Note: Descriptions are shown in the official language in which they were submitted.
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The present inven-tion relates to apparatus for axially
ro-ta-tably clamping a cylindrical hollow body during w~ld coating
of -the hollow body to increase t:he wall thickness thereof.
Such apparatus can be used for the production of
cylindrical hollow bodies of large wall thicknesses and con-
siderable lengths (e.g. 10,000 mm), such as are used, for ex-
ample, in reactor construction.
The production of such hollow bodies from high quality
steel has hither-to been limited, since roller devlces, for ob-
vious reasons, cannot handle oversize wall thicknesses, e.g.
~ wall thicknesses of ~00 mm or more.
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It is an object of the present invention to provide a
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novel and improved apparatus for axially rotatably clamping a
cylindrical hollow body.
According to the present invention, there is provided
; apparatus for axially rotatably clamping a cylindrical hollow
body during weld coatiny of the hollow body to increase the wall
thickness thereof, the apparatus comprising first and second
support means for supporting opposite respective ends of the
hollow body; the first and second support means each comprising
a plurality of support members which are radially adjustable
`~1 within the hollow body for releasably clamping the latter; first
and second co-axial cylindrical members on which the first and `
second support means are respectively mounted; and first and
second roller support means for rotatably supporting the first
and second cylindrical members, respectively, and therewith the
first and second support means. `
When the apparatus is in use, a cylindrical hollow
base body of relatively small wall thickness is firstly pre-
fabricated and the wall thickness of this hollow base body, which
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is made of h:Lgh quallty sheet s-teel of small thlckness, is ln-
creased by applyi.ng onto -the periphery thereof a plurality of
helically extending lines of weld material, which are ~used to-
gether.
The roller support means includes respective support
carriages which are relatively displaceable in the axial
' direction o~ the hollow body to accommodate variations in length
~; of the hollow body in response 1;o heating of the hollow body
.~ caused by the melting operation.
Preferably, the ~irst and second support means com-
!'~ prise guide means for slidably guiding the support members
. during their radial adjustment and means are provided for effect-
.~ ing the radial adjustment of the support members to adapt the
apparatus to hollow bodies of different diameters, such means
` comprising, for example, threaded shafts.
~; The roller support means may include wedge means, on
which the rollers are supported, for horizontally and vertically
adjustably displacing the support rollers, and the apparatus
may further comprise drive means for rotating the hollow body,
the drive means comprising a drive motor connected through a
.. i~ thrust bearing to one of the cylindrical members.
It has been found that the weld coating satisfies high
metallurgical requirements for loading capacity, in particular
if the helically extending weld lines are produced on -the axially
rotating base body by a powder welding process.
In order to minimize the production time of a hollow
.~ body produced as described hereinabove, the weld lines may be
` produced by a plurality of horizontally synchronously driveable,
reversible and vertically adjustably arranged welding devices.
For example, the welding devices may comprise welding
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heacls syrlchronously driveable by a chain drive and each associ-
ated with a respective supply carriage.
o compensate for the increasing thickness of the weld
coating, the welding heads may be mounted so as -to be vertically
adjustable.
The supply carriages associated with the welding heads
; serve to receive welding wire provided, for example, on one or
' more reels and welding powder.
In order to ensure that a continuous and therefore
rational working operation can be achieved with respect to the
weld coating, both the welding heads and also ^the supply car-
riages are moun-ted so as to be movable or slidable on rails and
~ transposable. Each supply carriage constitutes, with its associ-
ated welding head, a unit which may, for example, be transposable
` by means of a lifting device, so that the unit, after reaching anP end position, can be returned to an initial position in order to
;~ again take part in the welding process.
:3 For this purpose, the rails may be vertically adjust- -
able, for example by threaded shafts or a hydraulic device, with
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~; 20 respect to the base body.
In order to form the weld coating from a plurality of
helical lines of weld, a drive means, comprising a drive motor
and a thrust bearing, is arranged on a pedestal and cooperates
; with one of the support means. The rotary movement imparted to
; the base body, which is adjusted in accordance with the diameter
of the body and the welding speed, upon simultaneous horizontal -;~
and axial movement of the welding heads produces the helical
weld lines which, fusing ^together, form the weld coating on the
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base body.
