Tube scraper

Oct. 22, 1935. η. j. forster 2,018,124

TUBE SCRAPER

Filed Aug. 30, 1933

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Patented Oct. 22, 1935

2,018,124

UNITED STATES PATENT OFFICE

2,018,124 TUBE SCRAPER Harry J. Forster, Chicago, Hl. Application August 30, 1933, Serial No. 687,399 13 Claims. (CI. 15—104.19)

My invention relates to cleaning devices, particularly adapted for scraping or cleaning the interior surface of cylindrical members, such as tubes. My device is especially adapted for 5 cleaning the tubes in boilers where the space available for manipulating the operating rod with which devices of the kind are used is limited. In such cases it is customary to use either flexible rods or multiple jointed rods made 10 up of several lengths swivel connected and sufficient in length to pass the cleaners through the tube being cleaned. With such rods it is difficult to urge the ordinary type of scraper through the tube on the push-in or insertion stroke, due 1.5 to the buckling of the flexible or jointed rod as a consequence of the pushing force required during the operation. This is true of all scrapers which are constructed for the purpose of cleaning the tube with the same adjustment of pres20 sure on the scraper members for both the pushin and the pull-out stroke.

The objects of my present invention are to provide a simple, effective, rugged and economically constructed tube scraper; to provide a tube 25 cleaner or scraper, which, when properly adjusted before insertion into the tube automatically applies the major effective pressure to the scraper members or scraper blades as they are known in the art, only on pull-out movement of 30 the device, and wherein a yielding spring tension is .applied to the scraper members automatically by the pull exerted on the device on the pull-out stroke; to provide a tube or flue cleaner having one or more adjustable expanding scraper ele35 ments, which are placed under spring or yielding tension on the pull-out stroke, but wherein the spring tension is automatically released by the force applied when the device is pushed into the tube; to provide a tube cleaner comprising 40 a ma.ndrel by which the device is pushed into or pulled from the tube, and a plurality of adjustable scraper members, the arrangement being such that the scrapers are closed by the force applied directly to the mandrel itself; to provide 45 a tube scraper or cleaner embodying a mandrel adapted to be pushed into the tube and to be pulled out of the tube and associated adjustable scrapers resiliency mounted with respect to the mandrel and wherein said scrapers are auto50 matically forced yieldingly outwardly under spring tension into contact with the walls of the tube by a wedging action occasioned as the tube scraper is pulled as a whole out of the tube on the pull-out stroke with relation to the tube;

and to provide a tube cleaner involving a man drel, a saddle mounted on the mandrel, and a plurality of adjustable scrapers connected to the saddle and adapted to be inserted into a tube and pulled out of the tube, together with spring means for applying resilient pressure directly to 5 the scrapers and cam means, adjustable by turning movement of the mandrel, for radially adjusting the scrapers and the spring tension.

Further objects of the invention are to provide a scraper device wherein means is provided to 10 automatically apply or release the spring tension on the scrapers by the longitudinal movement of the mandrel by employing the back and forward movement thereof involved in the pushin and the pull-out strokes of the cleaning oper- 15 ation; to provide a cleaner device wherein on the push-in stroke there is automatically effective a very light and yielding contact of the scrapers with the interior tube surface and the pull-out stroke is attendant with a strong elastic 20 pressure of the scrapers against the internal tube surface, which pressure is automatically applied on the pull-out movement or withdrawal stroke; to provide a clean-out device of the foregoing character embodying a mandrel having a 25 threaded portion and a nut adjustable therealong for adjusting the initial position of the scrapers relative to the inner wall of the tube and wherein the nut is provided with self cleaning means; to provide a scraper of the foregoing 30 type having means threadedly engaging the mandrel and adjustable by relative turning movement between the means and the mandrel; to provide a stop to limit movement of the mandrel with respect to the scraper members in one 35 direction, said means also functioning to apply the force exerted on the saddle to push the cleaner through the tube on the push-in stroke and to prevent dirt passing between the inner edges of the scrapers and the mandrel on the 40 pull-out stroke, and to provide another stop to limit movement of the mandrel relative to the scraper members in the opposite direction, said means also functioning to bear the strain of the force applied to the saddle to force the cleaner 45 through the tube on the pull-out stroke; to provide these and other objects which will be more apparent from a perusal of the following specification when taken in connection with the accompanying drawing, wherein: 50

Fig. 1 is a view partly in section of my improved cleaning device being inserted in a tube to be cleaned, wherein the scrapers are shown in the position they assume momentarily when they meet substantial resistance on the push-in 55

2,018,124 stroke (exaggerated for illustration). The normal position of the scrapers, however, when the device is inserted, is in very light contact with the incrusted surface of the tube.

