AU2007201546B2 - Pipe cleaning blasting device - Google Patents

Description

13156AU ORIGINAL Complete Specification Applicant: Border Blasting Title; Pipe cleaning blasting device Address for Service: LESICAR PERRIN, 49 Wright Street, Adelaide, South Australia 5000, Australia The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 Pipe Cleaning Blasting Device FIELD OF THE INVENTION The present invention relates to an apparatus for the cleaning of the interior of pipes. In particular, the invention is concerned with an apparatus for the delivery of 5 air and sand for the purpose of blast cleaning the interior surface ofpipes. BACKGROUND OF THE INVENTION The cleaning of the interior of pipes or conduits is generally achieved by the process of blast cleaning. This involves ejecting a mixture of sand, or other abrasive material, and compressed air at high speeds against the interior surface of the pipe, 10 removing any built up deposits. The cleaning process forms part of the periodic maintenance performed and is used to dislodge and remove deposits accumulated on the interior surface of the pipe. In order to clean the desired length of pipe, the blast cleaning apparatus must be mounted in such a way that it can be moved throughout the length of the pipe and 15 be adapted to clean the full 360 degrees of the interior surface. Traditionally, the process of blast cleaning for pipe interiors has been achieved by travelling pipe cleaning units with a rotating nozzle or nozzles, adapted to effectively direct the stream of abrasive material and compressed air, at high speeds, against the entire interior surface of the pipe. 20 Problems arising from traditional blast cleaning methods result from stresses induced by the high pressure required for effective operation. High pressure, generally in the form of compressed air, is required to eject abrasive material at a sufficient velocity in order to remove any deposits found on the interior surfaces of pipes. The blast cleaning unit's rotating head or nozzles are traditionally angled and thus rotate 25 by the application of this high pressure so as to effectively clean the entire 360 degree interior surface of the pipe. At an air pressure suitable to remove stubborn deposits, the rotation of the nozzles and/or nozzle head may be up to a few thousand revolutions per minute and at such a high rotational speed, deterioration and wear are major problems.

3 The deterioration and wear arising from this high speed of rotation generally affects bearings and causes vibrations that are damaging to the entire unit. Another problem associated with sand blasting units is that the abrasive material used to clean the surfaces can wear and damage any susceptible parts. Solutions have been provided to minimise 5 the wear and deterioration of the unit and prolong its longevity, however, these prior art solutions also have inherent problems. Current methods of addressing these prior art problems involve slowing the rotational speed of the nozzle or improving the bearings and seals from which the nozzle head rotates. The slowing of the sand blasting unit's rotational speed has been achieved in the past by both frictional and non-frictional 10 braking mechanisms. Examples of frictional braking mechanisms are centrifugal, disk or drum brakes, applied to the rotating components of the unit. These braking mechanisms have inherent limitations as they introduce additional components susceptible to wear to the blasting unit. Brake linings and disks wear from the constant application required to retard the 15 rotation speed, especially at high pressure. Also, using the blasting unit while the braking mechanism is worn may result in further damage. Vibration and rotation over speed, caused by brake malfunction and/or operating the device while the brakes are worn, may result in other more expensive components of the unit deteriorating. This damage may also occur of the braking mechanism is not correctly adjusted and the 20 rotating head is allowed to rotate at a speed greater then that recommended, causing further wear on bearings and gaskets that are being worn by the abrasive nature of the material passing through under high pressures. Non frictional braking mechanisms could include the use of gears to step down the rotational speed or the use of magnets, where a non-heat generating retarding force is generated. Problems associated with these forms 25 of retardation are the lack of adjustability, introduction of further wearable components, and the inability to provide a consistent rotational speed and thus a consistent clean. It is therefore an object of the present invention to overcome the aforementioned problems and to provide the public with a useful alternative. SUMMARY OF THE INVENTION 4 Therefore in one form of the invention there is proposed a pipe cleaning device used to blast clean an interior surface of a pipe, comprising: at least one nozzle associated with a rotatable chamber; a compressed air motor mounted directly to the device and adapted to rotate said 5 chamber; a compressed air supply means adapted to supply compressed air to the motor and to the chamber; an abrasive material supply means adapted to supply abrasive material to said chamber, said abrasive material and compressed air adapted to form a mixture which is ejected out 10 through said nozzle towards the interior surface of the pipe; and wherein said compressed air motor is configured to rotate said chamber and nozzle such that a rotational speed thereof is controllable by controlling said air supply. In preference said compressed air motor is mounted alongside and parallel with said chamber, their cross sectional profile being such that said motor and chamber do not 15 exceed an internal dimension of the pipe being cleaned. Preferably said chamber has associated therewith a sprocket that engages a chain driven by said compressed air motor. Advantageously said abrasive material is sand. In preference said pipe cleaning device includes a means for guiding said device along 20 the interior of said pipe. Preferably the means for guiding the device includes a front and rear guide assembly, each said guide assembly comprising of a plurality of circumferentially spaced apart rollers adapted to follow the contours of the interior surface of said pipe. In preference the chamber is in the form of a pipe supported along its length by the use 25 of two bearings, enclosed and protected in a bearing cover. Preferably the bearings are protected from the abrasive material by a seal, said seal disallowing the escape of any air and/or abrasive material to the atmosphere.

