CA1069418A - Method and apparatus for flame hardening the inner wall surface of tube bends - Google Patents
Method and apparatus for flame hardening the inner wall surface of tube bendsInfo
- Publication number
- CA1069418A CA1069418A CA235,228A CA235228A CA1069418A CA 1069418 A CA1069418 A CA 1069418A CA 235228 A CA235228 A CA 235228A CA 1069418 A CA1069418 A CA 1069418A
- Authority
- CA
- Canada
- Prior art keywords
- tube bend
- burner
- tube
- flame hardening
- hardening
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000001816 cooling Methods 0.000 claims abstract description 36
- 230000033001 locomotion Effects 0.000 claims abstract description 19
- 239000000498 cooling water Substances 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims description 11
- 125000006850 spacer group Chemical group 0.000 claims description 8
- 239000007769 metal material Substances 0.000 claims description 2
- 235000019628 coolness Nutrition 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 11
- 238000010791 quenching Methods 0.000 abstract description 5
- 230000000171 quenching effect Effects 0.000 abstract description 5
- 230000005484 gravity Effects 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 244000085918 Eucalyptus exserta Species 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
- C21D9/085—Cooling or quenching
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Method and apparatus for flame hardening the inner wall surface of tube bends of a circular configuration wherein either a flame hardening burner is passed longitudinally through the internal cavity of a tube bend which is mounted in a fixed position, or alternatively the tube bend is moved over a stationary flame hardening burner. This relative movement between tube bend and burner is effected along a circular path corresponding to the longitudinal center line of the tube bend. Subsequently to flame hardening the heated inner wall surface of the tube bend is quenched with cooling water discharged from water sprinklers disposed downstream of the flame hardening zone.
During flame hardening and quenching the tube bend is continuously maintained in positions such that the quench-ing water may leave the tube bend by gravity. The apparatus includes mounting means for the tube bend, the flame hardening burner and the associated cooling means and allows relative movement between the tube bend on the one hand and the burner and cooling means by means of a drive assembly.
During flame hardening and quenching the tube bend is continuously maintained in positions such that the quench-ing water may leave the tube bend by gravity. The apparatus includes mounting means for the tube bend, the flame hardening burner and the associated cooling means and allows relative movement between the tube bend on the one hand and the burner and cooling means by means of a drive assembly.
Description
The present inventlon relates to method and apparatus for continuously surface hardening the inner surface of tube bends of a constant radius of curvature by means of flame hardening, with or without modifying the core properties of the material.
In the well-known method of flame hardening the layers adjacent the surface of a metallic workpiece are locally heated up to hardening temperature by means of gas and oxygen burners, without thereby modifying the core properties of the material.
This method is employed for the surface hardening of shafts, rollers, drums, sleeves, teeth surfaces and the like as well as for the surface hardening of the inner surfaces of straight tubes or pipes It is also known to harden tube bends. When the hardening of tube bends is re~uired, the tube bends are heated ~ -up to hardening temperature in a hardening or tempering furnace and subsequently quenched in a water bath or an oil bath. A
major drawback of this method of hardening is that the obtained hardness is not equal throughout the workpiece. This irregular-ity is caused by the formation of bubbles within the tube bends and by nonuniform quenching. Further disadvantages of this method are a relatively high percentage of rejects and high costs associated with the furnace hardening operation. As far as Applicant is aware, it has never been tried to surface harden tube bends b~ flame hardening.
It is therefore an object of the present invention to provide novel and improved method and apparatus for the surface hardening of the inner surface of tube bends.
It is another object of the invention to provide ~
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In the well-known method of flame hardening the layers adjacent the surface of a metallic workpiece are locally heated up to hardening temperature by means of gas and oxygen burners, without thereby modifying the core properties of the material.
This method is employed for the surface hardening of shafts, rollers, drums, sleeves, teeth surfaces and the like as well as for the surface hardening of the inner surfaces of straight tubes or pipes It is also known to harden tube bends. When the hardening of tube bends is re~uired, the tube bends are heated ~ -up to hardening temperature in a hardening or tempering furnace and subsequently quenched in a water bath or an oil bath. A
major drawback of this method of hardening is that the obtained hardness is not equal throughout the workpiece. This irregular-ity is caused by the formation of bubbles within the tube bends and by nonuniform quenching. Further disadvantages of this method are a relatively high percentage of rejects and high costs associated with the furnace hardening operation. As far as Applicant is aware, it has never been tried to surface harden tube bends b~ flame hardening.
It is therefore an object of the present invention to provide novel and improved method and apparatus for the surface hardening of the inner surface of tube bends.
It is another object of the invention to provide ~
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.. . :: . .. . ~ -me-thod and appara-tus o~ the above type which are hiyhly economical.
It is a further object of the invention to provide ~ -method and apparatus of the above type allowing to selectively harden the outer circumferential region of tube bends since this outer region is subject to the heaviest wear during service of the tube bends. By selective hardening in this manner -the tube bends retain a certain degree of elasticity in the region of their inner radius or circumerence so that harden.ing strainsmay be compensated. ~ .
The present invention now proposes a metho~ of continu- ~ .
ously surface hardening the inner surface of tube bends of a constant radius of curvature by means of flame harden.ing wherein : : :
the tube bend is moved along a circular path of a radius corres- - ~.
ponding substantially to the radius of curvature of the tube .
bend center line over stationary flame hardening means so that the stationary flame hardening means will be disposed within the inner cavity of the tube bend and the flames of the hardening means impinge on the inner tubular wall of the tube bend.
Thereby the tube bend may be moved from an uppermost initial position through a flame hardening zone located in a laterally displaced position which is lower than the uppermost initial position of the tube bend movement. ..
The invention furthermore proposes a method of continu- .
ously surface hardening the:inner surface of tube bends of a constant radius of curvature by means of flame hardening, with or without modifying the core properties of the material wherein ~ .
flame hardening means for generating flames adapted to impinge on the inner tubular wall of .
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..
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the -tube bend ls moved thxough the sta-tionary tube bend al~ng a circular path of a radius corresponding substantially to the radius of curvature of the tube bend center line.
In either case, i.e. during the circular movement of the tube bend with the flame hardening ~one being kept stationary, or during the circular movement of the ~lame hardening zone with the tube bend being kept stationary, the outer surface of the tube bend is being cooled in the region of the inner tube bend portion radius.
The invention furthermore proposes a method wherein an inner lining of metallic materials having ~ continuous longitudinal slot extending along the inner arc radius of the tube bend inner wall surface is being shrink fitted onto the inner wall surface of the heated tube bend, and the tube bend is moved along a circular path of a radius corresponding sub-stantially to the radius of curvature of the tube bend center line over stationary flame hardening means so that the stationary --flame hardening means will be disposed within the inner cavity of the tube bend and the flames of the hardening means impinge on the inner tubular wall of the tube bend in the region of the outer circumferential tube bend radius. The flame hardening zone is designed so as not to obstruct the circular movement of the tube bend through an arc corresponding at least to the arc length of the tube bend. This method allo~s to harden the tube bend merely in the outer circumferential region which is gener-ally subject to the severest wear in service. This hardening, -~
therefore~ achieves a substantial reduction of wear. This method of surface hardening the inner surface of tube bends thus ensures that the tube bends retain a ~.............................................................................. : :
~4~
cer~ain degree of elasticity in the region oE their inner cir-cumference so that hardenin~ strains may be compensated.
The present invention furthermore proposes an apparatus for continuously surface hardening the inner surfaces of tube bends of a constant radius of curvature by means of flame har-dening, with or without modifying the core properties of the material. The proposed apparatus comprises a support frame, a shaft horizontally journalled in the support frame, a driving motor operatively coupled to the shaft, at leas-t one mounting bracket assembly mounted on the shaft and extending in a direction perpendicular thereof. The mounting bracket assembly includes means for fastening a tube bend at one of its free ends. The free end of the mounting bracXet assembly defines a circular path during rotary movement of the shaft. A stationary mounting bracket is connected at one end to the support frame and mounts at its opposite end a flame hardening burner. The flame harden-ing burner is adapted to be received within the internal cavity of a tube bend. The stationary mounting bracket is adapted to include the supply lines leading to the flame hardening burner and is of an arcuate configuration of a radius corresponding to the radius of the circular path described by the tube bend during its movement.
To allow flame hardening of tube bends of various arc radii, the mounting bracket assembly for mounting a tube bend includes a guide slee~e whereby the radial extension of the mounting bracket assembly is adjustable so as to adapt the same to the radius of curvature of the tube bend.
.. . :: . .. . ~ -me-thod and appara-tus o~ the above type which are hiyhly economical.
