Patent Publication Number: US-9421585-B2

Title: High-pressure cleaning appliance

Description:
This application is a continuation of international application number PCT/EP2009/063437 filed on Oct. 14, 2009. 
     The present disclosure relates to the subject matter disclosed in international application number PCT/EP2009/063437 of Oct. 14, 2009, which is incorporated herein by reference in its entirety and for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a high-pressure cleaning appliance comprising a first functional device required for operation in the form of a heatable heat exchanger for heating a liquid that can be discharged from the high pressure cleaning appliance, and at least one further, second functional device required for operation which is arranged below the heat exchanger. 
     High-pressure cleaning appliances of the generic kind are known in which labour-intensive disassembly of the high-pressure cleaning appliance is required to perform maintenance on the at least one second functional device which is arranged inaccessibly below the heat exchanger. Experience shows that in particular the removal of the heat exchanger in order to gain access to the at least one second functional device requires considerable time. 
     It is an object of the present invention to develop a high-pressure cleaning appliance of the kind mentioned at the outset such that it is more user friendly to maintain. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, this object is achieved in a high-pressure cleaning appliance of the generic kind by the high-pressure cleaning appliance comprising a first appliance unit having a carrying device on which the heat exchanger is held, and a second appliance unit having a support device on which the at least one second functional device is held, and by the carrying device being releasably connectable to the support device in a force-locked and/or positively-locked manner. 
     The high-pressure cleaning appliance in accordance with the invention comprises a first appliance unit and a second appliance unit including a carrying device and a support device respectively. The carrying device can be releasably connected to the support device in a force-locked and/or positively-locked manner. The high-pressure cleaning appliance can be disassembled by releasing this force-locked and/or positively-locked connection between the carrying device and the support device. This allows the first appliance unit to be brought in spaced relation to the second appliance unit. Because the heat exchanger is held on the first appliance unit and in particular on the carrying device and the at least one second functional device is held on the second appliance unit and in particular on the support device, this provides a simple and time-saving way of bringing the heat exchanger in spaced relation to the at least one second functional device. This makes it easier for a user to access the at least one second functional device for maintenance so that the high-pressure cleaning appliance in accordance with the invention proves to be more maintenance friendly than high-pressure cleaning appliances of the generic kind. 
     For maintenance, the at least one second functional device can continue to be held on the support device and/or the heat exchanger can continue to be held on the carrying device. In particular, this provides a way of performing a functional test on the high-pressure cleaning appliance when the appliance units are brought in spaced relation to each other. This saves a user from having to first fully reassemble the high-pressure cleaning appliance before a functional test can be performed after conducting maintenance on, for example, the at least one second functional device. 
     The at least one second functional device is in particular configured as a pump set for increasing the liquid pressure, and/or as a motor for the pump set, and, where applicable, as a fan for generating a flow of air cooling the motor, and/or as a blower wheel for generating a flow of combustion air for the heat exchanger, and/or as a fuel pump for delivering a fuel for the heat exchanger, and/or as an electrical device of the high-pressure cleaning appliance. Therefore, the at least one second functional device can also comprise a plurality of components of the high-pressure cleaning appliance. By way of example, it may be a unit formed by the pump set and the motor or it may be an assembly formed by the pump set, the motor, the blower wheel and the fuel pump. 
     It is advantageous for the at least one second functional device or a cover of the at least one second functional device to be freely accessible to a user after releasing the carrying device from the support device because such a high-pressure cleaning appliance is even more maintenance friendly. This can be implemented, for example, by the first appliance unit covering the second appliance unit when connected together and by the at least one second functional device being arranged on an upper side of the second appliance unit. After the carrying device and the support device have been released from one another, the first appliance unit can be brought in spaced relation to the second appliance unit for free accessibility of the at least one second functional device or, where applicable, a cover of same. 
