Abstract:
The invention relates to an evaporator device with a receptacle for holding material to be evaporated. With this evaporator device an oil film can be applied onto specific sites of a sheet to be coated, this sheet being coated with aluminum or zinc in a further step. At the sites at which the oil film is located, no aluminum or zinc is deposited. With the aid of a rod valve, precise application of the oil onto the sheet is ensured. This rod valve is driven by a stepping motor, which can release percentage fractions of oil vapor.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     This application claims priority from European Patent Application No. 050 23 355 filed Oct. 26, 2005, incorporated herein by reference in its entirety. 
     The invention relates to an evaporation device. 
     Oil evaporators are for example required for producing capacitors. Herein dielectrics, for example synthetic sheets, are provided with a metal layer. To avoid negative consequences for the capacitor following electric sparkovers, metal-free strips are provided on the synthetic sheet. These metal-free strips are generated thereby that at specific sites an oil film is applied onto the synthetic sheet. The metal vapor, preferably aluminum, subsequently applied onto the synthetic sheet, cannot become attached in place at those sites at which the oil film is located. 
     An evaporator device with a nozzle is disclosed in JP 10008241. In this document the material to be evaporated is evaporated in a crucible, wherein it escapes via a nozzle and migrates in the direction toward the substrate where it lastly condenses. By means of a valve the quantity of the escaping vapor can be controlled. However, this device is solely employed for evaporating metals. 
     A device for producing metal-free strips in sheet webs coated under vacuum, in particular for capacitors, is furthermore known, which comprises a tubular receptacle for accepting a separating agent, for example of oil (DE 39 22 187 A1). In the tubular receptacle closed by circular disk-shaped end parts, is located a heating rod, all around of which flows oil. In the receptacle is furthermore located a vapor outlet tube, one end of which projects above the oil level and at whose other end is provided an outlet nozzle. The outlet nozzle is herein located beneath the oil reservoir. 
     A device for evaporating oil is furthermore known, with the oil being disposed in a tube-like vessel (JP 2001 279425). This vessel has several openings arranged in a row, from which the vapor can escape. 
     In another device the oil is located in an elongated tank (JP 2004-214185). This tank has several openings which are arranged in a row and which assume the form of a nozzle bar. By means of this nozzle bar it is possible to coat very large areas. 
     A vaporisation device is known comprising a container as well as a seal-off device and a jet body (DE 198 48 177 A1). With this device the container is connected to the seal-off device and the seal-off device is connected to the jet body via a supply line. 
     A method for localized application of a parting means with a vaporizer onto moving substrates is also known (EP 1 493 836). This vaporizer comprises two chambers arranged one above the other and connected via a channel. The material to be vaporized is disposed in the lower chamber and can pass in the upper chamber through the channel. By means of a voltage controlled proportional valve the quantity of vapor passing in the upper chamber per time unit can be controlled. 
     The present invention addresses the problem of providing an evaporator device for the evaporation of oil, which comprises a seal-off device on the nozzle. 
     The problem is resolved according to the present invention. 
     The invention consequently relates to an evaporator device with a receptacle for holding material to be evaporated. With this evaporator device an oil film can be applied onto specific sites of a sheet to be coated, wherein this sheet is coated in a further step with aluminum or zinc. At those sites at which the oil film is disposed, no aluminum or zinc is deposited. With the aid of a rod valve precise application of the oil onto the sheet is ensured. This rod valve is driven by a stepping motor, which can release oil vapor in percentage fractions. 
     With this evaporator device substrates, preferably metallized synthetic films, can be coated with a solid or liquid mixture of saturated or unsaturated hydrocarbons. However, the use of fully synthetic oils is also possible. Therein a synthetic sheet, as shown in JP 2004-214185, can be guided by means of rollers over the evaporator device described here. 
     With this evaporator device the metal layer or the layers on the synthetic sheet are uniformly coated, since it is possible to meter the oil vapor. Subsequent coating of the oil layer with further materials utilizing this evaporator device also does not present any problems. 
     Thereby that beneath the outlet nozzle a seal-off device is disposed, the quantity of escaping oil vapor can be regulated. It is ensured that oil vapor does not continuously escape from the unit, especially since the seal-off device can also be closed completely. Therewith the escape of oil vapor is no longer possible. This has in particular the advantage that the heating process does not need to be interrupted, if, for a short time, no substrate is moved over the evaporator device. 
     A further advantage lies therein that the pollution through escaping oil vapor is reduced to a minimum. 
     The loss of oil through continuous evaporation is therewith considerably decreased. 
     An embodiment example of the invention is depicted in the drawing and will be described in the following in further detail. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a perspective exploded view of an evaporator device; 
         FIG. 2  is a cross section through the evaporator device according to  FIG. 1 ; 
         FIG. 3  is a longitudinal section through a portion of the evaporator device according to  FIG. 1 ; 
         FIG. 4  is a top view onto the evaporator device according to  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an exploded view of an evaporator device  1  according to the invention. This evaporator device  1  comprises an oil receptacle  2 , in which is located a heating rod  3 . Above the oil receptacle  2  is provided a valve plate  4  with three longitudinal bores  5 ,  6 ,  7 . In the longitudinal bores  5  and  7  are located heating rods  8 ,  9 , while in the longitudinal bore  6  is located a rod valve  10 . The heating rods  8 ,  9  or the rod valve  10  are shown in  FIG. 1  outside of the valve plate  4 . Above the valve plate  4  is located a nozzle plate  11 , on which rests a fine adjustment plate  12 . By  14  is denoted a stepping motor, which drives a first wheel  15 , which, via a coupling element  16 , for example a chain or a V-belt, drives a second wheel  17 . The preferred embodiment here is a chain. With this second wheel  17  is connected the one end of rod valve  10  which is rotatable about its longitudinal axis with the aid of the stepping motor  14 . 