It is a further object of the invention to provide ~ -method and apparatus of the above type allowing to selectively harden the outer circumferential region of tube bends since this outer region is subject to the heaviest wear during service of the tube bends. By selective hardening in this manner -the tube bends retain a certain degree of elasticity in the region of their inner radius or circumerence so that harden.ing strainsmay be compensated. ~ .
The present invention now proposes a metho~ of continu- ~ .
ously surface hardening the inner surface of tube bends of a constant radius of curvature by means of flame harden.ing wherein : : :
the tube bend is moved along a circular path of a radius corres- - ~.
ponding substantially to the radius of curvature of the tube .
bend center line over stationary flame hardening means so that the stationary flame hardening means will be disposed within the inner cavity of the tube bend and the flames of the hardening means impinge on the inner tubular wall of the tube bend.
Thereby the tube bend may be moved from an uppermost initial position through a flame hardening zone located in a laterally displaced position which is lower than the uppermost initial position of the tube bend movement. ..
The invention furthermore proposes a method of continu- .
ously surface hardening the:inner surface of tube bends of a constant radius of curvature by means of flame hardening, with or without modifying the core properties of the material wherein ~ .
flame hardening means for generating flames adapted to impinge on the inner tubular wall of .
--3~
..
'- .' , .. .
the -tube bend ls moved thxough the sta-tionary tube bend al~ng a circular path of a radius corresponding substantially to the radius of curvature of the tube bend center line.
In either case, i.e. during the circular movement of the tube bend with the flame hardening ~one being kept stationary, or during the circular movement of the ~lame hardening zone with the tube bend being kept stationary, the outer surface of the tube bend is being cooled in the region of the inner tube bend portion radius.
The invention furthermore proposes a method wherein an inner lining of metallic materials having ~ continuous longitudinal slot extending along the inner arc radius of the tube bend inner wall surface is being shrink fitted onto the inner wall surface of the heated tube bend, and the tube bend is moved along a circular path of a radius corresponding sub-stantially to the radius of curvature of the tube bend center line over stationary flame hardening means so that the stationary --flame hardening means will be disposed within the inner cavity of the tube bend and the flames of the hardening means impinge on the inner tubular wall of the tube bend in the region of the outer circumferential tube bend radius. The flame hardening zone is designed so as not to obstruct the circular movement of the tube bend through an arc corresponding at least to the arc length of the tube bend. This method allo~s to harden the tube bend merely in the outer circumferential region which is gener-ally subject to the severest wear in service. This hardening, -~
therefore~ achieves a substantial reduction of wear. This method of surface hardening the inner surface of tube bends thus ensures that the tube bends retain a ~.............................................................................. : :
~4~
cer~ain degree of elasticity in the region oE their inner cir-cumference so that hardenin~ strains may be compensated.
The present invention furthermore proposes an apparatus for continuously surface hardening the inner surfaces of tube bends of a constant radius of curvature by means of flame har-dening, with or without modifying the core properties of the material. The proposed apparatus comprises a support frame, a shaft horizontally journalled in the support frame, a driving motor operatively coupled to the shaft, at leas-t one mounting bracket assembly mounted on the shaft and extending in a direction perpendicular thereof. The mounting bracket assembly includes means for fastening a tube bend at one of its free ends. The free end of the mounting bracXet assembly defines a circular path during rotary movement of the shaft. A stationary mounting bracket is connected at one end to the support frame and mounts at its opposite end a flame hardening burner. The flame harden-ing burner is adapted to be received within the internal cavity of a tube bend. The stationary mounting bracket is adapted to include the supply lines leading to the flame hardening burner and is of an arcuate configuration of a radius corresponding to the radius of the circular path described by the tube bend during its movement.
To allow flame hardening of tube bends of various arc radii, the mounting bracket assembly for mounting a tube bend includes a guide slee~e whereby the radial extension of the mounting bracket assembly is adjustable so as to adapt the same to the radius of curvature of the tube bend.
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The mounting bracket assembly for a tube bend includes an angle of substantially 70 wlth a horizontal line in the plane of the circular path. The arcuate mounting bracket for the flame hardening burner extends through an arc of about 12~
~ccording to another characteristic of the presen-t invention, the flame hardening burner may be releasably connec~ed to the mounting bracket and may be replaced by a flame hardening burner of a different outer radius.
For cooling the inner circumferen-tial bend portion, the mounting bracket assembly for a tube bend furthermore mounts a cooling-water pipe in the vicinity of the inner circumferential tube bend portion, and thi.s cooling-water pipe includes a plurality of cooling-water discharge nozzles directed towards ;~
the inner arc tube end surface.
According to another embodiment of the inventive apparatus, a shaft is journalled in a support frame and adapted to be rotated by a driving motor, a mounting rod is mounted on the shaft and ex-tends in a direction perpendicular thereto, a mounting bracket is connected to the free end of the mounting rod, the flame hardening burner is connected to the free end of the mounting bracket, the mounting bracket is adapted to include the suppl~ lines for the flame hardening burner, and a stationary mounting arm for attachment ofa tube bend is connected to the support frame.
The method of flame hardening tube bends and the corresponding appara~us as proposed by the present invention allow the inner surface hardening of tube bends. When the tube bend moves along a circular path over a stationary : , -6- `~
flame hardening device, or when with a stationary tube bend the flame hardening device slowly moves through the tube bend the inner wall surface thereof will be hardened.
By this inner hardening the tube bends are ren~ered wear-resistant for the service in conveyor pipes adapted forpneumatic or hydraulic conveyance of abrasive materials.
Further charac~.eristics and -the advantages of the present invention will be described in the following with reference to the embodiments shown in the appended drawings wherein FIGURE 1 is; a~schomatical lateral elevdtional view of an embodiment of the inventive tube bend flame hardening apparatus showing a tube bend adapted to be moved along a circular path and a stationary flame hardening burner;
FIGURE 2 is a schematical lateral elevational view of another embodimen-t of a tube bend flame hardening apparat-us in accordance with the present invention showing a flame hardening burner adapted to be moved along a circular path corresp~nding to the mean r~dius of curvature of the tube bend and a stationary tube bend; ~
FIGURE 3 is an elevational view of a composite material tube bend, looking into one end of the tube bend;
FIGURE 4 is a schematical lateral elevational view of another embodiment of the inventive apparatus;
FIGURE 5 is a schematical lateral elevational view of still another em~odiment of the flame hardening apparatus comprisLng~a plura1ity of arcuate1y arranged burner segments adapted~to be ~adjusted with respect to th ir abùtment against a tube bend inner wall surface;
and .. . . . .. , , . ~.
FIGURE 6 is a schematical lateral elevational view of still a further embodiment of the inventive flame hardening apparatus of FIG. 5 but wherein the individual burner segments are hingedly interconnPcted.
S Referring first to FIG. 1, the embodiment of the surface hardening apparatus shown therein includes a support frame indicated generally by the reference numeral 10. A shaft 11 is journalled in horizontal direction in the support frame 10. ~he shaft 11 is operatively coupled to a drivlng .
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motor 15. The drive arrangement consis~s of a drive pulley 12 connected to the shaft ll and a driving belt 16 coupling the driving motor 15 to the dri~e pulley 12.
At one end of the shaft ll is mounted a mounting plate 20 caxrying at least one mounting bracket assembly 25 for holding a tube bend lO0 intended to be flame hardened along its inner surEace. To this end, the free end of the mounting bracke-t assembly 25 includes a clamp type fastener member 28 adapted to clamp the tube bend at one free end thereof. 'rhe longitudinal e~tension of the mounting bracket assembly 25 is adjustable in the radial direction.
To this end the mounting plate 20 mounts a guide sleeve 26 in which is telescopically guided a mounting extension 27. The mounting extension 27 may be telescopically moved inwardly or outwardly with respect to the guide sleeve 26 and may be blocked in any desired extended position by suitable means not shown in detail. The drive shaft 11 serves to move the tube bend lO0 along a circular path designated generally by U, in the direction of the arrow X. The outer circumferential arc tube bend portion is indicated at ]01, and the inner circumferential arc tube bend portion at 102. The tube bend 100 may be moved along the circular path U of a radius corresponding to the mean radius of the tube bend, i.e. the radius of the tube bend center line.
The longitudinal adjustability of the mounting bracket assembly 25 allows to adapt the apparatus to different tube bend radii so that for rotational movement o the shaft ll in the direction of the arrow X the tube bend 100 will be moved along a path corresponding to its mean radius. The mounting bracket assembly for the tube bend 100 includes :
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an angle ~f substantially 70 with a horizontal line in the plane of the circular path.
