Abstract:
The invention relates to a device for filling a tank with a liquid medium, in particular a urea solution, comprising a filling pipe and comprising a suction channel for removing air from the tank. The invention is characterized in that at least one air guiding element is provided inside the suction channel, said air guiding element being designed to deflect the air transversely to the longitudinal axis of the filling pipe.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a device for filling a tank with a liquid medium, in particular a urea solution, comprising a filling pipe and a suction channel for removing gas or respectively air from the tank. Furthermore, the invention relates to a device for filling a tank with a liquid medium, in particular a urea solution, with a filling pipe and a check valve element, which is attached to the end of the filling pipe. Finally, the invention relates to a filling system for a liquid medium, in particular a urea solution, with a device according to the invention for filling a tank with a liquid medium and a holding device for receiving the device for filling. 
         [0003]    2. Description of Related Art 
         [0004]    Aqueous urea solutions (for example, known under the brand name “AdBlue”) are increasingly being used for exhaust gas treatment for commercial vehicles, in particular trucks and omnibuses. Urea solutions are also now being increasingly used in passenger vehicles, wherein the urea solutions are stored in auxiliary tanks in the vehicle. The filling either takes place via commercially available canisters or—like fuel—at specially provided urea pumps. The delivery of urea solutions via special pumps will increase greatly in the future since this is more environmentally sound and cost-effective. Due to the chemical properties of urea solutions, tank systems must meet special requirements so that the filling systems known from the fuel field cannot be readily used. 
         [0005]    This is due in particular to the fact that urea solutions crystallize and the crystals can lead to malfunctions. For this reason, the tank systems should be designed so that urea solutions cannot get to areas outside the filling pipe. Moreover, the filling should be able to take place easily and quickly. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Thus, the object of the present invention is, among other things, to design the initially named device for filling a tank with a urea solution such that contamination of the device and the vehicle is avoided. 
         [0007]    This object is solved in the case of the device for filling a tank with a urea solution in that at least one air guiding element is provided inside the suction channel, said air guiding element being designed to deflect the air transversely to the longitudinal axis of the filling pipe. 
         [0008]    In the previous solutions, the air (gas) suctioned out of the tank is normally suctioned more or less parallel to the filling pipe so that liquid components of the urea solution contained in the suctioned air can get into the entire suction channel area. Since the cleaning of areas of the suction channel that lie remote from the suction opening is more difficult, urea crystals can form there, which can lead to malfunctions. 
         [0009]    Due to the fact that, in the case of the device according to the invention, the air flows transversely to the longitudinal axis of the filling pipe, i.e. either at a right angle or diagonal to the longitudinal axis, the flow path of the suctioned air is first extended so that liquid components rather remain in an area close to the suction opening. Since these front areas are easier to clean, the risk of malfunctions due to urea crystals can be reduced. 
         [0010]    Preferably, the suction channel is delimited to the inside by the filling pipe and to the outside by a wall element surrounding the filling pipe at least partially. If the air guiding element is designed so that it extends around the filling pipe in a coil-like manner, the suctioned air is added to a circular or respectively coil-like path with the result that the liquid components are precipitated on the outer-lying wall element due to centrifugal force. In this manner, a large portion of the liquid components of the suctioned air can already be precipitated in the front area of the device for filling (hereinafter referred to as filling device). On one hand, these precipitated components can simply flow back into the tank or respectively out of the filling device so that their crystallization inside the filling device is avoided. On the other hand, these precipitations in the front area of the filling device can be easily removed through cleaning 
         [0011]    In a preferred further embodiment, the wall element is designed as a bushing, which extends at least over the length of the at least one air guiding element. The air guiding element is preferably provided on a support element on its side facing the filling pipe, wherein the support element has a passage for the filling pipe. The air guiding element and the support element are also preferably designed from a single piece of material resistant to the liquid medium, preferably stainless steel or a plastic material. 
         [0012]    These measures have proven to be particularly advantageous with respect to production. The support element can be easily pushed over the filling pipe and supports the air guiding element extending outward radially and progressing in a coil-like manner. The wall element delimiting the suction channel to the outside is designed as a tubular bushing, which in turn can be very easily pushed over the filling pipe and the support element with the air guiding element. 
         [0013]    Thus, not only are the production costs of the individual parts low, but also the measures required for assembly. Furthermore, these components can also be replaced easily. 
