Procedure and apparatus for the cleaning of air ducts

Abstract

 The invention relates to a procedure and an apparatus for the cleaning of air ducts. The brushing device of the invention, supported by supporting and friction brushes (2), is moved in an air duct in the transverse direction of the duct. The direction of rotation of the drive motor (1) of the apparatus is reversed by means of a pneumatic control system, enabling the brush to move back and forth in the duct so as to produce an efficient brushing result.

Description

[0001] The present invention relates to a procedure as defined in the preamble of claim 1 and an apparatus as defined in the preamble of claim 3 for the cleaning of air ducts.

[0002] Previously known is e.g. the procedure and apparatus for the cleaning of air ducts presented in Finnish patent application 902078. In this known solution, a suction fan is connected to a desired point in the piping and the connections close to the suction fan are temporarily closed. When a cleaning brush is then inserted into the duct at a point at a distance from the fan, the dust and dirt loosened by the brush are carried by the suction into the container of the suction fan. The brushing device used in this solution comprises a motor-driven brush which is supported by wheels running along the duct walls. A drawback with this known solution is that each brushing device can only be fitted for one pipe or duct size. Therefore, in ducts larger than the designed size, the brush moves along the bottom or the duct but leaves the upper part uncleaned.

[0003] The object or the present invention is to correct the drawbacks mentioned above and to achieve a new type of procedure and apparatus for the cleaning of air ducts which is cheap and reliable in operation. The procedure of the invention is characterized by what is said in the characterization part of claim 1. Similarly, the apparatus of the invention is characterized by what is said in the characterization part of claim 3. In addition, different embodiments of the invention are characterized by what is said in the characterization parts of the subclaims.

[0004] The solution or the invention has the advantage that it allows easy cleaning or ducts having a rectangular, square, elliptical or circular cross section. Moreover, the solution of the invention is applicable for the cleaning of ducts of various cross-sectional sizes. Since the brushing device also moves in the widthwise direction, it can be used to clean even ducts having a large width and a rectangular or ellipctical cross-sectional form by making use of an automatic feature for the change of the direction of rotation. In addition, a flexible spiral shaft coupler can be fitted between the shaft of the pneumatic motor and the brush fixture. This coupler enhances the sideways movement of the brushing device when required, making it easier for the brushing device to move in the corner areas of the ducts.

[0005] In the following, the invention is described in detail by the aid of an example of its embodiments by referring to the attached drawings, in which

Fig. 1

presents the brushing device in side view and partially sectioned,

Fig. 2

presents the brushing device in a rectangular air duct, seen in perspective view from above,

Fig. 3

visualizes the effect of a reversal of the direction of rotation of the pneumatic motor on the brushing action in a rectangular duct, showing the brush from behind,

Fig. 4

presents a diagram of the pneumatic control of the pneumatic motor.

[0006] To give an understanding or the procedure, the brushing device and its parts will be described first. Fig. 1 depicts the structure of the brushing device in a simplified form and partly sectioned. The device comprises a cylindrical pneumatic motor 1 rotatable in two directions. The motor imparts a rotating motion to a cleaning brush 3, the ends of which are provided with supporting and friction brushes 2 which bear and support the soft cleaning brush. The supporting and friction brushes are narrower and more rigid than the cleaning brush 3 and their diameter is smaller than that of the cleaning brush. The cleaning brush is soft and has a large diameter so as to enable it to be used for the cleaning of ducts of various sizes. The brushes are coupled by means of a rigid coupler 4 or a flexible spiral shaft coupler 5 to the front end of the pneumatic motor. The brushes are attached to the coupler by means of a dome-capped screw 10. To prevent the screw 10 from being unscrewed as a result of a change of direction of rotation of the brushes, the brushes 2, 3 and the coupler 4, 5 are connected together by means of cylindrical pins 11. Spring washers 12 prevent the screw from being loosened due to vibration. Connected to the rear end of the pneumatic motor 1 via a flexible crosspiece is a flexible working arm 6. The crosspiece has inside it a knuckle joint 13 transferring the torque and outside it a spring 7 which provides flexibility and effects a return motion. Connected to this end of the pneumatic motor 1 are also the pressure air delivery pipes 8. These as well as the working arm 6 are placed inside a protective plastic pipe 9.

