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Title:
METHOD FOR CALIBRATING THE DIMENSIONS OF A T-BRANCH PIPE AND DEVICE FOR IMPLEMENTING THE METHOD
Document Type and Number:
WIPO Patent Application WO/2022/152963
Kind Code:
A1
Abstract:
The invention relates to a method and device for calibrating the dimensions of a T-branch pipe (1). The T- branch pipe comprises a standard pipe (2) and a collar (3) forming a branch opening, the collar diameter of which is made larger than the desired final size in the longitudinal direction (x) of the standard pipe (2) and smaller than the desired final size in the transverse direction. The collar (3) is flared out by means of a first calibration force (FI) in one direction which is transverse to the longitudinal direction (x) of the standard pipe (2). The standard pipe (2) is flared out locally by means of a second calibration force (F2) and a third calibration force (F3) in two directions. The said flaring out is carried out in stages in such a way that all three calibration forces (FI, F2 ja F3) eventually act simultaneously. When the calibration forces (FI, F2 and F3) act, the standard pipe (2) is reduced in the vicinity of its ends by means of a fourth force (F4) which acts in parallel with the axial direction (y) of the collar (3).

Inventors:
LARIKKA LEO (FI)
Application Number:
PCT/FI2021/050895
Publication Date:
July 21, 2022
Filing Date:
December 20, 2021
Export Citation:
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Assignee:
LARIKKA LEO (FI)
International Classes:
B21C37/29; B21D31/00; B21D37/06; F16L41/04
Foreign References:
AU2003200324A12003-08-21
US4307593A1981-12-29
Attorney, Agent or Firm:
LEITZINGER OY (FI)
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Claims:
Claims

1. A method for calibrating the dimensions of a T-branch pipe (1), the T-branch pipe comprising a standard pipe (2) and a collar (3) forming the branch opening, the collar diameter of which is made larger than the desired final size in the longitudinal direction (x) of the standard pipe (2) and smaller than the desired final size in the transverse direction, characterised in that the collar (3) is flared out by means of a first calibration force (Fl) in one direction, which is transverse to the longitudinal direction (x) of the standard pipe (2), that the standard pipe (2) is flared out locally by means of a second calibration force (F2) and a third calibration force (F3) in two directions, and that the said flaring out is carried out in stages in such a way that all three calibration forces (Fl, F2 and F3) eventually act simultaneously.

2. A method according to claim 1, characterised in that when the calibration forces (Fl, F2 and F3) act, the standard pipe (2) is reduced in the vicinity of its ends by a force (F4) which acts in parallel with the axial direction (y) of the collar (3).

3. A method according to claim 1 or 2, characterised in that the calibration mandrel (11) of the standard pipe (2) is inserted in the standard pipe (2), the calibration mandrel (4) of the collar (3) is lowered through the collar (3) against the calibration mandrel (11) of the standard pipe (2), the calibration mandrel (4) of the collar (3) is extended in a direction transverse to the direction of the longitudinal axis (x) of the standard pipe (2) to flare out the collar (3) in a corresponding direction, the calibration mandrel (11) of the standard pipe (2) is extended in the axial direction (y) of the collar (3) to flare out the standard pipe (2) in a corresponding direction next to the collar (3), the calibration mandrel (11) of the standard pipe (2) is extended in a direction transverse to the axial direction (y) of the collar (3) to flare out the standard pipe (2) in a corresponding direction.

4. A device for calibrating the dimensions of a T-branch pipe (1), the T-branch pipe (1) comprising a standard pipe (2) and a collar (3) forming the branch opening, the collar diameter of which is larger than the desired final size in the longitudinal direction (x) of the standard pipe and smaller than the desired final size in the transverse direction, characterised in that the device comprises a collar (3) calibration mandrel (4) including first calibration members (5, 6), by means of which a first calibration force (Fl) can be exerted on the collar (3) in a direction transverse to the longitudinal direction (x) of the standard pipe (2) to flare out the collar in the corresponding direction, a standard pipe (2) calibration mandrel (11) including second calibration members (18), by means of which a second calibration force (F2) can be exerted on the standard pipe (2) next to the collar (3) in the axial direction (y) of the collar (3) to flare out the standard pipe (2) and third calibration members (20), by means of which a third calibration force (F3) can be exerted on the standard pipe (2) in a direction transverse to the axial direction (y) of the collar (3) to flare out the standard pipe (2), and that the said flaring out can be carried out in stages in such a way that all three calibration forces (Fl, F2, F3) eventually act simultaneously.

