WO1998021518A1

WO1998021518A1 - Plastic sleeve for plastic pipes or fittings

Info

Publication number: WO1998021518A1
Application number: PCT/AT1997/000240
Authority: WO
Inventors: Regina Schnallinger; Helmuth Michael Schnallinger
Original assignee: Regina Schnallinger; Helmuth Michael Schnallinger
Priority date: 1996-11-08
Filing date: 1997-11-06
Publication date: 1998-05-22
Also published as: AU4766697A

Abstract

A plastic sleeve (2) for plastic pipes (1, 3) or fittings, in particular for high-pressure water pipes, has at least one ring-shaped groove (6) for receiving a sealing ring (8) that presses a pipe end (3) inserted into the plastic sleeve (2). A clip (9) that surrounds the outside of the sleeve (2) at least in the area of the ring-shaped groove (6) is provided to maintain the sealing ring (8) under a constant radial prestress by pressing together the sleeve (2).

Description

Plastic sleeve for plastic pipes or fittings

The invention relates to a plastic sleeve for plastic pipes or fittings, in particular for pressure pipe water pipes, with at least one ring groove for receiving a sealing ring which presses against an inserted, undeformed smooth pipe end.

Sockets of this type are intended to enable a plug-in connection of pipes of any length and also of pipes cut to length in the end region which remains in the undeformed state or of pipes and different fittings, such as elbows or T-pieces, branches, etc. The advantage of plug-in connections is basically that the respective connections can be made in a short time without substantial use of equipment. With all known plug connections, leaks in the connection can occur, in particular over time. In the case of freely laid, essentially unpressurized sewage pipes or small pipes on drains, this leak is usually accepted. The occurrence of leaks in pressure pipe, water and sewage pipes is much more unpleasant if they are not laid freely, but in the ground or in shafts etc. For pipes of this type, usually made of high-pressure polyethylene, which are often exposed to high pressures up to PN 16, for example, and which also have relatively large can have a diameter of up to and over 250 mm, a high likelihood of maintaining a tight seal is required, since leaks that occur result in a very large amount of work and, in many cases, digging or chiselling work for renovation. In the case of a known sleeve, which makes a plug connection possible, in addition to the ring groove receiving the seal, it has a further ring groove for receiving a locking ring, which has a conical guide surface for this locking ring, which drops towards the end of the sleeve and guides the locking ring which coincides with it Ring combs press against the inserted pipe end and when pulling back this pipe end compresses under the action of the cone, so that the ring combs press into the pipe wall. In practice, leaks also occur with such plug connections. These can be explained as follows: Pressure surges occur in pressure pipe water pipes, which lead to minimal longitudinal adjustments or longitudinal vibrations of the pipes connected to each other. As a result of these vibrations, there is a pumping movement, by means of which the clamping ring is adjusted slightly, but continuously, so that its contact pressure on the pipe is reduced. Furthermore, the vibrations also reduce the sealing effect. To make matters worse, fine sand and other contaminants can occur in the pipelines laid in the ground via the socket end, which brake the clamping ring during its return movement into the full clamping position and can even penetrate into the seal, so that it leaks. Socket connections in which the parts to be connected, for example pipes, are not exactly axially aligned are particularly at risk of leaking, but, as is often the case with pressure pipelines, are slightly inclined to one another. There is then an unfavorable load on the pressure ring and also on the seal, which can be squeezed out of the ring groove receiving it even in extreme cases. Since one has to rely on a particularly high dimensional stability of the sleeve to support the clamping ring, sleeves with a very large wall thickness have to be used, which so far have not been able to be formed directly from the pipe end by widening in pipes, but are produced in a separate injection molding process and at the pipe ends are welded, which increases the total cost of the connections significantly, in practice compared to pipes with molded sleeves about ten times. Because of the occurring Dangers with plug connections are usually endeavored not to make the connections in high pressure water pipes as plug connections, but to provide the pipes with pipe sockets, to plug them together and then to weld them. Welding machines are expensive to buy, so that their use only pays off for long pipelines, i.e. for complete supply systems, whereas for house connections etc., the costs for producing the individual pipe connections often exceed the material costs for these pipes, so that here, if possible, with plug connections should be worked.

The problems described in connection with pressure pipe water pipes arise in a similar way with other pipes made of plastic pipes and also with pipes made of other plastics, such as those e.g. be used for household waste water. Other polyolefins, PVC, etc. can also be used here as production material.

