Patent GB-892772-A (GB)
Title: Particle throwing apparatus
IPC: B24C5/06
Filed: 1959-08-06
Abstract: 892,772. Abrasive blasting. PANGBORN CORPORATION. Aug. 6, 1959 [Aug. 6, 1958], No. 26887/59. Class 60. A particle throwing apparatus comprises a rotor mounted on a spindle for rotation in a housing, the rotor having throwing vanes adapted to throw particles outwardly of the housing when such particles are fed to the vanes, and a sealing ring secured to the housing adjacent to the outer peripheral portion of a flange provided on the spindle adjacent to the rotor, the flange having a peripheral lip projecting into closely spaced co-operation with the outer surface of the sealing ring. A spindle 10 is journalled in a tubular support 12 by bearings and rotated by means of a pulley on one end. At its other end the spindle is provided with a flange 16, shrunk, keyed or otherwise securely held in place, to the front face of which is secured, by bolts 20, a rotor 18. On the front face 22 of the rotor are mounted vane holders 21, each holder being engaged by a bolt 24 and locking pins 26, 28 and having a generally triangular brace 30. Enlarged bosses 31, 32, 33 are provided for the anchorage members. An aperture, 36 in each holder receives an ear 38 forming part of each throwing vane 40. The vane is clamped against the supporting face of the holder by a spring 44 secured to the back of the holder by screw 46. The ear has a lobe 48 received in a notch 52 formed in the outer wall of the aperture, and a second lobe 54 forming a pocket 56 in which the spring 44 fits. A central impeller 62 secured co-axially to the rotor by bolt 64 has radial blades 66. An adjustable impeller case 70, having a rectangular, circular or triangular slot 79, has its outer edge 72 outwardly flanged and resting against a housing 75 secured to the spindle support 12 as by bolts and completely surrounding the assembly except for an opening 77 through which a portion of the wheel projects and through which the particles are projected. A deflector ring 60 fitted against the face 22 of the rotor causes any abrasive escaping through the rotor end of the case to be deflected on to the throwing face of the vanes so preventing excessive wear on the rotor face 22; the deflector ring can be held in place by the vanes and/or the holders, which may be notched to receive it. The housing has front wall 81, back wall 82, top wall 83 and side walls 84, 85. Front wall 81 is shaped to fit under as well as around the impeller case flange 72, as by cupping it or by welding on a ring 86. An opening in the housing through which the impeller case penetrates also receives a spout 88 secured against the outer surface of flange 72 and having a flange 90 covering and sealing the entire case opening. A sealing ring 92 is interposed between flanges 72, 90. The spout is held in place by a clamp having a latch dog 94 carried by a block 96 pivotally held by a pin 98 between links 99, 100 pivotally mounted on front housing wall 81 by a mounting ring 102 and mounting pins 103, 104. The block 96 has an integrally formed handle 106. The latch dog 94 which may be rubber engages a clamping socket 108 in the spout. When the clamp is released, the spout can be pulled out slightly and the impeller case shifted in rotary position to change the direction of its particle stream discharged from the wheel; re-clamping is then effected. A supply shoot is connected to the spout by a funnel segment 110 or a container with a supply of particles is directly mounted on the spout. The inside of the housing is lined with wear plates. A rear liner comprises an annular central section 112 secured by screws to the rear wall 82 and a section 116 held against the rear wall 82 by spacer and bolt combinations 118. For ease in assembling, section 112 is made in two segments and section 116 in four segments. The front wall 81 is protected by a liner 120, in two or four segments, secured to the wall. The front and rear liners are connected by end liner plates 122, 123 held in place in spaced arrangement with respect to the side walls 84, 85 by lugs 126 fastened to the bottom edges of the front and rear liners. Extensions 128 secured, e.g. by welding, to the end liners locate them with respect to the front and rear walls and form a labyrinth seal with offset portions of the front and rear liners to protect the housing from flying particles. For access to the housing interior the top wall 83 is removable. It comprises a lower sheet 131 fitting between the tops of the other walls and a larger upper sheet 132 having slots 134 receiving locking bolts 136 pivoted on the housing at 138 and carrying nuts 140. A gasket ring 142 is applied around the margin of lower sheet 131. A cover 144 is placed over the opening defined by the front, rear and side liners. The central section 112 of the rear liner has a cylindrical baffle flange 150 spaced from the periphery of the rotor 18 to minimise the entry of particles into the space between the rotor and the