Patent GB-1137954-A (GB)
Title: Improvements in or relating to soot blowers
IPC: F28G15/02
Filed: 1966-08-25
Abstract: 1,137,954. Soot-blowers; change-speed gear. DIAMOND POWER SPECIALTY CORP. 25 Aug., 1966 [9 Sept., 1965], No. 38224/66. Headings F2D and F2N. In a soot-blower wherein a lance tube 26 is telescopically interfitted with a feed tube 40 and is slidable thereover from a retracted to a projected position and vice versa, there are means for sliding the lance tube longitudinally of the feed tube between retracted and projected positions, in which positions it overlaps the feed tube by greater or lesser amounts, an auxiliary supporting means positioned adjacent a part of the feed tube which is overlapped by the lance tube when the latter is retracted but which is not overlapped by the lance tube when the latter is projected, and means for moving the auxiliary supporting means laterally towards and from an underlying supporting position with respect to the feed tube. The lance tube is secured to and actuated by a carriage 50 supported in depending position by and moved by a reversible electric motor along tracks supported by a beam 20, the rear sections W of the tracks being straight and horizontal and continuing into downwardly sloping and horizontal intermediate sections X and Y and to final upwardly sloping forward sections Z. The sag-preventing and supporting means comprises rollers 175, 176, Fig. 9, journalled in a cradle 177 and adjustable to the pitch of the helix of lance tube travel, the cradle being carried by a structure 179 the arms of which are secured to hubs 178 fast on a shaft 180 to which is fastened arm 184 connected by a link 185 to an arm 186 secured to a yoke 188 rockable on a shaft 191. As the carriage moves forward an arm 195, Fig. 5, thereon enters the slot 189 in the yoke and rocks the latter to lift the link above the axis of the shaft 191 thereby permitting the rollers and cradle to swing downwardly so that thereafter downward movement of the feed tube is limited only by the offset cradle-supporting portion 177<SP>1</SP>. When the lance tube is fully retracted the supporting device is arranged so as to maintain the rollers, 175, 176 under the tube in an elevated position. The wall box 30, Fig. 12, is provided with means for discharging sealing air into the boiler 25 and around the lance tube 26, and supporting rollers 96, journalled in a cage 98 rockably suspended on a transverse pin 100, have axes adjustably inclined to conform to the pitch of the helix described by the lance tube during the advance and retraction thereof. The lance tube is formed of sections progressively increasing in internal diameter towards the outer end thereof. The carriage driving motor is carried by a transmission assembly 110 constructed to transmit power at different speed ratios when operated in the forward and reverse directions. The assembly 110, Fig. 13, comprises spaced apart input and output shafts 112, 114, the shaft 112 carrying a pinion 118 fast upon or integral therewith and a gear 120 connected thereto by an overunning clutch 124 of the coiled spring type and which provides a one-way driving connection between the hub 121 of the gear 120 and a sleeve 125 the driving key 126 of which projects into a slot 127 in the sleeve and of 60 degrees peripheral extent, to provide lost motion whereby release of the clutch spring is ensured. The shaft 114 is connected to a shaft of the carriage 50 and carries a gear 133,which meshes with the pinion 118 and has a hub 135 concentric with a hub on the gear 128, a sleeve 140 keyed against rotation by a pin 144 surrounding the hubs; the latter are bridged by a one-way clutch spring 146. The lance tube 26, provided with nozzle openings 36, is secured to the carriage 50, Fig. 6, and is in sealed relationship with the feed tube 40 through a packing assembly 52. The lance tube is connected to a hub 58 to which a rotary drive is imparted through a bevel gear 70 the driving key 59 of which is fast on the hub but is fitted in a 90 degree slot in the gear so that independent rotation of the parts are permitted to this angular extent whereby the lost motion establishes different helical blowing paths during projecting and retracting movement of the lance tube. Gear 70 meshes with bevel gear 165 and is rotated through a face gear 162 on shaft 164 and a pinion 160 carried by a shaft 158 which mounts a spur gear 156. The latter meshes with a gear mounted on the shaft (150), Figs. 4 and 6 (not shown), of the carriage which is connected to the shaft 114 of the assembly 110 and carries a helical gear (152) meshing with a face gear (154) fast on a shaft (105), these two gears being self-locking so that a drive cannot be transmitted from gear (154) to gear (152). Shaft (105) carries pinions (106), (107), Fig. 4 (not shown), mounted adjacent rollers (90), (91), and meshing with racks (92), (93) so that rotation of the shaft causes the pinions to drive the carriage along the tracks constituted by pairs of rails (87), (89) and (85), (86) which are secured to the inner faces of the walls (29), (27) of the beam structure 20.