FIELD OF THE INVENTION

[0001] This invention relates generally to a floor recovery system for use with abrasive blasting works.

BACKGROUND

[0002] Floor recovery systems that are used for abrasive blasting works have been conventionally used to remove large amounts of spent abrasives from the abrasive blasting process. Some applications of abrasive blasting works are the removal of millscale, paint and other coatings from a surface, removing rust, cutting substrates and the like. During the abrasive blasting process, abrasives such as metals, sand or synthetic materials are carried in a stream of air, at high velocities for impingement against an object to be treated. A result of this process is that large amounts of spent abrasives accumulate on the floor of the work area. Floor recovery systems are frequently used in conjunction with abrasive blasting works so that these spent abrasives can be recovered, recycled and reused.

[0003] Typically, floor recovery systems include a perforated floor above a solid floor having at least a channel therein. The blasting process is performed above the perforated floor and the spent abrasives are collected on the solid floor when it falls through the perforated floor. Scraper assemblies, screw conveyors, belt conveyors or pneumatic ducts are typically mounted above the solid floor, below the perforated floor, within the channel to transport recovered abrasive and debris. When scraper assemblies are used, they are fitted with pivoting blades which contact with the floor to convey the abrasives in a forward stroke toward a central collection channel on the floor. Once the scraper assemblies have traversed the length of the channel, they are pivoted away from the floor and conveyed in a backward stroke.

[0004] There are many types of floor recovery systems used with abrasive blasting works. An example of a floor recovery system is that described in the preceding paragraph. These floor recovery systems may utilize a wire rope powered by drive motor and gearbox, pneumatic cylinders, or chain assemblies or combination of one another to move the scraper assemblies to and fro across the length of the channel. For example, where the floor recovery system is powered by a chain assembly, the ends of the wire rope are attached to the chain and fed through a drive mounted sprocket. A disadvantage of this configuration is that as only the ends of the wire rope are attached to the chain, the length of the stroke is limited. This translates to an extremely long scraper assembly fixed with multiple blades within to counter the short stroke length. Some of the scraper assemblies used in such systems can comprise more than half the length of the channel which leads to increased wear, servicing and maintenance issues, more efforts in installation and significantly more material for construction leading to increases costs. For example, longer and bigger scraper assemblies are difficult to service due to removal of a large proportion of the floor grids to reach the scraper assemblies. Increased wear of the scraper assemblies is attributed to a larger proportion of the surface area of the scraper assemblies being subjected to rebounding abrasives during the blasting works. The same disadvantages apply to scraper floors fitted with an oscilating pneumatic cylinder located at one end of the recovery channel.

[0005] Another type of floor recovery system includes the use of belt conveyors or screw conveyors. Multiple hoppers are installed in the longitudinal channels below the perforated floor. The belt or screw conveyor lies below the multiple hoppers so that spent abrasives that fall through the perforated floor and the hoppers will land on the belt or screw conveyor to be conveyed to a central collection bucket. There are disadvantages associated with the floor recovery systems as described thus far. The first is that they make use of pneumatic cylinders and chain assemblies which requires extensive costs and maintenance to operate. Pneumatic cylinders are not designed to be used in a harsh environment like the blasting room. The limited stroke length afforded by pneumatic cylinders lead to long scraper assemblies which lead to other problems such as that mentioned above. The second is that the former floor recovery system uses very long racks fitted with multiple blades that are moved for short distances and transfers the spent abrasives from one blade to the next, which makes collection of the spent abrasives inefficient.

[0006] Another type of recovery system is a pneumatic conveying system. This system utilises a series of negative pressure fans. The recovery floor consists of a series of pneumatic conveying ducts into which the blasted abrasive falls. The abrasive and waste is then recovered by pneumatic conveying. The disadvantages associated with this type of recovery floor are that heavy abrasive particles are not easy to pneumatically convey. In order to do so high amounts of fan static pressure and airflow are required. To generate this high static power and airflow very large electric motors are required. Subsequent power consumption is extremely high for this style of recovery floor.

[0007] There is therefore an increasing need to address the deficiencies or shortcomings of the problems as presented above.

SUMMARY OF THE INVENTION

[0008] According to a first aspect of the invention, there is provided a floor recovery system for abrasive blasting works, comprising at least one rack assembly movable along each of a plurality of longitudinal channels for conveying spent abrasives from the floor of the longitudinal channel to a collector, a continuous length of cable configured for moving in a first direction to effect movement of the at least one rack assembly in the first direction along the longitudinal channel, and movable in a second direction to effect movement of the at least one rack assembly in the second direction along the longitudinal channel, and a winch drum configured for engagement with the ends of the cable, the winch drum rotatable to effect movement of the cable in the first direction and the second direction.

[0009] Preferably, the rack assemblies are attached to the continuous length of cable.

[0010] Preferably, the continuous length of cable is routed across the length of each channel alternately.

[001 1] Preferably, the winch drum is a double-sided winch drum further including a first side and a second side.