[0007] Fig. 2 shows a perspective view of the brushing device in a rectangular duct. The figure visualizes the sideways motion of the brushes 2, 3 in a wide air duct. Fig. 3 illustrates the motion of the brushing device in a rectangular duct as seen from the direction of the rear end of the pneumatic motor 1. The supporting and friction brushes 2 act as friction increasing elements to produce a sideways motion and, placed on either side of the cleaning brush 3, they support the brushing device as it is brushing the duct. The use a brush oversized with respect to the height of the duct makes it possible far the brush to reach even the corners of a rectangular or square duct. Reversing the direction of rotation allows both edges of a wide duct to be reached while the intermediate area is also brushed as the brushing device moves alternately from side to side. When the direction of rotation of the brushes is changed, the brushing device always moves in the direction of rotation due to the friction generated by the brushes.

[0008] Fig. 4 shows a diagram of the pneumatic control of a reversal of direction of rotation of the pneumatic motor 1. Valve 14 is a reversing valve controlled by an auxiliary valve 15. Valves 18 and 19 are manual valves used in manual control mode, and valves 16 and 17 are timer valves regulating the duration of the working period in each direction of rotation. The pressure is supplied to the auxiliary valve via a pressure regulator 20, ensuring that variations in the pressure of the supplying pneumatic network will not affect the time settings of the timer valves. When manual valve 18 is open and manual valve 19 closed, the motor rotates in the clockwise direction, and when these valves are set vice versa, the motor rotates in the anticlockwise direction. When both manual valves are open, reversal of the direction of rotation is controlled automatically by the timer valves. Timer valve 17 is used to adjust the duration of clockwise rotation and timer valve 16 to adjust the duration of anticlockwise rotation. Both valves have a knurled-head screw for adjustment of the period.

[0009] The brushing device is moved by pushing or pulling it by the flexible working arm in the direction of the shaft of the pneumatic motor. Transverse movement is produced by reversing the direction or rotation of the motor via the pneumatic control system. The soft cleaning brush 3, supported by the supporting and friction brushes 2, moves in the air duct. The brushing device moves in the transverse direction in the duct according to the direction of rotation of the brushes, always moving towards the direction of rotation, while the cleaning device brushes the duct.

[0010] It is obvious to a person skilled in the art that the invention is not restricted to the example described above, but the invention may be varied within the scope of the claims presented below.

Claims

1. Procedure for the cleaning of air ducts, in which procedure a motor-driven brushing device provided with a cleaning brush (3) is moved in the air duct to be cleaned, characterized in that the brushing device is equipped with supporting and friction brushes (2) supporting the cleaning brush (3) and that, during the brushing, the brushing device is driven, if necessary, in the transverse direction of the duct by means of a driving motor (1), the brushing device being supported by the brushes (2, 3),

2. Procedure for the cleaning of air ducts according to claim 1, characterized in that, by reversing the direction of rotation of the drive motor (1), the brushing device is driven in the duct back and forth in the widthwise direction of the duct during brushing.

3. Apparatus for the cleaning of air ducts, comprising a pneumatic motor (1), a cleaning brush (3) mounted on a rotatable shaft at its front end and a flexible working arm (6) attached to the rear end of the motor and enabling the brushing device to be moved in the direction of the motor shaft, characterized in that the apparatus is provided with at least one supporting and friction brush (2) fitted to support the soft cleaning brush (3).

4. Apparatus for the cleaning of air ducts according to claim 3, characterized in that it has on either side of the cleaning brush, directly at each end of the cleaning brush (3), a supporting and friction brush (2) having a diameter smaller than that of the cleaning brush.

Drawing