FR2513921A1 - METHOD FOR ASSEMBLING METAL PIPES BY EXPLOSION AND DEVICE FOR IMPLEMENTING SAID METHOD - Google Patents

Abstract

PROCEDURE FOR ASSEMBLING BY EXPLOSION PIPES 1, 2, FOLLOWING WHICH AN EXTERNAL RING 3 IS PLACED ON THE JOINT BETWEEN THE PIPES AND AN INTERNAL RING 8 HAVING A V-SHAPED EXTERNAL SURFACE IS PLACED ON THE INSIDE OF THE FACE PIPES A THE OUTER RING. THE EXPLOSION OF AN EXPLOSIVE ANNULAR CHARGE 16 ARRANGED INSIDE THE INTERNAL RING 8 CAUSED BY DETONATORS 17 REGULARLY DISTRIBUTED AROUND THE CIRCUMFERENCE OF THE CHARGE IN THE RADIAL CENTRAL PLANE OF THIS RING, CAUSES THE EXPANSION OF THE RING INTERNAL 8 DEFORMING THE ENDS OF THE PIPES 1, 2 AT THE SAME TIME THAT THE MATERIAL OF THE INTERNAL RING IS WELDED TO THE MATERIAL OF THE ENDS OF THE PIPES. THIS ASSEMBLY PROCESS ADVANTAGEOUSLY REPLACES THE CLASSIC PROCESS BY WELDING METAL PIPES, ESPECIALLY FOR PIPELINES AND URBAN HEATING PIPES.

Description

The present invention relates to a

  explosion pipe assembly method according to

  which one introduces the ends vis-à-vis the

  yaux between an outer metal ring and an inner metal ring, the latter having an outer profile having inclined edges, so that a wedge-shaped gap is formed between the ring

  inside and the inner side surface of the

  of each of the pipes, after which it provokes the ex-

  explosion of an explosive charge inside the

interior.

  We already know various assembly processes

  For example, the British patent

  No. 766,741 describes a process according to which

  the ends of the pipes between an outer ring

  re and an inner ring, and then explodes an explosive shaped like a cylinder inside the latter The ends of the pipes and the ring

  are therefore deformed in such a way as to

  thus blending a shape-dependent seal between

  The inner ring, which is made of

  Such a lead, such as lead, is forced into the gap between the end surfaces of the pipes to protect these end surfaces against corrosion. When using this method, there is a significant risk that the seal will not be sealed. vis-à-vis the media

  high pressure and at a high temperature

  mechanical strength of the seal is almost totally dependent on the deformation of the outer ring

  and ends of the pipes, since the

  interior is made of a soft material which

  does not increase the resistance appreciably.

  U.S. Patent No. 3,290,771 discloses an explosive assembly method of thin-walled pipes with a corrosion protection coating. The ends of the pipes are introduced into annular grooves or depressions formed in the ends of a sleeve. plastic,

  surrounding the explosive charge and is in turn

  turned by a separable outer ring provided with a

  pair of annular grooves As a result of the explo-

  The grooves give rise to alternating ribs and troughs in the ends of the pipes and the sleeve which locks the ends of the pipes to the sleeve. After the explosion, the outer ring is split and removed. This method can not be used. to join thin pipes and not to join heavy iron pipes, for example in oil and gas pipelines and, in particular,

  to join district heating pipes which must

  can withstand pressures up to 20 bar and temperatures up to 1200 C.

  In general, the present invention

  The purpose of this invention is to provide a method for explosively producing a high-strength gasket mainly between heavy metal pipes, such as pipeline pipes and district heating pipes. Up to now, such pipes have been welded between them, which is an expensive process

  which requires a high level of professional qualification

  particularly as work

  welding should often be carried out in

  inaccessible, such as within the confines of

  In many cases, welded joints

  to be X-rayed, further increasing costs.

  Thus, the object of the invention is also to propose a simpler method, which takes less time and

  which requires less important equipment to join

  pipes, especially pipes that are

  located in positions of difficult access.

  This result is obtained in accordance with the

  vention using an annular explosive charge

  exploded by means of detonation

  which produce a regularly distributed explosion

  around the circumference of the load, in the central radial plane of the load, so as to produce explosive waves directed in opposite directions to

  from the central plane of the charge, the explosive force

  the load being adapted so that the collision pressure between the ends of the pipes

  and the inner ring, when the latter rises

  git, produces a weld between the material of the ring

  inside and the material of the ends of the pipes.

