US2366131A - Tube cleaning head - Google Patents

Description

Patented Dec. 26 1944 'UNITED STATES EATENTQFFIVCEY f TUBE CLEANING-HEAD Morril B. Spaulding Habana, Cuba ,Applicationlv farch 27, 1942, Serial No. 436,503

3 Claims. (C1.15--104.09)

The present invention relates to improvements in tube cleaning heads for removing scaleand other incrustations from the inner surfaces of the tubes ofboilers, heaters, condensers, evaporators and similar apparatus, and it is more particularly applicable to the cleaning of tubes which are composed of relatively soft metal, such as copper or bronze. i

The primary object of the invention is to provide a novel and improved tube cleaning head which is capable not only of removing rapidly and efficiently relatively hard and dense scale or incrustations from the interior surfaces of relatively soft metal tubes but is capable of doing so Without shaving, striating or otherwise damaging the metal and of imparting a burnished finish to the interior surface of the tube, so that no pits or other irregularitieswill be leftin the metal surface of the. tube to promote the subsequent accumulation of scale or other deposits thereon.

Tube cleaning heads having radial blades pressed outwardly to engage the inner'walls of tubes and effect a cleaning action by rotation of the head have been previously proposed, but such heads have not proven entirely satisfactory. In such previously proposed heads of this type which I am aware of, no means has been provided for centering the head in th tube or gauging the extent of outward movement of the blades, so

that the blades had a tendency to exert undue pressure at one side of the tube,and of shaving,

striating, and otherwise damaging themetal of the tube, especially when the tube is composed of copper or similar relatively soft metal.

i The present invention provides animproved cleaning head of this type which overcomes these objections and produces novel and improved results. According to the present invention, the head is provided with members which serve to center the head in the tube and to control the action of' the blades, whereby the blades are caused to act on theinner surface of thetube uniformly around its circumference, thus effecting thorough cleaning of the tube without undue pressure against anyone side of the tube, such as would shave the metal therefrom, and the cutting edgesof the blades are maintained par:

allel to thetube walls, thus insuring efficient action of the blades throughout their lengths and avoiding striating the metal of the tube, and by controlling the action of the blades and centering them within the tube, a burnishing action is produced on the inner tube surface which closes the pores of the metal and producesa smoothsur-Q face which minimizes adhesion of scale or other deposits thereon.

The preferred embodiment of the invention is shown in theaccompanying drawing wherein Figure 1 is a side elevation of the improved tube cleaning head; i i i Figure 2 is a central longitudinal section thereof; i Figure 3 is a transverse section taken on the line 33 in Fig.2; and i Figure 4 is a view of the body of the head wit the blades removed. Similar parts are designated by the same refer. ence characters inthe different figures. i

The improved tube cleaning head, in its preferred'construction, comprises a body I which is in the form of a solid cylinder having a suitable number, at least three, of radial slots 2 formed therein, four of these slots being shownin the present instance. These, slots extend in parallelism to the central or longitudinal axis of the head and are spaced equidistantly circumferentially thereof. A blade 3 is fitted loosely in each of these slots, these blades being freely movable radially intheir slots, the outer edge, of each blade being bevelled to provide a relatively sharp scraping or cleaning edge 4 extending throughout its length. The body of the head and theblades are composedof appropriate metal, and the body i may varyin diameter and length, and the blades may vary in length, radial width and thickness according to the inside diameters of the different 6 which is threaded removably on a screw-threaded stem 1 which projects axially from one end of the head and has an annular counter-bore 8 formed therein'toreceive the extensions 5 on the bladesadjacent to one end of the head, and a collar 9 which is threaded removably on a screwthreaded shank In which extends axially from the other end of thehead, said collar having an annular counter-bore II to receive the extensions 5 on theblades adjacent to that end of the head.

The blades maybe inserted into or removed from their slots while one or both the disk 6 and collar 9 are unscrewed or removed, and when these parts are screwed into their places, as shown in Fig. 2,

"55, they permit radialmovements of the blades in their slots but limit their outward movement and prevent displacement from their slots under the centrifugal force developed in the blades by the rotation of the head.

