Welding of polyethylene pipes by oneself: technology, recommendations

The advantages of flexible plastic pipes allow the expulsion of aging metal analogues. This process is especially evident in plumbing designs. Polymeric materials are easy to use and at the same time almost inferior to metal in terms of technical and operational qualities. However, along with the replacement of the material, the methods of its processing also change. A rather specific operation in terms of technical support is the welding of polyethylene pipes, during which it is necessary to use special fixation and heating devices. If this procedure is performed in a qualitative way, it is possible to obtain a sealed and resistant place of splicing of the two elements with respect to the external influences.

General information about the technology

To connect two plastic pipes, the method of docking their surfaces under the effect of heating, which is performed by a metal tool, is used. As a result of direct contact with heated surfaces, intensive heat transfer is provided. This feature distinguishes technology from heating by air. This method of heat distribution in the plastic mass acts positively in terms of forming a reliable structure and does not involve thermal stress followed by deformation of the joints. In addition, the welding of polyethylene pipes end to end allows the formation of joints, which in strength are not inferior to the whole structure. The process itself involves heating the end surfaces of the two elements to a molten state and further reducing them to a single section. But with all the external simplicity, this technology requires careful execution, which to a large extent depends on the tools used. It should be noted that modern high-tech apparatus for plastic welding minimizes the influence of the human factor, but it does not completely exclude it.

Equipment for welding of polyethylene pipes

Even small welding operations of this kind assume the use of a whole group of technical means. The basis of such equipment is a centralizer, which provides clamping of two pipes for further assembly work. Also, a special frame is used to fix the centralizer itself. To activate the work of the movable clamps, a hydraulic system is used, which works by means of a mechanical drive. However, there are different types of equipment that perform this function. On the market you can find a universal apparatus for butt welding of polyethylene pipes of different size. As a part of such devices, kits with nozzles from 20 to 75 mm in diameter are usually provided. This is the best option if you plan to perform installation activities in the home. For more complex tasks, a set of several functional parts will be required to form a single welding complex.

Centralizers for welding pipes

The first time this technology was used exclusively in work with pipes, one of which was stationary, that is, it was already part of the communication network. This made the task easier, because the accuracy of the connection increased. Problems arose in the work with two movable endings of pipes, for which the basic centralizer was introduced. This device, due to which the welding machine for welding polyethylene pipes provides high accuracy of forming the joint. It is required first to achieve alignment of the ends, and after that the operator performs their reduction. By design, the centralizer resembles a massive clamp system made of two metal parts. Although such units are to some extent related to universal equipment, they still need to be selected for pipes with standard sizes of the target range.

Hydraulic welding machines

In the process of welding, it is envisaged to exert mechanical influence on the pipes in order to move them along the axes or to each other. To perform this function, this hydraulic unit is used. Usually it forms a single complex with the centralizer, ensuring its management. In the simplest configurations, the equipment for welding polyethylene pipes performs only fixation and soldering of the elements. More complex systems require the user to control the pressure applied to the hydraulic machine, precise fitting of pipe ends and direct control of the centralizer clamps. All these functions can be placed on the hydraulic unit. Especially for the simplification of these operations, manufacturers supply equipment with ergonomic control panels, including automatic systems.

Tricers and heaters

The welding operation presages pipe preparation. In particular, with the help of the face-cutter, the edges and planes of the elements are reshaped in some way to ensure their close fit. As for the heaters, they are integrated into a complex consisting of a hydraulic machine and a centralizer. By design, this component resembles a large pancake, which is located between the ends of the two pipes, ensuring their heating. Management of this part is also implemented through a special console. If this unit for welding polyethylene pipes is used in a regular mode, then it is included in a single design with a centralizer. Usually it acts as a flip-up auxiliary device, despite the importance of the heating function. It is also worth noting that heaters must have special Teflon coatings, which allows them to be easily removed after the melting of pipes.

Preparing for welding

Work begins with the immersion of pipes in the centralizer and their subsequent fixation. It is necessary to secure the pipes securely so that they can be moved smoothly. As a rule, one part is fixed rigidly, and the other is moved by the force of the hydraulic machine. If necessary, PE pipes can be welded by themselves without a face-piece. In this case, you should initially clean the docking surfaces with a grinding tool. If there is a spindle in the presence, the stripping is performed directly on the centralizer, after which the formed chips are removed from the outside and from the inside. Then you can proceed with the control fit. It is important that the pipes match each other with minimal clearance and deviations in the planes. Small errors are compensated by welding, but in this case the plastic mass in the joint zone will be uneven.

Heating of pipes

Perhaps, this is the most important stage, since plastic heating is carried out within its framework. First of all, the heated disk should get a sufficient temperature. After that, it is located between two ends, which are pressed to provide preheating. The effort should be small, but sufficient to make the material of the two pipes melt and close together. In order to obtain high-quality welding of polyethylene pipes, it is necessary to control the thermal effect. It can be visually monitored - the optimal mode involves melting the ends, but with the condition that the structure's viscosity remains. The result of this stage should be the formation of a small roller of molten mass, which slightly extends beyond the edges of the ends.

Rearrangement

After heating the ends, it is very important to remove the hot tool in time and reconnect the surfaces to be welded. It is important that the pipes retain the overall integrity of their edges in future junctions. The maximum time period during which this action should be performed takes 25 seconds. But this is important for large pipes, whose diameter is 60-75 mm. For household PVC pipe this indicator is about 5-10 seconds. High speed of rearrangement is required for the reason that the material quickly cools down without the support of the heater. As a result, butt welding of polyethylene pipes can lose in quality because of loose connection of the ends. On the other hand, rush is not always good either. Infringements in accuracy of data of elements are not less dangerous from the point of view of formation of a qualitative seam.

Pipe sludge

The essence of the precipitation lies in the correct formation of the seam and bringing its grant to the optimum state. After the docking of the ends without the heater is completed, the stage of already full cooling of the material begins. In this period, it is also possible for the plastic mass to emerge beyond the edges - this will be the creation of a quality grant. It is desirable that the formation of a new layer of emerging plastic takes place against the background of its mixing with the grate obtained before the permutation. Thus, a deeper welding of polyethylene pipes with optimally mixed structures of the two materials will be obtained. Usually, to achieve a good result after the rearrangement, operators increase the clamping force, which tightens the end faces more tightly.

Cooling of material

The final formation of the welded joint with fixation of its structure takes place in the cooling stage. The strength in the joint zone is obtained due to the fact that the places of the pipe walls adjacent to the obtained seam increase in thickness. By the way, this means not just the formation of a reliable joint - such areas, as a rule, are more mechanically stronger than the original structure of the material. Artificially increase this figure can be due to more intensive heating, which allows the welding of polyethylene pipes within the limits of technological limitations. The same cooling should occur naturally and at room temperature. That is, to help accelerate cooling does not follow, as this can adversely affect the future quality of the seam. After complete cooling, the pipe should be removed from the welding unit, first loosening the clamping force.

Conclusion

Technologically, the process of connecting plastic pipes is much easier than welding of metal analogs. However, popular in our time, PVC materials have appeared recently, so the ways of processing them are not so common among home masters. In practice, the welding of polyethylene pipes is carried out easily and practically without investment in consumables. The main thing is to buy the appropriate equipment. To work with small diameter pipes, compact devices are offered, in which all the main functional parts are already provided. Another thing is that in everyday life the need for such operations arises quite rarely, although the quality of the result of such welding can not be repeated by any popular method.