GB2288996A - Pipe connection,and pipe therefore - Google Patents

Abstract

A pipe connection, and a pipe therefore wherein a connecting portion of the pipe had two oppositely facing tensioning faces of conical configuration, a first tensioning face 16 being at least partially received in a conical bore 6 in a connecting member, the bore being of a DIN standard configuration, and the other tensioning face 19 being supported by a conical face 13 in a nut member slidable over the pipe, wherein the connecting portion of the pipe is produced by upsetting the pipe in a two part tool whose parts are moved relative to one another by an upsetting distance in the range 6mm to 8.5mm, and operate on a pre-determined length of pipe calculated by adding lengths dictated by certain DIN standards relating to pipe fillings. <IMAGE>

Description

2288996 PATENTS ACT 1977 -I- Title: PIPE CONNECTION, AND PIPE THEREFOR

Description of Invention

This invention relates to a pipe connection wherein a connecting portion at or adjacent the end of a pipe is provided with two tensioning faces which are of conical configuration and which face in opposite directions, the first tensioning face being at least partially received in a conical bore which is provided in a connecting member and whose configuration is in accordance with the standard (DIN 3861, May 1994 edition) for cutting rings for different outer pipe diameters, and the other tensioning face being supported against a conical face of a nut member slidable over the pipe and cooperating with the connecting member, the conical face in the nut member having a cone angle of substantially 90'. Such a pipe connection will hereafter be referred to as a pipe connection of the kind specified.

The invention further relates to a pipe adapted to be used in such a pipe connection, and to a method of producing a connecting portion of appropriate configuration on the pipe.

A pipe for a pipe connection, having a connecting portion formed out of the material of the pipe and with the configuration of a standardised cutting ring is described in DD-240059A1, but the cone angle of a first tensioning face on the pipe is smaller than the cone angle of the conical bore of the threaded sleeve with which it cooperates in a pipe connection. The intention is to achieve linear contact with the first tensioning face of the pipe at the smallest diameter of the conical bore, in order to increase the sealing effect. A second tensioning face, cooperating with the union nut engaging the threaded sleeve, is pressed on the pipe, and a conical portion starting therefrom and running out towards the end of the pipe is formed onto the pipe together with the first tensioning face. The disadvantage of this embodiment is that high axial tensioning forces result in high pressures on the pipe material, which means that settlement may occur and 2 stringent sealing requirements may not be met permanently. In the case of cyclic bending loads applied to the pipe, the linear of support of the pipe in the sleeve also leads to settlement and thus to leakage.

US-4871199 describes a pipe connection and method of producing the same, wherein a conical bore in a connecting member has a cone angle in the range 30' to 40'. A face of a nut cooperating therewith preferably extends at right angles relative to the longitudinal axis of the nut, but may alternatively be in the form of a shoulder extending at 45' relative to the axis. The connecting portion of the pipe is produced by axially upsetting the same in a multi-part tool, with deformation taking place in such a way that in the region of the connecting portion the pipe is folded. The folds are retained because during subsequent assembly the purpose is further to deform the folds by tightening the nut. Such folds are said to have a resilient compensating effect to ensure that even at high internal pressures the connection remains leak proof.

The disadvantage of such a design is that, as a result of internal pressures and especially when subject to vibration, the connection may be subject to settlement because the resilience of the folds in the pipe is insufficient. Thus the connection begins to leak and has to be retightened.

DIN standard 2352, June 1991 edition, specifies requirements for solderless threaded pipe connections including cutting rings, and determines possible dimensional relationships for several series of different types of connection. The design of the associated union nuts is described in DIN 3870, May 1985 edition, and that of the threaded journals in DIN 3853, November 1982 edition. The associated cutting rings are defined in DIN 3861, May 1994 edition. The union nuts and the connecting members or male fittings with which they engage are designed in such a way that even when the connection has been tightened there remains a certain amount of possible further movement therebetween, to permit re-tightening. In consequence, the axial dimensions of the cutting ring and portions of the pipes with which they engage have to be S 3 greater than are required by the depth of the receiving bore in the connecting member and the union nut.

It is broadly the object of the present invention to provide a pipe connection, pipe and method of producing the latter wherein a leak proof connection is ensured even at high pressures and conditions of vibration, and which, furthermore, can be produced at reasonable cost.

In accordance with one aspect of the present invention, there is provided a pipe for use in a pipe connection of the kind specified, wherein the connecting portion is produced by upsetting the pipe in a tool compris. ing at least two parts movable relative to one another in the direction lengthwise of the pipe axis, by increasing the upsetting force until the two tool parts have moved relative to one another in the direction along the pipe axis by a predetermined upsetting distance, a first tool part comprising a first conical pressing face forming part of a bore and whose shape matches the conical bore in the connecting member, and further comprising a stop face for the end of the pipe; a second tool part comprising a second conical pressing face in the form of a bore and having a cone angle of W; the free pipe length which is to be subjected to the upsetting operation, and which projects from the smallest diameter of the second conical pressing face towards the stop face, corresponding to the length of a sealing cone in accordance with DIN standard 3865, May 1994 edition, which length is equal to the difference between lengths 13 and 1, (as shown in embodiment A, Figure 1 of said standard) plus the length of the conical bore resulting from DIN standard 3861, May 1994 edition, for bore shape W, and optionally plus the length of a projecting pipe portion for reception in, and shorter than, a cylindrical bore portion adjacent the standardised conical bore in the connecting member, and plus the length of the upsetting distance which is in the range 6mm to 8.5mm, the upsetting distance assuming its maximum value towards the greatest outer pipe diameter used.