4a In preference the device includes a plurality of nozzles. BRIEF DESCRIPTION OF THE DRAWINGS 5 . The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several implementations of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings: 5 Figure 1 illustrates a perspective view of the pipe cleaning blasting apparatus; Figure 2 illustrates a perspective view ofthe pipe cleaning blasting apparatus; and Figure 3 illustrates a side view of the pipe cleaning blasting apparatus 10 being used within a pipe; and Figure 4 illustrates a sectional view of the pipe cleaning blasting apparatus being used within a pipe. DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description of the invention refers to the accompanying 15 drawings. Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described without departing from the spirit and scope of the invention. Figure 1 shows a pipe cleaning blasting apparatus 10 including at one end a nozzle head 12, containing a plurality of nozzles 14. At the opposite end is a pipe 20 fastening member 16, adapted to fasten a pipe used to supply the device 10 with the necessary abrasive material, typically sand. Propulsion along the pipe, is achieved by dragging the apparatus 10 from the sand supply fastening member 16. The fastening member 16 is attached to a cylindrical supply pipe 18 by way of screwing the fastening member 16 onto the threaded portion of the supply pipe 18. At 25 the opposing end of the supply pipe 18 is flanged member 20 with drilled apertures for the penetration of bolts 26. A plurality of rear rollers 22 are attached to the supply pipe 18 and are adapted to guide the blasting apparatus 10 as it moves through the interior of the pipe being cleaned. The rear rollers 22 are used to effectively centre the device 10, ensuring that a consistent clean of the entire interior surface of the pipe 6 - occurs. Flanged member 20 secures a rear seal, not shown, by the action of being attached to the cylindrical bearing cover 24. This is achieved through the use of a plurality of threaded bolts 26. The threaded bolts 26 are typically welded to the bearing cover 24 and have a portion projecting from the cover. These protruding 5 portions of the threaded bolts 26 are aligned with corresponding apertures located in the flanged member 20 and nuts 28 are used to secure the flanged member 20 and the bearing cover 24. The pressure generated by the aforementioned attachment means secures the rear seal, not shown, in its optimal position and prevents sand or abrasive material from exiting the apparatus and causing any undue wear on bearings, located 10 underneath the bearing cover 24. The cylindrical bearing cover 24 contains an inner pipe 30 and two bearings, not shown. The supply pipe 18 has a portion extending past the flanged member 20 into the area enclosed by the bearing cover 24. This extended portion communicates abrasive material, typically sand, into the rotating inner pipe 30 and the resultant 15 compressed air and sand mixture is forced though the inner pipe 30 until ultimately being ejected from the nozzles 14. Forward and rear bearings, not shown, are adapted to support the inner pipe 30 during rotation, within the bearing cover 24. Attached to the bearing cover are two parallel protruding support members, one wider than the other. The narrow support member 32 is used in conjunction with a parallel wider 20 support member, not shown, and these members are used to support the compressed air motor 34 and the front roller mechanism 36. The inner pipe 30 terminates at its forward end in a flanged member 38, protruding beyond the bearing cover 24. The inner pipe flanged end 38 attaches to the output pipe 42 by means of a nut and bolt securing arrangement with the output pipe 25 flanged end 40. Bolts 45 are threaded through the aligned apertures of both flanged ends 38, 40 and secured with nuts, not shown. The output pipe 42 is physically rotated by a chain driven sprocket 44 welded to the output pipe 42. Sprocket 44 is adapted to be rotated by a chain 46 driven by a compressed air motor 34, therefore rotating the nozzle head 12 in a controlled manner. 30 Output pipe 42 contains at its forward most end a threaded flanged member 50 for attachment of the nozzle head 12 by threading cap 52 onto the flanged member 50.