The mounting bracket asse~bly 25 is furthermore provided with a cooling device indicated at 50. This cooling device 50 is supplied as indi~ated at K with cool-ing-water for cooling the inner circumferential tube bend portion 102 of the tube bend lOO. This cooling device 50 includes a pressuri~ed water pipe of a conflguration suit-ably adapted to the configuration of the inner circumferen-tial arc tube bend portion 102 of the tube bend lOO. The pressurized water pipe includes a plurality of cooling-water discharge no~æles facing ~he outer wall of the tube bend 100 opposite the inner circumferential portion 102 thereof.
In the circular path U of the tube bend 100 is stationarily mounted a flame hardening burner 30 which may be of a conventional design. The flame hardening burner 30 is mounted at the free end 40a of an arcuate mounting brac~et 40 connected at its other end 40b to the support : .
frame 10. The moun~ing bracket 40 may be con~ected in any suitable manner at 41 to the :upport frame 10. The arcuate mounting bracket 40 may consist of a pipe having a radius -~
corresponding to tXe mean radius of the tube bend so that the arruate longitudinal center line of the mounting bracket coincides with the circular path U. Within the mounting bracket 40 are arranged the supply lines Y for the flame hardening burner 300 The flame hardenin8 burner ~ - ;
30 includes a pl~rali~y of flame orifices radially spaced ;~
about its circumfere~ceO The flames are emitted from the burner in a radial direction as indicated by the arrows y a~d may therefore impi~ge on the inner surface of the ~ube ~ -"
-- 1 0 -- - ., .
-".
- . . . ; . , . : . . : .
6~3L8 bend lO0 when the latter is being mov~d o~er the flame hardening burner 30. Th~ dimensions of the flame harden-ing burner 30 are selected such that the flame hardening burner 30 slowly "passes" through the internal cavity of the tube bend 100 when the latter is being moYed oYer the flame hardening means.
For surface hardening, the tube bend intended to be hardened is moved at a predstenmined angular velocity over the flame hardening burner 30. FDr subsequent quench-ing~ the flame hardening burner 30 includes a plurality of cooling-water discharge noæ~les (not shown~ which are connected to a likewise not shown pressurized water pipe for the s~pply of pressurized cooling-water~ The flames emerge from the burner in radial directions and impinge almost perpendicularly on the inner surface of the tube bend~ In order that the water diæcharged fro~ the water sprinkler of the flame hardenin8 burner 30 will run off downwardly~ the tube bend 100 is mo~ed ov~r the flame hardening burner 30 from an initial top oder uppermost position as shown in Fig. l, and the flame hardening burner 30 is arranged in a sidewardly displaced position that is ;.:
lower than the initial top position of the circular path -of movement of the tube bend 100. The longi~udinal ex-tension of the arcuate mounting bracket 40 bearing at its upper end the flame hardening burner 30 corresponds a~
least to the longitudinal extension of the tube bend 100 so that the latter may be moved along its full length over .
the stationary flame hartening b~rner 30. The mounting bracket 40 bearing the flame hardening b~rner 30 may be releasably connected to the support frame lO so as to ~ `
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allow the xeady replacemen,t thereo~ against mounting brackets of a different arc curvature or mounting a different type of flame hardening burner.
For compensating the different duration of flame treatment which is caused quite naturally by the smaller radius of curvature in the region of the inner circum-ferential tube bend por1:ion 102, this region may be cooled externally by means of the cooling device 50 which discharges cooling-water against the outer surace of the tube bend inner circumference. This cooling results in the effect that this region will not b,e hardened and hardening strains will be compensated.`'Experienoe has shown that this inner circumferential tube bend portion is virtually not subjqct to any appreciable abrasive wear, quite in contrast to the inner surface portion in the region of the outer circum-ference of the tube bend.
The mou~,ting plate 20 may likewise be provided with more than one mounting bracket assembly 25 in thus allowing in combination with associated correspondingly arra,nged flame hardenin~ burners several tube bends to be surface hardened simultaneously at their~inner surfaces.
~eferring to FIG. 2, there is shown an embodiment in which the conb;ination of a movable tube bend and a sta~ionary ~lame hardening burner is reversed, i.e. the .
flame hardening burner may be moved along a circular path, and the tube bend lS kept s-tationary. Toward this end, ', the tube bend 100 is attached at one of its ree ends by ~ -a mounting arm 150'to ~he support frame 10 whereas the ~;
fl~ne hardening burner 30 which is of a configuration .
; 30 similar to the en~odiment ~f FIG. 1 is connected to the .
:
~,, .
-12- ' ..
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~ree end 140a of a mounting bracket 140. A mounting rod 125 is connected at its free end 125a to the other free end 140b of the mounti~g bracket 140~ This mounting rod 125 is rigidly secured to the drive shaft 11~ in a maDner similar to the mounting bracket assembly 25 of FIG. 1~
The mounting bracket 140 including the supply lines V for the flame hardening burner 30 may in this embodiment be moved along the circular path U in the direction of the arrow X~ and ehe radius of this circular path U corr~sponds to the mean radius of the ~ube bend 100, i.e. to the radius of the tube bend center lineO The flame hardening burner 30 may ~herefore be passed through the interior ca~ity of the tube bend 100 whereby the latter is kept stationary in the position shown in FIG. 2. In this position the cool-ing-water discharged by the water sprinkler of the flame hardening burner 30 may flow away in a downward direction so that no water may accu~ulate within the in~ernal cavity ~ -~
of the tube bendO As in the embodiment of FIG. 1 the ou~er wall of the tube bend 100 is being cDoled in the region of the inner circumference 102. The longitudinal extension of the mou~ting bracket 140 is somewhat greater than ~he longi~udinal extension of the tube bend so that the flame hardening zone may be ~oved through the full length of the tube bend internal cavity.
As shown in FIG. 3~ the tube bend 100 may comprise an inner lining 110 of met~llic materials. This inner lining 110 usually includ s a continuous longitudinal slot 105 and is shrunk fit onto the inner wall surface of the eube bend 100~ The s~rlnk fitting of the linin~ i8 carried out in the heated condition of the tube bend 100 so that af~er .' .
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cooling of the tube bend the inner lining 110 is press-fitted into the tube bend. The longitudinal slot 105 engages the inner wall surface of the tube bend substantial-ly at the inner circumference or the inner arc tube bend portion~ This method of fitting inner linings is not intend-ed ~o be restrict2d merely to tube bends but may likewise be employed in the fitting of inner linings to s~rai~ht pipes or tubes.
The embodiment of the flame hardening apparatus shown in FIG. 4 includes a support frame 10 in which a shaft 11 i5 horizontally Journalled. A driving motor 15 is operatively coupled to the shaft 11~ This drive connect-ion includes a drive pulley 12 and a drivlng belt 16.
A moun~ing arm 150 is rigidly secured to the support fra~e 10 and is adapted to attach at its free end a tube bend 100 intended to be hardened. The tube bend 100 is ~onne~ed by one of Its free ends ~o the free end of the mounting arm 150.
A mounting plate 20 is secured to one end of the shaft 11 and mounts a mounting rod 125~ A cooling device 50 is connected to the free end of the mounting ~od 125.
A flame hardening burner 30 is connected to the free end ~-of the cooling device 50. The flame hardenin8 burner 30 and the cooling device 50 both co~sist of interconnected tube bends of an ou~er diameter in cross~direction which i is somewhat smaller than the inner diameter in cross-direction of a tube bend 100 intended to be hardened so ~hat ~he flame hardening burner 30 and the cooling device 50 may be introduced into the internal cavity ~f the tube bend 100. By means of the shaft 11, the mounting plate 20 and the mounting rod 125 the flame hardening burner 30 and the cooling device 50 may be moved along a circula~
path U corresponding to the mean radius of curvature of a tube bend 100 intendPd to be hardened whereby both devices may be moved through the internal cavity of the tube bend in the direction of the arrow X. The flame hardening burner 30 is separated from the cooling device 50 by a partition wall 160.
The flame hardening burner 30 may be of any suit~
able conventional design and includes a plurality of fla~
orifices radially spaced about its circumference so that the flames radially e~erging from the flame hardening burner 30 will impinge on the inner wall surface of the tube bend 100 when introducing ~he flame hardening burner 30 into the internal cavity of the tube bend 100. The flame harden-ing burner 30 may be passed slowly through the internal : cavity of the tube bend 100 until the cooling ~one is about to enter the tube bend and ~111 likewise be passPd through ; :
the tube bend. Alternatively, the flame hardenlng burner 30 may be introduced in an inactive condition into the internal cavity of the tube bend 100 and subsequently put into service. The longitudinal extension of the flame hardening burner 30 would then substantially correspond to - the longitudinal extension of the tube bend 100~ The longitudinal extension of the cooling device 50 likewis substantially corresponds to the longitudinal e~tension of the tube bend 100 so that after introducing the flame - harde~ing burner 30 into the internal cavity of the tube bend 100 the latter may be flame hardened along the full longitudinaI extension of the inner surface of the tube ' .
