Improvements in or connected with Regulating or Controlling Devices applicable among other purposes for Controlling Dampers for Furnaces.
Реферат: 15,016. Thwaites Bros., and Bullock, H. June 27. [Cognate Application, 20,470/11.] Regulating delivery by varying speed and power of motor.-In a ratchet-gearing mechanism, described in its application to the regulation of furnace dampers and mechanical stokers according to the pressure of steam in the boiler or other condition, and applicable also for the regulation of blowers, fans, compressors, pumps, &c. according to the pressure of the delivered fluid, the operation of a continuously-driven pawl on the ratchet-wheel is controlled by a Bourdon-gauge tube, thermostatic bar, or the like subjected to the controlling condition, through a mask or shield which is oscillated by the pawl arm. In the form shown in Fig. 1, reversed ratchet-wheels 6, 7 connected by suitable gearing to the dampers &c. are driven by pawls 4, 5, either or both of which may be prevented from operating by a shield 17 carried by a shaft 19 concentric with the shafts of the ratchet-wheels and the pawl arm. The shield 17 is oscillated from the pawl arm through pins 16, 35 and spring-connected arms 21 pivoted to the shaft 19 and, in the normal position shown, moves with the pawl arm in both directions, thus holding both pawls out of engagement. Should the pressure rise or fall, the Bourdon gauge tube 1 operates through connexions 27, 29 a pallet 24, one arm or other of which engages the plate 23 and prevents movement of the shield in one direction. The pawl on that side is consequently allowed to engage with its ratchet-wheel, and the damper is opened or closed according to the change of pressure &c. The pressure at which the apparatus is brought into operation can be varied by an eccentric 39 acting on the spring support 28 of the rod 27. The pallet 24 is pressed against the end of the rod 29 by a spring 30. Additional adjustable shields fixed to and moving with the ratchetwheels may be provided to prevent the entire closing of the damper, and the shield 17 may be made longer on one side than the other, so that the dampers open quickly and close slowly, or vice versa. In a modified form, Fig. 3, with a single pawl and ratchet-wheel, the shield 17 regulates the effective stroke of the pawl. The stop for the tooth 44 fixed to the shaft 19 may either be a stepped arm, as shown, or a singlearmed stepped pallet. One of the arms 21 may be fixed to the shaft. In another arrangement, with reversed ratchet - wheels and a stepped double pallet, two fixed shields on each ratchetwheel may be provided, one shorter and the other longer than the maximum stroke of the pawl. The shorter shield throws the pawl out of gear when the damper is nearly closed; but if the controlling pressure still continues to rise, the pawl acts on the teeth behind the shorter shield and closes the damper completely. In this position, further rotation of the ratchetwheel is prevented by the long shield.
Improvements in and relating to control means for furnaces and the like having fuel burners
Номер патента: GB476439A. Автор: . Владелец: Baker Perkins Ltd. Дата публикации: 1937-12-08.