Method and cleaning device for cleaning the interior of a pipe

Abstract

The invention relates to a method for cleaning the interior of a pipe (12) using a cleaning device (1) which has a tube (47). The tube (47) is moved within the pipe (12) in an axial direction along a main axis H, and the insertion depth E of the tube (47) into the pipe (12) is detected. According to the invention, it is determined whether the tube (47) has reached an end position, and the axial movement is terminated when the tube (47) reaches the end position.

Description

[0001] The present invention relates to a method for cleaning the inside of a pipe, in particular a pipe with open ends, and a cleaning device.

[0002] Pipes with open ends are used in heat exchangers, condensers, and air coolers, for example. These pipes can be grouped in so-called tube bundles. During operation, the pipe ends are connected to a circuit through which a medium, such as a coolant, is conveyed. The pipes must be cleaned from time to time because, over time, deposits and / or contaminants build up inside the pipes. These deposits usually originate from the medium conveyed through the pipes. If the deposits become too large, not enough medium can be conveyed through the pipes, or a pipe may become completely blocked.

[0003] Methods and devices for cleaning the inside of pipes with open ends are already known from the state of the art.

[0004] WO 2015 / 144889 A1 discloses a method and a device for cleaning pipe bundles, in which a cleaning device with a cleaning mechanism is provided. The cleaning mechanism has a high-pressure hose that is pushed into a pipe by means of a propulsion device. For this purpose, the propulsion device has a drive roller and a pressure roller. The high-pressure hose (HP hose) has a nozzle at its front end. Liquid is passed through the hose under high pressure and flows out of openings in the nozzle, whereby contaminants in the pipe can be removed. The liquid flowing out of the openings of the nozzle in the form of jets comminutes the contaminants and loosens them from the inside of the pipe.

[0005] Further devices for cleaning tube bundles are known from DE 34 188 35 C2, EP 3 757 504 A1, US 2020 / 0056851 A1 and US 2013 / 0287943 A1.

[0006] When cleaning, it is important to note that the fluid jet emerging from the nozzle attached to the front end of the hose can cause damage to surrounding equipment and injury to bystanders if the nozzle is not in the pipe. The object of the invention was to prevent such damage and injury.

[0007] This object is achieved by a method for cleaning the interior of a pipe by means of a cleaning device comprising a hose according to claim 1 and a cleaning device according to claim 9. In the method according to the invention, the hose is set into an axial movement within the pipe along a main axis H, wherein an insertion depth E of the hose into the pipe is detected. According to the invention, it is determined whether the hose has reached an end position, and the axial movement is terminated when the hose reaches the end position.

[0008] The cleaning device according to the invention comprises a hose and a propulsion unit for moving the hose along a main axis H of the propulsion unit, wherein the propulsion unit has a propulsion mechanism that is frictionally connected to the hose and by means of which the hose can be set into axial movement along the main axis H. The cleaning device comprises a controller for controlling the propulsion mechanism. The controller is configured to determine whether the hose has reached an end position and to terminate the axial movement when the hose reaches the end position.

[0009] The cleaning device preferably has a monitoring device connected to the controller, which is configured to detect the insertion depth E of the hose into the pipe. The controller is further configured to compare the detected insertion depth with a target value and thus determine whether the hose has reached an end position. Additionally or alternatively, the cleaning device has at least one limit switch unit connected to the controller, which is configured such that it can detect when the hose has reached an end position. If the cleaning device has a monitoring device and a limit switch unit, the reaching of the end position is determined redundantly.

[0010] Before cleaning the pipe, one or more end positions for the hose can be defined, with the hose's movement automatically stopping when it reaches one of the end positions. This ensures that the hose is not moved beyond the end positions by the propulsion. The hose or its nozzle therefore does not reach areas where the fluid jet could cause damage or injury. In particular, it can prevent the nozzle from being moved out of the pipe at one or both ends.

[0011] The advantages of the invention are evident in both fully automatic and semi-automatic operation. In fully automatic operation, the control system controls the propulsion according to a predefined plan. In semi-automatic operation, the operating personnel manually press buttons to move the hose forward and backward, which triggers the corresponding control of the propulsion. If the hose is moved to the end position unintentionally or due to an error, the propulsion is automatically deactivated. This prevents damage and injuries.

