GB1276478A - Tube cleaning pellet gun - Google Patents

Abstract

1276478 Cleaning pellet gun COMBUSTION ENG Inc 19 April 1971 [9 March 1970] 23419/71 Heading F2N A gun for firing compressible cleaning pellets 16, e.g. of felt, through a tube 12 to be cleaned comprises a barrel 18 having an axial bore 20 widened at its rear end 22. A plunger 36 is reciprocable within the bore and is driven by a fluid pressure piston 30 controlled by valve 66. A pellet introduced to the bore through aperture 42 is moved by the plunger so as to be leftwards of port 46 through which propellant, e.g. nitrogen gas, may be introduced. Cleaning solvent, e.g. acetone, may be injected into the pellet via port 138 prior to firing, and an interlock prevents acetone injection and firing unless the plunger is in its leftwards position. The pellet is conducted via flexible hose 54 to a tapered nozzle 60 wherein it is compressed to a diameter less than that of the tube to be cleaned so as to assist its introduction therein. Manual control valves 96, 116 and 142 are mounted adjacent the nozzle and connected to the operating valves via flexible hoses 94, 98, 120, 122 and 146. Control and operating system. (a) Plunger.-The plunger 36 is connected to piston 30 by rod 40. Compressed air is fed via filter 84 to port 68 of valve 66. The valve 66 is operated by a spring-returned pilot 92 which in its normal inoperative position holds the valve in such position as to feed air via port 72 to space 28 and connect port 70 to exhaust. The pilot 92 is operated by low pressure air fed via regulator 86 and line 98 to manual valve 96 and thence via line 94 to the pilot. (b) Propellant.-The propellant is controlled by valve 104 operated by spring-returned pilot 114 and is normally shut. Low pressure air from regulator 86 is fed via line 120 to manual valve 116 and thence via line 122 to pilot 114, a cut-off valve 118 being interposed in the line 120 to prevent operation of propellant valve 104 unless the piston is in its leftwards position. As an additional safeguard pressure in the control line 122 actuates, pilot valve 119 to exhaust line 94 and ensure the leftwards position of the plunger. (c) Cleaning fluid.-The cleaning fluid is dispensed via pilot operated valve 128 from a tank 126 pressurized with low pressure air from the regulator 86. The pilot 130 is operated by low pressure air fed from line 120 downstream of cut off valve 118 to prevent operation unless the plunger is in its leftward position. Control is via manual valve 142 and time controlled valve 148.