The invention also provides a pipe connection of the kind specified wherein the pipe is in accordance with the first aspect of the invention and 4 wherein the conical bore in the connecting member extends from an end face thereof and whose smallest diameter is followed by a cylindrical bore portion comprising a bore shape W in accordance with DIN standard 3861, May 1994 edition.

In the invention, it is found that the connecting portion of the pipe is not deformed during an assembly operation or even during repeated assembly operations and that fluid pressure and vibration cannot cause a connection to become unfastened. In consequence, leakages cannot occur. The connecting portion of the pipe forms part of a system comprising the connecting member, union nut and pipe, whose relative stiffnesses are compatible with one another. Neither assembly forces, nor loads resulting from pressure pulses or vibration, can cause any settlement or unfastening of the connection. The axial force applied between nut and connecting member is such as to maintain secure and leak proof clamping conditions even under maximum operating pressure. The DIN specifications referred to are designed to withstand certain maximum permissible operating pressure levels.

It has been found that a pipe with a connecting portion maintaining secure holding conditions can be produced with a predetermined upsetting distance in the range 6mm to 8.5mm, the upsetting distance being suitable for the entire range of diameters of the standardised series. The rate of deformation is such that the connecting portion is not subject to settlement during assembly or repeated assembly. The upsetting distance has to be calculated from the outer pipe diameter within close limits of 2.5mm, with the upsetting distance increasing with increasing diameter. The pipe material and wall thickness are immaterial; they are only of significance in respect of the pressure force required to upset the pipe.

By observing the predetermined upsetting distance, it is ensured that during assembly no further axial deformation of the connecting portion of the pipe is caused.

Cone angles of 24' and 90' respective for the conical bore of the connecting member and that of the nut correspond to the standards for cutting rings according to DIN 3861 and 3870. These DIN standards also specify the tolerances in the cone angles: that for the cone angle of the conical bore of the connecting member is 30 minutes and that for the cone angle of the conical face of the nut is 20 minutes.

In a preferred embodiment, the conical face of the nut runs into the bore of the nut by way of a curved surface, to reduce the notch effect in this region.

The first tensioning face of the connecting portion of the pipe may start directly at the end of the pipe, or it is alternatively possible to provide a cylindrical portion of the pipe, in front of the first tensioning face which cooperates with the conical bore in the connecting member. In the assembled condition, such a cylindrical pipe portion lies within a cylindrical bore of the connecting member following the conical bore thereof.

To set a limit on tightening of the nut relative to the connecting member, the first tensioning face of the connecting portion of the pipe may end in an annular shoulder which comes to rest against an end face of the connecting member when the maximum tightening distance has been reached.

Improved sealing can be achieved in accordance with the invention by providing a sealing agent, which initially may be in liquid or paste-like condition, between the connecting portion and/or the adjoining regions of the pipe and the associated regions of the connecting member and the nut. Furthermore, it is possible yet further to improve sealing by providing a seal member in the form of a disc between the end face of the pipe portion disposed in front of the first tensioning face thereof and an annular shoulder of the bore of the connecting member.

On the outside of the connecting portion of the pipe there may be disposed a seal member which comprises a sealing projection clamped between 6 the end face of the connecting member and the contact shoulder of the connecting portion.

The invention also provides a method of producing a pipe with a connecting portion having a first conical tensioning face and a second conical tensioning face extending in the opposite direction, comprising upsetting the pipe by holding it in part of a multi-part upsetting tool of which respective relatively movable parts have conical pressing faces for forming the first and second tensioning, faces on the pipe, the pipe projecting from one tool part beyond the smallest diameter of the second conical pressing face provided in sai.d tool part towards a stop face provided in the other relatively movable tool part, the amount of said pipe projection corresponding to the length of a sealing cone in accordance with DIN standard 3865, May 1994 edition, which length is equal to the difference between lengths 13 and 1, for embodiment A, Figure 1 of said standard plus the length of the conical bore resulting from DIN standard 3861, May 1994 edition for a bore shape W, plus the length of an optionally provided projecting pipe portion for reception in, and shorter than, a cylindrical bore portion adjacent the standardised conical bore in a connecting member with which the pipe is to cooperate, and plus the length of a predetermined upsetting distance which is in the range 6mm to 8.5mm, the relatively movable tool parts being subject to an increasing upsetting force until they have moved relative to one another in the direction along the pipe axis by the predetermined upsetting distance which assumes its maximum value towards the greatest outer pipe diameter used.

In the case of thin-walled pipe, it may be advantageous to support the pipe in its bore during upsetting thereof.

After the upsetting operation, a sealing agent in liquid or paste-like form may be applied to at least one of the tensioning faces of the connecting portion of the pipe and/or to at least one pipe portion adjacent the connecting portion.

7 A sealing element may be provided on or in association with the pipe prior to upsetting thereof, and deformed therewith in the upsetting operation.

The invention will now be described by way of example with reference to the accompanying drawings, of which:- Figure 1 is an axial section through part of a first embodiment of pipe connection in accordance with the invention; Figure 2 is a view as Figure 1, but of a further embodiment of pipe connection in accordance with the invention; Figure 3 is a view showing an embodiment similar to that of Figure 2 but with a further modification., Figure 4 is an embodiment similar to that of Figure 3 but with the addition of a scaling member; Figure 5 is an embodiment modified from that of Figure 4 by the provision of a liquid or paste-like sealing agent; Figure 6 shows an embodiment with a further type of seal member; Figure 7 shows yet a further embodiment, wherein a seal member is provided between the connecting member and nut; Figure 8 is a view of an embodiment similar to that of Figure 3, with a seal member disposed on the outer surface of the connecting portion of the pipe, and also showing, separately, the configuration of the seal member; Figure 9 shows an embodiment having a seal element provided on the connecting portion of the pipe prior to upsetting thereof; Figure 10 shows a tool for upsetting the pipe, before and after the upsetting operation; Figure 11 shows a tool modified from that of Figure 10 by having a support internally of the pipe.

