US2143233A - Apparatus for indicating and recording contours of interior surfaces of tubes - Google Patents

Description

Jan. 10, 1939.

. I F. L. WALLACE 2,143,233 APPARATUS FOR INDICATING AND RECORDING CONTOURS OF INTERIOR SURFACES OF TUBES Filed Dec. 21, 1937 5 Sheets-Sheet l FRANK L..WALLACE INVENTOR ATTORNEY Jan. 10, 1939. F. WALLACE 2,143,233

APPARATUS FUR INDICATIHG AND RECORDING CONTOURS OF INTERIOR SURFACES OF TUBES Filed Dec. 21, 1937 3 Sheets-Sheet 2 O FRANK L. WALLACE INVENTOR BY m 1 13,441 ATTORNEY mdi Patented Jan. 10, 1939 UNITED STATES APPARATUS FOR. INDICATING AND RECORD- ING CONTOURS OF 0F TUBES INTERIOR SURFACES Frank L..Wallace, Port Arthur, Tex, assignor to The Texas Company,

notation of Delaware New York, N. Y., a cor- Application December 21, 1937, Serial No. 180,974

5 Claims.

This invention relates to apparatus for indicating and recording the contour of the interior surfaces of tubes, and concerns particularly an apparatus adapted to indicate and re- 5 produce, in cross section, the exact contour of the interior surfaces of a tube or similar article at a point located at any distance from -the ends thereof. The apparatus of the invention isparticularly useful for determining the contour of H) the interior surfaces of tubes used in tube stills for cracking oil.

As is known in the oil refining art, theoil to be processed is introduced into a series of relatively long tubes suitably joined together to form a tortuous conduit of relatively great length. Throughout a? substantial portion of this conduit the oil is subjected, under considerable pressure, to relatively intense heat from a furnace. Under the working conditions, with the high temperatures on one side of the tube and the pressure of the oil on the other side, together'with the reacting components contained in the oil, the tubes are subjected to what is generally conceded to be relatively severe service. In practice the tubes have a tendency to swell or to be pitted and eaten away at certain, points due to erosion, chemical action or for other reasonsZ. It is of course readily appreciated that the failure, under operating conditions, of a tube with the conse-' quent releasing of the pressure and of the contained' oil into the furnace is a serious matter. Accordingly, all precautions are usually exercised which are possible to avoid such an occurrence and, in this connection, the furnaces are shut down periodically and the tubes examined. Heretofore the inspector has been compelled to confine his observations substantially to those tubes which could be visually inspected from the outside inasmuch as there has been no known instrument available for measuring and recording the contour.of the interior surfaces of the tubes throughout their length. In this connection it is to be pointed out'that the tubes are usually several feet in length, in some instances extending for lengths of from 5 to 30 feet.

While I shall describe the apparatus of the invention in connection with its. use for determining the contour of the interior surfaces of tubes used in tube stills for cracking oil, it will be understood that the apparatus may be used also 'for many other purposes.

In the oil fields the'device can be used for calipering slush pump liners, as a reading can be obtained which can not be obtained by hand calipering with any reasonable expenditure of time.

The device can be used to caliper oil well liner pump barrels to determine whether they should be reworked or not. It can also be used on the plunger barrel to determine what repairs are necessary.

Tubular goods used in drilling, such as kellys, drill collars and drill pipe, can be checked by this device to, determine whether any large amount of fluid cutting has occurred either during regular drilling or during a short blow-out.

The device can be used in internal upset drill pipe, for checking up on the condition of the pipe just below the upset. No satisfactory means for doing this has been available heretofore.

In accordance with the invention the apparatus includes a detecting and transmitting device adapted to be inserted in the tube to be measured and an indicating and recording device which ordinarily is situated outside the tube. The detecting device is adapted to be rotated with in the tube and includes a tracing unit which is adapted to engage and trace the contour of the interior surface of the tube as the detecting device is rotated. It also includes the transmitting motor of a pair of Selsyn motors. The tracing device actuates the shaft of the motor so that the shaft is deflected slightly by any irregularities in the contour of the interior surfaces of the tube.

