US1872410A - Method of controlling scale in gas cutting of metals - Google Patents

Description

Patented Aug. 16, i932 I N PATENT orrlcr. j

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My invention relates to the art of as cutting metals which-is extensively em oyed in 11580; I0. 4,493. from the pores of the scale, thereby I the scale to disintegrate and fly of from the the cuttingof slots in ferrousmeta s and re-\ surface of the sup orting metal in the form lates particularlyl to a method and apparatus for preventing t e presence of scale from interfering with'the cutting operation.

The present utility of my invention is in cutting of slots in pipe or seamless tubing for the purpose of making strainers or screen for wellsftherefore, in order to simplify, the

disclosure'of my invention without limiting the scope thereof, I'shall hereinafter describe the invention relative to the gas cutting bf slots in ferrous metal pipes and tubes, it being understood that t e precepts, of the in-. vention maybe ap lied to the cutting of slots in various metal p a'tes and bodies.

It is found that the presence of oxides or scale on the surface of metal will interfere with the action of a {ct of-cutting gas which. in practice is enera lyoxygen. This inter-- ference with t e cuttingaction is especially important in the cutting of slots in pipefor the purpose of making a well screen or strain-. er and in the previous practice it has been customary to remove the oxides or scale from the surface of the pipeso as to leave the area adjacent to the line along which the cut is to be made absolutely clean inorder to prevent interference with the cuttingv of the slots due to the presence of scale. I j, g

My present invention [comprehends a method whereby the'cutting operation may be conducted in the presence of 'scaletherefore eliminating the necessity of removing the scale from the pipe, and accordingly re- Thereare a numbero ting of metals due'to the resence of" scale, among which are the containing of moisture in the scale either in the form of hydrated oxide or water mechanicallyheld in the pores of the scale, and the difference in expansion and contraction of thescale and the metal on which such scale is formed.

Naturally, the high heat produced by the cutting torch or tip causes volatili'z'ation of the moisture .content-Iof the scale more rapidly than such a volatilized moisture can escape of flakes. Theseakes are often thrown diuncover the flame and gas openings thereof before the torch cani g ln be used. In addition to the presence of moisture .in thescale, therapid application of heat is found to cause disintegration of thescale and the breaking off of scale particles from the supporting body of metal.

Anobject of myinvention is to method. and apparatus for control fi f iit in thepresence of a gas cutting operation by heating thescale i'n'the zone surrounding the line along which-a cut is to be conducted for the purpose of c h rgitionin the scale to avoid the disintegratio thereo and the cor- :responding unsatisfactory results, when the cutting torch is applied for. the pu of making a cut in the supporting meta The principal utility of this prelimina heatingoperation is to drive from the sc Q content the moisture, which may be h dratcd oxide or moisture mechanically carri by the scale. 1 r

Further objects and vention will be made evident throughout the following part of the specification; Referring to the drawing which is for illustrative purposes only, 1 Fig. 1 isa vertically sectioned fragmentary view of diagrammatic character showing an apparatus suitable for practice of my present invention. 5

Fig.2 is a view showing a surface ,of a metal I body, such as a pi e, which has been gas cut inthe presence 0 surface scaleand in accordance with my present invention, l Fi 3 isja vertically sectioned view to Fig; 1 but to reduced scale, showing alternative form of apparatus by which the invention may be practiced. v i

advantages of the im- 8 6 mixed with oxygen, or may-be common gydrtf 1 g.

t op tion f penetrating 9 wall 16,10; as .to heat the'metal Fig. 4 is an enlarged fragmentary partly sectioned view showing the-conditions en countered in the making of a cut in a metal body having a coating oxide, or scale thereon. 1 In Fig. 1, I show a pipe 11; extending throughan opening 12 in a support 18 which carries 'a preliminary heatingv torch 14,. a'

drill motor and a cutting torch 16.

accordance with the art of slottinIg pipe disclosed in my United States Letters atent No. 1,666,166, granted April 17, 1928, the mechanism shown in Fig. 1 is capable of first drilling small holes in the ipe, after-which as a rotatable head 21, carrying 'a lural:

ity of tips 22 so that in event one of t e tips, 22 should fail to roperly functionthe head so 21fmay be rotated to bring another tip into working position. The preliminary heating torch is equipped with a tip 23 from which a flame 24 issues. The fuel employed to produce the flame 24 may be acetylene properly carbon ,gas intermixed with airi'In I however I have shown flexible conduits 26 and 26sleading intmth'e torch 14 through ractice receives acetylene gas and oxy-' t irough flexible conductors or tubes simto thoseshown at and 26. r "In Fig. 1 he drill 19 is shown during the "pipe 11 and in of the torch 16 a been previously cut-is shown.

the cutting equipment the strncture 18 is operation of the drilling mechanism and the cutting torch'16. During the drilling opera tionthe heatingflamee issue from the torch. rrounding the hole 81 and when the drill sp die 17 is raised a cu ting jet of oxygen is directedthrough the hole leftward direction'causing the jet which is 22 ofthe'torch .16 to cut; ,Ifiaalotinthew wofthepi'pelh During sues fromthe P ta; '4 i th I of 'co:1dn(l:ltmg e roper gaseoussu ces' te torch. Th

heat; p e cutting torch, in accordance with accordance with the. convenient use of a aavaaio the heating of the area aurrounding the bis.