Referring firstly to Figure 1 of the drawings, this shows an assembled pipe connection comprising a connecting member 1, a nut 2 engaged therewith, and a pipe 3 with a connecting portion 4 of the pipe held between the connecting member and nut.

8 The connecting member 1 is in the form of a hollow body with an end face 5 from which a frusto-conical bore portion 6 extends into the body. The bore 6 is centered on the longitudinal axis 31 of the connection and tapers inwardly from the end face 5. At its smallest diameter, the frustoconical bore 6 leads into a cylindrical bore 7 which in turn terminates in an annular shoulder 8 followed by a through-bore 9 of smaller diameter than the bore 7. On the outer surface of the connecting member 1 there is a screw-thread 10 which starts from the end face 5. The conical bore 6 of the connecting member has a cone angle A which is 24', with a permissible tolerance of 30 minutes.

The nut 2 has an internally screw-threaded bore 11 which cooperates with the screw-thread 10 on the outside of the connecting member 1. The bore 11 is followed by a frusto-conical surface 13 whose cone angle B is 90' with a tolerance of 20 minutes. The conical face 13 extends in the direction opposite to that of the conical bore 6 of the connecting member 1. The conical face 13 leads into a cylindrical bore 15 by way of a curved face 14. For tightening, the outer surface of the nut may be provided with a surface configuration cooperable with a tightening implement such as a spanner. The connecting member 1 may also be provided with a surface portion cooperable with a holding or tightening implement, adjoining the thread 10. The connecting member may comprise two portions as illustrated disposed in "back-to-back" relationship, with respective conical bores 6 at opposite ends, the through bore 9 connecting the two ends of the connecting member. The lengths of the threaded portions 10, 12 of the connecting member and nut are such that the required number of threads overlap when the connection is securely tightened to provide the required tensioning force.

The connecting portion 4 of the pipe 3 has been formed by upsetting an end portion of the pipe to deform it from its normal diameter. The connecting portion 4 comprises a first frusto-conical tensioning face 16 adjacent the free end face 17 of the pipe, the tensioning face 16 corresponding in configuration to that of the conical bore 6 and being in surface contact therewith. The first tensioning 9 face 16 ends in a contact shoulder 18 which extends radially outwardly and is engageable with the end face 5 of the connecting member to limit the distance by which the nut 2 can be tightened. The contact shoulder 18 is followed by a portion which does not contact the connecting member or nut, which portion leads into a second tensioning face 19 which is frusto- conical in configuration and whose cone angle is 90'. There then follows the normal tubular portion 20 of the pipe 3 which extends through bore 15 of the nut 2.

In the embodiment of pipe connection shown in Figure 2, and the further embodiments shown in the following figures, parts correspondi.ng to those parts above described with reference to Figure 1 are identified by the same reference numbers as previously used, and the description is substantially confined to the differences between the embodiments.

In the embodiment of pipe connection shown in Figure 2, the pipe has a cylindrical portion 21 which is disposed in front of the first tensioning face 16 of the connecting portion 4 of the pipe. The outer surface of the portion 21 engages the cylindrical bore portion 7 of the connecting member 1, and the end face 17a of the pipe portion 21 ends in front of the annular shoulder 8 within the connecting member. There is contact around a frusto-conical surface between the conical bore 6 of the connecting member and the first tensioning face 16 of the pipe, and similar contact between the conical face 13 of the nut 2 and the second tensioning face 19 of the connecting portion 4 of the pipe 3. In this embodiment, however, the connecting portion 4 does not comprise a stop face for engagement with the end face 5 of the connecting member 1.

The embodiment shown in Figure 3 substantially corresponds to that of Figure 2. Again, a cylindrical pipe portion 21 is disposed in front of the first tensioning face 16 and is provided with an end face 17a which faces the annular shoulder 8. In this embodiment, the connecting portion 4 of the pipe has a contact shoulder 18 which limits the tightening distance of the nut 2 by coming to rest against the end face 5 of the connecting member 1. In this embodiment also, the second tensioning face 19 is in surface contact with the conical face 13 of the nut 2.

In Figure 4, the first tensioning face 16 provided on the connecting portion of the pipe is shorter than that of the embodiment shown in Figure 3. The outer surface 22 of the cylindrical pipe portion 21 merges into the first tensioning face 16 by a step 23 so that between the step 23 and the outer surface 22, facing the conical bore 6, there is defined a space wherein a seal member 24 is inserted. The second tensioning face 19 is conical in configuration, and has contact with the conical face 13 of the nut over a frusto-conical surface, The pipe 3 is guided out of the nut 2 by a cylindrical portion 20 of the pipe.

The seal 24 improves the sealing of the pipe connection. As compared to solutions where the connection between the pipe and the connecting member or nut is provided by a separate cutting or clamping ring, sealing conditions are improved due to the elimination of gaps.

