Electrofusion welding of HDPE pipes. HDPE pipe welding machines

Or main sewage cannot be performed using a single piece of material. So far, many methods have been developed by which the connection of individual segments is made. The most advanced is electrofusion pipe welding.

The essence of the method lies in the fact that the connecting fitting has an electric spiral. It can be fully open, partially recessed or hidden. The heating element has two outward-facing contacts to which the welding machine is connected. For a given period of time, the specified voltage value is applied. The inner part of the connector and the inserted pipe section become liquid under the action of temperature. The outer wall does not warm up to such an extent and retains elasticity, which causes the substance to move downward, resulting in a monolithic structure.

Couplings are made of three types of plastic: polyethylene, polypropylene, polybutene. For the installation of gas pipelines, only the first option is usually used.

Note! The fittings are labeled, which informs the operator about what voltage and for what period to apply. The cooling time of the finished joint is also indicated. Additionally, the design provides for special indicators that signal the completed process.

This technological method has many positive aspects:

During welding, the inner diameter of the pipes does not decrease. This means that it can be used not only in cases where there is a constant pressure head in the system. Drainage and storm systems will be no exception.
Thanks to a well-thought-out instrumental base, the human factor is minimized when performing all the required operations.
This method is more acceptable when it is necessary to bond two large diameter pipes.
Electrofusion welding will be indispensable when repair of the main line is required, and it is not possible to move pipes in a horizontal plane.
An obstacle to articulation will also not be the case when both or one of the pipes is reinforced with reinforcing inclusions. With butt welding, there is no guarantee of such a strength of the seam.
XLPE pipes are usually joined mechanically. ZN welding makes it possible to act on molecular bonds, providing a high-quality seam.
The assembly of a pipeline with multiple branches can be carried out on site, without the need for pre-connection and installation of a ready-made structure.
Saving electricity compared to other types.
The advantage of welding products from different grades of polyethylene, as well as different diameters.

In order for the whole process to go smoothly, you must have a specific tool with you:

Welding machine. A unique unit has been developed for this type of welding. It is based on semiconductor technology, therefore it consumes an order of magnitude less electricity than its other counterparts. Typically, for such units, the maximum and minimum welded diameters are indicated. A barcode scanner is provided that automatically enters data on a specific type of connection, this can also be done manually. Data on each passed joint is stored in memory so that the operator or control group can receive information. There may be a built-in serial or USB port, the latter can be connected to a flash drive to transfer settings or data. The front panel usually contains a display that shows the current parameters. Complete with some units are tips of various sections.
Positioner. A small metal device in the form of a bar that has several clamps. This tool makes it possible to arrange nozzles in the same plane for welding. It is also designed to correct ovality. A separate clamp can also be used for these purposes.
Pipe cutter. Usually use disk. It is he who makes it possible to perform an even cut, which is a requirement.
Scraper. Small handle with a blade. It can also be a device with several modules. One of them is placed in the pipe, the second, on which the cutting head is located, is connected and, during rotation, removes the top layer. This procedure is necessary not to create a rough surface, but to remove the oxidized part of the pipe.
Roulette or ruler.
Purifier. It is necessary to remove dirt and grease. It is necessary to use a specially designed for a particular type of pipe. Do not use regular alcohol or acetone.
Marker. A waterproof white or bright color is used to apply not only markings, but also some data to the soldering site.

Note! For the saddle tie-in, a special drill is additionally used, as well as a hex key and a screwdriver for the clamps.

The soldering process is not very complicated, but it requires a certain accuracy, attention and perseverance.

