Abstract: The invention concerns an apparatus and a process for the periodic cleaning out of the pipes of heat exchangers to remove deposits of finely-divided solids, in particular carbon black or pyrogenically produced inorganic oxides. The apparatus consists of jet nozzles, which are arranged at a spacing above the gas entry openings of the pipes and are supplied with a cleaning gas, having excess pressure with respect to the process gas, via ducts provided with shut-off elements. The jet nozzles can be stationary or arranged for displacement along a row of the heat exchanger pipes. The process envisages flushing the pipes to be cleaned preferably in succession during operation of the heat exchanger, periodically, with a gas stream released with an impact and maintained for a short time at high speed.

Abstract: An apparatus is provided for removal of grit from a finely dispersed solid containing gas stream serving for the pneumatic conveyance of this material, the apparatus comprising a closed separator housing having a funnel shaped lower portion, a supply tube for the conveying gas stream opening laterally in the upper part of the housing, an outlet tube (in a given case connected to a vacuum source) for purified finely dispersed solid disposed opposite the supply tube in the upper part of the housing, a vertically disposed connecting piece between the lower end of the funnel shaped lower portion and a discharge valve, an axially disposed cap shaped displacement member open at its lower end in said connecting piece and of lesser diameter whereby an annular gap is formed between the displacement member and the connecting piece and a supply tube for furnishing a secondary gas stream to the interior of said displacement member.