         [0014]    In a preferred further embodiment, the air guiding element has first sections that run at a right angle to the longitudinal axis of the filling pipe. It is furthermore preferred if the air guiding element has second sections, which run diagonally to the longitudinal axis of the filling pipe, wherein first and second sections alternate and two first sections are interconnected via a second section. It is furthermore preferred if two subsequent first sections are offset in the longitudinal direction and are arranged offset in the circumferential direction of the filling pipe by 180°. 
         [0015]    This embodiment of the air guiding element delivers, on one hand, the coil-like flow path of the suctioned air and enables, on the other hand, a very beneficial production with little tool-based effort compared to a “real” coil-like progression. 
         [0016]    In a preferred further embodiment, a check valve element is provided on the outlet end of the filling pipe. 
         [0017]    The purpose of this check valve element is to seal the outlet end of the filling pipe if the urea solution is not delivered to the tank with a specified pressure. Since the check valve element is attached to the outlet end of the filling pipe, there is no or respectively minimal dripping of the urea solution after removing the filling device from the tank. 
         [0018]    In a preferred further embodiment, the check valve element has a tubular housing with a first and a second longitudinal section, wherein the first longitudinal section has a smaller inner diameter than the second longitudinal section and has a conical diffusor, which is provided inside the second longitudinal section coaxially to it and faces the first longitudinal section with its diameter-larger end, wherein the diffusor supports a sphere in a spring-loaded manner such that the sphere can close and release the end of the first longitudinal section. Particularly preferably, the tubular housing has a third longitudinal section, which has a tapering inner diameter for forming a nozzle. 
         [0019]    These measures ensure that the urea solution exits the outlet end in the most laminar manner possible. This laminar flow is achieved despite the fact that the urea solution must flow around the provided sphere of the check valve on the end of the filling pipe. The improvement in the flow is achieved through the conical diffusor, which ensures an expanding annular space between the tubular housing and diffusor, as seen in the longitudinal direction. 
         [0020]    A laminar flow prevents foam or droplet formation and a backup in the area of the outlet end so that, as a result, the “danger” of an early and undesired shutdown is reduced. 
         [0021]    The flow can be preferably further improved in that a aerator (e.g. in the form of a mixing jet) is provided on the outlet end, i.e. as seen in the direction of flow, after the check valve. 
         [0022]    A spill-over and/or a spraying back of the liquid medium (so-called “spitback”) can thus be prevented. 
         [0023]    Particularly preferably, the filling device is designed as a pump nozzle. 
         [0024]    The handling and operating of the filling device is thus considerably simplified. 
         [0025]    The object underlying the invention is also solved by a device for filling a tank with a liquid medium, in particular a urea solution, which has a filling pipe and the previously explained check valve element. 
         [0026]    In other words, this means that the two characteristics of the suction channel with air guiding element and the check valve element can be used alone or in combination in a device for filling a tank in order to solve the object according to the invention. This also means that the preferred further embodiments described above can be used for both variants. 
         [0027]    The object underlying the invention is also solved by a filling system for a liquid medium, in particular a urea solution, which has a filling device according to the invention for receiving the device for filling and a cleaning device, which is designed to clean the suction channel. 
         [0028]    The cleaning device preferably generates an air flow for the cleaning 
         [0029]    Particularly preferably, the cleaning device is connected with the end of the suction channel opposite the suction opening, wherein the cleaning device blows air into the suction channel, which flows through the suction channel to the suction opening. Naturally, the cleaning device can also suction air through the suction channel, for example up to the suction opening, in order to effectuate a cleaning. 
         [0030]    Through the cleaning, liquid components present in the suction channel are blown and/or suctioned to the outlet end. 