If there is time before the work is done, then it is advisable to straighten the pipe a day before unwinding it from the bay, this will help to partially correct the ovality.
The first thing to do is cut the end of the pipe. For these purposes, it is possible, but undesirable, to use a hacksaw. The end is rough. Use a disc pipe cutter, it will ensure the correct plane.
Next is the markup. It is necessary to draw a line to which the fitting will be put on. From it, make a margin of another 1-2 cm and designate.
Use a scraper or mechanical oxide cleaner to remove the top layer. For pipes whose diameter does not exceed 63 mm, it is 0.1 mm. If the outer diameter is larger, then you need to remove 0.2 mm.
The pipe is now treated with solvent and placed in the positioner. It must be well fixed and correct ovality. The fitting must not be subjected to a fracture load. The positioner must compensate for it.
A sleeve is put on (it must also be treated with a solution from the inside). If the pipe diameter is very large, then the coupling is stretched to its full size. The second branch pipe is brought in and the fitting is knocked down to half its depth. The embedded spiral must be located on the pipe section with its entire area in order to ensure the correct alloy.
After connecting the two pipes, the welding machine is connected. The required parameters are read by the scanner or entered manually. The process starts. It is important to remember that a complete cycle also includes the cooling time. If you remove the clamp ahead of time, then the tightness will be broken.
When all tasks are completed, the time and date, as well as the operator, are stamped on the connection.
Mounting saddle tie-in has a similar algorithm. Cleaning is carried out at the installation site, but not along the entire circumference, but only the soldering area, which will be covered by the spiral. After stripping, a saddle is put on and firmly clamped. Welding is in progress. Further, with the help of an additional tool, a cut is performed. With the help of a plug, the technological hole is closed and a mark is applied.

Note! Do not use sandpaper or non-designated scrapers to remove oxide. You will just scratch the surface, but will not achieve the desired result.

In some cases, the connection is depressurized. This can be detected already at the completion of the complete installation. This happens for the following reasons:

The operator did not compensate for ovality. This can result in the melted plastic not filling the entire space.
Cleaning was not done with a scraper. The result will be that the sleeve and pipe do not form a monolithic weld.
The pipe was at an angle to the fitting. The result will be the leakage of liquid plastic.
The fitting was not fully fitted. The embedded coil will not melt enough of the mating surface.
Degreasing was not carried out or after it, the cleaning site was touched with hands. The connection will not be sealed.

This instruction also applies to connecting HDPE pipes. This method is much better than mechanical clamp fittings, which cannot provide a perfect seal.

Video

The provided video materials show the technological process of electrofusion welding of pipes:

Electrofusion welding is one of the main types polyethylene pipe connections(HDPE), a feature of which is the use of a special heating element - an electrical coupling. This welding method is more expensive than butt welding, but sometimes this method is indispensable. In this article, we will consider in which cases electrofusion welding is used and what is the principle of its operation.

Today electrofusion welding HDPE used for pipes of different wall thicknesses and different diameters, when installing a non-pressure pipeline - drainage systems and gravity sewerage, tie-in into an existing pipeline and repairing existing pipelines. When connecting with an electric coupling, the speed of work is very high and little free space is required.

Usually, electrofusion welding of polyethylene pipes carried out using special equipment equipped with microprocessor control. Due to this, sleeve welding provides control of process parameters, automatic regulation of welding time, which depends on the parameters of the shaped element and air temperature.

Technology of socket welding of polyethylene pipes

Welding polyethylene pipes using this welding method places special demands on the work. Before starting welding, it is necessary to clean the surfaces to be welded, making sure that no dirt or oxide film remains. In the case of welding a branch saddle, correctly selected clamps must be used. When electrofusion welding is carried out, the pipe and the fitting must remain absolutely immobile, not only during the connection, but also during the cooling process.

The process of welding pipes using embedded electric couplings is carried out in the following sequence:

the ends of the connected polyethylene pipes must be cleaned of dirt and degreased.
the electric coupling is put on the end of one of the pipes, until the end of the coupling and the HDPE pipe are aligned. If necessary, the pipe is clamped in the positioner. The second pipe is aligned with the first "end to end", after which the coupling is pushed in the opposite direction by 1/2 of the length of the coupling.
wires from the welding machine are connected to the terminals of the electrical coupling.
the heating process of the electric coupling is started in the "automatic" mode. Pipe welding is complete when molten polyethylene emerges from the test ports of the fitting.
the last stage of the process is the natural cooling of the welded assembly to complete immobility.

The main advantages of electrofusion welding:

Universal application regarding polyethylene and its wall thickness. The properties of molten polyethylene make it possible to use this method to connect pipes with different diameters.
Practicality and ease of installation. To weld HDPE with this method, it is enough to simply bring the ends of the pipes together and connect them with a heating element, and then heat them up by simply applying electric current to the coupling terminals. After that, the process will take place offline.
Reliability. A distinctive feature of this method is the reliability and durability of the final result. The materials at the joints penetrate each other, so the density of the seam is the same as that of the rest of the pipe.
Economical and efficient application. Machines for electrofusion welding are compact in size, light weight and relatively low power consumption.

