How to connect polyethylene pipes. Connecting polyethylene pipes - methods What are flanges for connecting dissimilar pipes

When settling in modern systems sewerage, heating, water supply are often connected polyethylene pipes fittings. Also, when laying household communications, flanges are used, which make it possible to assemble pipe products from different materials.

Polyethylene (PE) pipes in last years are actively displacing traditional cast iron and steel products from the construction market. Plastic structures are superior to metal ones in a number of indicators. Therefore, this process has a completely logical explanation - everyone wants to have reliable and inexpensive heating and sewer systems in their home, assembled without welding. During installation you have to face one problem. It lies in the fact that many elements household pipelines in apartments are made of metal products.

Connection of plastic and metal pipes

And here it is important to correctly connect PE pipes with steel (cast iron) pipes. This can be done in two ways: using flanges and fittings. A flange connection of polyethylene (polypropylene) pipes with steel pipes is recommended for cases where systems of products with a cross-section of more than 50 mm are installed. But pipelines with a diameter of up to 50 mm are better connected with fittings. They are special elements that have a smooth coupling for connecting PE pipes and threads for metal pipes.

The flange is made in the form of a threaded part. It is most often used to connect metal and polyethylene water pipes, as well as gas communications without welding. Flanges for assembling household networks from different materials have not only threads on one side, but also a mandatory seal. The latter is located at the second end of the described element. The seal guarantees a tight and truly strong connection, which can always be disassembled if necessary.

Example flange connection

To lay communications you can use:

1. metal flanges;
2. flanges for special bushings (they are called collars).

Experts advise home craftsmen to connect PE pipes using the second the above methods. In this case, the connection is of the highest quality. Flanges for bushings are made of steel 20. Flanges for polyethylene pipes are designed for operating pressure up to 1.6 MPa. These parts are manufactured with a cross section from 20 to 1200 mm. Therefore, problems with selecting suitable elements for creating detachable connections never arise. There are several subtleties of assembling communications using flanges. We present them below:

• flanges supported by cone-type bushings should be used when working with pipes with a cross-section above 200 mm;
• light pipe products made of PE with a diameter of 150–300 mm, as well as heavy ones with a cross-section of less than 150 mm, are best connected using flanges with a straight shoulder;
• To increase the strength characteristics of connecting pipes made of different materials, you can use straight-shaped bushings with a special conical transition.

When choosing flanges for creating detachable connections, pay special attention to the quality of fasteners. They are not allowed to have burrs or sharp edges. Such defects can cause damage to PE pipes. The flange connection of polyethylene pipes with a cross-section of more than 50 mm is made according to a simple scheme. You need to evenly cut the pipe product in the place where it will dock with another part of the communication. After this, you carefully pull the flange onto the pipe and put a rubber gasket on top.

Such sealing element can extend beyond the cut by a maximum of 1 cm, no more. You then slide the flange over the gasket and mate it (using bolts) to the mating flange. The bolts must be tightened very carefully. If you apply excessive force during this procedure, the polyethylene pipe may crack.

Separate elements of communications (heating, water supply) in an apartment or house are often connected with fittings. These elements are indispensable for connecting polyethylene pipe products to metal filters, meters, mixers, pipes and other parts of a modern pipeline. The fittings are cut into external or internal threads. Structurally, as noted above, they are special adapters with a thread and a coupling.

Pipe connection fittings

When choosing fittings, it is necessary to take into account the diameter of the metal pipe into which they will be cut.

Adapters are ideal for cases where the pipeline has a lot of bends and turns. The assembly of the system (steel or cast iron pipes plus polyethylene) using fittings is carried out as follows:

1. Unscrew the coupling of the metal pipe product. If the junction of PE and steel pipe falls on a different area, you will need to cut off the old metal product. And then you need to lubricate the cut edge with oil or grease and use a thread cutter to make a new thread for the fitting. The operation is not difficult for a more or less experienced self-taught craftsman.
2. Carefully wipe the threads on the pipe, wrap it with fum tape or ordinary tow. After this, apply silicone on top. The ribbon or tow is wound quite a bit. It is enough to perform a couple of turns. In this case, the edge of the wound material, when clamping it, must be directed along the thread.
3. Using your hands (do not use a wrench or other tool), carefully screw the connecting fitting onto the thread. If there is strong pressure on the adapter, there is a high probability of it cracking.
4. Insert a PE pipe into the coupling located at the second end of the fitting and solder it.
5. Treat the connection with sealant.