7 The rotation of the output pipe 42 and its connected members, nozzle head 12 and inner pipc 30, is directly controlled by the compressed air motor 34. By introducing a method of externally generating rotational speed, the device 10 is able to utilise slower rotational speeds without the need for any additional retardation 5 mechanisms and is highly configurable. The compressed air motor 34 is fed by compressed air arriving through the two supply lines 48. These supply lines 48 also provide the compressed air needed to expel the sand from the nozzles 14. Figure 2 shows a perspective view of the device 10 with the alternate side displayed to Figure 1. Shown in this figure is the wider support member 33. This 10 member, in addition with the narrower support member 32, is adapted to support the compressed air motor 34 and the front guidance roller mechanism 36. It can be seen from this figure that the front and rear roller mechanisms 22 and 36 are adapted to guide the device 10 throughout the length of the inside of the pipe. Both mechanisms contain a plurality of spaced apart rollers 54, each of which is 15 angled to maintain appropriate contact with the inside surface of the pipe to be cleaned. Due to the rotational nature of the device 10, the roller mechanisms 36 and 22 need to be non rotative. Hence the rear roller mechanism 22 is mounted on the non-rotating supply pipe 18 and the front roller mechanism 36 is supported by the non rotating support members 32 and 33. It is also desirable for the compressed air motor 20 34 to be non-rotative also. The compressed air motor 34 is fed compressed air by the supply lines 48 and rotates a drive shaft 55. The drive shaft 55 includes a sprocket 56 so that it engages chain 46 and in turn rotates the output pipe 42 and ultimately nozzles 14. Figure 3 is a side view of the pipe blasting apparatus 10 being used within a 25 pipe 58. One of the nuts 47 is made visible in this figure and is used to fasten bolt 45 and secure the flanged ends 38, 40 of the inner pipe 30 and the output pipe 42, so as to attach these two pipes together. It can be seen from this figure that in this embodiment there are three nozzles 14 angled to direct the high speed abrasive sand-air mixture at the interior surface of the pipe 58. It is also possible to have further embodiments with 30 an alternative number of nozzles. Also illustrated is the function of the front and rear roller mechanisms 22 and 36. In this embodiment the front roller mechanism contains 8 four rollers 54 positioned and angled in such a fashion that they follow the interior surface of the pipe 58, in order to centre the device 10 to effectively clean the pipe and to reduce unnecessary wear. In the same fashion, six rollers 54 make up the rear assembly 22 and are used to guide the rear of the device 10 as it travels through the 5 pipe 58. Shown on the rear assembly 22 is one point of attachment 60 for a roller 54. In this embodiment, the device 10 is adapted to travel the length of the pipe 58 by being dragged. A cable or chain, not shown, is attached to the device 10 and a winch rechanism is used to ensure that a constant travelling speed is achieved. Propulsion of the device 10 also occurs through the action of blast cleaning the pipe 10 58. This is due to the forward angle of the nozzles 14 ejecting a high speed stream of sand and air. As the device 10 is adapted to travel rearwards, the rear roller mechanism 22 contains six rollers 54 as opposed to the front roller mechanism 36 containing four rollers 54. In a future embodiment, roller mechanisms 22 and 36 may be adapted to be 15 powered and through the action of friction between the plurality of rollers 54 and the interior surface of the pipe 58, the device 10 can be propelled. This powered roller mechanism would ensure that the device 10 is moving at a constant speed by having not only an accelerating component but a bmking component, for use when propulsion via the nozzles 14 is causing the device 10 to move too quickly. In another 20 embodiment, the angle of the projection of the stream of sand and air through the nozzles 14 may be changed, so that the device 10 can be adapted to move in the forward direction. Figure 4 illustrates a sectional view of the blasting device 10 being used to clean deposits 62 formed on the interior surface of a pipe 58. The cleaning action or 25 blasting is performed by subjecting the deposit to a stream 70 of high speed sand and air ejected from a nozzle 14. The nozzle 14 is adapted to be rotated in a controlled rotational fashion by the compressed air motor 34. Shown in this figure are the bearings and seals not previously illustrated, as well as any features located within the bearing cover 24. A rear seal 68 is used to 30 prevent sand and air exiting the device 10 and is secured between the rear bearing 66 and an extension of the flanged end 20 of the supply pipe 18, extending within the 9 bearing cover 24. Front and rear bearings 64 and 66 are also used to assist in supporting the rotation of the inner pipe 30 and it can be seen in this figure that both bearings, 64 and 66, are restrained by the bearing cover 24. Supply pipe 18 is of smaller diameter then the inner pipe 30 and is inserted 5 within the inner pipe to supply sand to the device 10. This connection minimises any sand entering the bearing cover and potentially contaminating and wearing the bearings 66 and 64 and the seal 68. A seal or gasket 72 may be secured at the connection between the flanged end of the inner pipe 38 and the flanged end of the output pipe 40. Gasket 72 is physically restrained between the two flanked pipe ends, 10 38 and 40, by the fastening of bolts 45 with nuts 47 and prevents any of the sand-air mixture from escaping into the atmosphere thus reducing the effectiveness of the device 10. Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown 15 and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus. 20 In any claims that follow and in the summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention. Dated this 7 April 2006 25 Craig Schulz By his Patent Attorneys LESICAR PERRIN