In the case of pipe connections according to AT 363743 B and DE 3 002 396 A, which differ generically from sleeves or pipe connections of the type mentioned at the beginning, an annular groove is formed within a sleeve at one pipe end, this annular groove being a lip seal which is acted upon by the line pressure and pressurized records. The other pipe end, which can be inserted into the sleeve, also has a deformation which can be designed as an annular groove pushed through to the outside or as a collar placed in the form of a thickening. The last-mentioned pipe end is generally not inserted over the full length into the sleeve and a retaining clip is attached, the main task of which is to grip the two pipes by attacking the mostly bevelled outer sides of the ring grooves or the To tighten the ring groove and the collar in the longitudinal direction, for which purpose the clamp is provided with side flanks adapted to the bevels, so that it exerts a pulling action on both parts during the tensioning due to the action of the conical surfaces sliding on one another. In order to achieve this train, there must be enough free space so that the inclined surfaces can come into effect, but in the rest of the area no pressure is exerted by the clamp on the pipe and sleeve, which means that the clamp that seals the seal taking annular groove and also the remaining sleeve area not deformed in the radial direction. The outer clamp prevents the two parts from pulling apart, but misalignment leads to the disadvantages already described. Apart from this, connections of this type could not prevail, since here deformations, i.e. complex machining, are necessary at both pipe ends and it is therefore also impossible to cut a pipe at the end free of the sleeve to the desired routing. In the laying area there are practically nowhere the necessary tools and facilities to attach the retaining ring grille or the retaining collar.

The object of the invention is therefore to eliminate the disadvantages shown and to create a plastic sleeve which, even when used for pressure pipelines, very likely ensures the production of permanently sealed plug connections, the costs for the manufacture of the sleeve itself and also for the production of the connections should keep within reasonable limits, far below the price of welded joints.

In principle, the stated object is achieved by a clamping clamp which surrounds the sleeve at least in the area of the ring groove for the permanent radial prestressing of the sealing ring by compressing the sleeve.

The solution according to the invention, which in retrospect appears to be extremely simple, has decisive advantages. First of all, it is possible and conceivable to use sleeves formed directly on the pipe end for the production of plug-in connections, even in the case of high-pressure pipes, since the sleeve is additionally supported by the attached clamp. In contrast to the plastic material, which tends to change its shape due to aging or under permanent loads, in particular to widen the sleeve or ring groove, clamps can be used that are not subject to any deformation due to aging. Stainless material, eg aluminum, or stainless steel sheet is preferably used, in special cases also galvanized or coated steel sheet. The clamping pressure generated is therefore retained and deformation of the sleeve itself is avoided by the external support. Since the Ring groove becomes a rigid body due to the clamp, even diagonally attached connecting pipes can no longer deform the seal to leak. The kink or the force application point lies outside the outer edge of the clamp due to the reinforcement.

The clamp can be designed as a split pipe clamp that can be tightened with screws. Such clamps can be used on pipes, i.e. preassembled on end sleeves of pipes or on connection sleeves of fittings as well as on normal connecting sleeves, so that on site only tightening the screws after inserting the connecting pipe or other connecting pipe piece is necessary. Due to the subsequent bracing, it is even possible to make the relaxed inner diameter of the seal and even the sleeve a little larger (ie in the millimeter range) than with conventional sleeves for plug connections, which makes it easier to plug together, especially with sleeves of large diameter, and also the risk of Damage to the seal when inserting the connecting pipe is reduced. In addition to the shape of the tension clamp mentioned, it is also possible to design the tension clamp as a tension ring, slotted sleeve or clamp working with steel tension bands.

In the case of a sleeve which, in addition to the ring groove receiving the seal, has a further ring groove for receiving a conical locking ring which prevents the tube from being pulled out, it is provided according to the invention that the clamping clamp also extends outside over the longitudinal region of the groove receiving the locking ring and holds this locking ring in the clamping position. With this construction, operational safety is increased. In most cases you can get by without such locking rings, so choose simpler sleeve designs, taking care that the sleeve connection holds even under tensile loads.

One possibility for solving the latter task is that the tensioning clamp extends over the area of the ring groove receiving the seal and a sleeve end piece provided at the insertion of the sleeve, so that the clamp in the tensioned position also extends this end piece around the connected one Squeeze pipe. Here, a clamp connection is made between the socket and the subsequent pipe, also in the socket end area. To increase the clamping effect, the inside of the sleeve and, if necessary, also the pipe end to be connected can be provided with a surface profile, for example scoring, in this area. If the grooves run in the form of ring grooves, then a kind of labyrinth seal is obtained when the sleeve end piece is compressed, which inherently prevents or prevents the ingress of dirt or other impurities into the sealing area.

The end piece can have longitudinal slots in its wall or weak points running in its longitudinal direction to facilitate the compression.

