WO2003052311A1

WO2003052311A1 - Pipe connection

Info

Publication number: WO2003052311A1
Application number: PCT/DE2002/004395
Authority: WO
Inventors: Udo Simon; Bernd Sedlak
Original assignee: Mapress Gmbh & Co. Kg
Priority date: 2001-12-14
Filing date: 2002-11-26
Publication date: 2003-06-26
Also published as: DE10164568C1; EP1454088A1

Abstract

The invention relates to a pipe connection, comprising a metallic press-fitting with at least one section for housing a sealing element, embodied with a bead-shaped cross-section. Said sealing element (3) comprises a cross-section which differs from the ideal circular cross-section similarly in all cross-sectional planes and, in the assembled but non-pressed state, taking account of the production tolerances for sealing elements (3), press fittings (1, 19) and pipes (4), the sealing element (3) has a dimension and adopts a position relative to the annular bead (2) and the pipe (4) which permits formation of a gap (18), which allows an escape of the medium for pumping and which is sealed tight after pressing.

Description

pipe connection

description

The invention relates to a pipe connection consisting of a metallic press fitting and a line pipe inserted therein according to the preamble of patent claim 1.

The production of an inseparable, tight connection of smooth-ended pipes with a press fitting comprising them is known. The sealing function of such a connection is achieved in that the sealing element inserted therein is elastically deformed by plastic deformation of the annular bead and, over a certain part of the cross-sectional circumference, comes to rest linearly on the surrounding area of the annular bead of the press fitting and the conduit. In order to absorb the longitudinal forces that occur with the corresponding internal pressure, the cylindrical region of the annular bead adjacent to the

Press fittings plastically deformed together with the conduit. During the pressing process, both the annular bead and the adjacent cylindrical region are deformed simultaneously by means of the actuating device.

As a rule, an uncompressed connection point leads to a detectable leak in the pressure test prescribed after installation. In special cases, however, it can happen that the tolerance pairing of the pipe and press fitting is so unfavorable that the sealing element is one, even if it is pushed in

undergoes only slight pre-deformation, which is sufficient to withstand the pressure test when the installation is removed. In later operation, however, the line "breathes". In the event of pressure surges caused by fast-switching valves and changes in temperature, relative movements can occur, so that if there is no axial securing due to non-compression, the pre-deformation of the sealing element that resulted is not sufficient to continue to ensure the tightness of the connection point.

To solve this problem, a sealing element has already been proposed (DE 19722935 C1), which has at least one section lying in the circumferential direction, which is provided with a cross section that deviates from the initial cross section. Preferably three sections lying symmetrically over the circumference with a different cross section are provided. The deviating cross-section is characterized by a bulge which extends over the circumference and in the cross-sectional plane and a recess which faces the inserted conduit and extends radially into the cross-section of the sealing element. The volume of the bulge in comparison to the initial cross section is at least as large as the volume of the recess missing from the initial cross section. Before the pressing, the recess of the sealing element forms a through opening for the medium in the axial direction.

A disadvantage of this solution is that the sealing element contoured in this way can only be produced in a complex manner and is therefore expensive.

The object of the invention is to provide a pipe connection with a press fitting and a conduit inserted therein, the sealing element of which is easy to manufacture and forms a leak when the pressure test is not pressed.

This object is achieved on the basis of the preamble in conjunction with the characterizing features of patent claim 1. Advantageous further developments are the subject of subclaims. According to the teaching of the invention, the sealing element has the same cross-section in all cross-sectional planes, which differs from the circular cross-section. Furthermore, the sealing element in the assembled but not pressed state - also taking into account the manufacturing tolerances for the sealing element, press fitting and conduit - is dimensioned and occupies a radial position with respect to the ring bead and conduit that there is a gap for the

Passage of the medium to be conveyed forms, which is sealed after the pressing.

The advantage of this arrangement can be seen in the fact that the sealing element is easy to manufacture, since it is the same in all cross-sectional planes and thus in a simple manner when assembled

Condition a leakage point is generated so that the pressure test is negative if this pipe connection point is not pressed. Such an uncompressed point can be re-pressed without problems and the pressure test repeated.

A prerequisite for the proposed solution is that the permissible tolerances for the pairing of press fitting, sealing element and conduit are kept within narrow limits in order to be able to form a gap even in the case of an unfavorable overlap.