     Preferably, the carrying device has a first carrying part for holding the heat exchanger, said first carrying part being releasably connectable to one or more support elements comprised by the support device. With the carrying device and the support device in the condition in which they are connected together, the first carrying part with the heat exchanger held thereon can be supported on the one or more support elements. This allows a force-locked connection of the carrying device with the support device by utilizing the weight exerted on the heat exchanger and thus on the first carrying part. In addition, provision may be made for the first carrying part to be connectable to the one or more support elements by use of one or more connecting elements to form an additional, releasable, positively-locked connection. 
     It is advantageous for two or more support elements to be provided, which in each case form an abutment face and in particular a support face for the first carrying part on their respective sides that face towards the first appliance unit. The first carrying part can abut the abutment face or be supported on the support face to form a force-locked connection of the carrying device with the support device. 
     A simple design of the carrying device can be achieved by the first carrying part having a plate-shaped configuration and forming a supporting surface for the heat exchanger. The heat exchanger can stand on the supporting surface, it being possible for the heat exchanger to be held by way of connecting elements on the first carrying part and thus on the carrying device. Advantageously, the plate-shaped carrying part abuts the abutment faces and is in particular supported on the support faces of the two or more support elements. By way of example, this allows a reliable force-locked connection of the carrying device with the support device to be formed utilizing the weight of the heat exchanger. 
     It is advantageous for a receiving space for the at least one second functional device to be formed below the first carrying part. If the first carrying part is of plate-shaped configuration as described above, it can delimit the receiving space for example on the upper side thereof. The receiving space may, for example, be formed by the one or more support elements projecting in a height direction starting from an upper side of the support device and forming in each case an abutment face, and in particular a support face, for the first carrying part on their respective sides that face towards the first appliance unit. Alternatively or additionally, provision may be made for the support device to form a recess for receiving the at least one second functional device which is at least partially covered on the upper side by the first carrying part. 
     It is advantageous for the carrying device to have at least one second carrying part that is fixed to the first carrying part and for the support device to comprise at least one receptacle for the at least one second carrying part. The use of the at least one second carrying part allows the carrying device to be given greater stability and the weight of the first appliance unit to be transferred to the second appliance unit in a more uniformly and better-distributed manner. 
     Preferably, the at least one second carrying part engages in a positively-locked manner in the at least one receptacle comprised by the support device. This makes it possible to form a positively-locked connection between the carrying device and the support device. By releasing the at least one second carrying part from the receptacle, it is possible to release this positively-locked connection between the carrying device and the support device. 
     To achieve a simple design of the carrying device, it has proved advantageous for the at least one second carrying part to be configured as a profile bar extending in a direction of height. The at least one receptacle of the support device for the at least one second carrying part is advantageously configured as a blind hole or as a sleeve in which the profile bar can engage in a positively-locked manner. In addition, the profile bar can be supported on the support device at a bottom of the blind hole or sleeve. This is a simple design for transferring the weight of the first appliance unit via the carrying device to the second appliance unit. 
     In a particularly advantageous embodiment of the high-pressure cleaning appliance in accordance with the invention, the first carrying part is of plate-shaped configuration as described above, and the at least one second carrying part is configured as a profile bar as described above. The profile bar extends through the plate-shaped first carrying part to achieve a stable design of the carrying device and is fixed thereto, for example by screwing. The profile bar engages in a positively-locked manner in a blind hole-like or sleeve-like receptacle of the support device, and the plate-shaped first carrying part is supported on one or more support elements of the support device and covers a receiving space for the at least one second functional device. 
     It is advantageous for the carrying device to comprise two second carrying parts because this permits the carrying device to be designed for greater stability. It is advantageous for each of the two second carrying parts to be in the form of the profile bar described above and to engage in a receptacle of the support device in a positively-locked manner. 
     On their respective upper sides, the two second carrying parts are preferably connected together by a connecting member that forms a handle element for the high-pressure cleaning appliance. For example, the user can engage the handle element to move the high-pressure cleaning appliance on a set-down surface. Furthermore, the user can engage the handle element in order to release the carrying device from the support device, thereby bringing the first appliance unit in spaced relation to the second appliance unit. 