[0012] A hose differs from a cleaning lance primarily in its elasticity, which allows it to clean even non-straight pipes. A cleaning lance is rigid. A cleaning lance can only be used to clean straight pipes. The hose is preferably a high-pressure hose. The hose is preferably made at least partially of a plastic, in particular an elastomer. The hose can have a reinforcing insert, in particular a wire insert. It is particularly advantageous if the hose is made at least partially of rubber.

[0013] The hose is preferably connected to a source of cleaning medium, in particular a source that provides water under high pressure of up to 3000 bar.

[0014] At a front end of the hose, a nozzle with one or more outlet holes for cleaning medium is preferably provided.

[0015] The end position, with respect to which it is determined whether the hose has reached it, can be a first end position in which the hose reaches at least partially into the pipe, or a second end position in which the hose is completely outside the pipe. The first end position is usually a position in which the hose extends through the entire pipe, i.e. all the way to a rear end of the pipe. However, the end positions can also be selected such that the nozzle is arranged in the pipe in both cases and is located at the rear end of the pipe in the first end position and at a front end of the pipe in the second end position. In this case, liquid flowing out of the nozzle under high pressure outside the pipe is completely avoided.

[0016] Preferably, it is determined whether the hose has reached an end position by detecting the hose hitting a limit switch. The hose hitting a limit switch is a single event, and its detection is more reliable than, for example, determining the end position via the insertion depth E. The limit switch is preferably part of the limit switch unit of the cleaning device.

[0017] Each limit switch unit of the cleaning device preferably has a stop element mounted on the hose and a limit switch mounted on the propulsion unit, wherein the limit switch unit is configured to transmit a limit switch signal to the controller when the stop element strikes the limit switch. The controller can then deactivate the propulsion. The position of the stop element mounted on the hose can be easily adjusted, thereby determining the end position of the hose. The stop element preferably consists of two or more parts that define an opening, can be placed around the hose, and can be connected to one another such that a frictional connection is created between the hose and the stop element.

[0018] The limit switch preferably has at least one hollow shaft preloaded in the axial direction, with the hose extending through the hollow shaft. The limit switch can additionally have a fork-shaped stop part. The fork-shaped stop part, in particular, has an opening that is larger than the cross-section of the hose but smaller than the cross-section of a nozzle attached to the hose and / or a compression joint between the nozzle and hose. In this way, the nozzle and / or the compression joint remains, so to speak, suspended on the fork-shaped stop part and thus triggers the limit switch.

[0019] The hollow shaft is preferably preloaded by a compression spring. This cushions the impact of the stop element against the limit switch. This reduces the likelihood of the stop element becoming detached from the hose.

[0020] The limit switch preferably has a sensor connected to the control system, wherein the sensor is configured to detect movement of the hollow shaft counter to the preload. When the stop element strikes the hollow shaft, the hollow shaft is moved counter to its preload, which is detected by the sensor. The sensor then transmits the limit switch signal to the control system, whereupon the control system deactivates the drive.

[0021] The sensor is preferably an inductive sensor. During proper use, the hose and other components of the cleaning device may become contaminated. Inductive sensors are insensitive to such contamination.

[0022] The hollow shaft preferably has a recess toward which the sensor is directed. The recess preferably runs perpendicular to the main axis H. When the hollow shaft moves, the recess is moved away from the sensor, thereby changing the sensor's measurement signal. This change is transmitted to the controller as a limit switch signal.

[0023] Particularly preferably, two limit switch units are provided, each with a hollow shaft preloaded in the axial direction, a stop element, and a sensor, wherein the hollow shafts are preloaded in opposite directions. In this way, two end positions, a start position and an end position, are defined for the movement of the hose.