This pipe connection can be used for all types of press fittings made of metal, be it carbon steel, stainless steel, copper, copper alloys, brass or titanium. An advantage of the proposed pipe connection can be seen in the fact that, with the exception of the sealing element, nothing needs to be changed in the basic design of the other elements and that the pressing tools which are in large numbers on the market can also be used unchanged. The only condition is system conformity for the three interacting elements press fitting, sealing element and conduit, since the advantageous gap formation cannot be guaranteed when mixed with elements from other systems.

In the assembled state, the sealing element preferably comes into contact with the inner wall of the annular bead at least at two circumferential positions, and the gap is formed between the sealing element and the outer surface of the pipe. Tests have shown that the volume of the bulge compared to the ideal circular cross section must be at least as large as the volume of the recess missing for the circular cross section.

The volume of the bulge is preferably at least 5% larger than that of the recess.

A profile, which is similar to a somewhat flattened hose, has proven to be a favorable form for the different cross-section, the flattened side facing the conduit.

Further features, advantages and details of the invention result from the following description of exemplary embodiments shown in a drawing. Show it:

Figure 1 half-sided longitudinal section of a pipe connection in the assembled state before pressing with gap formation on the conduit

2 shows an enlarged view of the annular bead area FIG. 3 like FIG. 2 but after the pressing

Figure 4 as Figure 1 but another embodiment of the press fitting

Figure 5a, the sealing element in plan view

Figure 5b shows a section in the direction A - B in Figure 5a

Figure 5c shows the detail Z in Figure 5b

FIG. 1 shows a longitudinal section of a pipe connection designed according to the invention in the assembled state before the pressing. The pipe connection shown here consists of a press fitting 1, the front end of which has an annular bead 2 with a sealing element 3 designed according to the invention, which can be inserted therein.

A smooth-ended conduit 4, the insertion direction 5 of which is indicated by an arrow, is inserted into the press fitting 1. Seen in insertion 5, a cylindrical section 7 adjoins the ring bead 2 with an oblique transition 6. This merges with a shoulder 8 into a second cylindrical section 9, the inside diameter 10 of which is smaller than the inside diameter 11 of the first cylindrical section 9. On the inside, the inserted conduit 4 comes to rest. Contrary to the insertion direction 5, in this exemplary embodiment the annular bead 2 merges into an end region 12, the leg of which is almost perpendicular to the axis 13 of the conduit 4.

FIG. 2 shows an enlarged representation of the area of the annular bead 2, so that the design according to the invention can be seen more easily than in FIG. 1. In the assembled state, however, before the pressing, the inserted sealing element 3 comes into contact with the inner wall 14 of the annular bead 2 at least in two circumferential positions, in extreme cases only touching, as a rule with slight prestress. The inserted pipe 4 has an outer diameter 15 with respect to the press fitting 1 and the sealing element 3, which, even taking into account the manufacturing tolerances for the press fitting 1, sealing element 3 and pipe 4, is always smaller than the inner diameter 16 of the inserted sealing element 3. This ensures that a gap 18 is formed between the outer surface 17 of the conduit 4 and the sealing element 3. This gap 18 is the deliberately created leak point for the medium to be sealed, so that the pressure test would be negative if this pipe connection point were not pressed. Only after the compression, the sealing element 3 comes to bear sealingly against the outer surface 17 of the conduit 4 (FIG. 3). FIG. 4 shows a second embodiment of a press fitting 19 with the same gap formation in the same longitudinal section as FIG. 1, the same reference numerals being used for the same parts. In this embodiment, the press fitting 19 additionally has a third cylindrically shaped section 7b which faces the insertion direction 5. In addition, the annular bead 2 has two adjoining oblique transitions 6a, 6b.

In this embodiment, too, in the assembled state, the inserted sealing element 3 comes into contact with the inner wall 14 of the annular bead 2 at least in a touching manner, as a rule, with slight prestressing. A gap 18 is formed under the same conditions as previously explained in detail in FIG. 2.

FIGS. 5a to 5c show a top view, a section and an enlarged view of the sealing element 3 designed according to the invention. As can be seen in FIG. 5c, the cross section deviating from the circular cross section resembles a somewhat flattened hose. The cross-section is characterized by four sectoral sections I to IV, with sections II and III being double mirror images.