5. A device according to claim 4, characterised in that the device comprises plungers (31) fitted in connection with both ends of the standard pipe (2) by means of which the standard pipe (2) can be reduced in the vicinity of its ends, by a force (F4) acting parallel with the axial direction (y) of the collar (3), while the calibration forces (Fl, F2, F3) act simultaneously.

6. A device according to claim 4 or 5, characterised in that the calibration mandrel (11) of the standard pipe (2) can be inserted in the standard pipe (2) and the calibration mandrel (4) of the collar (3) can be brought through the collar (3) against the calibration mandrel (11) of the standard pipe (2).

Description:
Method for calibrating the dimensions of a T-branch pipe and device for implementing the method

The present invention relates to a method for calibrating the dimensions of a T- branch pipe, the T-branch pipe comprising a standard pipe and a collar forming the branch opening, the collar diameter of which is made larger than the desired final size in the longitudinal direction of the pipe and smaller than the desired final size in the transverse direction.

The present invention further relates to a device for implementing the method for calibrating the dimensions of a T-branch pipe, the T-branch pipe comprising a standard pipe and a collar forming the branch opening, the diameter of the collar being larger than the desired final size in the longitudinal direction of the pipe and smaller than the desired final size in the transverse direction.

In such T-branch pipes, in which a branching cylindrical collar is made in a tubular casing by stretching the material, the elasticity of the pipe and the internal stresses created in the material have an adverse effect on the shape and dimensions of the collar formed and the standard pipe. Especially when the dimensions of the standard pipe and collar diameter are large with respect to the wall thickness, for example over 70 mm, dimensional errors and defects of form are common. An attempt has been made to partly eliminate the adverse effects that occur during the collar forming stage, for example, in the patent publication EP 1332807 Bl, wherein a calibration tool is used with the aim of only affecting the dimensions of the collar.

In reality, defects of form or deformations occur at the collar forming stage also in the standard pipe. Such deformations are shown in an exaggerated manner and by way of an example in the accompanying Fig. 1. The outlines of a finished, calibrated T-branch pipe 1 are shown in broken lines marked with reference numerals 2' and 3'. After the formation of the collar 3, the dimension of the collar 3 itself is larger in the longitudinal direction of the standard pipe than in the direction transverse to the longitudinal direction of the standard pipe. The stress created by the collar 3 in the standard pipe 2 is so great that the standard pipe 2 buckles next to the collar 3 in the longitudinal direction of the pipe on both sides of the collar, whereupon the ends of the standard pipe rise upwards in the radial direction of the standard pipe at the buckling. The mouths of the standard pipe are then substantially egg-shaped.

The object of the present invention is to substantially eliminate the above-mentioned problems arising from the formation of the collar.

To achieve the foregoing object, the method according to the present invention is characterised in that the collar is flared out by means of a first calibration force in one direction, which is transverse to the longitudinal direction of the standard pipe, that the standard pipe is flared out locally by means of a second and third calibration force in two directions, and that the said flaring out is carried out in stages in such a way that all three calibration forces eventually act simultaneously.

Furthermore, the device for implementing the method according to the invention is characterised in that the device comprises a collar calibration mandrel including first calibration members, by means of which a first calibration force can be exerted on the collar in a direction transverse to the longitudinal direction of the pipe for flaring out the collar in the corresponding direction, a standard pipe calibration mandrel including second calibration members, by means of which a second calibration force can be exerted on the standard pipe next to the collar in the axial direction of the collar for flaring out the standard pipe and third calibration members, by means of which a third calibration force can be exerted on the standard pipe in a direction transverse to the longitudinal direction of the standard pipe for flaring out the standard pipe, and that the said flaring out can be carried out in stages in such a way that all three calibration forces eventually act simultaneously.

Preferred embodiments of the present invention are disclosed in the dependent claims.

