US2200663A - Soot blower - Google Patents

Description

A. M. WILSON SOOT BLOWER May 14 1940.,

s L AN A y 14, 1940- A. M. WILSON 2,200,663

SCOT BLOWER Filed Dec. 1, 1937 5 Sheets-Sheet s Patented May 14, 1940 UNETED TATES greases PATENT oFricE SOOT BLOWER Allan Murray Wilson, Clydebank, Scotland Application December 1, 1937, Serial No. 177,415 In Great Britain June 6, 1936 8 Claims. (01. 122-392 An object of the invention is to provide a soot blower of the character stated which will be operable in an improved manner to direct the cleaning fluid upon an area to be cleaned.

Another object is to make use of a powerimparting assembly including a power unit to operate the soot blower, which unit will be driven to-and-fro under the control of a controller actuated to move relatively to the power unit towards the end of each motion of the power unit in order to reverse such motion.

Another object is to make use of pressure fluid as the medium which operates the soot blower, such pressure fluid being preferably drawn from the same source as the cleaning fluid, although 'a hydraulic or pneumatic fluid could be used instead.

"Another object is to provide means whereb operation of the soot blower is automatically stopped on completion of a predetermined plurality of vto-and-fro movements of the power unit operating it.

Another object is to provide automatic cut-off means applicable to a plurality of soot blowers and adapted to stop each successive soot blower on completion of a predetermined plurality of to-and-fro movements of the power-unit operating the respective blower.

' Other objects of the invention will be apparent from the following specification and claims.

A soot blower having a steam power unit and associated electrical starting and cut-ofi apparatus will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

Figs. 1A and 13 together constitute a sectional view oi the soot blower, power unit and associated apparatus.

' Fig. 2 is a sectional view, drawn to a larger scale, of a device incorporated in said apparatus, the section being on the line 22 of Fig. 6.

Fig. 3 is an electric wiring diagram including parts of the apparatus already shown, but to a smaller scale, in Fig. 1.

Figs. 4 and 5 are views of the aforesaid parts of the apparatus but showing these parts in diiierent positions.

Fig. 6 is a section on the line 66 of Fig. 1B, with parts omitted for clearness.

. The soot blower includes a fluid-ejector constituted by a nozzle ll! secured to a tube 1 l which is provided with valve means for admitting steam.

to pass through it to the nozzle, and in the construction shown the valve means includes ports l2 formed in the tube H. The tube H is slidable and turnabie in a stationary casing including a chest I 3 through which steam passes to the ports l2 from. an inlet branch l4 whenever the tube is advanced to displace the nozzle into an operative zone beyond a boiler-wall box IE to which the chest i3 is attached. The boiler wall is denoted by C. The box l5 and wall 0 afiord a shelter for the nozzle when the latter is withdrawn to its inoperative position (see Fig. 1) in which the ports H are masked by the chest 53, and so steam is shut-off from the nozzle.

The nozzle Ill has been conventionally represented but it may be a single, double or other nozzle adapted to eject steam at an inclination or inclinations to the axis of the tube H.

The steam power unit comprises a piston 20 reciprocab le in a cylinder 2| rigidly secured to the casing which includes the chest it. The piston rod 22 is secured to an extension. 23 of the ported tube H, the extension 23 being provided with a cam pin 24 engaging in a helical cam track 25 which may be of helical form formed in a casing structure 26 between the chest l3 and cylinder 2|. An extension 21 of the piston rod is fitted with a hand wheel 28 for manual operation of the blower; for example, for testing purposes. Steam is supplied to the cylinder by way of a pipe 29 which ordinarily would be led from the source which supplies steam to the blower itself; The supply of steam to the cylinder is controlled by a spring-closed stop valve 30 and a slide valve 3| which in the construction shown is of the piston type. The exhaust steam can be led by a pipe 32 to the wall box IE for cooling thereof. The stop valve is operated by an electro-magnetic device, conventionally represented as a solenoid 33, and an electric main switch 34. The piston valve is operated by stops 35' and 35 which are secured to a valve rod 36 and which are located towards opposite ends of the path of movement of the pin 24, so that these stops will be alternately struck by the pin and displaced to move the piston valve. The valve rod is held against rotational movement by a feather-and-groove connection 31a with a supporting bracket 31 on the structure 26.

When the soot blower is to be started, the stop valve 30 is opened, as hereinafter described, and so steam is admitted to the piston valve 3| of the piston-and-cylinder assembly 20, 2| and directed by said valve to one end of the steam cylinder. The piston 20 is forced towards the other end and as it moves the rigid nozzle assembly which includes the extension 23 rocks toand-fro under the control of the cam track 25 acting on the pin 24. As the piston approaches the opposite end of the cylinder, the pin strikes one of the stops 35', 35 and accordingly displaces the piston valve. Thus, the direction of steam to the cylinder is reversed and the piston is forced to return. That is to say, the piston reciprocates and forces the blower nozzle to reciprocate, and at the same time the rocking action due to the cam is imparted to the nozzle.

