US2486585A

US2486585A - Rotary retracting soot blower construction

Info

Publication number: US2486585A
Application number: US643055A
Authority: US
Inventors: Harry E Brelsford
Original assignee: Diamond Power Specialty Corp
Current assignee: Diamond Power Specialty Corp
Priority date: 1946-01-24
Filing date: 1946-01-24
Publication date: 1949-11-01
Anticipated expiration: 1966-11-01

Description

Nov. 1, 1949 H. E. BRELSFORD 2,486,585

ROTARY RETRACTING 500T BLOWER CONSTRUCTION 2 Sheets-Sheet 1 Filed Jan. 24, 1946 up wpu ,z

FE: IM'ENTOR.

' Nov. 1, 1949 H. E. BRELSFORD ROTARY RETRACTING SOOT BLOWER CONSTRUCTION Filed Jan. 24, 1946 2 Sheets-Sheet 2 Patented Nov. 1, 194.9

ROTARY RETRACTING SOOT BLOWER CONSTRUCTION Harry E. Brelsford,

Birmingham, Micln, assignor to Diamond Power Specialty Corporation, Detroit, Mich., a corporation of Michigan Application January 24, 1946, Serial No. 643,055

12 Claims.

The present invention relates to improvements in soot blower construction.

One of the primary objects of the present invention is to provide an improved soot blower construction which is particularly adapted for use in the hottest part of the furnace and which is so constructed and arranged so as to increase its life.

A further object of the invention is to provide improvements in soot blower constructions of the type mentioned in which the blower is projected into the furnace only during the blowing operation and is protected in a retracted position when not operating.

Another object of the invention is to provide improvements in soot blower constructions of the type mentioned which will permit making a securely sealed joint where the blower enters the furnace wall, thereby preventing leakage of gases from the furnace outward or the leakage of air from the outside into the furnace.

Another object of the invention is to provide improvements in soot blower constructions of the type mentioned in which the traveling member is securely held so that all strain against this traveling member is restrained by means rigidly related and so as to relieve the communicating member from all strain.

Another obiect of the invention is to provide improvements in soot blower constructions of the type mentioned in which the traveling member is restrained until it reaches the desired travel and then is released for any desired number of rotations so that the particular cleaning cycle may be followed.

A further object of the invention is to provide improvements in soot blower constructions of the type mentioncd in which there is provision for accessibil ty to the valve without interference to the piping.

'Another object of improvements in the soot blower constructions of the type mentioned which will permit ready operation of the valves against high pressure through relat vely slight effort on the part of the motive means of the blower itself.

Other objects of the invention will become apparent from the following specification, the drawings relating thereto, and from the claims hereinafter set forth.

In the drawings, in which like numerals are used to designate like parts in the several views throughout,

Fig. 1 is an end elevational view of a soot blower construction embodying features of the present invention;

Fig. 2 is a cross-sectional view, with parts in elevation, taken substantially along the line 2-2 of Fig. 1 and showing the construction in its relationship to the furnace wall;

the invention is to provide Fig. 3 is a cross-sectional view taken substantially along the line 3-3 of Fig. 2; and

Fig. 4 is a cross-sectional view taken substantially along the line 4-4 of Fig. 2.

It is frequently desirable to place soot blowers on the sides of boilers or furnaces so that they may project into the hottest part of the combustion space in order to direct the cleaning fluid onto the underside of the generating tubes, or other parts of the boiler, and where the location is so hot that the blower cannot remain in the furnace but must be retracted as soon as the blowing medium is discontinued. There are various types of such blowers, some which have very long travels, up to twenty feet, and others that require much less travel when it is desired only to clean heatin surfaces close to the urnace walls. The present invention is directed to the latter type and has'a travel of approximately twelve inches forward toward the boiler from its retracted position. This is sufiicient to retract the nozzle into the boiler wall space where it is protected from the heat while it is inoperative and yet allows it to project sufficiently into the combustion 'space so as to efficiently direct the cleaning fluid onto the surfaces of the boiler to be cleaned.