Based on the foregoing, we can conclude that electrofusion welding has established itself as a reliable, economical and convenient technology for connecting pipelines in gas and water supply, as well as for sewage. A pipeline assembled from polyethylene pipes with a high-quality welding process will last for several decades without requiring additional maintenance and repair. However, specialists from the Volzhanin plant note that a mandatory part of the procedure welding of polyethylene pipes is the quality control of the connections made. It is possible to continue processing pipes in the future only after inspecting all the connections made. The seams made must exactly comply with the established technical requirements, only then the connection can be confidently recognized as quality.

If you plan to connect pipes with VOLZHANIN devices and you have any questions while using the equipment, you can get round-the-clock technical support by calling the hotline 8-800-200-17-45 (toll-free within Russia).

Installation of the sewer system is carried out using special pipelines, which can be made of plastic, ceramic or metal. As with many plastic elbows, HDPE pipes can be welded with heat tools or cold-pressed sleeves.

Installation options

Technologically, it is possible to connect HDPE pipes without welding or using a special welding machine. Both methods have their advantages and disadvantages, consider the advantages of each method of fastening.

Cold welding or pressing is the simplest option, it is a very cheap and accessible method, which is carried out through the use of special couplings. This technology is mainly used for pipelines of large diameters - from 20 to 300 mm. Cold weld compression fittings have the following pros:

Ease of use;
Large selection of sizes;
Providing a tight connection with high sealing performance.

But pressing is mainly used only for fixing non-pressure water connections. Plastic pipes have relatively little rigidity, due to which, with strong internal pressure, the seam can simply disperse, unlike welding fasteners, which are considered “dead”.

Classical welding, or, as they say, soldering of HDPE pipes can be performed using the electrofusion method, or a specific welding machine is used for its implementation. Electric couplings are a very practical method of connecting metal gas pipes, as well as plastic water supply communications. A coupling of a certain diameter is installed on the free section of the outlet, after which the second pipe segment is pushed into it. Such soldering is also called butt soldering, due to the fact that in order to achieve the most durable and tight fastening, it is necessary to install parts of the pipeline very tightly with a minimum gap.

Photo - fittings

It is convenient to work with couplings on large diameters, but this is not the best solution for taps under the washbasin or heating communications. But on the other hand, HDPE flange connections, if necessary, can be removed and urgent repairs can be made.

Photo - butt

Manual soldering of pipes is done by using a soldering iron, it requires special equipment for organizing HDPE connections. For such work, the temperature of the heating elements and the exposure time are very important. Please note that these parameters are selected based on the technical characteristics of the soldering device, the thickness of the HDPE and the diameter of the taps.

Advantages of the technique:

This is the most durable and reliable option. Due to the implementation of one-piece fastening, it can be used both for pressure-type HDN and for non-pressure connections of shut-off valves;
Flanged connections can be used both when fixing an external system, and when installing internal main pipes;
No prior training required. It is quite enough to watch the video and read the SNiP standards, which indicate in detail how to trim, install and fasten.

But the disadvantages include the fact that the connection, if necessary, cannot be removed. Despite all the advantages of this, sometimes it is necessary to open and clean the pipe.

Socket installation

It should be noted that in domestic documents you will not find any standards for socket soldering. It is only described in European standards DVS 2207-15. Step-by-step instruction, how to weld HDPE pipes with couplings:

After finishing heating and welding, remove the coupling and fix the pipes on a solid surface.

Flanges are even easier to work with. They are threaded connections for installation. Accordingly, a thread is cut out at one end of the communication, into which the element is screwed, and a pipe is already put on it. The junction is heated with a hairdryer or a muff.

Photo - flange pnd

Extruder welding

It is a little more difficult to work with a hand-held hairdryer or soldering iron, because you need to additionally control not only the warm-up time, but also your own movements. If the welding is not carried out correctly, the integrity of the HDPE pipes can be violated or the seam can be spoiled.

