WO2004080655A1

WO2004080655A1 - Abrasive blasting assembly

Info

Publication number: WO2004080655A1
Application number: PCT/CA2004/000376
Authority: WO
Inventors: Wayne A. Duncan; Jamie C. Davis; Patrick D. Williams
Original assignee: High Production Inc.
Priority date: 2003-03-13
Filing date: 2004-03-10
Publication date: 2004-09-23
Also published as: CA2421806A1

Abstract

An abrasive blasting assembly includes a shaft support (12), with a rotating shaft (14) supported by the shaft support (12). The shaft (14) has an input end (16) and an output (18) end. Means (22) is provided for rotating the shaft. An abrasive media line (34) is provided which is adapted to deliver abrasive media to the input end of the shaft (14). An air propellant line (36) is provided which is adapted to deliver air to the input end (16) of the shaft. At least two diverging outlet conduit (38) are mounted at the output end (18) of the shaft and adapted to create a vortex effect upon rotation of the shaft.

Description

TITLE OF THE INVENTION:

Abrasive Blasting Assembly

FIELD OF THE INVENTION The present invention relates to an abrasive blasting assembly for use in abrasive blasting metal and other

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BACKGROUND OF THE INVENTION The external surface, of crude oil storage tanks and other large steel surfaces are abrasive blasted prior to painting and coating. Abrasive blasting is required in order to provide cleanliness and anchor profile on the steel substrate for the paint to adhere to. Abrasive blasting is labour intensive and time consuming. Production is limited to between 50 and 200 square feet per man hour; if the abrasive blaster is well equipped and is accompanied by adequate ground support.

SUMMfiRY OF THE INVENTION

The present invention is an abrasive blasting assembly that provides a relatively high production method of abrasive delivery.

According to the present invention there is provided an abrasive assembly which includes a shaft support, with a rotating shaft supported by the shaft support. The shaft has an input end and an output end. Means is provided for rotating the shaft. An abrasive media line is provided which is adapted to deliver abrasive media to the input end of the shaft. An air propellant line is provided which is adapted to deliver air to the input end of the shaft. At least two diverging outlet conduit are mounted at the output end of the shaft and adapted to create a vortex effect upon rotation of the shaft during operation.

The above described multi-outlet design provides for uniform high volume abrasive deliver at up to 150 pounds per square inch (psi) . The diverging outlet conduit create a vortex effect, which amplifies the abrasive delivery while reducing abrasive media consumption. It has been found that abrasive consumption can be reduced to approximately 3.5 pounds per square foot, as compared to approximately 8 pounds per square foot with conventional systems when preparing new steel to commercial grade.

Although beneficial results may be obtained through the use of the abrasive blasting assembly as described above, even more beneficial results may be obtained when the following optional features are incorporated into the abrasive blasting assembly.

Even more beneficial results may be obtained when the diverging angle of the outlet conduit is adjustable. It is preferred that the outlet conduit diverge by not less than 0.5 degrees and not more than 15 degrees. The degree of divergence required to maintain the strongest vortex effect depends upon the distance from the working surface that the outlet conduit are positioned. The preferred working distances are 2 feet and 15 feet. At the first distance of 2 feet, it has been found that an angle of divergence of 8 to 15 degrees brings the best results. At the second distance of 15 feet, it has been found that an angle of divergence of 0.5 to 8 degrees brings the best results. All angles are expressed in terms of divergence in relation to the longitudinal axis of the rotating shaft.

Even more beneficial results may be obtained when a stationary pressurized delivery chamber is positioned at and matingly engaged with the input end of the shaft. The pressurization of the delivery chamber reduces abrasive wear by equalizing backpressure. Abrasive wear may be even further reduced through the use of a tapered wear sleeve which extends from the pressurized delivery chamber into the input end of the shaft. The tapered wear sleeve prevents abrasive media from striking in the vicinity of the connection.

Even more beneficial results may be obtained when some form of bearing or bearings are disposed between the shaft support and the shaft.