Fig. 2 is a similar view showing the device operative on the pull-out stroke;

Fig. 3 is a cross section, showing certain of the details of the device.

Fig. 4 is a section on line 4—4 of Fig. 3. 10 Fig. 5 is a section on line 5—5 of Fig. 3.

Referring now to the details of the device and to the drawing, my improved tube cleaner or scraper is adapted to be attached to an operating rod such as previously described and com15 monly used in connection with tube scrapers for . inserting and manipulating devices of the kind into tubes for cleaning purposes. In the preferred construction of my device it embodies a coupling 2 adapted for threaded connections as 20 at 3 to any type or form of such rod as mentioned, for introduction of the device into a tube T, For the purpose of illustration the coupling is shown threaded to the end 4 of a multiple jointed or flexible rod.

The coupling which also· acts as a guide is preferably given a tapered formation as shown, to facilitate movement of the device through the tube on the withdrawal or pull-out stroke. The cleaner or scraper at its other end is likewise 30 constructed as will be hereinafter more evident, to permit its easy entrance to the tube on the push-in stroke.

The coupling 2 is securely fastened by threaded engagement to the mandrel, generally indicated 35 at 6. Pin 8 prevents relative movement of these parts, thereby preventing detachment while in the tube when the mandrel may be rotated for making adjustment of the scraper blades and thereby making the coupling and the mandrel 40 practically one piece.

The right hand portion 5 of the mandrel 6 adjacent to the coupling 2 is free of threads, and carries freely mounted thereon the saddle 26, while at its central portion it is threaded as at 45 10. The left hand portion 12 of the mandrel is likewise unthreaded and carries freely thereon the saddle 24, and is smaller in diameter than portions 5 and 10 to allow for the application of nuts 20 and 18. An expander nut 18 in threaded 50 engagement with portion 10 of the mandrel 6 is caused to travel back and forth over the threaded portion 10 when the mandrel is rotated since said nut 18 is held against rotation by the engagement of the slots 44 of its web 42 with 55 springs 38, the direction of travel depending upon the direction of the rotation of the mandrel. This nut IS is provided on opposite sides with threaded extensions 14 which are provided with cut-outs 16 at suitable portions around the cir60 cumference of the thread to permit the discharge of dirt and other matter, and thereby keep the thread 10 clean. The extensions 14 act as cutters for removing foreign matter as the parts 10 and 18 are relatively rotated.

In addition to the expander nut 18 the mandrel also carries a bumper nut 20, which is tightly secured thereon. As shown the nut 20 is threaded upon the portion 10 of the mandrel. The parts may be relatively fixed by a mutilation of 70 the engaging threads, by welding, or in any approved manner. This nut 20 serves for the purpose of first to provide a stop for limiting the movement of the mandrel to the left relative to the scraper blades, thereby governing the ex73 tent of the decamming or release action of the expand nut 18 on the springs 38. Second, it serves to engage saddle 24 on the push-in stroke to place any strain due to the insertion of the device through the tube directly on the mandrel, and it allows a ramming action against the 5 saddle 24 when the mandrel is worked back and forth. It also serves to practically close the gap between the scrapers and the mandrel to prevent scrapings from passing through on the withdrawal or pull-out stroke. In addition, there is 10 a stop nut 22, which threadedly engages the end of the mandrel 6 and acts as a stop against which abuts the hub or saddle 24, which is free to slide along the unthreaded portion 12 of the mandrel. This nut 22 serves a triple purpose. 15 It limits movement of the mandrel to the right relative to the scrapers, thereby governing and extent of the camming or expanding action of the nut 18 on the springs 38. It also serves to place strain due to the withdrawal of the device out 20 of the tube directly on the mandrel, and it allows a ramming action against saddle 24 when the mandrel is worked back and forth.