     Preferably, the high-pressure cleaning appliance includes a housing having at least one housing wall which is held on the carrying device. By use of the housing, the functional devices of the high-pressure cleaning appliance can be protected and a more pleasing appearance can be given to the high-pressure cleaning appliance. Furthermore, retaining the at least one housing wall on the carrying device and in particular on the second carrying part thereof simplifies the construction of the high-pressure cleaning appliance. As part of the first appliance unit, the at least one housing wall can be brought in spaced relation to the second appliance unit. 
     Provision may be made for the at least one housing wall to form a rear wall of the housing. The rear wall may also form parts of side walls of the housing, for example part of a left side wall and/or part of a right side wall of the housing. 
     It is advantageous for the support device to form a trough-shaped depression in which the first appliance unit is partially arranged, wherein an edge bordering the depression abuts the side of the at least one housing wall which faces towards the support device. The second appliance unit and in particular a section of the at least one housing wall which faces towards the support device can be arranged within the depression. The at least one housing wall abuts an edge of the depression. This makes it possible to form a positively-locked connection of the edge and therefore the depression with the at least one housing wall. The at least one housing wall and with it the first appliance unit can be fixed relative to the support device and with it relative to the second appliance unit in this manner. 
     It is advantageous for the support device to form a chassis for the high-pressure cleaning appliance. The high-pressure cleaning appliance can thereby be given a simpler design. By way of example, wheels for the high-pressure cleaning appliance can be held on the chassis. The carrying device and thus the first appliance unit can be supported on the chassis. The at least one second functional device is advantageously arranged on an upper side of the chassis so that it is easily accessible to a user once the carrying device has been released from the chassis. 
     A simple and cost-effective design of the support device is obtained if it is formed in a one-piece configuration and/or made of a plastics material. 
     In the high-pressure cleaning appliance in accordance with the invention, the at least one second functional device is held on the support device. It has already been mentioned that the at least one second functional device is for example a pump set, a motor, a fan, a blower wheel, a fuel pump, and/or an electrical device of the high-pressure cleaning appliance. If the second appliance unit comprises more than only one functional device, then the high-pressure cleaning appliance can be constructed to be more compact. It is also possible for the second appliance unit to comprise a functional device receptacle for a functional device. 
     In like manner, to achieve a more compact construction of the high-pressure cleaning appliance it is advantageous for the first appliance unit to comprise, in addition to the heat exchanger, at least one further functional device required for operation of the high-pressure cleaning appliance and/or a functional device receptacle for a further functional device. 
     It is advantageous for the first appliance unit to comprise a fuel container for a fuel required for operation of the heat exchanger, and/or a hose reel to receive a high-pressure hose, and/or a handle element to move the high-pressure cleaning appliance. The fuel container is a functional device of the high-pressure cleaning appliance and the hose reel is a functional device receptacle for a high-pressure hose for operation of the high-pressure cleaning appliance. 
     Preferably, the functional devices and/or functional device receptacles for functional devices required for operation of the high-pressure cleaning appliance are all comprised by the first appliance unit and/or the second appliance unit. This allows the construction of the high-pressure cleaning appliance to be particularly compact, the functional devices or functional device receptacles all being part of the first appliance unit or the second appliance unit. 
     Preferably, the high-pressure cleaning appliance comprises a pump set for increasing the liquid pressure, said pump set being connected to the heat exchanger via a liquid discharge conduit, wherein the liquid discharge conduit can be releasably connected to the pump set and/or the heat exchanger without the use of tools. This simplifies maintenance of the high-pressure cleaning appliance. The first and second appliance units can be brought in spaced relation more easily in this manner. 
