Surface Cleaning Apparatus and Method

The present invention relates to an apparatus and method for cleaning a surface, particularly by abrasive blasting. In particular, although not exclusively, the present invention relates to an apparatus and methods for cleaning items having a complex or irregularly shaped surface and for cleaning an interior surface of a vessel, apparatus or conduit.

Abrasive blasting is used particularly to clean automotive, locomotive or aerospace parts, apparatus or vehicles. For example, abrasive blasting may be used to clean individual parts, complex assemblies comprising a plurality of parts, such as an engine, or the outer surface of a vehicle.

Abrasive blasting is performed to clean a surface of debris. For example, abrasive blasting can be used to clean a surface of oxidant and a previously applied surface finish, such as paint. Frequently, exterior surfaces of vehicles are cleaned, such as trains, aircraft or other vehicles, or parts thereof, prior to applying a surface treatment or finish.

Typically, an operator manually handles and controls a nozzle, through which an abrasive substance is emitted, the abrasive being suspended in a gaseous stream. The abrasive substance may be shot, an industrial abrasive such as a Garnet mineral, for example Almandite, or similar .

A problem has been noted in that parts or items having a complex or irregular surface profile are difficult and time consuming to clean. For example, a part having one or more blind apertures, recesses or the like may be difficult to clean.

A further problem arises in that surfaces cleaned in this way have an inconsistent surface profile and, as a result, a subsequent surface treatment or finish, such as paint, is difficult to apply and can become removed from the surface easily.

It has also been noted that surfaces cleaned using an abrasive treatment in ambient air oxidise rapidly after cleaning. It is desired to delay the onset of oxidisation .

In some applications it is required to clean an interior surface. For example, an interior of a conduit or vessel may require cleaning, or the interior or a jet engine may require periodic cleaning. In these situations, it is difficult to clean the interior surface of the vessel conduit or engine along its length and circumference .

It is an aim of the present invention to provide a method and apparatus for cleaning complex or irregularly shaped items or surface.

It is an aim of the present invention to provide a method and apparatus for cleaning a surface which produces a cleaned surface having a consistent surface profile.

It is a further aim of the present invention to provide a method and apparatus which increases a speed of surface cleaning.

It is an aim of preferred embodiments of the present invention to provide a method an apparatus for surface cleaning which delays an onset of oxidisation of a cleaned surface .

It is an aim of preferred embodiments of the present invention to provide a method an apparatus for cleaning an interior surface.

Other aims and advantages of the present invention will be apparent from the description which follows and the appended claims.

According to the present invention there is provided an apparatus and method as set forth in the appended claims. Preferred features of the invention will be apparent from the dependent claims, and the description which follows.

According to a first aspect of the present invention, there is provided an apparatus for directing a nozzle of an abrasive blasting apparatus, comprising: nozzle holding means for supporting a nozzle of an abrasive blasting apparatus; nozzle moving means for moving the nozzle holding means in first and second opposed directions; nozzle rotating means for rotating the nozzle holding means .

Preferably, a pivot point about which the nozzle holding means is arranged to pivot is movable by the nozzle moving means.

Preferably, the nozzle moving means is arranged to move the nozzle holding means in the first and second directions whilst the nozzle rotating means rotates the nozzle holding means.

Preferably, a gaseous stream emitted from the nozzle in use is directed outward from a point of rotation.

Preferably, a carriage mounted upon the nozzle moving means comprises a pivot point about which the nozzle rotating means is arranged to rotate the nozzle holding means .

Preferably, video means are provided to remotely view the operation of the apparatus.

According to a second aspect of the present invention, there is provided a method of abrasive cleaning, comprising emitting from a nozzle a gaseous stream having a blasting media suspended therein; moving the nozzle in first and second opposed directions; and rotating the nozzle.

Preferably, the method comprises remotely viewing the cleaning.

Preferably, the nozzle is reciprocatingly moved along a linear path whilst being rotated around the path of movement, such that a gaseous stream emitted from the

nozzle is outwardly directed from the point of rotation and path of movement.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

Figure 1 is a side view of a first preferred embodiment of the present invention arranged at an intermediate position;

Figure 2 is a side view of the first preferred embodiment of the present invention arranged at a first end position;

Figure 3 is a side view of the first preferred embodiment of the present invention at a second end position;

Figure 4 is an end view of the first preferred embodiment of the present invention;

Figure 5 is a view of a first end of a second preferred embodiment of the present invention arranged within a tubular conduit;

Figure 6 is a close up view of a second end of the second preferred embodiment; and

Figure 7 is a view of an abrasive blasting head of the second preferred embodiment.

Unless described otherwise, like parts of each embodiment shown in the drawings have identical reference numerals and operations, although reference numerals may not be shown in all drawings for clarity.

