Weld polyethylene pipes. Do-it-yourself instructions for welding polyethylene pipes. Video instruction: welding of polyethylene pipes

Hello. Today I'll tell you about how HDPE pipes are welded when building domestic and industrial pipelines. The topic is of considerable interest, as low-density polyethylene pipes are becoming more and more in demand due to affordable cost, high strength and long service life.

Welding methods

Is it possible to do high-quality welding of HDPE pipes with your own hands? It is possible, but under one condition: special equipment must be used during installation.

Welding works are carried out in two ways:

• Butt-joint - the elements to be joined are heated to the melting temperature at the ends and joined under pressure;
• An electrowelded coupling is used, which is put on the combined ends and melted.

With regard to regions with seismic activity, it is advisable to use electrofusion couplings, which provide high strength connections. Butt welding is less durable, but in this case the price of the finished result is significantly lower.

Some equipment requires relatively long power cords. Keeping a clean work environment includes keeping things out of the way and tethering as much as possible. Loose electrical cords can cause trips and falls, which is no longer safe, especially when working with 350-degree stoves and pipe razors.

Step 3: Weld Preparing Instructions

Before welding, make sure all materials and equipment are laid out and easily visible. General equipment for general weld includes. This is because there is no need to wait when the stove is needed later. Common materials for general weld include.

Let's consider each of these methods in more detail.

Method one: butt welding polyethylene pipes

Modern equipment for butt-welding HDPE pipes consists of the following elements:

• the frame (centrator) is used to fix the joined pipes in the required position;
• trimmer (trimmer) is necessary for machining butted ends;
• the heating element is used to heat the ends to the melting point;
• the hydraulic unit drives the pipes to be matched and ensures optimum joint tightness.

• We disassemble the centralizer, freeing up space for pipes (joining parts), for this we remove the fixing clips;

• We install the joined parts in the centralizer and fix them in the upper part with clamps;

We tighten the clamp screws equally on both the left and right sides. On the second clamp from the end we give more force, while on the first clamp from the end we give less force so as not to deform the pipe.

This ensures that each side has been shaved cleanly and evenly. When the razor is no longer in contact with the tube, the razor can be turned off. After the pipes have been shaved, slide them back again to make sure the razor has done its job. If the pipes are really flush, push them apart again.

Step 5: Weld Welds

It is possible that some of the welds need to be done in the field. The same welding procedures will be used, but there will be some improvements. Underfloor welds are between two pipes that are already locked in place or dug into the ground. They usually occur when another branch needs to be added, or when a stub needs to be installed. In a stub script, this is what usually happens.

• By means of the control valve, we set the required pressure of the moving part of the centralizer;

Welding pressure is determined in accordance with the table provided with the equipment. Also, the following formula can be used to determine the welding pressure.

• We clean the surface of the ends from dirt and dust using special wipes or lint-free rags and alcohol as a solvent;

• We install the trimmer between the joined parts on the bed;
• We turn on the hydraulics and shift the joined elements, and then turn on the trimmer;
• We dismantle the centralizer and remove the remnants of plastic chips from the pipes;

• We check the joined parts for alignment;

• We clean the ends of fat;

• We install a heating element on the frame;
• We set on the timer the time and temperature necessary for melting the polyethylene walls;

For low pressure polyethylene, the melting point is at least +220°C.

IN daytime this is not possible in such places because traffic and life in the city will be too much affected. That's why we work at night. There is only one short window available: from midnight to five o'clock. The bubble is kind of steady balloon, which is inserted into the tube and inflated until it completely closes the tube so that the gas cannot escape. A specially installed emergency line provides gas supply during the daytime during construction work.

It must be removed at night for work to continue. However, you don't see sparks because the polyethylene pipes are butted together. The men heat the ends of the pipes with a 220-degree hot device called a mirror and join them together. Meanwhile, two other teams are preparing crossings in open trenches. When it comes to energy, safety is written 360° - both for the safety of our customers and our employees. This good feeling. Energy 360° meets the highest safety standards.

• We turn on the hydraulics and bring the joined elements to the heater under pressure;

• We start heating, which will stop after the timer runs out;
• After the timer has beeped, turn off the pressure and remove the heating element;
• Again we bring the joined ends under pressure to obtain a strong and neat seam;

• We start the timer to cool the polyethylene;

The cooling of polyethylene for the quality of the seam is no less important than the welding itself. Therefore, we stand for cooling for at least 7 minutes and at this time we do not disturb either the connection or the centralizer.

• After the sound signal, turn off the pressure, disassemble the equipment and release the welded structure.

Method two: butt welding of curved sections of the pipeline with an extruder

Now we know how to weld polyethylene pipes end-to-end on straight routes. But what to do if you need to weld not a straight section of the route, but, for example, make a bend at an angle of 45 degrees? In this case, special equipment is used for welding HDPE pipes - an extruder.