Because of the nature of the service, it is desirable that the cleaning fluid b turned on automatically as soon as the nozzle reaches its maximum projection and before it becomes appreciably hotter so as to endanger its life. It is therefore necessary that such a head be automatically valved in order to protect it from the heat. as well as from th standpoint of efiiciency in use of the cleaning medium. Such a head may be either manually or power controlled, and in either case it is desirable that the traversing motion be fairly rapid to conserve time as well as effort, because when power controlled by a power motor, the speed is fixed and the time interval of traversing becomes a definite, fixed interval and becomes important where thereare a great many units on aboiler to be operated in a given time. The construction of the present invention thus provides a head with the necessary travel, with the means for rapidly producing this travel, and of a rugged. construction which permits maintenance of rigidity and relative position while blowing. The construction of the present invention also lends itself either to manual or power operation.

Also, in general, the construction of the present invention is one which permits making a securely sealed joint where the blower enters the furnace wall and prevents leakage of gases from the furnace outwardly or from the outside inwardly. The projecting element has a smooth, uninterrupted exterior which permits of a packed joint to accomplish this. Furthermore, when fully exnot impose'any strainpIr-the telsc'opic-arrangement of the two tubes with consequent damage to the packing which seals the joints between the two tubes. Also, a rigid construction-is-provided.i

which takes the reaction forces when the news ing medium is being discharged. Furthermore, inasmuch as steam pressuresareccntiiiuahy iricreasing, it is becoming more" andinore'niflicultWPf" to directly open a valve under high 'pressure'because of the excessive force reqniredandnthereaw fore, according to the present invention, a self-- opening valve is provided. which is controlled by r a pilot valve operating thi'ough the medium of an unbalanced piston'w Tli'e blohving medium visliiitroduced'to the head structuretransversely of the" valve axis, ascompared'to" *ax-ia'1ly thereof, and it is, thereforewnot necessary" tci disturb the piping connections-'tmthis head for acc fohregriridirig, or other attentions- Referring *to -th drawings; the blowitnghead is generally-indicated ate-"I and is adafpted- 'to be mounted to the exterior surface of a furnace wall adjacent 'an' opening communicating with the zrw in'terio'r thereof, in' th' usual-Way. The furnace wal-l (not shown) 'hasan opening therethrough"= which communicates "with' the' combustion space within the furnace, and iii *the' present" instance bears-'to close communication between chambers" I u 4 and'-5."'- VVhenthe valve 9 ism'ovedewayfrom" the valv'e'seat'8,communication is establ'is'hed'be-.:-- tween'chambe'rs 4 and 5.

Valv'e'disk 9 is mounted 'on a stem I 0, and such a pistorrl I by-means ofa 'loclrwasherdz and a lo'ck nut I3 The ldoseness is between the periph-"- ery'of the" stem I and the "opening throughthe" locknut sothat' there'may be nobinding-in move mentof'the plunger? The locknut i3" is"secured-' against'locsening bymeans'of a locking disk 'I4i I The stem" Ii] extends througha central aper ture'in disk '9, and' such valvedisl:*se'ats" on-"a tapered shoulder-1 5' on the valve rod I0 and isground to a tight'joint on'thshoulden" The in-"- termediate 'portion'of thevalve" stem-"is reduced" and "threaded ,-"and-lock nuts- I6 are received on th--threaded=portion adjacent the upper fa'ceofthe valvediskw so that' the valvedisk 9 is' m'oved in either direction -du'e- *to th'e 1 engagement "of" shouldeiwm or the undei lolzk nut IGJ-as the ca's'e may be. The lock nuts may be adjustabl y"posi ticiied-'-'bn th'e threadedportionso thatany: desiredfidegree of freelininizor' slight ilost motion-- masabe impartedto thetdiskd.J

The 'upper and: reduced:=end-- ofnthe: valve stem? I 93 iisi indicatetl-at I i ancb'is guided in :a .gu-ide bushing. I 8 which visithise'aded:thirou'gh'ia threaded. opening .initlre'. castingtcat.the ltop rm-chamber. 4 imzaxiai:.ialtgnmentiwithzithez.vahientstemc. Thea A laterally'extending A throttling diSkZB is threa'dably mounted on"- guide bushing I8 is vented as indicated at I9 so as-itoprevent.compression'ofth.blolwirigimedium izi'thespace between the-er-id-of the valve stem and the end of the guide passage.