- 15 .
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The mounting bracket assembly for a tube bend includes an angle of substantially 70 wlth a horizontal line in the plane of the circular path. The arcuate mounting bracket for the flame hardening burner extends through an arc of about 12~
~ccording to another characteristic of the presen-t invention, the flame hardening burner may be releasably connec~ed to the mounting bracket and may be replaced by a flame hardening burner of a different outer radius.
For cooling the inner circumferen-tial bend portion, the mounting bracket assembly for a tube bend furthermore mounts a cooling-water pipe in the vicinity of the inner circumferential tube bend portion, and thi.s cooling-water pipe includes a plurality of cooling-water discharge nozzles directed towards ;~
the inner arc tube end surface.
According to another embodiment of the inventive apparatus, a shaft is journalled in a support frame and adapted to be rotated by a driving motor, a mounting rod is mounted on the shaft and ex-tends in a direction perpendicular thereto, a mounting bracket is connected to the free end of the mounting rod, the flame hardening burner is connected to the free end of the mounting bracket, the mounting bracket is adapted to include the suppl~ lines for the flame hardening burner, and a stationary mounting arm for attachment ofa tube bend is connected to the support frame.
The method of flame hardening tube bends and the corresponding appara~us as proposed by the present invention allow the inner surface hardening of tube bends. When the tube bend moves along a circular path over a stationary : , -6- `~
flame hardening device, or when with a stationary tube bend the flame hardening device slowly moves through the tube bend the inner wall surface thereof will be hardened.
By this inner hardening the tube bends are ren~ered wear-resistant for the service in conveyor pipes adapted forpneumatic or hydraulic conveyance of abrasive materials.
Further charac~.eristics and -the advantages of the present invention will be described in the following with reference to the embodiments shown in the appended drawings wherein FIGURE 1 is; a~schomatical lateral elevdtional view of an embodiment of the inventive tube bend flame hardening apparatus showing a tube bend adapted to be moved along a circular path and a stationary flame hardening burner;
FIGURE 2 is a schematical lateral elevational view of another embodimen-t of a tube bend flame hardening apparat-us in accordance with the present invention showing a flame hardening burner adapted to be moved along a circular path corresp~nding to the mean r~dius of curvature of the tube bend and a stationary tube bend; ~
FIGURE 3 is an elevational view of a composite material tube bend, looking into one end of the tube bend;
FIGURE 4 is a schematical lateral elevational view of another embodiment of the inventive apparatus;
FIGURE 5 is a schematical lateral elevational view of still another em~odiment of the flame hardening apparatus comprisLng~a plura1ity of arcuate1y arranged burner segments adapted~to be ~adjusted with respect to th ir abùtment against a tube bend inner wall surface;
and .. . . . .. , , . ~.
FIGURE 6 is a schematical lateral elevational view of still a further embodiment of the inventive flame hardening apparatus of FIG. 5 but wherein the individual burner segments are hingedly interconnPcted.
S Referring first to FIG. 1, the embodiment of the surface hardening apparatus shown therein includes a support frame indicated generally by the reference numeral 10. A shaft 11 is journalled in horizontal direction in the support frame 10. ~he shaft 11 is operatively coupled to a drivlng .
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;
":
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' ':
,'.
motor 15. The drive arrangement consis~s of a drive pulley 12 connected to the shaft ll and a driving belt 16 coupling the driving motor 15 to the dri~e pulley 12.
At one end of the shaft ll is mounted a mounting plate 20 caxrying at least one mounting bracket assembly 25 for holding a tube bend lO0 intended to be flame hardened along its inner surEace. To this end, the free end of the mounting bracke-t assembly 25 includes a clamp type fastener member 28 adapted to clamp the tube bend at one free end thereof. 'rhe longitudinal e~tension of the mounting bracket assembly 25 is adjustable in the radial direction.
To this end the mounting plate 20 mounts a guide sleeve 26 in which is telescopically guided a mounting extension 27. The mounting extension 27 may be telescopically moved inwardly or outwardly with respect to the guide sleeve 26 and may be blocked in any desired extended position by suitable means not shown in detail. The drive shaft 11 serves to move the tube bend lO0 along a circular path designated generally by U, in the direction of the arrow X. The outer circumferential arc tube bend portion is indicated at ]01, and the inner circumferential arc tube bend portion at 102. The tube bend 100 may be moved along the circular path U of a radius corresponding to the mean radius of the tube bend, i.e. the radius of the tube bend center line.
The longitudinal adjustability of the mounting bracket assembly 25 allows to adapt the apparatus to different tube bend radii so that for rotational movement o the shaft ll in the direction of the arrow X the tube bend 100 will be moved along a path corresponding to its mean radius. The mounting bracket assembly for the tube bend 100 includes :
- , ...... .. - . . ~ , .- ' . . . - . , ,~ ', ~ . - '.
~6g~
an angle ~f substantially 70 with a horizontal line in the plane of the circular path.
The mounting bracket asse~bly 25 is furthermore provided with a cooling device indicated at 50. This cooling device 50 is supplied as indi~ated at K with cool-ing-water for cooling the inner circumferential tube bend portion 102 of the tube bend lOO. This cooling device 50 includes a pressuri~ed water pipe of a conflguration suit-ably adapted to the configuration of the inner circumferen-tial arc tube bend portion 102 of the tube bend lOO. The pressurized water pipe includes a plurality of cooling-water discharge no~æles facing ~he outer wall of the tube bend 100 opposite the inner circumferential portion 102 thereof.
In the circular path U of the tube bend 100 is stationarily mounted a flame hardening burner 30 which may be of a conventional design. The flame hardening burner 30 is mounted at the free end 40a of an arcuate mounting brac~et 40 connected at its other end 40b to the support : .
frame 10. The moun~ing bracket 40 may be con~ected in any suitable manner at 41 to the :upport frame 10. The arcuate mounting bracket 40 may consist of a pipe having a radius -~
corresponding to tXe mean radius of the tube bend so that the arruate longitudinal center line of the mounting bracket coincides with the circular path U. Within the mounting bracket 40 are arranged the supply lines Y for the flame hardening burner 300 The flame hardenin8 burner ~ - ;
30 includes a pl~rali~y of flame orifices radially spaced ;~
about its circumfere~ceO The flames are emitted from the burner in a radial direction as indicated by the arrows y a~d may therefore impi~ge on the inner surface of the ~ube ~ -"
-- 1 0 -- - ., .
-".
- . . . ; . , . : . . : .
6~3L8 bend lO0 when the latter is being mov~d o~er the flame hardening burner 30. Th~ dimensions of the flame harden-ing burner 30 are selected such that the flame hardening burner 30 slowly "passes" through the internal cavity of the tube bend 100 when the latter is being moYed oYer the flame hardening means.
For surface hardening, the tube bend intended to be hardened is moved at a predstenmined angular velocity over the flame hardening burner 30. FDr subsequent quench-ing~ the flame hardening burner 30 includes a plurality of cooling-water discharge noæ~les (not shown~ which are connected to a likewise not shown pressurized water pipe for the s~pply of pressurized cooling-water~ The flames emerge from the burner in radial directions and impinge almost perpendicularly on the inner surface of the tube bend~ In order that the water diæcharged fro~ the water sprinkler of the flame hardenin8 burner 30 will run off downwardly~ the tube bend 100 is mo~ed ov~r the flame hardening burner 30 from an initial top oder uppermost position as shown in Fig. l, and the flame hardening burner 30 is arranged in a sidewardly displaced position that is ;.:
lower than the initial top position of the circular path -of movement of the tube bend 100. The longi~udinal ex-tension of the arcuate mounting bracket 40 bearing at its upper end the flame hardening burner 30 corresponds a~
least to the longitudinal extension of the tube bend 100 so that the latter may be moved along its full length over .
the stationary flame hartening b~rner 30. The mounting bracket 40 bearing the flame hardening b~rner 30 may be releasably connected to the support frame lO so as to ~ `
.
3~
allow the xeady replacemen,t thereo~ against mounting brackets of a different arc curvature or mounting a different type of flame hardening burner.
For compensating the different duration of flame treatment which is caused quite naturally by the smaller radius of curvature in the region of the inner circum-ferential tube bend por1:ion 102, this region may be cooled externally by means of the cooling device 50 which discharges cooling-water against the outer surace of the tube bend inner circumference. This cooling results in the effect that this region will not b,e hardened and hardening strains will be compensated.`'Experienoe has shown that this inner circumferential tube bend portion is virtually not subjqct to any appreciable abrasive wear, quite in contrast to the inner surface portion in the region of the outer circum-ference of the tube bend.
The mou~,ting plate 20 may likewise be provided with more than one mounting bracket assembly 25 in thus allowing in combination with associated correspondingly arra,nged flame hardenin~ burners several tube bends to be surface hardened simultaneously at their~inner surfaces.