According to the present invention, the head the disk I2 having a sleeve l3 thereon which is internally threaded to screw onto the threaded shank Ill and abut against the collar 9 to lockit in place and provide a driving connectionfor the head, this disk l2 having a, screw-threaded stem outwardly with a force of the proper magnitude to effectively scrape and remove the scale or incrustation from the tube during the advance of the head through the tube, and during the retraction or'withdrawal of the head from the tube, the blades produce a burnishing action upon the inside surface of the tube, which closes the pores in the metal and provides it with a smooth finish devoid of pits in which scale forming substances might lodge, thus delaying the subsequent accumulation of scale oriincrustati'on; Each use of the head renders the inside surface of the tube denser, thus reducing the tendency of scale to adhere thereto.

As thedisks on the head maintain the outer scraping edges of the blades in parallelism with the'inside wall of thetube, maximum scraping l4 projecting therefrom for theattachiment .of.a

universal joint I5 which may be connected to a rotary steam or air motor for rotating "the cleaning head at an appropriatespeed. a

The disks 6 and IZ-are each of generally, circular form andxof asdiam'eter, about-p s of. an inch less than .theinside diameter of. the tube -to be cleaned, such as the tubewdesignatedX in Figs. 2 and 3,and the depth of the slots 2 andthezradial width of theblades 3 are so proportioned: that the diameter of said disks is greater than :that of the-circle in which the outer edges of thezbla'des lie when the blades are retracted to their inner most positions, or rest against :the inner ends of their radial slots. This feature oithepresent invention prevents assolid bearingwoffthesblades against any one :side of the tube :being. cleaned,

since each blade can move .into its.:s10t so that its outer edge is within theperiph'eries of the disks at the respective sides thereof, although all of the blades will float in a circle, the diam'eteriof which is greater than that of thediskst-fiandufl. Asithese disks are of"a diameternearlyequalIto 'thevinsi'de diameter of: the tubebeing cleaned, theywill center the'headin the tub'elwith'its axis parallel to that 'of;the"tube,' sosthattheiouter bevelled edges of theiblades will be held: parallel to-the inside wall of the tubexandswilltherefore act thereon uniformly throughout theinlength. The peripheries- 0f the idiskswlian'dil ZJaTe provided with" circumferentially spaced recesses wl fisand 11 respectively to afford free'vpassagewaysi'through which airiexhausted from-,athe ainmotor may 'ilo'w past the head and thus fcarry away the: particles of scale or. incrustation removed "from? the tube by the cleaning head, as whenitheuhead isxemployed'for dryycleaning :of'tubes EOr'fOI- thBflOW- of liquid which will-wash: :awayF suchiparti'cl'es when the head is' employedwforrwet cleaning Y1 The projections I a and I 9-intervening :lther' recesses provide ample bearing;surfacesziforthe smooth -rota tion'of the-head in thei-tube.

In iusingga xcleaning head' constructed asihere inbefore described, aiahead rofra:sizeoappropriate for the inside diameter 'offthe tuber-to be cleaned islcon'nectedby thesuniversalL-joint l5-'-=to an air motor orother' suitable :operatin'g meansand- 'in serted into one-end ofithe'i tube and driven at a speed of preferably about 6500 revolutions per minute. -Whilel therhead, lissb'einga of-driven; it is advanced to Y the other :end. ofith e ube,..the'- head removing the'sscale .or incrustati'on as itfadvan'ces,

after which the head isrwithdrawnifrom tlre tube.

Y virtue *of' the :freedom f:radialnmovement of the blades inithei-r slots,- theyareufcrced outwardly= by thescentrifug-alforce rde-veloped: by the high speed; rotation. or thecrheadgi theeouter' b'ev elled: edges of the: blades 'being itherebyzpressed capacity is attainedby the utilization of the entire length of the blades, which also minimizes 'the rateof wear of the blades, and furthermore,

the ends :of the bladescannot gou e into the metal and thus score, striate or'otherwisedamagelthe tube.-

Although tube cleaning heads constructedxin accordance with the present invention mayibe similar apparatus, they are especially adapted to meet the requirements in the cleaning of the copper tubes of evaporators or otherapparatus employedin sugar manufacture-in which'the de-' posits areof 'a ceramic nature and are hard and dense theimproved cleaning head enabling such scaleor incrustationto be: removed rapidly 'and without damaginglthe relatively soft metal composing the tubes, andimparting to theltubes a burnished or polished surface which inhibits the subsequent accumulation 'of scale. or incrustation.