     On the top side of oil receptacle  2  are located several openings, through which the oil vapor can escape from the oil receptacle  2 . These openings are not visible in  FIG. 1 , only the seals  18  to  25  encompassing them. In the rod valve  10  several throughbores  26  to  34  are provided, whose number corresponds to the number of seals  18  to  25 . On the not visible opposite side the rod valve  10  also has throughbores, provided it is a hollow tube. If it is solid, the throughbores  26  to  34  extend through the entire rod valve  10 . 
     The same number of bores  35  to  47  are found above the longitudinal bore  6  in the valve plate  4 . A corresponding number of bores is also provided beneath the longitudinal bore  6 . However, these bores are not visible in  FIG. 1 . 
     If the oil in the oil receptacle  2  is heated by means of the heating rod  3 , is arrives through the openings in oil receptacle through the openings, not shown in  FIG. 1 , on the underside of the valve plate  4  on the rod valve  10  located in the longitudinal bore  6 . If the throughbores  26  to  34  of the rod valve  10  are oriented vertically, evaporated material can escape through the rod valve  10  and the corresponding bores  35  to  47  through a gap formed by the fine-adjustment plate  12  and the nozzle plate  11  and be deposited on a substrate above this gap. 
     By  48  to  54  connecting bolts are denoted, with which the individual parts of the evaporator device  1  are held together. 
       FIG. 2  shows a cross section through the evaporator device  1 . In the interior space  55  of the oil receptacle  2  is located a heating rod  3 , which is comprised of a core  56  and a casing  57 . This core  56  can be heated by means of a voltage source. The heating rod  3  is completely encompassed by oil  58 . The oil receptacle  2  has several openings on its top side, of which one opening  59  is visible. Above this opening  59  is located one of the annular seals  18  to  25 , for example seal  22 . Adjoining the opening  59  is a bore  60  in valve plate  4 , which, in turn, leads to the bore  30  in rod valve  10 . Above this rod valve is located an interspace  61 , which has an upper gap opening  62 . This gap opening  62  is formed by the nozzle plate  11  and the fine-adjustment plate  12 . Between nozzle plate  11  and valve plate  4  is provided a seal  63 , which, as evident in  FIG. 1 , is placed about the entire interspace  61 . In the longitudinal bores  5 ,  7  can again be seen the heating rods  8 ,  9 . These heating rods  8 ,  9  heat the valve plate  4  to a temperature, at which condensation of the oil in the valve plate  4  is impossible. 
     In the view of  FIG. 2  the rod valve  10  is open, i.e. the evaporated material can pass through the gap opening  62  and reach a, not shown, substrate, which is located above this gap opening  62 . 
     By rotating the rod valve  10  in the clockwise or counterclockwise direction, the material vapor issuing from the oil receptacle  2  can be more or less throttled. Starting at a specific angle, however at the latest after a rotation by 90 degrees, the material vapor is sealed off completely through the rod valve  10 . 
       FIG. 3  depicts a portion of the evaporator device  1  shown in  FIG. 1 , and specifically with the rod valve  10  closed. Herein again the oil receptacle  2  with the heating rod  3  is evident. The throughbores  32  to  34 ,  82  to  84  in the rod valve  10  extend herein into the plane of drawing, such that the openings  60 ,  68  to  71  on the underside of the valve plate  4  are closed. Consequently no oil vapor can arrive from the oil receptacle  2  via the holes  59 ,  78  to  81 ,  85  or  60 ,  68  to  71  in the interspace  61  and from there reach the substrate. About the openings  60 ,  68  to  71  ring seals  22 ,  72  to  75  are disposed. Furthermore, a set screw  76  can be seen. Via this set screw  76 , which for example may be a headless screw, the wheel  17  is fastened on the axle of the rod valve  10 . It is moreover evident that the oil receptacle  2  is closed off by a plate  77 . 
     Furthermore is visible in  FIG. 3  the wheel  17 , on which the preferred embodiment of the coupling element  16 , the chain, can be emplaced. 
       FIG. 4  shows a partially broken open top view onto the evaporator device  1  according to  FIG. 1 . Herein again the nozzle plate  11  with the fine-adjustment plate  12  can be seen as well as the heating rods  8 ,  9  and the rod valve  10 . The wheels  15  and  17 , the V-belt  16  and the stepping motor  14  are evident. 
     The fine-adjustment plate  12  has several elongated holes  90  to  95 , through which machine screws  96  to  101  are guided. It becomes hereby possible to displace the fine-adjustment plate  12  such that a gap formed between it and the nozzle plate  11  becomes greater or smaller. Through this gap  102  the vapor can subsequently leave space  61 . Below this space  61  the openings  27  to  34  of rod valve  10  are visible. 
     The stepping motor  14  is fastened with a bolt  103  on a U-shaped metal sheet plate  104 , this sheet plate  104 , in turn, being connected by means of machine screws  105 ,  106  with the valve plate  4  not visible in  FIG. 4 .