Patent GB-1298879-A (GB)
Title: Improvements in or relating to flow cleaners
Inventor: HOWE PETER WILLIAM HERBERT
IPC: F02M35/022
Filed: 1970-02-27
Abstract: 1298879 Centrifugal separators DEFENCE SECRETARY OF STATE FOR 19 April 1971 [27 Feb 1970] 9609/70 Heading B2P A fluid flow cleaner comprises a tube and at least one vane disposed within the tube and extending axially along the tube from, or from adjacent, its inlet, the or each vane being so convoluted about the tube axis that the angle thereof relative to the tube axis varies axially along the tube and an outwardly facing portion of a surface thereof is of approximately conical form with its axis substantially coincident with the tube axis, so as to impart swirling motion to fluid flowing through the tube, the or each vane also being arranged to initiate swirling at the periphery of the tube downstream of the tube inlet. In Fig. 2, four vanes 1-4 have their leading edges extending radially across one end of a tube 5 from the tube axis. The vanes are progressively twisted from their initial radial alignment, firstly clockwise relative to incident airflow (arrow A). After a short axial displacement the direction of twist is reversed and the blades are also bent to increase their curvature so as to present outward facing surfaces. In a two-vaned arrangement, each vane may have in developed form the configuration shown in Fig. 3, with leading and trailing edges 41 and 42 respectively. The vanes may have extended tips at their downstream ends Figs. 4 and 5 (not shown) which pass through discharge openings for separated foreign matter in the wall of the tube. In another arrangement, Figs. 6a-e (not shown), a single vane is rotated about a central axis with axial displacement to define a substantially conical form having a radially outer facing surface. The vane is provided at its upstream end with a solid portion or centrebody. In a further construction, Fig. 7, a vane increases in thickness from a leading edge 13 which extends radially from the axis of a tube 5 to the periphery of the tube at its upstream end. The vane has the form of an helix with variable pitch. The channels produced by the twisting of the vane have outward facing surfaces, while the outwardly tapered portion provides a "skid-path" whereby the particles contained in the fluid can be guided simultaneously axially and radially outwardly. In a cleaning apparatus, the end of the tube of the flow cleaner, downstream of the vane arrangement is closed and has a central outlet pipe for clean air extending into tube through the closed end. A side conduit adjacent the closed end leads impurities-laden air to a cyclone whose clean air outlet is connected to a widening end portion of the control outlet pipe. In another cleaning apparatus, Fig. 10, the downstream end of the tube 19 of the flow cleaner contains a central clean air outlet tube 20 defining therewith an annular space in which are spacedly mounted coned baffles 21, 22, which may alternatively be inclined in an upstream direction, defining a chamber 23 in which the outer layers of the impurities-laden air are toroidally circulated whereby separated clean air discharges via port 25 into the conduit 20 with the major portion of the clean air. In a panel arrangement of cleaner tubes, the baffles are helical, Fig. 12 shows a modification of Fig. 7 in which a hollow vane 26 replaces the solid one, cleaning of the fluid being effected both inside and outside the vane. A number of parallel tubes 5, Fig. 13, each containing a hollow vane 28 may be assembled to form a cleaning panel. Each tube contains a segmental flow diverter 2 for removal of dirty air. The diverters 29 in each group of three tubes are adjacent to each other with their outlets connected to a common exhaust tube 30 connected to a transverse duct 31. Clean air passes in the direction of the arrows K.