[0012] Preferably, the winch drum is rotatable in a first direction such that the first side of the winch drum draws the cable onto the drum while the second side of the winch drum releases an equivalent amount of cable off the drum simultaneously.

[0013] Preferably, the winch drum is rotatable in a second direction such that the first side of the winch drum releases the continuous cable off the winch drum while the second side of the winch drum draws the equivalent length of continuous cable onto the winch drum simultaneously.

[0014] Preferably, the rack assembly further comprises a pivoting blade pivotably mounted on the rack assembly, the pivoting blade pivotable between a first position and a second position, wherein in the first position, the pivoting blade engages the floor of the channel so as to convey the abrasives, and in the second position, the pivoting blade is raised above the floor of the channel.

[0015] Preferably, the pivoting blade further comprises a yoke positioned at a proximal end of the blade, and a clamping member for securing the yoke to the cable.

[0016] Preferably, when the winch drum is rotated to effect movement of the cable in a first direction, the cable engages the yoke of the pivoting blade such that the pivoting blade moves to the first position.

[0017] Preferably, when the winch drum is rotated to effect movement of the cable in a second direction, the cable engages the yoke of the pivoting blade such that the pivoting blade moves to the second position.

[0018] Preferably, the rack assembly further includes support members on each side of the rack assembly, wherein the support members are slidably mounted on the rail guides of the channel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order that embodiments of the invention may be fully and more clearly understood by way of non-limitative examples, the following description is taken in conjunction with the accompanying drawings in which like reference numerals designate similar or corresponding elements, regions and portions, and in which:

[0020] FIG. 1 is a plan view of a floor recovery system for abrasive blasting works, with the perforated floor grids shown; [0021 ] FIG. 2 is a plan view of the floor recovery system for abrasive blasting works shown with only a portion of the perforated floor grids;

[0022] FIG. 3 is a side view of the floor recovery system; [0023] FIG. 4 is a side view of a rack assembly; [0024] FIG. 5 is an elevation view of a rack assembly; [0025] FIG. 6 is plan view of a rack assembly. DETAILED DESCRIPTION

[0026] In the following description, the detailed embodiments of the present invention are described herein. It shall be apparent to those skilled in the art, however, that the embodiments are not intended to be limiting to the embodiments described but merely as the basis for the claims and for teaching one skilled in the art how to make and/use the invention. Some details of the embodiments are not described at length so as not to obscure the present invention.

[0027] Figures 1 and 2 illustrate a floor recovery system 10, as shown from above, for abrasive blasting works. The floor recovery system 10 is utilised in an enclosed environment or an abrasive blasting room for the purpose of recovering recyclable abrasives and contaminants from the floor after blasting. A perforated floor grating 14, as shown in Figure 1, is supported above a solid floor and allows abrasive and contaminants to drop through the floor grating 14 and onto the solid floor during the abrasive blasting works. The abrasive blasting works occur above the perforated floor grating 14. The floor recovery system 10 includes a number of longitudinal channels 18 spanning the solid floor. Each longitudinal channel 18 is fitted with a rack assembly 20 that traverses the entire length of the channel 18, which typically covers one end of the blast room to the other end of the blast room. The spent abrasives and contaminants are dropped off on a belt or screw conveyor 15. Figure 2 shows a floor recovery system 10 with a small portion of the solid floor with the perforated floor grating 14, with identical elements as shown in Figure 1. [0028] To allow for reciprocating movement of the rack assemblies 20 on the longitudinal channel 18, the rack assemblies 20 are removably detachable from a continuous cable 16 that is movable in a first direction and a second direction when in use. The continuous cable 16 travels around the longitudinal channels 18 having each end of the cable 16 attached to a rotating winch drum 13 powered by a power source (not shown). The power source can be a motor or the like. The cable 16 is arranged in a manner around the longitudinal channels 18 such that rotation of the winch drum 13 in a first direction effects movement of the rack assemblies 20 from approximately one end of the longitudinal channel 18 to the other end of the longitudinal channel 18 and rotation of the winch drum 13 in a second direction effects movement of the rack assemblies 20 in an opposed direction. The cable arrangement can be effected by a pulley arrangement which allows the cable 16 to traverse continuously around all the longitudinal channels. The length of cable 16 is configured such that the cable is routed longitudinally on each longitudinal channel 18 alternately. As only one single length of cable 16 is used for the floor recovery system, all the rack assemblies 20 are affixed to the single length of cable 16.