         [0031]    It is understood that the characteristics mentioned above and still to be explained below can be used not only in the respectively specified combination but also in other combinations or alone, without leaving the framework of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0032]    Additional advantages and embodiments of the invention result from the description and the accompanying drawings. The drawings show in: 
           [0033]      FIG. 1  a perspective representation of a filling device according to the invention; 
           [0034]      FIG. 2   a, b  a cross-sectional view of the filling device as well as an enlarged section from this view; 
           [0035]      FIG. 3  an exploded view of the filling device according to the invention with a few removed structural elements; 
           [0036]      FIG. 4  an exploded view of the filling device from the other side with a few removed structural elements; 
           [0037]      FIG. 5   a, b  a sectional representation of a check valve element according to the invention in cross-section as well as in an exploded representation; 
           [0038]      FIG. 6   a, b  a cross-sectional view of an alternative check valve element as well as an exploded representation of this check valve element; 
           [0039]      FIG. 7  a schematic representation of a filling system according to the invention and 
           [0040]      FIG. 8  a characteristic line of the delivery rate over time to explain the control behavior. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0041]      FIG. 1  shows a perspective view of a filling device with reference number  10 . This filling device is preferably designed in the form of a pump nozzle  11 . The filling device  10  serves to fill a vehicle, for example a passenger vehicle or a truck, with a liquid medium, in particular a urea solution (also known as “AdBlue”). The filling device is thereby designed to enable a closed filling. Such urea solutions are now very frequently used in the field of exhaust gas treatment, in particular to convert the nitrogen oxides into nitrogen and water vapor. Hereinafter, only a urea solution is mentioned as the liquid medium, although the described embodiments can also be used advantageously for other liquid mediums. 
         [0042]    The filling device  10  has a handle area  12  and a connection area  14  connecting to it. 
         [0043]    The handle area  12 , which is preferably composed of two handle shells  16 ,  18  made of plastic, is with respect to its shape similar to the conventional shape of a pump nozzle of a tank system for gas, diesel, etc. On its end of the handle area  12  lying opposite the connection area  14 , a medium hose  20  is connected or can respectively be connected, which feeds a urea solution on one hand and removes gas or respectively air (hereinafter, only “air” is referenced for simplification reasons) from the tank during filling on the other hand. 
         [0044]    A cylindrical operating element  22 , which is held in a rotatable manner around its longitudinal axis, is provided in the connection area  14 . The operating element  22  serves to screw the filling device  10  with a connection piece (not shown) to a vehicle tank in order to enable a closed filling. 
         [0045]    The operating element  22  has two longitudinal sections with different diameters, wherein the longitudinal section  24 . 1  that can be handled by the user has a greater diameter than the second longitudinal section  24 . 2  connected to it. The two longitudinal sections  24 . 1  and  24 . 2  of the operating element  22  are preferably provided from two separate components, which are interconnected for example via screws. 
         [0046]      FIG. 1  shows an internal-thread element  26 , which is provided coaxially to the second longitudinal section  24 . 2 . This internal-thread element fits on the connection piece of a tank of a vehicle. 
         [0047]    The connection between the internal-thread element  26  and the operating element  22 , here in particular the second longitudinal section  24 . 2 , is preferably not permanent, but rather provided in the form of a ratchet connection. This means that the operating element  14  during connection with the tank fitting continues to turn the internal-thread element until a specific torque is reached. The connection between the internal-thread element and the operating element  14  is then released so that the latter “turns”, without exerting further torque on the internal-thread element. The more exact structure of this ratchet connection will be explained later. 
         [0048]    Finally,  FIG. 1  also shows a filling pipe  28 , which preferably extends coaxially to the operating element  14  and from the second longitudinal section  24 . 2 . Instead of a coaxial arrangement, both elements could e.g. also be arranged eccentrically to each other. A check valve element  30  is provided on the end of the filling pipe  28 , wherein the check valve element  30  has an outlet opening  32  for the urea solution. The outlet opening  32  is thus located at a predetermined distance from the internal-thread element  26  so that the filling pipe  28  protrudes into it during connection with the connection piece of a vehicle. Furthermore, a aerator is provided downstream from the check valve element  30  on the outlet opening  32 , which upgrades or respectively conditions the outflow. 
         [0049]    As already mentioned, air is removed from the tank during filling with the urea solution. During filling, the air thereby escapes and/or is suctioned away in a pendulum process. This removal of air takes place through an annular space  34 , which is formed between the internal-thread element  26  and the filling pipe  28  or respectively occurs in the screwed-on state between the inner surface of the connection piece and the outside of the filling pipe  28 . The filling pipe  28  itself serves solely to guide the urea solution. 
         [0050]    The inner structure of the filling device  10  is explained in detail below with respect to  FIGS. 2 to 4 . 
