Patent Application
20170361350
This application relates to a particulate spray system, and more particularly to a particulate spray system with a particulate spray booth having a sealed particulate spray device booth wall opening to increase the efficiency of the particulate spray system by requiring less energy to exhaust powder overspray.
The present disclosure relates to particulate spray systems having one or more particulate spray devices that spray particulate materials onto workpieces inside the spray booth of the particulate spray system, wherein at least some of the particulate material must be collected from the spray booth and recovered for reuse. The particular spray device could spray particular materials onto the workpiece, such as for sandblasting the workpiece, for example. In a particular preferred embodiment, the particulate spray device could spray powder coating material in a powder coating material spray booth.
Powder coating material booths typically include openings in the booth walls to allow for powder spray devices to pass through and into the interior of the booth. To collect the excess powder following coating of an article or during a color change procedure, suction means are typically used. However, the openings in the booth walls can be large to allow for manual or automatic spray coating devices, resulting in the escape of overspray powder and requiring a tremendous amount of energy to power the suction means. To address this issue, a solution is needed to seal the openings to prevent the escape of overspray powder and more efficiently create a vacuum condition within the booth. Accordingly, this seal solution will result in a decreased overall cost of use of the booth, whether the booth is used to spray powder coating material or particulate material such as sandblasting materials.
In one preferred embodiment, the particulate spray system is a powder coating material spray system having a powder coating spray device surrounded by a flexible boot element. In one aspect, a powder coating material spray system may include a booth comprising a ceiling, a floor, and side walls defining an interior of the booth, wherein the booth defines an opening from the interior of the booth to an exterior of the booth. The system may further include a powder spray device received through the opening, the powder spray device comprising a body and a nozzle through which powder coating material is sprayed into the interior of the booth, wherein the nozzle and at least part of the body are disposed in the interior of the booth. The system may further include a flexible boot element having a proximal end and a distal end opposite the proximal end, the proximal end attached to a periphery of the opening to form a first seal and the distal end attached to the at least part of the body of the powder spray device disposed in the interior of the booth to form a second seal.
In an aspect, the powder coating material spray system may further include a powder recovery system comprising an overspray intake communicating with the interior of the booth and a suction means for drawing overspray powder from the interior of the booth into the overspray intake. The powder spray device may be moved by a robotic arm situated on the exterior of the booth.
In an aspect, the boot element may form a conical shape tapering from a first diameter at the proximal end to a second diameter at the distal end, the first diameter being greater than the second diameter. For example, the first diameter may be at least twice the second diameter.
In another aspect, the first seal and the second seal may each be hermetic seals.
In an aspect, at least one of the proximal end and the distal end of the boot element may be configured to attach, respectively, to the periphery of the opening or the body of the powder spray device via a lever-operated clamp, an elastic band, a zipper, one or more clips, or a hook-and-loop system. In an aspect including a zipper, the boot element may comprise a flap covering the zipper.
In another aspect, the distal end of the boot element may be configured to attach to the body of the powder spray device via a rotatable bearing. In such an aspect, the nozzle may include an outlet through which the powder coating material is sprayed, the outlet configured as an elongate slit.
In yet another aspect, the boot element may comprise at least one of polyurethane, neoprene, silicone, and latex.
In another preferred embodiment, the particulate spray system is a system for spraying sandblasting materials onto a workpiece inside the booth. The spray device is surrounded by a flexible boot element. In one aspect, the spray system may include a booth comprising a ceiling, a floor, and side walls defining an interior of the booth, wherein the booth defines an opening from the interior of the booth to an exterior of the booth. The system may further include a spray device received through the opening, the spray device comprising a body and a nozzle through which particulate material is sprayed into the interior of the booth, wherein the nozzle and at least part of the body are disposed in the interior of the booth. The system may further include a flexible boot element having a proximal end and a distal end opposite the proximal end, the proximal end attached to a periphery of the opening to form a first seal and the distal end attached to the at least part of the body of the spray device disposed in the interior of the booth to form a second seal.
In an aspect, the spray system may further include a recovery system comprising an overspray intake communicating with the interior of the booth and a suction means for drawing particulate material that has already been sprayed from the spray device from the interior of the booth into the exhaust. The spray device may be moved by a robotic arm situated on the exterior of the booth.