     For the same reason, it is also advantageous for electrically operative components of the high-pressure cleaning appliance to be interconnectable via one or more electrical lines without the use of tools. The electrically operative components and the one or more electrical lines may, for example, be interconnected by plug connections. The plug connections can be easily disconnected without the use of tools by the user for simplified maintenance of the high-pressure cleaning appliance. 
     It is advantageous for the high-pressure cleaning appliance to have a fuel pump for delivering the fuel required for operation of the heat exchanger, said fuel pump being connectable to a fuel container via a first fuel conduit in a maintenance-friendly manner and/or being connectable to the heat exchanger via a second fuel conduit in a maintenance-friendly manner. To this end, the first fuel conduit can, for example, be connectable to the fuel container and/or the fuel pump without the use of tools and in each case be secured by use of a fastener, clamp, or the like. In a corresponding manner, the second fuel conduit can be connectable to the fuel pump and/or heat exchanger without the use of tools and in each case be secured by use of a fastener, clamp, or the like. 
     It has already been mentioned that the at least one second functional device can take the form of a blower wheel for generating a flow of combustion air. Preferably, the first appliance unit has a housing for the blower wheel including a connection element for a combustion air channel connected to the heat exchanger, said combustion air channel being connectable to the connection element without the use of tools. This allows the first and the second appliance unit to be brought in spaced relation relative to one another in a more maintenance-friendly manner. The connection element may, for example, be configured in the form of a connection pipe over which the combustion air channel engages when the high-pressure cleaning appliance is in operation, or vice versa. 
     The following description of a preferred embodiment of the invention serves to explain the invention in greater detail in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a high-pressure cleaning appliance in accordance with the invention, including a lower part and an upper part mounted thereon and comprising a housing having a housing wall and a hood; 
         FIG. 2  is a further perspective view of the high-pressure cleaning appliance with the hood removed and two electrical devices and a fuel container omitted and the housing wall partially cut away; 
         FIG. 3  is a further perspective view of the high-pressure cleaning appliance with the hood removed and the housing wall partially cut away; 
         FIG. 4  is a further perspective view of the high-pressure cleaning appliance; 
         FIG. 5  is a perspective view of the lower part of the high-pressure cleaning appliance including a cover for functional devices of the high-pressure cleaning appliance on the upper side and with two electrical devices omitted; 
         FIG. 6  is a top view of the lower part of  FIG. 5  with the cover removed; and 
         FIG. 7  is a side view of the high-pressure cleaning appliance with the hood removed, wherein the upper part and the lower part assume a spaced relation to one another. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of a high-pressure cleaning appliance in accordance with the invention is fully or partially shown in the perspective views of  FIGS. 1 to 4  and generally designated therein by the reference numeral  10 . The high-pressure cleaning appliance  10  has a front side  12 , a back side  13 , a left side  14 , a right side  15 , a top side  16  and a bottom side  17 . 
     The high-pressure cleaning appliance  10  comprises a lower part  18 , partially shown in  FIGS. 6 and 7 , and an upper part  19  mounted on the lower part  18 , the construction of the upper part  19  being described in more detail below. The lower part  18  has a one-piece chassis  20  which is made of a plastics material and holds two wheels  23  and  24  rotatable about a common rotation axis  22  in the areas of transition from the left side  14  to the back side  13  and from the right side  15  to the back side  13 . 
     On the bottom side  17  near the front side  12 , the chassis  20  forms two support elements in the form of support legs  26  and  27 . The high-pressure cleaning appliance  10  can stand on a set-down surface  28  via the support legs  26  and  27  and wheels  23  and  24 . 
     As can be seen from  FIGS. 5 and 6  in particular, the chassis  20  forms a receptacle  30  located approximately centrally in the high-pressure cleaning appliance  10  relative to a longitudinal direction thereof and extending in a transverse direction thereof. The receptacle  30  extends from an edge  31  formed by the chassis  20  on the left side  14  up to an edge  32  formed by the chassis  20  on the right side  15 . Inserted in the receptacle  30  is an assembly  34  of the high-pressure cleaning appliance  10 . 