         [0051]    The filling pipe  28  is formed at least in the area of the operating element  22  up to the outlet opening  32  as pipe  36 , preferably made of stainless steel. This pipe  36  is connected with a hose  38  on its end lying opposite the outlet end  32 , which extends through the handle area  12  up to a coupling element  40  on the end of the handle area  12 . This coupling  40  serves to connect the medium hose  20 . 
         [0052]    The pipe  36  is preferably guided coaxially (eccentrically would also be possible) within the operating element  22  and is surrounded by a bushing  42  in its front longitudinal section, i.e. facing the outlet end  32 , wherein this bushing  42  is part of a housing element  44 . The bushing  42  and the housing  44  are easy to see in  FIG. 3 . The bushing  42  is designed so that the inside of the bushing  42  rests on the pipe  36 . The inner diameter of the bushing  42  thus corresponds approximately with the outer diameter of the pipe  36 . The pipe  36  is preferably coated for insulation. 
         [0053]    As can be seen in particular from  FIGS. 3 and 4 , the bushing has a preferably coil-like structure  50 , which serves as an air guiding element  52 , in a longitudinal section  46 . 
         [0054]    The housing  44  has a larger diameter than the bushing  42  so that a step  54  is formed. The surface of this step  54  extends diagonally, in particular at a right angle, to the longitudinal axis of the filling pipe  28 . The housing  44  serves, among other things, to receive a printed circuit board  56  and corresponding connection lines  58 . The printed circuit board  56  carries all electronic components required to operate the filling device, which provide in particular a sealing identification and a fill level identification and forward the corresponding signals to the filling system. 
         [0055]    A stop bushing  62 , the inner diameter of which corresponds with the outer diameter of the coil-like structure  50 , is mounted on the longitudinal section  46  of the bushing  42 . In particular, the stop bushing  62  is designed such that the coil-like structure  50  rests on the inside of the stop bushing  62 . The stop bushing  62  is stuck above a tubular fitting  64  in the area of the step  54 , wherein an O-ring  66  seals the connection, in particular from the passage of air or the urea solution. 
         [0056]    The stop bushing  62  has a flange  68  on its end facing the outlet end  32 , which is engaged behind by an annular end section of the internal-thread element  26 . 
         [0057]    The bushing  42  with the coil-like structure  50  forms an air guiding channel  70  together with the stop bushing  62  and the internal-thread element  26 , which extends up to the step  54  and the fitting  64 . From there, the channel  70  opens into an annular space  72 , which extends up to the coupling  40  on the end of the handle area  12 . There, the annular space  72  opens into a corresponding air guiding channel  74 . 
         [0058]    The coil-like structure  50  serves as an air guiding element  52  and ensures that the air from the tank does not flow straight to the step  54  and into the annular space  72 , but rather is directed in a coiled path around the filling pipe  28  and the bushing  42 . This—in the projection—circular movement of the air in the longitudinal section  46  ensures that liquid components in the suctioned air wander to the outside through the centrifugal forces and precipitate to the greatest extent possible on the stop bushing  62 . Furthermore, the air guiding channel is lengthened substantially. The geometry of this coil-like structure  50  as well as the arrangement of the transition between the air guiding channel  70  and the annular space  72  should be designed so that liquid components are precipitated before transfer of the air into the annular space  72 . These liquid components can then again run along the bushing  42  or respectively the stop bushing  62  in the direction of the outlet end  32 . 
         [0059]    This cyclone-like guidance of the suctioned air flow should prevent the liquid components, i.e. urea solution, from getting into areas downstream of the step  54 . The considerably extended air guidance and the coil-like or respectively labyrinth-like arrangement of the air guiding element also contribute to this. Blockages/malfunctions that are not easy to fix result from the crystallization of this urea solution in this area. A cleaning of just the front longitudinal section  46  of the bushing  42  is also much easier from the outside. Moreover, this part can also be replaced easily. 
         [0060]    For production reasons, the structure  50  is not designed exactly in a coil-like manner. Rather, this structure is composed of straight sections  76  and  78 , wherein the sections  76  run at a right angle to the longitudinal axis of the bushing  42  and the sections  78  diagonal to the longitudinal axis. As results from  FIG. 3  or respectively  4 , right-angle sections  76  and diagonal sections  78  alternate so that a diagonal section  78  connects two right-angle sections  76  offset in the longitudinal direction and offset in the circumferential direction by 180°. All longitudinal sections  76 ,  78  are preferably interconnected so that the coil-like structure results. 
