WO 2012/041272 PCT/DE2011/001712 I Description Device for Cleaning Sewer Pipe Walls The invention relates to a device for cleaning sewer pipe walls using a cleaning fluid comprising a carriage and a nozzle carrier having a main axis and arranged in the carriage, the nozzle carrier being provided with a hose connection for the supply of cleaning fluid and a plurality of nozzles for applying the cleaning fluid that are arranged in the nozzle carrier around the main axis, the nozzle axes of said nozzles running obliquely to the main axis. A device of this type whose objective is to remove the sludge and slime adhering to the inner walls of a sewer pipe in a streak-free manner with as little fluid consumption and work effort as possible is described in DE 103 21 425 Al. In order to achieve this, the nozzle carrier is arranged in a carriage so that it can be rotated around the main axis of said nozzle carrier. The main axis runs approximately in or parallel to the longitudinal axis of the sewer pipe. The oblique orientation of the nozzles produces a swirl, which allows the nozzle carrier to rotate around the main axis, and a friction brake ensures that the rotational speed does not get too high. The fluid jet is thereby guided in the circumferential direction over the sewer wall, which facilitates a streak-free cleaning of the pipe wall. It has been shown that the mounting of the nozzle carrier in the carriage is very susceptible to malfunctions and that the friction brake is difficult to adjust. Therefore, the invention is based on the object of developing a device for cleaning pipe walls that has a simple design and operates effectively.
WO 2012/041272 PCT/DE2011/001712 2 To attain the object, the invention provides for the nozzle carrier to be connected to the carriage in a rotationally fixed manner. It has been shown that, even without a rotation of the nozzle carrier around its main axis, it is possible to achieve adequate cleaning of the sewer pipe walls. It is precisely the oblique orientation of the nozzles that makes it possible for the jet to hit the pipe wall diagonally, i.e., with a radial component, whereby the jet assumes a spiral shaped progression on the pipe wall, thereby preventing streak formation in particular. The device is designed so that the nozzles are essentially directed towards the rear, i.e., towards the hose connection. Therefore, the hose fastened to the hose connection is used, on the one hand, for supplying the fluid and, on the other hand, for inserting the device into a sewer pipe in that the thrust of the nozzles causes the device to advance in the sewer and the hose is pulled along with it. In order to achieve a deflection of the fluid in the nozzle carrier and at the same time produce a uniform supply for all obliquely disposed nozzles, it is provided that the hose connection is connected to a chamber in the nozzle carrier, with boreholes emanating from the chamber to the outer surface of the nozzle carrier into which the nozzles are inserted, and the chamber being delimited by a deflection surface opposite from the hose connection. Due to the axially symmetrical design of the deflection surface, the pressure is distributed to the nozzles free of turbulence. The design of the device is especially simple if the nozzle carrier is made of a base body and an annular nozzle head for accommodating the boreholes and the hose connection, with the deflection surface being configured on an end face of the base body, and if the nozzle head is connected to the carriage in a rotationally fixed manner, with the base DCACTIvE-22562204.1 WO 2012/041272 PCT/DE2011/001712 3 body being detachably connected to the nozzle head, but not directly to the carriage. The oblique arrangement of the nozzles produces a moment of torque around the main axis. In order to prevent the nozzle head from rotating, said nozzle head itself is arranged in the carriage in a rotationally fixed manner, while the base body is detachably connected to the nozzle head, but not directly to the carriage. The base body is preferably screwed to the nozzle head by means of a thread running coaxially to the main axis. In order to be able to moisten the region in front of the nozzle carrier or flush away coarse dirt, the base body has a longitudinal borehole leading from the end face having the deflection surface to an exterior end face, with a receptacle being provided there, which receives a plug provided with nozzle boreholes. If it is possible to dispense with a preliminary cleaning, a solid plug sealing the longitudinal borehole may be used instead of a plug having nozzle boreholes. An especially intensive and streak-free cleaning of the pipe walls is achieved by nozzles disposed obliquely on the rear side of the nozzle carrier, if the nozzles are arranged in two circles running coaxially to the main axis. In this case, the nozzles are arranged on one circle offset in the circumferential direction from the nozzles on the other circle. In addition, it may be provided that the nozzles on the outer circle have a different degree of obliqueness than the nozzles on the inner circle, which means that the distance between the nozzle axes of the nozzles on the outer circle is greater than that of the nozzle axes of the nozzles on the inner circle. The distance in this case is the length of a distance vector which runs both perpendicularly on the main axis as well as DCACTIVE-22562204.1 WO 2012/041272 PCT/DE2011/001712 4 perpendicularly to the nozzle axis. This means that the nozzles on the outer circle form a jet spiral having a lower pitch on the wall surface to be cleaned, the result being an overlapping of the spirals of the inner and outer circles, which intensifies the cleaning. The inclination of the nozzle axes from the main axis should be equally large for the nozzles on the inner circle and for those on the outer circle. Because the base points of the distance vector between the main axis and the nozzle axes for all nozzles on a circle lie at the same location on the main axis, the orientation of all nozzles on a circle is identical, so that the carriage can be used oriented in any direction in the pipe to be cleaned and always produces the same cleaning effect. The invention is explained in more detail in the following on the basis of an exemplary embodiment. The drawings show: Fig. I A longitudinal section through the device according to the invention and Fig. 2 A cross