~eferring to FIG. 2, there is shown an embodiment in which the conb;ination of a movable tube bend and a sta~ionary ~lame hardening burner is reversed, i.e. the .
flame hardening burner may be moved along a circular path, and the tube bend lS kept s-tationary. Toward this end, ', the tube bend 100 is attached at one of its ree ends by ~ -a mounting arm 150'to ~he support frame 10 whereas the ~;
fl~ne hardening burner 30 which is of a configuration .
; 30 similar to the en~odiment ~f FIG. 1 is connected to the .
:
~,, .
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~ree end 140a of a mounting bracket 140. A mounting rod 125 is connected at its free end 125a to the other free end 140b of the mounti~g bracket 140~ This mounting rod 125 is rigidly secured to the drive shaft 11~ in a maDner similar to the mounting bracket assembly 25 of FIG. 1~
The mounting bracket 140 including the supply lines V for the flame hardening burner 30 may in this embodiment be moved along the circular path U in the direction of the arrow X~ and ehe radius of this circular path U corr~sponds to the mean radius of the ~ube bend 100, i.e. to the radius of the tube bend center lineO The flame hardening burner 30 may ~herefore be passed through the interior ca~ity of the tube bend 100 whereby the latter is kept stationary in the position shown in FIG. 2. In this position the cool-ing-water discharged by the water sprinkler of the flame hardening burner 30 may flow away in a downward direction so that no water may accu~ulate within the in~ernal cavity ~ -~
of the tube bendO As in the embodiment of FIG. 1 the ou~er wall of the tube bend 100 is being cDoled in the region of the inner circumference 102. The longitudinal extension of the mou~ting bracket 140 is somewhat greater than ~he longi~udinal extension of the tube bend so that the flame hardening zone may be ~oved through the full length of the tube bend internal cavity.
As shown in FIG. 3~ the tube bend 100 may comprise an inner lining 110 of met~llic materials. This inner lining 110 usually includ s a continuous longitudinal slot 105 and is shrunk fit onto the inner wall surface of the eube bend 100~ The s~rlnk fitting of the linin~ i8 carried out in the heated condition of the tube bend 100 so that af~er .' .
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_ 13 -. -: . . .
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cooling of the tube bend the inner lining 110 is press-fitted into the tube bend. The longitudinal slot 105 engages the inner wall surface of the tube bend substantial-ly at the inner circumference or the inner arc tube bend portion~ This method of fitting inner linings is not intend-ed ~o be restrict2d merely to tube bends but may likewise be employed in the fitting of inner linings to s~rai~ht pipes or tubes.
The embodiment of the flame hardening apparatus shown in FIG. 4 includes a support frame 10 in which a shaft 11 i5 horizontally Journalled. A driving motor 15 is operatively coupled to the shaft 11~ This drive connect-ion includes a drive pulley 12 and a drivlng belt 16.
A moun~ing arm 150 is rigidly secured to the support fra~e 10 and is adapted to attach at its free end a tube bend 100 intended to be hardened. The tube bend 100 is ~onne~ed by one of Its free ends ~o the free end of the mounting arm 150.
A mounting plate 20 is secured to one end of the shaft 11 and mounts a mounting rod 125~ A cooling device 50 is connected to the free end of the mounting ~od 125.
A flame hardening burner 30 is connected to the free end ~-of the cooling device 50. The flame hardenin8 burner 30 and the cooling device 50 both co~sist of interconnected tube bends of an ou~er diameter in cross~direction which i is somewhat smaller than the inner diameter in cross-direction of a tube bend 100 intended to be hardened so ~hat ~he flame hardening burner 30 and the cooling device 50 may be introduced into the internal cavity ~f the tube bend 100. By means of the shaft 11, the mounting plate 20 and the mounting rod 125 the flame hardening burner 30 and the cooling device 50 may be moved along a circula~
path U corresponding to the mean radius of curvature of a tube bend 100 intendPd to be hardened whereby both devices may be moved through the internal cavity of the tube bend in the direction of the arrow X. The flame hardening burner 30 is separated from the cooling device 50 by a partition wall 160.
The flame hardening burner 30 may be of any suit~
able conventional design and includes a plurality of fla~
orifices radially spaced about its circumference so that the flames radially e~erging from the flame hardening burner 30 will impinge on the inner wall surface of the tube bend 100 when introducing ~he flame hardening burner 30 into the internal cavity of the tube bend 100. The flame harden-ing burner 30 may be passed slowly through the internal : cavity of the tube bend 100 until the cooling ~one is about to enter the tube bend and ~111 likewise be passPd through ; :
the tube bend. Alternatively, the flame hardenlng burner 30 may be introduced in an inactive condition into the internal cavity of the tube bend 100 and subsequently put into service. The longitudinal extension of the flame hardening burner 30 would then substantially correspond to - the longitudinal extension of the tube bend 100~ The longitudinal extension of the cooling device 50 likewis substantially corresponds to the longitudinal e~tension of the tube bend 100 so that after introducing the flame - harde~ing burner 30 into the internal cavity of the tube bend 100 the latter may be flame hardened along the full longitudinaI extension of the inner surface of the tube ' .
- 15 .
4~L8 bend. ~pon con~pletion of flame hardening, the entire movable assembly consisting of flame hardening burner 30 and ~ooling device 50 will be moYed further in the direction of the arrow X in thereby introducing the cooling device 50 incrementally into the internal cavity of the tube bend 100.
The mounting rod 125 includes the supply lines V
leading to the flame hardening burner 30 and ~o the cooling device 50. The cooling device S0 is supplied with pressurized cooling-water. As soon as the cooling device 50 has been introduced fully into the internal cavity of the tube bend 100, quenching has been 2chieved. Then the movable assembly consisting of flame hardenlng burner 30 ~ -and cooling device 50 is rotated in a sense opposite to the arrow X back into the ini~ial position shown in ~IG. 4.
After mounting of another untreated tube bend within the mounting 150 the above described cycle may be repeated.
In the latter embodiment the flame hardening burner 30 may be moved together with the cooling device 50 along the circular path U which coincides with the radius of the center line of~the tube bend 100.
The embodiment of the apparatus shown in FIG. 4 ; ~
allows to either harden the whole inner surface oE the tube ~ ;
bend in one operation, i.e. all surface portions simultan- -~
eously by initially ro~a~ing the flame hardening burner 30 so that the burner extends with its full length within the intern~l caYity of the tube bend 100, or to incremen~ally harden adjoining si~face portions of ~he tube bend inner ~urface by slo~ly moving the flame hardening burner into ~ ;
the internal cavity of the ~ube bend~ In the latter me~hod '.
...
~ 16 -~ ,. . . ... . . . . . . . .... .. . . . .. .... . . . . ... .. . . . .. . . . .
will be obtained the advanta~e of a certain post-hardening in those regions which have already been hardened when the flame hardening burner 30 has been moved into -the tube ben~.
Since the cooling region is disposed immediately behind the flame hardening burner 30, the tube bend may be quenched immediately after heating. Since the tube bend 100 is kept stationary in the position shown in Fig. 4 the cooling-wa-ter discharged from the cooling device 50 may flow downwardly and out of the tube bend so that no water will collect wi-thin the internal cavity of the tube bend.
.
~;';, -17- `
In -the embodiment of the inventive appara-tus for the surface hardening of tube bends by locally heat-ing the layers adjacent the interior surface of the tube bends the reference numeral 30 designates a flame harden-S ing burner consisting of a plurality of individual burner segments such as the segments 31l 32, 33, 34, 35, 36 and 37 that are arranged in a substantially circular con-figuration and are mutually interconnected. Of these burner segments 31 through 37, a centrally disposed burner segment 31 is connected to a mounting hub 200. The mount-ing hub 200 is disposèa centr?lly of the space inside the tube bend and is connected to means (not shown) for pass-ing the flame hardening burner 30 through the internal cavity circumscribed by the tube bend which is generally indicated at 100.
~ A pair of arcuate mounting arms 230, 231 are each ; mounted at their upper ends 230a, 231a to the burner segment 31 which in turn is rigidly connected to the mounting hub 200. The~two mounting arms 230, 231 are mounted, at ~their respective ends~230a,~ 231a, at the burner segment 31 in a manner so that the mounting arms 230, 231 may be pivoted about their mountings. The corresponding pivots are indicated in Fig. 5 at 240 and 241 respectively. Both mounting arms 230,~231 are of equal length and of sub-stantial similar configura~tion. ~he lengths of the mount-. . ~
ing arms 230, 231~arè selected so that the moun~ing arms do not define a complete circle. Therefore, the lower ~free ends~230b,~231b of the two mounting arms 230, 231 are mutually spaced, and~the two mounting arms 230, 231 :~ :
~ 30 may be pivoted about~the~.r respective pivots ~240, 241.
