GB1477112A - Portable apparatus for blast cleaning - Google Patents

Abstract

1477112 Blasting WHEELABRATORFRYE Inc 7 Feb 1975 [10 Oct 1974 11 Nov 1974] 43973/76 Divided out of 1477111 Heading B3D A portable apparatus for blast-cleaning a surface, such as the hull of a ship or a storage tank comprises means 116, Fig. 2 for upwardly projecting particulate material onto a surface along a first defined passage with sufficient kinetic energy to rebound therefrom along a a second defined passage, a hopper 118 disposed above the means 116 for receiving the rebounded particulate material so that the material faces through the hopper by force of gravity back to the means 116, means for substantially separating debris from the particulate material prior to the entry of the material into the hopper, and means for removing residual kinetic energy from the particulate material and debris prior to entry into the separating means. As described, the apparatus has at least one, and preferably two, centrifugal blasting wheels 116 supplied with particulate material from a hopper 118 controlled by a slide valve 126 to throw the material vertically upward against a surface to be cleaned. As the spent particulate material rebounds from the surface it, and residues from the surface are deflected by a transverse air-flow from an inlet 134 into a rebound chamber 132, the air flow also acting to cool the blast area. The particulate material and residue is directed by a sloping surface 144 to a set of adjustable ledges 138, 140, 142. The material initially builds up on the ledges until it overflows and then falls as an evenly distributed curtain. A cross air flow from an inlet plenum 148 passes across the curtain and carries dust and fine particles to an exhaust plenum 150, exhaust fan 154 and dust collector 156, the heavier particles falling into the hopper for re-use. The conduit 124 from the hopper to the wheels 116 has quick-release connector rings 128 for providing access to the wheels in the event of jamming or for servicing. In order to prevent material, such as paint, removed from the surface being treated, building up on the impeller 170, Fig. 3, of the blasting wheel, a scraper block 174 may be secured to the conduit 124 and extend within the end 171 of the impeller. The apparatus has a seal 112 for engagement with the surface to be treated and, in order to ensure correct engagement, a positioning sensor is provided having contact shoes which engage the surface and are carried by arms movable about pivots to actuate slide potentiometers controlling hydraulic valves for operating a positioning unit for the apparatus. In another embodiment, a blasting head structure 212, Fig. 6 and 7, can be attached to either a side cleaning module 210 and the particulate material is thrown upwardly at an inclined angle for treating a vertical surface, or to an upblast module 214 and the particulate material is thrown vertically for treating the underneath of a horizontal surface.