Pipe connection Effective connection of pipes

For their installation, you can use various pipesfor example, low pressure polyethylene (HDPE). Such products are used both in pressure and in non-pressure systems. But in order to use such pipes, you need to know the technique of working with them. This article will talk about how to connect the HDPE pipe.

The advantages of using HDPE pipes

Today, pipes made of polyethylene under low pressure are in great demand. This is facilitated by the positive qualities of such products. Namely:

Long service life (more than 50 years).
Immunity to aggressive environments.
Corrosion to such pipes is not terrible.
It is possible to carry out laying in a trenchless manner, which significantly reduces the cost of all work, but limits the period of use of such a water supply.
The inside of the pipe is very smooth. This prevents deposits and growths from forming, which eliminates the appearance of blockages.
Pipes are very light, it greatly facilitates and accelerates the laying of pipelines;
HDPE products are not afraid of temperature extremes.
Pipes have great ductility. The constructed pipeline easily transfers soil shifts. That is why such pipes are often used in earthquake-prone regions.

But there are some disadvantages. So, HDPE pipes do not tolerate ultraviolet radiation. Also, such pipelines are not intended for pumping liquids with high temperatures, as a result of which they can be deformed.

Butt welding

For welding butt pipes, special equipment is used. At the same time, it is very difficult to carry out such work on your own, for this you need to have special qualifications. Butt welding of PND pipes is carried out in two ways:

using a mechanical welding machine;
using an electro-hydraulic welding unit.

The first method is used only when installing low pressure pipelines. These include sewerage and sewage systems at industrial enterprises. Electro-hydraulic equipment is able to create pipelines for any purpose. Compounds made using this method are strong and durable. The pipelines themselves can withstand great pressure and any mechanical stress.

For welding pipes, various parts from HDPE can also be used. So, the industry produces bends, crosses, tees, transitions, etc. With their help, you can create a piping system of any configuration.

But, as mentioned above, welding requires the use of special equipment and sufficient experience. For these reasons, this method is rarely used in everyday life. A simpler, but no less reliable way to connect HDPE pipes (and not only among themselves) is to use fittings.

Using Fittings

HDPE pipes can be connected using special fittings. Such designs are used when creating communications from pipes of small diameter (up to 50 mm). You can use the following types of fittings:

electric welded;
compression;
reducing.

The first option is a coupling with an electric heating element inside. When connected (after connecting to electricity), the fitting heats up and melts the polyethylene. The result is a solid and reliable connection, but at the same time indistinguishable.

For work, you must first clean the pipe and fitting from dirt. Then they are set on the same axis, while achieving immobility of the entire structure. After that, the connecting element is connected to a current source specially designed for these purposes. As a result of heating, the plastic begins to melt, tightly connecting all the elements. You can learn more about working with such connecting elements by watching a video from the Internet.

The easiest way to connect HDPE pipes is to use a compression fitting. Any person can cope with this task, even without possessing any skills. Such fittings consist of:

polyethylene housing;
o-rings;
clamping rings (they protect the connection from mechanical damage);
bushings;
nut covers.

Before starting work, you need to disassemble the design of the connecting element. Then at the end of the pipe we mark the distance at which it should go into the fitting. Next, after wetting in water, we put on the connecting element. The last action is to tighten the nut cover (no excessive force is needed). The result is a compound without the risk of leakage, moreover, collapsible.

In addition, compression fittings have another plus - this is the ability to connect different (in material) pipes. Very often, when repairing an apartment, it is necessary to connect communications to old metal pipes. Using compression fittings to make such a connection is very easy. The process is the same as in the case of joining two pipes made of polyethylene.

Reducing fittings are used if it is necessary to connect two pipes of different diameters. The principle of use of this connecting element is the same as that of compression.

We use flange connection

Very often flange elements are used to connect HDPE pipes. This method is used when connecting large diameter pipes, as well as flanges when connecting to various valves and pumps. Such a connection can be quickly dismantled for repair and cleaning.

The flange coupling itself consists of two nodes:

Compression flange.
Mounting flange.

The first component is used to fix the joint section from the side of the HDPE pipe - it works on the principle of a compression sleeve. The second unit is a regular flange, with normalized dimensions. And this flange is mounted on the second part of the connection (pump inlet, metal pipe etc.).

Video

This video shows how to connect pipes with a compression sleeve:

(abbreviation means that they are made of polyethylene produced under low pressure). As a rule, PE 80 and 100 grades are used for them.

