Patent GB-1383696-A (GB)
Title: Abrasive blasting unit
IPC: B24C3/06
Filed: 1972-04-10
Abstract: 1383696 Blasting CARBORUNDUM CO 10 April 1972 [12 April 1971] 16366/72 Heading B3D An abrasion blasting unit for blast cleaning the hull of a ship comprises a movable transporter 12, a vertical tower 16 mounted on the transporter, a work platform 18, elevating means connecting the platform to the tower for movement up and down the tower, a boom 20 pivotally connected to and extending ouwardly from the platform, an abrasive blast wheel 22 connected to the boom remote from the platform, and conveyer means incorporated in the boom for feeding abrasion particles to the blast wheel. The transporter has a front-wheel 24 and a pair of back wheels 26 equipped with pneumatic tyres having blow-out safety protection. All the wheels are steerable, the back wheels being locked together. Outriggers 30 are mounted on the transporter and are provided with hydraulically operated lifting pads 31 whereby the unit can be lifted so that the tyres disengage the ground. A car 14 is movable along the transporter by an hydraulic cylinder 58, the car being guided by rollers 32 engaging tracks 34. The tower 16 extends upwardly from the car and consists of a fixed, rectangular cross-sectioned column 36 on which is slidable a second column 38 movable by double rack-and-pinion mechanisms 40 driven by hydraulic cylinders 44. A sleeve 19 is telescopically mounted on the second column 38 and is movable thereon by cables or chains 50 entrained around pulleys 54 and driven by a motor 56. The platform 18 is carried by sleeve 19. The boom 20 consists of an upper member 82 connected to a lower member 86, the members being pivotally mounted on the platform by vertical hollow shafts 96, 98. The blast wheel assembly 22, Fig. 7, is mounted at the end of the upper member 82 and is mounted in a bearing 80 for adjustment about a vertical axis and is also adjustable about a horizontal axis. The wheel 66 is driven by a motor 68 and is enclosed in a shroud 70 having an opening 72 through which the blast passes to impinge on the ship's hull 11, the opening being provided with a seal 74 and sensors 76 which ensure that the assembly is pressed against the hull. Abrasive is fed along the upper member 82 by a screw conveyer 100 disposed therein, the abrasive passing down a hollow support shaft 78 to the wheel. Spent abrasive and debris falls from the bottom of the assembly 22 into a conical member 88 carried by the lower member 86 which has a screw conveyer therein for transporting the spent abrasive and debris to a hollow shaft 98, conveyer 104 elevator 116 and separator 108. Dust from the separator passes to a collector 112, which additionally has a flexible pipe 118 connected to a shroud 72. Abrasive particles from the separator are fed into a hopper 114 and an elevator for supply to the screw conveyer 100 in the upper member 82 of the boom. The car 14 cannot be moved unless the platform is in its lowest position, and the platform cannot be actuated unless the outriggers 30 have raised the wheels 24, 26 from the floor. The machine is controlled by an operator in a cab 62 on the platform so that the hull is cleaned in strips.