The recording device includes the receiving or indicating motor of the pair of Selsyn motors. The Selsyn motors operate ontheprinciple of magnetic linkage, a deflection of the rotor of one motor producing an exact deflection in the rotor of the connecting motor both as to degree and direction. Thus, any deflections in the shaft of the transmitting motor are communicated to the shaft ,of the receiving motor, which is correspondingly deflected.- The shaft of the receiving motor actuates a pen arm and any deflections in that shaft arerecorded on a chart by means of the pen arm. The chart is rotated automatically at the same speed as the detecting device is rotated, so that the record on the chart corresponds exactly to the contour of the interior surfaces of the tube being examined.

The invention will be better understood from the following description and the accompanying drawings. Referring to the drawings:

Figure 1 is a view in elevation, partly in sec tion, of apparatus embodying this invention.

Figure 21s a 'view on an enlarged scale of the Figure i is a. view on a still larger scale of the tracing apparatus shown in the lower portion of Figure 3.

Figure 5 is a plan view taken on the line 5-5 of Figure 4.

Figure 6 is a plan view taken on the line 6-6 of Figure 2.

Figure '7 is a tracing of an actual recording.

showing the contour of a heating tube, which tracing was made with apparatus substantially as described herein.

Figure 8 is a chart which may be used as a guide for comparing the contour of the tube examined with that of a tube having the desired dimensions. 1

Referring to Figure 1, the apparatus is shown fully assembled and in position for recording the contour of the interior surfaces of a heating tube. A portion of a heating tube in is'shown, this tube being represented as situated in a heater in which the heating tubes thereof are positioned vertically. A return bend fitting H, which ordi- 1 narily is used for securing the end of the tube ill to a U-bend, rests upon and is supported by a tube sheet i2. The return bend fitting II is provided with an insert or collar l4 in which the end of the tube i0 is secured by upsetting the tube as at I5, and which is tapered as at t6'to engage the tapered portion of a U-bend.

A detecting and transmitting unit indicated enerally as, at l! is shown inserted in the tube by a centering'device 2| which engages the walls' of the tube I 0 and provides a bearing for the pipe H3. The clamping device i9 permits the unit I? and the pipe |8 to be advanced within the tube 8 so that additional examinations may be made.

The arrangement is such that the unit I! may be rotated in the tube In, by rotating the pipe l8 to whichit is secured. A chart holder 22 is connected by-means of gears to the pipe i 8, so that it will be correspondingly rotated upon rota tion of the pipe i8. The detecting unit I! includes a tracing device 23 which is adapted .to trace the contoiu of the interior surfaces of the tube l0 as the unit I! is rotated. The unit I! also includes the transmitting motor 24 of a pair of Selsyn motors and the tracing device 23 actuates the shaft of the motor so that said shaft is deflected or rotated slightly by any irregularities in the contour of the tube Ill. The recording device 28 includes the receiving motor 25 of said pair of Selsyn motors. The stators of the two motors .24 and 25 are connected togetherelectrically and the rotors are energized by an alternating current voltage in a' manner well known to those familiar with self-synchronous motors. Any deflections in the shaft of the transmitting motor 24 are thus communicated to. the shaft of the receiving motor 25 which is deflected in exactly the same way. The shaft of the receiving motor 25 actuates a pen arm 26 and any deflections in the shaft of the motor 25 are recorded by the pen arm on a chart which isheld by the chart holder 22.

Referring to Figures 4 and 5, a bracket 21,

which'is rigidly secured to the-lower end of the transmitting motor 24, supports the tracing device 23. The latter device includes a tracing arm 28 which is secured to the bracket 21 by means of a pin 29, the'pin 29 forming a pivot 1 about which the tracing arm 28 may be rotated.