Instructions for conducting welding work next.

Let's take a closer look at the steps listed in the diagram.

• Through miter saw we cut the ends of the pipes at the required angle;

• We remove the chips and cut off the burrs, after which we wipe the surfaces to be joined with a rag soaked in alcohol.

• The parts to be joined are placed on flat surface, join each other at the right angle and are held manually;

• On the extruder, we set the melting temperature of the granules (+220 ° C);

• Next, with an extruder, we make tacks at the junction of pipes;

• After the potholders are made, we wait 5-7 minutes for the plastic to cool;

• We apply plastic around the entire circumference of the parts to be welded;

• After the plastic is applied, we leave the structure to cool for 7 minutes, after which the welding is considered completed.

If, when applying plastic from an extruder, the seam is not very neat, it can be trimmed with a knife at the end of welding.

A special pressure chamber sealing system allows you to move the tube without pressing it into its original position. The pipe is no longer stressed and there is no risk of breakage. After installation, the pipe must be resealed to check the tightness! On request, test sockets, threaded sockets or flange sockets can be welded into the steel housing. Sealing bridges, depending on the nominal diameter of the pipe, allow diameter deviations of up to 30 mm. Maximum operating pressure 16 bar Angular deflection max. 4 rec.

Now a few words about the strength of the weld. In terms of the experiment, after the plastic cooled down, the deformation of the assembled branch was performed.

The installer pressed on the seam area with his weight until the cross section of the round pipes became oval. Of course, similar experiments with butt-welded pipes by heating the ends will demonstrate a lower strength of the seam.

Method three: electrofusion welding

A review of methods for connecting polyethylene pipes would be incomplete without the use of electrofusion couplings. Today, this method is becoming more widespread due to the high strength and durability of the finished result.

The method is applicable both in the construction of pipelines in enclosed spaces, and when working in the field. A significant disadvantage of this method is the high price of couplings. On the other hand, such a cost is justified by the high performance of the connection.

Instructions for making connections using an electric coupling are in the following table.

Let's consider the above points in more detail.

• The butted ends are cut with a special pipe cutter in order to obtain optimal alignment during docking;

• Using a manual scraper, remove the oxide layer from the surface adjacent to the docking area (about 20 cm from the end);

• We remove the formed chips using the same scraper;

• outer surface of pipes and inner surface couplings are degreased special napkins or a lint-free cloth soaked in alcohol;

• We mark the pipes according to the size of the coupling for easier positioning in the centralizer;

• According to the marks made, we fasten the pipes and the coupling in the centralizer;

The prefabricated structure must be fixed, but not deformed. So that the round section of the pipes does not become oval, do not overtighten the clamps.

Barcode reading

• We turn on the device and read the barcode printed on the clutch body;

Most modern welding machines operate in semi-automatic mode. The heating and cooling time of the coupling is set in the process of reading the data encrypted in the barcode. Without reading the code, the machine will not start welding.

• After the code is read, we start the welding process, after which the device notifies with a sound signal;
• At the end of the welding process, we detect 7 minutes, after which the cooling of the polyethylene can be considered completed;

• We disassemble the clamps on the centralizer and release the equipment from under the soldering point.

This manual can be used as a guide for a superficial acquaintance with HDPE pipe welding processors. For best results, follow the manufacturer's instructions that come with both the machine and the coupler.

Output

So, now you know how to combine polyethylene pipes into a single whole. Any questions left? Ask them in the comments to the text. In addition, I recommend watching the video in this article.

July 31, 2016

If you want to express gratitude, add a clarification or objection, ask the author something - add a comment or say thanks!

The appearance of polyethylene pipes has turned the laborious work of installing communications into an exciting game. After all, the design is so easy and quick to assemble that it is difficult to call this process work. Difficulties may lie in wait for you except at the stage of connecting elements. Let's talk about this mounting block. So, how is the welding of polyethylene pipes done, and is it possible to do everything yourself?

Polyethylene structures

In order for you to better understand the instructions for welding polyethylene pipes, you should get to know this material better, find out its advantages and disadvantages.

Polyethylene pipes are the "descendants" of ordinary plastic pipes, their latest generation, the most perfect and most versatile. Now such structures are used everywhere - for various needs: heating, water supply, waste disposal, and so on. No wonder, because the latest generation of plastic works flawlessly and "lives" to an advanced age - half a century. This material in its characteristics is much superior to the familiar metal, which was once the most reliable for laying communications. Therefore, homeowners everywhere change iron for plastic - no matter how provocative it may sound, but the latter is more reliable.

The variety of polyethylene products is amazing

Check out the list of its benefits:

• a light weight;
• ease of installation;
• low price;
• versatility of application;
• the ability to install in any weather;
• low volume of waste;
• no effect of corrosion;
• maintaining design flexibility;
• high strength seams;
• lack of lime deposits inside the system;
• perfect smoothness of products;
• resistance to aggressive substances;
• lack of condensate;
• acoustic isolation;
• attractive appearance.