A plurality of scrapers 33, consisting of a shank braced by a web construction and having scraper 25 faces, preferably of general arcuate and sectional form as shown in Fig. 4, are provided. These scrapers are arranged with their lateral edges 2S in overlapping arrangement, whereby the outer circumferential edges 38 of the scrapers provide 30 a continuous circle of scraping cutting contact. Each of these scrapers is pivotally mounted by its shank as at 32 on a furcation 32' on the saddle 24, so that it shifts outwardly and inwardly toward and away from the inner wall of the tube 35 and relatively to the mandrel 6. The scraping face of each scraper is provided with furcations 34, through which passes a pivot pin 36 carrying one end of a flat spring 38 of leaf-like construction. The parts 34' of the furcations 34, by 40 acting as guides for the tube end, facilitate the insertion of the scraper blades into the tube from the left when the occasion arises as when the scraper has been passed completely through the tube. 45

The other end of the spring 38 is fastened rigidly by means of the screw 40 or other device to the hub 26. The expander nut 18 is provided with a web or plate 42 slotted as at 44 at the diametral points to provide a plurality of 50 grooves in which the spring members 38 rest. The web 42 with its. grooves operates as a cam to force the springs 38 outwardly and thereby put a yielding pressure in an outward direction on the scrapers when the expander nut 18 is thread- 55 edly actuated or is pulled by means of the mandrel to the right as viewed in Fig. 3. In addition, these grooves engaging the springs 38 prevent rotation of the expander nut 18. It will be understood that any number of springs can be 60 used, depending upon the number of scraper segments used. These springs are preferably made of flat spring material, but it will be understood that other shapes can be used, provided the shape does not interfere with .the hinged pivotal move- 65 ment of the scrapers 33.

A coil compression spring 46 is disposed between the saddle 26 and the coupling 2. This spring presses resiliently against the saddle 26 and the coupling 2 and the compression of the 70 spring draws the mandrel with nut 13 to the right, thereby exerting a slight camming action on the springs 38 outwardly to maintain a light contact of the scrapers with the interior tube surface. The compression of spring 46 is of just 75

2,018, sufficient strength for the purpose and will yield easily to the movements of the mandrel. When properly adjusted for use with a given size tube, the saddle 24 is on an intermediate position of 5 the portion i2 of the mandrel 6, which allows the mandrel to be still further shifted to the right or to the left, such movements are limited by stop-nut 22 and bumper nut 20. When the mandrel is pulled to the right an increased pressure 10 or expansion results over the initial set pressure or adjustment. This occurs during the withdrawal of the device from the tube. When the mandrel is pushed to the left the decamming of the springs 38 results and thereby releases the 15 tension below the initial set pressure adjustment.

This latter effect takes place when the device is inserted or pushed through the tube when the scrapers meet slight resistance. The object of providing initial light contact with the tube sur20 face is to obtain friction necessary to hold back the scrapers so that positive expansion occurs before withdrawal of the device as a whole.

The bumper nut 20 is formed with a flange and is located so as to close the gap between the inner 25 edges of the scrapers 33 when the mandrel is pulled back or to the right on the pull-out stroke, thereby practically preventing dirt removed by the scraper segments from getting back of the cleaner and being left in the tube. The outer 30 contour of the saddle 24 and the scraper blades are shaped to serve as entering guides for the cleaner to allow easy admittance to the tube.

In the operation of my improved cleaner or scraper, the scraper blades are preliminarily ad35 justed prior to inserting the device in the tube. By turning the mandrel 6 with respect to the scraper blades the expander nut 18 is moved right or left along the threaded portion ί 0 of the mandrel, depending on the direction in which 40 the same is turned. To make the initial adjustment, the mandrel 6 is turned so that the expander nut. 18 moves to the right. The flat springs 38 connecting the scrapers with the saddle 26 are in contact with the grooves of the 45 web portion 42 of the expander nut i8, which prevents the nut from turning with the mandrel. The movement of this nut to the right acts upon the surfaces of the springs 38, which are set at an angle or inclined with respect to 50 the grooves, and cams or forces the scrapers outwardly. This adjustment or any adjustment of the expander nut 18 is maintained by the action of the spring 46 pressing against the coupling 2 and the saddle 26. By the preliminary adjust55 ment the nut 18 is moved just sufficiently to the right so that with the scrapers expanded to the position they will assume in the tube, the nut will engage springs 38, resisting spring 46 to hold the saddle 24 at an intermediate position 60 on the part i2 of the mandrel 6. For any adjustment of the nut 18 obtained by turning the mandrel, the movement of the nut 18 thereafter from left to right and vice versa when the device is pushed in and pulled out of the tube, coincides 65 with the movement of the mandrel, which is limited in its movement relative to the scraper blades to the right by stop nut 22 and to the left by bumper nut 20.

