US3089468A - Sootblower - Google Patents

Description

y 4, 1963 E. w. CLARK 3,089,468

SOOTBLOWER Filed Aug. 29, 1960 2 Sheets-Sheet 1 I Q l In, I E

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EDWIN WILLIAM CLARK INVENTOR A-TTORN Y3 A Q Weed, (540L012, fiiw w E. W. CLARK May 14, 1963 SOOTBLOWER W m 2 m M w w M h T A Y ,r M m w y w w w m m W L z W s E m A w W hm p a 3 3 8. A 7 k wm ll IIIIIII wm 3 \w w s Mm x m \m 3 {w R nU fl Q! 7 I l I l IIHII o wm Q z/ mm W\/ N 0% Mb M 9, x I I I I I Ll... 1| 7 Om 2 H k K. 3 A Q \h w mm \m w MN m United States Patent 3,089,468 SOOTBLOWER Edwin William Clark, Crows Nest, near Sydney, New South Wales, Australia, assignor to John Thompson (Australia) Pty. Limited, Crows Nest, near Sydney, New South Wales, Australia Filed Aug. 29, 1960, Ser. No. 52,701 Claims priority, application Australia Sept. 8, 1959 4 Qiairns. (Cl. 122-392) This invention relates to sootblowers; that is, those devices by which jets or blasts of steam, air or other cleaning fluid are directed on to the fire-exposed surfaces of the tubes or other parts of a boiler in order to clear accumulations of soot, ash and the like from those surfaces.

The invention is applicable generally for sootblowing purposes in boiler or other fire-boxes of any kind, but the invention is primarily intended for use with water-tube boilers of the large scale type used in power stations and the like and particularly those which are in constant service to the extent, for example, of running continuously for as much as more than twelve months at a time, and the invention is described herein mainly in terms of sootblowers intended for that particular purpose.

Existing sootblowers of the kind indicated are largely satisfactory in operation; but nevertheless, they are open to objection in several respects, for example, they are relatively expensive and mechanically complex, and the cleaning fluid delivery nozzles which project into the firespace of the boiler, require frequent renewal due to burnvent leakage therebetween is eliminated, and in which most a of the blower tube is completely shielded from fire damage except for an inexpensively renewable tip portion thereof; and, if desired, not merely shielded as just indi cated but also water-cooled by use of the water in the boiler and thus without necessity or even desirability for provision of expensive and complex air or water cooling arrangements as have in some cases been proposed heretofore.

A sootblower according to this invention, comprises, a stator assembly adapted for mounting on a boiler or like fire-box, a bearing tube which forms part of the stator assembly and extends through the fire-box wall to the inside of the fire-box, a movable assembly which is end- Wisely movable inside the stator assembly, a blower tube which is housed inside the bearing tube and forms part of the movable assembly and which has a cleaning fluid outlet at its end nearer to the inside of the fire-box, means for feeding cleaning fluid under pressure to the outlet, actuating, devices incorporated in said assemblies which in response to application of fluid pressure thereto axially advance the blower tube so that its outlet end projects into the fire-box beyond the adjacent end of the bearing tube, and means for retracting said blower tube from its axially advanced position.

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Examples of the invention are illustrated in the drawings herewith.

FIG. 1 is a sectional side elevation showing part of the ,fire-box wall of a water-tube boiler with a simple embodiment of a sootblower applied thereto.

FIG. 2 is a view similar to FIG. 1 showing a sootblower substantially the same as that of FIG. 1 except for its incorporation of a number of features of mechanical dein the wall or shell 7 thereof and through any refractory material 8 which lines that wall. :fixed in position by a mounting flange 9 or the like secured by studs or otherwise on the outside of the boiler This bearing tube is shell. The mounted bearing tube may project between adjacent water tubes and may itself, to protect it from the fire, be coated with refractory material. For preference, however, the bearing tube passes diametrically through one or more of the water tubes 10 of the boiler so that it will be kept relatively cool by the water therein. The bearing tube may extend through holes formed in the water tube or tubes and is welded 11 or otherwise fixed in position for leak-proofing purposes.