The main advantage of these water flows is the flexibility of the material and the minimum labor-intensive installation of pipeline facilities. Any person who does not have a special skill will cope with the installation of such a structure.

Also, the conductive components from HDPE are advantageous in that they are not susceptible to corrosion, can be laid without a special trench, resistant to soil movements, have a low weight, and are resistant to aggressive effects of various environments. The service life of such a hydraulic line is more than 50 years. Due to their smooth walls, HDPE structures retain throughput for the entire service life, since slippery polyethylene does not contribute to buildup of foreign substances inside the water flow.

Articulation of individual sections of the conductive hydraulic line may occur in two different ways - detachable and one-piece. How to connect HDPE pipes without welding - fittings? The choice of method is determined by the purpose of this facility.

One-piece connection most often used if the fluid will be supplied there under pressure. End-to-end pipe fragments are fastened by mechanical or electro-hydraulic welding.

Split water pipes created in case of installation of gravity systems. For example, it can be a house sewage system, where water will definitely not come under pressure. Also, devices made of elements of small cross section, from 50 mm and below, and conductive lines are assembled in a collapsible manner, where a configuration change is obviously assumed during the operation of the pipeline.

Detachable combination of pipes PND can be flange, coupling, collet crimp, that is, through fittings. This method is considered the most technologically advanced and less labor intensive.

A fitting in plumbing is called the connecting part of the pipeline system, which is installed at the joints of the ducts, branching sections of the device, turns, joints of fragments of various diameters.

Also connecting parts mounted in the places of the alleged disassembly of the conductive line in order to repair, connect additional elements or change the configuration.

Varieties of elements

Fittings for assembling individual elements into a single conductive network are of several types. They are made, as a rule, of polyethylene, but there are also brass ones. By purpose, you can divide them into several categories:

Connection of HDPE pipes of the same diameter with compression fittings
Assembly of pipelines from conductive sections of different sections
Branching, in accordance with the general scheme of the pipeline
Docking of PND pipes with different types of fittings
Turning a highway
Stub installation

Most often these connecting elements used to create collapsible structures, but there is a variety used to create an integral pipeline - an electric-welded or welded fitting.

According to their design features and scope docking components can be divided into several types:

Couplings for connecting HDPE pipes. They, in turn, come in three main categories: equal passage, for sections of the same section, flanged, for thick waterways, and compensation, for connecting highways of different diameters.
Bends. This design is used to form pipe turns.
Adapters. Serve for joining various fittings or a section made of another material: cast iron, metal.
Tees and crosses. Used to create branches of a conductive network.
Stubs. They are used to shut off liquid or gas entering the system.

Each type of this device is designed for a separate type of piping system.

What advantages in comparison with other species have, read in a special review.

Useful information about technical specifications polypropylene pipes for and water.

Learn about the features of the use of polyethylene pipes and fittings in the plumbing sphere from this.

Mounting Methods

Assembly methods for the connecting structure are divided into three main types:

Electric welded fittings are an alternative to butt welding, which is used to create non-separable assemblies. This spare part is a polyethylene crimp socket, inside of which there is an electric heating coil. Even an aspiring repairman can connect HDPE - elements by means of electrofusion welding.

The edges of the fragments to be connected should be inserted into the socket and the welding machine should be connected to the assembly. Due to the barcode - marking indicating the required temperature, pressure and duration of welding, which each part has, all the characteristics will be automatically selected by the device.

The fastening is very durable, so this method of installation is most often used in the most critical nodes.

Welded - cast metal couplings or tees, the assembly of which is carried out by welding. The so-called “butt” ones are also often made, where the role of the connecting part, in fact, is played by small fragments of a pipe welded end-to-end with the main hydraulic line.

Compression - The most convenient option for creating a collapsible conductive network. Such connecting parts are very popular due to their low cost and ease of installation.

The compression fitting consists of a PET body, gaskets that are located at the junction, clamping rings that perform a protective function, a pressing sleeve and a nut that tightly closes the joint.

The material from which the compression fitting is made may vary. Diameter varies from 16 to 110 mm.

The assembly of the compression docking unit is carried out in several simple steps:

First you need to prepare both parts to be joined. To do this, you need to measure how deep the end of each of them will go into the articulating socket. At this point, a mark is applied to the pipe.
Then it is necessary to lubricate the surface of this area with soap and water to improve slip. Then putting on the fitting will be much easier.
Unscrew union nut of connecting structure.
Insert the pipe into the fitting o-ring to the mark.
Tighten the top nut.