According to another possibility, the end piece has a larger inside diameter than the inside diameter of the connected pipe and can be pressed against this pipe by means of the clamping clamp while reducing its diameter.

Additional security against leakage and also against the ingress of dirt is achieved if the end region of the sleeve accommodates an additional pressure or sealing ring that can be compressed with it and pressed onto the connected pipe. Of course, not only one, but two or more, even different types of seals can be arranged one behind the other in the inner region of the sleeve, each of which can be compressed via the clamp. So far it has been assumed that clamps are used which are subject to an even reduction in diameter. Even adjustment can be achieved by adapting the clamp to the outer shape of the sleeve. If, on the other hand, for example in the area of the ring groove and in the socket end area, there is provision for the tensioning point to rest on the socket in the relaxed state and some air in the rest of the area, then these system areas are first compressed during the bracing, after which the further socket areas can only be detected. It is also possible to use longitudinally divided clamps with the help of which the ring groove area and / or or the free socket end area can be compressed.

According to one embodiment variant, the clamping clamp extends with its end beyond the sleeve end piece and has a retracted shelf which is intended for contact with or for pressing into the pipe to be connected. Here the protruding part of the clamp offers additional protection and can be used for the direct connection of the pipe to be connected, for which purpose profiling of the adjacent parts is possible again. In any case, the protruding part of the clamping clamp relieves the entire inner area of the sleeve if the pipe to be connected is not connected exactly coaxially, but at an angle or slightly off-axis, or if the connection is made with such a directional deviation after the connection has been made. In the case of the above-mentioned sleeve with steel straps or spaced-apart tension rings made of steel, these parts can also be integrated into a plastic-like part pulled over the sleeve, whereby a strangular seal can be made at the end of this plastic part which projects beyond the end of the sleeve by tightening the tendon provided there.

If you want a simple sleeve shape and still want to attach a locking ring or additional sealing ring, it can be provided that - the end of the clamping clamp extends beyond the sleeve end piece, has a retracted flange at the end and an opening space for one with the sleeve end the tube can be pressed on or includes with holding combs or serrations in this pushable locking ring. In most cases, the clamp will be made of a harder material than the sleeve, so that the exact extent to which the locking ring is pressed in is clearly defined. In the case of a pre-assembled clamp on the sleeve, a simple design is made possible in that the locking ring is divided according to the division of the clamp.

It has already been mentioned that it is hardly possible to increase the wall thickness compared to the wall thickness of a sleeve formed from a thick-walled pipe of relatively large diameter. Rather, it becomes simple manufacturing process, this wall thickness is usually the same or smaller than the pipe wall thickness. Under these conditions, the pressure prevailing in the line, especially in the transition area of the sleeve to the pipe and in the area in which the sleeve is not covered by the inserted pipe end, acts fully on the sleeve area, so that even in the event of pressure surges, greater loads than occur in the entire pipe or other socket area. In order to avoid weak points here, it is provided that the clamping clamp surrounding the ring groove also extends over the attachment area of the sleeve on a pipe part and forms an external reinforcement for this area in the clamping position. It can be achieved by the above-described configurations that the clamping clamp forms a two-part or multi-part protective housing for the entire socket area, which is particularly advantageous since the risk of damage to the thickening formed by the connection points when laying pipes in the ground or masonry is greatest.

Further details and advantages of the subject of the invention can be found in the description of the drawing.

The subject matter of the invention is illustrated, for example, in the drawing. 1 shows a sleeve molded onto the end of the tube in the lower half

View and in the upper half in section, FIG. 2, only showing the section, an embodiment variant, FIG. 3 in an illustration corresponding to FIG. 1, another embodiment variant and FIG. 4 another embodiment variant.

At the end of a pipe 1, for example a pressure pipe water pipe, a sleeve 2 is formed, which serves to receive a connecting pipe 3, indicated only by dash-dotted lines. The free end 4 of the sleeve 2 can, as has been indicated by dashed lines, have longitudinal slots or weak points 5 running in the longitudinal direction, which facilitate later compression of this sleeve end piece 4. Following the sleeve end piece 4, an annular groove 6 is formed. forms, which is surrounded on the outside by a bead-like shape 7 and which receives a seal 8 known per se.

In the embodiment according to FIG. 1, a two-part clamp 9 is provided, which extends over the sleeve end piece, the shape 7 and a section of the adjoining sleeve area, the inner shape of which is adapted to the outer shape of the sleeve 2 in the area mentioned and on flanges 10 in Area of the clamp halves can be clamped by screws 11, so that it compresses the sleeve 2 in its engagement area and thus also presses the seal 8 against the inserted tube 3. If different deformations of the sleeve in the engagement area of the clamp 9 are desired or necessary, one can first provide gaps between the clamp 9 and the outside of the sleeve in areas that are to be compressed less so that those areas where the clamp is already in a relaxed state abuts the sleeve 2, are compressed more when tightening the screws 11.