A spring 38 shown in Figure 4 attached tothe bracket Ti and arm 28 forces the tracing arm outwardly, or upwardly as viewed in Figure 5,

against the walls of the tube l8. arm 28 is shown as generally triangular in shape and the sidethereof opposite the pin 29 is pref- The tracing erably curved and provided with a groove 3|.

A slot 3| 0. is also formedin the arm 28. A guide 32 is rigidly secured to the bracket 21, this guide having a curved side adjacent the tracing arm 28, and being provided with a tongue 33 which engages the groove 3| in the tracing arm 28. The guide 32 thus assists in supporting the tracing arm 28 during rotation thereof. A contact member 34, which is adapted to engage the walls of the tube i0, is secured to one edge or corner of the tracing arm 28. The contactmember 34 is shown as a small plate pivotally mounted on the arm '28 and having two points 3411 and 3417. In case one point becomes worn, the plate can be turned by means of a thumb nut 340 so as to bring the other point into proper position. A gear segment 35 is secured to or formed on the tracing arm 28 on the side of the slot 3|a' opposite the pin 29. The gear segment 35 engages a pinion gear 36 which is secured to the shaft of the transmitting motor 24 and which projects into the slot 3|a.

In operation, the detecting and transmitting unit H, including the transmitting motor 24 andthe tracing device 23, are slowly rotated by hand through 360 degrees in the tube Ill. The point 34a on the tracingarm 28 follows the contour of the interior surfaces of the tube during the rotation of the unit I1. Since the gear segment 35, which is secured to the tracing arm 28, engages the pinion gear 36, the'shaft of the transmitting motor 24 which is secured to-the pinion gear 36 is thereby deflected slightly according to any irregularities in the contour of the tube in.

Referring now to Figure 3, a ring-shaped member or bracket 31 is rigidly secured to the upper side of the transmitting motor 24, this bracket being rigidly secured also to a pipe 38 which is an extension of the pipe l8. The pipe 38 is relatively short and is connected to .the pipe I8 by a pipe coupling 39.

The centering device 2| includes a sleeve 46 which surrounds the pipe 38. The sleeve is threaded at the lower end thereof to receive a collar'and, as shown in the drawings, the collar against a collar 45 which likewise surrounds the sleeve 40 but is longitudinally movable thereon. The collar 45 engages cams 46 which form a part of the fingers 43, therebyforcing said fingers outwardly against the walls of the tube 10. The

fingers 43 are provided with rollers 41 which engage the walls of the tube Ill, these fingers thus serving to maintain the detecting device centered in the tube, the contour of which is to be recorded.

Referring to Figures 2 and 6, the clamping device i9 includes a lower disc-shaped member 48 in which a plurality of radially disposed channels 49 are formed. The channels 49 are adapted to receive clamping dogs 50. The clamping dogs are provided with shoulders 5! which engage the walls of the channels 49 so thatsaid dogs are slidable in said channels, and depending portions 52 which are adapted to engage the upper portion of the return bend fitting II .when

said dogs are expanded outwardly in said chan nels. The clamping device l9 also includes an upper disc-shaped member 53, this member being provided with curved slots 54 adapted to receive pins 55 secured to the clamping dogs 50. Upon rotation of the disc-shaped member 53 the slots 54 expand the dogs 50 outwardly in the channels 49, into engagement with the upper portion of the return bend fitting H. member 53 is provided with a handle 56 which may be used for rotating it.

An upwardly extending nipple 51 is secured to the disc-shaped member, this nipple being threaded at 58 to receive a collar 59. A horizontal extension 60, which is used to support the recording device 20, is secured to the collar 89. A ring-shaped bearing member 6|, which is'used to support the pipe l8 so thatit may b rotated, also is secured tothe collar 59.

A pair of clamping members 62, shown more clearly in Figure 6, which may be quickly fasten'ed around the pipe I! and easily disengaged therefrom, are used to support the pipe It so that said pipe may be advanced into the tube In. The clamping members 62 are pivoted at one side to bolts which secure them to -an annular member 63. The member 63- is adapted to be rotated in the bearing member SI and a hinged bolt 64 is used to fasten the clamping members 62 around the pipe It.