The bearing tube forms part of a stator assembly which includes a cylindrical chamber 12 having an opening at each end. At the outer end the chamber opening 13 is adapted to receive a pipe or other connection to a source of steam, compressed air or other cleaning fluid. The

opening at the inner end of the cylindrical chamber leads to the entrance end portion of the bearing tube.

A nozzle or blower 14 forms part of a movable assemvbly which is endwisely and rotationally movable relative to the stator assembly. The inner or fire-space end of the or other removable closure, in which case one or more tube adjacent the fire-space end thereof. Where a plug such as 15 is used, its end 17, within the blower tube may be coned or obliquely shaped as shown in order to avoid, as much as, possible, the presence of surfaces which might be obstructive to the steam of cleaning fluid or cause unnecessary turbulence therein. As an alternative, a plug may be omitted and the outlet end of the blower tube fashioned to constitute a restricted nozzle outlet by which the working fluid may be directed towards the surfaces to be cleaned as may be required. The outer end of the blower tube has what may be called an impeller piston 18 fixed thereon. This piston has oblique or helical holes therein, or is helically grooved about its periphery, or is otherwise furnished with impeller vane elements such as 19 so that the piston, when exposed to a stream of cleaning fluid led into the cylindrical chamber, through opening 13, and also the blower tube fixed to it,

will slowly rotate. Slowly, that is, by comparison with a conventional turbo-type rotor. For example, it is expected that the piston and its blower tube will be required to rotate at the rate, for example, of about two or three revolutions for operative bursts each of from one half to one minutes duration. The operative bursts being separated by periods measured in hours rather than minutcs.

Although the piston 18 is operative as a turbo rotor, as indicated above, and the passages either as holes, peripheral grooves or the spaces between helical vanes, suffice to give the required rotation; the passage space through the piston is sufficiently restricted to enable the piston to move axially, as a true piston, when it is not restrained against such movement, and means such as compression spring 20, are provided to emplace or hold the piston at the outer end of the cylindrical chamber in the periods between operative bursts thus to keep the inner end of the blower tube retracted and thus normally housed within the bearing tube irrespective of whether that tube is or is not water cooled by penetration through one or more of the boiler water tubes as discussed earlier herein.

It follows that for most of the time the blower tube is retracted and the impeller piston is disposed at the outer end of the cylindrical chamber 18. It follows too, that when the supply of cleaning fluid is first entered into the cylindrical chamber, to commence an operative burst, rotation of the piston and its blower tube will commence immediately; and, at the same time, the piston will be driven to the inner end of the chamber (as shown in FIG. 1) thus to project the blower tube into its working position. If desired, a frictional pad in the form of a washer 21 may be sleeved on the blower tube between the inner face of the piston and the inner end of the chamber so to apply some restaint or braking effect against overfree rotation of the piston and the blower tube when the latter is fully projected into working position.

The blower tube necessarily has mechanical clearance relative to the bearing tube within which it is required to be endwisely and rotationally movable. This clearance is preferably made somewhat generous so that the clearance space 22 will act as an exhaust port by which cleaning fluid which has passed through the turbo passages in the piston may flow into the fire box thus helping to keep both the bearing tube and the blower tube cool, and also to keep the bearing surfaces clean by preventing entry of ash or soot particles between the bearing surfaces; or, if any such particles may have entered that space, by blowing them therefrom. If desired, flow of the turbo exhaust into the clearance space 22 may be facilitated by providing a number of exhaust ducts in the form of oblique drillings 23 which extend from the inner end of the cylindrical chamber to the bore of the bearing tube.

Retraction of the piston and its nozzle tube may be elfected by furnishing the outer end portion of the hearing tube bore with a counterbore recess 24 which houses the compression spring 20. This spring at one end bears against the floor of the counterbore and at its other end bears against the inner face of the piston or (if present) the friction washer 21 mounted thereon. If such a re tracting spring is employed clearly it will be compressed when the piston is moved towards its operative position; and, upon relaxation of the cleaning fluid supply, the spring is then able to exert itself to restore the piston to its inoperative position at the outer end of the cylindrical chamber.