In the embodiment variant according to FIG. 2, a further annular groove 12 is formed in the sleeve end piece 4a, which receives a sealing or locking ring 13 which can be pressed against the inserted pipe via the clamp. Furthermore, the clamp 9a extends with its end 14 beyond the end of the sleeve and forms a retracted board intended for contact with or for pressing into the pipe 3 to be connected. Reference is made to the design options mentioned in the general description.

The embodiment according to FIG. 3 differs from that according to FIG. 1 essentially only in that an annular groove 15 which tapers conically towards the free end of the sleeve is provided in the sleeve end piece 4 and also receives a conical locking ring 16 with two retaining combs which is intended for this purpose to additionally load or prevent the inserted tube from being pulled out. The clamping clamp 9 also holds this locking ring 16 in its clamping position by compressing the sleeve end piece 4.

4, the clamp 9b, which is formed by screws 11 connected shell halves, there is a protective housing for the entire sleeve area, the left end of the clip being extended beyond the sleeve end 4b and having a rim 15 directed against the pipe 3, which includes a chamber for receiving a locking ring 16 with the sleeve end 4b. The locking ring 16 can be divided according to the division of the clamp 9b. The sleeve end 4b can have a slightly larger inside diameter compared to the outside diameter of the pipe 3. In terms of production engineering, this sleeve end 4b is preferably slightly turned while it is being clamped into a holding tool that ensures the circular shape in order to ensure an exact circular shape and exact dimensional tolerances. The transition area 18 from the pipe 1 to the sleeve 2 is also covered by the shoulder 17 of the clamp 9b and reinforced on the outside, and as can be seen, this reinforcement also extends a short distance beyond the transition area 18 on the pipe 1.

Claims

Patent claims:

1. Plastic sleeve for plastic pipes or fittings, in particular for pressure pipe water pipes, with at least one ring groove (6) for receiving a sealing ring (8) pressing against an inserted, undeformed, smooth pipe end (3), characterized by at least one sleeve (2) In the area of the ring groove (6), the clamping collar (9) enclosing the outside for the permanent radial prestressing of the sealing ring (8) by compressing the sleeve (2).

2. Socket according to claim 1, which in addition to the seal (8) receiving ring groove (6) has a further ring groove (15) for receiving a pulling out of the inserted tube, conical locking ring (16), characterized in that the clamping clamp (9a) also extends outside over the longitudinal region of the groove (15) receiving the locking ring (16) and clamps this locking ring (16) in the clamping position.

3. Socket according to claim 1, characterized in that the clamping clip (9a) over the area of the seal (8) receiving the annular groove (6) and a sleeve end piece provided at the insertion of the sleeve (4a) extends so that the clip (9a) in the tensioned position, this end piece (4a) also compresses around the connected pipe (3).

4. A sleeve according to claim 3, characterized in that the end piece (4) in its wall has longitudinal slots (5) or weak points extending in its longitudinal direction to facilitate compression.

5. A sleeve according to claim 3, characterized in that the end piece (4b) has a larger inner diameter than the inner diameter of the connected pipe (3) and can be pressed onto this pipe by reducing the diameter (9b) while reducing its diameter.

6. A sleeve according to one of claims 3 to 5, characterized in that the end region (4a) of the sleeve (2) receives an additional pressure or sealing ring (13) which can be compressed with it and pressed onto the connected pipe (3).

7. Socket according to one of claims 3 - 6, characterized in that the clamp (9a) extends with its end (14) over the sleeve end piece (4a) and a retracted, to rest on or for pressing into the pipe to be connected (3rd ) has a certain board.

8. Socket according to one of claims 3 - 6, characterized in that the clamp (9b) extends with its end over the sleeve end piece (4b), at the end has a retracted board ( ¹ 9) and with the sleeve end (4b) one for Includes tube (3) open receiving space for a locking ring (20) that can be pressed onto the tube (3) or with holding combs or serrations.

9. A sleeve according to claim 8, characterized in that the locking ring (20) is divided according to the division of the clamp (9b).

10. Socket according to one of claims 1-9, characterized in that the ring groove (6) surrounding the clamp (9b) also extends over the attachment area (18) of the sleeve on a pipe part (1) and in the clamping position an external reinforcement for this Area forms.

11. Socket according to one of claims 1-10, characterized in that the clamping clamp (9b) forms a two-part or multi-part protective housing for the entire socket area (Fig. 3).