     The assembly  34  comprises a motor  36  having a drive shaft  40  defining a drive axis  38 , a pump set  42 , a wheel-shaped fan  44 , a blower wheel  46  and a fuel pump  48 . The pump set  42 , which is configured as an axial piston pump, is flange-connected to and forms a unit  50  with the motor  36 , which is configured as an electric motor. The pump set  42  and the fuel pump  48  form a first end near the left side  14  and a second end near the right side  15  respectively in an axial direction relative to the drive axis  38 . The motor  36  is arranged centrally within the high-pressure cleaning appliance  10  relative to the transverse direction thereof. Located axially upstream of the motor  36  relative to the drive axis  38  is the fan  44  for generating a flow of air cooling the motor  36 . Located axially upstream of the fan  44  is the blower wheel  46  for generating a flow of combustion air. The pump set  42 , the fan  44 , the blower wheel  46  and the fuel pump  48  can all be driven by the drive shaft  40 . 
     The motor  36 , the pump set  42 , the fan  44 , the blower wheel  46  and the fuel pump  48  each form a functional device of the high-pressure cleaning appliance  10  required for the operation thereof. The unit  50  and the assembly  34  as a whole can each also be regarded as a functional device of the high-pressure cleaning appliance  10 . 
     The assembly  34  is held on the chassis  20  such that the drive axis  38  is oriented horizontally and parallel to the rotation axis  22 . A cover  52  in the approximate shape of an inverted trough and extending in the transverse direction of the high-pressure cleaning appliance  10  covers the assembly  34  partially. In particular, the cover  52  covers the blower wheel  46 , the fan  44  and approximately half of the unit  50  ( FIG. 5 ). 
     In addition to the functional devices that have already been mentioned, the lower part  18  comprises two further functional devices, namely a first electrical device  54  and a second electrical device  56 . The first electrical device  54  has a housing which is approximately cuboid in shape and is held near the front side  12  in a receptacle  58  provided therefor ( FIGS. 3 and 7 ). The second electrical device  56  is releasably fixed to the upper side of the pump set  42 . 
     The chassis  20  of the lower part  18  forms a support device  60  for the above-mentioned upper part  19 , which cooperates with the support device  60  in a manner to be described hereafter. 
     Relative to the longitudinal direction of the high-pressure cleaning appliance  10 , the chassis  20  forms two support elements  62  and  63  between the cover  52  and the receptacle  58  ( FIGS. 5 and 6 ). Relative to the transverse direction of the high-pressure cleaning appliance  10 , the support element  62  is located approximately at the level of the middle of the unit  50  and the support element  63  is located approximately at the level of the fan  44 . The support elements  62  and  63  form abutment areas and in particular support areas  64  and  65  respectively on their upper sides. 
     The chassis  20  forms a further, complexly designed support element  66  opposite the support element  62  relative to the drive axis  38  approximately at the level of the rotation axis  22  relative to the longitudinal direction of the high-pressure cleaning appliance  10 . The support element  66  has a plurality of walls interconnected for reasons of stability and extending in the longitudinal and transverse directions of the high-pressure cleaning appliance  10 . The support element  66  forms a partially shoulder-shaped support area  67  on its upper side. 
     The chassis  20  forms a further support element  68  on the side of the support element  63  opposite the drive axis  38  relative to the longitudinal direction of the high-pressure cleaning appliance  10 . The support element  68  comprises a plurality of walls interconnected for rigidity and extending in a direction of height, thereby forming a grid-shaped support area  69  on its surface. The support elements  62 ,  63 ,  66  and  68  are dimensioned such that their support areas  64 ,  65 ,  67  and  69  respectively define a horizontal supporting plane for a carrying part of the high-pressure cleaning appliance  10  which is to be described hereinafter. 