As an alternative to spring retraction, means may be provided for feeding cleaning fluid to the inner or back face of the piston. Admission of fluid to the rear of the piston for retraction purposes may be manually effected by means of a suitable valve, or alternatively an admission valve may be operated automatically and contingently upon closure of the main valve by which cleaning fluid is admitted to the outer end of the cylindrical chamber. Said main valve may also be manually operable, especially where the working bursts are required to be relatively infrequent, or it may be automatically operated and otherwise controlled as to its operation periods and frequency thereof by control devices of more or less conventional kind.

It will be appreciated that in many cases total revolution of the blower tube will not be required, and in such case means may be provided to ensure that the blower tube is only part rotated through any selected angle. If desired, such part rotation may be effected entirely during either retraction or projection of the nozzle tube. In such case the piston need not be provided with turbo passages, simply having one or more radial pegs thereon which engage within corresponding helical grooves or the like formed in the wall of the cylindrical chamber.

It will also be appreciated that where, as is preferably the case, the bearing tube passes through a boiler water tube, the cross-sectional area of the water tube will be diminished by the presence of the bearing tube passing through it. It follows therefore, that if any such reduction of cross-sectional area is to be avoided the boiler water tube in that vicinity may be of somewhat swollen diameter, as indicated at 25, so that there is no loss of water stream space.

Referring to FIGS. 2 to 4, the bearing tube 26 forms part of a stator assembly which includes a casing 27 having a cylindrical chamber 28 formed in it. This stator assembly is mounted in relation to a fire-box shell 29 and preferably also in relation to a water-tube 30, in the same manner as previously described herein with reference to FIG. 1. The blower tube 31 is also substantially the same as that numbered 14 in FIG. 1 except that it is made in two parts separably connected together, as indicated at 32, thus to enable the fire-space end of the blower tube to be easily replaced when necessary without having to replace the whole rotor assembly or even a major part of that assembly.

The main differences between the arrangement shown in FIGS. 2 to 4 and that shown in FIG. 1 are that the FIG. 2 construction includes fluid pressure operated means to retract the rotor assembly instead of a spring, and its impeller piston is made in two parts one of which acts purely as a rotary impeller while the other acts purely as a non-rotating piston.

Still referring to FIGS. 2 to 4, the blower tube 31 has a keyway 33 which is slidable longitudinally of a key 34 fixed in a bearing sleeve 35 mounted in anti-friction bearings 36 in the stator casing 27. Thus the blower tube is freely movable, axially and rotationally, within the bearing tube. The blower tube 31 has an end impeller head 37 having helical impeller vanes 38 on it. These vanes are able to turn freely but with bare mechanical clearance, within the skirt 39 of a piston 40. The open end of the piston skirt carries a mounting disc 41 which provides the necessary support and backing for an ordinary bearing 42 and a thrust bearing 43 by which the blower tube is borne within the piston. The piston is non-rotatable by reason of it having longitudinal keyways which engage keys 44. Buffer springs 45 and 46 are preferably provided at the ends of the cylinder 28 to cushion the piston at the ends of its stroke. The piston has a centre hole 47 which provides opening to the interior of the blower tube, and the cylinder has end hole 48 for admission of pressure working fluid.

The mounting disc 41 has holes 49 in it which align with elbow holes 50 in the piston 40 so that pressure fluid in a duct S l formed in the casing 27 may flow, when the piston 40 is positioned as shown in FIG. 2, through the elbow holes 50, past the vanes 38, through holes 49 and thence to exhaust ducts 52 and 53; the latter opening to the clearance space 54 between the bearing tube and the blower tube as and for the purpose explained with reference to space 22 in FIG. 1.

The supply of pressure fluid to operate the apparatus is by way of pipe and valve arrangements as illustrated schematically in FIG. 2. In the initial position the piston 40 and the parts joined to it would be in their rightmost positions in FIG. 2 and, assuming main valve 55 is open to supply of operating pressure fluid, opening of valve 56 will cause the piston 40 to move to the position shown in FIG. 2, thus projecting the blower tube into the firespace. A three-way valve is provided at 57. This valve is of known kind, in that it has two positions such that fluid may proceed from pipe 58 to pipe 59 or to pipe 60 but not to both of pipes 59 and 60 at one and the same time. When the valve 56 is open the position of valve 57 is such as will send pressure fluid into pipe 59, and under those circumstances, opening of valve 61 will cause working fluid to proceed along duct 51 thus to rotate the head 37. On completion of the sootblowing operation valve 56 is turned off and valve 57 operated so that pipe 59 is closed off and pipe 60 placed under pressure so that working fluid is fed into the ducts 5'2. Some of this infeed will be lost by way of space 54 but its main effect, aided by the cushioning spring 45, will be to move the piston 40 rightwardly (as viewed in FIG. 2 first until its elbow holes lose direct communication with the duct 51, and then for its full travel until halted by the cushioning spring 46. The operation of valves 56 and 57 is preferably mechanically or otherwise interlocked so that pipe 59 is under pressure only when valve 56 is open, and pipe 60 is under pressure only when valve 56 is closed.

