Patent GB-743712-A (GB)
Title: Fluid operated control unit for a plurality of power operators
Inventor: MASHEDER HENRY
IPC: F15B11/20
Filed: 1952-12-15
Abstract: 743,712. Controlling operation of sootblowers. GORDON & CO., Ltd., J. Jan. 26, 1954 [Dec. 15, 1952], No. 31783/52. Class 99(2). [Also in Group XXIX] A fluid-operated control unit having a single controlling position is provided with separate manually-operable means, e.g. valves 23 ... 26, for controlling each of a number of power operators e.g. soot-blowers A, B, C and D, further manually-operable means, e.g. a valve 20, to cause an operation of all the power operators in a predetermined sequence, and means incorporated in each of the valves 23 ... 26 to exclude the operator controlled thereby from a sequential operation. The sootblowers may be of the kind that perform a number of rotational movements after having been advanced to an operative position. As shown in Fig. 2, push-buttons 7, 8 respectively control, by an air motor E, the opening and closing of a master valve 9 which admits steam, i.e. the cleaning medium, through a line 19 to individual valves 10 ... 13 forming part of each soot-blower A ... D, and there are indicator lamps which show when the steam system is drained and the valve 9 is open. The unit is operated by a constant pressure air supply connected at X which supply also operates motors actuating the nozzles and steam valves of the soot-blowers. The air supply is led to the unit through a valve 16 controlled by a thermo-sensitive device 17 exposed to the conditions in the drain 18 from the line 19 and arranged to admit air to the unit and up to the inlet valves of the motors actuating the blowers only when the line 19 is properly drained. The air is led from the valve 16 to the inlet of the valve 20 which is controlled by a push-button 5, and to a central port of a valve 21 controlled by a push-button 6 and for immediately halting a sequential operation of the soot-blowers. The outlet ports of the valve 21 communicate respectively with the valve 22 controlled by the push-button 8, and the first of the valves 23 ... 26 each controlled by push buttons 1 ... 4. The arrangement of the valve 21 is such that when shifted by the button 6 air is admitted to shift the valve 22 to close the valve 9 through the agency of the motor E and air is simultaneously cut off from the valve 23. The ends of the valve 21 are connected to the outlet of the valve 20 and the outlet of the valve 26 so that the valve 21 is shifted to the open position when the valve 20 is opened and is closed when the sootblower D controlled by the valve 26 has completed its operation. The outlet of the valve 20 is also connected to all the valves 23 ...26. Soot-blower control valves. As shown in Figs. 3 and 4, a shuttle valve provided with four lands is shifted manually by a push-button 1, or by pressure fluid admitted through ports 47a to a chamber 47, and there is an inlet port 27, a port 28 leading to the inlet port of the next of the series of valves, and a port 29 communicating with the inlet valve of the motor of the sootblower controlled thereby. Ports 30, 31 are exhaust ports to atmosphere. The valve is rigidly connected by a spindle 32 to the button 1 which is provided with a pin 33 slidable in an axial slot in a housing 34 when the button is in the position for sequential operation of the sootblower, but which enters a circumferential slot 35 to lock the button and valve against axial movement when the button is appropriately rotated. Mounted in the valve housing is a pressure operated step-by-step mechanism by which the valve is returned to its initial position after being shifted manually or by a pressure impulse derived by pushing the button 5, and this mechanism comprises a hollow piston 36 urged by a spring 37 away from the valve and having on its outer surface a number of ratchetlike projections 40 and a tongue 41 slidable in a groove 42 to prevent rotation of the piston. When air pressure is transmitted to the air valve of the soot-blower motor via the port 29-air also passes through the passage 39 to overcome the pressure of the spring 37. Pressure impulses signalled from means provided on the sootblower on completion of each of a series of operations of the soot-blower, are transmitted to a spring-loaded piston 43, Fig. 5, carrying lugs 44, 45. As shown the first of the projections 40 has engaged the lug 45 and a pressure impulse from the soot-blower moves the piston 43 to disengage the lug 45 from the projection 40 and engage the lug 44 with that projection so that the piston 36 advances a distance equal to that between the faces of the lugs. On completion of a 'rotational movement by the sootblower the pressure applied to the piston 43 is dissipated and the piston releases the projection 40 engaged by the lug 44 so that a further step is taken by the piston 36 and the next projection 40 is engaged by the lug 45. The piston 36 continues to advance in this manner until a projection 46 contacts the valve to shift the valve and button 1 to their initial position, the port 29 being put into communication with the exhaust port 30 to release pressure from within the piston 36 which is pushed back to its initial position by the spring 37, the lugs 44, 45 being free to rotate. A pin 48 adapted to be inserted in one of a number of holes 49 limits the backward movement of the piston 36 so that the number of rotations performed by the sootblower controlled by the valve can be preset. The operating button of a micro-switch is located in the path of the piston 43 and with every advance of the piston a circuit illuminating an indicator lamp is closed. In operation, the button 7 is pushed to admit compressed air to the motor E which opens the valve 9, steam being admitted to the valves 10 ... 13 and con - densate being discharged through the drain 18. The device 17 allows air to be supplied through the valve 16 to the unit and to the inlet valves of the soot-blower motors. If a sequential operation of the soot-blowers, for example, except C is required the button 3 of the valve 25 is rotated to engage the pin 33, Fig. 4, in the groove 35 and operation of the button 5 indexes the valve 21 to a position whereby air is transmitted to the inlet port 27 of the valve 23, and simultaneously the valves 24, 26 are indexed to their operative positions by air admitted to the chambers 47, Fig. 4, of those valves. The air admitted to the valve 23 passes through the port 29 of that valve to the inlet valve of the motor actuating the soot-blower A the latter commencing its cycle of operations and at the termination of each rotation in one direction transmitting a pressure signal to the piston 43. On completion of the pre-set number of phases of operation the piston 36 of the step-by-step mechanism indexes the valve 23 back to its initial position and is returned by the spring 37 to its starting position, air pressure being cut off from the inlet valve of the motor of the sootblower A and admitted to the inlet port of the valve 24. A similar cycle of operations takes place as regards the valves 24 and 26, the air pressure passing directly from the inlet port 27 of the valve 25 to the inlet port of the valve 26 since the valve 25 has been locked in the inoperative position. After the soot-blower D has concluded its cycle of operations, air pressure from the port 28 of the valve 26 passes to the valve 21 thus admitting pressure to the valve 20 and shutting off pressure to the valve 23.