rear liner. Tapered escape openings 152 may be provided in the baffle at or near its lowermost portion. A sealing ring 156 secured to the housing extends in close relationship (not more than about 1/16 inch away) with the flange 16 which has a lip 158 overlapping the margin of the sealing ring. The sealing ring has a groove 160. Relief openings 162 are provided in the support 12 for escape of particles which get past the seal. A second sealing ring 166 is secured to the support 12 and has a lip 170 in close mating engagement with a groove 172 in the rear face of the flange 16 it also has a cylindrical portion 168, with grease grooves, 176, closely engaged with a collar 174 mounted on the spindle 10. The drive end of the spindle 10, where it emerges from the support 12, can be sealed against penetration of particles by a duplicate of sealing ring 166. The entire apparatus can be mounted at any desired location by means of a base plate 180 secured to the housing by welded members 182. The base plate may also be secured to the remote end of the support 12. In a modification, Fig. 5, vane holders 220 are integral with the rotor assembly 218. The vanes comprise a wear-resisting channel 242 welded, brazed or cemented to a back 240. Additional wear-resistant material 244 is used to protect the area between the inside flange of the channel 242 and the face of the rotor assembly 218. In a further modification, a rotor assembly is integrally cast with vane portions. The particleengaging surface of the vane portions may be provided with an abrasion-resistant covering, e.g. by projecting a mixture of tungsten carbide particles and a bonding powder of metallic iron, cobalt, nickel, titanium or the like through an oxyhydrogen or oxyacetylene flame on to the surface. After the coating has been applied it is heated by a torch or in a furnace to 1900‹F. for 5-30 minutes. Other carbides such as boron carbide, zirconium carbide and tantalum carbide may be used. Alternatively, the coating may be of alumina, zirconia, thoria, &c., applied by sintering a layer of such particles in place. Instead of spraying the coating, a layer may be preformed by sintering carbide particles with finely divided bonding metal, the layer being then secured in position by a thin layer of epoxy resin. Boron carbide, silicon carbide and other hard materials may be sintered together without a binder or with very little binder to make facing members cemented or mechanically secured in place as by wedging or bolting; the preformed coating may be sintered in place by a second sintering operation. Alternatively the coating may be welded or brazed in place. In a further modification, the vanes are made integral with the vane holders, and an abrasiveresistant coating or insert is provided in those areas with which the particles thrown by the apparatus come in most violent contact. Other parts of the apparatus may also have abrasion-resistant coatings, e.g. the surface 22 of the rotor 18 and the inside surfaces of liners 112, 116, 120, 122, 123, 144. The walls of the housing may be so faced and the liners are then partially or completely omitted. The spout 88, impeller 62, impeller case 70 and deflector ring 60 may have abrasion-resistant coatings or may be made wholly of abrasion-resistant material. In a modification, Figs. 8, 9, 10, the rotor 518 has in its front face radial grooves 519 each slidably receiving the foot 541 of a vane 540. A tapering face 543 joins the foot with the rear of the main vane body, the front of which is channelled. The rear face of the vane is generally recessed at 544 and carries a rearwardly projecting locking ear 538 having a tapering face 539. Vane holders 521 have on their front faces tapering surfaces 545, 546 engaging the vane surfaces 543, 539. The vane is locked by a pin 528 inserted in a socket in the rotor and engaging the wall of a notch in the foot of the vane. The engagement between surfaces 539, 546 is tapered in the radial direction. The ear 538 may extend the complete length of the vane or can be divided into separate parts. The feet 541 can also be subdivided. Each foot may have only a few separated locating pads, the remainder being relieved. The vane supporting surfaces of the vane holders may be recessed. The rear liner 612, made of a single section or with radial segments, can be fitted directly against the internal face of the housing but preferably engagement is limited to a small portion of the liner surface such as the central edge 613. Baffle flange 150 is integral with the liner and tapering openings 625 are provided round the complete periphery of the baffle where it joins the liner. Front liner 620 is mounted directly against the face of the housing. A cover liner 144 is rested between the tops of the front and rear liners the upper edges 622 of which are offset towards each other to accommodate the skirt of the cover liner. End liner plates 628, 629 have flanges 630 projecting into spaces left by offsets 626 on the front and rear