         [0061]    As already mentioned, this coil-like structure ensures that the flow channel is elongated and the coil prevents the urea solution directly flowing or sloshing back from getting directly inside the pump nozzle. Furthermore, the escaping air flows around the bushing  42  in a coil-like manner so that liquid components in the suctioned air precipitate on the outer-lying stop bushing  62  due to centrifugal force. One advantage of this coil-like structure is that the flow path from the internal-thread element  26  to the step  54  is extended considerably so that urea solution rising or respectively sloshing back in the tank does not so quickly reach the annular space  72  lying behind the step  54 . 
         [0062]    As results from  FIGS. 3 and 4 , the internal-thread element  26  preferably has serrated recesses  82  on its border area facing away from the outlet end, the diagonally progressing flanks  84  of which—in the case of a clockwise revolution—lie in front and the perpendicular flank  86  behind. If a counter-clockwise revolution is desired, the diagonally and perpendicularly progressing flanks are arranged accordingly in the opposite manner. 
         [0063]    In the case of the turning of the operating element  22 , the internal-thread element  26  works together with a trigger element  86 , which has correspondingly designed saw teeth  88  on its end facing the internal-thread element  26 . The arrangement of these saw teeth  88  in the circumferential direction of the cylindrical trigger element  86  corresponds to the arrangement of the recesses  82  so that the saw teeth  88  can dip into the recesses  82 . 
         [0064]    The trigger element  86  has driving elements  90  on its circumferential surface, which work together with corresponding elements on the inside of the first longitudinal section  24 . 1  of the operating element  22 . A rotational movement of the operating element  22  is transferred to the trigger element  86  via these driving elements  90 . This rotational movement is transferred to the internal-thread element  26  via the diagonal flanks of the saw teeth  88  so that the internal-thread element  26  can be screwed onto the external thread of the connection piece of the tank on the vehicle. As soon as the internal-thread element  86  is tightened, the diagonal flanks of the saw teeth  88  of the trigger element  86  glide along the diagonal flanks  84  of the recesses  82  so that the entire trigger element  86  moves backwards in the longitudinal direction, i.e. away from the outlet end  32 . As soon as the saw teeth  88  have left the recesses  82 , the operating element  22  can be turned clockwise. 
         [0065]    In order to release the internal-thread element  26  from the connection piece again, the operating element can be turned counter-clockwise, wherein the perpendicular flanks of the saw teeth  88  then work together with the perpendicular flanks  86  of the recesses  82  in a form-fitting manner and can transfer the torque for the opening. 
         [0066]    The trigger element  86  has a cylindrical section  92 , which—as can be seen in  FIG. 2   b  —dips into an area  94  while it is gliding back. This area is monitored electrically/electronically, for example with the help of optical/opto-electrical elements in order to deliver a signal to the control electronics, which signals a complete sealing or respectively screwing on of the filling device. Naturally, the dipping of the cylindrical section  92  into the area  94  can be detected and captured not just optically, but for example also mechanically via mechanical switch elements. For example, magnetoresistive switches, Reed switches, Hall sensors, etc. are conceivable as switch elements. 
         [0067]    As results for example from  FIG. 2   b , the check valve element  30  is inserted, e.g. stuck or screwed, into the end of the filling pipe  28 . This check valve element serves to prevent the running of the urea solution out of the filling pipe as soon as the urea solution is no longer pumped. In other words, this means that this valve is only opened when a certain pressure is reached in the filling pipe  28 . 
         [0068]    The structure of the check valve element  30  according to a first embodiment is shown in  FIGS. 5   a  and  5   b . The check valve element  30  has a cylindrical housing  98 , which has a first longitudinal section  100 . 1  preferably with thread, a second longitudinal section  100 . 2  connecting to it and a third longitudinal section  100 . 3  connecting to it. The first longitudinal section  100 . 1  is designed so that it can be stuck or screwed into the filling pipe  28 , in particular into the inner-lying pipe  36 . The outer diameter of this first longitudinal section  100 . 1  thus corresponds with the inner diameter of the pipe  36 . The second longitudinal section  100 . 2  now has a greater outer diameter than the first longitudinal section and a greater inner diameter than the first longitudinal section  100 . 1 . 