     Adjacent to the support element  66  in the direction of the back side  13 , the chassis  20  forms a receptacle  70  in the form of a sleeve  71  having a bottom  72 . The sleeve  71  extends in a height direction and has a cross-section in the approximate shape of a triangle with convex sides. Correspondingly, the chassis  20  forms a receptacle  73  in the form of a sleeve  74  adjacent to the support element  68  in the direction of the back side  13 . The sleeve  74  likewise extends in a height direction, has a cross-section in the approximate shape of a triangle with convex sides, and is delimited by a bottom  75  on its underside. 
     Adjacent to the support element  68  and the sleeve  74  in the direction of the right side  15 , the chassis  20  forms a shaft-shaped receptacle  76 , the underside of which is delimited by a bottom wall  77 . 
     To connect the upper part  19  with the lower part  18  in the assembled state of the high-pressure cleaning appliance  10 , the upper part  19  has a carrying device  80  which is releasably connectable, in the manner described hereinafter, with the support device  60  formed by the chassis  20 . The carrying device  80  comprises a first carrying part  82  in the form of a flat carrier plate  84  and two second carrying parts  86  and  87  in the form of two profile bars  88  and  89 , for example of a metal material. 
     The carrier plate  84  is a one-piece construction, and made for example of a metal material, and is horizontally supported on the support areas  64 ,  65 ,  67  and  69  of the support elements  62 ,  63 ,  66  and  68  respectively. On the side thereof facing towards the front side  12 , the carrier plate  84  has two bent-over straps  90  and  91  which are releasably fixed to the support elements  62  and  63  respectively by two connecting elements, such as screws,  92  and  93  respectively ( FIGS. 2 and 3 ). Further, by way of an additional connecting element, not shown in the drawing, the carrier plate  84  is releasably connectable to the support element  66  at the shoulder-shaped support area  67  thereof. 
     The profile bars  88  and  89  are arranged in a positively-locked manner in the receptacles  70  and  73  respectively and supported on the bottoms  72  and  75  of the receptacles respectively, although this is not illustrated in the drawing. They extend in a height direction. Above the receptacles  70  and  73 , near the back side  13 , the profile bars  88  and  89  pass through through-holes  95  and  96  of the carrier plate  84  respectively ( FIGS. 2 and 3 ). The profile bars  88  and  89  are fixed, for example screwed, to the carrier plate  84  in the area of the through-holes  95  and  96  respectively. This is not illustrated in the drawing. 
     The profile bars  88  and  89  are connected together at their ends facing away from the support device  60  by a connecting member  98 . The connecting member  98  forms a handle in the form of a grip element  100  for the high-pressure cleaning appliance  10 . A user can grasp the high-pressure cleaning appliance  10  by the grip element  100  and tilt it about the support points of the wheels  23  and  24  on the set-down surface  28 . This makes it possible to move the high-pressure cleaning appliance  10  on the set-down surface  28  in a manner similar to that of a hand truck. 
     A functional device receptacle of the high-pressure cleaning appliance  10  in the form of a hose reel  102  is held on the profile bars  88  and  89  below the connecting member  98 . The hose reel  102  serves to store a high-pressure hose via which liquid pressurized by the high-pressure cleaning appliance  10  can be discharged. 
     The upper part  19  comprises a further functional device of the high-pressure cleaning appliance  10  in the form of a heatable heat exchanger  104  that is held standing upright on the carrier plate  84 . On its upper side, which faces away from the carrier plate  84 , the heat exchanger is connected to a plate-shaped holding element  106  through which the profile bars  88  and  89  extend via two through-holes. Only one of these, namely through-hole  107  through which the profile bar  88  extends, is shown in  FIG. 3  of the drawing. In the area of the through-hole  107  and the through-hole not shown, the profile bars  88  and  89  are connected to the holding element  106  in a fixed manner. This is likewise not illustrated in the drawing. 