The cleaning device, having been given the pre70 liminary adjustment, is now inserted in the tube, which it enters easily; the spring 46, due to the camming action of the nut 18 on springs 38, pressing the scrapers 33 into light but yielding contact with the inner wall of the tube. If resistance is 75 met by the scrapers as the device moves to the

124 3 left, as by striking a zone carrying scale, dirt or other· adhering matter, the spring 46 will yield, the mandrel 6 moving to the left with the expander nut 18 until the bumper nut 20 fastened on the mandrel stops against the hub or saddle 5 24. It will thus be seen that the decamming of springs 38 plus the endwise thrust of the bumper nut 20 against the saddle 24 will cause contraction of scrapers 33 and push the device, as a whole, through the tube with a very light contact io of the scrapers 33 with the tube. Springs 38 do not tend to prevent this inward movement as nut i8 has moved to the left out of contacting position. This action relieves the springs 38 and also forces the scrapers inwardly, permitting them to 15 yield easily to any resistance met. It will be noted, however, that any loose soot or dirt will be pushed out from the tube in this operation, as the whole action is resisted by the light force exerted by spring 46. 20

On the pull-out stroke of the device to the right, the mandrel 6 is moved to the right relative to the scrapers, as shown in the drawing, carrying the expander nut 18. In this action the bumper nut 20 shifts to the right with the mandrel, closing 25 the gap between the scrapers to prevent the passage of dirt back into the tube, and the stop nut 22 strikes the hub or saddle 24 and takes the substantial strain of the pulling action. At the same time the full tension of the springs 38 is 30 applied to the scrapers by the camming action of the nut 18. It will be evident that the initial adjustment of the scrapers having been made with saddle 24 on an intermediate part of the mandrel 6, since the mandrel is now moved to the right on 35 the pull-out stroke, this movement carries the expander nut 18 to the right from a position of light contact with springs 38 to a position where it greatly increases the pressure of the springs 38 outwardly over that to which they were set in 40 the initial adjustment of the cleaner. This outward pressure acts on the scrapers to force them firmly into scraping contact with the inner wall of the tube. This pressure can be further increased or decreased by turning the mandrel 6 45 while the device is in the tube, to suit desired conditions. It will be noted that in the pull-out operation, the stop 22, bearing against the hub 24, which carries the scrapers 33, places the substantial pull-out strain of the scrapers on the mandrel 50 6 and stop nut. Conversely, when the device is pushed into the tube, the bumper nut 20 contacting against the saddle 24 when substantial resistance is met by the scrapers, takes the strain. It will thus be seen that I have avoided the de- 35 fects of scrapers of the prior art where heretofore attempts have been made to mount the scrapers directly on the springs themselves and in which prior constructions the springs carried both the load and the thrust strains having the disad- 60 vantages that the scrapers tended to get out of true and the springs were put under such a strain that they would not stand up arid were continually breaking or becoming weaker.

One of the manifest advantages of my present 65 device resides in the fact that inasmuch as the scrapers exert a strong scraping force only on the pull-out stroke, I eliminate any tendency of buckling the long rods used for operating the cleaners in long tubes. In other words, by pro- 70 viding the substantial scraping or cleaning operation only on the pull-out stroke as distinguished from the push-in stroke, I minimize the possibility of buckling or bending the rods, due to the operating force longitudinally of the rod and 75

3,018,124 minimize the possibility of the cleaner sticking in the tube.

With my present cleaner, the forward stroke is made easy by the contraction of the scrapers 33 5 through the intermediary of the spring 46, the easy yielding of which allows the mandrel with the nut ί 8 to move relatively to the left, thereby releasing tension of springs 38 on the scrapers, and conversely, on the pull-out stroke when the 10 connecting rods cannot buckle or bend, the scrapers are placed under a direct spring pressure of the leaf springs 38, operating directly through the pulling action; the substantial pulling strain, however, being removed from the springs 38 and 15 carried by the mandrel and stop nut 22. By providing a device which scrapes in a substantial manner only on the pull-out stroke, I am enabled to use either swivel jointed sectional rods or flexible rods to great advantage, the same being re20 quired where full length one-piece rods cannot be used on account of the boiler being located in cramped quarters, leaving no room to operate long single-piece rods. It will be noted with respect to the scraper segments, that they are curved 25 on their outer edges to fit the inside contour of the tubes and that these outer edges are formed with a rake or slant so as to present a sharp edge to the part to be scraped out. In addition, by the provision of the overlap, the scraper faces are en30 abled to pass each other in their shifting movement, and at the same time to maintain a true circular cutting edge presented to the inside surface of the tube.

It is thought that the invention and numerous 35 of its attendant advantages will be understood from the foregoing description and it is obvious that numerous changes may be made in the form, construction, and arrangement of the several parts without departing from the spirit and scope of 40 my invention, or sacrificing any of its attendant advantages.