Abstract:
A device is provided for treating waste water, the device including a closed housing containing at least one stack of disks through which waste water can flow. A circulating pump is provided for pumping the fluid, the pump forming a structural unit including the housing and the stack of disks arranged therein.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a Section 371 of International Application No. PCT/EP2006/002550, filed Mar. 21, 2006, which was published in the German language on Nov. 2, 2006, under International Publication No. WO 200 6/114169 A1 and the disclosure of which is incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   The invention relates to a device for fluid treatment, in particular to waste water treatment, having a circulation pump and a closed housing, in which is arranged at least one disk stack through which waste water may flow. 
   Such devices for waste water treatment, in which at least one disk stack, through which waste water flows, is arranged in a closed housing and in which the waste water is circulated by way of a circulation pump, is known from International Publication No. WO 02/094724 A1, for example. There, two disk stacks which mesh with one another and which many be moved relative to one another by way of a drive motor, in order to remove the biological coating growing on the surfaced sides of the disks to a desired extent, are arranged within a housing. Waste water flows radially through the disk stacks, which thereby is purified by the biological coating in the form of the microorganisms, adhering to the disks, i.e. the substances located in the waste water are broken down biologically. In order to convey the water through these biological filters, a circulation pump in the form of a centrifugal pump is provided, with which the waste water may be circulated within the biological filter, as well as being able to be delivered in and out of this. 
   With this known device, the disk stacks are arranged within a closed housing, wherein a drive shaft is led out to one side, via which a drive of a disk stack is effected. Pipe connections are provided at the other side, to which a circulation pump is to be connected. 
   The disadvantage with the designs described there, is the fact that they are not only expensive with regard to their construction, but furthermore also require a stationary assembly, since apart from the actual bio-filter, one also needs to provide the circulation pump assembly as well as the associated piping, which takes up much space and requires some effort with regard to construction. 
   BRIEF SUMMARY OF THE INVENTION 
   Against this background, it is an object of the invention, to provide a device of the known type, such that it may be constructed in a manner which is as space-saving as possible, and may be designed in an inexpensive and compact manner. 
   This object is achieved according to the invention by having the housing, with the disk stack located therein, and the circulation pump form a construction unit. Advantageous embodiments of the invention are specified in the following description and the drawings. 
   The device according to the invention for fluid treatment, in particular waste-water treatment, comprises a closed housing in which at least one disk stack is arranged through which waste water may flow, wherein the housing, with the disk stack located therein, and the circulation pump, which ensures the fluid circulation within the housing, form a construction unit. 
   The basic concept of the present invention is therefore to completely make do without a separate pump, and the piping between the biological filter and the pump which this requires, and instead, to design the circulation pump and the housing as a construction unit. 
   Thereby, advantageously at least a part of the pump is a constituent of the housing, in order in this manner, on the one hand to provide a space-saving design, and on the other hand to reduce the manufacturing costs and assembly costs compared to known devices. 
   Thereby, the circulation pump may either be designed in a submersing manner in the form of a submersible pump within the housing, typically into the disk stack, or only form a part of the housing, typically an end-side cover or a transverse wall. With the first solution, it is particularly advantageous for the pump to be arranged completely or at least to a great extent within the disk stack, preferably in a central cavity which is anyway only used for through-flow purposes. 
   A particularly inexpensive housing construction shape results if the housing is designed in a tubular manner, since then, the tubular part may be formed by a tube or a tube section, and one merely needs to provide covers or other terminating transverse walls on the end side. Basically, although a tubular housing may be manufactured by molding, i.e. as a cast part, the construction from a cut-to-size tube, in combination with end-side covers or a transverse wall, is often more favorable, since with this construction form one may also apply disk stacks of different size without special housing variants having to be provided for this. With a housing designed in a tubular manner, it is particularly favorable to arrange the centrifugal pump in or on a transverse wall or an end-side cover which may form the transverse wall. The circulation pump may thereby be integrated at least partly into the housing in a space-saving manner, and given a suitable design of the transverse wall, this may also form part of the pump or at least serve for fastening the pump. 
   If this transverse wall is formed by a cover closing the housing at the end-side, this has the advantage that on account of the cover, on the one hand the tubular housing is closed at the end-side, and on the other hand, the pump fastened on or in the cover may be arranged such that typically the electrical drive part is arranged outside, and the hydraulic drive part within the cover or housing. In the ideal case, one may thereby completely make do without piping, and the circulation pump may be integrated into the device in an almost ideal manner. 