[0024] During the axial movement, the distance A between the hose and a setpoint assigned to the end position in the direction in which the hose is moving is continuously determined, and a propulsion speed of the axial movement is set depending on the determined distance. The distance A is determined from the detected insertion depth E and the setpoint assigned to the end position. The direction of movement of the hose is specified by the cleaning device by means of the propulsion. The distance A is advantageously calculated as the difference between the setpoint of the end position in the direction in which the hose is moving and the currently detected insertion depth E. If the distance A is ≤ 0, the axial movement is advantageously ended, i.e. the propulsion speed is set to zero.The setpoint of the end position can in turn be calculated from the length of the pipe to be cleaned in conjunction with a starting position in which the nozzle enters the pipe, if necessary minus a safety length, and programmed into the control or monitoring device.

[0025] If both a determination of the distance A and a dependent control of the axial movement as well as a determination of the impact of the hose are provided, the approach to the end position can be monitored redundantly.

[0026] Preferably, the propulsion speed is set to a constant first value W1 for a distance of A > 50 cm and to a constant second value W2 < W1 for a distance of A ≤ 50 cm. The hose is therefore moved more slowly near the end positions than in the middle areas of the pipe. This reduces the force when the hose hits the limit switch. This prevents, in particular, the stop element from detaching from the hose when it hits the limit switch. In addition, at the moment of impact, the lower speed means less slippage between the propulsion device and the hose and less abrasion on the hose caused by friction between the propulsion device and the hose.

[0027] Alternatively, the second value W2 can be selected depending on the distance A, with W2 decreasing as the distance A decreases. In this way, the axial movement is reduced evenly. However, the second value W2 should not fall below a certain level, since very small axial movements can damage the pipe due to the prolonged exposure to the liquid jet. Therefore, a lower limit of 0.5 • W1 is particularly preferred for the second value W2.

[0028] Regardless, the propulsion speed is preferably between 1 mm / s and 500 mm / s. The values W1 and W2 are preferably within this range.

[0029] Preferably, if the hose is detected hitting a limit switch, it is determined whether the determined insertion depth E is within a specified tolerance range around a target value assigned to the end position. Furthermore, at least one of the following actions is preferably performed if the insertion depth E is outside the tolerance range: the target value is redefined depending on the determined insertion depth E; an entry is stored in a database indicating that the insertion depth E was outside the range; a perceptible signal, in particular an acoustic signal or a light signal, is emitted; cleaning is aborted.

[0030] Ideally, the determined insertion depth E is exactly the specified target value. In this case, no further action is necessary, although even in such a case a corresponding entry can be saved in the database. The database is part of the control system. In reality, however, it can happen that the determined insertion depth E and the target value differ. One reason for this could be slipping of the stop element on the hose. The insertion depth E of the hose would then be determined correctly, but the deactivation of the propulsion would occur at the wrong time. Another reason for a deviation could be slippage between the propulsion system and the hose, which leads to incorrect determination of the insertion depth E.In any case, it is advantageous to inform the cleaning device operator of any deviations between insertion depth E and the target value so that the operator can take appropriate measures to check the functionality of the cleaning device and, if necessary, restore it.

[0031] The type of action can depend on the magnitude of the deviation. For example, if the deviation is relatively small, only an entry can be made in a database to indicate this. For a larger deviation, a signal can be issued, and for an even larger deviation, cleaning can be aborted. This alerts the operating personnel to potential problems early on without prematurely restricting the functionality of the cleaning device.

[0032] The propulsion unit preferably comprises one or more rollers that are frictionally connected to the hose. A positive connection would require a special hose, which would make the cleaning device more expensive to manufacture. The frictional connection avoids this. The rollers are preferably each rotatably mounted in the propulsion unit, in particular about a rotational axis that is skewed to the main axis H and arranged in a plane perpendicular to the main axis H.

[0033] Particularly preferably, a plurality of rollers are provided, each of which can rotate about a rotational axis, wherein the rotational axes run parallel to one another. It is considered particularly advantageous if the rollers are arranged opposite one another with respect to the hose. The rollers are then pressed against the hose in opposite directions. This clamps the hose between the rollers, increasing the frictional adhesion and reducing slippage. For this purpose, at least one of the two rollers is preferably arranged on an eccentric element. The position of this roller and thus the distance between the rollers can be changed by the eccentric element. In this way, the contact pressure can be adjusted and, if necessary, the rollers can be adapted to hoses with different diameters.