If the installation is completed correctly, the joint will be tight and durable.

How to connect HDPE pipes using fittings - you can see an example of the connection in this video:

Other methods

Basically, when installing detachable pipeline structures compression joints are used. With a lot of advantages, such as ease of installation, low price and various sizes, they have practically no drawbacks.

But there is some more solutions for creating collapsible docking nodes, which from time to time are used in the construction of conductive hydraulic lines:

Pipes made of low pressure polyethylene are suitable for a wide variety of installation options. Docking them through fittings reduces the cost of the task and makes the creation of a system less labor intensive. Assembly of structures without the use of welding is much faster.

Compression or crimp sockets are very popular when creating pipeline structures and are as simple as possible to install. Nevertheless, in the most critical places it is recommended to use connecting elements mounted by electrofusion welding.

The right choice of fittings according to the characteristics of each system guarantees the quality of the docking units and the long life of the pipeline.

Pipes made of polyethylene are a modern high-tech material that is widely used for the construction of pipelines for transporting various media.

This type of pipe is also popular because the installation of pipelines can be performed by a layman. Let's consider how HDPE pipes can be connected, and what advantages each installation method has.

Polyethylene pipes are widely used in construction and in everyday life.

For example, these products can be used:

For the construction of a pipeline for supplying water;
For installation of sewage systems;
To protect power cables when laying electrical networks;
To create waterproofing membranes when laying heating mains;
To protect communication cables;
For construction artesian wells;
For use as forming parts in the construction of monolithic buildings.
To create irrigation systems in greenhouses, etc.

Such widespread use, not least, due to the ease of installation. Consider methods for their connection.

Methods used to connect HDPE pipes

All existing ways to connect two polyethylene pipes can be divided into two types.

One-piece connections, i.e. welding.
Detachable connections using fittings.

The latter option is used more often, here are its main advantages:

Saving. There is no need to purchase special equipment for welding or pay for the services of a master.
Availability. A detachable connection can be made where the use of welding is not possible, for example, under water.
Speed. This method allows you to connect parts with high speed.

Performing a detachable connection of pipes from HDPE

The detachable connection of pipes can be performed in the following ways:

Socket connection. This method requires elastic seals. Such a connection is most often performed during the construction of a pressure-free sewage pipeline.
Flange and fitting connection using special fasteners.

Use of couplings

At construction of pipelines couplings for PND pipes are widely used.

This part is an element made of polyethylene. For the manufacture of couplings, the extrusion method is used.

This connection method allows you to not use welding machines, that is, does not require the purchase of special equipment. Moreover, the couplings for HDPE pipes themselves are quite cheap, so that their use allows you to save on construction.

Additional benefits of using couplings:

Long service life of several tens of years.
Reliability of fastening.
High resistance to temperature changes, as well as to mechanical stress.
Resistance to aggressive environments.
A wide range of applications, the coupling for HDPE pipes can be used for the construction of the pipeline for almost any purpose.

The following types of couplings are distinguished:

The coupling is compression. This product is available with both external and internal threads. This product is widely used in the construction of heating and gas supply systems. Using this part, steel and polyethylene pipes are docked.
For quick and reliable connection of parts of the same diameter, a coupling is used for PND pipes.
Reducing coupling necessary to connect pipes having different diameters.

Pipe connection with compression fittings

The work proceeds according to the following algorithm:

The compression fitting should be disassembled by unscrewing the union nut.
The pipe is cleaned of dirt, a bevel is performed at the end.

A chamfer should be used for chamfering, however, in the absence of this tool, you can use a sharp knife.

A mark is made on the pipe with a marker, which should characterize the depth of entry into the fitting.
Before introducing the part, the pipe should be moistened with liquid soap.
The pipe is inserted into the fitting; when performing this action, some force will have to be applied, since the rubber sealant creates resistance.
The fitting nut is tightened.

When tightening the nut, it is important not to overdo it so as not to overtighten the joint.

Performing one-piece pipe connection from HDPE

In some cases, it is more advantageous to use the pipe welding method, that is, the formation of an integral connection. Consider how to connect HDPE pipes by welding. Currently, two methods are used - butt welding and connection using electrofusion couplings.

Electrofusion welding

This type of welding is carried out using a shaped part (sleeve) made of polyethylene, into which electric spirals are inserted. When voltage is applied to the spirals, the pipes heat up, and they are welded to the inner walls of the coupling.