If we talk about the disadvantages of this type of construction, then they appear only if the technical chart for welding polyethylene pipes is violated. So remember carefully how to do everything right.

Do you want to do everything yourself? So get ready to remember

Connection types

In order to turn a set of polyethylene products into a system, you need to get acquainted with the types of connections and choose the most optimal one - suitable for your situation.

So, the methods of fastening pipes are divided into the following:

1. Mechanical connection. The easiest, but not universal (suitable for attaching internal fragments of the water pipe) assembly method. For work, fittings and appropriate tools will be required. Such a connection can be disassembled and reassembled at any time, which is very convenient for repairs or inspection of structures.
2. Welding. This type of fastening is more laborious, but also more reliable. With the help of this technique, it is possible to mount communications, both by the method of trench laying, and by the trenchless method. Modern technology welding of polyethylene pipes allows you to maintain the flexibility and strength of products. In practice, two types of connection are used:
   • electrofusion welding;
   • butt welding.

It's important to know! For welding to be of the highest quality, buy products from the same manufacturer, and pipes produced in the same batch. If it does not work out, then sort the elements of different batches and connect them together.

Make sure that the cutting of the elements occurs strictly at right angles.

Welding instruction

If you chose polyethylene pipes, you acted wisely, but now they still need to be installed correctly. Let's learn

Basic Rules

Regardless of which technology you choose - electrofusion or butt welding of polyethylene pipes, you must adhere to such important principles:

1. The elements to be joined must be compatible (both in composition and in physical parameters).
2. Butt welding of polyethylene pipes can only be carried out if the parts have the same diameter and equal wall thickness.
3. Edges should be thoroughly cleaned and degreased.
4. The ends of the structures that are not involved in the connection process must be closed with plugs in order to avoid exposure to cold air, which negatively affects the process.
5. During work, it is necessary to minimize the impact of the external environment, namely:
   • in the heat, do not allow sunlight to reach the connection area;
   • in windy weather, create a barrier to gusts of air;
   • in cold weather, it is recommended to heat the room for work.

1. During welding and cooling of the structure, exclude mechanical impact on the system.

And now let's consider in detail what the technology of welding polyethylene pipes is butt-welding and using the electrofusion method.

Worth paying attention! Before starting work, test the structures for ellipse. Do not use defective products, otherwise you will ruin all the details.

Photofragment of the electrofusion technique: attached heaters

Electrofusion connection

This type of welding, also called thermistor welding, is used to fasten elements of different wall thicknesses and diameters, as well as to install non-pressure pipelines - drainage installations, gravity sewers, etc.

To connect using this technology, you will need special - electrofusion fittings. Now remember the order of work.

1. Design the system.
2. Calculate the required number of pipes and other parts.
3. Make a purchase.
4. Cut the structure into pieces of the length suggested by the plan. Make sure that the cut is straight, avoid the flow of molten material into the system.
5. Prepare and clean parts, including couplings. It will not be superfluous to degrease the surface of the elements with alcohol, applying it to a piece of rag.
6. If the surface of the elements is oxidized, remove the excess with a special scraper.
7. Fasten the elements in the positioner, mindful of alignment.
8. Wrap the joint with adhesive tape to prevent dust from entering.
9. Close the open ends of the structures with plugs.
10. Apply voltage to the clutch terminals.
11. Wait until the elements, having warmed up, are held together.

Thermistor welding of polyethylene pipes should be carried out only if the connected elements are immovable. In the same position, the structure must remain until the seam has completely cooled.

This is what a splice setup looks like

Butt welding

The technology and parameters of butt welding of polyethylene pipes are more interesting, since the elements are connected at the molecular level, forming a stronger seam. This method is used for mounting elements having a diameter of 50 mm and a wall thickness of 5 mm.

At this method the edges of the products are heated with a special heating device, and then melted and in this state are joined, forming a single whole and a flawless seam.

The procedure for this type of welding up to point No. 7 is identical to the previous connection option (except that couplings are not required for work).

Table for determining the heating and cooling time of the elements to be welded

And then it differs and goes according to this “scenario”:

• insert the ends of the elements into the apparatus so that the heating plate is between them;
• press the edges against the plate and do not change the pressing pressure until the melting process;
• heat the elements, adhering to the norms (the table below for welding polyethylene pipes will help you with this);
• remove the plate and dock the ends, exerting uniform pressure on them;
• holding the knot, wait for the polyethylene to cool.

Worth paying attention! In order for butt fastening to be done efficiently and quickly, use devices with a mechanical or hydraulic drive.

Video instruction: welding of polyethylene pipes

Welding polyethylene pipes is a responsible but exciting process that you are now trained in.