DE1115440B - Method and device for producing socket connections for plastic pipes - Google Patents

Description

The invention relates to a method for producing socket connections for pipes thermoplastics, in particular made of polyethylenes, and a device for exercising of the procedure.

It is known to use plastic pipes, e.g. B. those made of polyvinyl chloride, by welding seams with addition of material connect to. In these procedures, it is common to use turning, milling, grinding, or filing Rasping prepared butt joints, mainly in V-shaped seams, with the help of welding wires or welding strips using a hot air device. This for hard polyvinyl chloride pipes best practice - in general, skilled welders will use a figure of merit of 0.6 achieved - but cannot easily be transferred to pipes made of other plastics. Particularly In the case of pipes made of polyethylene, the unavoidable thermal effect when welding small cross-sections Degradation of the plastic has a detrimental effect on the strength properties of the seam.

For the connection of plastic pipes, in particular pipes made of hard polyvinyl chloride, is further known as heating element welding. The ends of the are cut off at right angles to the longitudinal axis Pipes heated to welding temperature by means of a heating plate and pressed together welded. The quality of such welded joints cannot be expressed numerically, because generally recognized test methods do not yet exist. In any case, this is what the application delivers Procedure on other plastic pipes, especially on polyethylene pipes, connections inadequate Strength. In addition, the free passage of the tubes is reduced by the inner bead; In the case of small pipe cross-sections, this can lead to blockages.

It is also known to place plastic pipes in between of a metal ring or other metallic molded parts and the welding to be carried out by the formation of eddy currents in the high-frequency field. The metallic inlays remain part of the connection, it is therefore used for many purposes, especially many pipelines, not suitable.

In the metal industry, it is common to weld socket joints by welding the socket edge with the spigot end or, as with the so-called Iraq socket connection, the To put together ends of the pipes widened to form sockets via a nipple and the socket end edges to be welded using a V-seam. Both Ver Method and Apparatus

for making socket connections

for plastic pipes

Applicant:

Farbwerke Hoechst Aktiengesellschaft
ίο formerly Master Lucius & Brüning,
Frankfurt / M., Brüningstr. 45

Dr. Emil Rottner, Frankfurt / M.-Unterliederbach,
and Wilhelm Muth, Frankfurt / M.-Höchst,
have been named as inventors

driving can only be transferred to the connection of plastic pipes if there is a reduction in strength can be accepted that some plastics as a result of the thermal Degradation occur when making the seams.

It is also already known to connect two pipe ends by having one pipe end through Heating is softened and pushed over the other end of the pipe, whereby for sealing an adhesive is expediently applied. However, the heated end of the pipe is only used for this purpose Purpose of softening one end of the pipe so that it is expanded and pushed over the other end of the pipe can be, since a gluing of polyethylene pipes, for example, not at all is possible.

Another known method relates to the bending of porous, from in organic Solvent-soluble, swelling or softening synthetic resins existing structures, such as. B. Filter plates, diaphragms, etc., but is familiar with the processing of thermoplastics, especially polyethylene, not to be compared as it is not porous, in organic solvents soluble, swelling or emollient materials.

There have also been some devices for connecting individual parts made of plastics or Production of pipe connections known. So was z. B. a hand-held device for connecting several Items suggested by gluing, with its

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Help plastics, for example from phenölplasti- by creating a heater that z. B. with the help of Schem plastic, tempered in a warm state under pressure of electrical resistors, take place,
In some cases, it is also advantageous to connect the connecting parts by immersing them in hot liquids, and to bring them to welding temperature; in this device for pipe connections, especially for cases must ζ. Β. Covered sleeve pipes with a rubber seal, each with one on, ensure that only the surfaces to be welded with the sleeve and the pipe end come into contact with the liquid to be detachably fastened.
Pipe clamp suggested. This connection is used for some pipe materials, e.g. B. with those, but less for the exact centering of those that tend to oxidize in the heat, it is furthermore advisable to carry out the heating and welding in the connecting parts, especially in a protective gas atmosphere, rather than to facilitate the assembly ,
this requires a greater expenditure of force for large pipes. The method according to the invention may also be required. can still be designed in such a way that sleeve

There are also a number of other connecting or inserting parts, or both, cutting or cutting or devices are known which deform the connection loses in order to oppose the plug-in part to give that of pipes made of thermoplastic material to the assigned sleeve excess. the by welding to the object, which, however, cause excessive dimensions of the plug-in part when they come together not to the desired, flawless socket steeken with the socket the displacement of a Connections for pipes made of thermoplastic 20 My part of the softened mass, and it emerges lead substances. immediately in front of and just behind the welding point

There has now been a method of making small beads. The formation of the visible socket connections for pipes made of thermoplastic baten already in the production of the weldable plastics, in particular from polyethylenes, allows conclusions to be drawn as to their nature, insofar as welding, which has the disadvantages of being 25 as one pronounced, evenly shaped Makennen working methods avoided. This method of material stowage, as a rule, a successful weld is characterized according to the invention in that the high quality level corresponds to
In Figs. 2 and 6, the position and design of the plug-in part before plugging together up to one of the beads 1, using the example of a type of weld, make up only a fraction of the pipe wall thickness - 30 of the Schifcbermuffenverbiüdung (Fig. 2) and The remaining parts of the pipe (Fig. 6) are shown at the two depths by brief heating in a doughy-liquid game of a conical socket connection Used in a wide variety of socket joints, in many cases it has been shown that what is particularly surprising is that one is even with only superficial jointing, apart from the heating to bring about this doughy-liquid state required device, o Without a special connection the parts are already sufficiently connected to produce aids at each assembly area. Even that meets the requirements of practice. the hand inexperienced in welding plastics can, however, if necessary, the softening 40 worker can easily see how long he has carried out so far that it reaches about half of the surfaces to be connected of the selected heat of the pipe wall. source must expose so that only so much of the art

