GB491915A - Improvements in and relating to systems controlling the sequential actuation of electrically operated soot blowers - Google Patents

Abstract

491,915. Control of several motors. BRITISH THOMSON-HOUSTON CO., Ltd., BOURNE, S. N., and JEFFERSON, H. F. March 8, 1937, No. 6825. [Class 38 (iii)] Travelling to predetermined limits.-In an electrically operated soot blower the sequential actuation of the several blower heads is controlled by a sequence switch including a movable contact operated by a relay, the control circuits including switches controlled by the respective blower heads and effective to maintain the energizing connections at the commencement of the operation of a blower head, and for disconnecting the energized circuit and establishing energizing connections for the next blower head at the completion of the operation. With hand switches 30, 31, in the position shown operation of a starter button 34 energizes a self-maintaining relay 35 to energize a contactor 37 and start a motor operating the first head 24. The initial movement of the head closes a switch 38. A relay 39 closes and a coil 40 is energized to operate a pawl reciprocated by a motor 41 into engagement with a ratchet wheel on a spindle of a sequence switch whereby this switch moves from contacts 24a associated with the first head to contacts 25a associated with the next head 25. As the contacts 24a are left, the relay 39 is de-energized and the motion of the sequence switch is stopped. Additional manually-operated switches 72 may be provided in case of the relays 39 sticking. A centrifugal switch 42 controls a lamp 43 and an audible alarm 46, to give indications if the operation of the motor stops. A switch 47 is operated to reverse the motor between limits of travel and at each reciprocation a ratchet 50 is operated, and after a predetermined number of reciprocations, a switch 49 is opened to stop the operation of the first head. The relay 35 is de-energized to open the contactor 37, and contacts on the relay 35 effect closure of a relay 56 to initiate a similar operation of the next head. Similar control is then effected for each of the remaining heads. In the case of heads 27, 28 and 29, which are of the type not inserted and retracted for operation, the control is effected by a contactor 59, and a switch 61 closed when the head commences to operate, and opened after a predetermined number of revolutions. The switch 61 is opened by means of a star-wheel 65, stepped by rotation of the motor. Further contacts 67, 68, 69 are provided on the sequence switch connected together and acting as blank contacts for use when additional heads are to be controlled. The operation of any particular head may be omitted by moving a corresponding switch 31 to its closed position, and to operate any individual head, a switch 71 is operated after movement of the switch 30 to its hand position. Further description is given with reference to simplified diagrams, Figs. 1 and 2 (not shown). Specification 491,916, [Group XXVIII], is referred to.