Claims (10)

1. A pipe cleaning device used to blast clean an interior surface of a pipe, comprising: at least one nozzle associated with a rotatable chamber; 5 a compressed air motor mounted directly to the device and adapted to rotate said chamber; a compressed air supply means adapted to supply compressed air to the motor and to the chamber; an abrasive material supply means adapted to supply abrasive material to said 10 chamber, said abrasive material and compressed air adapted to form a mixture which is ejected out through said nozzle towards the interior surface of the pipe; and wherein said compressed air motor is configured to rotate said chamber and nozzle such that a rotational speed thereof is controllable by controlling said air 15 supply.

2. A pipe cleaning device as in claim 1 wherein said compressed air motor is mounted alongside and parallel with said chamber, their cross sectional profile being such that said motor and chamber do not exceed an internal dimension of the pipe being cleaned. 20

3. A pipe cleaning device as in claim 2 wherein said chamber has associated therewith a sprocket that engages a chain driven by said compressed air motor.

4. A pipe cleaning device as in any one of the above claims wherein said abrasive material is sand.

5. A pipe cleaning device as in any one of the above claims wherein said pipe 25 cleaning device includes a means for guiding said device along the interior of said pipe. 11

6. A pipe cleaning device as in any one of the above claims wherein the means for guiding the device includes a front and rear guide assembly, each said guide assembly comprising of a plurality of circumferentially spaced apart rollers adapted to follow the contours of the interior surface of said pipe. 5

7. A pipe cleaning device as in any one of the above claims wherein said chamber is in the form of a pipe supported along its length by the use of two bearings, enclosed and protected in a bearing cover.

8. A pipe cleaning device as in claim 7 wherein the bearings are protected from the abrasive material supplied to said chamber by a seal, said seal disallowing the 10 escape of any air and/or abrasive material to the atmosphere.

9. A pipe cleaning device as in any one of the above claims wherein the device includes a plurality of nozzles.

10. A pipe cleaning device substantially as hereinbefore described with reference to the accompanying drawings. 15