Although both of the illustrated forms of the invention show the bearing tube as extending through a water-tube, such as or 30, it will be understood that the bearing tube may extend between a pair of such tubes and in such case the portion of the bearing tube exposed to fire would be suitably designed as to dimensions, and the heat resisting nature of its material, so as to withstand what its conditions of operation would then be.

It will be understood that although it is preferable for the blower tube to be rotatable as herein described with reference to the illustrated examples of the invention, such rotatability may be dispensed with and in such case the blower .tube will preferably be furnished with a plurality of variously directed outlets (such as 16). If desired these outlets may be formed tangentially of the blower tube so that the issuing cleaning fluid jet will turn the blower tube reactively. If the blower tube is not required to rotate, the sootblower arrangement may be substantially the same as those illustrated; except, of course, that the fluid spaces defined by the impeller elements, such as 19 or 38, would then be straight instead of helical.

I claim:

'1. In combination with a boiler having a firebox, a fire-wall surrounding said fire-box, and water tubes within said fire-box; a sootblower comprising a stator assembly mounted on said flre-wall, a bearing tube forming a part of said stator assembly and extending into said firebox and through one of said water tubes, a movable assembly mounted for axial and rotary movement within said stator assembly, a blower tube housed within said bearing tube and forming a part of said movable assembly, a fluid outlet in said blower tube adjacent one end thereof, means for feeding fluid under pressure to said outlet, means responsive to said fluid under pressure to impart axial movement to said movable assembly to project said blower tube outwardly from said bearing tube during the sootblowing operation, turbo-drive means responsive to said fluid under pressure for rotating said blower tube during the sootblowing operation, and means for retracting said blower tube from said axially projected position upon completion of the sootblowing operation.

2. In combination with a boiler having a fire-box, a fire-wall surrounding said fire-box, and water tubes within said fire-box; a sootblower for removing combustion products from the outer surtace of said water tubes, said sootblower comprising a stator assembly mounted on said fire-wall, a bearing tube forming a part out said stator assembly, a movable assembly mounted for axial and rotary movement within said stator assembly, a blower tube housed within said bearing tube and forming a part of said movable assembly, a fluid outlet in said blower tube a firewall surrounding said fire-box, and water tubes 6 adjacent one end thereof, means for feeding fluid under pressure to said outlet wherein the means for feeding cleaning fluid to said outlet comprise a cylindrical chamber forming part of said stator assembly and with the interior of which the bore of said bearing tube is in communication, and means for connecting said chamber to a source of cleaning fluid under pressure, said stator assembly including acasing having exhaust ducts formed in it which extend from said cylindrical chamber to a clearance space between said bearing tube and said blower tube, means responsive to said fluid under pressure to impart axial movement to said movable assembly to project said blower tube outwardly from said bearing tube during the sootblowing operation, turbo-drive means responsive to said fluid under pressure (for rotating said blower tube during the sootblowing operation comprising a piston axially movable inside said cylindrical chamber, an impeller head rotatably mounted in said piston, and means [for directing pressure working fluid to said impeller head, and means tor retracting said blower tube from said axially projected position upon completion of the sootblowing operation.