[0034] The propulsion is preferably automated or semi-automated. Advantageously, the propulsion system comprises a servomotor that drives one or more of the rollers. The rollers are preferably coupled to one another in such a way that only one roller needs to be driven by the servomotor, and all other rollers are driven via the driven roller. A servomotor enables precise axial movement of the hose. Particularly preferably, one roller is driven, and the other roller has the eccentric element.

[0035] The monitoring device for the insertion depth E is preferably at least partially integrated into the servomotor. The insertion depth E is particularly preferably measured using a rotation angle measuring unit integrated into the servomotor. The rotation angle measuring unit then forms the monitoring device. This eliminates the need for any additional measuring devices to detect the insertion depth E.

[0036] Alternatively or additionally, the monitoring device can comprise a sensor designed to detect markings on the hose. The markings are preferably applied over the entire hose and at equal distances from one another. By detecting the markings during the axial movement, the insertion depth E can be determined.

[0037] The cleaning device preferably has a slip monitoring system for detecting slippage between the hose and the propulsion system, particularly between the rollers and the hose. This slippage distorts the detection of the insertion depth E by the servo motor. Slip monitoring determines the extent of the slippage, after which the value detected as the insertion depth E can be corrected. Slip monitoring can be implemented, for example, by measuring both the rotation angle of the servo motor and detecting markings on the hose.

[0038] The hose is under high pressure during operation. As a result of this and due to the axial movement of the hose, sections of the hose that are not in the pipe to be cleaned also move. For occupational safety reasons, the jacking unit advantageously has a hose guide that can guide the hose at least in sections. The hose guide also makes it easier to align the hose with the pipe to be cleaned. To ensure that the jack can still be in frictional contact with the hose, it is preferably provided that the hose guide is interrupted in the area of the jacking. In this way, the jack can be in frictional contact with the hose while the hose is guided in front of and behind the jacking unit.

[0039] Furthermore, a combination of a cleaning device according to the above description and a pipe to be cleaned, which extends along the main axis H, is disclosed. The pipe is in particular open at both ends.

[0040] The method according to the invention is preferably carried out using the cleaning device according to the invention.

[0041] The invention is illustrated by way of example in the drawings. It shows: Figure 1 a perspective view of a first embodiment of the device according to the invention Figure 2 a plan view of the device according to Figure 1 Figure 3 a vertical section in the longitudinal direction through the device according to Figure 1 Figure 4 shows a second embodiment of the device according to the invention in a plan view

[0042] The Figures 1 to 3 The cleaning device 1 shown comprises a frame 3 with a base 5, a support 7 and a holder 9 (see Figure 1 ). The support 7 and the holder 9 are arranged along a main axis H on the base 5, with the holder 9 being arranged in a front area 11 of the base 5 and the support 7 in a rear area 13 of the base 5. When used as intended, the front area 11 faces the pipe 12 to be cleaned and the rear area 13 faces away from the pipe 12 (see Figure 2 ). The cleaning device 1 further comprises a control system (not shown).

[0043] A plastic bushing 15 is arranged in the support 7. The holder 9 comprises a plastic block 17. The cleaning device 1 further comprises a propulsion unit 21, which is mounted in the plastic bushing 15 and the plastic block 17 and is thus rotatably mounted in the frame 3 about the main axis H.

[0044] The propulsion unit 21 comprises a central housing 23 with two coaxial openings 25, 27 along the main axis H (see Figure 3). On the outer side 29 of the housing 23 and behind the first opening 25 there is arranged a first guide block 31 which is firmly connected to the housing 23. The first guide block 31 has a first guide bore 35 which is coaxial with the first opening 25. A first hollow shaft 37 is arranged in the first guide bore 35. The first hollow shaft 37 is guided in a first bushing 38 so that it is axially displaceable relative to the first guide block 31. A first compression spring 39 is arranged between the first hollow shaft 37 and the outer side 29 of the housing 23. The first hollow shaft 37 is mounted in the plastic bushing 15 so as to be rotatable about the main axis H.

