GB811092A - Arrangement for cutting off the supply of the material on disturbances occurring in pneumatic conveying plants for grain or similar materials - Google Patents

Abstract

811,092. Pneumatic conveyers. SVENSKA FLAKTFABRIKEN A.B. June 19, 1957 [June 20, 1956], No. 19311/57. Class 78 (1). In a conveying plant in which the material is drawn into the plant through a nozzle consisting of two concentric tubes and equipped with throttling means for automatically governing the air supply in accordance with pressure variations occurring on the suction side of the system, an extension tube is connected to the lower end of the outer tube of the suction nozzle and projects to such an extent below the inner tube of the nozzle that when the air supply is at a maximum, the sub-pressure at the mouth of the tube will be insufficient to lift the material through the extension tube. The lower end 1, Fig. 1, of the conduit 32, Fig. 3, is surrounded by a concentric tube 2, the upper part of which is connected to a chamber 3 and the lower part of which has a tubular extension 12. Inlets 4, 9 for air are provided in the wall of the chamber. The amount of air admitted through the aperture 4 is controlled by a damper 5 which is pivoted at 5b and connected by a rod 8 to a membrane 7. The membrane separates the chamber 3 from a space 13 which is connected with the suction side of a fan 35 by a pipe 38a. A spring 6 tends to hold the damper 5 in open position. The area of the inlet 9 is varied by moving a sliding door 10. The tube 12 projects to such an extent below the mouth 1a of the conduit 1, that when the air supply is at a maximum, the sub-pressure at the mouth 1a is not sufficient to lift the material through the tube 12. The conduit 32 is connected to a separator 33 from which the air passes through a pipe 34 to the fan 35 and the grain passes through a bladed rotor 37 into a pipe 36 leading from the fan 35. The pipe 38a contains an electromagnetic valve 39, the controlling circuit of which contains one or more contact breaking means 43. The means shown is actuated by a volumetric flow governor 40 and a discharge controller 44. After the quantity of air necessary for the calculated capacity has been adjusted by moving the damper 10, the inflow of material is regulated by the damper 5. When the quantity of transporting air falls below a value sufficient for the efficient operation of the system, the governor 40 moves to a position in which it actuates the contactbreaker 43 through the lever 42 to close the valve 39. As a result of this the damper 5 will descend to a position in which the aperture 4 is open fully and no material will be sucked up the tube 12. Specification 700,742, [Group XXIX], is referred to.