US2283522A - Abrasive device for cleaning still tubes and the like - Google Patents

Description

May 19, 1942. H. G. WEINLAND 2,283,522

7 ABRASIVE DEVICE FOR CLEANINGSTILL TUBES AND THE LIKE Filed April l6, 1941 m $53M J" m a a ,7 W m H vi h! lir I w \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\M\\\\\\\\\\\\\\\\\\ 5 N ow PatenteiMey 19, 1942 2,283,522 ABRASIVIFIDEVICE FOR CLEANING STEAL Application April 16, 1941, Serial No. assets,

8 Claims.

The invention relates to a tube cleaner designed for removing encrustations from the interior of tubes or boilers, stills, or the like.

One object of the invention is to provide a self-feeding tube cleaner of increased efliciency. Another object of the invention is to combine an automatic feed with an abrasive tube cleaner.

Another object of the invention is to provide a tube cleaner feeding device which shall not score the tube. Another object of the invention is to provide a rapid feeding eflicient tube cleaner producing a smooth and polished surface upon the tube. Another object of the invention is to im- The air motor and the cutters would be introduced into the tube to be cleaned. With the use of such tools .various difliculties have been encountered, especially the injury of the still tube by the steel cutters, especially when the operator left the cutters in action in one particular place. Furthermore, it has been found necessary frequently to renew or sharpen the steel cutters.

Referring now to the drawing and first to Figure 1, a still tube to be'cleaned of encrustation is indicated at I0, the encrustation of hard car bon or similar material being indicated at H. The tool of my invention may be mounted on the end of a suitable air turbine l2 which is energized by compressed air passing through a rubber hose l3. Such -air turbines l2 mounted on the end of the hoses l3 are nowreadily available and will not, therefore. be particularly de- In the accompanying drawing illustrating one of many possible embodiments of the mechanical features of this invention,

Figure 1 is an axial sectional view of a still tube showing the tube cleaner of the invention located therein, illustrated in elevation;

Figure 2 is an axial sectional view of the tube cleaner head, showing the parts on an enlarged scale;

Figure 3 is an axial sectional view of the tube cleaner head, showing the parts on the same scale as Figure l, the plane of the section being 90 degrees angularly removed from the plane of the section of Figure 2; and

Figure 4 is a front elevation of the tube cleaner head, the parts being shown on the same scale as Figure 2.

As conducive to a clearer understanding of the present invention, it is noted that in the operation of stills for cracking petroleum and for iractionating the higher hydrocarbons, the still tubes become encrusted with a carbonaceous deposit which is often very hard. Such encrustation not only decreases the capacity of the tube but also materially decreases its thermoconductivity and, therefore, it has been customary to clean out the encrustation from these tubes. For this purpose there have been provided air motors mounted on the ends of heavy hoses and driving divers forms of steel cutters.

scribed, and any other prime or secondary mover may be provided within the scope of the present invention. Such air turbines are capable of revolving a cleaning tool at speeds of the order of 1000 to 3500'R. P. M.

Still referring to Figure 1, at the end of the turbine, opposite the hose I3 is the driven spindle Hi. This, as is customary, is drilled and tapped and fitted to a threaded clevis stud |5 which is connected to another threaded clevis stud l6 by means of a link |l, these three parts constituting a. universal joint.

Referring now to Figures 1, 2 and 3, I provide a nut 20 having a threaded bore 2| of small diameter and a threaded bore 22 of larger'diameter. The threaded clevis stud l6 fits in the bore 2|. I further provide a head comprising mating parts 23 and 24 having semi-cylindrical threaded portions 25 and 26' which together fitin the larger threaded bore 22 of the nut 20. The mating parts 23 and 24 are removably held together by three pins 21 fitting into appropriate holes 28' as shown. When the nut 20 is screwed onto the pair of semi-cylindrical portions 25 and 26, the mating parts 23 and 24 are locked together and form a rigid head for the mounting of the abrasive sticks to be described.