  The invention is based on the idea of creating conditions similar to those which exist in the explosion welding of two sheets, for example, according to which a sheet, after a short acceleration distance, is caused to strike another sheet. ,

  the explosion being triggered at one end of such

  so that the collision occurs gradually

  towards the other end Using,

  according to the invention, an inner ring having inclined edges and triggering the explosion in the center, the collision zones start from the center in opposite directions towards the ends of the

the inner ring.

  Pipe assembly in locations

  inaccessible is particularly simple, if

  to a preferred application of the process of the in-

  vention, the inner ring is first attached to the outer ring by means of spacing means centrally placed between the edges of the rings.

  then slide the outer ring with the

  inside of the end of a first pipe, until the edge of the end

  of the pipe comes into abutment against the space means-

  located in the gap between the rings After attaching the annular explosive charge in place on

  the inside of the inner ring, we introduce the

  the end of the other pipe in the gap between the rings until its end edge comes into abutment against the spacing means This process requires absolutely no access to the joint properly

  says: it suffices, on the contrary, simply that the

  outside of one of the pipes is accessible from

  how to apply force to this ex-

  tremity to push the pipes against each other.

  The spacing means ensures that the rings are centered precisely relative to the ends

  pipes, which is essential for achieving a

  uniform formation and welding of pipe ends. Other features and benefits of

  the invention will emerge from the description which follows

  given by way of non-restrictive example and in

  the attached drawings in which:

  Fig 1 shows a sectional view

  of an embodiment of a device

  coupling used for the implementation of the

  transferred from the invention applied to a pair of tube ends; Fig 2 shows a variant of the inner ring of Fig 1; Figures 3 and 4 are views, in longitudinal section, of other embodiments of the outer ring and the inner ring before and after the explosion; and Fig. 5 is a side view of a mode of

  performing a spacer element.

  In FIG. 1, the references 1 and 2

  end sections of two standard 32 cm diameter iron pipes, on which

  a coupling device according to the invention is

  This device comprises an outer ring 3

251392 1

  made of iron whose thickness is greater than that of

  yaux and which, therefore, presents a greater

  resistance that the pipes in the radial direction.

  The ring 3 is provided with a peripheral radial groove 4 which is essentially V-shaped and has edges 5, 6 inclined towards each other on either side of a narrow flat bottom surface 8 As

  we can see it in the figure, the extremities of the

  1, 2 extend to the edges of the surface of

background 7.

  Inside the pipes and in the center of the groove 4, is mounted an inner ring 8 of iron whose width is approximately equal to that of

  groove 4 The upper face of this ring

  inclined surfaces 9, 10 which have the same inclination

  than the edges 5, 6 of groove 4.

  these 9, 10 are separated by a groove 11 shallow

  flat-bottomed whose width is equal to the width

from the bottom surface 7.

  The ring 3 and the ring 8 are fixed to each other by means of spacing means which may consist of a corrugated steel strip 12 which has been shown in more detail in FIG. strip 12 comprises alternating portions 13 and 14 which, in the position of the rings shown in FIG. 1, are respectively spot-welded to the bottom of the groove 4 and mounted by snap-fastening in the groove 11 of the ring 8.

  thus has an elasticity that allows elastic movement

  that corresponds to the depth of the groove 11.

  In FIG. 5, the reference 15 designates the welding points at the groove 4 Alternatively, the band 12 can be divided into evenly spaced short segments, as indicated by the dashed lines on the

  Fig 5 Using an elastic band, which closes

  abruptly in the groove of the inner ring,

  the assembly is simple because the inclined surfaces

  9, 10 are used to exclude

  the band An additional benefit that

  result of the use of spacing means of the type de-

  crit is that after deformation, they occupy only one

  very small space, as will be described below.

