Cartridge mount for powder collector

Abstract: A powder collector has at least one hollow cartridge (20), open at one end and closed at the other, disposed between two parallel walls (15,16) of the collector. The open end of each cartridge overlies an opening (17) formed in one of the walls (15) and a gasket is provided around each opening. Compression means (55,60,65) mounted in the wall opposite the opening (17) presses the cartridge (20) against the gasket, so providing an effective seal around the open end of the cartridge. Three triangularly positioned rods (30,31) extend between the walls to form a cage to retain the cartridge.

Description: This invention relates to a powder collector for a powder booth, and more particularly, the invention is directed to the sealed mounting of cartridges in the collector. The powder booth is well known, and one form of it is described in US-A-4 723 505. The powder booth has a chamber through which an object to be finished with powder is conveyed. Electrostatic guns fire powder into the atmosphere surrounding the object to be finished, and much of the powder adheres to that object. The remainder of the powder is conveyed by airflow and gravity through the powder booth to a collector. Collectors generally have a filter medium through which the air from the powder booth is drawn, the powder being arrested by the medium. Reverse pulses are from time to time introduced into the reverse side of the medium to knock the powder off the medium, thereby preventing its being clogged. The thus filtered air is then directed through a final filter and into the plant atmosphere. The final filter is provided to assure the cleanliness of the air that is introduced into the plant. In the powder booth of US-A-4 723 505, the powder collector consists of a housing that is mounted on castered wheels so that it can be rolled into and out of position adjacent the powder booth, thereby permitting the quick changeover from one colour powder to another. The housing has opposed walls with opposed openings in the walls. Extending across the housing is a triangular tower structure formed of three triangularly-spaced rods, the rods being cantilevered from one end of the housing adjacent the air outlet opening. The free end of the tower has a plate and a bolt projecting from the plate, the plate and bolt being located adjacent the opposite opening. A hollow cylindrical cartridge is mounted in the collector adjacent each opening by sliding it over the tower structure. A plate is bolted onto the projecting nut with the bolt tightening the plate against the cartridge and against the wall of the housing. Gaskets are provided at the ends of the cartridge, and a gasket between the plate and the housing wall is provided in order to seal the cartridge within the collector. The structure described normally provides a satisfactory seal. However, when a collector is transported from the factory to the finisher, tightened bolts become loosened and leakage can occur. Further, if the housing, which is formed of sheet metal, is manufactured slightly out of true so that the opposed walls are not precisely parallel to one another, the clamping of gaskets is not uniform and leakage can occur. The consequence of leakage is that the powder that leaks past the cartridge flows to the final filter and rapidly builds upon the final filter. When the final filter plugs up due to the flow of excess powder onto it, air ceases to flow from the spray chamber through the collector and the recycle system totally breaks down. If leakage occurs, it normally requires a mechanic to make the adjustments necessary to stop the leakage. It is a general objective of the present invention to provide a collector for a powder booth wherein the cartridge is mounted in such a rigid support system that a single bolt tightening the cartridge against a single gasket provides a simple and reliable seal. A powder collector in accordance with the invention comprises at least one hollow cartridge filter disposed between two opposing walls, each cartridge being open at one end and closed at the other end, one of the walls having an opening or openings, each opening being aligned with a cartridge filter so that the open end of each cartridge filter overlies an opening, and a gasket surrounding each opening to form a seal between the wall and each cartridge filter characterised in that at least one pair of parallel rods underlying each cartridge filter extends between the two walls, each pair of rods providing a support for a cartridge filter, and in that means engageable with the closed end of the cartridge filter are provided for compressing the gasket between the wall and the open end of the cartridge filter. Preferably the two spaced parallel rods are welded between the opposed walls, the two rods providing a support or saddle onto which the cartridge is placed. Once the cartridge is in place, a third rod is bolted across the top of the cartridge so that the cartridge is surrounded by a preferably equiangular configuration of rods secured to the opposed walls. Preferably the compressing means is a bolt which is threaded into the closed wall and is engageable with the closed end of a cartridge. When the bolt is tightened to drive its inner end inwardly against the cartridge, the opposite end of the cartridge, carrying a gasket, is forced against the opposed wall around the discharge opening therein. A plate may be mounted on the inner end of the bolt to engage the closed end of the cartridge. With the foregoing mounting of a cartridge in the collector, the possibility of leakage around the open end of the cartridge is eliminated. Should the clamping bolt become loosened, it is a very simple matter to tighten it, thereby eliminating any leakage problem. In addition to minimizing the possibility of leakage, the present invention facilitates installation, increases structural integrity, reduces the cost of the collector, and in simplifying the collector improves it aesthetically. In another embodiment of the invention the compressing means may comprise a rod which is slidable in the second wall and a spring to urge the rod against the closed end of this cartridge. The invention will now be described further by way of example with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a collector in accordance with the present invention; Fig. 2 is a side elevational view of the collector; Fig. 3 is a cross-sectional view taken along lines 3-3 of Fig. 2; Fig. 4 is an enlarged fragmentary cross-sectional view taken along lines 4-4 of Fig. 3; Fig. 5 is a fragmentary elevational view of an alternative embodiment. Referring to Fig. 1, a powder collector is shown generally at 10 and includes a housing 11 with side walls 15 and 16. Side wall 15 has discharge openings 17 and the opposed wall 16 is closed. Cartridges 20 are mounted in the collector between the walls 15 and 16 and are preferably formed in two sections. Section 21 has a closed end cap 22 and an open end 23. The adjacent cartridge section has two open ends 26. A circular gasket is placed between the two sections 21 and 25, and a gasket is placed between the open end 26 and the wall 15 so as to seal the cartridge around the opening 17. The housing 11 has an open top 28 that may be clamped snugly against an opening in a spray chamber where product is sprayed with powder. Air laden with excess powder flows through the open top 28 of the collector and against the cartridges. The cartridges arrest the flow of powder while the thus cleaned air passes through the openings 17 and onto a final filter, not shown. See US-A-4 723 505, the disclosure for which is specifically incorporated herein for reference, for a description of the complete powder booth. Referring to Figs. 2 through 4, the manner in which the cartridges are supported and sealed in the housing is disclosed. For each cartridge a pair of spaced parallel rods 30 extend between the two walls 15 and 16 to form a saddle or support for the cartridge. The rods 30 are preferably welded permanently into place between the two walls 15 and 16. A third rod 31 has a head on one end and is threaded on the other end so that it can be removably mounted across the span between the two walls 15 and 16. The rods surround the opening 17 so that when the cartridge is in position surrounded by the rods, the open end of each cartridge is aligned with a respective opening 17. The cartridge 20 is an elongated hollow member made principally of filter material 37. As shown in Fig. 4, the open end of the cartridge is provided with a ring-shaped cap 35, presenting an opening 36 through which air can flow. The opposite end of the cartridge has a closed end cap 22, the end cap 22 having a central recess 41 of about 8" (20 cm) in diameter. A ring-shaped gasket of rectangular cross-section is adhesively-secured to the open end cap 35. The gasket is about 1" (2.5 cm) across and ½" (1.3 cm) thick and has an exposed sawtooth surface 43 to provide sealing points. The gasket may be made of silicone rubber of about 80 durometer. Identical gaskets are provided between the cartridge sections 21 and 25 and the cartridge 25 and the housing wall 15. In one embodiment of the compressing means, a torque nut 50 is welded to the wall 16 around an opening 51 in the wall. A threaded rod 55 is threaded into the torque nut 50 and has a head 56 provided at one end for rotating the rod in order to clamp the cartridges. The opposite end of the rod is rotatably mounted to a compression plate 60 which is slightly less than 8" (20 cm) in diameter so that it seats in the recess 41 of the end cap 22. In operation, the cartridges, with closed end caps 22, are placed on the lower rods 30 with the closed end caps adjacent the wall 16. Cartridge sections 25 having open ends are placed on the rods 30 with the gasket end of the cartridge section being against the wall 15 so that the gasket surrounds the opening 17. The rods 31 are inserted and secured between the two walls 15 and 16. Thus, the cartridges are securely mounted in a rugged cage formed by the walls 15, 16 and the rods 30 and 31. Each threaded rod 55 is rotated inwardly, thereby positioning the compression plate 60 against the end cap 22 to compress the gaskets and to securely seal the cartridge sections against leakage from between the wall of the collector housing and the end of the cartridge. As shown in Fig. 5, the compression sealing means may be a spring-loaded clamping plate instead of the threaded rod 55. The clamping plate 60 is mounted on a smooth rod 65. A compression spring is mounted between wall 16 and plate 60 to urge the plate against the cartridge. The rod carries a transverse pin 66 which can pass through a slot 67 in wall 16. To install a cartridge, firstly the rod 65 is withdrawn by pulling on handle 68 until the pin 66 passes through slot 67. The handle is then twisted to misalign pin 66 with respect to slot 67, thereby holding the rod in its withdrawn position. The cartridge sections 21,25 are inserted and the rod is then returned to its original position. With this embodiment, the spring pressure on the cartridge 20 is always uniform and does not depend on the degree to which a screw is tightened.