As shown in Figures 2 and 4, the head 24 is a cylinder with a portion thereof cut out by parallel chord planes,thus leaving projecting ends 30 and 3| which together form a fork. I provide a pair of parallel holes 32 and 33 in the projecting ends 30 and 3|, the hole 32 in the end 30 being opposite the hole 32 in the end 3|, and the hole 33 in the end 30 being opposite the hole 33 in the end 3|. These holes or bores 32 and 33 pins 35, see especially Figure 3. The trunnion pins 35 are inserted into theholes 3 2 and 33 as the mating parts 23 and 24 are assembled. The trunnion pins 35 may be made of steel, as preferably is thehead 23, 24 and the nut -20, and the trunnion pins 35 are embedded in and project from a pair of abrasive sticks 40. One end of each abrasive stick 40 is preferably rounded over as shown at 38 and a shaped rubber insert 39 is provided which has the effect of cushioning vibrations. I

For the manufacture of the sticks 40, I may proceed as follows: Taking a quantity of silicon carbide abrasive in coarse grit size, for example to 16 mesh grit size, and placing it in a mixing pan, I add furfural and mix until each granule is coated with furfural. I mix together a quantity of A stage phenol formaldehyde, abrasive fines and quick lime. I add this mixture to the mixing pan while continuing the mixing. I then add a quantity of neutral creosote oil and continue the mixing until the creosote oil has been thoroughly distributed throughout the mass of ingredients in the pan.

The A stage phenol formaldehye is preferably permanently fusible solid phenol formaldehyde resin with sufficient hexamethylene tetra-, mine to harden it. .The abrasive fines may be very fine particles of any suitable abrasive, for example silicon carbide or aluminum oxide in grit sizes of theorder of 400 to 600' mesh grit sizes. As a specific example of proportions for a suitable stick, I may make up an abrasive structure as follows:

Per cent by volume Abrasive 58 Bond 34 Pores 8 In the foregoing the bond comprises A constitute journals for the reception of trunnion .may be located as shown. I have found that a pair of. hairpin shaped wires 46 for each stick is satisfactory. Preferably these pass around the trunnions and at least one end of each wire extends close to the outer surface of the stick which is adjacent the tube I0 when the stick is being used.

So far as already described, the parts and features of the tube cleaner are the same as described in my prior copending application Serial No. 321,951; However, the nut 2!] hereof has a different shape and according to the present invention I provide self-feeding means to feed the tool and the turbine l2 along the still tube It. According to the present invention this self-feeding means may take the form of circular racks 50 loosely mounted on pins 5| andwhich are somewhat loosely mounted in bores 52 and 53 in the nut 20, which bores are separated by recesses 54 provided in the nut 20 to receivethe circular racks 50. The bore 53 is slotted in a radial-direction to permit radial adjustment of the racks50 to slight variations in the diameter of the tube Ill. The axes 'of the pins 5| are inclined to the axis of the tool. so that a feeding movement is given thereto by the gripping of the wall of the still tube III by the teeth 56 of the circular racks 50. Preferably I provide a plustage solid resin 50% by weight, alumina fines 40% by weight and quicklime, CaO, 10% by weight. I may use 65 cubic centimeters of fur-' fural and 25 cubic centimeters of creosote oil per pound of the above bond.

The foregoing is given as an illustrativeexample only but it is noted thatthere is thereby formed a hard.abrasive structure of slight po- So far as the particular bondingv ingredients are concerned and the proportions thereof, I may vary the foregoing widely and, infact, other bonds besides phenol formaldehyde may be used, such as rubber, shellac and the like. But I have found that of the common abrasives now known, only silicon carbide is satisfactory and I also find that the abrasive structure should be hard and dense.

I provide suitable molding equipment to form sticks of the general shape shown in Figures 1 to 4 inclusive which may be in general described as rectangular parallelopipecls. Preferably the outer or cutting side of the sticksis formed to provide initially a raised portion 4| joined to two the trunnion pins 35 into the sticks 40 at one rality ofracks 50, for example, three as shown. By making the racks loose on the pins and the pins loose in the holes, wear is reduced, there being two points of rotation. I provide a large washer 58 locked in place by the clevice stud Hi to limit the pins axially in one direction. For removal of the pins 5|, holes 60 extending from the outside of the nuts 22 and in front of the As shown in Figure 1, the holes 52 are slightly 20 to the'threaded bore pins 5| may be provided.

offset from the holes 60, so the pins 5! cannot move axially in the other direction.

Referring now to Figure 1, a particular circular rack 50 is shown in elevation. It has an inclination of a few degrees to the axis of the tool, as will be readily. seen. The circular rack 50 may be said to be skewed to the axis of the tool. The skew of each circular rack 50 to the main axis of the tool is the same. The racks are skewed in the same angular direction. The tool of the invention rotates counterclockwise in Figure 4, so in Figure 1 the circular rack 50 is moving downwardly. Its teeth 56 cometo a broad point, so it frictionally grips the steel of thetube l0, and because the point is broad there is no cutting action. The abrasive sticks 40 clean out the still tube and polish it, leaving a smooth surface therein which is' so important in the oil cracking industry, While owing to the use of a circular rack, the propelling device feeds the tool along the still tube without scoring the tube and the maximum gripping and propelling effect is obtained with the minimum of result upon the tube itself.