Basically, that's it. You have connected a polyethylene (or polypropylene) pipe to a steel pipe. Turn on the water (if a water supply system was made) and check the fitting location for leaks. If there is one, simply tighten the adapter a little. The final work is the treatment of the joint made with sealant. You can fully use the pipeline after 3–4 hours. During this time, the sealant will dry completely.

Flange connection of polyethylene pipes

1. Polyethylene pipe;
2. Bushing for flange;
3. Loose flange;

The selection of shut-off, control and other valves installed on polyethylene pipelines is carried out in accordance with the standards technical specifications, catalogs, parameters of transported substances, taking into account the requirements of the project and operating conditions.

Pressure polyethylene pipelines are connected to pipelines made of other materials using detachable steel flange connections.

The bushing for the flange at the base of the collar has a special structural expansion designed for more reliable connection of the collar. After all, it is on the bushing collar that the main pressure occurs during pipeline operation. Conventional flanges supplied for steel pipes in accordance with GOST 12820.80 cannot be freely installed on the sleeve due to the narrow internal diameter. Therefore, for flange connections of polyethylene pipes, free bored flanges are used in accordance with GOST 12822.80 with an increased internal diameter d1, which allows you to freely put it on a PE pipe.

Flange free

d- inner diameter flange according to GOST 12820.80;
d1 - free bored flange according to GOST 12822.80.

Types of connections

Thus, to connect dissimilar pipes, use:

• NPSP - permanent connection in gas, sewer and water mains, for which an adapter is used special purpose. The connection is essentially a welding of a polyethylene pipe to a steel pipe.
• Compression couplings equipped with threaded threads - compression fitting. It is used in conjunction with ferrules and gaskets, which can be changed as they wear out.
• Flange transition.

What are flanges for connecting dissimilar pipes

Connecting pipes made of dissimilar materials using flanges is optimal when installing a pipeline in which it is necessary to connect a metal pipe with HDPE or shut-off devices. For this purpose, a sleeve is used together with a pressure flange, which in turn is secured with bolts. The collar (the second name of the part) prevents the flange from slipping when the pressure in the pipe increases.

There are two types of bushings:

• Segmental, i.e. HDPE elements connected by butt welding.
• Cast structures with no welds. The cast HDPE bushing provides the flange with the necessary support and prevents the unit from coming apart. It is also assumed that there is a second flange on the metal pipe.

The part is easy to install and does not require special maintenance. A variety of standard sizes allows you to select bushings of any size for any pipe diameter.

Flanges are also divided into two types:

• Fixing when the flange is put on metal pipe, and a HDPE pipe product is attached to the other end and the entire structure is secured using a clamping ring and seal.
• Threaded - the flange has a thread on one side onto which a HDPE pipe with a seal is screwed.

Note! When installing, it is important to pay attention to the smoothness of the steel parts: any burrs or protrusions can damage the polyethylene.

NPSP

The design is most often used when replacing phased sections of a metal system with polyethylene, as well as for installing shut-off valves.

For installation, thermistor welding is used, when the end of a polyethylene pipe is heated with a special tool and melted to a viscous mass, and then connected to a steel pipe under pressure. This connection is used for installation of high-pressure pipelines.

Regulatory documents regulate the technical characteristics of NPSP:

System pressure limits:

• for gas lines PE 80 - 6.4 bar, PE 100 -10 bar
• for water pressure systems PE 80 - 12.5 bar PE 100 - 16 bar

The length of the pipes is regulated by GOST TU4859-02603321549-98 - for gas, and TU2248-001-86324344-2009 - for plumbing systems, working under pressure.

Compression coupling connection

This is a collapsible modular design, the parts of which are easy to replace.

The body is made of polypropylene, equipped with a pipe stop and a trapezoidal thread. Fixing sleeve with sealing gasket, which ensures tightness and prevents the pipe from deforming and shrinking. The crimp ring securely holds the pipe in a stationary position.

Mainly used for plumbing systems.

Couplings come in different shapes:

• transitional,
• connecting,
• square,
• plug,
• tee,
• branch

They can have both internal and external threads.

The part diameter varies from 16 to 110, and the working pressure value ranges from 10 to 16.

