Patent GB-743410-A (GB)
Title: Improvements in or relating to apparatus for removing soot and other foreign matter from steam generating plant and other heat-exchangers
Inventor: SKIDMORE RONALD FRANCIS
IPC: F28G15/04
Filed: 1952-12-30
Abstract: 743,410. Soot-blowers. IVOR POWER SPECIALTY CO., Ltd. Dec. 30, 1953, [Dec. 30, 1952], No. 33009/52. Class 99(2). In a soot-blower wherein a blower tube for discharging steam, air or other fluid is advanced and retracted to and from the operative position and comprises outer and inner concentric tubes 11, 32 axially displaceable relatively to one another, the tube 11 being supported by a carriage 8 movable along a guide 1, the carriage carries power means, e.g. a reversible electric motor 51, which drives the carriage and is connected to mechanism arranged to impart an oscillating movement of predetermined amplitude to the tube 11. There is provided means for operating a valve 50 controlling the supply of steam to the blower tube and arranged for actuation by the translational movements of the carriage in such a manner that the valve is opened only when the discharge nozzle 14 of the tube 11 is within that zone of a boiler to be cleaned. As shown in Fig. 1, the carriage 8 and blower tube assembly is supported on an H-section, horizontal guide beam 1 secured to the wall 3 of the boiler and to a rear framework 4, the tube 11 passing through a wall box 9 having an annular collar 13 surrounding and sealing the tube, and the tube 32 being flanged to receive a conduit 49 connected to the valve 50 situated on top of the beam and ahead of the rear terminal position of the carriage. The tube 11 is supported adjacent the wall 3 by axially spaced pairs of rotatable rollers 28 mounted in members 25 secured to a sleeve rotatably mounted on ballbearings within a housing 18 carried on members 16 attached to the beam 1. Oscillation of blower tube. The tube 11 is connected by a flanged collar 31, Fig. 4, to a sleeve 35 journalled in bearings 36, 37 in the carriage housing 38, the sleeve being formed to provide an annular space surrounding the tube 32 and accommodating a cylindrical member 43 grooved internally to form a labyrinth and engaged by packing rings 44 maintained in position by a gland nut 45 screwed into the sleeve. Keyed to the sleeve 35 is a gear 68, Fig. 6, which meshes with a gear 67 mounted together with a toothed segment 63 on a layshaft 64. The segment 63 has a radial crank-arm 62 connected by a pin 69 to one end of a rod 61, the other end of the rod being connected to a crankshaft 57 on which is keyed a flanged sleeve 57c mounting a gear 57a. The crankshaft 57 is rotated by the motor 51 through a reduction gear 52 and a chain 55, one of the chain sprockets being integral with a gear meshing with the gear 57a. The angle of oscillation of the sleeve and thereby the tube 11 is predetermined by the adoption of the appropriate distance between the axes of the pin 69 and segment 63 and of the gear ratios in the transmission between the shaft 53 of the reduction gear 52 and the sleeve 35. Translatory movement of the carriage. Mounted on the underside of the lower flange 5 of the beam 1 is a rack 74, Fig. 4, engaged by a gear 70 on a shaft 71 journalled in the carriage housing 38. The gear 70 meshes with and is driven by a clutch pinion 75 splined on and arranged for displacement along a shaft 76 extending transversely of the housing and rotated by bevel gears 78, 79, the gear 79 being keyed to the crankshaft 57. The gears 75, 78 are formed with dog clutch members 80, 81 engageable in one axial position of the gear 75. Motor control. The means provided on the beam 1, Fig. 1, for controlling the operation of the motor comprises a forward limit switch 82 having a pair of depending actuating arms 83 engageable by one of the front rollers 6 of the carriage 8 so that when the carriage reaches the forward terminal position the switch produces a stoppage and reversal of the motor. A similar switch 84 is operated by the rear rollers 7 of the carriage in the fully retracted position of the latter to cut out the motor. Coupled with the switch 82 is a switch 87 having an arm 88 which is engaged by the carriage to cut out the motor should the carriage over-run the forward terminal position. Cleaning fluid control valve. The valve 50, Fig. 15, comprises a casing 108 having horizontally-disposed inlet and outlet ports 109, 110 between which is provided a seating 111 co-operating with a coned piston valve 112 fitted to one end of a stem 113 arranged for axial displacement through a stuffing box 114, the valve 112 being formed with a hollow cylindrical part 120 slidable over a guide projection 121. Steam pressure and a spring 132 urge the valve to the closed position. The casing 108 is secured by studs 116 to a housing 107, Fig. 12, enclosing the valveactuating means. Valve actuating means. An escapement lever 104, Figs 1 and 12, engageable by the rollers 6, 7 of the carriage is mounted on a spindle 105 and secured to a segmental cam 133 the opposite ends of which are formed with depressions 135, 136. Movement of the lever 104 produces displacement of a roller 137 carried on a plunger 130, and as the cam rotates the plunger moves upwardly and through a series of pivoted links 126, 128 pivots a trigger arm 124 which operates a valve-operating plunger 118. The lever and cam assembly 104, 133 is balanced by a weight 134 to assist in the tripping displacement of the roller 137. The lever 104 is provided with spaced-apart prongs 138, 139 and 140, the angle between the prongs 138, 139 being greater than the angle between the prongs 139, 140 so that as the carriage 8 moves forward the leading prong 138 partially operates the cam when the nozzle 14 is about to enter the boiler ; the prong 139 which is engaged by the rear roller 7 of the carriage completes the opening movement of the valve and the roller 137 snaps into the depression 136. The valve 112 is closed on retraction of the carriage and by contact between the roller 7 and the prong 140. Manual operation of the carriage. The drive from the motor 51 may be disengaged to permit traverse of the carriage to be effected by means of removable, cranked handles mounted on squared portions 101, Fig. 6, of the shaft 76. A hand control lever 89 is connected to a shaft mounted in the wall of the carriage housing 38 and having a bifurcated lever 91 engaging the ends of a pin 92 passing through a clutch control shaft 93 slidably supported for axial displacement in the housing 38 and having secured thereto an arm 95 which engages in a peripheral groove in the gear 75. The shaft 93 also carries a pawl arm 96, Fig 10, having a pawl 97 engageable with the teeth of a ratchet wheel 98 mounted on the shaft 76, the free end of the arm being slidable along the inclined surface of a cam 100, Fig. 11. When the dogs 80, 81 of the gears 75, 78 are engaged, as shown in Fig. 6, for traverse of the carriage by the motor 51, the lever 89 is held by a detent 99 in an upper position and the arm 96 is held on a high part of the cam 100 so that the pawl 97 is disengaged from the ratchet wheel 98. The lever is depressed to rock the lever 91 so that the shaft 93 is displaced and the dogs 80, 81 disengaged ; simultaneously, axial movement of the shaft 93 moves the free end of the arm 96 down the cam 100 so that the pawl 97 engages the teeth of the ratchet wheel 98 to prevent oscillating movement being imparted to the tube 11 while the shaft 76 is manually rotated to retract the carriage. Forward movement of the carriage is effected by removing a cover plate 102 to allow lifting of the arm 96 and thus disengaging the pawl 97 from the ratchet wheel 98. Reference has been directed by the Comptroller to Specification 636,052.