The support means may comprise support discs carrying
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the support members, the support discs being in force trans-
mit-ting connec-tion wi-th hollow stub shaf-ts forming the cylin-
drical members, which in turn are each mounted on the above-
; mentioned support carriages~
he arrangement is such -that the driven end of -the
base body serves as a fixed point, while the opposite end of
~; the base body, which likewise lies on one of the support car-
,i riages, can extend axially in response to the heating e~fect
by movement of the carriage which is provided at such other end
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mounted on running rollers so as to be horizontally displaceable.
The invention will be more readily understood from the
following description of a preferred embodiment thereof given,
:`! by way of example, with reference to the accompanying drawings,
in which:-
Figure 1 shows a side view of apparatus for producing
a large diameter cylindrical body; and
Figure 2 shows an end view of parts of the apparatus
'~ of Figure 1.
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~i In Figure 1, there is illustrated a pedestal 1 on
which are mounted a drive motor 2 and a thrust bearing 3. The
thrust bearing 3 is drivingly connected to one of a pair of
hollow stub shafts 6, which are each supported on support rol-
lers 8 of a respective carriage 5, which in turn is mounted on
running wheels.
The hollow shafts 6 extend into opposite ends of a
,~ prefabricated base body 10, which has a circular cross-section
,~ and a relatively thin wall thickness (e.g. 30 to S0 mm), the
hollow shafts 6 each being rotatably supported on the carriages
5 by the support rollers 8, which contact the outer peripheries
of the hollow shafts 6.
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ach of the hollow shaf-ts 6 carrles a support disc 9,
which is provided with guide rails 11 slidably yuiding support
members 7. The support members 7 are radially adjustable by
threaded shaft or worm mechanism or the like (not shown) for
clamping engagement with the interior wall surface of the pre-
fabricated base body 10, which is made of high quality steel.
The support members 7, radially displaced this way into ahutment
~' with the base body 10, ensure that even when the latter is raised
~ to high temperatures by the weldiny operation, it retains its
; 10 circular cross-section. The longitudinal expansion of the hollow
body caused by the welding heat is taken up by corresponding dis-
; placement, on its running wheels, of the carriage 5 which is
located at the end of the hollow body 10 opposite from that which
i is driven by the drive motor 2.
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a A welding device illustrated in Figure 1, and in
particular its control device for the welding units which are
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synchronously driveable in the horizontal direction, through a
chain drive (not sh~wn) is not the subject matter of the present
invention and therefore, for the sake of simplicity, will be
described only with respect to its more important features.
As is apparent, a weld coating 18 applied to the ex-
-terior of the base body 10 is produced by a plurality of welding
heads 19, each of which forms a unit with a respective supply
carriage 21, which holds a large supply of welding wire and
powder. Each unit is mounted for displacement along a common -
track 22 and can be lifted from the latter by means of a lifting ~-
device (not shown) as soon as it reaches an end position, i.e. ~ `
~'~ the vicinity of the left-hand end of the base body 10 as viewed
in Figure 1. ,-
The unit is then returned to its initial position, i.e.
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to the vicinlty of the right-hand end of the base body 10 as
viewed in Figure 1, and then begins the production of a further
helical line oE weld.
To adapt to -the particular base body 10 being pro-
'~` cessed, which may vary in diameter e.g. from 3,000 to 7,000 mm,
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the hollow shafts 6 which support the base body 10 through the
support discs 9 and the support members 7 are moun-ted on the
support rollers 8, whlch are both horizontally and vertically
; adjustable by means of threaded shafts 13 and 14 and a ~air of
10 wedges 15 and 17 supporting the rollers 8.
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Since the spacing of the welding heads from the hollow
body 10 must be increased as the thickness of the weld coating
18 increases, e.g. from 400 to 700 mm, about 50 hours being re-
quired for a diameter increase of 8 to 10 mm, the welding heads
19 must be vertically adjustably mounted.
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`I The diameter of the hollow base body varies from case
to case. This is taken into account by making the rails 22,
which mount the welding heads 19 and the supply carriayes 21,
~ vertically adjustable by threaded adjustment shafts 23.
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