There are various types of drive systems that can be used to rotate the shaft. Beneficial results have been obtained when the means for rotating the shaft includes a drive, motor having an output, pulley, a circumferential input pulley around the shaft, and a. belt drive coupling extending between the output pulley of the drive motor and the input pulley. The drive motor provides a motive force via the belt drive coupling which rotates the shaft. It has been found that rotational speeds of between 25 and 100 RPM are sufficient to ensure that desired vortex effect is achieved.

Even more beneficial results may be obtained when a transition coupler is provided between the output end of the shaft and the outlet conduit. A divider is positioned in the transition coupler to divide flow at the output end of the shaft into two outlet streams. It has been found that the use of the divider creates a media cushion which reduces wear at the output end of the shaft and in the outlet conduit.

Even more beneficial results may be obtained when the shaft support is mounted to an unmanned lifting apparatus which is operated by remote control. Conventional abrasive blasting assemblies use compressed air, normally at 350 CFM, to provide a nozzle pressure of about 100 to 110 PSI. Due to weight and back pressure, the operation of each assembly requires one man. The height of the storage tanks can exceed 60 feet. Each man must, therefore, be equipped with fall arrest equipment. Working in close proximity to the abrasive blasting, each man must be equipped with breathing apparatus and protected against abrasive media ricochet by safety gear. The above described abrasive blasting assembly is so effective, in comparison with conventional abrasive blasting assemblies, that it can be mounted on a lifting apparatus and operated remotely.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other ...features of the invention will become more apparent from the ^• following description in. which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein:

_FIGURE 1 is a side elevation view, in section, of an abrasive blasting assembly constructed in accordance with the teachings of the present invention.

FI_GURE 2 i^{s a} partially cut away exploded perspective view of an input end of a rotating shaft of the abrasive blasting assembly illustrated in _FIGURE 1-

FI_GURE 3 is a side elevation view, in section, of the input end of a rotating shaft of the abrasive blasting assembly illustrated in _FIGUR_E 1-

_FIGURE 4 is a partially cut away exploded perspective view of an outlet end of the rotating shaft of the abrasive blasting assembly illustrated in FI_GURE 1- FI_GURE 5 is a detailed perspective view of diverging outlet conduit at the output end of the rotating shaft of the abrasive blasting assembly illustrated in _FI_GURE 1-

FI_GURE 6 is a perspective view showing unmanned remote operation of the abrasive blasting assembly illustrated in FIGURE 1-

DETULED DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment, ah abrasive blasting assembly generally identified by reference numeral 10, will now be described with reference to FI_GURE_S 1 through Q .

Referring to FI_GURE 1- blasting assembly 10 has a shaft support 12 that supports a rotating shaft 14 having an input end 16 and an output end 18. Referring to FI_GURE_S 2 ^and 3, bearings 20 are disposed between,shaft support 12 and shaft . 14.^" Referring to FI_GURE ^' if ^a drive motor 22 is provided which has an output pulley 24. Rotating shaft 14 is adapted with a circumferential input pulley 26. A belt drive coupling 28 extends between output pulley 24 and input pulley 26 such that drive motor 22 provides motive force to rotate shaft 14.

Referring to FI_GURE 2r ^a stationary pressurized delivery chamber 30 is positioned at and matingly engaged with input end 16 of shaft 14. Referring to FI_GURE 3c delivery chamber

30 is adapted with a tapered wear sleeve 32 which extends into input end 16 of shaft 14. Referring to F_IGURE t ^an abrasive media line 34, adapted to deliver abrasive media, and an air propellant line 36, adapted to deliver air, are in connection to delivery chamber 30 at input end 16 of shaft 14. Referring to _FIGURE 5_r two diverging outlet conduit 38 are mounted at output end 18 of shaft 14. Conduit 38 are adapted to create a vortex effect upon rotation of shaft 14. A transition coupler 40 is positioned between output end 18 of shaft 14 and outlet conduit 38. Referring to FI_GURE 4r

Transition coupler 40 is adapted with an internal divider 42. Divider 42 divides the flow at output end 18 of shaft 14 into two outlet streams 44, as illustrated in _FI_GURE 5- Referring to FI_GURE &_r blasting assembly 10 is mounted to a remote control, unmanned lifting apparatus 46.