         [0069]    The third longitudinal section  100 . 3  has a tapering outer diameter as well as a tapering inner diameter, wherein it should be noted here that the outer diameter of the second and of the third longitudinal section  102 ,  103  can also be designed differently than shown. These two longitudinal sections depend solely on the design of the inner diameter. 
         [0070]    Within the second longitudinal section  100 . 2 , a diffusor element  102  is provided, which has a conical or respectively cone-shaped outer geometry. The larger (with respect to the diameter) end  104  of the diffusor thereby faces the first longitudinal section  100 . 1 . 
         [0071]    The diffusor element  102  is attached to the inside of the housing  98  via fastening elements  112 , wherein this fastening should cover as little flow cross-section as possible. 
         [0072]    The diffusor element  102  has on its end  104  a recess  106 , which serves to receive a sphere  108  and a spring  110 . One side of the spring  110  is supported on the diffusor element  102  and the other side on the sphere  108 . The spring presses the sphere  108  against the opening of the longitudinal section  101  in order to seal this opening. In order to release the opening, i.e. to press the sphere into the diffusor element  102  against the force of the spring  110 , the urea solution must be conveyed with a certain pressure. 
         [0073]    If the sphere  108  has released the opening, the urea solution can flow into the annular space  112  around the end  104  of the diffusor element  102 . Due to the conical shape of the diffusor element  102 , the annular space  112  expands in the direction of flow, i.e. towards the outlet end  32 . The flow channel cross-section thus increases. 
         [0074]    The purpose of this geometry is to even out, i.e. to make laminar, the flow after the flowing around of the end  104  of the diffusor element. The pressure and the flow speed decrease in this area. The tapering longitudinal section  100 . 3 , which works like a nozzle, also further contributes to a laminar flow. 
         [0075]    It has been shown that the combination of an increasing annular area  112  in the longitudinal section  102  and a decreasing cross-sectional area in the subsequent longitudinal section  100 . 3  delivers a very good laminar flow of the urea solution even though the check valve is located in the flow path in this area. 
         [0076]    The structure of the check valve element  30  is shown again in  FIG. 5   b  in the form of an exploded representation. The fastening element  112  attached to the diffusor element  102 , which is designed as a ring, can be seen in this figure, wherein few spokes run to the diffusor element and are attached there. The ring of the fastening element  112  is carried by the second longitudinal section  102 . 
         [0077]    An alternative embodiment of a check valve element  30 ′ is shown in  FIGS. 6   a  and  6   b , wherein functionally identical parts are labelled with the same reference numbers. 
         [0078]    One of the main differences in this embodiment is that an additional cylindrical longitudinal section  100 . 4  is connected to the nozzle-like, third longitudinal section  100 . 3 , the inner diameter of which is the same in the longitudinal direction. Moreover, fastening elements  112 ′ are provided on the end  104  of the diffusor element  102 , which are supported by the second longitudinal section  100 . 2 . 
         [0079]    The functionality of this alternative embodiment of the check valve element  30 ′ is the same as that of the previously described check valve element  30  so that it can be referenced. 
         [0080]      FIG. 7  shows a schematic representation of a tank system labelled with reference number  114 . The tank system  114  comprises a tank pump  115 , which has a receiving shaft  116  for the pump nozzle  11 , which is shown here as a triangle for simplification reasons. The pump nozzle  11  is connected with the tank pump  115  via a hose  117 , wherein the hose  117  has an inner line  107  for the urea solution and an outer air or respectively gas return line preferably provided as a ring line. Moreover, electrical lines progress in the hose  117  in order to supply power to the controller in the pump nozzle on one hand and to return signals to a controller provided in the tank pump  115  on the other hand. A fast switching valve  118 , in particular a magnetic valve, is assigned to the line  117 , which can open and close the connection into the urea line  107  in the hose  117  within a few milliseconds. Moreover, a pressure sensor  119  is assigned to the inner line  107 , which is preferably provided in the area of the pump nozzle  11 . 
         [0081]    Furthermore, the tank pump  115  comprises a cleaning device  120 , which is provided to clean the pump nozzle  11  as well as the line for removing the air. 