The following detailed description is better understood when read in conjunction with the appended drawings. For the purposes of illustration, examples are shown in the drawings; however, the subject matter is not limited to the specific elements and instrumentalities disclosed. In the drawings:
Although this disclosure details a powder coating material spray booth, it is understood that the teachings below can be applied to other particulate material spraying systems, such as a system for spraying sandblasting materials onto workpieces within the booth, such as to remove coatings from the workpieces or clean them.
Disclosed herein are systems and apparatus for providing a flexible boot element for use in conjunction with a movable spray device of a substantially sealed powder spray booth. The boot element may be attached to both the spray device and a wall of the powder spray booth such that the boot element provides a seal between the interior of the powder spray booth and the exterior of the powder spray booth while still allowing sufficiently free movement of the spray device to execute its spray function. For example, the boot element may be configured as a generally conical formation in which the larger end of the boot element is sealed to the opening of the powder spray booth through which the spray device projects and the smaller end of the boot element is sealed to the spray device.
In some aspects, the ceiling, side walls 4, end walls 6, and/or floor 10 of the spray booth 2 may be made from a non-conducting material, such as plastic. By using plastic or other non-conductive material, the powder sprayed from the spray device 16, which in some applications may be electrostatically charged, will have a reduced tendency to adhere to the surfaces of the spray booth 2. Accordingly, the powder not adhering to the spray object (i.e., overspray powder) will fall under gravity and collect on the floor 10 or other lower portions of the spray booth 2. For durability, the floor 10 and/or surfaces on which an operator will walk may instead be made of stainless steel.
One or more openings 12 may be defined in the side wall 4 (or other surface defining the interior of the spray booth 2) to allow a respective spray device 16 to project into the interior of the spray booth 2. The spray device 16 may be controlled by a human operator (not shown) or by a robotic arm 14 (as shown in
The spray device 16, or portion thereof, projecting into the interior of the spray booth 2 is surrounded by a boot element 13 configured to attach to the spray device 16 and the periphery of the opening 12 to seal the interior of the spray booth 2. The seal provided by the boot element 13 may serve to prevent airborne overspray powder from exiting the interior of the spray booth 2 and potentially contaminating the exterior, the robotic arm 14, and/or human operators. Further, the seal provided by the boot element 13 may also facilitate a suction and/or airflow created by a powder recovery system 34. The spray device 16 and the boot element 13 will be described in additional detail with reference to
With additional attention to
The powder recovery system 34 may include a cyclone separator 36 that is connected to the duct 20. In the cyclone separator 36, the overspray powder is separated from the air-powder mixture drawn from the spray booth 2 via the duct 20. Under the influence of centrifugal and gravitational forces, the overspray powder falls to the bottom of the cyclone separator 36 where it may be collected in a container for re-use. The exhaust air from the cyclone separator 36 which, during normal operation of the spray booth 2 contains only a small amount of overspray powder, passes through a connector pipe 38 to a powder filter unit 40, which is sometimes called an after filter. The powder filter unit 40 includes therein one or more filter elements, such as one or more filter cartridges 42, which filter out the remaining overspray powder in the exhaust air from the cyclone separator 36. The cleaned exhaust air is then drawn out of the filter unit 40 and discharged into the atmosphere by a fan 44 mounted at the top of the filter unit 40. Powder collected in the filter unit 40 may also be collected for re-use.
It will be appreciated that the action of the fan 44 provides the current of exhaust air within the spray booth 2 to draw the overspray powder into the overspray intake 18. The larger the area of any openings in the spray booth 2 (e.g., an unsealed opening 12 for the spray device 16, an opening of a conveyor slot, etc.), the greater the size of the fan 44 required to pull sufficient air through those openings to keep the overspray powder within the spray booth 2 and collect it in the powder recovery system 34. In determining the size of the fan 44, the width and length of the conveyor slot at the top of the spray booth 2, the size of the openings at the entrance and exit of the spray booth 2 and/or the size of all openings in the sidewalls of the booth, such as the openings 12 for the spray guns 16 to project within the spray booth 2, must all be considered in order to achieve the desired CFM (cubic feet per minute) air flow rate into the spray booth 2 through these openings. By using the boot element 13 to provide a seal to the opening 12 through which the spray device 16 is inserted into the spray booth 2, this large opening into the spray booth 2 can be removed from the calculation of the CFM air flow rate required to pull enough air into the spray booth 2 to keep the overspray powder in the spray booth 2 and collect overspray powder in the powder recovery system 34, resulting in a lower required CFM air flow rate than would be the case if the opening 12 were not sealed. This lower CFM air flow rate translates into a smaller fan 44 that can be provided to maintain the necessary airflow through all the spray booth openings to maintain overspray powder within the spray booth 2 and collect it in the powder recovery system 34. Accordingly, by reducing the size of the fan 44 in accordance with the teaching of this disclosure, energy costs can also be reduced as well as the cost of the fan 44.