Piston I I is reciprocably mounted within a bore 20....formed imthe-casting 3 and communicating thr'oughfthe' lower side with chamber 5. An end plate 22 is bolted to the lower end of the casting adj'acent tli'e=bore -:2IIby means of bolts 23. The pistdr1I I is 'zforcedfiipwardly, or to its valvecldsing positib'n,b$ means of a compression spring 24 Sofia/S1130 seatlthezvalve disk 9 against its valve seat. A stop rod 25 is mounted centrally on the endpla'tefiz and projects upwardly within the bore 29 so as to limit thedownward movement of th= piston- I I, togetheiewvithithex'operatingz' parts connected thereto. Theiipistom'l I1 isznot azpenrfectly tight fit withinith'et bore;:itibeing.:intended that'thre'would besome' leakagefpastithis piston".- into th'e' bore 207 sori'lha'tuthere will. .be equalization-n offluid pressure between' chamber?!) and flth'eie chamber formed by "bore- 291 The particularaz: function of this will be more apparent fromua later de'scrintiom the bushing I8 within the chamber 4 'and adja cent the top edgecf valve member'B. B37- adjustingthe orifice disk-' 25 -on *the member HiQ- any desired clearance between itself and theexit sid'eofth'e valve seat 8 may "b'provideii so' astogive the desired throttling of the --'blowin'gmedium when "pressure on the discharge? side of-the valve isto be less thanthesupply pressure. The -pe'-"-- riphery of the disk26 is fo'rm'ed'withdepressions at spaced'intervals therearoundjandit maybe secured in any positionby'means of'a stopscrew" 2'! (Fig. '1)' .whichextendsiwith'in chamberfl and the end of which projects .with'inone of 'the I depressions in the peripher-yof the disk'26'j The casting 3 "is' formed with cleaning fluid"? passageway28, the end of whichis'in' open communication with chamber 4. The outlet endcom municatesthrough a horizontal opening 29 'foi'med in a fla'ngeportion 3D"of.thecasting-= A. bracket. 3 l=- isconnected to the. opposite. end of thecastingby means ofcap screws 32 and .ter-f minates in upwardly-.- extending and laterally: spacedprojecting,portions. .33 and. 34'.-'

The entire blowing unit I is mountedntorthea exterior surface/0f the furnace -wallagainstw-the usual wall. box fitting by bolts extending through the-flange ofuportion 34a 7 I In-general,- the projecting means inclu'des a a pair of telescoping members, the exteriorione of which has a blowing. nozzle-I 35- connected-t0. the

end thereof. Such telescoping-members: are indi-icated-at--36 andB'Ia Member-:35Fis'a tubul-an meme'sber;.-circularr in-rcross-zsection', and havinga thread: 38 X formed x'on' the outsidewsurfa'ce intermediate f the ends thereof. Theleft-handend'ofrmemberr -3 6' is received within opening :3 9 formed in'rfiange 39,*and packingdmis disposed be'tweennthe outer. surface of member 36' and the inner: surfaoemfi" opening 39. The tube 36 is secured' agalnst-axiai movement-by-means-oft a thrust bearing. II-.1 The thrust bearing 4 I? is mounted beiazveen-"a flangedmember 42, which is secured to flange 39*bymean'sq of bolts? 43, and-ran annularzmemberr 44. The

fiangemember. 42 hasan inwardly-extending an nular flange 45 which engages the outercsuriace ofrthe outerbearingracer: Memberi- 44 hasfian axially directed 'annularfiange 46 which engages. the. adjacent face of therinneribearingrace. Then inner end of packingll lflrabuts .againstia bearing:

shoulder in casting 3 adjacent opening 29. The

opposite end of the packing abuts against a shoulder flange on member 44 which is telescopically received within opening 39 of flange portion 30.