81 by flames issuing from the cutting tore tip 22, the flame QA may issue from the torch 14 1 so as to play on the surface of the pipe 11 a or rather on the scale or oxide coating'of the pipe. The flame 24 is continued throughout the time of the travel of the su port 18 in leftward direction so that an e on ated area on the pipe is heated, this hea being so'positioned that the next hole formed by operation of the drill 19 will be situated at the rightward end thereof, as indicated at 36ofFig.2.

After the hole has-been drilled at 36 there in the heated area 35 is relatively moved into position of cooperation with.) the cutting torch 16 sothat when the cuttfng torch is a ain ofierated'a slot 32 will be cut centrally a ong t e heated area which then'occupies the relative position indicated at 37 in Fig. 2.

From the foregoing it will be perceived that before the cutting torch 16 is operated to cut a slot in. the pipe 11 a zone is heated surrounding the line along which the cut is to v be made, the heating of this zone being eflectiveto greatly reduce or to 'entirelly'prevent disintegration of the oxide or sca o coati the, pi during the operation of the cut t ng torc 16, thereby avoiding the-diflicul- I ties heretofore encountered in the cuttin' of scale thereon and which cu ties ms 40 in which a slot 41 1s being'cut by a gas jet in' addition to the jet 42 provides heating flames 44. The pipe 40 .is shown with its customlagg' coating. of oxide or'.sc ale 45. The need by the he'ating'flames 44 and by the cutting action'of the jet 42 causes flakes, 4 to break, curl up, or fly oil from the oxide coating or scale'45 on the pi 40; As indicated by dotted lines 48 in ig. 4 a'flake of ,scale is often carried against the lower end h h thitO of the a ent wit eti 22- dn ll l i oleis shown. Tgthe right of the drill hole 31, a slot32 which has of thetorch 48 with the result of either causing the torch to back-fire or'shutting ofl.

- the proper issue of the heating'flames, or the cutting jet. v

y M invention assimilate-11m such con itions as those justdescribed by 'condishow aportion of the pipe wall A j necessary the cleaning ofthe I which results in dehydrati'n the scale and also producing in the zone 0 the line of-cut:

disintegration or flaking of-theiscale either as a the result ofvolatilization of moisture there- 81, whereupon the head 13 is movedin reto. Thisconditioning or preliminary heating of the scale is accomplished before the zone of the line of cut is operated on by the flames and gas issuing from the cutting torch,

In the preferred practice of the invention the scale and the pipe adjacent thereto are heated to a temperature of from 250 F. to 350 R, which is above the boiling point of water, such temperature accomplishing the desired effect of dehydrating the scale, con- .ditioning same for the cutting operation.

In Fig. 3 I show an alternative form in which the invention may be practiced, including a frame 60 relatively movable to a pipe 61, a drilling mechanism 62, and a torch 63 mounted thereon. Into the forward end 64 of the pipe 61 a burner head 65 is projected on the end of a pipe 66 through which gas or a fuel mixture is conducted to the burner head 65. The burner head is at all times maintained in a position aheadof the torch 63 and its flames 6? are directed radially outwardl against the wall 68 of the pipe 61 so as to eat the pipe and likewise the scale or oxide coating carried thereon preliminary to the cutting operation to be accomplished by the cutting torch 63.

During the operation of the device shown in Fig. 3 a circulation of air is maintained in leftward direction through the pipe 61 by a suitable exhaust fan located at the left end thereof, the air entering the pipe through the last few rows of slots 69 which have been reviously cut, as indicated by arrows 70 and Sowing leftwardly through the pipe 61 and around the burner head 65 as indicated by arrows 71.

The mechanism disclosed in Fig. 1 beats only limited areas or zones of the scale and pipe surrounding the line of cut to be folowed by the cutting torch and the form of mechanism shown in Fig. 3 heats the entire wall of the pipe, this latter practice requiring a larger amount of heating but in a measure compensating therefor by the use of a very cheap fuel in the burner head 65.

Although I have shown a simple and practical embodiment of my invention it is recognized that some of the elements thereof may be replaced by other elements capable of performing the same functions in a. substantially equivalent manner; therefore the invention is not to be limited by the details of the foregoing disclosure but should be accorded the full scope of the following claims.

I claim as my invention:

1. A method of controlling scale in gas cutting of metals having scale thereon, com-- heating the scale in the zone of the prising cut to e made to a temperature between 250 F. and 350 F. preliminary to application of the cutting torch to make such cut and at a' time sufiiciently ahead of said cut to permit complete conditioning of said scale against disruptive action of the scale in ofthe cutting plane.

the presence 2. A method of controllin scale in gas cutting of metals havin scale t ereon, com rising the application 0 an initial heating ame 1 in a manner to heat the scale in the zone of the cut to be made to a temperature between 250 F. and 350 F. preliminary to application of the cutting torch to make such cut and at a time sufliciently ahead of said cut to permit complete conditioning of said scale against disruptive action 0 the scale in the presence of the cutting flame.

3. A method of the character described for cutting a slot in a metal wall, including: heating the metal in the zone of the slot to a. temperature between 250 and 350 F.; drilling a starting hole in said wall in said heated zone; and, by use of a jet of cutting gas,- cutting a slot startin at said hole and extending within said heate zone.

4. A method of'the character described for 7 cutting a slot in a metal wall, including:

heating the metal wall to a temperature between 250 and 350 F.; drilling a startin hole in said metal wall; heating the meta surrounding said hole to a temperature for producing combustion of the metal in the presence of a cutting gas; and, by the use of a jet ofcutting gas, cutting a slot in said wall starting at said hole.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 10th day of April, 1930.

' CLARENCE J. COBERLY.

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