Patent GB-1256922-A (GB)
IPC: B08B9/087
Filed: 1969-01-13
Abstract: 1,256,922. Removing dust and like waste products in industrial processes. WHEELABRATOR CORP. 13 Jan., 1969 [6 Feb., 1968], No. 46245/69. Divided out of 1,256,921. Heading F4X. Means for interconnecting a vertically movable dust generator and a stationary dust collector in a manner to establish a substantially sealing relationship therebetween comprises: (i) a vertically disposed duct having an open side dimensioned to have a length corresponding to the vertical travel of the dust generator;  (ii) a belt of resilient material covering said open side without attachment thereto throughout the length corresponding to the vertical travel of the dust generator; (iii) a head box vertically movable with said dust generator and having an open side facing the open side of the duct, side walls of said head box being spaced to correspond with the open side of the duct and to receive the belt therein; (iv) deflector means within the head box over which the belt travels to deflect the belt in the direction away from the open side of the duct in at least a portion of the area covered by the head box; (v) conduit means communicating the interior of the head box with the dust generator; (vi) other conduit means communicating the interior of the duct with the dust collector; and (vii) means for generating subatmospheric conditions within the duct constantly to urge the belt into sealing engagement with the portion of the duct not covered by the head box. A machine for cleaning a ship's hull, or the walls of a large capacity storage tank, has a blasting head 10 carried by a frame 100 vertically movable, e.g. through a range of 30- 70 feet, on a tower 90 which is normally stationary while the blasting head is in operation, but is capable of being moved intermittently to a new position alongside the work surface by means of a barge, tracked vehicle &c. The blasting head 10 includes a blast chamber 12 within the base of which is a bladed wheel 16 for throwing abrasive, e.g. steel shot or grit. At its forward end the chamber has an opening 14; inner and outer resilient seals 22, 24, e.g. of polyurethane, extend continuously about the opening 14 and are secured to a flanged plate 20 secured to the edge of the opening. The seals are protected from thrown abrasive by a baffle plate 26 secured to the plate 20. Air inlet spaces, Fig. 5, encircling the upper end portion of the chamber communicate through openings 32 with the space between the seals whereby air flows into the space to cool the seals and to assist in the removal of abrasive from between the seals. Spent abrasive falls down through the space between the seals and a slot 36, through a slot 38 in the plate 20 at the base of the inner seal 22, or over the plate 26 and shed plates 40. An air inlet 42 is provided immediately below the shed plates 40 44, 46, 48 for the admission of air which passes upwardly about the inner ends of the shed plates .and through the descending spent abrasive to remove dust and fines and to cool the abrasive. Ducts 82 connect outlets 84 at the top of the blast chamber with a stationary dust collector 230 which maintains subatmospheric conditions within the blast chamber. A vertical rigid duct 232 of rectangular, triangular or polygonal section has an open side 234 covered by a flat belt 236 slightly longer and wider than the opening, the length of the latter corresponding to the vertical travel of the frame 100. The upper and lower ends of the belt are fixed to the duct. The belt is trained round rollers 252, 256, 254, Fig. 9, mounted within a box 240 mounted for vertical movement with the frame 100. The box has guide plates 258, 260 for the belt. The duct 82 is connected to an inlet opening 264 in a side wall (250) of the box; an outlet duct in a side wall of the duct 232 is connected to the dust collector.