Abstract:
The invention relates to a liquid coating device ( 10 ) comprising a rotor housing ( 12 ) accommodating one or more spray rotors ( 22 ). The spray rotors ( 22 ) comprise a drive device ( 46 ), a drive shaft ( 42 ), a bearing element ( 50 ) and a spray disk ( 38 ). The spray disk ( 38 ) is arranged above the bearing element ( 50 ). According to the invention, maintenance and lifespan of the liquid coating device ( 10 ) are improved significantly.

Description:
BACKGROUND OF THE INVENTION 
     The invention concerns a liquid coating device for applying liquid to moving surfaces, with a rotor housing comprising at least one or more spray rotors, each spray rotor comprising a drive means, a drive shaft projecting from the drive means, a bearing element for the drive shaft and a spray disk driven by the drive shaft, wherein the spray disk is substantially formed like a pan and has an upwardly facing opening. 
     DE-A-20 58 667 discloses a device for applying liquid onto moving surfaces which comprises a rotor housing containing a plurality of spray disks. These spray disks each have a vertical axis of rotation, wherein the axes of rotation terminate at their upper ends in a V-belt pulley. This V-belt pulley is driven via one single V-belt. A bearing box is located below this drive which bears the entire rotation unit on the rotor housing. The pan-shaped spray disk which is open at the top and into which the liquid to be sprayed is introduced via a line, is located below this bearing box. 
     It has turned out that cleaning of the overall spray device is relatively complicated since dismantling of the spray disk requires dismantling of the belt pulley and of the entire bearing. The bearing is moreover located in the spray region of the liquid to be sprayed which can reduce the service life of the bearing elements. 
     It is therefore the underlying purpose of the present invention to provide a liquid coating device of the above-mentioned type with which cleaning of the spray disk and of the entire spray region is considerably facilitated and which has a longer service life. 
     SUMMARY OF THE INVENTION 
     This object is achieved in accordance with the invention with a liquid coating device of the above-mentioned type in that, in the predominant position of use of the device, the spray disk is disposed substantially above the drive means. 
     In another solution, the opening of the spray disk faces away from the drive means. 
     In yet another solution, the rotor housing comprises a separating wall which separates the bearing element from the spray disk. 
     The above-mentioned variants of the inventive application device considerably facilitate cleaning of the spray disk and of the entire spray region, since the spray disk is disposed above the drive means and can be accessed from the top. Only the lid of the rotor housing must be removed to provide access to the spray disks from above. Dismantling of the entire drive, in particular of the belt pulley, is no longer required since it is located below the spray disk. The easily accessible spray disks can be cleaned and also exchanged e.g. by removing them from the drive shaft. 
     The bearings are protected since the opening of the spray disk faces away from the drive means. The liquid is thrown from the spray disk substantially outwardly and upwardly, and therefore the bearing or its annular clearance is no longer in the direct flow or spray region of the liquid to be sprayed. 
     Finally, the third embodiment of the invention has the advantage that the region where the spray disk is located and where the liquid is sprayed and whirled, is separated by a separating wall from the bearing element. For this reason, the bearing element and therefore the entire drive unit are separated from the spray disk (located in a separate space). This embodiment is particularly advantageous when aggressive liquids are used since they are prevented from reaching the bearing and drive parts. 
     In a further development, the spray disk is mounted on the drive shaft. This has the substantial advantage that the spray disk can be replaced by a new or a different spray disk in a relatively easy fashion such that when e.g. the spray disk is soiled, it can be removed and a new spray disk can be mounted on the drive shaft. Exchange of spray disks moreover permits relatively easy adjustment to the liquid to be sprayed or to the amount of liquid. 
     To ensure safe connection between the spray disk and drive shaft, rotary carriers are provided which are disposed on the drive shaft or on the spray disk and are adapted to the respective other component. These rotary carriers ensure easy coupling between the spray disk and the drive shaft and also slip-free rotational carrying along of the spray disk. 
     In order to avoid intercepting the liquid sprayed in the spraying direction, the rotor housing has a liquid tub extending above the drive means and below the spray disk. This tub is advantageously formed as separating wall and prevents liquid, spray or the like from passing directly from the region of the spray disk to the drive region accommodating the bearing. The liquid tub which collects the liquid not sprayed, divides the rotor housing into a dry drive region and a moist spray region. 
     Advantageously, a liquid supply is provided from above and feeds onto the spray disk. This liquid supply is located exclusively within the region where the spray disks are provided and the liquid line does not have to be guided through a separating wall or a liquid tub. 
     In one embodiment, the liquid is advantageously supplied centrally on the spray disk. This is substantially advantageous in that the liquid which is supplied exactly at the center, is uniformly distributed on the spray disk. 
     In a preferred embodiment, the bearing element has an inner ring connected to the rotor housing and an outer ring connected to the drive shaft. The inner ring and the outer ring are thereby parts of a roller or sliding bearing. The inner ring is preferably connected to the liquid tub of the rotor housing via a sleeve. Via this sleeve, the inner ring is rigidly clamped to the liquid tub or the separating wall of the rotor housing, whereas the outer ring seats in a corresponding receiving bore of the drive means. The drive belts engage the outside, i.e. the periphery, of this drive means and the drive means is provided with the central drive shaft which is guided without contact through the sleeve to drive the spray disk. 
     The sleeve preferably has a cover which overlaps and covers the upper side of the inner ring and outer ring of the bearing. This prevents e.g. condensed liquid from dripping into the bearing from above. 