The main switch 34 has a no-volt release, i. e., if the electric circuit 38 controlled by the switch ceases to be closed then the switch instantaneously opens.

Means are shown whereby the soot blower will be automatically cut-off as soon as it has performed some predetermined number of reciprocations; for example, six reciprocations. The means shown include a ratchet-wheel 39 whose pawl 40 is actuated by a striker 4| secured to the piston-valve rod 36. The ratchet device is such that a shaft 42, which is journalled in the bracket 3! and bears the ratchet Wheel 39, is turned step-by-step as the blower continues to operate, the shaft 42 receiving one step per complete reciprocation of the blower. The shaft 42 is fitted also with a cam 43 and this cam acts upon a lever 44 having a stationary fulcrum 45, the lever being continuously pulled against the cam by a spring 46. The lever has an electric contact 41 which co-operates with a second contact 48 on a second lever 49 having the same fulcrum. The second lever 49 is continuously pulled towards the first lever 44 by a second spring 50, i. e., the second spring continuously strives to hold the second contact hard against the first contact. The second lever is connected to a slow-acting dashpot 5|. I

The contacts 47, 48 are connected in the electric circuit 38, and they are normally closed.

When the prescribed number of reciprocations of the blower nozzle have been completed, the cam 43 has by that time turned from a position (see Fig. 4) in which it has fully lifted the levers 44, 49, into the position in which the drop of the cam has just passed beyond the first lever 44. In view of the drop, the first lever 44 (see Fig. 5) snaps under the pull of the first spring 46 away from the second lever 49 which is prevented from moving in unison by the slow-acting dashpot 5!; the first contact 41 moves away from the second contact 48 and opens the electric circuit 38; and so the main switch 34 opens, the

solenoid 33 is tie-energized, and the stop valve 30 closes. That is, steam to the cylinder 2| is shut off.

Under the pull of spring 5|], the second lever 49 slowly follows the first lever 44 until the contact 48 engages contact 41 (see Fig. 3).

Means may be provided for regulating the extent of operation of the soot blower. For example, by providing on the bracket 31 a ratchetshroud or cam 40a to guide the pawl 40 into and out of engagement with the teeth of the ratchetwheel 39 and by making provision for adjusting the setting of the ratchet striker 4| on the rod 36, the angular displacement of the ratchet-wheel and the cam 43 at each stroke of the pawl can be varied in size, and accordingly the number of reciprocations of the blower per period of operation can be varied.

The main switch 34 can have control of as many soot blowers as desired; for example, all the blowers of one boiler (or other heat exchanger) or even all the blowers of a plant. The respective blowers would have their own switches El, E2, and so on, so that the operator would close the individual switch of any selected blower (or blowers) and then close the main switch 34, which would automatically open as soon as the blower (or blowers) had completed the extent of work predetermined.

Ordinarily, the soot blowers would be operated in succession. That is to say, the operator would commence blowing operations by closing the first blower switch El and the main switch 34, and the first blower would thus be set in operation and would remain in operation until its ejector l0 had performed the number of movements prescribed, whereupon the main switch would open. The operator would then open the first blower switch El, close the second blower switch E2 and close the main switch. This procedure would be continued until all the blowers had been operated.

I claim:

1. A soot blower comprising a casing, a cleaning-fluid ejector movable in said casing, a powerimparting assembly including a power unit operatively connected to the ejector and operable by a driving medium supplied to said assembly, said unit being axially movable under the action of said medium with to-and-fro strokes to impart axial to-and-fro movement to the ejector, means for superimposing on the ejectors axial movement a turning movement, means controlling the supply of driving medium to said assembly, directioncontrolling means for reversing the direction in which the driving medium is applied in said assembly to said power unit so as to cause reversal of the movement thereof, means actuating said direction-controlling means about the end of each stroke of the power unit in order to reverse the movement of the power unit, and means actuated by repeated movements of the power unit and adapted to cause said supply-controlling means to cut-off the supply of driving medium following performance of a predetermined pluand-pawl mechanism operated under the action of said unit, cam mechanism operated by said ratchet-and-pawl mechanism and valve-closing means actuated by said cam mechanism.