Methods for joining polyethylene pipes

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During a major or current repairs The question often arises - how to connect a plastic pipe to a metal one, which is associated with the need to replace worn out sections of communications of various lengths. A similar problem may arise during the construction of a private household - when connecting to centralized engineering systems. Correct joining of pipes made of various materials, is not inferior in reliability to connections of identical pipes, so it is important to find out in advance how to connect dissimilar sections.

Cases of connecting dissimilar pipes

Some cases where connection is necessary plastic pipes with metal ones, described above. In most cases, systems installed a certain time ago turn out to be metal. Currently, plastic is chosen not only because of its reasonable price and good technical characteristics, but also because large selection standard sizes of pipes and fittings, making it easy to find components of any configuration for replacement.

An example of connecting a plastic pipe to an iron pipe

Sometimes pipes made of different materials (metal and plastic) are used when installing a system from scratch. For example, when laying an external section of water supply or sewerage for a private house, sometimes it is necessary to lay pipelines under a car entrance or parking lot. The dynamic load on the ground surface during vehicle movement will be transferred to communications located in the ground. It is recommended to install metal pipes in these areas, however, using metal to install the entire system is not economically feasible and less practical.

Methods for connecting metal pipes to plastic ones

There are two ways to connect plastic pipes with metal ones, which are used for steel pipelines.

• Threaded connections are used in cases where the diameter of the pipes being connected does not exceed 40 mm.
• Flange connections are optimal for large diameters, since tightening the threads in such cases can be difficult.

Features of threaded connections

In order to understand how to connect a plastic pipe to a metal pipe using threads, you should study the fittings used for these purposes. They are adapters, on one side of which there is a thread for connecting a metal pipeline and a smooth coupling for soldering plastic pipes on the other. There are also models for connecting a larger number of dissimilar lines, as well as fittings for making turns and bends.

Polypropylene fittings with threads for transition from polypropylene to metal

The threaded connection of steel and plastic (polypropylene) pipes is performed in a certain sequence.

1. The connection point is prepared from the side of the existing metal communications. If there was already a threaded connection in this place, it unscrews. If the pipes were welded or the installation location plastic insert is the middle of a whole steel pipe, the latter is cut, after which lubricant is applied to the edge and the thread is made using a thread cutter.
2. The end of the threaded steel pipe is cleaned and a sealing material is applied to it: tow or fum tape with silicone grease. In order to eliminate the possibility of leaks, it is important to perform sealing correctly - lay no more than 1-2 turns of winding in the direction along the thread.
3. The threaded edge of the fitting connects to the metal thread. In this case, you should not only not use special tools, but also not over-tighten the connection by hand. Significant force may cause the fittings to crack. It will not be difficult to tighten the threads additionally if after installation, during a test filling of the system, leakage is detected.
4. After completing work with the threaded part of the connection, the plastic pipe is fixed to the smooth coupling of the fitting by welding.

The fitting for polyethylene pipes (HDPE) at one end has a thread for connection with metal, and at the other there is a compression clamp for the HDPE pipe - unlike polypropylene pipes no welding required here

Making flange connections

The connection of a plastic pipe to a metal pipe without threads is made using flanges. Its advantage is the ease of dismantling for repairs or cleaning of communications.

Connecting elements for detachable connections of dissimilar pipelines are flanges of various types.

• Light structures with a diameter not exceeding 300 mm, as well as medium and heavy pipes up to 150 mm, are connected using loose flanges, with a straight collar for support. Such modifications are most common when installing communications in private households and high-rise apartments.
• For pipes of any type with a diameter of up to 200 mm, loose flanges with a tapered collar can be used.
• A shaped flange and a steel projection using a wedge type connection is a universal option.
• Maximum strength can be achieved using a straight collar with a tapered transition.

Flange connection for HDPE pipes

As preparatory work Before installing a flange connection, it is important to carefully inspect the prepared flanges. There should be no burrs on them, which during installation could cause damage to the plastic part of the connection. In most cases, such burrs are quite easy to remove.

The procedure for assembling a unit with a flange connection is as follows:

Installation of a plastic pipe to a metal pipe using flanges

1. The steel pipe is cut at the intended insertion site. It is important to make the cutting line evenly and accurately.
2. The flange is placed on the pipe.
3. To ensure the tightness of the connection, a rubber gasket is installed, the size of which should be such that it does not extend beyond the cut line by more than 10 mm.
4. The main elements of the assembly are connected - the flange placed on the pipe is combined with the gasket and fastened to the second flange using bolts.