[0045] The first hollow shaft 37 has a partially conical bore 43 running along the main axis H, which merges into a cylindrical bore of the hollow shaft 37 and whose largest inner diameter is provided at one end 45. The conical bore 43 thus facilitates the insertion of a hose 47 into the first hollow shaft 37. The conical bore 43 thus chamfers the first hollow shaft 37, thereby preventing damage to the hose.

[0046] The first hollow shaft 37, together with the first compression spring 39, forms a first limit switch for a first limit switch unit of the cleaning device 1.

[0047] A first sensor bore 51 is provided in the first guide block 31, arranged perpendicular to the first guide bore 35, in which a first sensor 53 of the first limit switch unit is arranged. The first hollow shaft 37 has a first recess 55 that interacts with the first sensor 53. In the position shown, the first compression spring 39 is unloaded and the first sensor 53 is directed towards the first recess 55. The first sensor 53 is connected to the control system of the cleaning device 1, whereby the control system can determine the position of the first hollow shaft 37.

[0048] On the outer side 29 of the housing 23 and in front of the second opening 27, a second guide block 61 is arranged, which is firmly connected on the one hand to the housing 23 and on the other hand to an intermediate piece 67. The second guide block 61 has a second guide bore 63 that runs coaxially to the second opening 27. A second bushing 69 is arranged in the second guide bore 63, in which a second hollow shaft 65 of a second limit switch is arranged so as to be axially displaceable relative to the second guide block 61. A second compression spring 70 of the second limit switch is arranged in the axial direction between the second hollow shaft 65 and the outer side 29 of the housing 23. The second limit switch is part of a second limit switch unit of the cleaning device 1.

[0049] A second sensor bore 57 is provided in the second guide block 61, perpendicular to the second guide bore 63, in which a second sensor 58 is arranged. The second hollow shaft 65 has a second recess 59. In the illustrated position of the second hollow shaft 65, the second sensor 58 is directed toward the second recess 59, and the second compression spring 70 is relaxed.

[0050] The recesses 55, 59 are located on the outer sides of the first and second hollow shafts 37, 65. Thus, they are not in direct contact with the space in which the hose is located. This reduces the risk of the recesses 55, 59 becoming dirty. In other embodiments, a small-diameter through-hole can be provided in each of the recesses 55, 59. This allows, for example, water that collects in the recesses 55, 59 to drain away.

[0051] A third hollow shaft 71 running along the main axis H is connected to the intermediate piece 67 in a rotationally fixed manner and projects out of the intermediate piece 67 on the side of the intermediate piece 67 facing away from the second guide block 61.

[0052] The third hollow shaft 71 extends outside the intermediate piece 67 through a bore 73 of the plastic block 17 and projects out of the bore 73 with one end 74 on the side of the plastic block 17 facing away from the intermediate piece 67.

[0053] Inside 81 of the housing 23, two guide sleeves 83, 85 for the hose 47 are arranged (see Figure 3). The first guide sleeve 83 is arranged on the inner side 87 of the housing 23 adjacent to the first opening 25 such that its bore merges into the first opening 25. The second guide sleeve 85 is arranged on the inner side adjacent to the second opening 27 such that its bore merges into the second opening 27. Both guide sleeves 83, 85 extend coaxially to the main axis H.

[0054] To impart axial movement to the hose 47, the propulsion unit 21 has a drive roller 91 and a pressure roller 93 inside the housing 23. The rollers 91, 93 are each rotatable about a rotational axis X, Y running skewed to the main axis H, wherein the rotational axes X, Y each run in a plane perpendicular to the main axis H. Both rollers 91, 93 each have a circumferential groove 95, 97 running on their respective outer circumferences, in which the hose 47 is received during normal use. The rollers 91, 93 are rubberized in the area of the grooves 95, 97 and move the hose 47 by means of frictional engagement. The distance between the rotation axes X, Y is adjustable by means of an eccentric element (not shown) of the pressure roller 93, so that the contact pressure can be adjusted and / or hoses with different diameters can be moved through the propulsion unit 21.