The present invention is described in greater detail in the following, with reference to drawings according to a preferred embodiment of the invention, of which:

Figure 1 shows defects of form in the T-branch pipe as exaggerated views from different directions, Figure 2 shows a cross-section of the T-branch pipe with the calibration mandrels of the standard pipe and the collar in the starting position for calibration,

Figure 3A shows the cross-section according to Figure 2 when the collar calibration mandrel is lowered against the standard pipe calibration mandrel for calibrating the collar with the first calibration member,

Figure 3B shows the arrangement according to Figure 3A as a longitudinal section of the T-branch pipe,

Figure 4 shows the arrangement according to Figure 3B when the second calibration members of the calibration mandrel of the standard pipe are in operation,

Figure 5A shows a cross-section of the arrangement according to Figure 4 when the third calibration members of the calibration mandrel of the standard pipe are in operation,

Figure 5B shows a partial enlargement of section IVA in Figure 5A,

Figure 6 shows an actuator to be positioned inside the calibration mandrel of the standard pipe for moving the second and third calibration members, and

Figure 7 shows a side view of the arrangement according to Figure 5B when the end plungers are in operation.

Figure 1 thus shows top, side and end views of the T-branch pipe marked with reference numeral 1. In the T-branch pipe shown in Fig. 1 has been made a collar 3 which is formed of the edges of a hole made in the standard pipe 2, but which has not yet been calibrated according to the invention. Thus, in Fig. 1 can be seen the deformations resulting from the formation of the collar 3 which were already specified above. It should also be mentioned that the deformations shown in Fig. 1 are exaggerated in order to better present the inventive idea. It should further be mentioned that the diameter of the collar is at this stage made larger than the desired final size in the direction of the longitudinal axis x of the standard pipe 2 and smaller than the desired final size in the transverse direction of longitudinal axis x. The longitudinal oversize is intentional and the transverse undersize is an unavoidable result of the operating principle of the collaring device.

Figures 2, 3A and 3B show a device for implementing the present invention. Fig. 2A shows a cross-section of a T-branch pipe 1 supported on a support element 24. The collar 3 of the T-branch pipe 1 is preferably oriented so that its longitudinal axis y is substantially vertical (at a 90° inverted angle with respect to the longitudinal axis x of the standard pipe 2) and the mouth opens upwards. The device comprises an elongated calibration mandrel 11 fitted in the space limited by the standard pipe 2. The calibration mandrel 11 of the standard pipe is inserted in the standard pipe 2 in the direction of the longitudinal axis x transverse to y-axis. The calibration mandrel 11 has a substantially circular cross-section and a slightly smaller diameter than the standard pipe 2. On the calibration mandrel 11, over a part of its longitudinal distance, are formed surfaces 12 and 13 which are bevelled with respect to the plane passing through the y-axis, the surfaces being formed, for example, by milling on the surface of the calibration mandrel 11. The surfaces 12 and 13 are formed in the upper part of the calibration mandrel. The calibration mandrel 11 is positioned in the direction of longitudinal axis x in such a way that the bevelled surfaces 12 and 13 are at the opening of the collar 3. The rest of the structure and operation of the calibration mandrel 11 are described in greater detail below.

Figures 2 and 3A show the collar 3 calibration mandrel 4 which is formed, over a part of its distance in the direction of the y-axis, to be such that it can be brought, in the direction of arrows A shown in Fig. 2, by transfer means 10, in the manner shown in Fig. 3A, in connection with the calibration mandrel 11 inserted in the standard pipe 2 through the collar 3 opening. Figure 3B shows a side view of the situation according to Fig. 3A. The collar calibration mandrel 4 mainly consists of two halves 5 and 6, which are arranged to move a distance with respect to each other in a direction transverse to longitudinal axis x. For moving, the transfer means 10 in the upper part of the mandrel 4 is equipped with an arm 9a, 9b provided with a joint 10a. While the mandrel 4 is taken into position, a part of the thrust of the transfer means 10 is exerted on the joint 10a, whereupon parts 9a and 9b of the arm turn in the same direction (Fig. 3A, arrows C). This in turn causes the two halves 5 and 6 of the mandrel 4 to move away from each other, at the same time expanding the calibration mandrel 4 in a direction transverse to longitudinal axis x. In both halves 5 and 6 are formed gripping projections 7 and 8, in which are formed mating surfaces that are positioned against the bevelled surfaces 12 and 13 of the calibration mandrel 11 of the standard pipe 2 while the mandrel 4 is put in place. On the surface of the mandrel 11 are in addition formed spaces 14 and 15 in which the gripping projections 7 and 8 can be fitted. When the gripping projections 7 and 8 impact with the calibration mandrel 11, the gripping projections 7 and 8 are pressed against the body of the calibration mandrel 11 under force B. In connection with spaces 14 and 15 can be placed so-called wearing blocks 16 and 17. Their purpose is to receive the gripping projections 7 and 8 of the mandrel 4 which would otherwise rub against the bevelled surfaces 12 and 13 formed when the mandrels 4 and 11 move with respect to each other and the mandrel 4 halves 5 and 6 move away from each other, generating forces Fl. The wearing blocks are easy to replace when necessary.