The embodiment shown in Figure 5 differs from that of Figure 4 in respect of the sealing means employed. The first tensioning face 16 and the outer surface 22 of the cylindrical pipe portion 21 are provided with a sealing agent which is applied thereto in liquid or paste-like form, as indicated at 24a. Between the portion 20 of the pipe 3 projecting from the nut 2 and the bore 15 of the nut there is also provided a sealing agent 24a which has been applied in a liquid or paste-like form to the outer surface of the pipe 3.

Figure 6 shows a connection wherein the connecting portion 4 of the pipe 3 is clamped between the connecting member 1 and the nut 2, and wherein the end face 17a of the pipe portion 21 disposed in the bore 7 of the connecting member 1 engages a seal 24b in the form of a flat ring, whose other side rests against the annular shoulder 8 in the connecting member.

Figure 7 shows a further embodiment of pipe connection wherein the threads of the connecting member 1 and nut 2 are relatively shortened and, when the nut is fully tightened to the connecting member, overlap by only the length necessary to accommodate the maximum permissible axial tensioning force. The 11 bore of the nut 2 is provided with a face 41 which extends radially relative to the axis 31 of the connection, and between the face 41 and the end face 5 of the connecting member 1 there is clamped a seal 24c which seals the gap between the connecting member 1, the connecting portion 4 of the pipe, and the nut 2.

Figure 8 shows a further embodiment of pipe connection wherein a seal 24d is provided at the outer face of the connecting portion 4 of the pipe 3. The configuration of the seal 24d is shown as an inset to Figure 8, and it comprises a radially inwardly extending annular seating projection 42 which, when the pipe connection is tightened, is clamped between the end face 5 of the connecting member 1 and the radial contact shoulder 18 of the connecting portion 4 of the pipe 3.

Figure 9 shows yet a further embodiment of connection, wherein between the conical bore of the connecting member 1 and the first tensioning face of the pipe there is disposed a seal 43. The seal 43 is provided on the pipe 3 before the pipe has been deformed to form its connecting portion, the seal being deformed together with the pipe.

The shape of the connecting portion 4 of the pipe, as shown in the preceding figures, has been attained by deforming the pipe by an upsetting process using a tool as shown in Figure 10. The upper half of Figure 10 shows the tool and pipe prior to deformation of the latter, whilst the lower half of Figure 10 shows them after deformation of the pipe. The pipe is indicated generally at 36.

The tool comprises two parts namely a ram 26 and a gripping part or jaw 32, the two tool parts being movable relative to one another in the direction along the axis indicated at 31 of the pipe.

The ram 26 comprises a projection 27 with an end face 30 and a tapered frusto-conical pressing face 28. The pressing face 28 leads into a cylindrical bore 29 ending in a base face 29a. BY means of a powered drive, e.g. a hydraulic cylinder, the ram 26 may be moved towards the grippingjaw 32 in the direction of the axis 31. The jaw comprises two halves 32g, 32b for gripping the 12 pipe therebetween in a bore 35. The jaw 32 further comprises a bore 33 which is greater than the outer diameter of the projection 27 of the ram 26, thus enabling the projection to enter the bore 33. The bore 33 leads into a second frusto-conical pressing face 34 tapered in the direction opposite to the tapering direction of the pressing face 28 of the ram and which, at its smallest diameter Dmin? ends in the bore 35. Firmly to grip the pipe 36 when the two jaw halves 32a, 32b are moved towards one another, the bore 35 may he provided with means for increasing the co- efficient of friction with the surface of the pipe 36.

Prior to deformation, the pipe 36 is held by the jaw 32-a.wtth a length L of the pipe extending axially in the direction of the ram 26 beyond the bore 35 in the jaw. The length L comprises the sum of the length of the standardised sealing cone (obtained from the difference of lengths 13 and 1, of embodiment A, Figure 1, in DIN 3865, May 1994 edition, plus the length of the conical bore obtained from DIN 3861, May 1994 edition, bore shape W, plus the length of the optionally provided pipe projection (length Y) which is shorter than the cylindrical bore portion adjoining the standardised conical bore in the connecting member with which the pipe is to be used. The length of the upsetting distance X by which the ram is moved relative to the jaw of the upsetting tool is in the range 6mm to 8.5mm, depending on the outer pipe diameter.

In consequence, the projecting length L of pipe, for outer diameters of 1Omm and 38mm respectively of series S (heavy) and L (light), and without an additional pipe projection (i.e. Y=O), is calculated as follows:- Type 13 11 Ikeg Y X L 1OL 26 20 5.41 0 7 18.41 38S 48.5 39.5 6.35 0 8.5 23.85 fl 13 The pipe 36, by means of its end face 37, rests against the base 29a of the blind bore 29 in the ram 26. The ram is moved towards the jaw 32 by the upsetting distance X of 6mm to 8.5mrn, causing the wall of the pipe 36 to be curved outwardly and rest against the conical pressing face 28 of the ram 26 and the pressing face 34 of the jaw 32. At the same time a stop face is formed on the pipe by the end face 30 of the ram 26. The force P applied to the ram to cause it to deform the pipe is increased until the predetermined upsetting distance has been attained, the faces of the pipe being formed as required. The required force to cause the deformation of the pipe considerably exceeds the tensioning force S which is produced by tightening the nut relative to the connecting member in the pipe connection.

The embodiment of tool shown in Figure 11 differs from that of Figure 10 in that the ram 26 is provided with a supporting journal portion 40 which extends within the pipe 26 along its axis 31. In the course of upsetting of the pipe, the support of the latter by the journal portion 40 within the bore 39 of the pipe may be advantageous in the case of thin-walled pipes.

DIN Standards 3861 and 3865 (May 1994 editions) and translations of part thereof follow hereafter.