'Since thepressure of the blades against the inside 'oi'the tube during the operation'zofi'the cleaning, head, is produced solely by=thelcentriiugal -=force developed in :the: blades by the rotation of the: head, and the action of .the' blades ion :the tube is controlled by the disks the :structur'euof the head-is notion-1y simple-but ethe- :pressurevex erted by, all, of the: blades is equal, and liftingaor shaving; of the metal-0f theltu-be is @ayoidedgand moreover, themagni-tudezof pressureof thezblades against the inside ottheutube in order to best meetdifferent requirements accordingqto dif- 'fe'rent natures ofv the scale orincrustation tov be removed, and ..to. effect the: burnishi-nggofl themside wall of the .tube, and .to. attain the maximum capacity, may be/readily variedby,appropriately varying'the speedof rotationuof the-head during the cleaning and burnishingl operation. As the body, and "disks and "the, arrangement .of the-slots for the blades- "of'th'e head. aresymmetrical, these parts'ofthe head "are balanced dynamicallyland as the blades are heldby, centrifugal fbrceagainst the inner surface of the tube beingfclaneddthere is" no obiectidnabl vibration .'during 4 the operation oftheclean'inghead. V

realmas my'invention':

1; A rotatable tube"cleaninghead.comprisingca solid substantially cylindrical body, 1 having threaded axial extensions, projecting, ram its ends and I formed with' 'radi'a'l circumferentially spaced "axially extending 'slots theinner ends of which areclosed, aset-nfbalanced blades freely movable radiaHy in said slots solely by centrifu gal force during rotation of "the head to "produce the pressure for removal of incrustations on-the inner-surface of the tubebe'ing cleaned ander-m: ited: in their inward radial movement by *the closed inner ends of the slots, said blades having straightbevelled outer edges which extend; longitudinally of the head, and concentric centering disks rigidly fixed on the respective axial extensions projecting from the ends of the body andengageable bythe ends of the blades to limit outward radial movement thereof and to maintain the outer edges of the blades in substantial parallelism with the axis of the head, said disks and the inner ends of the slots providing fixed abutments whereby the outer edges of the blades may lie ininner and outer circles, andsaid disks being of a diameter greater than the inner but less than the outer circle and engageable with the inner surface of a tube being cleaned to center the head therein and maintain the outer edges of the blades in parallelism with said tube surface and to confine rotation of the outer edgesof the blades to paths between said inner and outer circles, said disks having circumferentially spaced recesses in their peripheries for the passage of fluid.

2. A rotatable tube cleaning head comprising a cylindrical body, a plurality of blades symmetrically spaced circumferentially and freely movable radially between innerand outer fixed abutments, said blades havingbevelled outer longitudinal edges, and centering disks on the ends of the head concentric with said body and having circumferentiallyspaced projections on theirperipheries for engagement with the inner surface of a tubeto be cleaned, and having recesses; between said projections for thepassage of fluid,

said body and disks'being dynamically balanced. 3. A rotatable tube cleaning head comprising a solid cylindrical body having threaded axial ex-v tensions projecting from its ends and formed with radial circumferentially spaced axially extending slots closed at their inner ends, blades movableradially in said .slots and having bevelled longitudinal outer edges, a centering disk of greater diameter than said body threaded on one 1 of said axial extensions and cooperative with adjacent ends of the blades to limit their outward radial movement, a sleeve threaded on the other of said axial extensions and cooperative with the other ends of the blades to limit their outward radial movement, and a second centering disk of greater diameter than said body threaded on said other axial extension in locking engagement with said sleeve said disks being of a diameter to maintainthe outer bevelled edges of the blades in parallelism with the inner surface of a tube to be cleaned and to limit the outward radial movement of the blades toward said surface of the tube.

MORRIL B. SPAULDING.

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