DE29819537U1 - Pipe connector - Google Patents

Description

Pipe connector

The invention relates to a pipe plug connection for the tight connection of plastic pipes, in particular of essentially pressureless drain pipes in sanitary installations.

Pipe plug connections for tightly connecting plastic pipes are known. DE-OS 284 43 08 describes a fitting made of dimensionally stable plastic for pipe connections, with a sleeve-like end piece into which the end of a smooth connecting pipe section can be inserted with an elastic sealing ring element in between. Among other things, this document also suggests that the elastic seal be made from a thermoplastic elastomer (TPE) and molded directly onto the plastic fitting in a two-component injection molding process. As experience in practical use shows, the seal of such a pipe connection is not permanently tight, because thermoplastic elastomers in no way achieve the elasticity of rubber, and tend to "flow" under constant load. Therefore, the above-mentioned description already contains the suggestion of using an additional expansion ring, which can be pressed axially like a wedge into an annular gap accessible from the outside of the sleeve, and which the seal

Forsteniieder Allee 59 D-81476 Munich Tel. +49 089-745541-0 Fax+49 089-7593869

SchaeferstrasselS D-44023 Heme Tel.+49 02323-95440 Fax+49 02323-12232

McK-Beclcrnarm-StTOße 23a D-04109 Leipzig Tel. +49 0341 -2113818 Fax+49 0341 -2113818

Expianada de Espana No.3 ES-03002 Alicante

Phone +49 089-745541-0

Fax+49 089-7593869

HSB. Hypo Service-Bank FiBaIe Leipzig Account number 5690428441 (bank code 860 20 700)

under additional tension. However, this solution is expensive and difficult to install.

DE-OS 293 60 16 also discloses a fitting for plugging pipes with a molded-on TPE seal, in which the seal protrudes axially outwards from the front of the socket after demolding and is turned inwards before the pipe connection is installed in order to create a tight connection to the outer surface of the inserted pipe end over a longer sealing area provided with circumferential sealing ribs. This pipe connection also does not guarantee reliable sealing over a longer period of time due to the significantly lower permanent elasticity of the thermoplastic elastomer compared to rubber. In addition, because the inserted pipe end is pushed back and forth in the turned-over seal during installation in order to adjust the length of the pipe connection, there is a risk that when the inserted pipe end is pulled back, the turned-over seal will be pulled outwards again, making installation work more difficult.

The invention is therefore based on the object of creating a pipe plug connection for tightly connecting plastic pipes using a seal made of a thermoplastic elastomer connected to a pipe part, e.g. by means of a two-component injection molding process, which ensures a permanently tight connection and can be easily installed without additional clamping elements.

The object is achieved according to the invention by the characterizing features of claim 1. Advantageous embodiments of the invention are the features of claims 2 to 12.

The invention will be explained in more detail below using an embodiment in conjunction with the drawing.

Figure 1 shows two pipe ends that can be plugged together to form a pipe plug connection in longitudinal section.

Figure 2 shows, on an enlarged scale, details of the pipe ends shown in longitudinal section in Figure 1.

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As can be seen in Figure 1, in order to produce a tight pipe connection between the two pipe ends 1 and 2, the pipe end 2, which has a smooth, essentially cylindrical outer surface 3, can be inserted into the inner region 4 of the sleeve-like pipe end 1.

In order to ensure a permanently tight connection between the two plastic pipes and at the same time a problem-free installation, the sleeve-like pipe end 1 has an inner area 4 with a firmly connected sealing ring element 5 made of a thermoplastic elastomer (TPE). The inner area 4 of the sleeve-like pipe end 1 also comprises an axially relatively long, essentially cylindrical section 6, which is paired with the diameter dl of the cylindrical outer surface 3 of the smooth pipe end 2 in a clearance fit. This clearance fit ensures that the pipe ends can be easily moved relative to one another during installation, so that distance differences between the two pipe ends in the order of several centimeters can be compensated.

A permanent seal is achieved by an axially relatively short section 7 having a reduced diameter d3 in the inner region 4 of the sleeve-like pipe end 1, which produces a press fit in pairing with the diameter dl of the cylindrical outer surface 3 of the smooth pipe end, as well as a section 8, on the inner surface of which the sealing ring element 5 is arranged, and whose pairing with the cylindrical outer surface 3 of the smooth pipe end 2 at least partially produces a press fit. By combining the permanently elastic pressure exerted by the plastic material of the pipe ends in section 7 with the essentially adjacent arrangement of the sealing ring element 5, which in turn interacts at least partially with the outer surface 3 of the smooth pipe end 2 in a press fit, the sealing effect of the pliable elastic-plastic sealing ring element 5 is reinforced by the permanently elastic pressure of the plastic material, so that it can still follow any changes in the position of the pipe ends 1 and 2 relative to one another even at times after installation, and the seal is thus permanently maintained.

In the advantageous embodiment of the invention, which is shown in Figures 1 and 2, the section 8 of the inner region 4 of the

The sealing ring element 5, which is firmly connected to the sleeve-like pipe end 1, is arranged directly adjacent to the section 7 of the inner region 4, which is reduced to a diameter d3. As a result, the combination effect described above between the permanent elasticity of the pipe material and the conformability of the elastic-plastic sealing ring element 5 functions particularly effectively.

Furthermore, it is advantageous if the sealing ring element 5, viewed in the insertion direction of the smooth pipe end 3, is arranged in front of the reduced-diameter section 7 of the inner region 4 of the sleeve-like pipe end 1.