Tightening should be done by evenly turning the fastener threads around the entire circumference and avoiding unnecessary force.

If you are wondering what is the best material to make a country water supply from, we recommend that you read our article “Plastic pipes for water supply in the country.” Types and installation tips.

The easiest way to install HDPE pipes is to use fittings. We have another article about compression fittings for polyethylene pipes.

If you need to choose press jaws for installing metal-plastic pipes, then here you will find useful information.

Features of connecting sewer pipes

When installing sewerage, a connection is often required cast iron pipe with plastic, which is structurally different from the joints of steel and plastic pipes. For such connections, special components are required:

• cuffs,
• corrugations,
• seals.

Transition sleeve cast iron-plastic

In most cases, selecting and purchasing components is not difficult. At the same time, and in those rare cases when it is not possible to find a suitable seal, the problem can be solved using available materials. The seal of the required size can be cut from microporous rubber, for example, from an old car mat. A long narrow tape is placed in the gap between the elements being connected and sealed using a blunt wide screwdriver. The sealing is done without excessive force so as not to damage the plastic. If a leak is detected during a test filling of the system, the connection can be further sealed.

Sealing the joint by caulking or cement mortar not acceptable.

• When embossing, the ductile plastic pipe is deformed, the joint will not be tight, and there is a high probability of leakage.
• Cement mortar will not last long. Due to the large difference between the coefficients of thermal expansion of materials, the seam with each drain hot water will become loose. In the near future, the cemented joint between the plastic and cast iron sections of the pipeline will crack and cease to be airtight.

Connecting plastic pipes with copper pipes is extremely rare, but special fittings for such connections can also be found on sale. They have two smooth couplings - one for soldering a copper pipeline, the other for connecting to a plastic pipe.

Advantages of using HDPE pipes

It is easy to assemble a water supply from HDPE pipes

Today, pipes made from low-pressure polyethylene are in great demand. This is facilitated positive traits such products. Namely:

• Long service life (more than 50 years).
• Immunity to aggressive environments.
• Corrosion is not a problem for such pipes.
• It is possible to carry out installation using a trenchless method, which significantly reduces the cost of all work, but limits the period of use of such a water supply system.
• The inside of the pipe is very smooth. This prevents deposits and build-ups from forming, which eliminates the possibility of blockages.
• The pipes are very light, this greatly facilitates and speeds up the laying of pipelines;
• HDPE products are not afraid of temperature changes.
• Pipes have great ductility. The constructed pipeline easily tolerates soil movements. That is why such pipes are often used in earthquake-prone regions.

But there are also some disadvantages. Thus, HDPE pipes do not tolerate ultraviolet radiation. Also, such pipelines are not intended for pumping liquids from high temperatures, as a result of which they may become deformed.

Butt welding

Butt welded HDPE pipe

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

• using a mechanical welding machine;
• using an electrohydraulic welding unit.

The first method is used only when installing pipelines with low pressure. These include sewerage and wastewater drainage systems industrial enterprises. Electrohydraulic equipment is capable of creating pipelines for any purpose. Connections made using this method are strong and durable. The pipelines themselves can withstand high pressure and any mechanical stress.

Welding a rotary elbow

Various HDPE parts can also be used for welding pipes. Thus, the industry produces bends, crosses, tees, transitions, etc. With their help, you can create a pipeline 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. Simpler, but no less reliable way connecting HDPE pipes (and not only among themselves) is the use of fittings.

Using fittings

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

• electric welded;
• compression;
• reduction.

Electric welded coupling connection

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 durable and reliable connection, but at the same time inseparable.

To carry out the work, you must first clean the pipe and fitting from dirt. Then they are aligned along one axis, thereby achieving immobility of the entire structure. After this, the connecting element is connected to a current source specially designed for this purpose. As a result of heating, the plastic begins to melt, tightly connecting all elements. You can learn more about working with such connecting elements by watching a video from the Internet.

Fitting

The most the easy way To connect HDPE pipes is to use a compression fitting. Anyone can cope with this task, even without any skills. Such fittings consist of:

• polyethylene body;
• O-rings;
• clamping rings (they protect the connection from mechanical damage);
• bushings;
• cover nuts.

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 it in water, we put on the connecting element. The last step is to tighten the cap nut (no need to use excessive force). The result is a connection without the risk of leakage, and it is also collapsible.