A driving member 48, in the form of a pulley in the embodiment illustrated, has a hub portion 49 within which the tubular member 38 is received. Such member 48 is secured to the member 36 by means of screws 50, so that the member 36 rotates with the driving means 48. The lefthand end of the hub portion 49 telescopically receives thereon the bearing races of the thrust bearing 4|. The outer bearing race abutting against a shoulder formed on the hub 49, and the inner bearing race is secured in place by means of a snap ring 5|. Since tubular member 36 is fixed to member 48, which in turn has the thrust bearing axially fixed with respect thereto, and since the flange 45 of the member 42 axially fixes the thrust bearing to the flange 30 of casting 3, it will be evident that the member 36 is held against axial movement, but may rotate with respect to casting '3. p

The right-hand end of the tubular member 36 is supported within the telescoping member 31. Such end of member 36 is reduced and has a packing 52 embracing the reduced end and held in place by bearing rings 53 and 54. Bearing ring 53 abuts against an adjacent shoulder formed in member 36, and ring 54 is held in place by means of a snap ring 55. Axial and rotative relative movement between members 36 and 31 is thus permitted.

Member 31 is circular in cross section and has a smooth, uninterrupted, exterior surface. It projects through an opening 56 formed in bracket portion 33 and also projects through an axial opening in bracket portion 34. The end of member 31 is threaded and has the nozzle 35 threaded thereto. The member 31 is adapted to be moved within the furnace to its projected position and retracted therefrom, to the position shown in Fig. 2, so that the nozzle 35 is disposed within the opening in the furnace wall when the blower is not operating. The right-hand end of member 31 is guided by means of a guide bushing 51 which is mounted within flange portion 34.

Sealing means 58 embrace the tubular member 31 and are disposed between the exterior surface of the member 31 and the adjacent wall of the opening through portion 34. The sealing means abut against a shoulder formed on an inwardly directed annular flange 59, and the opposite end of the packing is held in proper position by means of a packing gland follower 66. Gases from the furnace, therefore, cannot escape past the packing 58, nor can air enter the furnace from the outside past packing 58, while the member 31 is free to be moved to and from its projected and retracted positions.

The opposite, or left-hand, end of member 31 is fixed to the hub of an actuating member 6|, as by a weld 62, for example. The actuating member 6| has a disk portion 63 and a hub portion within which the tubular member 31 is received. The hub portion also has an annular, finished portion 64 which is adapted to be received within opening 56 and bear against bushing 65, within opening 56, when the tubular member 31 is extended to its projected position. Since portions 33 and 34 are spaced from each other, it will, therefore, be appreciated that when the tubular member 31 is extended to its projected position, it is supported within spaced bearings so that the projecting end of the nozzle is rigidly supported and does not cause undesirable loads on the operating means. I

The actuating member 6| has an annular member 66 fixed thereto by means of screws 61, and

such member 66 has a projection 68 formed on the inner surface thereof which is received within the thread '38 and provides a follower nut to cause axial movement of the member 31 when member 36 is rotated.

The member31 is restrained against rotative movement until it reaches its full, extended position, "at which time it is released so that it may rotate to effect the blowing operation. This is accomplished through the interrelationship between disk member 63 and a pivotally mounted bar 69. The disk 63 has a notch 10 formed in the periphery thereof which is adapted to receive the rod 69 therein. When the rod 69 isengaged within the notch 19 and the rod is held against movement, the disk 63 cannot rotate, as one of the walls of the notch will abut against the rod 69. The rod 69 extends axially of tube 31 so that the tube 31 and member 6| may move axially, even though they cannot rotate until a particular position is reached.