     In accordance with one preferred embodiment, the lower end of the sleeve and/or the drive means may be provided with a liquid outlet such that the liquid entering the sleeve can be easily drained from the bottom. A further liquid outlet is also provided at which the edge of the cover terminates. This liquid outlet may be provided within the bearing element to prevent liquid dripping from the cover from being guided past the bearing element and onto the belt pulley. The overall bearing element may be provided with a labyrinth for leaking liquid. This labyrinth prevents liquid from entering the bearing and ensures that the liquid is quickly guided out of the bearing element. 
     In a further development, the spray disk has a downwardly extending apron on its lower side which is immersed into a liquid bath of a liquid tub. The apron immersed into the liquid bath serves as a vapor lock, preventing liquid vapor from entering the bearing element via the sleeve. 
    
    
     Further advantages, features and details of the invention can be extracted from the following description which describes in detail a particularly preferred embodiment with reference to the drawing. The features shown in the drawing and mentioned in the description and claims may be essential to the invention individually or collectively in arbitrary combination. In particular, the three different solutions may be combined. The drawing shows a section through the inventive liquid coating device. 
     BRIEF DESCRIPTION OF THE DRAWING 
     The sole FIGURE shows a cross section of the liquid coating device in accordance with the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a cross-section through a liquid coating device, referred to in its totality with  10 , which is e.g. used in printing machines to moisten paper webs. These devices are also used in the textile industry to spray liquid onto fabric sheets. The liquid coating device  10  has a rotor housing  12  which consists generally of sheet metal and has an upper part  14  and a lower part  16 . The lower part  16  is substantially formed as collecting tub and has an outlet  18  through which the collected liquid can drain. The upper part  14  has a separating wall  20  to which a plurality of spray rotors  22  are mounted. The upper part  14  also has an outlet  24  which feeds into the outlet  18 . The separating wall  20  is also formed as liquid tub  26  with one side wall of that liquid tub  26  being formed by a slider strip  28 . The slider strip  28  adjusts the size of a diaphragm opening through which the liquid is sprayed from the liquid coating device  10 . Another liquid supply  30  is located within the upper part  14  and is fed by a supply line  32 . FIG. 1 clearly shows that the wall  20  separates the inner space of the upper part  14 , which contains liquid, from a space which is located below the separating wall  20  and contains no liquid. The separating wall  20  separates a spray region  34  from a drive region  36 . 
     The spray region  34  has a spray disk  38  which is mounted to a coupling element  40  at the upper end of a drive shaft  42 . This is effected either with a set screw  44  or a rotary carrier which are either provided on the coupling element  40  or on the drive shaft  42 . In any event, the spray disk  38  can be easily mounted and fastened to the upper end of the drive shaft  42  via the coupling element  40 . The spray disk  38  is provided centrally with liquid via the liquid supply  30 . The liquid is disposed in the center of the spray disk  38  so that it can be evenly distributed. 
     The drive shaft  42  is pressed into a drive means  46  which is located below the separating wall  20  and therefore within the drive region  36 . The drive means  46  has a central bore  48  into which two roller bearings  50  are pressed. The outer rings  52  of the roller bearings  50  are rigidly connected to the drive means  46 . The inner rings  54  of the roller bearings  50  are disposed on a sleeve  56  for secure mutual rotation therewith, wherein the sleeve penetrates the separating wall  20  from below via a bore. The upper end of the sleeve  56  is provided with an outer thread and bears a nut  58 . A cover  60  and a seal  62  are disposed on the sleeve. Tensioning of the nut  58  rigidly connects, via the sleeve  56 , the inner rings  54 , the cover  60  and seal  62  to the separating wall  20  and therefore to the rotor housing  12 . 
     The edge  64  of the cover  60  is downwardly angled and feeds a liquid outlet  66  in the drive means  46 . The cover  60  covers the upper side of the roller bearings  50  to prevent liquid from getting into the roller bearings  50  from above. 
     The drive shaft  42  penetrates through the sleeve  56  with play and the drive means  46  is provided with additional liquid outlets  68  below the roller bearings  50  with which the free space between the sleeve  56  and the drive shaft  42  communicates. Liquid penetrating into the sleeve  56  can exit the drive means  46  through these liquid outlets  68 . 
     The circumference of the drive means  46  is provided with two peripheral grooves  70  in which the drive belts  72  are disposed. The spray rotor shown in the drawing is thereby driven via one drive belt by a neighboring spray rotor and drives the other neighboring spray rotor via the other drive belt. To provide for an equilibrium of moments, four peripheral grooves may be provided wherein an outer belt pair is coupled after each inner belt pair. Since the spray rotors  22  have identical mutual lateral separations, the drive belts  72  have identical lengths. The drive belts  72  surround only two spray rotors  22  and are therefore not mutually subjected to bending strain which increases their service life. 
     The lower side of the coupling element  40  has a peripheral apron  74  whose lower end is located in the region of the bottom of the liquid tub  26 . When the liquid tub  26  is filled with liquid, the lower edge of the apron  74  is immersed into this liquid thereby forming a barrier which prevents even the finest of liquid drops from getting into the drive means  46  via the sleeve  56 . The apron  74  therefore generates a vapor lock. 
     The drawing clearly shows that a lid  78  can be removed from the upper part  14  after releasing the mounting screw  76 . The spray rotors  22 , in particular the spray disk  38  can then be accessed from the top. The entire spray region  45  can also be cleaned. 
     The inventive liquid coating device  10  can be operated not only in the orientation shown in the drawing. The device  10  may be inclined at an angle so the the objects to be sprayed can also be sprayed from the top or from below. This angle may be up to 90°.