     The heat exchanger  104  serves to heat a cleaning liquid, in particular water, pressurized by the pump set  42 . It is connected to the pump set  42  via a liquid discharge conduit  108  which is releasably fixed to the pump set  42  without the use of tools. The liquid discharge conduit  108  could also be releasably connected to the heat exchanger  104  without the use of tools. The liquid heated by the heat exchanger  104  can be discharged by way of a second liquid discharge conduit  109 , with the liquid discharge conduit  109  entering the hose reel  102  to connect to the above-mentioned high-pressure hose. 
     Combustion air for the heat exchanger  104  is generated using the blower wheel  46 , which can be driven by the motor  36 , and supplied to the heat exchanger  104  by way of a combustion air channel  110 . The combustion air channel  110  engages over a connection element  112  in the shape of a connection pipe which is formed by the cover  52  and from which it can be released without the use of tools. 
     Electrically operative components of the heat exchanger  104 , such as a thermostat arranged at the upper side thereof and not shown in the drawing, and an ignition device  114  at the upper side thereof to ignite a mixture of combustion air and fuel are connected with the first electrical device  54  via electrical lines, not shown in the drawing, by the use of plug connections. Therefore, these electrical lines can be released from the thermostat, the ignition device  114  and the electrical device  54  without the use of tools. 
     Held on the profile bars  88  and  89  is a housing wall  116  which together with a hood  118  forms a housing  120  of the high-pressure cleaning appliance  10 . The profile bars  88  and  89  are passed through the housing wall  116  below the hose reel  102  and above the holding element  106 . The housing wall  116  is arranged on the back side  13  and the left side  14  and right side  15  sections that face towards the back side. The hood  118  is arranged on the front side  12  and the left side  14  and right side  15  sections that face towards the front side and is releasably fixed to the lower part  18  and housing wall  116 . The hood  118  delimits the upper side of an interior space  122  below the housing  120 , thereby covering the above-mentioned functional devices of the high-pressure cleaning appliance  10 . 
     A lower edge  124  of the housing wall  116  engages in a positively-locked manner in an edge  126  formed by the chassis  20  on the back side  13  and on the left side  14  and right side  15  above the wheels  23  and  24  respectively. The edge  126  borders a trough-shaped depression  128 , formed by the chassis  20 , from which inter alia the support elements  66  and  68  and the sleeves  71  and  74  project and extend in a height direction ( FIGS. 4 to 6 ). In this manner, the upper part  19 , with the housing wall  116 , engages in a positively-locked manner in the lower part  18  and in particular in the chassis  20  thereof. In addition to this positively-locked connection between the upper part  19  and the lower part  18 , the previously discussed positively-locked connection by the profile bars  88  and  89  engaging in the sleeves  71  and  74  and the force-locked connection by the carrier plate  84  being supported on the support elements  62 ,  63 ,  66  and  68  exist between the upper part  19  and the lower part  18 . 
     Held on the housing wall  116  adjacent to the heat exchanger  104  near the right side  15  is a functional device of the high-pressure cleaning appliance  10  in the form of a fuel container  130  for a fuel required for operation of the heat exchanger  104 . The fuel container  130  is arranged in an interspace between the heat exchanger  104  and the housing  120  and forms a support element  132  ( FIG. 7 ) which engages in the shaft-shaped receptacle  76  in a positively-locked manner and abuts the bottom wall  77  thereof. This forms an additional positively-locked connection between the upper part  19  and the lower part  18 . 
     The fuel container  130  is connected by a first fuel conduit, not illustrated in the drawing, to the fuel pump  48 , which is connected to the heat exchanger  104  by a second fuel conduit, likewise not shown in the drawing. In this manner, the heat exchanger  104  can be supplied with fuel by use of the fuel pump  48 . The first fuel conduit and the second fuel conduit are connected, in a releasable and maintenance-friendly manner, to the fuel container  130  and fuel pump  48  and to the fuel pump  48  and heat exchanger  104  respectively and are in each case fixed thereto with a fastener, clamp, or the like. 