The cross-section of the mandrel 4 is dimensioned in such a way that the mandrel 4 can be brought through the collar 3 opening into the position shown in Figs. 3A and 3B. On the mandrel 4 halves 5 and 6 are provided outer surfaces, which first move in a direction transverse to the longitudinal axis x against the inner surface of the collar 3, that is, especially from the part of the collar where the diameter of the collar is smaller than the desired final size. Secondly, when the halves 5 and 6 move away from each other, these surfaces exert forces Fl on the above-mentioned inner surfaces of the collar. Under forces Fl, the smaller than desired collar diameter section of the collar 3 spreads, "stretches", to the desired collar diameter size. At the same time, the internal stress of the collar 3 changes. Due to this, the opposite collar diameter sections of the collar, which are larger than desired, tend to neck towards each other, whereupon the surface of the mandrel 4 receives the collar at the corresponding sections. Finally, the mandrel 4 exerts counterforces F1A (see Fig. 3B) and stops the necking movement. The cross-section of the mandrel 4 is such that the sections of the collar diameter which were originally made larger than desired maintain the desired collar diameter size. In this way, the diameter of the collar 3 can be rendered substantially round over its entire distance. In the following is described the structure and operation of the calibration mandrel 11 of the standard pipe 2 with reference to Figs. 4, 5a, 5B and 6. In the calibration mandrel 11 with a round cross-section is formed a through hole 11a coaxial to its longitudinal axis x. In the calibration mandrel 11, between its outer surface and the inner surface of the through hole 11a, are formed first bores 19 parallel with the longitudinal axis y of the collar, the bores being located on both sides of the collar 3 in the direction of the longitudinal axis x of the standard pipe 2.

Figure 6 in turn shows an elongated pipe 25, the outer diameter of which corresponds to the inner diameter of the through hole 11a of the calibration mandrel. On the outer surface 26 of the pipe 25 are formed two wedge surface pairs 27a, 27b located at a distance from each other in the longitudinal direction of the pipe. The wedge surfaces of the wedge surface pair 27a, 27b are located on opposite sides of the outer surface of the pipe 25. The direction of ascent of each wedge surface is perpendicular to the direction of the longitudinal axis of the pipe.

Inside the pipe 25 is coaxially arranged, preferably with a sliding fitting, a bar 29 which is in its longitudinal direction a distance longer than the pipe 25. On the surface of the bar 29 are formed two wedge surfaces 30 at a distance from each other in the longitudinal direction of the pipe. These wedge surfaces 30 are located in the direction of the circumference around the longitudinal axis between the opposite wedge surfaces 27a and 27b of the pipe 25 (in which case the wedge surfaces 27a, 27b are at a 90-degree inverted angle to the wedge surface 30) and in the direction of longitudinal axis x in the vicinity of the wedge surfaces 27a and 27b. The distance between the wedge surfaces 30 is, however, somewhat shorter than the distance between the wedge surface pairs 27a and 27b in the direction of the axis x. In pipe 25 are formed openings 28 in order to provide an operational connection for the wedge surfaces formed in the bar 29 with the other actuators of the calibration mandrel 11.

The pipe 25 and the bar 29, which move with respect to each other, have been inserted in the through hole 11a as shown in Fig. 5A in such a way that the wedge surfaces 30 formed in the bar 29 are in connection with the first bores 19 of the mandrel 11 through a longitudinal opening 28 made in the pipe 25. In each of the first bores is located a lifting pin 22 (see especially Figs. 3B and 4). The lower end of the lifting pin 22 is in contact with the bevelled surface 30 of the bar 29 located in the through hole 11a. In connection with the upper end of the lifting pin 22, with the upper end extending in the radial direction of the mandrel 11 close to the outer surface of the mandrel 11, is arranged a flat support element 18. The support element 18 is thus located between the outer surface of the calibration mandrel 11 and the inner surface of the standard pipe 2. On the running surface of the calibration mandrel 11 are recesses for the support elements 18.