Claims: A powder collector comprising at least one hollow cartridge filter disposed between two opposing walls, each cartridge being open at one end and closed at the other end, one of the walls having an opening or openings, each opening being aligned with a cartridge filter so that the open end of each cartridge filter overlies an opening, and a gasket surrounding each opening to form a seal between the wall and each cartridge filter characterised in that at least one pair of parallel rods (30) underlying each cartridge filter (20) extends between the two walls (15,16), each pair of rods (30) providing a support for a cartridge filter (20), and in that means (55,60,65) engageable with the closed end of the cartridge filter (20) are provided for compressing the gasket between the wall (15) and the open end of the cartridge filter (20). A powder collector as claimed in Claim 1 characterised in that at least one third rod (31) extends between the walls (15,16) to provide a rigid cage surrounding each cartridge filter (20), each third rod (31) being parallel to a pair of rods (30) and overlying a cartridge filter (20), the or each third rod (31) being removably bolted to the walls (15,16). A powder collector as claimed in Claim 1 or 2 in which the compressing means comprises a screw (55) threaded in the second (16) of the two walls and engageable with the closed end (22) of the cartridge filter. A powder collector as claimed in Claim 3 wherein a plate (6) is rotatably mounted on the inner end of the screw (55) and is engageable with the closed end (22) of the cartridge filter to move the cartridge filter (20) axially and to compress the gasket. A powder collector as claimed in Claim 1 or 2 in which the compressing means comprises a rod (65), slidable in the second (16) of the two walls, and a compression spring to urge the rod (65) against the closed end (22) of the cartridge filter. A powder collector as claimed in any preceding claim in which the cartridge filter (20) is formed from two separate end-to-end hollow members (21,25) and a gasket is provided between the hollow members. A powder collector as claimed in any preceding claim wherein the cartridge filter (20) is provided with a closed end cap (22) on one end and an open end cap (35) on the other. A powder collector as claimed in any preceding claim wherein the cartridge filter (20) is an elongated hollow member formed principally of filter material (37).

Inventors: MEYERS REUVEN I, MEYERS, REUVEN I.
Applicants: NORDSON CORP, NORDSON CORPORATION
Application year: 1989
Main classification: B01D46
IPC codes: B01D46