Photo - professional inverter

Step-by-step instructions for welding with an inverter:

It is very important not to overexpose the fastening, if the welding is too tightened, then the HDPE will become very thin or there will be an influx of polyethylene on the inner diameter. To control this moment, a special table is used:

Outer diameter, mm	Weld seam, mm	Heating, sec	Connection, sec	Cooling, sec
20	14	6	4	2
25	16	7	4	2
32	18	8	6	4
40	20	12	6	4
50	23	18	6	4
63	26	24	8	6
75	28	30	10	8
90	30	40	11	8
110	32	50	12	8

Video: Electrofusion welding of HDPE pipes

Price overview

You can buy a machine for welding HDPE pipes in any city, if the price is not suitable, now many companies provide equipment rental. Consider the cost of the V-Weld R063 model:

City	Price, u. e.
Voronezh	28
Yekaterinburg	28
Kazan	30
Krasnodar	28
Moscow	33
Novosibirsk	30
St. Petersburg	33

With a diameter of 20 to 1200 mm, they are widely used due to their advantages and ease of installation. They are used for laying gas and water pipes, internal, external, storm sewers. Depending on the goals, polyethylene pipes can be pressure or non-pressure. The latter are just used for sewer systems.

Polyethylene pipes can be connected in three ways, one of which is detachable (connection by means of flanges and fittings), while the other two are welded one-piece (butt welding with special equipment or using electric couplings). The welded joint is the most durable, the seams are sealed and resistant to chemically aggressive environments.

Preparatory process before welding HDPE pipes

Regardless of the type of HDPE pipe welding, a number of preparatory measures should be taken before work. Namely:

purchase and bring to the work site the pipes themselves and fasteners (straight fittings, angle fittings, tees and other connecting elements), clamps and reducing inserts corresponding to the diameter of the pipes to be welded;
to equip and free from foreign objects the working platform on which the welding equipment will be placed;
mechanically process the ends of HDPE pipes and all fittings.

Welding equipment before work should be carefully checked for serviceability and performance. The procedure for preparing the equipment is as follows:

the nodes of the welding machine are visually inspected, the ground electrodes and electrical wires are checked for serviceability, the trimmer knives are checked for the degree of sharpening;
then prepare the generator, filling it with fuel and conducting a test run;
equipment parts (scraper, trimmer, heater) before work are cleaned of existing contaminants and traces of adhering polyethylene, then all surfaces are degreased with a solvent;
on the hydraulic system of welding equipment, it is imperative to check the presence of oil and its level, conduct a test for the operability of the movable clamp, after which all rubbing parts of the equipment are lubricated with special compounds;
check all available control and measuring devices.

If we compare electrofusion and butt welding, then the first is less economically profitable, but it is very convenient to produce it in cases where work is done in cramped circumstances with a minimum amount of working space. Electrofusion welding is often used to repair HDPE pipes (especially for pipes up to 160 mm in diameter) and to install a branch in an existing pipeline. Welded seams after high-quality work can withstand pressure up to 16 atmospheres.

Principle of electrofusion welding method

The electrocoupling is a shaped piece made of polyethylene with electric spirals implanted into the coupling body. Couplings are produced for pipes of various diameters and are calibrated with a barcode, which indicates the temperature conditions, the duration of heating and other information for work. If straight-line welding of HDPE pipes is performed, then the coupling is used in a simple form; for the installation of other structures, there are electrofusion tees, saddle bends and other parts made of polyethylene with similar electrospirals.

The principle is as follows: after applying electric current to the coupling spiral, the temperature of the nearby polyethylene layer rises and melts. After that, the ends of the polyethylene pipe under the coupling are heated. At the same time, it expands, and the pressure necessary for high-quality welding is formed. After the power supply is turned off, the pipe cools down, and the welded seam with the welded sleeve, hardening, forms a rigid hermetic joint.

Technology for welding HDPE pipes with an electric coupling

Before the welding process, preparation is carried out: dirt is removed from the pipes, their edges are cleaned, and the inner surface of the electrical coupling is degreased.

After that, the edges of the pipes are inserted into the coupling and the entire structure is fixed in the positioner.

To find out the welding parameters, read the bar code on the fitting or manually enter the specified values on the electric welding machine.

The contacts of the electrical coupling and the welding machine are interconnected and voltage is applied.

After the end of the process of connecting the coupling and the ends of the pipes, the power is turned off, and the structure is left to cool, strictly observing its immobility. After the pipe has cooled, it is removed from the positioner and the welding protocol is printed out.