Similarly, the wedge surfaces 27a and 27b formed on the pipe 25 are in connection with the second bores 21 of the mandrel 11 at corresponding points. In each of the second bores 21 is also located a lifting pin 13. The lower end of each lifting pin 13 is contact with the wedge surfaces 27a and 27b of the pipe 25 at corresponding points. In connection with the upper end of each lifting pin 13, with the upper end extending in the radial direction of the mandrel 11 close to the outer surface of the mandrel 11, is arranged a flat support element 20.

According to the embodiment disclosed, the calibration mandrel 11 is extended in the axial direction y of the collar 3 as follows. When the bar 29 is moved in the direction of longitudinal axis x, the lifting pins 22 move due to the effect of the wedge surfaces 30 in a direction transverse to the longitudinal axis (in the direction of the y-axis), lifting the flat support elements against the inner surface of the standard pipe 2, as shown in Fig. 4. For moving the bar 29 can be used separate power units, which are not shown here. The support elements 18 exert a force F2 against the inner surface of the standard pipe 2, adjacent to the collar 3, the force correcting the changes in the standard pipe 2 formed adjacent to the collar 3. The T-branch pipe 1 remains in place because the collar 3 calibration mandrel 4 still presses it against the support element 24 by means of the calibration mandrel 11 of the standard pipe 2. In addition, the plungers 31 act on the standard pipe 2 from the outside by force F4, to which force F2 forms a counter support, as described below with reference to Fig. 7.

After this, the calibration mandrel 11 is extended in a direction transverse to the direction of the longitudinal axis x of the standard pipe 2 by moving the pipe 25 around the bar 29 with separate power units (not shown) in a corresponding manner as the bar 29 was moved in the direction of longitudinal axis x. The lifting pins 23 then move, by the effect of the rising wedge surfaces 27a and 27 b (Fig. 6), with respect to the y-axis (thus also with respect to the longitudinal axis x) in a transverse direction, moving the flat support elements 20 against the inner surface of the standard pipe 2 as shown in Fig. 5A and especially in Fig. 5B. The support elements 20 exert forces F3 against the inner surface of the standard pipe 2, the forces acting in the circumferential direction of the standard pipe 2 at a 90-degree inverted angle with respect to forces F2 and on both sides of forces F2. Forces F3 correct the deformations formed in the standard pipe 2 which are in the circumferential direction of the standard pipe 2 substantially transverse with respect to the deformations corrected by forces F2. In the direction of the x-axis, forces F2 are closer to the collar than forces F3, which are close to the ends of standard pipe 2. This has been achieved through the positioning of pins 22 and 23 in such a way that pins 22 lift the inner ends of the support elements 18 and pins 23 lift the outer ends of the support elements 20. In this way, the calibration forces can be exerted on the correct points.

Figure 7 further shows plungers 31 arranged in connection with both ends of the standard pipe 2, by means of which a force F4, which is substantially parallel to the y- axis, is exerted on the ends of the standard pipe. Under force F4, the standard pipe 2 is reduced from the ends to its original size, whereupon the cross-section of the pipe 2 becomes substantially round.

The support elements 18 and force F2 form a point of support for force F4 created by the plungers 31 while force F4 acts. The plungers 31 are designed in such a way that they become positioned over a part of the circumference of the standard pipe 2 and render the part of the pipe into its correct form when force F4 is exerted on it. The above-mentioned forces Fl, Fla, F2, F3 and F4 thus act on the T-branch pipe 1 simultaneously. Each force affects the material of the T-branch pipe 1 in such a way that when the forces are removed, the T-branch pipe maintains the shape into which the forces have "forced" it. In other words, the forces exceed the yield point of the material at the critical points, where the forces act on the T-branch pipe 1. Elastic recovery of the material obviously also takes place which must be taken into account in the dimensioning of the calibration members. The method according to the present invention and the device implementing it are not limited only to the embodiment disclosed but the invention can be applied in several ways within the scope of protection defined in the claims presented.