3. In combination with a boiler having a fire-box, a fire-wall surrounding said fire-box, and water tubes within said fire-box; a sootblower for removing combustion products from the outer surface of said water tubes, said sootblower comprising a stator assembly mounted on said fire-wall, a bearing tube forming a part of said stator assembly,a movable assembly mounted for axial and rotary movement within said stator assembly, a blower tube housed within said bearing tube and forming a part of said movable assembly, a fluid outlet in said blower tube adjacent one end thereof, means for feeding fluid under pressure to said outlet wherein the means for feeding cleaning fluid to said outlet comprise a cylindrical chamber forming part of said stator assembly and with the interior of which the bore of said bearing tube is in com munication, and means .for connecting said chamber to a source of cleaning fluid under pressure, means responsive to said fluid under pressure to impart axial movement to said movable assembly to project said blower tube outwardly from said bearing tube during the sootblowing operation, turbodrive means responsive to said fluid under pressure for rotating said blower tube during the sootblowing operation comprising an impeller piston iixedly mounted on the blower tube and rotatably and axially movable inside said cylinder chamber, and means for retracting said blower tube from said axially projected position upon completion of the soot-blowing operation.

4. In combination with a boiler having a fire-box,

within said fire-box; a sootblower for removing combustion products from the outer surface of said water tubes, said sootblower comprising a stator assembly mounted on said fire-Wall, a bearing tube forming a part of said stator assembly, a movable assembly mounted for axial and rotary movement within said stator assembly, a blower tube housed within said bearing tube and forming a part of said movable assembly, a fluid outlet in said blower tube adjacent one end thereof, means for feeding fluid under pressure to said outlet wherein the means for feeding cleaning fluid to said outlet comprises a cylindrical chamber form-ing part of said stator assembly and with the interior of which :the bore of said bearing tube is in communication, and means for connecting said chamber to a source of cleaning fluid under pressure, means responsive to said fluid under pressure to impart axial movement to said movable assembly to project said blower tube outwardly from said bearing tube during the sootblowing operation, turbodrive means responsive to said fluid under pressure for rotating said blower tube during the sootblowing operation comprising a piston axially movable inside said cylindrical chamber, an impeller head rotatably mounted in said piston, and means for directing pressure working 7 fluid to said impeller head, and means for retracting said blower tube from said axially projected position upon completion of the sootblowing operation.

References Cited in the file of this patent UNITED STATES PATENTS 11,167,766 Linaker Jan. 11, 19116 1,450,957 Handoll Apr. 10, 1923 1,717,986 L-ieubau June 18, 1929 8 Snow et: a1 Mar. 8, 1938 Weeks Nov. 24, 1942 Hibner et al May 18, 1943 Thomas May 30, 1944 Schueler et a1. Sept. 15, 1959 Singleton Nov. 1, 1960 FOREIGN PATENTS Australia Nov. 3, 1927

Claims (1)

1. IN COMBINATION WITH A BOILER HAVING A FIRE-BOX, A FIRE-WALL SURROUNDING SAID FIRE-BOX, AND WATER TUBES WITHIN SAID FIRE-BOX; A SOOTBLOWER COMPRISING A STATOR ASSEMBLY MOUNTED ON SAID FIRE-WALL, A BEARING TUBE FORMING A PART OF SAID STATOR ASSEMBLY AND EXTENDING INTO SAID FIREBOX AND THROUGH ONE OF SAID WATER TUBES, A MOVABLE ASSEMBLY MOUNTED FOR AXIAL AND ROTARY MOVEMENT WITHIN SAID STATOR ASSEMBLY, A BLOWER TUBE HOUSED WITHIN SAID BEARING TUBE AND FORMING A PART OF SAID MOVABLE ASSEMBLY, A FLUID OUTLET IN SAID BLOWER TUBE ADJACENT ONE END THEREOF, MEANS FOR FEEDING FLUID UNDER PRESSURE TO SAID OUTLET, MEANS RESPONSIVE TO SAID FLUID UNDER PRESSURE TO IMPART AXIAL MOVEMENT TO SAID MOVABLE ASSEMBLY TO PROJECT SAID BLOWER TUBE OUTWARDLY FROM SAID BEARING TUBE DURING THE SOOTBLOWING OPERATION, TURBO-DRIVE MEANS RESPONSIVE TO SAID FLUID UNDER PRESSURE FOR ROTATING SAID BLOWER TUBE DURING THE SOOTHBLOWING OPERATION, AND MEANS FOR RETRACTING SAID FLOWER TUBE FROM SAID AXIALLY PROJECTED POSITION UPON COMPLETION OF THE SOOTBLOWING OPERATION.

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