     The high-pressure cleaning appliance  10  in accordance with the invention is distinguished by being maintenance friendly despite its compact design, in which the assembly  34  is installed below the heat exchanger  104 . To expose the assembly  34 , the user can remove the hood  118  of the housing  120  so that the high-pressure cleaning appliance  10  essentially appears to the user as indicated by  FIG. 3 . To release the upper part  19 , which forms a first appliance unit  134  of the high-pressure cleaning appliance  10 , from the lower part  18 , which forms a second appliance unit  136  of the high-pressure cleaning appliance  10 , the user can, for example, subsequently proceed as follows: 
     The user can release the connecting elements  92  and  93 , which connect the carrier plate  84  to the support elements  62  and  63  respectively, and the third connecting element, not shown in the drawing, which connects the carrier plate  84  to the support element  66 . The liquid discharge conduit  108  can be released from the pump set  42  without the use of tools. Furthermore, the electrical lines, not shown in the drawing, can be released without the use of tools. The fuel conduits, likewise not illustrated in the drawing, can be released for example from the fuel pump  48 , heat exchanger  104  or fuel container  130 . 
     Subsequently, the upper part  19  can be brought in spaced relation relative to the lower part  18 , for example by a user grasping the upper part  19  by the grip element  100 . This releases the connection between the carrying device  80  and the support device  60 , in particular the force-locked connection of the carrier plate  84  with the support elements  62 ,  63 ,  66  and  68  and also the positively-locked connection of the profile bars  88  and  89  with the receptacles  70  and  73  respectively. In addition, the positively-locked connection between the lower edge  124  of the housing wall  116  and the edge  126  of the chassis  20  is released, as is the positively-locked connection between the support element  132  of the fuel container  130  and the receptacle  76 . 
     The combustion air channel  110  is released from the connection element  112  automatically when the upper part  19  is brought in spaced relation relative to the lower part  18  because the combustion air channel  110  simply engages over the connection element  112 . 
     Subsequently, the high-pressure cleaning appliance  10  can, for example, essentially assume the relative arrangement of the upper part  19  and the lower part  18  to each other as indicated by  FIG. 7 . A receiving space  138  formed below the carrier plate  84  and covered by the latter on the upper side is freely accessible to the user in this manner. The assembly  34  is arranged in the receiving space  138  so as to be partially covered by the cover  52 . Therefore, the lower part  18  essentially appears to a user as shown in  FIG. 5 , with the electrical devices  54  and  56  additionally arranged on the lower part  18 . 
     The cover  52 , now freely accessible to the user, can be easily released by the user so that he/she has access to the complete assembly  34 , the individual components thereof and thus to numerous functional devices of the high-pressure cleaning appliance  10 . The user can perform the necessary maintenance work on these functional devices. 
     It is, in particular, possible to perform a test operation of the high-pressure cleaning appliance  10  when the latter is in the disassembled state. In order to accomplish this, the above-mentioned fuel conduits, electrical lines, and a liquid discharge conduit that assumes the function of the liquid discharge conduit  108 , or the liquid discharge conduit  108  itself would have to be functionally reconnected. During the test run, the assembly  34  can continue to be held on the support device  60  and the heat exchanger  104  can continue to be held on the carrying device  80 . 
     It is clear from the above-described exemplary procedure used to bring the upper part  19  in spaced relation to the lower part  18  that the high-pressure cleaning appliance  10  is distinguished by being very maintenance friendly. Functional devices, in particular the assembly  34  and its components, arranged in the receiving space  138  below the carrier plate  84  can be easily accessed by a user once the carrying device  80  has been released from the support device  60 . 
     Furthermore, the high-pressure cleaning appliance  10  is distinguished by being easily reassembled. To this end, the user can proceed, for example, in reverse order to that described above for separating the upper part  19  and lower part  18  from one another.