Patent GB-858725-A (GB)
Title: Method and apparatus for cleaning pipes by abrasive blast
Inventor: WOODCOCK FRED
IPC: B08B9/02
Filed: 1958-07-28
Abstract: 858,725. Abrasive blasting. RUSTON & HORNSBY Ltd. July 6, 1959 [July 28, 1958], No. 24158/58. Class 60. A method of cleaning the interior of pipes particularly small-bores pipes such as those used for conveying fuel or lubricating oil for internal - combustion engines, in which a stream of dessicated compressed air mixed with particulate abrasive is carried to one end of the pipes through a delivery conduit and through means for connecting the delivery conduit and pipes, the mixture passing through the pipes and through a return conduit or conduits connected to the further ends of the pipes by further connecting means and is carried to a separator located at the top of an abrasive container wherein re-usable particles fill and from whence waste is carried to a dust extractor is characterised in that the delivery conduit has a cross-sectional area less than the total cross-sectional area of the pipes being cleaned, and the return conduit or conduits possess a cross-sectional area not less than the total cross-sectional area of the pipes being cleaned. Compressed air passes through pipe 11, provided with a gravity liquid drain trap 12, to a drying vessel 14 containing moisture absorbing material 15 such as silica gel, and thence through a control web 17 to an abrasive reservoir 19. A main container 23 having abrasive 24 therein is connected to the reservoir 19 via a channel 25 having a valve seat 26 for a ball 27 normally supported by a cage 28. The reservoir 19 has an outlet conduit 29 carrying a control valve 30 and connected to a mixing chamber 22 to which air is supplied through branch pipe 21. The mixing chamber 22 is connected by a delivery conduit 32 to a manifold 33 to which are connected the pipes 34 to be cleaned and which are also connected to a further manifold 35 carrying return conduits 36 the outlets of which are directed over short gaps 38 into the container 23 via orifices 39. The container 23 has a baffle 40 and an outlet conduit 41 leading to a dust extractor 42. In operation, cock 17 is opened admitting air to reservoir 19 where it lifts the ball 27 onto its seating 26 thus pressing the reservoir 19 and preventing egress of pressurized air into the container 23 via channel 25. Valve 30 is then opened, allowing abrasive to flow from the reservoir 19 into the mixing chamber 22, the resulting mixture of air and abrasive passing through conduits 32 into the pipes 34 and onward through return conduits 36. That each individual pipe 34 is freely passing the mixture may be checked visually at the gaps 38. The operation of the dust extractor 42 effects an inflow of atmospheric air through the orifices 39 substantially preventing scattering of abrasive at the gaps 38. After sufficient time has been allowed for the cleaning, valve 30 is closed and after a further time during which air alone flows through the conduits and pipes to clear them of abrasive cock 17 is closed, whereupon reservoir 19 exhausts its pressure and ball 27 falls from its seating 26 into the cage 28 and the reservoir 19 is replenished with abrasive from the container 23. Should the ball 27 fail to leave its seating 26 it can be released by a tube 43 operated by a handle 44. The pipes 34 may be coiled or straight or of any shape. The return conduits 36 may be flexible, and a flexible section may be incorporated into delivery conduit 32 to facilitate the clearing of pipes of different shapes and varying lengths. A single pipe 34 or any convenient-number of pipes may be accommodated by modifications to the apparatus.