Referring to Figures 1-4, the first preferred embodiment of apparatus 10 comprises an elongate rodless cylinder or piston 20. Suitable rodless pistons are available from Hoerbiger-Origa Industrial Pneumatics, such as the System Plus OSP-P rodless piston, although other suitable rodless pistons and actuation means having the same function are available.

The rodless cylinder 20 pneumatically moves a carriage 21 along the length of the cylinder 20 body in first and second opposed direction. By suitable control of the rodless cylinder 20, the carriage 21 may be moved in a reciprocating manner along the length of the cylinder 20.

Mounted upon the carriage 21 is an actuator 30, such as a pneumatic piston, for example, available from Norgren, Inc, USA.

The actuator 30 comprises a body 31 which is connected to the carriage 21 and a shaft 32 which is extendable from, and retractable into, the body 31. The actuator 30 is preferably pneumatically controlled, although electric or hydraulic control may also be utilised.

The actuator 30 is mounted upon the carriage 21 so as to be in axial alignment with the cylinder 20. The carriage 21 comprises an actuator mount 22 which extends upwardly and outwardly from the cylinder 20 to provide a

mounting point 23 about which the actuator 30 is pivotally mounted. Thus, the actuator 30 is spaced apart from the carriage in order to allow pivotal movement of the actuator 30, in use, vertically upward and downward about the actuator mount 22 pivot 23 as will be explained.

A nozzle mount 40, or holder, is pivotally mounted upon a distal end of the carriage 21. The nozzle mount 40 is provided to attach a nozzle from a suitable blasting apparatus (not shown) . In use, the nozzle will emit a gaseous stream having a suitable blasting media suspended therein to clean a surface at which the gaseous stream is projected. The nozzle holder 40 retains and supports the nozzle during use. In fixed applications, the nozzle holder 40 may be integrated with the nozzle and a gaseous supply provided thereto.

The nozzle mount 40 is vertically oriented at a side of the cylinder 20, as shown in Figure 4. The nozzle holder 40 is pivotally mounted about a side of carriage 21 upon a self lubricating bush 24, so as to require minimal maintenance .

The nozzle holder 40 comprises a collar 41, through which the nozzle may be mounted and secured in use. Other means of attaching the nozzle to the holder 40 will be appreciated by the skilled person. The collar 41 is mounted upon an L-shaped support 42 pivotally mounted upon the carriage 21. The support 42 is pivotally mounted upon the carriage 21 at a pivot point 42 at a rear of the support behind the collar 41. A mounting point 43 is also provided to attach the support 42 to the shaft 32 of the actuator 30.

In operation, the cylinder 20 will cause the nozzle holder 40 to move along the length of the cylinder 20, preferably in a reciprocating manner. Such repeated movement of the nozzle will cause a surface or part being cleaned to have a consistent surface profile or finish due to repeated passes or scans of the nozzle and gaseous blasting stream over the surface or part.

The distal end of the actuator shaft 32 is pivotally connected to an upper end of the nozzle holder 40, distal from the collar 41. The pivotal mounting of the nozzle holder 40 to the carriage 21, and the actuator shaft 32 to the nozzle holder 40 are vertically aligned along a centre of the nozzle holder 40.

As shown in Figure 1, when the actuator shaft 32 is at an intermediate extension, the nozzle holder 40 is vertically oriented with the pivotal mounting points in vertical alignment. As shown in Figure 2, when the actuator shaft is at maximum extension, the nozzle holder 40 is caused to be angled in a first direction, such that the collar 41 (and a nozzle mounted therein in use) is directed at a first angle. As shown in Figure 3, when the actuator shaft 32 is at a maximum retraction, the nozzle holder 40 is caused to be angled in a second direction opposed to the first direction. A relationship between the length of actuator shaft 32 extension/retraction from the actuator body 31 and the amount of pivotal movement of the actuator 30 limits the amount of rotational movement of the nozzle holder 40. In the preferred embodiment, the nozzle holder is able to move over a 90 degree range, from vertical to ±45 degrees.

The apparatus 10 allows the position and orientation of a nozzle mounted thereto to be controlled individually.

Thus, the position and orientation of a gaseous blasting stream emitted therefrom can be controlled to clean a complex or irregularly shaped part.

Whilst individually linear movement of the nozzle holder 40 along the cylinder 20 and rotational movement of the nozzle holder 41 about the carriage 21 are desirable to enable accurate control of the nozzle position and direction, efficient surface cleaning is obtained by simultaneous control of both nozzle holder 40 position and orientation .

A method of controlling the apparatus 10 will now be described which can allow cleaning of an item having a complex surface or shape.