Requirements for the process:

Preliminary cleaning of pipes;
The immobility of the parts during heating and cooling.

Butt welding

This method of connection is carried out by using a special apparatus in which the edges of the pipes are heated. After heating, the parts to be welded are joined together, and when the plastic cools down, a reliable connection is obtained.

When connecting butt welding, pipes with pronounced ellipse are not allowed in the work.

Requirements for welded joints on polyethylene pipes

The butt seam cannot be located below the outer surface of the pipe.
When welding two segments, their displacement relative to each other should not exceed ten percent of the wall thickness of the pipe used.
The height of the roller on a high-quality weld does not exceed 2.5 mm for pipes having a wall thickness of up to 5 mm, and should be more than 5 mm when using thick-walled pipes (wall thickness 6-20 mm).

findings

The choice of another method for connecting pipes should be made taking into account the operating conditions of the pipeline — whether it will be pressure or not, what medium will be supplied through the pipes, etc. The correct choice of the method of connecting pipes will ensure the reliability of the pipeline system.

Pipes made of low pressure polyethylene (HDPE) are used for laying pressure and pressureless pipelines. This material has a lot of advantages - flexibility, low weight, ease of installation and more. In addition, almost any cold, up to 40 ° C, liquids and gaseous substances can be transported through such pipes.

In addition, in order to assemble a system from pipes, there is no need to have professional skills, even a person can cope with it without any practical experience. Such pipelines are used both in production and in housing construction. In the article, we will consider how the connection occurs and by the method.

Methods of connecting pipes

Connection methods can be divided into two groups:

one-piece;
detachable.

Each of these groups, in turn, is divided into several subgroups:

One-piece:

butt welding;
electrofusion.

Detachable:

With compression fittings.
Coupling connection.

The choice of connection depends on the particular type of pipeline. For example, for pressure systems, butt welding or electrofusion welding is used, and for pressureless pipelines, simpler detachable ones are used.

Video: Assembling HDPE connections and pipes

Detachable connection

In this way, the pipes are fixed if in the future it may be necessary to dismantle or the use of welding is impossible, well, or impractical. Of course, such a mount is not as reliable as welding, but still it has its advantages:

Savings - no additional equipment required.
Quick installation - the pipeline is assembled in almost a couple of hours.
Plug connections are made where welding is not available, for example, under water.

On a note!

The socket connection is mainly used for the installation of a gravity pipe, for example, for sewage. The connection using fittings is similar in reliability to welding, so it can be used for installation of water pipes.

So, for a system in which fluid is transported by gravity, one of the two simplest methods is used:

In the bell - one end of the pipe is inserted into the bell of the previous one, and rubber or silicone seals are used for tightness.
Fitting or flanged - the pipeline is connected using special parts.

Coupling

The coupling is made of polyethylene and is widely used in the assembly of pipelines. In addition to the fact that with their help it is possible to quickly assemble pipes into a single unit without any hassle, they have a number of advantages:

It turns out a reliable mount with a long service life;
Withstand temperature extremes and mechanical stress;
It can be used for any types of pipelines.
Affordable price.

Installation of the pipeline is carried out using different types of couplings:

Compression - can have different threads: external or internal. Compression couplings can be used even when assembling gas systems and water pipes.
Connecting - connect elements of the same diameter.
Reduction - pipe elements of different diameters are indispensable for connecting.

PND fitting connection

This method is used when connecting pipes of small diameter: 20 - 35 mm. Assembly as well as the previous method is not something super complicated and is carried out as follows:

Remove the nut from the fitting.
The end part of the pipe is cleaned and chamfered; for this, a special tool is used - a chamfer or, in its absence, a sharp knife.
At the edges, a mark is made on the depth of entry into the fitting, and lubricated with soap or silicone grease.
The pipe is inserted into the fitting to the mark and tighten the nut.

One-piece connection

When assembling pressure pipelines, it is necessary to make strong and reliable connections, so welding is used for them. There are two types of welding:

Butt
With the help of electric couplings.

It’s easy to carry them out, you can do it yourself, the main thing is to get the necessary tools and equipment.

