GB712067A - Improvements in or relating to apparatus for storing and transporting powdered material - Google Patents

Abstract

712,067. Pneumatic conveyers. BLAW KNOX. Ltd. Feb. 11, 1953 [Feb. 11, 1952], No. 3574/52. Class 78 (1) Apparatus for use in storing and transporting powdered material, e.g. cement, comprises a storage hopper 1 and an activator 4, communication between which is controlled by a valve 7, means for periodically admitting compressed air to the activator through a pipe 10 to blow its contents along a delivery pipe 9, a valve 61 for controlling the air supply, this valve and the valve 7 being interconnected and delay means being provided so that the apparatus changes automatically from filling to blowing after a predetermined period of delay between the termination of one operation and the commencement of the other. Low pressure air is blown through a porous plate 5 forming the inclined bottom of the hopper to assist the flow of material. With the parts in the position shown in Fig. 2 air from the high pressure supply pipe 15 passes through a shut-off valve 16 pipe 17, change-over valve 18 and pipe 19 to the upper end of the cylinder 13 and moves the piston 12 to the bottom of the cylinder. thus opening the valve 7. High pressure air passes also through pipes 31, 75 to a valve 68 and forces its piston 71 to the right to connect the pipe 69 supplying air to the porous plate 5 to a low pressure air supply pipe 62 through the pipe 67. High pressure air passes through a valve 32, pipe 33, needle valve 34 and pipe 35 to a reservoir 36 the pressure in which builds up while the activator is being filled with material. When this pressure is sufficient to overcome the spring 45, the valve 38 is operated to connect the pipe 28 with the high pressure air supply pipe 39. When this happens, the piston rod 22 of the valve 18 moves down to connect the pipe 19 to exhaust 30 and the pipe 20 to a supply of high pressure air. This downward movement of the rod 22 occurs because the upper piston 26 is of greater area than the lower piston 23 which also is under high pressure. The piston 12 moves up and the valve 7 closes. When the piston reaches the top of the cylinder, pressure builds up in the pipe 20 and actuates the valve 61. The opening of this valve causes low pressure air to be supplied to the actuator 4 through the pipe 10 to blow the material through the pipe 9. The increase in pressure in the pipe 10 forces the diaphragm 53 in the chamber 54 to the right to actuate the valve 32 to connect the pipe 27 to the pipe 31 and exhaust 30 and also to connect the pipe 33 to exhaust 58. The high pressure air in the reservoir 36 leaks away to exhaust through the needle valve 34 and pipe 33. When the pressure is lowered sufficiently, the spring 45 in the valve 38 returns the valve to the position shown and the pipe 28 is connected to exhaust 40. The valve 18, however, does not change over since the pipe 27 is connected to the exhaust 30. When all the material has been discharged, from the activator, the pressure in it falls and the diaphragm 53 is moved to the left by the spring 52 to the position shown. High pressure air is then delivered to the pipe 27 and the valve 13 returns to the position shown. The sequence of events is then repeated. The cylinder 76 of the shutoff valve 16 is connected by the pipe 82 to a valve 83 which is connected by a pipe 92 to the pipe 27. The piston rod 88 of the valve 83 is pivoted to a control lever 89 which is raised while the activator is blowing to stop the action of the apparatus.