A further advantageous embodiment of the invention consists in that the sleeve-like pipe end 1 is widened in a funnel shape from the section 7 with reduced diameter to the front side 9 of the pipe end 1 in a section 8 to an inner diameter which is larger than the diameter dl of the cylindrical outer surface 3 of the smooth pipe end 2, the sealing ring element 5 being firmly connected to the inner surface of the funnel-shaped widened section 8. The funnel-like widening makes it easier to insert the smooth pipe end 2 into the sleeve-like pipe end 1. A funnel-shaped widening of the section 8 at an angle α to the pipe axis of approximately 15° is particularly advantageous. Also advantageous is an oversize of the press fit between the reduced-diameter section 7 of the socket-like pipe end 1 and the outer surface 3 of the smooth pipe end 2, which is at least about 0.2 mm for a nominal diameter of the pipes to be connected of 40 mm .

The sealing ring element 5 is expediently molded onto the inner surface of the funnel-shaped widened section 8, in particular by a two-component injection molding process in a tool.

Finally, with a nominal diameter of 40 mm for the pipes to be connected, the annular edge 11 of the sealing ring element 5 protruding inwards next to the reduced-diameter section 7 should expediently have a projection f of approximately 0.8 mm.

A chamfer 15 of the cylindrical outer surface on the front side 13 of the smooth pipe end 2 is also advantageous. This chamfer also facilitates

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the introduction of the smooth pipe end 2 into the socket-like pipe end 1 and also prevents any damage to the inner surface 12 of the sealing ring element 5 when mating the two pipe ends. The chamfer should be arranged at an angle β to the pipe axis between approximately 30° and 45°.

Polypropylene (PP) can be used as a suitable material for the plastic pipes.

Compared to the known pipe plug connections with an elastic TPE seal that is fixed to a pipe element, e.g. molded onto it using a two-component injection molding process, the advantages are that the pipe plug connection according to the invention leads to a permanently tight connection, that it does not require additional clamping elements to pressurize the seal, such as union nuts or expansion rings, and that it can be installed without complications.

Claims (12)

Protection claims 1. Pipe plug connection for permanently sealingly connecting plastic pipes, comprising a sleeve-like pipe end (1) with an inner region (4) and a sealing ring element (5) made of a thermoplastic elastomer that is firmly connected to the latter, and a smooth pipe end (2) that can be inserted into the sleeve-like pipe end (1) and has an essentially cylindrical outer surface (3), characterized in that the inner region (4) of the sleeve-like pipe end (1) has an axially relatively long, essentially cylindrical section (6) that is paired with the diameter (dl) of the cylindrical outer surface (3) of the smooth pipe end (2) in a clearance fit, an axially relatively short section (7) with a reduced diameter (d3) that produces a press fit in pairing with the diameter (dl) of the cylindrical outer surface (3) of the smooth pipe end (2), and a section (8) that is essentially adjacent to the section (7), on whose Inner surface of the sealing ring element (5) is arranged, and its mating with the cylindrical outer surface (3) of the smooth pipe end (2) at least partially produces a press fit. 2. Pipe connector according to claim 1, characterized in that the sealing ring element (5) firmly connected to the section (8) of the inner region (4) directly adjoins the section (7) of the inner region (4) with a reduced diameter (d3). 3. Pipe plug connection according to claim 1 and/or 2, characterized in that the sealing ring element (5) firmly connected to the inner region (4) of the sleeve-like pipe end (1) is arranged in front of the reduced-diameter section (7) of the inner region (4), as seen from the front side (9) of the pipe end (1). 4. Pipe plug connection according to one or more of the preceding claims, characterized in that the sleeve-like pipe end (1) is reduced from the section (7) with reduced diameter to the front side (9) of the pipe end (1) to an inner diameter (d4) which is larger than • «nt « the diameter (dl) of the cylindrical outer surface (3) of the smooth pipe end (2) is widened in a funnel shape, and the sealing ring element (5) firmly connected to the inner surface of the funnel-shaped widened section (8) of the inner region (4) of the socket-like pipe end (1) is formed on the inner surface of the funnel-shaped widened section (8). 5. Pipe connector according to claim 4, characterized in that the sealing ring element (5) is molded onto the inner surface of the funnel-shaped widened section (8), in particular by a two-component injection molding process in a tool. 6. Pipe plug connection according to claim 4 and/or 5, characterized in that the section (8) is widened in a funnel shape at an angle (α) of approximately 15° with respect to the pipe axis (14) in the direction of the end face (9) of the sleeve-like pipe end (1). 7. Pipe plug connection according to claims 4 to 6, characterized in that the inner surface of the sealing ring element (5) runs essentially parallel to the direction of the inner surface of the funnel-shaped widened section (8), and next to the section (7) of the inner region (4) with reduced diameter, there is an annular edge (11) projecting inwards from the diameter (d3) of the section (7) by an overhang (f), and a truncated cone surface (12) closed from this edge (11) to the inner edge (10) of the end face (9) of the sleeve-like pipe end (1). 8. Pipe plug connection according to one or more of the preceding claims, characterized in that the interference fit between the reduced-diameter portion (7) of the socket-like pipe end (1) and the outer surface (6) of the smooth pipe end (2) is at least about 0.2 mm for a nominal diameter of the pipes to be connected of 40 mm. 9. Pipe connector according to one or more of the preceding claims, characterized in that the annular edge (11) projecting inwards next to the reduced diameter section (7) the sealing ring element (5) has a projection (f) of approximately 0.8 mm for a nominal diameter of the pipes to be connected of 40 mm. 10. Pipe plug connection according to one or more of the preceding claims, characterized in that the cylindrical outer surface on the front side (13) of the smooth pipe end (2) has a chamfer (15). 11. Pipe connector according to claim 8, characterized in that the chamfer (15) is arranged at an angle (ß) to the pipe axis between approximately 30° and 45°. 12. Pipe plug connection according to one or more of the preceding claims, characterized in that the plastic pipes are made of polypropylene.