         [0082]    To clean the pump nozzle  11 , air, which is fed to the pump nozzle  11 , either through the hose  117 , e.g. the air return channel, is used in order to clean in particular the front area of the pump nozzle. For this, it can be provided for example that the pump nozzle lies in the receiving shaft  116  in order to be able to catch the blown out urea solution. 
         [0083]    Alternatively, it is naturally also conceivable to blow the air from the cleaning device  120  to the receiving shaft  116  and there directly into the annular space  34  of the pump nozzle  11 . Alternatively, a cleaning can also be performed via a suctioning of air out of the annular space  34  of the pump nozzle. 
         [0084]    As already mentioned, the pump nozzle  11  is screwed onto the connection piece of the vehicle for filling until the operating element  22  slips. The electronics provided inside the pump nozzle  11  captures the movement of the cylindrical section  92  into the area  94  and returns a signal to the tank pump  115 . The controller provided there now detects that the pump nozzle is turned completely onto the connection piece and then releases the filling. The user then presses for example a filling button on the tank pump  115 , wherein the filling process is started. For this, the valve  118  is first released and the delivery pump can then deliver urea solution through the hose  117  and the pump nozzle  11  to the tank, wherein the pressure sensor  119  delivers control signals for regulation to the controller. The delivery rate specified by the controller is thereby set to a first value. A sensor attached to the end of the filling pipe  28 , for example in the form of two electrodes, detects the fill level inside the connection piece of the vehicle. The two electrodes required for this are provided either as separate components or the filling pipe  28  preferably serves e.g. as one of the two electrodes. As soon as the sensor is moistened by the urea solution, a corresponding fill signal is transmitted to the controller in the tank pump. In response to this signal, the controller stops the delivery pump and closes the valve  118 . 
         [0085]    If the fill signal now changes within a specifiable period of time, for example three seconds, the delivery of urea solution continues. Only when urea solution permanently, i.e. longer than the specified period of time, moistens the sensor on the filling pipe  28  is the filling completed. The controller in the tank pump  115  registers this event and prevents further filling of the vehicle. 
         [0086]    Since the sensor for capturing the fill level lies very close to the end of the filling piece of the vehicle, it must be prevented that even small amounts of urea solution spill out of the delivery pump after the stoppage. This is achieved with the valve  118  (e.g. a 3/2-way valve or a pure stop valve), which closes the line for the urea solution within a few milliseconds so that the residual amount still delivered due to the inertia of the delivery pump no longer makes its way to the hose  117 . In the case of the use of a 3/2-way valve as the valve, the residual amount is fed back to a storage tank from which the urea solution is delivered. 
         [0087]    It should be noted here that the valve  118  can naturally also be provided in the pump nozzle  11 . 
         [0088]    As already mentioned and shown in  FIG. 8 , the filling is performed with a first adjustable delivery rate dV/dt. After receipt of a first fill signal, filling now preferably continues with a second delivery rate, which is also adjustable and is less than the first delivery rate. In other words, this means that the filling first takes place at a higher delivery rate until the sensor delivers a fill signal. If this fill signal disappears after the specified period of time, it continues to be delivered, but then with the second delivery rate, which is lower. If the controller in the tank pump then receives another fill signal, it is stopped in turn and delivered again after the specified period of time as long as the fill signal has disappeared. The delivery rate can then be the same as the second delivery rate or can alternatively be further reduced. 
         [0089]    The filling with such a two-stage or multi-stage delivery rate makes it possible to fill the tank quickly on one hand and with the maximum possible fill level on the other hand. Naturally, the delivery-rate profile shown in  FIG. 8  is adjustable and changeable. 
         [0090]    It is particularly preferred to not operate the delivery pump directly with the first delivery rate during startup, but rather to slowly increase the delivery pump to this delivery rate. The “startup curve” can thereby be specified in the controller. Alternatively, the “startup curve” is permanently specified. 
         [0091]    When switching on the delivery pump again, this “startup curve” can be used again or, alternatively, delivery can proceed immediately with the second, lower delivery rate. 
         [0092]    Finally, it should be noted that the ratchet connection described above, in particular with the electronic capturing of the dipping of the trigger element into the area  94 , can also preferably be used without the other characteristics of the filling device. 
         [0093]    Overall, it has been shown that a filling device as well as a tank system are provided, which have a plurality of advantages and can nevertheless be implemented in a cost-effective manner.