The rod 69 has depending pivot arms 1| fixed thereto which in turn have pivot openings therethrough. A pivot rod 12 is mounted on upwardly directed lugs 13 formed in the casting 3 and serves to pivotally mount the rod 69. The righthand end of rod 12 projects within an aligned opening 14 formed in bracket 3|. The rod 69 is normally urged to its upper position by means of a spring 15 which is wound around rod 12 and has one end thereof bearing against the rod 69 and the other end thereof fixed by abutment against the adjacent surface of casting 3. Viewing Fig. 3, the spring acts to pivot the rod 69 in a clockwise direction.

The tendency of the action of member 36 as it rotates is to turn the disc 63 in a clockwise mally projects, the recess being defined by rear-' wardlyextending projections 18. 19 formed integrally upon the stop member. Projection 16 prevents pivotal movement of the bar 69 in the indicated direction during advancing movement of the nozzle and until the projection 18 is moved out of the way by bodily forward movement of the stop structure, which movement is induced by the front face of cam disc 63. The forward end of the rod 69 then swings across and lies in facing relation to the adjacent rear end face of the projection 18 when the rod is pivoted to the position shown in broken lines in Fig. 3.

The stop 16 is formed with a notch 89 in the lower edge within which the pivot rod 12 is received. This connection between the stop 16 and the rod 12 prevents rotative movement of the stop 16, but permits axial movement thereof along rod 12.

The stop 16 has a sleeve 8| fixed thereto which is slidably received within an axially-aligned opening 82 formed in bracket 3|. A compression spring 83 is disposed within the opening 82, and one end of the spring abuts against the bottom of the opening and the opposite end abutsagainst a pin 84 which is fixed to member 16. Thus, the spring 83 normally urges the stop 16 toward the rear or left (viewing Fig. 2).

The manner in which the stop 16 is moved to 7 tssout-ni-the'way :positin:.'will:.be: described. in. greater detail hereinafter.

The pivoting-of the-r d .69.;and the len h f the.;;t imethat ;,it i$;jh8ld,1 in; its =piyoted1 position cnntrolsrthe:v opening rof'valvey 9, and therefore the-introduction: ofthe. cleaning medium through h .nezz einto th imm nse. The pivotin of the nod-r69- controls theoperation 01 33; pilot valve 85 which is mounted on casting. 3. The. pilot valve is formed; with anv inner T'chamher and a alves atflfi. ta disk'val-ve 81 s d sposed w th n heeval ve chamh nandzisnorma ly urged towa d the-se 6wby'meansof. awsprine .8 h al has a, stem-89; which extends upwardly through a;pacl ed: epening-inthe top of valve, body 85,. to a. position under an actuating arm 90. v The valve. 8.5.;ia-laterally ofiset. from the axis of the pivot shaft; 12, and. the arm 90. is fixed to the pivot rod 6% so that as the pivot rod pivots, as shown infig. 3,,the, actuating arm- 90 engages the upper end otstem 89, and depresses the stem to open valve 81'. '.The chamberzwithin. the valve above the -valveseat, .is .vented toe the atmosphere through an, opening 92.. .I'he chamber within the valve body on the underside of the; valve 8'l..is connectedthrough, aconduit 93 with an opening 94, through- .end. plate. 22. Opening 94 communicates withthe .chambeigformed by bore under plun er H.-

.The. wheel 48. maybe turned either yhand. or. it. may, bemotor-drive ...I m y einthe form 0t apl ll yvor a chain. spro ket so .that .it m y be turnedby. hand- .In the pperation of he devi e. assumin h th membe Ltoe therwi h the n zzl is n t retracted. p si i n. he valve 91 e the cleanngfl anno pas intocharnh 4. a d. gh