1 1,r DEN 3861 Taper bush type A: Taper bush with one taper. Taper bush type B: Taper bush with two tapers.

Interchangeability: Interchangeability of type A and B taper bushes is specified for angle of rotation-related assembly, see DIN 3859 Part 2 (at present in draft form).

If assembly is not determined by the angle of rotation, the special assembly instructions of the relevant manufacturer are to be observed.

Designation of a taper bush type A from the light series (L) for steel (St) pipe with an external diameter of 15 min:

Taper bush DIN 3861 - AL 15 St If the designation of the standardised part in existing documentation does not specify the type, then single taper bush type A shall apply in consideration of previous editions of the standard.

3 ?&teiial Normal design steel in accordance with DIN 3859. Other materials in accordance with DIN 3859 are to be agreed, specifying the order reference in accordance with DIN 3859 and added to the standard designation.

4 Design Surfaces at least A2P in accordance with DIN ISO 4042 X 5 1) 2) 3) 4) 5) Table 1

Series Pipe Type A lype lypee lype-,) -'pe -Iyp. ITYpe pc n 1 ts =Wcal A and B d, A B B 1 a B Is 1 -0.3 dim N d2 3 4 A and B A A 1 14 d, 0 p 1 d mix 1, 1 0.1 PN to DIN 0.2 Max. '19 1 1 i 1 0 2401 part 1 1 2 3 0.1 :0.0 811 5.'.5 4 4 6 2 5 4 LL very 5 6.6 7 - - 5 7 2,5 - - 6.5 5,5 6 100 7,6 8 - - 6 7 2,5 - - 0,2 7,5 5.5 a 9,6 10 - - 8 7 Z5 - - 9.5 5,5 17.8 F 9 7- 16 3 17.7 7 7 6 8.1 7 Lte taper a from series S - 5) 250 y) 123 7 12 14,3 7 L light 15 17.4 18 20 18 15 - 10 3,5 12 3,5 0.5 173 7 18 C) 21 24 21 is 3,5 lZ5 3.5 20,3 7,5 20,4 22 160 J24,4 25 27 25 22 - 10.5 3.5 13.5 U 20 7,5 28 30,4 31 33 31 28 - 10.5 3.5 13,5 35 3M3 7.5 100 38,1 40 42 38,5 353 13 5 lU 5 38 10.5 42 45.1 47 49 45.5 - 4Z3 lU 5 15,5 5 11 6 8,2 9 10 8.5 6 - 9 3 11.5 3 8,1 7 a 102. 11 12 10,5 8 - 9 3 11,5 3 10,1 7 630 12,4 13 14 13 10 - 10 3 12 3 1 u 7.5 12 14,4 15 16 15 12 - 10 3 12 3 14,3 7,5 S heay 14 16.4 17 20 17 14 - 10 3,5 12 3.5 0,5 M3 8 16 18.4 19 22 19 16 10,5 3,5 12 3,5 l" U 4W 23.0 24 27 23,5 20 1Z5 4 lU 4 2Z9 10.5 2B,0 29 33 28,5 25 - 12.5 4 1 55 4 27,9 12 33,1 35 39 33.5 30 - 13 5 16 5 33 13,5 38 250 - 43 49 1 42 - 38,3 13,5 5 16 5 41 16 41.1 Only for compressed air brake systems. Also for bore type W For bore type W Only applies to thematerial steel, see technical delivery conditions DIN 3859 See Explanatory Notes.

DIN 3861 1 1 P DIN 3861 Technical delivery conditions In accordance with DIN 3859, DIN 3859 Part 2 (at present in draft form) and DIN 3859 Part 3 (at present in draft form) Quoted standards DIN 2401 Part 1 Pressure and temperature specifications for components subjected to internal and external pressure; concepts and nominal pressure stages DU4 3859 Compression couplings; technical delivery conditions DIN 3859 Part 2 (at present in draft form) Compression couplings; Weldless compression couplings with- taper bush in accordance with DIN 2353; assembly instructions DIN 3859 Part 3 (at present in draft form) Compression couplings; Weldless compression couplings with taper bush in accordance with DIN 2353; test conditions for compression couplings DIN ISO 4042 Parts with threads; Galvanised coatings; Identical to ISO 4042:1989 Other standards DUNJ 2353 Non-soldering compression couplings with taper bush; complete couplings and overview P'revious editions DIN 3861: 09.57, 11.82 Amendments The following amendments have been made to the November 1982 edition:

a) Taper bush design divided into two taper bush types, type A and type B. Type A: taper bush with one taper Type B: taper bush with two tapers The dimensioning of the taper bushes has been extended in order to permit automatic assembly (classification of dimensions).

b) il DIN 3861 Explanatory Notes This standard has been drawn up by the Working Committee for Pipe Unions. After long discussion by the Working Cominittee, it was decided that the dimensioning of the taper bushes with 2 tapers (type B) would only be specified as minimum - and maximum dimensions. This is necessary since the individual manufacturers of taper bushes have produced various design sets.

As taper bushes and company documentation are so widespread, the following is to be observed: When ordering taper bushes for pipes with external diameters of 6 min, 8 min, 10 mm. and 12 min from the L series using the previous designations contained in old order documents, eg:

Taper-bush DIN 3861 - L 6 - St the following identical taper bush will be supplied:

Taper bush DIN 3861 - AS 6 - St.