The cylinder 20 is controlled to move the carriage 21 to a first end thereof, as shown in Figure 2. With the carriage 21 at the first end of the cylinder 20, the actuator 30 is extended to orient the nozzle holder 40 in a first orientation. In the first orientation, the nozzle holder 40 is directed toward a point at a centre of the cylinder 20 but projected outward there-from.

The cylinder 20 is then controlled to move the carriage 21 (with actuator 30 and nozzle holder mounted thereon) toward a centre of the cylinder 20. As the carriage 21 moves toward a centre of the cylinder, the actuator is simultaneously controlled to gradually bring the nozzle holder to a vertical orientation, such that

when the carriage reaches a central part of the cylinder 20, the nozzle holder 40 is vertically oriented.

Next, the cylinder 20 is controlled to move the carriage 21 to a second end thereof. As the carriage 21 moves toward the second end of the cylinder 20, the actuator 30 is controlled to move the nozzle holder 40 from the vertical orientation to a second orientation, such that when the carriage 21 reaches the second end of the cylinder 20, the nozzle holder 40 is in the second orientation directed toward a point at a centre of the cylinder 20 but projected outward there-from.

A line projected through the pivot points of the nozzle holder 40 upon the carriage 21 and actuator shaft

31 to the nozzle carriage 40 intersects a point at a centre of the cylinder 20 but projected outward therefrom at all positions of the carriage 21 about the cylinder 20.

Thus, a gaseous blasting stream emitted from the nozzle mounted upon the nozzle holder 40 is continually directed at the intersection point. For optimal cleaning, the item to be cleaned should be arranged at the intersection point .

In use, the gaseous blasting stream emitted from the nozzle will advance the nozzle path for half of the nozzle movement, before trailing the nozzle for the remaining half. Thus, the nozzle effectively follows an arcuate path. In other words, the nozzle movement and rotation effectively changes the angle of direction of a gaseous jet with respect to the surface or item that it is arranged to be directed towards.

Control of the cylinder 20 and actuator 30 may be provided by a control unit (not shown) incorporating a microprocessor or other CPU to control a plurality of pneumatic valves.

Advantageously, a complex article, or article having a complex shape, may be cleaned using the apparatus 10 in combination with a nozzle for emitting a gaseous stream having a blasting media suspended therein. When the apparatus is controlled in the manner described above, a complex shaped article may be cleaned efficiently and the cleaned article will have an improved surface finish.

The apparatus 10 and method of control thereof may be incorporated into other known abrasive blasting cleaning apparatus .

It is known to abrasively clean articles or parts inside a chamber. The abrasive blasting media is projected into the chamber, which provides an enclosed environment for the abrasive cleaning. The apparatus 10 is suitable for mounting within such an abrasive blasting chamber. The part to be cleaned may then be placed within the chamber, preferably beneath the apparatus at the intersection point of the projected line from the nozzle holder 40. The apparatus 10 may then clean the part in an automated manner.

It is also known to use apparatus having a moveable blasting head to clean large structures, such as vehicles, trains, aircraft or the like. Examples of such apparatus are provided by US 5, 601, 479, EP 0 511 636, US

5,540,172. The apparatus 10 may be mounted upon the

moveable blasting head of such apparatus in order to more efficiently and accurately clean a surface. Further, the cleaned surface will have an improved finish.

Co-pending application GB0604156.0 by the same inventor, which is incorporated herein by reference, discloses an apparatus for cleaning a surface which incorporates a moveable blasting head having a partial enclosure for contacting against a surface to be cleaned. The apparatus 10 may be arranged within the partial enclosure to clean the surface in an improved manner.

Referring to Figures 5 to 7, the second preferred embodiment will now be described. The second preferred embodiment is particularly suited to cleaning an interior surface of a generally cylindrical vessel, conduit or apparatus. Particularly, the second preferred embodiment is effective at cleaning an interior surface of an elongate vessel conduit or apparatus. The second embodiment may be particularly employed to clean an interior surface of a jet engine.

The second embodiment 100 is shown arranged in use within a cylindrical vessel 200 having open ends.

The second embodiment, generally 100, comprises first and second end portion 101, 102 which provide support for an actuation means 103 which is arranged to move a blasting head linearly there-between and to rotate the blasting head around the longitudinal axis of movement, such that the blasting head is directable around the interior circumference of the vessel 200.

The first and second end portions 101, 102 are generally circular in shape suitable for arrangement within a tubular or cylindrical vessel 200 or conduit. An exterior periphery of each end portion is adapted for sealing against an interior surface of the vessel 200. Sealing may be achieved through a flexible skirt, although it is also envisaged that an expandable skirt may be provided which seals, through inflation, against the interior of the vessel 200.