3. A soot blower comprising a casing, a cleaning-fluid ejector movable in said casing, a pressure-fiuid-operated power-imparting assembly including a power unit operatively connected to the ejector, said unit being axially movable under the action of the pressure fluid with to-and-fro strokes to impart axial to-and-fro movement to the ejector, means for superimposing on the ejectors axial movement a turning movement, means controlling the supply of pressure fluid to said assembly to operate said power unit, directioncontrolling means for reversing the direction in which said pressure fluid is applied in said assembly to said power unit so as to cause reversal of the movement thereof, means actuating said direction-controlling means at the end of each stroke of the power unit in order to reverse the Ill) movement thereof, electro-magneticmeans arranged in an electric circuit and adapted to actuate said supply-controlling means to open the supply of pressure fluid to said assembly, and devices adapted to open said electric circuit on completion of a predetermined plurality of toand-fro movements of the ejector and thus cause the supply-controlling means to shut-off the supply of pressure fluid to the power unit.

4. A soot blower comprising a casing, a cleaning-fluid ejector movable in said casing, a powerimparting assembly including a power unit operatively connected to the ejector and operable by a driving medium supplied to said assembly,

1 said unit being axially movable under the action of said medium with to-and-fro strokes to impart axial to-and-fro movement to the ejector, means for superimposing on the ejectors axial movement a turning movement, a controller associated with said assembly, means actuating said controller to reverse the movements of the power unit, electro-magnetic means controlling the supply of driving medium applied to said unit in said assembly, said electro-magnetic means being and arranged in an electric circuit, relatively movable but normally closed contacts in said circuit, mechanism for opening said contacts to bring about stoppage of the supply of driving medium under the action of the electromagnetic controlling means and a device for delaying re-closure of said contacts.

5. A soot blower comprising a movable cleaning-fluid ejector, a power-imparting assembly including a power unit for operating said ejector and admission means for admitting driving medium to said assembly, in combination with electric starting and stopping apparatus comprising an electric control circuit, means connected in said circuit for controlling the opening and clos-v ing of said admission means, a starting switch connected in said circuit and adapted to close said circuit and thus actuate said opening-andclosing control means to open said admission means, a self-acting switch connected in said circuit and adapted to open said circuit and thus actuate said opening-and-closing control means to close said admission means, and means actuated by the power unit to bring about automatic opening of said self-acting switch on completion of a predetermined plurality of movements of the power unit.

6. A soot blower comprising a movable cleaning-fluid ejector, a pressure-fluid-operated powerimparting assembly including a power unit peratively connected to the ejector, said unit being adapted to move the ejector in two opposite directions, means controlling the supply of pressure fluid to said assembly to operate said power unit, direction-controlling means for reversing the direction in which said pressure fluid is applied in said assembly to the power unit so as to cause reversal of the movement thereof, means actuating said direction-controlling means at the ends of the movements of the ejector in both directions in order to repeatedly reverse the successive movements of the ejector, electro-magnetic means arranged in an electric circuit and adapted to actuate said supply-controlling means to open the supply of pressure fluid to said assembly, and devices adapted to open said electric circuit on completion of a predetermined plurality of to-and-fro movements of the ejector and thus cause the supply-controlling means to shut-off the supply of pressure fluid to said assembly.

'7. A soot blower comprising a turnable cleaning-fluid ejector, a pressure-fluid power assembly consisting of a piston element and a cylinder element, one of which elements is axially reciprocable and is operatively connected to the ejector, means for transposing the reciprocatory movements of the reciprocable element into turning movements of the ejector, a slide valve actuated by the reciprocable element to direct pressure-fluid to-and-from opposite ends of the cylinder element, a stop valve controlling the supply of pressure-fluid to the slide valve, an electi e-magnetic device to control the opening and closing of said stop valve, said device being connected in an electric circuit, a starting switch connected in said circuit and adapted to close said circuit and thus actuate said electromagnetic device to open the stop valve, a self-acting stopping switch also connected in said circuit and adapted to open said circuit and thus de-energise said electro-magnetic device and cause the stop valve to close, and means actuated by the reciprocable element on completion of a predetermined plurality of reciprocations to cause opening of the stopping switch.

8. A soot blower comprising a casing, a cleaning-fluid ejector movable in said casing, a powerimparting assembly including a power unit operatively connected to the ejector and operable by a driving medium, said unit being axially movable in both of two directions under the action of said medium so that said unit imparts toand-fro rotational movement to the ejector, a controller associated with said assembly, means actuating said controller to reverse the movements of the power unit, electro-magnetic means controlling the supply of driving medium to said assembly and arranged in an electric circuit, relatively movable but normally closed contacts in said circuit, and mechanism actuated by said unit to open said contacts and bring about stoppage of the supply of driving medium under the action of the electro-inagnetic controlling means after a predetermined number of two-directional movements of said unit.

' ALLAN MURRAY WILSON.

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