passageway .28 into and through the hollow interior of members 36 and 3.! and nozzle 35. When the valve 9 is opened it will, ofcourse, be understood. that the fluid follows. this path andis discharged through the openings in the nozzle head into the furnace and against'the surfaces to. be cleaned. "Upon rotationof wheel 48, either, by hand or motor, the member 36, is also rotated. Therelationship between thread 38' and nut 68 will cause the nut; together with members 6L and 37, t travel axially of member 36 toward the projected position. At this time, the stop 16 is in its restraining-position shown in Fig. 2, so that the rod' 69 cannotpivot', andsuch rod is received within the notch-10 with one wall of the notch bearing thereagainst. This continues until the disc 63 reaches the position to abut against the facing side of stop 76. Continued axial movement of member 31, together with member'fil, causes thedisc 63 to force the stop T6to the right against spring 83. It is forced to that position until the end of-rod 69 is released from abutment against the one side of recess 71 and is free from projection l8. As soon asthe rod-'69 is freed so that it may pivot disc' .63. is also free to turn and during the-initial portion of=itsrotary movement. will cause'rodw69. to pivot aboutits pivot pin 12, as shown in Fig. 3, and cause depression of valverstem 89..so.- as: to vent. valve. 85. to, the atmosphere. *The underside of piston l I is at the same time vented to atmosphere through opening- 94andconduita93. As mentioned above, as soon as the pressureiunder piston H is vented to theatmosphere, thezfluid pressure within chamber 5-from the/cleaning mediumwill. instantly move' thaplunger downwardly: to open valve 9 and permit the passage. of: the :cleaningfluid into chamber- 4, passageway 28,-.anditoi the; cleaning nozzle-rthrough-members 1'36 and-31. The cleaning nozzle thereafter rotates. with: member; 31in re sponse tocontinued: turning of wheel 48 while the cleaning medium is passing through the openingstherethrough. The valve '85. will be held vented to atmosphere and the unnotched periphery- .ofdisc '63 r-ides.over the rod 69', holding it in its.inclined pilotevalve actuating position until notch? Ill-againreaches-a position so that the spring 15..may.return the rod to its upper position' withinthenotch. Continued forward rotationofthe disk (in the same directionas the wheel-'48 was turned to project the nozzle) is effective tomaintainbar 69 and arm 99 cocked and valve 8'! open throughout such part of each such-forward-revolution as bar 69 is out of cam notch 10-,- and blowing" may thus be continued for any number of revolutions, although during each such revolutionblowing steam is only discharged while the bar is cooked by the higher parts of 0am disc 53, and is'stopped when the bar is raised intothe notched portion of the cam by the spring 15. The time in which the actual blowing takes place dependsupon the length of the cut away or, notched portion *1 0 of the disc, being shorter as such notch is lengthened peripherally. It is illustrated in the drawings of a very small length, but it may extend around the periphery of the disk up to, for example,

It will be understood, of course, that the driving member 48 is rotated at. a. more or less uniform rateand, as soon as the rod 69 is not supported by the periphery of cam 63, the spring 15 will swing the rod in a counterclockwise.direction on its pivot pin .1 2, as viewed. in Fig. 4, or in a clockwise direction from .the broken line to the full line position asshown in Fig. 3; This movement of the rod. .69 releases the pressure. of the actuati s arm .90 from. the valve stem 89, thus. permittingthespring. 8.1,.to. close the pilot valve 85, and thus themain .valve. .9. In this wise, itis seen that the. peripheral length of the. notch 10 determines the rtion, of a revolution of the cam 63 duringwhich. blowing fluid is not discharged.

Reversal. ofrotation ofthe member .48 will cause retraction of member '76, togetherwith disk 63. This will permit the, stop 16 to move back to the Position showndmFig- 2, in which position the rod 69,.cannotpivot afterit has once come back into slot. 10. I Continued rocking of the rod 69 in a reverse ,(clockwise) direction past a vertical position, asshownin full lines in Fig. 3, is prevented by-the-projection 19 on stop 16 engaging against the forward arm H, such rocking move ment being in a counterclockwise direction as illustrated in Fig; 4, whichis a view taken looking in a direction opposite to that of Fig. 3. Projection- 19 is longer than projection 18 so that it always overlaps the bar 69 and front arm ll as shown in Fig. 2. Further reverse rocking movement of therod 6'9-beyond the'vertical position being restrained, it follows that further rotation of cam 63 is prevented, when .abutted by the wall at thefipposite end,of. notch 70. from the end which serves to initially cockthe bar. Thereupon, further reverse rotation of the driving member 48 causes relative. rotation between the threaded tubeili ,andthe blowerelement 31, which will cause retraction. of. the blower element. Qontinued rotation of, the. wheel 48 in the reversed directionwill efiect movement of member 31 to its. fully retracted position shownin Fig. 2. When the .valve 8,! .isclosed, the above-mentioned leakae past. pis on twi11.--equa1iz.e.the pressures on both sides thereof so that the spring 24 may act with ease to close valve 9.