The first sectoral section I lies above the horizontal central axis 20 and symmetrically to the vertical central axis 21 with a circular contour, the center M of which is equal to the center of the sealing element 3. The first sectoral section I has a radius R. This first sectoral section I is adjoined on the right and left by a circular sectoral section II lying in the region of the horizontal central axis 20. The center point M1 is offset twice from the center point M of the sealing element and the radius R1 is larger than the radius R of the first sectoral section I. Below the horizontal central axis 20, the cross section is also formed by two sectoral sections III lying on the right and left with a circular contour thereof Center points M2 likewise lie twice offset from the center point M of the sealing element 3 and whose radius R2 is smaller than the radius R of the first sectoral section I. A sectoral section IV with a straight contour symmetrical to the vertical central axis 21 forms the lower end. All sectoral sections I to IV merge tangentially.

In order to clarify the deviation from the circular cross section, the ideal circular cross section has been drawn into the cross section of the sealing element 3 in FIG. 5c with dashed lines. The areas of the bulge 22, 22 'and the area of the recess 23 can now be clearly seen.

LIST OF REFERENCE NUMBERS

Claims

claims

1. Pipe connection, consisting of a metallic press fitting, which has at least one section with a bead-like cross-section, receiving a sealing element and an adjoining section facing towards the insertion side and / or facing away from the insertion side, the cylindrical section facing away from the insertion side having an inwardly extending shoulder merging into an adjoining cylindrically shaped section, the inside diameter of which is smaller than the other cylindrically shaped sections and a metallic conduit, the smoothly formed end region of which, after being inserted into the press fitting, abuts the heel of the first cylindrically shaped section comes and by means of a press tool comprising the press fitting and having at least two press jaws, an inseparable tight pipe connection is formed after the press tool is closed, whereby during the pressing the

Press jaws act both on the annular bead including the sealing element inserted therein and on the cylindrical portion of the press fitting facing and / or facing away from the insertion side, the sealing element having at least one portion lying in the circumferential direction, which has a cross-section deviating from the circular cross-section in the form of a The bulge in the cross-sectional plane and a recess facing the inserted conduit and extending radially in the cross-section of the sealing element are characterized in that the sealing element (3) is the same in all cross-sectional planes

Circular cross-section has a different cross-section and, in the assembled but not pressed state, also taking into account the manufacturing tolerances for the sealing element (3), press fitting (1, 19) and conduit (4), the sealing element (3) is dimensioned in this way and in relation to the ring bead ( 2) and the conduit (4) occupies a radial position that allows the medium to be conveyed to pass through

Gap (18) forms, which is sealed after the pressing.

2. Pipe connection according to claim 1, characterized in that the sealing element (3) on the inner wall (14) of the annular bead (2) comes into contact with at least two circumferential sections and between the sealing element (3) and the outer surface (17) conduit (4th ) the gap (18) is formed.

3. Pipe connection according to claim 1 and 2, characterized in that the volume of the bulge (22, 22 ') compared to the ideal circular cross section is at least as large as the volume of the recess (23) missing for the circular cross section.

4. Pipe connection according to claim 3, characterized in that the volume of the bulge (22, 22 ') is at least 5% larger than that of

Recess (23).

5. Pipe connection according to one of claims 1 to 4, characterized in that the different cross section is similar to a somewhat flattened hose.

6. Pipe connection according to claim 5, characterized in that the different cross-section six intersecting sectoral

Sections (I - IV), of which at least three are circular.

7. Pipe connection according to claim 6, characterized in that one of the sectoral sections (IV) is straight. Pipe connection according to claims 5 to 7, characterized in that above the horizontal central axis (20) and symmetrical to the vertical central axis (21) extends at least over 90 ° a first sectoral section (I) with a circular contour, the center point (M) of which is the same the center of the

Sealing element (3) and this first sectoral section (I) is connected on the right and left in each case a circular sectoral section (II) extending in the region of the horizontal central axis (20), the center (M1) of which is offset twice from the center (M) of the sealing element (3) and whose radius (R1) is larger than the radius (R) of the first sectoral section (I) and the part of the sealing element (3) lying below the horizontal central axis (20) is formed from two symmetrical to the perpendicular central axis (21) lying sectoral sections (III) with a circular contour, the center points (M2) of which lie twice offset to the center point (M) of the sealing element (3) and whose radii (R2) are smaller than the radius (R) of the first sectoral section ( I) and a sectoral section (IV) lying symmetrically to the vertical central axis (21) with a straight contour represents the lower end, with all sectoral sections (I - IV) tangential merge.