[0029] The winch drum 13 is a double-sided drum. One end of the cable 16 is wound round a first side of the winch drum 13 and the other end of the cable is wound round the second side of the winch drum 13. When the winch drum 13 rotates in a first direction, the cable is drawn onto the drum to effect movement of the rack assemblies 20 along the longitudinal channel 18 in the first direction. Simultaneously, the second side of the winch drum 13 rotates in an opposed direction to the first direction. At the same time, an equivalent length of cable 16 is released from the second side of the winch drum 13. When the rack assemblies 20 reach the ends of the longitudinal channel 18, the first side of the winch drum 13 rotates in the opposed direction or second direction. When this occurs, the second side of the winch drum 13 releases a length of cable 16 to effect movement of the rack assembly 20 in the second direction and at the same time draws in an equivalent length of cable 16 on the first side of the winch drum 13. The cable drawn onto the first side of the winch drum is creating the pulling force to move the rack assembly. Although the cable is continuous and the drum both pulls on and releases cable at the same time, the cable drawn onto the first side of the winch drum does the work. The cable is made of wire rope, although it is envisaged that other types of cables capable of performing the same function can be used. [0030] Utilizing a continuous length of cable 16 in conjunction with the rotating winch drum 13 for use in a floor recovery system 10 accords several advantages. Firstly, it allows the rack assemblies 20 to be more compact. Using a continuous length of cable 16 together with the winch drum 13 enables a longer stroke length which allows the rack assemblies 20 to be made shorter and thereby allows them to traverse the entire length of the longitudinal channel 18. This also allows the rack assemblies 20 to be easily removable from the floor recovery system 10 for servicing and maintenance. Large portions of the perforated floor grating need not be removed to reach the compact rack assembly. Secondly, a compact rack assembly means less wear and tear as it is subjected to less impact from rebounding abrasives and therefore longer life-span. Thirdly, a compact rack assembly means less material to manufacture and therefore less costs are incurred.

[0031] Figure 3 shows a side view of the floor recovery system 10. When in use, the cable 16 in motion effects the movement of the rack assembly 20 from one end of the longitudinal channel to the other end where a collector 15 is located to receive the abrasives. The collector 15 can be a belt conveyor or a cross screw conveyor which transports the abrasives to a bucket elevator for further processing. Although the collector 15 is shown at one end of the floor recovery system, it is envisaged that the location of the collector 15 can be placed in any suitable location along the floor recovery system 10. The belt conveyor or screw conveyor transports the abrasives along the width of the floor of the recovery system.

[0032] Figure 4 is a side view of a rack assembly 20 affixed to the cable 16 on the longitudinal channel 18. The rack assembly 20 is approximately 600mm long. It is also approximately 100mm narrower in width than the longitudinal channel 18. The rack assembly 20 includes a pivoting blade 21 spanning the approximately the width of the longitudinal channel 18 (See Figure 6). The pivoting blade 21 is pivotally mounted on the rack assembly and is movable between a first position and a second position. The first position of the pivoting blade allows the pivoting blade to contact the floor or approximately 10mm above the floor. The pivoting blade is set approximately 10mm above the floor of the longitudinal channel because this allows a layer of 10mm thick abrasive to build up on the floor and become a self replacing protective wear plate so as to push the abrasives along the length of the longitudinal channel in a direction towards the collector 15. The first position of the pivoting blade 21 occurs when the rack assembly is in a forward motion. The second position of the pivoting blade allows the pivoting blade to pivot away or to be raised from the floor of the longitudinal channel such that it is no longer in contact with the abrasives on the floor of the longitudinal channel. When this occurs, the movement of the rack assembly is in a backwards motion and the direction of travel of the rack assembly is reversed from when the pivoting blade is in the first position. The pivoting blade 21 is raised above the abrasives by approximately 10-20mm.

[0033] Figure 5 is an elevation view of the rack assembly 20 on one of the channels 18. Each channel 18 includes rail guides 22 running on each side of the channel 18. The rack assembly 20 includes support members 23 that can be slidably mounted on the rail guides. Two support members on each side of the rack assembly are configured for mounting on the rail guides. The support members 23 enable the rack assembly 20 to be suspended above the floor of the channel 18 and to allow the pivoting blade 21 to pivot between the first and second positions. The support member 23 is made of polyurethane and includes VEE slide blocks which allows it to be slidably mounted on the rail guides. The pivoting blade 21 is pivotally mounted to the rack assembly by a pivot bearing (not shown) on each side of the blade to allow the blade to pivot freely.

[0034] Figure 6 is a plan view of the rack assembly when mounted on the rail guides of one of the channels 18. The rack assembly 20 is affixed to the cable 16 at approximately midway of the rack assembly. The support members 23 are located on each side of the rack assembly 20 and configured such that the rack assembly is slidably mounted on the rail guides in a secure position. The pivoting blade 21 includes a yoke 24 for affixing to the cable 16. A clamping member 25 clamps the yoke securely onto the cable 16. When the cable 16 initiates movement in a first direction by the rotating winch drum 13, the rack assembly 20 moves together with the cable 16 in a forward direction. The motion of the cable 16 momentarily pulls on the yoke to enable the pivoting blade 21 to pivot to its first position in contact with the floor so as to push the abrasives along the channel 18. When the rack assembly 20 reaches the end of the channel 18, the winch drum reverses its direction of rotation so as to enable the cable 16 to reverse its direction. When the cable 16 reverses its direction of motion, the cable momentarily pulls on the yoke to enable the pivoting blade 21 to pivot to its second position such that the pivoting blade 21 is raised above the floor of the channel 18. [0035] While embodiments of the invention have been described and illustrated, it will be understood by those skilled in the technology concerned that many variations or modifications in details of design or construction may be made without departing from the invention.