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In the normal positlon, the mounting arms 230, 231 define, together with the burner segment 31, an arc which sub-stantially coincides with the longitudirlal centerline of the tube bend 100.
The further burner segments 32, 33, 34, 35, 36 and 37 are mounted on the two mounting arms 230, 231 whereby the mounting arm 230 mounts the burner segments 35, 36, and 37, and the mounting arm 231 mounts the burner segments 32, 33 and 34. Since the burner segments 32 through 37 are rigidly mounted on the mounting arm 230 or the mounting arm 231 respectively, the outer wall surfaces of the burner segments may be adjusted at different spacings from the tube bend inner wall surface, by merely rotating the mounting arms 230, 231 about their respective pivots 240, 241. In the position shown in FIG. 5, the burner segments 31 through 37 engage, with their outer wall surfaces, the inner wall surface of the tube bend 100, i.e. the diameter of the arcuate flame hardening burner 30 has been designed so that all burner segments 31 through ~.
:~ 20 37 are equally spac d from the tube bend inner wall surface.
Each burner segment 31 through 37 of the flame hardening burner 30 comprises in its outer wall surface a plurality of flame orifices whereby the flames emitted from the burner segments impinge upon the inner wall : :
surface of the tube bend 100 whilst the flame hardening burner 30 is being passed through the internal cavity of the tube bend 100. The mounting hub 200 also includes the main supply line connections for feeding the burner gas mixture to the flame hardening burner. The individual ~ .
burner ~egments 31 throuyh 37 are connected to the main supply line V, via individual supply line branches 290.
Every burner segment 31 through 37 of the annular flame hardening burner 30 is furthermore provided with a cooling device generally indicated at 50. The supply lines 290 also include feed and return lines for the cooling ~luid.
The two mounting arms 230, 231 are interconnected, at their free lower ends 230b, 231b, by a spacer assembly 250. This spacer assembly 250 serves to adjust the mutual distance of the fr~e ~pwer ends 230b, 231b or the two mounting arms 230, 231, by piv-oting the same about their pivots 240, 241 respectively in the directions indicated ; by the arrows x and xl respectively. In this manner, the spacing of the burner segments 31 through 37 from the inner wall surface of the tube bend 100 is altered and may be adjusted so that the flames exiting from the burner segments 31 through 37 ev nly impinge upon the tube bend inner wall surface and even hardening of this inner wall surface may be obtained.
~ The spacer asse~bly 250 includes a threaded spindle 251 that engages at its two opposing threaded ends corresponding threaded openings in mounting plates 252, 253. The mounting plates 252, 253 are respectively mounted at the bent free ends of the mounting arms 230, 231. ~Substantially~in its central portion, the threaded spindle 251 includes a wor~ gear 254 that consists of a worm wheel 254a engaging a worm 254b, as is conventional.
The worm 254b engaging the worm wheel 254a is secured to a flexible drive shaft~255. Both -free ends of the : : :
threaded splndle 251, at either side of the worm gear 254, include suitable threads so that when rotating the threaded spindle 251 the mutual spacing of the free ends 230b, 231b of the mounting arms 230, 231 is altered. When rotating the threaded spindle 252 in one direction the free ends 23Ob, 231b are moved towards each other, and when rotat-ing the threaded spindle 251 in the opposite direction, the free ends 230b, 231b are being moved away from each other. With this arrangement and because of the flexible drive shaft 255 the spacing oE the burner segments 31 through 37 from the inner`wall surface of the tube bend 100 may be continuously varied during a flame hardening operation, in response to tube thickness and radius of .
curvature. This spacing adjustment may be performed manually by means of the flexible drive shaft 255. Alter- .
nately, the spacing adjustment may be carried out by means : of a drive motor (not shown) connected to a suitable controller.
In the embodiment of the inventive apparatus :~
shown in FIG. 6, the flame hardening burner 30 likewise includes the burner segments 31 through 37. In this embodiment, the burner segments 31 through 37, however, are hingedly lnterconnected by means of link rods 260, 261, 262, 263, 264 and 265 respectively. Each individual burner segment is connected to the central mounting hub 200 by~a holding arm 270,~271, 272, 273, 274, 275 and 276 respectively. These holding arms 270 through 276 serve to normally urge:the burner segments 31 through 37 auto- .
matically against the inner wall surface of the tube bend 100, during a flame~hardening treatment~ Spacer : , .~'..
cams 300 are secured to the outer circumference of the burner segments 31 through 37 and allow to obtain a pre-determined spacing between the burner segments 31 through 37 and the inner wall surface o~ the tube bend 100. The spacer cams 300 are preferably adjustable in length. The automatic urging of the individual burner segments 31 through 37 agains~ the tube bend inner wall surface may be caused by springs 280 that are mounted internally of the holding arms 270 through 276, as shown schematically in the upper part o FIG. 6. Every holding arm may con-sist of a guide sleeve~270a in which is slidably guided a slide rod 270b whercby this slide rod is biased by a spring 280 disposed within the guide sleeve 270a.
Alternately, the holding arms 270 through 276 may consist of holding rods with outer threads. The externally threaded holdin~ rods will then operate in the manner of a spindle and the free ends of these hold-ing rods disposed in the mounting hub 200 would of course -be provided with means for rotating the holding rod to vary the spacing of the burner segments 31 through 37 from the tube bend inner wall surface.
For spacing the flame nozzle orifices of the individual burner segments, every burner segment may include spacer cams 304 by which the individual burner segments engage~the inner wall surface of a tube bend 100 being hardened.~ One of these spacer cam~ 300 on the burner segment 37 only is shown in FIG~ 6, for clarity.
Any deslred number of burner segments may be provided. ~The burner segments 31 through 37 may likewise be arranged so as to deine a closed circle. In FIG. 6 is shown at 31a in dashed lines an additional burner segment by which th~ full circle ls completed. The supply lines for the burner segments 31 through 37 and for the cooling devices 50 may also be separately pro-vided, as shown in FIG. 5 by the additional supply lines2~0a.
The inventive apparatus allows to continuously vary the spacing of the individual burner segments of the arcuate flame hardening burner from the tube inner wall ~urface during a flame hardening treatment. In this manner even.hardenin~ ~f`the inner surface of tube bends :
may be achieved. The adjustabality of the spacing of the burner segments 31 through 37 from the tube bend inner wall surface furthermore allows to employ the apparatus of the present invention likewise for the treatment of tube bends having varying inner diameters, In order to avoid any interference with the free movements of the : individual burner segments 31 through 37, the supply lines connected to these burner segments are flexible.
~:; ' ,' `.
, ' :
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-:
The mounting rod 125 includes the supply lines V
leading to the flame hardening burner 30 and ~o the cooling device 50. The cooling device S0 is supplied with pressurized cooling-water. As soon as the cooling device 50 has been introduced fully into the internal cavity of the tube bend 100, quenching has been 2chieved. Then the movable assembly consisting of flame hardenlng burner 30 ~ -and cooling device 50 is rotated in a sense opposite to the arrow X back into the ini~ial position shown in ~IG. 4.
After mounting of another untreated tube bend within the mounting 150 the above described cycle may be repeated.
In the latter embodiment the flame hardening burner 30 may be moved together with the cooling device 50 along the circular path U which coincides with the radius of the center line of~the tube bend 100.
The embodiment of the apparatus shown in FIG. 4 ; ~
allows to either harden the whole inner surface oE the tube ~ ;
bend in one operation, i.e. all surface portions simultan- -~
eously by initially ro~a~ing the flame hardening burner 30 so that the burner extends with its full length within the intern~l caYity of the tube bend 100, or to incremen~ally harden adjoining si~face portions of ~he tube bend inner ~urface by slo~ly moving the flame hardening burner into ~ ;
the internal cavity of the ~ube bend~ In the latter me~hod '.
...
~ 16 -~ ,. . . ... . . . . . . . .... .. . . . .. .... . . . . ... .. . . . .. . . . .
will be obtained the advanta~e of a certain post-hardening in those regions which have already been hardened when the flame hardening burner 30 has been moved into -the tube ben~.
Since the cooling region is disposed immediately behind the flame hardening burner 30, the tube bend may be quenched immediately after heating. Since the tube bend 100 is kept stationary in the position shown in Fig. 4 the cooling-wa-ter discharged from the cooling device 50 may flow downwardly and out of the tube bend so that no water will collect wi-thin the internal cavity of the tube bend.
.