International patent classification F16 L 019/08 DEUTSCHE NORM May 1994 Compression fintings Nipple ZV with O-ring for hole type W according to DIN 3861 DIN 3865 ICS 23.040.80 Supersedes 02.85 edition 1 Dimensions in mm 1 Field of application This standard applies to 24 nipples with 0-ring or only with 0-ring groove, which are used with welding connection (type A), -hose connection (type B) or in the case of screwed joints with adjustable direction (type B) in conjunction with the hole type W accordin to DIN 3861. The wall thicknesses resulting from the dimensions d, and d2 were calculated according to DIN 2413 (see Explanatory notes).

2 Dimensions, designation See below.

3 Material Nipple: standard material steel (St) according to DIN 3859, type A, weldable. Other materials according to DIN 3859 shall be agreed. 0-rings: standard material acrylonitrile-butadiene rubber (NBR) with a hardness (85 5) IRHD according to DIN 53519 Part 1 or Part 2. Other materials shall be agreed. (See note 2 on page 5).

4 Finish Type A: standard finish of surface protection Znph r 5 f according to DIN 50942 Type B: standard finish of surface protection according to DIN 20078 Part 1 Other finishes according to DIN 3859 shall be agreed.

Technical specifications

According to DIN 3859 2 Dimensions, designation The nipple need not correspond to the pictorial representation; only the specified dimensions DIN 3865 shall be observed.

Type A for welding connection X /-R-zlll z11 max.,/ zlmax z z 7 1 1 3 re ra -t -.9 Q. -GI a) 11 306 W- a) Finish at the discretion of the manufacturer 1 0-ring 2 Connection with hole type W according to DIN 3861 3 Retaining nut type A according to DIN 3870 Fig 1 RO, 2 RzS max.

3 1-0 DIN 3865 Type B for hose connection and screw joints with adjustable direction Other dimensions and data as for type A.

1 11 B.. ---" b) a) a) Thread corresponds to thread of retaining nut according to DIN 3870 b) Retaining nut and its connection to the nipple at the discretion of the manufacturer Fig 2 DIN 3865 Table 1

1) 2) 3) Series Pipe - Rated 0-fing 1 ype A and type 8 outside pressure Type B diameter PN to Inside diameter Cross-section el, d," d4 1, 1, Nominal DIN 2401 diameter width d, Part 1 toler. toler. +0.2 DN (from DIN 20066) min. max.

ances ances 0.1 -0.05 max. 0.2 0.14 1,5 6 2.5 7.5 19 32 25- 1.1 5 2.4 0.05 0.08- a 4 9.8 -fg- -n- -2r- _T7r- __2.7 250 10.09 10 6 - M_ _25 3 3 -79--9 1.5 0.08 12 7.5_ -14 1---25----NT-19- L 1 7.7 It Is advisable light M0.05 15 -4T ---TT 10.2 to provide a _fr- 163 Ir- U.20 2 - "5TW- -TF- --ff -rT- free pipe 28 U.22 2 -7zrug- -22---- l 7 24 2.5 39.5 32 1 5 20 15 17.2 tength and 2.5 0.03 35 -am _ZM -59--- I.C 32 that 0,37 M -4- 30.5 -W- 39 the to 36.2 retaining nut 4 0.14 1.5:to.oa 32 25 1.1 2.5 be -71513- -rr--:twm- 8 3 __9-.W_ 19 32 25 5 can pushed TU- 630 --rr- ---- 2.8 4 back behind 1.5 UM5 10 4 12;tu 3M -M- 3.6 the 0-ting 0.08 12 -8 -T - -M 41 32 ------ groove when heavy 16 1.5 changing the -rr- t -- 3Tr- -fr- 40.5 32 ----TT- 400 1b.3 0 20- -7,T- C-ring.

-W- M_ -7m -2m -47- 1u--- 16 ---Tr- 0.22 16 27.6 33.5 53.5 -1.8 - - 41.b -2y- 75- --To 25. 0.26 0.09 30 9. J.ú. 1 ib.b b7.5 4.4 1.5 25 19.5 247.rm- - i. UM5 35 W- -W M. -IM 64.5 48.5 #,440 3Z 45.4 301- The holes d, and d, max. are adapted to the rated pressures of the nipples and the functionally required minimum wall thicknesses under the 0-ring recess. Welding, flow or radiographic reasons may necessitate equal wall thicknesses at the connection point of nipples and pipes to be welded. If the hole dimensions d2 of the specified nipples are smaller than the inside diameter of the pipes in such cases, the nipple holes at the welding point can be countersunk at 300:t 100 to the inside diameter of the pipes. This shall be specially agreed when ordering. See Table 2 for dimensions. Applies only to steel, see Technical Specifications, DIN 3859 When nipples are equipped with 0-rings for the first lime 0-rings with different dimensions may also be used. The function of the nipple shall also be ensured with these 0-rings. 0-rings with the dimensions specified here shall be supplied for the provision of spare parts.