Operation:

The use and operation of abrasive blasting assembly 10 will now be described with reference to FI_GURE_S 1 through g. Referring to FI_GURE It blasting assembly 10 is assembled and configured such that abrasive media line 34, pressurized delivery chamber 30, rotating shaft 14, transition coupler 40 and diverging outlet conduit 38 are in fluid connection with each_, other.:_. Air ..line. ,36_. is_. connected, to delivery chamber ,30.

Referring to FI_GURE_S 2 ^ano^ 3t shaft support 12 supports shaft 14 upon bearings 20. Referring to FI_GURE 5t in the illustrated embodiment, outlet conduit 38 may be adjusted by interchanging transition coupler 40 with another of varied specification. Referring to FI_GURE I_t upon activation of drive motor 22, motive force is applied through output pulley 24 through drive coupling 28 to input pulley 26 causing shaft 14 to rotate at variable speeds between 25 and 100 RPM. Abrasive media is delivered through abrasive media line 34 and air is delivered through air propellant line 36 at pressures of between 50 and 150 PSI. The abrasive media stream merges with the air propellant stream in delivery chamber 30. Referring to F_IGURE 3/ ^tne mixed abrasive media/air propellant stream enters input end 16 of shaft 14 with tapered sleeve 32 serving to reduce abrasive wear. Referring to F_IGURE f ^as abrasive medium passes through output end 18, divider 42 divides the flow into one of outlet conduit 38. This also serves to create a media cushion, reducing wear. Referring to FI_GURE 5c as shaft 14 rotates, outlet conduit 38 also rotate and, in doing so, create a vortex effect at outlet streams 44, amplifying the abrasive delivery. Referring to FI_GURE β_r where abrasive conditioning is to be applied to remote or perilous situations (the exterior of a large storage tank is shown) , mounting blasting assembly 10 to unmanned lifting apparatus 46 allows remote operation, avoiding the need for fall arrest precautions, protection from ricochet and other problems associated with direct human operation. This remote operation would not be possible, were it not for the superior performance of blasting assembly 10. Blasting assembly 10 delivers the abrasive media a greater distance, over a wider area and at a higher speed. The result is a more effective cleaning action which actually requires less abrasive media than conventional abrasive, blasting assemblies,

In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention as hereinafter defined in the Claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH Ml EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED S_RE DEFINED ΑS FOLLOWS:

1. An^' abrasive blast assembly, comprising: a shaft support; a rotating shaft supported by the shaft support, the shaft having an input end and an output end; means for rotating the shaft; an abrasive media line adapted to deliver abrasive media to the input end of the shaft; an air propellant line adapted to deliver air to the input end of the shaft; at least two diverging outlet conduit mounted at the output end of the shaft and adapted to create a vortex effect upon rotation of the shaft.

2. ^'ThevabrasiveVassembl as defined in Claim 1, wherein^ the . outlet conduit diverge by not less than 0.5 degrees and not more than 15 degrees.

3. The abrasive assembly as defined in Claim 1, wherein the diverging angle of the outlet conduit is adjustable.

4. The abrasive assembly as defined in Claim 1, wherein a stationary pressurized delivery chamber is positioned at and matingly engaged with the input end of the shaft.

5. The abrasive assembly as defined in Claim 4, wherein a tapered wear sleeve extends from the pressurized delivery chamber into the input end of the shaft.

6. The abrasive assembly as defined in Claim 1, wherein bearings are disposed between the shaft support and the shaft.

7. The abrasive assembly as defined in Claim 1, wherein the means for rotating the shaft includes a drive motor having an output pulley, a circumferential input pulley around the shaft, and a belt drive coupling extending between the output pulley of the drive motor and the input pulley, such that the drive motor provides a motive force which rotates the shaft.

8. The abrasive blasting assembly as defined in Claim 1, wherein a transition coupler is provided between the output end of the shaft and the outlet conduit, a divider being positioned in the transition coupler to divide flow at the output end of the shaft into two outlet streams.

9. The abrasive blasting assembly as defined in Claim 1, wherein the shaft support is mounted to an unmanned lifting apparatus which is operated by remote control.