   A further advantage of the cover arrangement is that after the removal of the cover from the housing, on the one hand the pump is well accessible, and on the other hand the disk stacks within the housing are also easily accessible. Usually, two or more disk stacks mesh with one another, for example in that one or more disk stacks are stationary and the other or several disk stacks may be moved relative to this. In any case, a drive for the rotation of at least one disk stack is necessary. This drive advantageously comprises a drive motor arranged outside the housing, so that the electrical components of the motor do not need to be sealed and insulated with respect to the fluid located in the housing. For this purpose, the motor is advantageously arranged on the cover in a direct or indirect manner, wherein the drive shaft is led in a sealed manner through the cover in which the centrifugal pump is arranged. Such an arrangement has the advantage that all electrical connections of the device are arranged at one side, and furthermore, the remaining housing may be designed in a comparatively inexpensive and simple manner. 
   The motor driving the pump is advantageously arranged within this cover closing the tubular housing to one side, or on this component. This arrangement too has the advantage that the motor does not come into contact with the fluid located within the housing, and all electrical connections are freely accessible from the outside. 
   It is particularly advantageous for the cover not only to serve for fastening the circulation pump, but also for the cover to form at least also a part of the pump housing, since in this manner a component, which is required anyway, may assume functions for the pump as well as for the housing of the device. 
   The cover thereby is advantageously designed of several parts, and comprises an outer cover part which closes the housing to the outside, as well as an inner cover part which closes the cover to the inside, which are connected to one another in a preferably detachable manner. The cover may assume further pump-side functions by way of this multipart construction. Furthermore, with a suitable design, one may apply components free of undercuts on account of the multipart construction, which may be manufactured inexpensively. 
   Advantageously here, the cover inner part is designed such that it forms the suction port of the pump. Here, with a suitable design of the device, one may for example connect a central channel leading through the disk stacks to the suction port of the pump in a direct manner within the housing, so that very direct and favorable flow conditions are achieved. 
   It is advantageous if an intermediate part is provided between the cover inner part and the cover outer part, the intermediate part surrounding an impeller of the pump and in which the pressure-side flow channel of the pump lies. The actual pump housing, in particular the hydraulically effective part of the pump housing, is then formed by this intermediate part. The provision of such an intermediate part is particularly favorable with regard to manufacturing technology, since then, given a suitable design, all cover components may be able to be manufactured in a comparatively simple manner, as the case may be also without undercuts. However, one may also group components together. It may therefore be advantageous to design the cover inner part and the intermediate part as one piece as a common component, which quasi forms the complete pump housing from the suction port to the pressure-side exit. 
   The intermediate part advantageously comprises an ejector, thus a jet pump, with which gas may be admixed to the pressure-side channel of the pump. Such gas is typically required with devices of this type, in order to control the biological/chemical process or maintain this. Such a gas, typically a gas containing oxygen, may be supplied to the fluid system without external energy by way of the ejector. 
   It is advantageous if the ejector comprises a first gas channel running through the cover inner part and leading into the housing, and preferably a second gas channel running through the cover outer part and leading outwards, outside the housing. Then specifically, by way of this gas channel, the upper cover inner part is connected to the inside of the housing, where a gas bubble also exists during operation of the device. At the same time, a connection to a gas reservoir, e.g., a pressurized gas bottle, is formed via the second channel from outside the housing, so that gas from the reservoir or gas from the housing may be admixed to the fluid flow, depending on the process control and requirements. 
   The housing with its middle longitudinal axis is arranged roughly horizontally, in order to ensure that the gas bubble is always arranged in the region which is connected to the ejector via the channel in the cover inner part, wherein the channel leading to the ejector and running through the cover inner part runs out in the housing at the top. 
   The cover inner part advantageously comprises a further channel which connects the inside of the housing to the pressure side of the circulation pump, wherein this channel runs out within the housing below the channel leading to the ejector and at a distance preferably below and/or next to the suction port of the pump. With such an arrangement, via the suction port of the pump, one may centrally take fluid from the middle of the disk stack and introduce it through the pressure channel into the housing again, so that this fluid to be treated flows quasi radially from the outside inwards through the disk stack or disk stacks. Thereby, by way of the arrangement of the channels to one another, one ensures that the channel leading to the ejector always runs out in the region of the gas bubble and the two other channels (suction channel and pressure channel of the pump) run out below the fluid level within the housing. 
   The cover according to the invention, which may preferably be formed of two, three or more components, may be manufactured in an inexpensive manner as a milled part or, with larger production numbers, also as a cast part to be manufactured in a coreless manner. 