Referring again to
A diverter plate 26 is positioned in the trough 24 at the end where the overspray intake 18 is located and extends from that end. The length of the diverter plate 26 is preferably equal to the distance from the end of the spray booth 2 to the center line of the first spray device 16 relative to that end of the trough 24, plus an offset. The offset may suitably be of the order of 200 mm. The diverter plate 26 is suitably spaced from the lower edges of the sloping portions 22 to define slots 27 therebetween. The diverter plate 26 is detachably supported on its underside by tabs (not shown) affixed to the lower edges of the sloping portions 22 and is mounted to the end wall 6 via one or more hinges 30 to allow it to be pivoted up and against the end wall 6. The diverter plate 26 is configured with a pattern of holes 28 therein. The holes 28 are elongate in the lengthwise direction of the diverter plate 26 and hence also the spray booth 2.
In use, one or more of the spray devices 16 are employed to apply powder to objects passing through the spray booth 2. Airborne overspray powder is extracted from the interior of the spray booth 2 on the current of exhaust air produced by the fan 44 of the powder recovery system 34 via the overspray intake 18 and duct 20. Overspray powder which falls out of the transport air provided by the powder recovery system 34 will be deposited on the floor 10 of the spray booth 2 and so on the sloping portions 22, the bottom of the trough 24, and the diverter plate 26. The flow of exhaust air caused by the powder recovery system 34 along the trough 24 will tend to draw deposited overspray powder on the upper surface of the diverter plate 26 down into the trough 24 there below either through the holes 28 or the slots 27 between the sloping portions 22 and the diverter plate 26.
The cleaning operation which is performed, such as when the color of the powder is to be changed, will now be described. The spray devices 16 are shut off and any access points to the interior of the spray booth are closed or sealed off. The diverter plate 26 is pivoted up against the adjacent end wall 6. An operator, preferably using an air hose, begins at the opposite end of the spray booth 2 from the duct 20 and moves along the spray booth 2 blowing the deposited overspray powder which remains therein from all wall and floor surfaces and the surfaces of the diverter plate 26, the duct 20, and the overspray intake 18. As the powder is blown off of the surfaces of the spray booth 2, it is drawn into the duct 20 by the current of exhaust air provided via the overspray intake 18.
With additional reference to
The boot element 13 depicted in
To provide a seal of the interior of the spray booth 2, the proximal end 14A of the boot element 13 is coupled with the periphery 29 of the opening 12 in a manner that provides a substantially air-tight seal with the periphery 29 of the opening 12. Advantageously, the proximal end 14A of the boot element 13 may also be releasably coupled with the periphery 29 of the opening 12 to facilitate easy decoupling of the boot element 13 and/or the spray device 16 with the side wall 4. Further, the distal end 14B of the boot element 13 is coupled with the spray device 16 to similarly provide a substantially air-tight seal with the spray device 16. The coupling of the distal end 14B of the boot element 13 and the spray device 16 may also be accomplished in a manner that allows easy release.
As shown in
As depicted in
Other than the aforementioned zipper 300 and clamp 400, other types of connectors for coupling the boot element 13 with the periphery 29 of the opening 12 and/or the spray device 16 include clips, snaps, elastic band, or hook-and-loop fasteners.
The boot element 13 may be formed of any flexible material suitable to allow movement of the spray device 16 and to provide a substantially air-tight seal of the interior of the spray booth 2 from the exterior of the spray booth 2. Exemplary materials of which the boot element 13 may be constructed include tight-woven fabric, polyurethane, neoprene, silicone, and/or latex.
In one aspect, depicted in
It will be apparent to those skilled in the art that various modifications and variations may be made without departing from the scope or spirit. Other implementations will be apparent to those skilled in the art from consideration of the specification and practice disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following claims.