[0055] The rollers 91, 93 are part of a drive 94 of the drive unit 21. The drive 94 further comprises a servomotor 99, which directly drives the drive roller 91. The rollers 91, 93 are coupled to one another via gears 100 (only one gear is shown), so that the pressure roller 93 is also driven. The servomotor 99 is connected to the control system of the cleaning device 1 and can be activated and deactivated by the control system. A monitoring device for detecting an insertion depth E of the hose 47 is integrated into the servomotor 99. The monitoring device detects the angle of rotation of the servomotor 99.

[0056] The hollow shafts 37, 65, 71, the housing 23 and the guide sleeves 83, 85 together form a hose guide 101 for the hose 47. Starting from the end 45, the hose 47 runs successively through the first hollow shaft 37, through the first compression spring 39, through the first opening 25, through the first guide sleeve 83, through the interior 81 of the housing 23, through the second guide sleeve 85, through the second opening 27, through the second compression spring 70, through the second hollow shaft 65 and through the third hollow shaft 71. At the end 74 of the third hollow shaft 71, the hose 47 emerges into the open and, when used as intended, is guided into a pipe 12 to be cleaned. The cleaning device 1 is positioned such that the pipe 12 to be cleaned runs along the main axis H (see Figure 2 ).

[0057] The hose guide 101 is interrupted between the guide sleeves 83, 85 so that the rollers 91, 93 can make contact with the hose 47 and impart an axial movement to it. The rollers 91, 93 clamp the hose 47 between their circumferential grooves 95, 97 and are thereby frictionally connected to the hose 47. Rotation of the drive roller 91 thus leads to an axial movement of the hose 47 in the hose guide 101 along the main axis H. When used as intended, the hose 47 is thus imparted an axial movement by means of the drive 94.

[0058] A nozzle (not shown) is attached to the tip 103 of the hose 47. The nozzle has a larger cross-section than the hose 47. The nozzle, located at the tip of the hose 47, has eccentrically arranged outlet holes for cleaning water.

[0059] A spherical first stop element 104 can be attached to the area of the hose 47 located in front of the first hollow shaft 37. The first stop element 104 is part of the first limit switch unit. To create redundancy, several stop elements 104 can also be provided. The stop element 104 acts as an end stop for the axial movement of the hose 47. If the hose 47 is moved along the main axis H into the pipe 12 to be cleaned and such a stop element 104 is positioned at a corresponding position on the hose 47, the stop element 104 strikes the first hollow shaft 37 when the hose 47 has reached a first end position. The first end position is defined by the position of the first stop element 104 on the hose. The first stop element 104 then presses the first hollow shaft 37 in the axial direction against the first compression spring 39 in the direction of the housing 23 (see Figure 3). The first compression spring 39 is thereby compressed and the first recess 55 is moved away from the first sensor 53. The first sensor 53 detects this movement by changing its signal, since it is now directed directly at the circumferential surface of the first hollow shaft 37. In this way, it is determined that the hose has reached the first end position. The control of the cleaning device 1 receives the changed signal from the first sensor 53 as a limit switch signal and stops the servo motor 99 so that the hose 47 is not moved further into the pipe 12. The axial movement of the hose 47 is thus terminated.

[0060] When the cleaning device 1 is put into operation, the hose 47 is manually moved from the first hollow shaft 37 through the hose guide 101 until the hose 47 emerges at the end 74 of the third hollow shaft 71. From there, it can be moved into the pipe 12 and clean its interior.

[0061] If the hose 47 is moved out of the pipe 12 after a cleaning process, it should only be moved back by the propulsion unit 94 to a predetermined point. In particular, the hose 47 should be prevented from falling completely out of the propulsion unit 21. For this purpose, the hose guide 101 is interrupted in the area of the intermediate piece 67. A fork-shaped stop part 105 of the second limit switch can be pushed onto the hose 47 in the intermediate piece 67. The stop part 105 is then secured by a cover of the intermediate piece 67, which prevents the stop part 105 from slipping off the hose 47. The stop part 105 has a clear width that is larger than the outer diameter of the hose 47, but smaller than the outer diameter of the nozzle. When the hose 47 is moved back out of the pipe 12, the nozzle strikes the stop part 105; the hose 47 has then reached its second end position.The nozzle forms the stop element of the second limit switch unit. The stop part 105 is pressed by the nozzle in the axial direction against the second hollow shaft 65 and moves the second hollow shaft 65 axially toward the housing 23 against the force of the second compression spring 70. In this way, the second sensor opening 57 is moved away from the second sensor 58. The second sensor 58 detects this movement by changing its signal, since it is now no longer directed at the second recess 59, but directly at the outer circumferential surface of the second hollow shaft 65. In this way, it is determined that the hose 47 has reached the second end position. The control of the cleaning device 1 receives the changed signal from the second sensor 53 as a limit switch signal and stops the servo motor 99 so that the hose 47 is no longer moved any further.At this point, the hose 47 is completely outside the pipe 12, but is not moved further into the hose guide 101 and thus cannot fall out of the propulsion unit 21.