~;';, -17- `
In -the embodiment of the inventive appara-tus for the surface hardening of tube bends by locally heat-ing the layers adjacent the interior surface of the tube bends the reference numeral 30 designates a flame harden-S ing burner consisting of a plurality of individual burner segments such as the segments 31l 32, 33, 34, 35, 36 and 37 that are arranged in a substantially circular con-figuration and are mutually interconnected. Of these burner segments 31 through 37, a centrally disposed burner segment 31 is connected to a mounting hub 200. The mount-ing hub 200 is disposèa centr?lly of the space inside the tube bend and is connected to means (not shown) for pass-ing the flame hardening burner 30 through the internal cavity circumscribed by the tube bend which is generally indicated at 100.
~ A pair of arcuate mounting arms 230, 231 are each ; mounted at their upper ends 230a, 231a to the burner segment 31 which in turn is rigidly connected to the mounting hub 200. The~two mounting arms 230, 231 are mounted, at ~their respective ends~230a,~ 231a, at the burner segment 31 in a manner so that the mounting arms 230, 231 may be pivoted about their mountings. The corresponding pivots are indicated in Fig. 5 at 240 and 241 respectively. Both mounting arms 230,~231 are of equal length and of sub-stantial similar configura~tion. ~he lengths of the mount-. . ~
ing arms 230, 231~arè selected so that the moun~ing arms do not define a complete circle. Therefore, the lower ~free ends~230b,~231b of the two mounting arms 230, 231 are mutually spaced, and~the two mounting arms 230, 231 :~ :
~ 30 may be pivoted about~the~.r respective pivots ~240, 241.
-,.
~ -18-.. ,. . . . . ,, : ., .
:~9'~
In the normal positlon, the mounting arms 230, 231 define, together with the burner segment 31, an arc which sub-stantially coincides with the longitudirlal centerline of the tube bend 100.
The further burner segments 32, 33, 34, 35, 36 and 37 are mounted on the two mounting arms 230, 231 whereby the mounting arm 230 mounts the burner segments 35, 36, and 37, and the mounting arm 231 mounts the burner segments 32, 33 and 34. Since the burner segments 32 through 37 are rigidly mounted on the mounting arm 230 or the mounting arm 231 respectively, the outer wall surfaces of the burner segments may be adjusted at different spacings from the tube bend inner wall surface, by merely rotating the mounting arms 230, 231 about their respective pivots 240, 241. In the position shown in FIG. 5, the burner segments 31 through 37 engage, with their outer wall surfaces, the inner wall surface of the tube bend 100, i.e. the diameter of the arcuate flame hardening burner 30 has been designed so that all burner segments 31 through ~.
:~ 20 37 are equally spac d from the tube bend inner wall surface.
Each burner segment 31 through 37 of the flame hardening burner 30 comprises in its outer wall surface a plurality of flame orifices whereby the flames emitted from the burner segments impinge upon the inner wall : :
surface of the tube bend 100 whilst the flame hardening burner 30 is being passed through the internal cavity of the tube bend 100. The mounting hub 200 also includes the main supply line connections for feeding the burner gas mixture to the flame hardening burner. The individual ~ .
burner ~egments 31 throuyh 37 are connected to the main supply line V, via individual supply line branches 290.
Every burner segment 31 through 37 of the annular flame hardening burner 30 is furthermore provided with a cooling device generally indicated at 50. The supply lines 290 also include feed and return lines for the cooling ~luid.
The two mounting arms 230, 231 are interconnected, at their free lower ends 230b, 231b, by a spacer assembly 250. This spacer assembly 250 serves to adjust the mutual distance of the fr~e ~pwer ends 230b, 231b or the two mounting arms 230, 231, by piv-oting the same about their pivots 240, 241 respectively in the directions indicated ; by the arrows x and xl respectively. In this manner, the spacing of the burner segments 31 through 37 from the inner wall surface of the tube bend 100 is altered and may be adjusted so that the flames exiting from the burner segments 31 through 37 ev nly impinge upon the tube bend inner wall surface and even hardening of this inner wall surface may be obtained.
~ The spacer asse~bly 250 includes a threaded spindle 251 that engages at its two opposing threaded ends corresponding threaded openings in mounting plates 252, 253. The mounting plates 252, 253 are respectively mounted at the bent free ends of the mounting arms 230, 231. ~Substantially~in its central portion, the threaded spindle 251 includes a wor~ gear 254 that consists of a worm wheel 254a engaging a worm 254b, as is conventional.
The worm 254b engaging the worm wheel 254a is secured to a flexible drive shaft~255. Both -free ends of the : : :
threaded splndle 251, at either side of the worm gear 254, include suitable threads so that when rotating the threaded spindle 251 the mutual spacing of the free ends 230b, 231b of the mounting arms 230, 231 is altered. When rotating the threaded spindle 252 in one direction the free ends 23Ob, 231b are moved towards each other, and when rotat-ing the threaded spindle 251 in the opposite direction, the free ends 230b, 231b are being moved away from each other. With this arrangement and because of the flexible drive shaft 255 the spacing oE the burner segments 31 through 37 from the inner`wall surface of the tube bend 100 may be continuously varied during a flame hardening operation, in response to tube thickness and radius of .
curvature. This spacing adjustment may be performed manually by means of the flexible drive shaft 255. Alter- .
nately, the spacing adjustment may be carried out by means : of a drive motor (not shown) connected to a suitable controller.
In the embodiment of the inventive apparatus :~
shown in FIG. 6, the flame hardening burner 30 likewise includes the burner segments 31 through 37. In this embodiment, the burner segments 31 through 37, however, are hingedly lnterconnected by means of link rods 260, 261, 262, 263, 264 and 265 respectively. Each individual burner segment is connected to the central mounting hub 200 by~a holding arm 270,~271, 272, 273, 274, 275 and 276 respectively. These holding arms 270 through 276 serve to normally urge:the burner segments 31 through 37 auto- .
matically against the inner wall surface of the tube bend 100, during a flame~hardening treatment~ Spacer : , .~'..
cams 300 are secured to the outer circumference of the burner segments 31 through 37 and allow to obtain a pre-determined spacing between the burner segments 31 through 37 and the inner wall surface o~ the tube bend 100. The spacer cams 300 are preferably adjustable in length. The automatic urging of the individual burner segments 31 through 37 agains~ the tube bend inner wall surface may be caused by springs 280 that are mounted internally of the holding arms 270 through 276, as shown schematically in the upper part o FIG. 6. Every holding arm may con-sist of a guide sleeve~270a in which is slidably guided a slide rod 270b whercby this slide rod is biased by a spring 280 disposed within the guide sleeve 270a.
Alternately, the holding arms 270 through 276 may consist of holding rods with outer threads. The externally threaded holdin~ rods will then operate in the manner of a spindle and the free ends of these hold-ing rods disposed in the mounting hub 200 would of course -be provided with means for rotating the holding rod to vary the spacing of the burner segments 31 through 37 from the tube bend inner wall surface.
For spacing the flame nozzle orifices of the individual burner segments, every burner segment may include spacer cams 304 by which the individual burner segments engage~the inner wall surface of a tube bend 100 being hardened.~ One of these spacer cam~ 300 on the burner segment 37 only is shown in FIG~ 6, for clarity.
Any deslred number of burner segments may be provided. ~The burner segments 31 through 37 may likewise be arranged so as to deine a closed circle. In FIG. 6 is shown at 31a in dashed lines an additional burner segment by which th~ full circle ls completed. The supply lines for the burner segments 31 through 37 and for the cooling devices 50 may also be separately pro-vided, as shown in FIG. 5 by the additional supply lines2~0a.
The inventive apparatus allows to continuously vary the spacing of the individual burner segments of the arcuate flame hardening burner from the tube inner wall ~urface during a flame hardening treatment. In this manner even.hardenin~ ~f`the inner surface of tube bends :
may be achieved. The adjustabality of the spacing of the burner segments 31 through 37 from the tube bend inner wall surface furthermore allows to employ the apparatus of the present invention likewise for the treatment of tube bends having varying inner diameters, In order to avoid any interference with the free movements of the : individual burner segments 31 through 37, the supply lines connected to these burner segments are flexible.
~:; ' ,' `.
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-:
Claims (23)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of continuously surface hardening the inner surface of tube bends of a constant radius of curvature by means of flame hardening with or without modifying the core properties of the material, wherein the tube bend is moved along a circular path of a radius corresponding substantially to the radius of curvature of the tube bend center line over stationary flame hardening means so that the stationary flame hardening means will be disposed within the inner cavity of the tube bend and the flames of the hardening means impinge on the inner tubular wall surface of the tube bend.
2. A method as defined in claim 1 wherein the tube bend is moved from an uppermost initial position through a flame hardening zone located in a laterally displaced position and lower than the uppermost initial position of the tube bend movement.