.A gear 65 is secured to or formed on the.

annular member '3. The gear '65 is used, together with a second gear 66 which is secured to the chart holder 22, to rotate said chart holder when the pipe II. is rotated. The chart holder 22 and the gear, 86 are secured to opposite ends of a sleeve '1, this sleeve 61 surrounding and adapted to be rotated upon a vertical pin 68. The pin 8 is secured to the horizontal extension SI and has a shoulder which provides a bearing for the lower end of the sleeve 61. The pin 64 is threaded to receive a nut 69 which secures the sleeve 61 against removal from said pin.

A bracket 10 which is in the form of an inverted U and which straddles the chart holder 22 is supported upon extension 64 and in turn supports the recording unit 20. The recording unit II is in many respects similar to the detecting and transmitting unit l1, above described. The receiving motor 25 is supported directly upon the bracket I. and is connected to the transmitting motor 24- by a flexible cable ll which passes through the pipe ii. .A branch H a of the cable H may be connected to a suitable source of alternating current to energize the rotor windings of the motors 24 and 25. The receiving motor 25 is, provided at the lower end thereof with a pinion gear (not shown) which is similar to the pinion gear 38 of the detecting unit. The pinion gear engages a gear segment which is tion.

The disc-shaped similar to the gear segment 35 of the detecting unit, thereby actuating a member I2- which corresponds to the tracing arm 28 of the detecting and transmitting device. The member 12 is rigidly secured to a pin 13, and travels in a guide The pin 13 extends downwardly through a bearing 15 which is formed in the bracket 10 and is rigidly secured at its lower end to the pen arm It.

It is believed that the operation of the apparatus will be clear from the foregoing descrip- However, in summarizing, the detecting 14, the guide being secured to the bracket 10.

and transmitting unit I1 is placed in the-tube, Y

the inner contour of which is to be recorded, and the clamping device I9 is adjusted so that the tracing arm '28 will be at the proper distance from the end of the tube. A blank chart such as is shown at 16 in Figure 7 is secured to the chart holder 22 and the pen arm 26 adjusted to make contact with the chart. The unit I! is then rotated slowly by turning the pipe I! through 360 degrees. The tracer point 34a will follow the interior surface of the tube and through the arm 28 and the gearing 35 and 36 will cause the rotor of the motor 24 to be defiected or rotated slightly in accordance with any irregularities in the contour of the tube surface being examined. Due to the magnetic linkage between the motors 24 and 25, the pen arm will move on the chart at the same time and to the same extent as the tracer arm 28 is moved. Becauseof the gearing connection 65 and 66 the chart holder 22 will revolve simultaneously with the detecting unit and the tracing 11 of the pen on the chart will therefore coincide exactly with the interior surface of the tube being examined.

Figure 7 represents an actual tracing showing the cross-section of a tube which has undergone spotty corrosion. The chart 16 on which the section of the tube calipered is recorded may be made of transparent paper, thus making it possible to superimpose the contour 11 of the tube on the master chart for that particular size tube such as is shown in Figure 8, thus by comparison the extent of pitting or corrosion of the interior tube surface will be clearly indicated.

As has been stated hereinbefore, it is to be understood that this apparatus is not limited to use in examining the interior surfaces of still tubes. The interiors of various kinds of holes may be readily studied in a similar manner since it is merely necessary to clamp the shaft supporting the detecting and transmitting unit in proper positon within the hole to be examined.

Obviously many modifications and variations of the invention may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated by the appended claims.