The first end portion 101 is provided with an opening 104, through which gas may be extracted from the interior of the vessel 200 between the end portions 101, 102. In this way, used blasting material and debris removed from the vessel 200 interior may be extracted.

One or more viewing windows 105, 106 are provided in the end portions 101, 102 to enable an operator to manually inspect the interior of the vessel.

The actuation means 103 is arranged suspended between, to interpose, the first and second end portions 101, 102. The actuation means 103 is arranged generally at a central axis of the end portions 101, 102 to be central within the vessel 200. As will be explained, the actuation means 103 is rotatably mounted, to rotate 360 degrees about the central axis of the vessel 200. The actuation means 103 is mounted in the end portions 101, 102 by a pair of bearings to allow rotation about the longitudinal axis of the actuation means 103.

Further interposing the first and second end portions 101, 102 may be one or more supports 107, or braces, which

maintain the first and second end portions 101, 102 in spaced-apart relation.

The actuation means 103 is a rodless cylinder, such as that available from Hoerbiger-Origa Industrial Pneumatics, such as the System Plus OSP-P. The rodless cylinder 103 is provided with a compressed gaseous supply to ports in either end thereof. The gaseous supply to each port is controlled by suitable valves, such that relative compression and expansion of the cylinders mounted therein can be controlled, causing movement of a carriage along the cylinder as will be appreciated by the skilled person.

The rodless cylinder 103 has moveably mounted thereon a carriage 108 adapted to carry a blasting nozzle 109 and a video camera 110. The carriage 108is moveable along the length of the rodless cylinder 103 between the first and second end portions 101, 102. Thus, the carriage 108 moves the blasting nozzle 109 and video camera between the first and second end portions 101, 102.

The blasting nozzle 109 mounted upon the carriage has connected thereto a supply pipe 111, through which is provided a gaseous stream having blasting media suspended therein, as will be appreciated by the skilled person. In use, the gaseous stream having blasting media suspended therein is emitted from the nozzle 109 toward the interior surface of the vessel 200. The video camera 110 is mounted upon the carriage 108 to be directed toward the portion of the vessel 200 interior at which the gaseous stream is directed. The camera 110 provides a video output to an external monitor for an operator to view the cleaning operation during use.

An end of the rodless cylinder 103 comprises a shaft 112 arranged to protrude from the second support 102. The protruding end of the shaft 112 has mounted thereon a toothed drive wheel 113. Rotation of the drive wheel 113 causes rotation of the rodless cylinder 103 about its longitudinal axis between the end portions 101, 102 and within the vessel 200. A toothed drive belt 114 is engaged around the drive wheel 113 and a further toothed drive wheel (not shown) mounted upon a drive shaft of a stepper motor 115. The stepper motor 115 is arranged to cause rotate the rodless cylinder 103 within the vessel 200. Consequently, the orientation of the nozzle 109 within the vessel can be rotated 360 degrees about the longitudinal axis of the rodless cylinder 103.

A suitable control means, such as personal computer, microcomputer or dedicated controller can be arranged to control movement of the carriage along the rodless cylinder 103, by operation of gaseous supply valves to the cylinder, and rotation of the rodless cylinder 103, by control of the stepper motor 115. In this way, the interior of the vessel 200 may be controllably cleaned, as will be explained.

The interior of the vessel 200 may be controllably cleaned by use of the apparatus 100.

Firstly, the apparatus 100 is mounted within the vessel by arrangement of the end portions 101, 102 within the vessel 200. The end portions 101,102 are caused to seal against the interior of the vessel 200, such that cleaned debris and used blasting material may be extracted

through the opening 104 by means of a vacuum being created inside the vessel 200. A vacuum apparatus may provide suitable extraction and filtering of the extracted material .

A gaseous supply having blasting media suspended therein provided through the pipe 111 is then connected to a nozzle 109 mounted upon the carriage 108. The control means then controls movement of the carriage 108 and rotation of the rodless cylinder 103 through supply of compressed gas to the cylinder 103 and control of the stepper motor 115 respectively.

In the preferred embodiment, the carriage 108 is controlled to continually reciprocate between alternate ends of the rodless cylinder 103 between the end portions

101, 102, whilst the rodless cylinder 103 is caused to continually rotate at a slow speed. Thus, through multiple reciprocating movements of the carriage, the interior of the vessel 200 is cleaned through one or more revolutions of the rodless cylinder 103.

A particularly envisaged application of the second preferred embodiment is the interior cleaning of jet engines. The apparatus may be mounted within the engine and the interior of the engine cleaned with suitable blasting media suspended in a gaseous stream emitted from the nozzle 109.

Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be

made without departing from the scope of the invention, as defined in the appended claims.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.