   The channel arrangement in the flow direction of the pump is advantageously such that an outlet channel for gas out of the housing and an inlet opening therebehind for gas out of the reservoir run out in the pressure channel, both however preferably in front of the ejector in the flow direction. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
       FIG. 1  is a greatly simplified longitudinal sectional view of a part of the device according to an embodiment of the invention; 
       FIG. 2  is a greatly simplified longitudinal sectional view of the other part of the device shown  FIG. 1 ; and 
       FIG. 3  is a transverse sectional view through the cover along the section III-III in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The waste water treatment device represented by way of the figures comprises an essentially cylindrical housing  1 , which is formed of a tube section  2  with end covers  3  and  4 , which close the tube section  2  at the ends. 
   Whereas the disk-like cover  3  closing the tube section  2  on the right side and represented in  FIG. 2 , is formed as one piece and in a stepped manner, so that it engages with one part into the tube section  2  and with another part lies on this at the end, the cover  4 , shown in  FIG. 1  and closing the tube section  2  on the left side in the drawing, is constructed of several parts. 
   The cover  4  consists of an outer disk-like cover part (cover outer part)  5  forming the actual cover, as well as a likewise disk-like intermediate inner part and cover inner part  6 , which is releasably connected to the cover outer part  5 . The cover outer part  5 , just as the cover  3 , likewise comprises a section engaging in the tube section  2 , as well as a section bearing on this at the end, thus is designed in a stepped manner and provided with a seal  7 , as is also provided on the cover  3 , and seals the respective covers  3  and  4  with respect to the tube section  2 . 
   The fastening of the covers  3 ,  4  on the tube section  2  is effected by way of a peripheral tension strap  8 , which as a flat strip is formed with two radially inwardly pointing flanks. Of these flanks, the one engaging over the tube section  2  engages into a groove  9  at the end of the tube section  2 , while the other engages over the cover  3  and  4  on the outer side and thus fixes this on the tube section  2  with a positive fit. The tension strap  8  is equipped with a tensioning device known per se, which in a first opened position extends the strap to such an extent that the flank may be pushed over the free end of the tube section  2 , and in a second closed position tensions this, bearing tightly on the outer periphery of the tube section  2 , as well as of the associated cover  3 ,  4 , so that this is fixed with a non-positive and positive fit. 
   A disk stack, which is formed of a multitude of disks  10  arranged with a spacing next to one another, is arranged within the housing  1 . The disk stack is constructed of two sorts of disks, which in each case are arranged in an alternating manner and are designed such that, with a drive by a rack  11  provided with teeth on the other periphery, they are rotated with a different speed and about different axes, as described in detail in European patent application 04 016 525.0, which is expressly referred to inasmuch as this is concerned. There, a comparable cylinder-shaped housing, with disk stacks arranged therein and whose drive is described by way of  FIG. 6  and corresponds essentially to the present application, is shown by way of example in  FIG. 9 . 
   In any case, the disks  10  are rotatably arranged within the housing  1 , and the drive is effected via the rack  11 , which extends over essentially the whole length of the housing  1  and which engages into the outer toothings of the one of the two disk types. A tube  12  is led through central openings  20  of the disks  10  and comprises recesses, and not only serves for the removal of the fluid flowing radially inwards from the outside through the disk stack, but also as a counter bearing to the rack  12 . This tube  12  has a significantly smaller diameter than the central openings  20  in the disks  10 , so that the disks  10  of the disk stack do not roll on this tube  12  and thus do not roll about their central axis. This effect too, is described in detail in European patent application 04 016 525.0, and this is referred to inasmuch as this is concerned. 
   With an arrangement as specified, the housing  1  is aligned such that the housing longitudinal axis is arranged essentially horizontally. The waste water which is to be cleaned and is located within the housing  1  does not completely fill out the inside of the housing, but only up to a level  13 , and the space located above this is filled with gas. The disk stack is not only radially supported within the housing, but also axially supported. The waste water located therein is circulated such that it flows in at the outer periphery of the disk stack, flows radially past and between the disks  10 , and is led away again through the central recess  20  or the tube  12 , as is indicated in  FIG. 1  by the arrow representations. 
   A circulation pump  14  is provided, which is integrated in the cover  4 , in order to build up the differential pressure required for the circulation or the supply and removal of the water. The circulation pump  14  is designed as a centrifugal pump and comprises an impeller  15 , which is arranged within the cover  4 , so that the cover  4  also forms the pump housing. The impeller  15  is radially surrounded by a cover intermediate part  6   b , which in the represented embodiment is designed as one piece with a cover inner part  6   a , which closes the cover intermediate part  6   b  to the inside of the housing and forms the suction port  16  of the pump. 
   A seal  17  is provided to the inside, between the suction port  16  of the pump and the disk stack, and this seal prevents an overflow between the suction side and pressure side of the pump. A housing volute, thus a channel  18  deflecting the pressure-side flow departing radially from the impeller, and an ejector  19 , which connects thereto in the flow direction, is likewise formed within the cover intermediate part  6   b  and runs into a diffuser  20 , which via a transverse recess  21  that passes through the cover inner part  6   a , is conductively connected to the inside of the housing on the other side of the seal  17  below the level  13 , are provided in the cover intermediate part  6   b  formed by the component  6 . 
   The suction-side part of the ejector  19  forms a U-shaped channel  21 , which is represented in  FIG. 3  in dashed lines and runs out in the ejector  19  at two inlets  22 . The U-shaped channel  21  is connected via a channel  23  which passes through the component  6 , to the inside of the housing, and specifically above the water level  13 , thus in the region of the gas bubble, and via a channel  23 ′ arranged in the cover outer part  5  aligned thereto, is connected to the surroundings. The channel  23 ′ is provided for connection to a conduit, which leads to a gas reservoir, here a pressurized oxygen bottle. Thus, oxygen may be supplied to the system via the channel  23 ′. Thus, in the ejector  19  during the pump operation, either oxygen from the pressurized bottle is introduced via the channel  23 ′, or gas from the housing is introduced into the pressure-side fluid flow via the channel  23 ′, and specifically by way of the U-shaped channel  21  via the inlet openings  22 . 
   The impeller  15  of the centrifugal pump is seated on a shaft  24 , which is driven by a drive motor  25 , which is incorporated in a recess in the cover outer part  5  and is releasably fastened there. The shaft  24  carrying the impeller  15  is sealed with respect to the motor, and the motor  25  is designed as a dry runner. However, alternatively one may also use a wet-running motor, and then the sealing to the motor is effected essentially via the canned pot. 
   The cover  4  in its region at the bottom in  FIG. 1  comprises yet another recess for the drives of the rack  11 . For this, a shaft lead-through  29  is provided in the component  6 , and this is designed in a sealed manner. The one end of this shaft  26  is connected to the rack  11 , the other end to a coupling, via which the exit-side shaft of a worm gear  27  is connected, whose input shaft is connected to the drive shaft of a motor  28 , which via the gear  27  together with this is fastened on the cover  4 , in particular on the cover part  5 , and ensures a rotational drive of the rack  11 . As is evident from  FIG. 1 , the electrical connections of the drive motor  25  and the motor  28  lie outside the housing and are spatially assigned to one another, so that the electrical supply of the device may be effected from one side. 
   Not only are all electrical assemblies of the device unified in the cover  4 , but also the sensor devices required for operation. Thus, a level sensor which is required for the closed-loop control of the degree of filling of the device, is arranged within a bore  30  of the component  6 , in order on the one hand to ensure that the disk stack is completely submersed in fluid, and on the other hand that adequate free space is present for the gas bubble located in the upper region of the housing. The bore  30  passes through the cover  4 , so that the sensor may be applied and is electrically connectable from the outside. 
   Furthermore, a bore  31  is provided in the cover outer part  5 , which passes through this and runs out in the pressure channel  18  in the flow direction in front of the ejector  19 . This bore  31  serves for integrating a pressure sensor for detecting the pressure on the pressure side of the pump. The suction-side pressure is detected by way of a tube (not shown in the drawings), which runs out in the region of the suction port of the pump and is connected via a bore  32  passing through the cover  4 . A pressure sensor is likewise provided in this tube, so that the differential pressure of the pump may be detected with the help of the two pressure sensors. 
   Furthermore, a threaded bore  33 , which is sealingly closed with a screw on operation, is provided in the lower region of the cover  4 . This screw serves as a volute, after whose removal the fluid may flow out of the housing  1 . 
   Two conduit connections, which run into recesses  34  and  35  of the cover outer part  5 , are provided on the outer side of the cover  4 , in particular of the cover outer part  5 , and these connections are not visible in the drawings. The recesses  34  and  35  pass through the cover outer part  5  in a channel-like manner and run out in the cover intermediate part  6   b  within the pressure channel  18 , and specifically, seen in the flow direction, firstly the recess  35  and therebehind the recess  34 . The recess  35  serves for the removal of the water purified in the device, while the recess  34  is envisaged for the supply of the pipe water to be cleaned in the device. 
   Thus, with the design described above, all electrical sensor connections and conduit connections are integrated within the cover  4  or are arranged on this. The cover  4  in the previously described embodiment is formed of two components  5  and  6 , which are designed without undercuts and thus are favorable with regard to manufacturing technology, for example by milling/drilling from a disk of round material. Here, the component  6  may consist of two individual components  6   a  and  6   b , which bear on one another in a sealed and firm manner. 
   It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.