Considering now the operation of'the device,

Q the air turbine I2 is introduced into the tube I0 end thereof, a shown, preferably providing metal washers 45 to locate the trunnions 35 and to transfer the thrust to a wide area of. contact.

by means of the hose l3 in the usual way and the air is turned on. Sticks 40 cut the encrustation H and as the sticks wear away they move apart under the influence of centrifugal force. The sticks 40 are always pressing against the encrustations by reason of the centrifugal force,

thus providing a satisfactory abrading pressure and at the same time causing the encrustation H to be evenly removed. That is to say, by reason of the fact thatthe sticks tend to swing apart on their trunnion pins 35, they press against the encrustation H at all angular posi tions irrespective of whether the tool is in exact axial alignment with the tube ID or not.

Whereas it may take from fifteen minutes to four hours to cut out hard encrustations with the metal cutters, abrasive sticks according to my invention rarely require more than fifteen minutes to do the job, and sometimes will clean a tube in three or four minutes. In this particular work time is of great importance since the entire unit is shut down while the tubes are being cleaned.

I have found that the combination of the use of silicon carbide and the embedded wires 46 gives an abrasive which will cut the encrustation I 1 without detrimentally cutting the tube H). The exact reason forthis I do not know, especially since theoretically the wires 46 should wear away faster than the abrasive and also silicon carbide should abrade the steel of the tube.

Nevertheless the results have been observed in actual practice and confirmed by repeated tests. Within the scope of they present invention, other abrasive shapes may be used.

It will thus be seen that there has been provided'by this invention an article and a method in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A tool for removing encrustations in still tubes and the like comprising a head adapted to be rotated about an axis, an abrasive stick mounted on said head, and a tube gripping member mounted for rotation on an axis skewed with skew feeds the parts in the still tube.

3. A tool for removing encrustations in a still tube or the like comprising a rotatable member, a plurality of rotatable members having tube gripping peripheries mounted forrotation with respect to said rotatable member on axes skewed nected to the rotatable member to be rotated and fed by it in the tube.

4. A tool for removing encrustations in a still tube or the.like comprising an abrasive stick,

means mounting the abrasive stick for rotation, and a member mounted on'said means for rotation about an axis skewed with respect to the axis of rotation of the means and provided with a tube gripping periphery, whereby to feed the abrasive stick as it rotates in the tube,

5. A tool for removing encrustations in a still tube or the like comprising a first rotatable member, a plurality of rotatable members formed as circular racks whose peripheries are thus adapted to grip the inner wall of a tube without marring the wall-of the tube, said members being mounted for rotation with respect to said first rotatable member on axes skewed with respect to the axis of rotation of the first rotatable member, which axes are at equal distances from the axis of the first rotatable member in the still tube as it rotates, and an abrasive stick connected to the rotatable member to be rotated and fed by it in the tube.

6. A tool for removing encrustations in a still tube or the like comprisinga first rotatable member, a plurality of rotatable members having tube gripping peripheries mounted .i'or rotation with respect to said first rotatable member on axes skewed with respectto the axis of rotation of the first rotatable member, which axes are at equal distances from the axis of the first rotatable member, whereby to feed the first rotatable member in the still tube as it rotates, and a pair of tube or the like comprising an abrasive stick,

means mounting the abrasive stick for rotation, and a member formed as a circular rack mounted for rotation on said means about an axis 1 skewed with respect to the axis of rotation of the means whereby to feed the abrasive stick as it rotates in the tube without marring the tube.

8. A tool for removing encrustations in a still tube or the like comprising a pair of abrasive sticks mounted on parallel axes transverse to the axis thereof as a unit, means mounting the abrasive sticks for rotation about said axis whereb as the pair of sticks as a unit rotate about the said axis of the said means they will swing farther apart on their parallel axes and centrifugal force will press them against the encrustation, and a member mounted on said means I: unting the sticks, said member being mounted for rotation about an axis skewed with respect to the axis of the said means, and said member being provided with a tube gripping periphery, whereby to feed the pair of abrasive sticks as they rotate-in the tube.

HERMON G. WEINLAND.

Images