  In FIG. 1, the upper half represents the position and the shape of the constituent elements of the seal before the explosion of an explosive charge 16 (shown schematically) attached to the inner ring 8. The explosive charge which can be constituted by a charge of annular dynamite, enclosed in a

  paper case by means of a number of detonations

  7 regularly distributed around the circu-

  the load, and connected to electrical wires (18) coming out of one of the pipes. After the explosion and the resulting expansion of the ring 8, we obtain

  a seal that has the appearance shown on the lower half

  The ends of the pipes are

  cone outwards and squeezed between the

  This produces a seal whose tensile strength is fully comparable to that of the pipes themselves. An appropriate dosage of the explosive charge.

  related to careful cleaning of the surfaces of the

  is also the achievement of a weld between

  of the inner ring and the material of the pipes in the region between the arrows of FIG. 1 so as to form a tight seal.

  folds easily into the space between the ex-

  pipes and thus does not impede the process

  As can be seen in Fig 1, the inner ring 8 forms a substantially smooth transition between the ends of the pipes, so that the seal produces no appreciable turbulence in the

flowing medium.

  In the embodiment shown on

Z 513921

  1, the greatest length of the lever arm is obtained during the initial deformation of the pipes, since the inner ring 8 abuts against the ends of the pipes in the vicinity of their outer edges Since the power of the charge depends first of all, the deformation work that must be performed, this arrangement minimizes the required power of the load The medium enclosed in the groove 4 can be quickly discharged through ventilation holes 19 which are regularly distributed

  around the outer ring 3 and which link the reason

  the atmosphere, which also helps to keep the optimum power at low

of the charge.

  The optimal shape of the groove 4 of the outer ring and the inner ring may vary depending on various factors, such as the size

  pipes, the characteristics of the materials, the requirements

  welding, etc. Figs 2, 3 and 4 represent

  various embodiments of the outer ring

  the inner ring and the inner ring

  correspondents have been designated by the same references

these numerals as in Fig 1.

Claims (6)

CLAIMS -   1. Process for assembling pipes by ex-   plosion according to which the ends are introduced   to the pipes (1, 2) between a metal ring   outside (3) and an inner metal ring (8), the latter having an internal profile comprising   both inclined edges (9, 10), so that a   wedge-shaped valle is formed in between the inner-ring   and the inner side surface of the end   each pipe, after which the   plosion of an explosive charge (16) inside the inner ring, characterized in that an annular explosive charge (16) is used which is caused to explode by means of detonator means (17) which produce an explosion regularly distributed around the circumference of the load, in the central plane   of the charge, so as to produce   plosives directed in opposite directions from the central plane of the load, the explosive force of the load being adapted so that the collision pressure, between the ends of the pipes (1,2) and the inner ring (8) when the latter widens,   produces a weld between the ring material   (8) and the material of the ends of the pipes 1, 2).   The process according to claim 1, wherein   characterized in that the inner ring is first fixed   (8) to the outer ring (3) with the help of   spacing yens (12) placed centrally between   edges of the rings (3,8), in that   connect the outer ring to the end of a pipe (1 or 2) until the end edge of the pipe abuts against the spacing means in the gap between the rings (3.8 ), and in   after having fixed in place the explosive charge   (16) on the inside of the inner ring, is introduced in place the end of the other pipe (2 or 1) in the gap between the rings until its end edge comes into abutment against the means   spacing (12) after which the   explosion of the explosive charge (16). 3. Device for assembling metal pipes by implementing the method according to claim 1, which comprises, on the one hand, a ring   outer metal (3) and an inner metal ring   (8) between which the extremities vis-à-vis   pipes (1, 2) can be introduced, the metal ring   inner section (8) having an outer profile   having inclined edges (9,10) and, on the other hand, an explosive charge (16), characterized in that the explosive charge (16) is annular and is provided with detonator means (17) arranged to produce an explosion regularly distributed around   the circumference of the load, in the central plane   of the load, and in that the explosive force of the load (16) is adapted so that the collision pressure between the ends of the pipes (1, 2) and   the inner ring (8), when it departs, pro-   creates a weld between the material of the inner ring   (8) and the material of the ends of the pipes (1,2).   4 Device according to claim 3,   characterized in that the outer ring (3) and the outer ring   interior (8) are fixed to each other by means of spacing means (12) centrally positioned between the inclined edges (9,10) of the inner ring, and that the annular explosive charge (16) is fixed   inside the inner ring (8).   5. Device according to claim 4,   characterized in that the spacing means is   formed by resilient members (12) extending radially inward from the center of the inner side surface of the outer ring and are evenly distributed around the circumference, these members penetrating into a peripheral groove (11) formed in the outer lateral surface of the inner ring (8).   6. Device according to claim 5,   characterized in that the elastic members are formed by one or more corrugated steel strips (12) fixed by welding to the outer ring (3) and snap-fitted in the groove (11) of the inner ring (8).