1 I;L DIN 3865 Designation of a nipple of type A in the heavy series (S) for pipe outside diameter 25 mm and an inside diameter of d2 = 16 mm, in standard finish made of steel (St) and O-ring made of the standard material: Nipple DIN 3865-AS 25 x 16 - St Designation of a nipple 'Of type B in the heavy series (S) of nominal width 20, in standard finish made of steel (St): Nipple DIN 3865 - BS20 - St O-rings according to this standard are designated with the inside and cross-sbction diameter and the material according to DIN 3771 Part 3. Designation of an O-ring (OR) with inside diameter 20.3 mm, made of NBR material with a hardness (85 5) IRHD (NBR 85): O-ring DIN 3865 - OR 20.3 x 2.4 - NBR 85 NOTE 1: On special request nipples of type A can also be ordered and supplied without O-ring (but with O-ring groove). (it is then the responsibility of the user to use a suitable O-ring). The designation of the above mentioned nipple of type A - Nipple DIN 3865 - AS 25 x 16 - St - but without O-ring (0) is then as follows:

Nipple DIN 3865 - AS 25 x 16 - St - 0 NOTE 2: If a different material is required instead of the standard material NBR with a hardness (85 5) IRHD for the O-ring for a nipple of type A or Type B, this shall be specially agreed and appended to the designation. The designation e.g. for a nipple of type A - Nipple - AS 25 x 16 - St - but with 0ring made of material FPM is then as follows:

Nipple DIN 3865 AS 25 x 16 - St - FPM Ll Table 2 (see explanatory note) DIN 3865 Series Pipe 0-ring " d," d, outside (inside 0.1 +0.2 diameter diameter -0.05 X for rated pressure PN cross-section 1w 160 250 400 630 diameter) 6 4 X 1.5 6 F-2. 5 2.5 2.5 - - -797 TT- 76 ---- I- 12 g- X 1.5 7.5 7.5 7.5 L is 12- x 2 10 -m ---T6- light --IT- --fT- - - ---Tr- 28 26 x2 23 32 x 2.5 -3r- - -n--x rg- 42 6 4 -X 1.5 2 7.5 x 1.5 10 6 6 6 6 4 S -14 heavy 16 12 x2 W- --7T 1G.3.2.4 20 14 14 14 13 --n-s -Xrz-- ---Tr- 19 19 -n-S -Xr4- 24 38 33.3 x 2.4 - 4) Standard finish according to Table 1 1 - 1 Quoted standards DIN 2401 Part 1 DIN 2413 DIN 3771 Part 3 DIN 3859 DIN 3861 DIN 3870 DIN 20066 DIN 20078 Part 1 DIN 50942 DIN 53519 Part 1 DIN 53519 Part 2 Further standards DIN 2445 Part 2 DIN 3853 retaining nuts, design sheet DIN 20078 Part 4 DIN 3865 Internally and externally pressure-stressed components; pressure and temperature data; terminology; rated pressure stages Steel pipes; calculation of the wall thickness to withstand internal pressure Fluid technology; 0-rings; materials, field of application Compression fittings; technical specifications Solderless screwed pipe joints; cutting rings; design and W type hole Solderless and soldered screwed pipe joints; retaining nuts Fluid technology; hose lines; dimensions, requirements Fluid technology; hose fittings; requirements, assembly instructions, testing Phosphating of metals; process principles, test methods Testing of elastomers; determination of the bail indentation hardness of soft rubber, International Rubber Hardness Degree (IRHD); hardness test on standard test pieces Testing of elastomers; determination of the ball indentation hardness of soft rubber, International Rubber Hardness Degree; hardness test on test pieces with small dimensions, microhardness test

Seamless steel pipes for fluctuating stress, precision steel pipes, rated pressures 64 to 400 Solderiess and soldered screwed pipe joints; threaded pins for Fluid technology; hose fitting; type D, with threaded pin in light series (L); dimensions 1 2-5 DIN 3865 DIN 20078 Part 5 Fluid technology; hose fitting; type E, with threaded pin in heavy series (S); dimensions ISO/DIS 8434-4 Metallic screwed pipe joints for fluid technology and general application; Part 4: welding nipple with nipple and 0-ring for 24 tapered connections Previous editions DIN 3865: 02.85 Amendments The February 1985 edition has been amended as follows:

a) Type B extended for screwed joints with adjustable direction b) c) d) e) f) g) Designation example for 0-rings included Standard material for 0-rings and reference to other materials included. Reference to different 0-ring dimensions when nipples equipped for the first time. Designation example for nipple type A with 0-ring groove, but without 0-ring included. Surface data included Nipple series L included Explanatory notes The 24' nipples with 0-ring listed in this standard apply to the connection to a) threaded pin according to DIN 3853 with type W hole (241) series L or series S according to DIN 3861 b) corresponding hose fittings, type D (series L) according to DIN 20078 Part 4 or type E (series S) according to DIN 20078 Part 5.

LIC, The Technical Specifications are laid down in DIN 3859.

The connection dimensions of the nipples are contained in ISO/DIS 8434-4.

DIN 3865 The requirements, assembly instruction and tests for hose fittings with nipple type B are specified in DIN 20078 Part 1, the dimensions in DIN 20078 Part 8 (series L) or DIN 20078 Part 9 (series S). In the case of nipples of type A dimension d2 was adapted to the rated pressures specified in Table 1 and the functionally required minimum wall thicknesses under the 0-ring recess. It was established in the discussions that within series S dimension d2 for the individual pressure stages should correspond approximately to the inside diameter of the pipes according to DIN 2445 Part 2, because this is necessitated by flow, welding and radiographic reasons. d2 dimensions for the rated pressures PN 100, PN 160, PN 250, PN 400 and PN 630 calculated for fluctuating stress according to DIN 2413 are listed in Table 2 as information. The same d2 dimensions apply to all the above rated pressures with the pipe outside diameters 6, 8 and 12 mm.. The d2 dimensions are specified only for rated pressures PN 160 and PN 250 for pipe outside diameters 30 and 38 mm, because with these sizes the design limit is rated pressure PN 250. In the case of nipples of type B the dimension d3 corresponds to dimension d., in DIN 20078 Part 8 (series L) or DIN 20078 Part 9 (series S). The connection of the nipple type B to the retaining nut is left to the manufacturer, the thread of the retaining nut complying with DIN 3870. With regard to the 0-rings it is pointed out that in the case of nipples of type A assembly takes place only after the welding and the 0-rings are therefore supplied loose. In the case of screwed hose connections the 0rings are mounted on the nipples, whereby the question of storage and ageing should be noted.