If the pipe to be welded has a large diameter, a point for additional heating of parts can be added to the technology.

Prices for equipment for welding HDPE pipes

HDPE pipe welding equipment

Video - Electrofusion welding of HDPE pipes

DIY butt welding of HDPE pipes

Butt welding is a technologically more complex process than connecting HDPE pipes with an electric coupling. Work can be taken only with the qualification of a welder and relevant work experience.

During butt welding, a monolithic seam is formed, which is not inferior in technical parameters to other surfaces of polyethylene pipes, without violating the flexibility of the structure. In this way, pipes are connected to each other, and fittings and other parts are also installed.

Butt welding is applicable only for joining parts of the same grade of polyethylene, diameter, SDR with a wall thickness of more than 4.5 mm and a diameter of more than 50 mm. The temperature regime for operation must correspond to the range from -15°С to +45°С.

Technology of butt welding of polyethylene pipes

At the preparatory stage, the ovality of polyethylene pipes is checked, their wall thickness is compared, and the compliance with the SDR of the parts to be welded is compared. After that, chips, bumps are hit from the ends (you can use an electric trimmer that cuts the pipes at an angle of 90 °), cleaned of contaminants (dust, sand, moisture, etc.).

After that, the primary flash is formed by melting the ends of the pipes on the welding machine.

The heater acts on the ends of HDPE pipes. In this case, heat spreads deep into the polyethylene, the process of its melting begins.

After keeping the heating part of the welding machine at the ends of the pipes for a certain time, which is selected depending on the size and thickness of the products, it is carefully removed, and the heated pipes are joined together. It is important that the time spent on removing the welding machine and joining the heated ends of the pipes is minimal.

On hot polyethylene, after joining, a final flash is formed. Proper pressure is provided by a machine with a hydrodynamic mover.

When the polyethylene cools down, you get a uniform sealed seam - a shoulder. In case of making mistakes in the technological process / installation, the seam turns out to be inhomogeneous or curved. It is important not to allow the pipe walls to shift relative to each other by more than 10% of their wall thickness.

Video - Butt welding of polyethylene pipes

The cost of work on butt welding of HDPE polyethylene pipes:

HDPE pipe diameter, mm	The price of welding HDPE pipes for one joint (in rubles)
	500,00
	600,00
	800,00
	1 300,00
	2 500,00
	from 3 200.00
	from 4 500.00
	from 6,000.00
710	from 7 300.00
800	from 8 500.00

They are specified at the conclusion of the contract and depend on the features of the object and the amount of work.

Welding of one joint of HDPE polyethylene pipe.

The DVN-Stroy company provides services for welding one joint of a HDPE pipe. At the same time, the minimum cost of work at a butt is 10-12 thousand rubles (depending on the remoteness of the object and the availability of electricity 220V), socket welding of polyethylene pipes - 6-8 thousand rubles.

Electrofusion welding of plastic pipes.

The DVN-Stroy company carries out electrofusion welding of pipes.

The cost of work on electrofusion welding of HDPE polyethylene pipes.

Pipe diameter, mm	Price of socket welding of HDPE pipes for one connection (in rubles)


	1200
	2000
	2800
	3500

Advantages of socket welding of plastic pipes.

The main advantages of the coupling connection of polyethylene pipes are the speed and ease of work, as well as a small space for work. Welding with the help of electric couplings consists in melting the polyethylene of the connected pipes when the metal spiral of the embedded element is heated. An integral connection is formed during the subsequent cooling of the welded joint.

Electrofusion welding of HDPE pipes, technology for connecting pipes with couplings.

The process of welding pipes using embedded electric couplings is carried out in the following sequence:

The ends of the connected polyethylene pipes must be cleaned of dirt and degreased.
The electric coupling is put on the end of one of the pipes, until the end of the coupling and the HDPE pipe are aligned. If necessary, the pipe is clamped in the positioner.
The second pipe is aligned with the first "end to end", after which the coupling is pushed in the opposite direction by 1/2 of the length of the coupling.
The wires from the welding machine are connected to the terminals of the electrical coupling. The heating process of the electric coupling starts, automatic mode. Pipe welding is complete when molten polyethylene emerges from the test ports of the fitting.
Natural cooling of the welded assembly to complete immobility.

How else are they looking for pipe welding services using electric couplings on the Internet? The most common phrases: