Abstract:
A water treatment device, having a housing with duct areas which are used to conduct the water to be treated. At least a first and a second electrode are accommodated in the housing. The first and second electrodes are alternately positive-poled and negative-poled. Electro-conductive material is introduced into the housing. In order to provide a water treatment device which can be operated on a permanent basis with a high degree of efficiency, the first and second electrodes are arranged in separate first and second electrode chambers which are insulated from each other by one or several insulating bodies, the electrode chambers are respectively filled with a bulk material of a uniform granulated material, and the insulating bodies are pervious to water to be treated but are impervious to the granulates forming the bulk material.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a device for treating water, having a housing with conduit areas for conducting the water to be treated, wherein at least one first and one second electrode is arranged in the housing, the first and second electrodes are alternatively positively and negatively polarized, and an electrically conductive bulk material is placed into the housing.  
           [0003]    2. Discussion of Related Art  
           [0004]    A conventional device is known from PCT International Publication WO 98/16477. This device is used for reducing, or preventing, the formation of scale in aqueous solutions. A housing is used, into which a cartridge is inserted. The cartridge has two electrodes, each of which is arranged in an electrode chamber. A bipolar electrode is arranged in the area between the electrodes, which is embodied as a fixed bed. The fixed bed is formed by a bulk material which has electrically conducting carbon particles and non-conducting insulating particles, for example pebbles, glass or plastic bodies. The non-conducting insulating particles insulate the carbon particles from each other, so that the formation of short circuits is prevented. A voltage is applied to the bipolar electrode via the electrodes. During this the individual carbon particles are given a positive and a negative charge. The liquid to be treated is conducted through the bipolar electrode. The calcium contained in the liquid is precipitated in the form of calcite at the negative pole areas of the carbon particles. To prevent a calcite deposit in this pole area, the polarity of the electrodes is regularly reversed.  
           [0005]    An even blending process in the bipolar electrode, and therefore the even distribution of the conducting and non-conducting particles, is important for this known arrangement. However, in actual use it has been shown that a segregation occurs in the bipolar electrode, for example in connection with its transportation or partially during its operational use. It then loses its effectiveness and the efficiency is drastically reduced.  
         SUMMARY OF THE INVENTION  
         [0006]    It is one object of this invention to provide a device of the type mentioned above but which can be operated long term at high efficiency.  
           [0007]    This object is achieved with the first and second electrodes housed in first and second electrode chambers, which are separated from each other and are electrically insulated from each other by one or several insulating bodies. Each of the electrode chambers is filled by bulk material of a uniform granulate, and the insulating bodies are permeable to the water to be treated, but impermeable to the granulated bulk material. Polarized areas are created in the electrode chambers, in which a single fixed polarization exists for a defined length of time. With this division into unipolar areas, the homogeneously composed bulk material of this invention can be used, wherein a segregation as in the prior art is not a problem. It is thus possible to assure dependable operation because of this combination of characteristics.  
           [0008]    The bulk material can include, for example, granulated carbon, in particular activated charcoal, which is introduced into the electrode chamber in the form of a fixed bed.  
           [0009]    In accordance with a preferred embodiment of this invention the insulating bodies are formed as bulkhead walls and have a screen-like passage area for the water to be treated, wherein the sizes of the openings forming the passage areas are less than the granule diameters of the particles of the bulk material.  
           [0010]    In order to achieve the greatest possible flow introduction into the bulk material, the first and second electrodes can be embodied rod-like and can be surrounded over their entire length by the bulk material.  
           [0011]    In one embodiment of this invention, a conduit area which is surrounded by an area which receives the electrode chambers is arranged in the housing. The conduit area is in spatial connection with the electrode chambers via the openings, and the side of the electrode chambers which faces away from the conduit area in the radial direction is covered by a liquid-permeable shell. A conduit section adjoins the shell in the housing. In this case, the conduit area can be selected such that initially the water to be treated is introduced through the central conduit section and then flows through the electrode chambers and the peripheral conduit area. However, a reverse flow is also conceivable. A re-mixing of the electrolysis products resulting from the treatment is avoided with these types of flow conduction.  
           [0012]    A device in accordance with this invention is distinguished because the electrode chambers are separated from each other by insulating bodies which substantially extend in the flow direction of the water to be treated. In this case the liquid to be treated flows parallel through the individual electrode chambers.  
           [0013]    It is also possible to connect the electrode chambers in series so that they are separated from each other by insulating bodies extending transversely with respect to the flow direction of the water to be treated, and the electrode chambers are arranged one behind the other in the flow direction.  
           [0014]    A combination of parallel and series connection is also conceivable.  
           [0015]    For preventing an impermissible nitrite formation in the water, in a further embodiment of this invention, viewed in the flow direction, an oxidation zone, through which the water treated in the associated electrode chamber, or in several electrode chambers is conducted, is arranged behind at least one of the electrode chambers. A fixed bed electrode which, for example, includes carbon particles and has a positive polarity, can be connected downstream as the oxidation zone.  
           [0016]    A calcite precipitation takes place only near or in the area of the negatively polarized electrode chambers during the operation. For achieving the greatest possible efficiency, a device in accordance with this invention can be designed so that different volume flows of the water to be treated flow through the electrode chambers of different polarization. Alternatively, or additionally, the length of polarization of the cathodic and the anodic phases of at least one of the electrodes is selected to be different. In this case the water to be treated remains longer in the electrode chamber with negative polarization.  
           [0017]    For achieving the greatest possible even flow density in the electrode chambers, a device can be designed so that the electrodes are arranged at least partially concentrically with respect to the conduit area arranged in the housing. The electrodes, which are arranged on a graduated circle around the conduit area are distributed equidistantly with respect to each other in the ambient direction. For achieving an improved calcite crystal formation, the water to be treated flows through a magnetic treatment device prior to entering the housing. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    This invention is explained in greater detail in view of embodiments shown in the drawings, wherein:  
         [0019]    [0019]FIG. 1 shows a device for the treatment of water in a lateral view and in vertical section;  
         [0020]    [0020]FIG. 2 shows the device in FIG. 1 but in horizontal section; and  
         [0021]    [0021]FIG. 3 is a horizontal section taken through another embodiment of a device for the treatment of water, which differs from FIGS. 1 and 2. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0022]    A device, for the treatment of water, which has a tube-shaped housing  25  is shown in FIG. 1. In its bottom area, the tube-shaped housing  25  is closed off by a support  10 . The support  10  has a flange plate  11  which is in contact with the lower front face of the housing  25 . The flange plate  11  forms a collar  12 , on which the front face of the housing  25  is seated. A seal  13  is arranged near or in the area of the collar  12 . The seal  13  seals the interior of the housing  25  against the surroundings. In the area adjoining the collar  12 , the support  10  has a shoulder  14 . The shoulder  14  is used for receiving a tube-shaped shell  23 . The tube-shaped shell  23  is centered and aligned on a cylindrical protrusion  15  of the support  10 . The protrusion  15  projects into the interior surrounded by the shell  23 . A conduit section  20  is arranged in the center of the shell  23  and is the form of a tube. In its casing, the conduit section  20  has a plurality of openings. The conduit section  20  is maintained on a blind bore  18  of the support  10 . As shown in FIG. 2, four electrodes  22 . 1 ,  22 . 2  are arranged in the area between the conduit section  20  and the shell  23 . In this case the electrodes  22 . 1 ,  22 . 2  are arranged concentrically with respect to the conduit section  20 , and each is offset by 90° from the other. The support  10  has electrode seats  17  in the form of bores for fixing the electrodes  22 . 1 ,  22 . 2  in place. Contacting the electrodes  22 . 1 ,  22 . 2  takes place via contact springs  19 . 2 , which are inserted in a threaded receiver  16  which terminates in the electrode seat  17 . A contacting element  19 . 1  is screwed into the threaded receiver  16  and presses the contact springs  19 . 2  against the electrodes  22 . 1 ,  22 . 2  and can be connected to a power supply on the exterior of the housing  25 . The remaining annular space between the conduit section  20  and the shell  23  is filled with a bulk material of electrically conductive material, for example activated charcoal. As mentioned above, the conduit section  20  has openings and is therefore embodied in a screen-like manner. The shell  23  is also embodied in a screen-like manner. The openings of the screens are of such a size that the particles of the bulk material cannot leave the space between the shell  23  and the conduit section  20 , but that an electrical insulation between the adjoining areas is assured.  
         [0023]    As FIG. 1 further shows, a cap  30  is pushed on the head of the shell  23 . The cap  30  has a shoulder  33  for this purpose, which receives the front face of the shell  23 . Furthermore, the cap  30  has electrode seats  34 , which are embodied in the manner of a blind bore and in which the ends of the electrodes  22 . 1 ,  22 . 2  are received. A conduit section  36  passes through the center of the cap  30  and terminates in a widened seat  35 . The end of the conduit section  20  is received in the seat  35 . On its side facing away from the conduit section  20 , the cap  30  has a shoulder  31 , on which a cover  40  is sealingly held by a seal  32 . The cover  40  encloses an outer chamber  41 , which is spatially connected with a conduit area  24  formed between the housing  25  and the shell  23 . The cover  40  has an inner chamber  42 , which is spatially connected with the conduit section  36  of the cap  30 .  
         [0024]    For assembling the device, first the support  10  is inserted into the housing  25  and is fastened in a suitable pressure-proof manner. Then, the shell  23 , the electrodes  22 . 1 ,  22 . 2  and the conduit section  20  are fastened on the support  10  from the direction of the top of the housing  25 . Thereafter the bulk material can be inserted. Finally, the cap  30  is inserted into the housing  25  on the cover side. Now the open top of the housing  25  can be closed with the cover  40 .  
         [0025]    As shown in FIG. 1, the cover  40  has a circumferential flange  43 . The flange  43  rests on a radially outward oriented rim  37  of the housing  25 , with a seal  44  placed between them. A screw ring  45  is used for connecting the cover  40  with the housing  25 . An interior thread  47  of the screw ring  45  can be screwed on an exterior thread of the cover  40 . In this case the screwing-on movement is limited by a detent  46  of the screw ring  45 , which contacts the underside of the rim  37 .  
         [0026]    As FIG. 2 shows, the space between the conduit section  20  and the shell  23  is divided into four electrode chambers  21 . 1 ,  21 . 2 . An electrode  22 . 1 ,  22 . 2  is arranged in each of the electrode chambers  21 . 1 ,  21 . 2 . The division of the electrode chambers  21 . 1 ,  21 . 2  takes place by insulating bodies  50 , which are embodied as a bulkhead wall. These insulating bodies  50  are permeable to liquid media, in particular aqueous solutions. But the insulating bodies  50  are impermeable to the granules of the bulk material. On their radial ends, the insulating bodies  50  are fixed in place in seats  51  of the shell  23 , or of the conduit section  20 . The seats  51  prevent a displacement of the insulating bodies  50  and they dependably prevent an electrically conducting connection between the individual electrode chambers  21 . 1 ,  21 . 2 .  
         [0027]    During operation, water to be treated is fed to the device shown in FIGS. 1 and 2 via the inner chamber  42  of the cover  40 . The water then flows through the conduit section  36  to the conduit section  20 . In this case the water flows in the radial direction through the shell  23  of the conduit section  20 . Thereafter, the water reaches the electrode chamber  21 . 1 ,  21 . 2 . Each of the adjacently located electrode chambers  21 . 1 ,  21 . 2  is differently polarized. Accordingly, the electrodes  22 . 1  can be positively charged, the electrodes  22 . 2  can be negatively charged. A calcite precipitation out of the water to be treated then occurs in the area of the negatively charged electrode chambers  21 . 2 . In the process, the calcite is deposited on the individual carbon particles of the bulk material. A change in polarization occurs after a defined period of time. The electrodes  22 . 1  are negatively polarized, the electrodes  22 . 2  positively. Because of the polarization reversal, the calcite deposits at the carbon particles are removed and are floated out like germs. The treated water leaves the electrode chambers  21 . 1 ,  21 . 2  through the shell  23  in the radial direction. There, it flows to the conduit area  24  and can then be fed into a water main network via the outer chamber  41  of the cover  40 . The above described flow direction can be reversed, so that the water to be treated is first supplied to the outer chamber  41 . In that case the water leaves the device through the inner chamber  42 .  
         [0028]    In the embodiment of this invention as shown in FIGS. 1 and 2, the flow passes parallel through the electrode chambers  21 . 1 ,  21 . 2 . It is possible to provide a series connection of the electrode chambers  21 . 1 ,  21 . 2 . Such an arrangement is shown in FIG. 3. Here, a ring-shaped insulating body  50 , which is arranged concentrically in relation to the conduit section  20  and the shell  23 , is used in place of the radially arranged insulating bodies  50 . Two electrode chambers  21 . 1 ,  21 . 2 , which are embodied in a ring shape, are thus formed. Respectively four electrodes  22 . 1 ,  22 . 2  are arranged in the individual electrode chambers  21 . 1 ,  21 . 2 . The same as in the embodiment shown in FIG. 1, the individual electrodes are again arranged offset by 90° from each other. Based on this arrangement of the electrodes  22 . 1 ,  22 . 2 , an optimal and even flow density is achieved within the individual electrode chambers  21 . 1  and  21 . 2 .  
         [0029]    In the embodiment shown in FIG. 3, the water to be treated flows in through the conduit section  20  and arrives radially through the shell  23  of the conduit section  20  into the first electrode chamber  21 . 2 . Then the water flows through the liquid-permeable insulating body  50  and reaches the second electrode chamber  21 . 1 . From here the water reaches the conduit area  24  through the shell  23  the same way as in the embodiment in accordance with FIGS. 1 and 2.  
         [0030]    Basically, the device in accordance with FIG. 3 is identical to the device in accordance with FIGS. 1 and 2. There is only a different arrangement of the electrodes  22 . 1 ,  22 . 2  and of the electrode chambers  21 . 1 ,  21 . 2 .  
         [0031]    Initially, the electrodes  22 . 2  can be negatively polarized in the electrode chamber  21 . 1 . Accordingly a calcite precipitation occurs in the bulk material kept in the electrode chamber  21 . 1 . The water then flows through the second electrode chamber  21 . 1  and flows off via the shell  23 . A polarization change occurs after a defined period of time. The electrodes  22 . 2  then are positively polarized, the electrodes  22 . 1  negatively. Now the calcite precipitation occurs in the bulk material of the electrode chamber  21 . 1 . During this state of the polarization, the calcite deposited on the carbon particles of the bulk material in the electrode chamber  31 . 2  is removed and flushed out with the water to be treated. A change in polarization again takes place after a defined length of time.  
         [0032]    In accordance with this invention, a polarization change of more than 30 seconds provides good efficiency. If a shorter period of time is used, the effectiveness is reduced and with it the efficiency of the device.  
         [0033]    Thus, it may be advantageous to employ an electronic switching device for controlling the polarization-reversing process. In this case the individual flow-through times should be added when the water removal occurs in a clocked manner. A polarization reversal then occurs only after the preset total interval length.  
         [0034]    A flow meter can be used for optimizing the operation. The flow meter determines the amount of water which flows through and is to be treated continuously or at time intervals. The treatment current strength is then regulated as a function of this determined value. A flow meter can also be used alternatively or in addition as an indicator of the time for maintenance. A signal is emitted as soon as a defined amount of water is registered, which indicates the need for replacing the granular bulk material.  
         [0035]    For being able to make determinations regarding the wear state, it is possible to integrate a measuring apparatus in the device, which measures the conductivity of the granular bulk material.  
         [0036]    In another embodiment of the device of this invention, two or more groups of electrodes ( 22 . 1 ,  22 . 2 ) are formed. Initially, only one of the groups is operated until it is no longer sufficiently functional because of aging and/or output. Then a switch is made to a second group, or the latter is hooked up.