International patent classification F1 6 L 037110 F1 6 L 019103 i -?, - 1 The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (19)

1. A pipe for use in a Pipe connection of the kind specified, wherein the connecting portion is produced by upsetting the pipe in a tool comprising at least two parts movable relative to one another in the direction lengthwise of the pipe axis, by increasing the upsetting force until the two tool parts have moved relative to one another in the direction along the pipe axis by a predetermined upsetting distance, a first tool part comprising a first conical pressing face forming part of a bore and whose shape matches the conical bore in the connecting member, and further comprising a stop face for the end of the pipe; a second tool part comprising a second conical pressing face in the form of a bore and having a cone angle of 9T; the free pipe length which is to be subjected to the upsetting operation, and which projects from the smallest diameter of the second conical pressing face towards the stop face, corresponding to the length of a sealing cone in accordance with DIN standard 3865, May 1994 edition, which length is equal to the difference between lengths 13 and 1, as shown in embodiment A, Figure 1 of said standard plus the length of the conical bore resulting from DIN standard 3861, May 1994 edition, for bore shape W, and optionally plus the length of a projecting pipe portion for reception in, and shorter than, a cylindrical bore portion adjacent the standardised conical bore in the connecting member, and plus the length of the upsetting distance which is in the range 6mm to 8. 5mm, the upsetting distance assuming its maximum value towards the greatest outer pipe diameter used.

A pipe according to Claim 1 wherein a cylindrical end portion of the pipe is disposed in front of the first tensioning face of the connecting portion.

3. A pipe according to Claim 2 wherein a step is provided between the first tensioning face and the outer surface of said cylindrical pipe portion.

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4. said step.

5.

A pipe according to Claim 3 wherein a seal member is disposed in A pipe according to any one of the preceding claims wherein an annular shoulder is provided at the maximum diameter of the first tensioning face.

6. A pipe connection of the kind specified comprising a pipe according to any one of the preceding claims wherein the conical bore in the. connecting member extends from an end face thereof and its smallest diameter is followed by a cylindrical bore portion; the bore in the connecting member having a bore shape W in accordance with DIN standard 3861, May 1994 edition.

7. A pipe connection according to Claim 6 wherein the conical face of the nut joins a bore in the nut through which the pipe extends by way of a curved face.

8. A pipe connection according to Claim 6 or Claim 7 comprising a sealing agent, initially in liquid or paste-like condition, between the connecting portion and/or adjoining regions of the pipe and associated regions of the connecting member and/or nut.

9. A pipe connection according to any one of Claims 6 to 8, and including a pipe according to Claim 2, wherein a seal member is disposed between an end face of said cylindrical pipe portion and an annular shoulder in the connecting member.

10. A pipe connection according to any one of Claims 6 to 9 and including a pipe according to Claim 5, and wherein a seal member is disposed at the outside of the connecting portion of the pipe with a sealing projection clamped between the contact shoulder of the connecting portion and the end face of the connecting member.

11. A pipe connection according to any one of Claims 6 to 10 wherein a seal member is disposed between the end face of the connecting member and a radially extending face in the nut.

12. A method of producing a pipe with a connecting portion comprising a first conical tensioning face and a second conical tensioning face. extending in the opposite direction to the first, comprising upsetting the pipe by holding it in part of a multi-part upsetting tool of which respective relatively movable parts have conical pressing faces for forming the first and second tensioning faces on the pipe, the pipe projecting from one tool part beyond the smallest diameter of the second conical pressing face provided in said tool part towards a stop face provided in the other relatively movable tool part, the amount of said pipe projection corresponding to the length of a sealing cone in accordance with DIN standard 3865, May 1994 edition, which length is equal to the difference between lengths 13 and 1, as shown in embodiment A, Figure 1 of said standard plus the length of the conical bore resulting from DIN standard 3861, May 1994 edition for a bore shape W, plus the length of an optionally provided projecting pipe portion for reception in, and shorter than, a cylindrical bore portion adjacent the standardised conical bore in a connecting member with which the pipe is to cooperate, and plus the length of a predetermined upsetting distance which is in the range 6mm to 8.5mm, the relatively movable tool parts being subject to an increasing upsetting force until they have moved relative to one another in the direction along the pipe axis by the predetermined upsetting distance which assumes its maximum value towards the greatest outer pipe diameter used.

13. A method according to Claim 12 comprising supporting the pipe in its bore during upsetting thereof.

1 11 k

14. A method according to Claim 12 or Claim 13, comprising, subsequent to the upsetting operation, applying a sealing agent in liquid or paste- like form to at least one of the tensioning faces of the connecting portion of the pipe and/or to at least one of the adjoining pipe portions.

15. A method according to any one of Claims 12 to 14 wherein, prior to upsetting of the pipe, a sealing element is associated with the pipe and is deformed with the pipe in the upsetting operation.

16. A pipe connection substantially as hereinbefore described with reference to any one of Figures 1 to 9 of the accompanying drawings.

17. A pipe substantially as hereinbefore described with reference to any one of Figures 1 to 9 of the accompanying drawings.

18. A method of producing a pipe substantially as hereinbefore described with reference to Figure 10 or 11 of the accompanying drawings.

19. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.