section through the device with a top view of the double circle of nozzles disposed obliquely to the main axis of the device. The device is made of a carriage I having four runners 2, which are fastened externally on a support ring 3 in a uniformly distributed manner. The runners 2 that are distributed uniformly on a circumference run substantially parallel, with the ends thereof each being DCACTIVE-22562204.1 WO 2012/041272 PCT/DE2011/001712 5 bent inwardly to develop a certain clearing effect. A nozzle carrier 4 having a main axis 5 that is parallel to the runners 2 is arranged inside the support ring 3. The nozzle carrier 4 is made of a nozzle head 6 and a base body 7. The outer circumference of the nozzle head 6 corresponds approximately to the inside diameter of the support ring 3 so that the nozzle head 6 is inserted there and held in a rotationally fixed manner by means of headless screws 8. Situated on the rear end face of the nozzle head 6 and arranged centrally is a hose connection 9 around which boreholes 12 for accommodating nozzle inserts are arranged on two circles 10, 11 running concentrically to the main axis 5. These may be designed as described in DE 10 2010 026 720 Al, the related content of which is incorporated into the present application by reference. The nozzle inserts are designed such that the nozzles point in the direction of the nozzle axes 13 depicted in the drawing. The boreholes 12 emanate from a conical ring surface 14 on the rear side of the nozzle head 6 and end in a stepped chamber 15, the side of which that is open toward the front side of the nozzle head 6 is sealed by the base body 7, which is why said base body is screwed into the chamber 15. The rear end face of the base body 7, which delimits the chamber, forms a deflection surface 16 that is rotationally symmetrical to the main axis 5, which is why the base body 7 is provided with a central taper 17 directed into the hose connection 9, the base of said taper beginning in an annular trough 18 that runs around the taper 17. The boreholes 12 for accommodating the nozzle inserts are directed at the base of the taper 17 or into the trough 18. DCACTIVE-22562204.1 WO 2012/041272 PCT/DE2011/001712 6 Running through the base body 7 in the main axis 5 is a longitudinal borehole 19, which ends at the outer end face in a receptacle for a plug 20. The plug 20 that is screwed in there has nozzle boreholes 21, 22, and namely a central nozzle borehole 21, which is directed forward in the main axis 5, as well as several lateral nozzle boreholes 22 distributed around said central nozzle borehole and directed slightly outwardly. The front end face of the plug 20 lies somewhat outside the bent ends of the runners so that the jet is able to escape unhindered to the front, thereby achieving a pre-cleaning of the pipe. As Figure 2 shows in more detail, the boreholes 12 for the nozzles lie on two circles 10, 11 coaxially to the main axis 5 of the device, and the boreholes 12a for the nozzles on the inner circle 10 are offset from the boreholes 12b for the nozzles on the outer circle 11. Because the axes of the boreholes 12a, 12b are identical to the nozzle axes 13, the boreholes 12a, 12b will also be referred to as nozzles in the following. Each circle 10, 11 has eight nozzles so that the distance between two nozzles that are offset from each other is 22.50. The nozzles are offset in turn from the runners 2 so that the jet escaping from the nozzle does not hit the runners 2. The angle of inclination that the nozzle axes 13 maintain with respect to the main axis 5 is approximately 25* in the exemplary embodiment. The angle of inclination is the angle between the nozzle axis projected at the main axis plane and the main axis, and the main axis plane is a plane in which the main axis lies and which runs perpendicularly to the distance vector between the nozzle axis and the main axis. The nozzles are substantially oriented rearward and produce a feed motion. The nozzles in this case are obliquely oriented, i.e., they do not lie in a DCACTIVE-22562204.1 WO 2012/041272 PCT/DE2011/001712 7 plane through which the main axis 5 also runs, but in a plane offset therefrom; i.e., the nozzle axes have a radial component which can be determined in reference to a nozzle plane which is produced by a rotation of the main axis plane around the main axis and in which the nozzle lies. The offset is selected in such a way that the nozzle axes enclose an angle of 5* to 100 with the nozzle plane. The orientation of the jets may also be defined via the distance of the main axis from the nozzle axes. The distance is the length of the section which is perpendicular to both the main axis and the nozzle axis. Therefore, the fluid jets escaping from the nozzles hit diagonally to the cylindrical wall surface of the pipe being cleaned, i.e., they have a radial component so that the jet deflected at the wall surface transitions into a spiral on the wall surface, expanding slightly in the process and removing adhesions from the inner wall of the pipe in a spiral-shaped band. This band may be relatively narrow so that the band region is cleaned intensively. But because the carriage advances axially, the spiral-shaped band is shifted progressively in the axial direction so that the pipe wall is cleaned over its entire circumference. Therefore, streak formation such as occurs with a purely axial orientation of the nozzles is prevented. A device for cleaning sewer pipe walls is described in the present case. Water is normally used as the fluid. However, it is also conceivable to use the device for example in exhaust ducts that are required in kitchens to suction off greasy air. Also in this case, a greasy layer forms over time on the inner walls. For this purpose, air is used as the fluid. DCACTIVE-22562204.1 WO 2012/041272 PCT/DE2011/001712 8 However, in order to develop sufficient separation force, the nozzles are likely to have a smaller diameter in this case than those used with water. DCACTIvE-22562204.1 WO 2012/041272 PCT/DE2011/001712 9 List of Reference Numbers 1 Carriage 2 Runners 3 Support ring 4 Nozzle carrier 5 Main axis 6 Nozzle head 7 Base body 8 Headless screws 9 Hose connection 10 Inner circle 11 Outer circle 12a, b Boreholes 13 Nozzle axes 14 Ring surface 15 Chamber 16 Deflection surface 17 Taper 18 Trough 19 Longitudinal borehole 20 Plug 21 Central nozzle borehole 22 Lateral nozzle boreholes DCACTIVE-22562204.1