I claim:

1. An apparatus for indicating the'contour of the interior surface of a tube, comprising 'a detecting unit adapted to be positioned and rotated within the tube, said detecting unit including one of 'a pair of electrical self-synchronous motors, a tracer arm connected to the rotor shaft of said motor and adapted to engage and follow the interior surface of said tube as the motor is rotated in the tube, an indicating unit including the second of a pair of self-synchronous motors, said second motor being rigidly mounted exteriorly of said tube, and 'an indicating arm secured to the rotor of said second motor, saidpair of motors 1g being electrically interconnected so that as said detecting device is rotated within the tube, deflection of said tracer arm will produce corresponding deflections of said indicating arm.

2. An apparatus for indicating the contour of the interior surface of a tube, comprising a detecting unit adapted to be positioned and rotated within the tube, said detecting unit including one of a pair. of electrical' self-synchronous motors, atracer arm connected to the rotor shaft of said motor and adapted to contact with and follow the interior surface of said tube as the motor is rotated-in the tube, an indicating unit including .the second of the pair ofself -synchrono us motors,'said second motor being rigidly mounted exteriorly of said tube, a chart holder having a chart aflixed thereto, gearing between said chart holder and said detecting unit for rotating said chart holder in synchronism with the rotation of said detecting unit, a pen arm secured to the rotor of said second motor and in contact with said chart, said pair of motors being electrically interconnected so that as said detecting device is rotated within the tube, deflection of said. tracer arm will produce corresponding deflections of said pen arm so as to trace on said chart the interior contour of said tube.

3. An apparatus for indicating the contour of the interior surface of a tube, comprising a detecting and transmitting unit adapted to be positioned and rotated within the tube, said detecting and transmitting unit comprising one of a pair of electrical self-synchronousmotors, a pipe member secured to said motor and adapted to support said ,motor in operative position within the tube, means for clamping said pipe member to said tube so that the-pipe and motor may be rotated with respect tosaid tube, means cooperating with said clampingmeans for maintaining said pipe and motor concentric with respect to said tube, a tracer arm connected tothe rotor shaft of said motor and adapted to engage'and follow the interior surface of said tube as the motor is rotated in thetube, an indicating unit including the second of a pair of self-synchronous motors-and an indicating arm secured to'the rotor of said second motor, said pair of motors being electrically interconnected so that as said detect; ing and transmitting device is rotated within the tube, deflection of said tracer arm will produce corresponding deflections of said indicating arm.

4. An apparatus for indicating the contour of the interior surface of a tube comprising a pair of electrical self-synchronous motors, electrical connections between said motors so that as the rotor of one motor is rotated, the rotor of the other motor will be correspondingly rotated, a tracer arm secured to the rotor of the first motor and an indicating arm secured to the rotor of the second motor, means for supporting said first motor within and concentrically of the tube with said tracer arm engaging the interior surface of the tube, and means for rotating said-first motor within the tube while said tracer arm follows the interior contour of the tube, the arrangement being such that as said first motor isrotated movements of said tracer arm caused by irregularities of the interior surface of the tube will cause deflections of the rotor of said first motor and said rotor deflections will cause corresponding deflections of the rotor and indicating arm of the second motor.

5. An apparatus for indicating the contour of the interior surface of a tube comprising a pair of electrical self-synchronous motors, electrical connections between said motors so that as the rotor of one motor is rotated, the rotor of the other motor will be correspondingly rotated, a tracer arm secured 'to the rotor of the first motor and an indicating arm secured to the rotor of the second motor, means for supporting said first motor within and concentrically of the tube with said tracer arm engaging the interior surface of the tube, and means for rotating-said first motor within the tube while said tracer arm follows the,

interior contour of the tube, means for rigidly supporting said second motor exteriorly of said tube, a marking device secured to said indicating arm, a chart holder having a chart aflixed thereto and adapted to be contacted by said marking device, gearing between said chart holder and the supporting means for the first motor so that said chart holder and chart will be rotated in synchronism with said first motor whereby movements of said tracer arm caused by irregularities in the inner surface of said tube will be transmitted to the indicating arm of said second motor to cause said marking device to trace on said chart the interior contour of said tube.

FRANK L. WALLACE.

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