[0062] In other embodiments, a second fork-shaped stop member can be provided between the inner side 87 and the second guide block 61. This creates redundancy. The second fork-shaped stop member can also be designed solely as a hose catcher and not as a limit switch. This eliminates the need for an additional sensor, and the second fork-shaped stop member still serves as an additional safety feature to prevent the hose from leaving the hose guide under pressure.

[0063] The controller continuously determines a distance A from the insertion depth E of the hose 47 and a setpoint. Each end position is assigned a setpoint. The direction of rotation of the rollers 91, 93 determines the end position toward which the hose 47 moves. The distance A is the distance between the hose 47 and the end position toward which it is moving. The controller can then determine the propulsion speed, i.e., the rotational speed of the servo motor, depending on the distance A.

[0064] The Figure 4 shows a second embodiment of the cleaning device 1 according to the invention. This embodiment corresponds in parts to the first embodiment

[0065] In this embodiment, the servomotor 99 is arranged on the propulsion unit 21 such that its servomotor axis S runs perpendicular to the rotational axis of the drive roller (both not visible here). Specifically, in this embodiment, the servomotor axis S of the propulsion unit is aligned parallel to the main axis H. This gives the cleaning device a compact design. The servomotor 99 includes a gear 113 for redirecting the drive torque from the servomotor 99 to the drive roller 91.

[0066] In this embodiment, the frame of the cleaning device 1 is installed in a frame structure 114. The frame structure 114 is cuboid-shaped and has a plurality of frame parts 116. The frame parts 116 extend along the edges of an imaginary cuboid.

[0067] In the front area 11 and the rear area 13, the frame structure 114 is closed at its end faces by a plate. In the front area 11, this prevents contaminants from the tube 12 from reaching the components of the cleaning device 1. Two carrying handles 118 are arranged on opposite sides of the frame structure 114.

[0068] The distance between the rotational axis of the drive roller and the rotational axis X of the pressure roller 93 is adjustable by means of an eccentric element with a handle 120. The eccentric element 120 moves the pressure roller 93 with its rotational axis X relative to the rotational axis of the drive roller. In this way, the contact pressure can be adjusted and / or hoses of different diameters can be moved through the propulsion unit 21. List of reference symbols

[0069] 1Cleaning device 3 5Frame Base 7Support 9Bracket 11Front section 12Tube 13Rear section 15Plastic bushing 17Plastic block 21Propulsion unit 23Housing 25First opening 27Second opening 29Outside 31First guide block 35First guide bore 37First hollow shaft 38First bushing 39First compression spring 43Bore 45End 47Hose 51First sensor bore 53First sensor 55First recess 57Second sensor bore 58Second sensor 59Second recess 61Second guide block 63Second guide bore 65Second hollow shaft 67Intermediate piece 69Second bushing 70Second compression spring 71Third hollow shaft 73Bore 74End 81Inner 83First guide sleeve 85Second guide sleeve 87Inside 91Drive roller 93Pressure roller 94Propulsion 95Circumferential groove 97Circumferential groove 99Servo motor 100Gear 101Hose guide 103Tip 104Stop element 105Stop part 113Gearbox 114Frame construction 116Frame part 118Handle 120Eccentric element with handle HMain axis SServo motor axis XRotation axis YRotation axis

Claims

1. A method for cleaning the interior of a pipe (12) using a cleaning device (1) which has a tube (47), wherein the tube (47) is moved within the pipe (12) in an axial direction along a main axis H, and wherein an insertion depth E of the tube (47) into the pipe (12) is detected, wherein it is determined whether the tube (47) has reached an end position, and the axial movement is terminated when the tube (47) reaches the end position, wherein during the axial movement, the detected insertion depth E is used in order to continuously determine the distance A of the tube (47) from a target value associated with the end position in whose direction the tube (47) moves, characterised in that an advancing speed of the axial movement is set as a function of the determined distance A.