With the material material proposed according to the invention, it changes into a doughy-liquid state,

a welding of the socket with the just required to achieve the welding

Inserted part achieved, which is borrowed a high grade of 45.

shows. To heat the plug-in part or the socket,

The new method can be used in the same way - it is easier to serve yourself with the benefit of a couple

bar for connections according to Fig. 1, in def a nor- pliers, in which the jaws of the pliers are divided

male socket connection in an example execution heating ring or is designed as a split mandrel.

tion is shown, as for pipeline components, the 50 such devices are shown in Figs. 10 and 11 in

in the manner of the double embodiment shown in Fig. 2. Ring part 1

Socket connections are to be welded. and mandrel part 3 are in the forge fire, with the help

If there are two socket end pieces, the connection of a burner or in a bath can be heated and

connection with the help of a nipple according to Fig. 3, then applied to the surfaces to be heated,

follow. Further reductions and reductions can be made. The mandrel and ring parts or

branches in the simplest way, e.g. B. in the pliers jaws with electrical resistance heating

Fig. 4 and 5, can be made. be equipped. In any case, that makes it easier

Using the same procedure, conical pliers shape can be used to place the radiators and

Socket connections, e.g. B. in the way it prevents deformation of the socket connection parts

Figs. 6, 7 and 8 are reproduced, even if inadvertently longer or stronger

the; also spherical socket and plug-in parts, for which heating is necessary. The pliers can too

An example is given in Fig. 9, can easily be designed so that the dome or ring parts for

can be welded together. different sleeve types or sleeve sizes

The heating of those to be welded together are to be changed.

Surfaces can be used here by means of open flames, for. B. 65 The welding method according to the invention can

with the help of ring burners, by means of a hot continue to be facilitated by the fact that the to

Gas or air flow, e.g. B. using a connecting tube in the common longitudinal axis

Hot air welding device of a known type, or also centered and clamped in this displaceably

the. This happens e.g. B. for a socket connection, which is shown in Fig. 12 according to the principle.

Pipe part 4 is through the clamping device 7 and pipe part 5 through the clamping device 8 in the common Centered longitudinal axis. Through a transmission that z. B. essentially from the racks 9 and 10 and consists of a gear 11, the pipe ends are displaceable in the pipe axis. The leadership happens on a bed in a known manner. The sleeve 6 is clamped in a clamping device 12, which is attached to a lever 13 and can be pivoted about an axis 14. The lever 13 is locked in one end position so that the socket axis and the pipe axis coincide. After heating of the contact surfaces, the socket is swiveled into the pipe axis and the pipes through Rotation of the gear, which can be done with the help of a crank, against each other and introduced into the sleeve. After opening the clamping devices 7, 8 and 12, the finished pipe connection can be removed will.

After the sleeve clamping part has been extended, the same device can also be used to make the connections according to Fig. 1, 4, 6 and 7 can be used.

In the case of pipe materials that tend to oxidize when exposed to heat and, as a result, carry out the Require heating and welding under protective gas, it is advisable to use the device in Fig. 12 is shown to encapsulate. It is advantageous to use a transparent housing that also includes the heating devices.

Claims (10)

PATENT CLAIMS: 1. A method for producing socket connections for pipes made of thermoplastics, in particular made of polyethylene, by welding, characterized in that the surfaces to be connected to each other of the socket and plug-in part before being plugged together to a depth which is only a fraction of the pipe wall thickness by brief heating in pasty-liquid state, but the remaining parts of the pipe wall thickness are not converted into the range of thermoplastic deformability. 2. The method according to claim 1, characterized in that the to be combined 35 40 welding surfaces can be heated by means of an open flame. 3. The method according to claim 1, characterized in that the to be welded together Surfaces are heated by means of a hot gas stream. 4. The method according to claim 1, characterized in that the to be welded together Surfaces can be heated by applying a heater. 5. The method according to claim 1 to 4, characterized in that heating and welding be carried out in a protective gas atmosphere. 6. The method according to claim 1 to 5, characterized in that the socket or plug-in part, or both, by cutting or non-cutting, are deformed to the insertion part compared to the associated To give socket excess. 7. Device for heating the male part in the method according to claims 1, 4 and 6, consisting of a pair of pliers, characterized in that the jaw of the pliers is a split heating ring is trained. 8. Device for heating the sleeve in the method according to claims 1, 4 and 6, consisting from a pair of pliers, characterized in that the jaws of the pliers are designed as a split mandrel is. 9. Apparatus according to claim ?, characterized in that the heating ring and heating mandrel with are equipped with electrical resistance heating. 10. Device for producing a welded joint according to claims 1 to 4 and 6, characterized by a centering jig (7, 8) for the insert parts (4 and 5) and a clamping device for the socket which can be pivoted into the pipe axis (12). Considered publications:
German patents No. 717 789, 716 120,
338; British Patent No. 573 071;
Swiss Patent No. 278 090;
U.S. Patent No. 2,384,014;
VDI guidelines for the design and processing of plastic pipelines made of polyvinyl chloride VDI 2010, April 1944. 1 sheet of drawings © 109 709/377 10.61