What is claimed is:

1. A soot blower construction comprising a housing, means providing a fluid inlet chamber within said housing, valve means controlling the flow of fluid through said chamber, a fluid passageway within said housing communicating with said chamber, an externally threaded tubular member mounted on said housing and communicating with said passageway, another tubular member adapted to have a nozzle mounted thereon telescopically embracing said threaded tubular member and mounted thereon for axial and rotative movement with respect thereto so that it may move to projected and retracted positions, said another tubular member having a smooth, uninterrupted exterior surface, means connected to said another tubular mcmber and engaging the thread on said threaded tubular member to effect axial movement of said another tubular member upon rotation of said threaded tubular member, an actuating member connected to said another tubular member for movement therewith, means to effect rotation of said threaded tubular member, movable means connected to said actuating member to restrain rotation of said another tubular member until it reaches its projected position, means to prevent movement of said movable means until engaged by said actuating member when said movable means is released for movement, and means responsive to the movement of said movable member to efiect actuation of said valve means.

2. A soot blower construction comprising a housing, means providing a fluid inlet chamber within said housing, normally closed valve means controlling the flow of fluid through said chamber, a fluid passageway within said housing communicating with said chamber, an externally threaded tubular member mounted on said housing and communicating with said passageway, another tubular member adapted to have a nozzle mounted thereon telescopically embracing said threaded tubular member and mounted thereon for axial and rotative movement with respect thereto so that it may move to projected and retracted positions, said another tubular member having a smooth, uninterrupted exterior surface, means connected to said another tubular member and engaging the thread on said threaded tubular member to eifect axial movement of sa1d another tubular member upon rotation of said threaded tubular member, a disc member having a notch in the periphery connected to said another tubular member for movement therewith, means to efiect rotation of said threaded tubular member, a pivotally mounted bar engageable in said notch and extending longitudinally of said another tubular member to restrain rotation of said another tubular member until it reaches its projected position, means to prevent pivotal movement of said bar until engaged by said disc member when said bar is released for movement, and means responsive to the movement of said tubular member to open said valve means.

3. A soot blower construction comprising a housing having a passageway and a fluid inlet to the passageway, valve means controlling the flow of fluid to said passageway, an externally threaded tubular member rotatably mounted on said housing and communicating internally with said passageway, a second tubular member adapted to have a nozzle mounted thereon tele- 10 scopically embracing said threaded tubular member and mounted thereon for axial and rotative movement with respect thereto, said second tubular member having a smooth, uninterrupted exterior surface, means connected to said second tubular member and engaging the thread on said threaded tubular member to effect axial movement of said second tubular member upon rotation of said threaded tubular member, means to effect rotation of said threaded tubular member, keying means to restrain rotation of said second tubular member until it reaches one end of its travel, including a common keying and valve actuating element movable concurrently with said second tubular member, and means for actuating said valve in response to movement of said element.