2. The method for cleaning the interior of a pipe (12) according to claim 1, characterised in that the end position is a first end position in which the tube (47) at least partially extends into the pipe (12) or a second end position in which the tube (47) is located completely outside the pipe (12).

3. The method for cleaning the interior of a pipe (12) according to claim 1 or 2, characterised in that it is determined whether the tube (47) has reached an end position in that an abutment of the tube (47) on an end switch is detected.

4. The method for cleaning the interior of a pipe (12) according to one of claims 1 to 3, characterised in that the advancing speed is set to a constant first value W1 at a distance of A > 50 cm and to a constant second value W2 < W1 at a distance of A ≤ 50 cm.

5. The method for cleaning the interior of a pipe (12) according to claim 4, characterised in that the second value W2 is selected as a function of the distance A and decreases with decreasing distance A.

6. The method for cleaning the interior of a pipe (12) according to claim 5, characterised in that a lower limit of 0.5 • W1 is provided for the second value W2.

7. The method for cleaning the interior of a pipe (12) according to any one of claims 1 to 6, characterised in that the advancing speed is between 1 mm / s and 500 mm / s.

8. A method for cleaning the interior of a pipe (12) according to any one of claims 3 to 7, characterised in that, in the event that an abutment of the tube (47) is detected at an end switch, it is determined whether the detected insertion depth E is within a specified tolerance range around a target value associated with the end position, and at least one of the following actions is performed if the insertion depth E is outside of the tolerance range: - the target value is redefined as a function of the determined insertion depth E; - an entry is stored in a database indicating that the insertion depth E was outside the tolerance range; - a perceptible signal, in particular an acoustic signal or a light signal, is output; - the cleaning is discontinued.

9. A cleaning device (1) for conducting a method according to one of claims 1 to 8, with a tube (47) and an advancing unit (21) for moving the tube (47) along a main axis H of the advancing unit (21), wherein the advancing unit (21) has a drive (94) which is frictionally connected to the tube (47) and by means of which the tube (47) can be moved in an axial direction along the main axis (H), wherein the cleaning device (1) comprises a controller for driving the drive (94), wherein the controller is configured so as to determine whether the tube (47) has reached an end position and to terminate the axial movement when the tube (47) reaches the end position.

10. The cleaning device (1) according to claim 9, characterised in that the cleaning device (1) comprises a monitoring device connected to the controller and configured so as to detect the insertion depth E of the tube (47) into the pipe (12), and / or in that the cleaning device (1) comprises at least one end switch unit connected to the controller and configured so as to detect the reaching of an end position of the tube (47), wherein each end switch unit comprises an abutment element (104) mounted on the tube (47) and an end switch mounted on the advancing unit (21), wherein the end switch unit is configured so as to transmit an end switch signal to the controller when the abutment element (104) abuts the end switch, wherein the end switch comprises at least one hollow shaft (37, 65) biased in the axial direction, wherein the tube (47) extends through the hollow shaft (37, 65), and in that the end switch comprises a sensor (53, 58) connected to the controller, wherein the sensor (53, 58) is configured so as to detect a movement of the hollow shaft (37, 65) counter to the bias.

11. The cleaning device (1) according to claim 10, characterised in that the sensor (53, 58) is an inductively measuring sensor.

12. The cleaning device (1) according to claim 10 or 11, characterised in that the hollow shaft (37, 65) comprises a recess (55, 59) at which the sensor (53, 58) is aimed.

13. The cleaning device (1) according to any one of claims 10 to 12, characterised in that the drive (94) comprises a servomotor (99) in which the monitoring device is at least partially integrated.

14. The cleaning device (1) according to any one of claims 9 to 13, characterised by slip monitoring for detecting slip between the tube (47) and the drive (94).

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