168  and the vapour thereby condenses. The condensate reaches a junction point  228  via the condensate removal lines  226   a ,  226   b , and from there, a condensate line  230  leads to the condensate collecting vessel  222 . The condensate is transferred from the condensate collecting vessel  222  to the container  102  via a condensate return line  230  having a condensate pump  232  arranged therein. Thus, a liquid medium requiring purification is continuously extracted from the container  102  and the purified liquid medium is returned thereto via the fluid return line  146  whilst the reprocessed condensate from the distillation process is also returned thereto from the condensate collecting vessel  222  via the condensate return line  230 . It is in this manner that the liquid medium in the container  102  is continuously cleaned and reprocessed. The directions of flow of the liquid draining from the solid separators  152 , of the vapour escaping from the evaporator  200  and of the condensate being fed back from the heat exchangers  108 ,  186  are indicated by the arrow  232  in  FIG. 1 . 
   It will be appreciated by those of skill in the art that the particular design of the solid material separator may be of an alternate configuration than those disclosed in the illustrations herein. While this invention has been described with an emphasis upon preferred embodiments, variations of the preferred embodiments can be used, and it is intended that the invention can be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications encompassed within the spirit and scope of the invention as defined by the following claims. For example, various aspects of the invention may be practiced simultaneously. 
   All of the references cited herein, including patents, patent applications, and publications, are hereby incorporated in their entireties by reference.