Butt welding

This method is used to assemble systems from pipes with a diameter of 50 mm or more. This requires the presence of a soldering iron for welding HDPE. Such equipment is inexpensive, and is sold in almost any hardware store, so there should be no problems with the purchase. The process goes as follows:

The ends of the pipes are fixed in the apparatus, after which a heated plate is brought to them. When the polyethylene begins to melt, the plate is removed, and the pipes are connected to each other under slight pressure. After the seam cools down, the retainers remove and remove the pipes.

Technological features of the method:

Used to connect elements of the same diameter.
Do not weld parts with a wall thickness of less than 5 mm.
You can only weld at a temperature of + 15 ° to + 45 ° C.

Electrofusion welding

A pipeline assembled using electrical couplings can withstand pressure up to 16 atmospheres. But, for each joint, it is necessary to purchase special pads - electrowelded couplings. These details are quite expensive, so if you plan to make a lot of joints, it is better to use butt welding.

Conditions that must be met before starting work:

Cleaning the ends;
Rigid fixation of the elements to be welded.

The process itself looks something like this:

The ends of the pipes are cut to get a right angle and chamfer;
The ends are cleaned;
Pipes are fixed in the coupling and power is supplied to the terminals;
The device turns on, by heating the surface inside the coupling softens;
The device and wires are turned off;
The resulting joint is cooled.

Conclusion

When choosing a method for connecting HDPE pipes, take into account the nuances and installation sequence. Installation of almost any pipeline can be carried out independently, without resorting to the services of construction companies.

Video: KELL 3000 Electrofusion Welding Machine for PE Pipes

Polymers are firmly rooted in our lives. A variety of objects and designs are made from this raw material. In modern sewer and water systems (and in other pipelines), HDPE pipes are used. Such products have the same strength as metal counterparts, but it is much easier to install and last much longer. It is possible to create pipelines from polymer pipes without special machinery or equipment. How to connect pipes HDPE fitting will be described in this article.

Connection Methods

To make a sewer or water supply, pipes must be connected, while the junction can be collapsible or non-collapsible. The second method involves welding. For this it is necessary to use special devices.

A collapsible joint has many positive qualities. Here are just the main ones:

Ease of installation. All work can be done independently, even without an assistant.
Possibility of dismantling. If the pipes become clogged or damaged, repair work can be done easily.

That is why almost all HDPE pipe connections (especially in houses and apartments) are made using fittings or couplings.

For the installation of pipes made of polymers, several types of fittings can be used. Namely:

Electric welded. It is a design with a special element. With the help of electricity, the wire is heated, which melts the plastic and creates a strong joint. With the help of such a fitting an integral connection is created.
It is this design that is most often used in the installation of various pipelines.
Reduction.This fitting is designed to connect pipes of various diameters.

Electrofusion fittings are used very rarely. This is due to the inseparability of the resulting connection and the high cost of the device itself. Reducing fittings are used when connecting pipelines to meters and other communication elements. But compression structures are used most often.

Fittings themselves can have a different geometry. Both direct connections and at various angles are used. Various splitters, tees and other designs are also widespread. In addition, can be used as fixed joints, and with the possibility of displacement of the pipes relative to each other.

The most commonly used compression fitting. This is due to the simplicity of its application. How to connect HDPE pipes using compression fittings? This will be discussed now. The first step is to understand the device of this design. Compression fitting consists of:

polyethylene cases;
o-rings;
clamp rings are used to protect against mechanical damage;
bushings;
nut covers.

Such fittings are available in various diameters. In stores you can find a design for pipes from 16 to Ø 110 mm.

To connect pipes using a compressor fitting, the following instructions must be followed:

Disassembled fitting design. The cap-nuts are unscrewed and the ends of the pipes are put on them (first you need to chamfer them with a well-sharpened knife or chamfer).
We mark at the ends of the pipe the distance by which they must enter the pipe. To facilitate the connection, you can moisten the fitting itself and the ends of the pipes with water or a mild soapy solution.
Insert the pipes into the fitting to the marked length. In this case, physical effort will be required. So the pipe will fit tightly into the o-ring.
Then tighten the nut cover. It is advisable to do this without using the tool with your hand. This reduces the risk of overtightening the nut, which means that the tightness is worsened. This completes the connection process.

When using an electric-welded fitting, a source of electricity is required (generator or electrical outlet). Pipes and the connecting element itself are cleaned of contaminants and fixed on the same axis. In this case, it is necessary to achieve immobility of the entire structure.

Then a current source is connected to the fitting. As a result, the heating element begins to melt the plastic. In the molten state, the material creates the necessary pressure, and the pipes are firmly connected.