4. A soot blower construction comprising a housing having a passageway and a fluid inlet to the passageway, valve means controlling the flow of fluid to said passageway, an externally threaded tubular member mounted on said housing and communicating internally with said pas-' sageway, a second tubular member adapted to have a nozzle mounted thereon telescopically embracing said threaded tubular .member and mounted thereon for axial and rotative movement with respect thereto, said second tubular, member having a smooth, uninterrupted exterior surface, means connected to said second tubular member and engaging the thread on said threaded tubular member to effect axial movement of said second tubular member upon rotation of said threaded tubular member, means to effect rotation of said threaded tubular member, keying means to restrain rotation of said second tubular member until it reaches one end of its travel, including a common keying and valve actuating element movable concurrently with said second tubular member, a longitudinally disposed key interengageable with respect to said element to hold said element and the second tubular member against unwanted rotation during axial movement of the latter, latch means normally holding the key against lateral movement but releasable by said element as the second tubular member reaches the end of its axial movement, and means responsive to lateral movement of the key for actuating the valve.

- 5. Means as set forth in claim 4 wherein said element comprises a disc secured to the second tubular member and having keying portions and camming portions engageable with said key and also having latch actuating portions engageable with said latch means.

6. Means as set forth in claim 4 wherein said element comprises a disc secured to the second tubular member and having peripheral keying portions and camming portions engageable with said key and also having latch actuating end face portions engageable with said latch means.

'7. A soot blower construction comprising a housing having a passageway therein and a fluid inlet to the passageway, a valve for controlling the flow of fluid to said inlet and passageway, a tubu-- lar member rotatably carried by said housing and communicating internally with said passageway and having external driving thread portions thereon, a second tubular member surrounding the first tubular member and longitudinally slidable and rotatable with respect thereto, driven portions fixedly secured with respect to said second tubular member and engaging and drivable by said thread portions, shiftable keying means having a keying position in which it is adapted to prevent unwanted rotation of said second tubular member during longitudinal travel of the latter, whereby said second tubular member may be driven longitudinally in response to rotation of said first tubular member, means supporting said keying means for independent shifting movement to and from keying position, means normally holding the keying means against such shifting movement including a releasable latch for maintaining said keying means in said keying position and which, when released, permits shifting of the keying means to a, non-keying position and resultantly permits rotation of said second tubular member.

8. Means as set forth in claim 7, including a valve actuating element actuatable in response to release of said keying means.

9'. Means as set forth in claim '7 wherein said keying means comprises a laterally movable bar,

valve actuating means operatively connected to the bar and movable to actuate said valve in response to lateral movement of said bar out of the operative keying position, means to release said latch in response to attainment of a predetermined longitudinal position by said second tubular member, and a combined keying and camming element secured to and movable both longitudinally and rotatably with said second tubular member whereby said second tubular member is rotatable without longitudinal movement thereof, and whereby said bar may be moved laterally in response to rotation of said second tubular element after release of the-latch, and the valve is actuatable by such rotation.

10. Means as set forth in claim 9 wherein release of said latch permits lateral movement of said bar in one direction only, spring means urging the bar in the opposite direction to that in which it is movable upon release of said latch, said combined keying and camming element comprising a cam having portions adapted to extend beside said bar when the same is latched, and

12 having peripheral portions adapted to maintain the bar in laterally displaced position during at least a part of the rotation of said second tubular member.

11. Means as set forth in claim 9 wherein saint combined keying and camming element also carries a latch actuating portion for releasing said latch.

12. Means as set forth in claim 9 wherein said combined keying and camming element also carries a latch actuating portion for releasing said latch, and wherein release of said latch permits lateral movement of said bar in one direction only, spring means urging the bar in the opposite direction to that in which it is movable upon release of said latch, said combined keying and camming element comprising a cam having portions adapted to extend beside said bar when the same is latched, and having peripheral portions adapted to maintain the bar in laterally displaced position during at least a part of the rotation of said second tubular member.

HARRY E. BRELSFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,465,387 Bowers Aug. 21, 1923 1,773,801 Wilson Aug. 26, 1930 1,944,324 House et al Jan. 23, 1934 2,104,003 Schiefier Dec. 28, 1937 2,110,534 Snow et a1. Mar. 8, 1938 2,249,741 Bowers et al July 22, 1941 2,303,152 Weeks Nov. 24, 1942 2,351,117 Glinn et a1. June 13, 1944 FOREIGN PATENTS Number Country Date 305,875- Italy Feb. 18, 1933