3. A method of continuously surface hardening the inner surface of tube bends of a constant radius of curvature by means of flame hardening, with or without modifying the core properties of the material, wherein flame hardening means for generating flames adapted to impinge on the inner tubular wall of the tube bend is moved through the stationary tube bend along a circular path of a radius corresponding substantially to the radius of curvature of the tube bend center line.
4. A method as defined in claim 1, 2 or 3, wherein during the circular movement of the tube bend with the flame hardening zone being stationary or during the circular movement of the flame hardening zone with the tube bend being stationary the outer surface of the tube bend is being cooled in the region of the inner tube bend portion radius.
5. A method as defined in claim 1, wherein an inner lining of metallic materials having a continuous longitu-dinal slot extending along the inner arc radius of the tube bend inner wall surface is being shrink fitted onto the inner wall surface of the heated tube bend, and the tube bend is moved along a circular path of a radius corresponding substantially to the radius of curvature of the tube bend center line over stationary flame hardening means so that the stationary flame hardening means will be disposed within the inner cavity of the tube bend and the flames emerging from the hardening means impinge on the inner tubular wall of the tube bend in the region of the outer circumferential tube bend radius.
6. A method as defined in claim 5 wherein the tube or respectively the tube bend is heated, then an inner lining having a continuous longitudinal slot is shrink fitted onto the inner wall surface of the heated tube bend, and subsequently the tube or respectively the tube bend is cooled.
7. A method as defined in claim 5 wherein the tube or respectively the tube bend is heated, then an inner lining having a continuous longitudinal slot is shrink fitted onto the inner wall surface of the heated tube bend, and subsequently the tube or respectively the tube bend is cooled and flame hardened in the region of the inner and/or outer circumference tube bend portions.
8. An apparatus for continuously surface hardening the inner surface of tube bends of a constant radius of curvature by means of flame hardening, with or without modifying the core properties of the material, said apparatus comprising a support frame, a shaft horizontally journalled in the support frame, driving motor operatively coupled to the shaft, at least one mounting bracket assembly mounted on the shaft and extending in a direction perpendicular thereof, the mounting bracket assembly including means for fastening a tube bend at its one end, the free end of the mounting bracket assembly defining a circular path during rotary movement of the shaft, a stationary mounting bracket connected at one end to the support frame and mounting at its opposite end a flame hardening burner, the flame hardening burner adapted to be received within the internal cavity of the tube bend, the stationary mounting bracket adapted to include the supply lines leading to the flame hardening burner and being of an arcuate configuration of a radius corresponding to the radius of the circular path described by the tube bend during its movement.
9. An apparatus as defined in claim 8 wherein the mounting bracket assembly for mounting a tube bend includes a guide sleeve whereby the radial extension of the mounting bracket assembly is adjustable so as to adapt the same to the radius of curvature of the tube bend.
10. An apparatus as defined in claim 9 wherein the mounting bracket assembly for a tube bend includes an angle of substantially 70° with a horizontal line in the plane of the circular path.
11. An apparatus for flame hardening a 90° tube bend as defined in claim 8, 9 or 10 wherein the arcuate mounting bracket for the flame hardening burner extends through an arc of about 120°.
12. An apparatus as defined in claim 8, 9 or 10, wherein the flame hardening burner is releasably connected to the mounting bracket and may be replaced by a flame hardening burner of a different outer radius.
13. An apparatus as defined in claim 8, 9 or 10 wherein the flame hardening burner includes a plurality of flame orifices radially spaced about the circumference of the burner.
14. An apparatus as defined in claim 8, 9 or 10 wherein the mounting bracket assembly for a tube bend furthermore mounts a cooling-water pipe in the vicinity of the inner circumferential tube bend portion, the cooling-water pipe including a plurality of cooling-water discharge nozzles directed towards the inner arc tube bend surface.
15. An apparatus for continuously surface hardening the inner surface of tube bends of a constant radius of curvature by means of flame hardening, with or without modifying the core properties of the material, said apparatus comprising a support frame, a shaft journalled in the support frame and adapted to be rotated by a driving motor, a mounting rod is mounted on the shaft and extends in a direction perpendicular thereto, a mount-ing bracket is connected to the free end of the mounting rod, the flame hardening burner is connected to the free end of the mounting bracket, the mounting bracket being adapted to include the supply lines for the flame hardening burner, and a stationary mounting arm for attachment of a tube bend is connected to the support frame.
16. An apparatus as defined in claim 8 wherein the longitudinal extension of the flame hardening burner substantially corresponds to the longitudinal extension of a tube bend, and cooling means is disposed at the downstream end of the flame hardening burner facing away from the direction of circular move-ment, the longitudinal extension of the cooling means substantially corresponding to the longitudinal extension of a tube bend.
17. An apparatus as defined in claim 16, wherein the flame hardening burner and the cooling means are both arcuately curved, with a radius substantially corresponding to the radius of curvature of a tube bend, the flame hardening burner and the cooling means being connected at one end to the free end of a mounting rod, the mounting rod being secured perpendicularly to one end of a shaft, the shaft being journalled in a support frame and adapted to be rotated by a driving motor, the other end of the mounting rod being connected to the free end of the cool-ing means, and a stationary mounting arm is connected to the support frame and adapted to mount the tube bend.
18. An apparatus as defined in claim 8, wherein the flame hardening burner comprises a plurality of discrete arcuate burner segments arranged in a substantial-ly circular configuration, a first group of the burner segments being mounted on a first arcuate mounting arm, a second group of the burner segments being mounted on a second arcuate mounting arm, first and second arcuate mounting arms being of substantially equal lengths and of a substantially semicircular configuration and adapted to be adjusted to the inner diameter of tube bends being treated, a central mounting hub mounting another arcuate burner segment disposed intermediate said first and second group of burner segments, the first and second mounting arms at their one opposing ends being pivotably mounted on said intermediate burner element, and at their other opposing ends being interconnected by a spacer assembly.
19. An apparatus as defined in claim 18, wherein the individual burner segments are hingedly interconnected and are coupled to the central mounting hub by biasing springs.
20. An apparatus as defined in claim 19, wherein the burner segments are provided with cooling devices.
21. An apparatus defined in claim 20, wherein the burner segments and the cooling devices are connected to corresponding supply lines.
22. An apparatus for continuously surface hardening the inner surface of a tube of a tube bend of constant radius of curvature by means of flame hardening, with or without modifying the core properties of the material, comprising a support frame, a driven shaft journalled in the support frame, first mounting means mounting the tube bend, second mounting means mounting a curved flame hardening burner and supply lines therefor, said burner having a curvature corresponding to that of the tube bend, one of said first and second mounting means being fixedly attached to the support frame and the other of said first and second mounting means being mounted on the shaft, such that on rotation of the shaft there is relative movement between the tube bend and the burner in the same circular path, the burner being received in the internal cavity of the tube bend.
23. A method of continuously surface hardening the inner surface of a tube bend of constant radius of curvature by means of flame hardening, with or without modifying the core properties of the material, wherein relative movement between the tube bend and a curved flame hardening means is provided along the circular path of radius corresponding to the radius of curvature of the tube bend center line, such that the flame hardening means will be disposed in the inner cavity of the tube bend with flames of the flame hardening means impinging on the inner tubular wall surface of the tube bend.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19742445678 DE2445678C2 (en) | 1974-09-25 | 1974-09-25 | Device for surface hardening by local heating of the inner surface layers of pipe bends |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1069418A true CA1069418A (en) | 1980-01-08 |
Family
ID=5926635
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA235,228A Expired CA1069418A (en) | 1974-09-25 | 1975-09-11 | Method and apparatus for flame hardening the inner wall surface of tube bends |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1069418A (en) |
| DE (1) | DE2445678C2 (en) |
| FR (1) | FR2286196A1 (en) |
| IT (1) | IT1047421B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4257831A (en) * | 1978-06-12 | 1981-03-24 | Vinzenz Siller | Process for the continuous hardening of pump casings |
| US4298189A (en) * | 1978-06-12 | 1981-11-03 | Vinzenz Siller | Apparatus for the continuous hardening of pump casings |
| CN106222365A (en) * | 2016-08-22 | 2016-12-14 | 江苏捷凯电力器材有限公司 | A kind of Wear-resistant Treatment technique improving transmission line hardware |
-
1974
- 1974-09-25 DE DE19742445678 patent/DE2445678C2/en not_active Expired
-
1975
- 1975-09-11 CA CA235,228A patent/CA1069418A/en not_active Expired
- 1975-09-16 FR FR7528414A patent/FR2286196A1/en active Granted
- 1975-09-19 IT IT6934475A patent/IT1047421B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| DE2445678C2 (en) | 1984-05-17 |
| IT1047421B (en) | 1980-09-10 |
| FR2286196B3 (en) | 1978-05-05 |
| DE2445678A1 (en) | 1976-04-08 |
| FR2286196A1 (en) | 1976-04-23 |
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