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

Reducing fitting

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

Connecting polypropylene pipes to each other

Diffusion welding

Now the question of how to connect polypropylene pipes is a popular one. The most common method is diffusion welding. In order to securely fasten them, fittings are used: couplings, angles, adapters.

When installing a cold water supply system, polypropylene pipes will definitely last up to fifty years. They will last approximately twenty-five years when installing hot water pipes. Please note that operating time depends on inlet pressure and temperature.

Polypropylene products are very durable and can cope with any changes in the system. Great pressure and low temperature conditions can in no way affect the duration of their operation. High pressure and temperature, which are recorded at the same time, will reduce the service life of pipes by five to seven years. There are no extreme loads in home pipelines that can deform them, so there is no need to worry.

Device "Fusiotherm"

If you are interested in connecting with each other, pay your attention to this device. Cold polypropylene products are joined, then the joint is processed using the Fusiotherm device. If you need to weld 2 ends of pipes, they are inserted into a special hole in the device, after preheating the device to two hundred and sixty degrees. Then they are pulled out and connected.

Socket soldering

If the radius is less than twenty millimeters, then they can be connected by manual welding. To connect to a metal part, you must use a different method. Required special soldering iron for socket soldering.

1. Cut a piece of the product with special scissors. If there is reinforcement, process it and clean the reinforcement layer in the cut area.

2. Put on gloves, heat up your soldering iron and start soldering.

3. Do everything quickly so that the joint area does not become deformed.

Connection of polypropylene pipes with metal ones

The question remains relevant: how to connect polypropylene pipes (in conditions high pressure) with metal ones? There are 2 methods. You need to choose one of them based on the radius.

1. For products with a radius of up to 20 mm, you need to use threaded connections on the metal part of the system. Fittings, on one side of which there is an ordinary coupling for mounting to plastic, and on the other - the required thread, are sold everywhere. In order to seal steel threads, use flax with drying oil or modern sealing materials. This will ensure the durability of the connection.

2. For larger sizes it is better to use flange connections. An iron thread with a radius of 300 mm cannot be screwed in by hand, even if you are a strong man. So how then to combine a metal pipe and a polypropylene pipe if they large diameter? Use special adapters that can be purchased at the store.

Threads and flanges allow you to connect metal and polypropylene pipes without soldering, which is very convenient.

The right choice of polypropylene products

It is difficult to choose any specific one from wide range, available from many manufacturers. There are criteria that must be followed when purchasing.

1. Products must be in accordance with the specifications of the plumbing/heating system.

2. In order to assemble the system with high quality, you need to purchase all parts from one manufacturer. This approach will allow you to create a reliable and durable structure.

3. When choosing, pay attention to the quality of pipelines and fittings. Evaluate the following:

• smoothness of internal/external surface;
• the presence of cracks, chips, bubbles, heterogeneous structure, foreign particles;
• correct geometry;
• same wall thickness.

4. Remember that polypropylene products designed for operation at temperatures not less than minus twenty. Ask the store how to store them in winter. Improper storage leads to product deformation.

5. If drinking water will be supplied through the water supply system, ask the seller whether the product meets sanitation and hygiene standards.

6. Buy only straight pipes, without bends. In stores they are stored vertically, so they gradually bend and cease to be straight. Be sure to pay attention to this.

7. Choose products from trusted manufacturers that have proven themselves and have all the necessary certificates. Trying to save money, you can buy a low-quality product that will not last you the entire operational period. Therefore, it is better to pay more once than to spend money again and carry out complex repairs to the plumbing/heating system.

Connection methods

Polyethylene pipes low pressure can be connected in detachable and permanent ways. Below we will talk about each of these methods.

Plug-in connections

This type of connection is used on diameters up to 315 mm inclusive, but it is advisable to use on diameters no more than 110 mm. It is as reliable as one-piece methods.

Its advantages:

• speed and ease of installation;
• economical - no special equipment required; couplings and other fittings are not too expensive;
• accessibility - can be used in cramped conditions, under water, for example.

Connectors (fittings, couplings) are mounted in the following order:

• the ends are carefully cut perpendicular to the length of the pipe; are cleared of burrs;
• the ends are chamfered (using special device or a sharp knife);
• a connecting element is placed on the ends (it fits into the adapter quite tightly);
• then carefully tighten the nut on the fitting.

Connection with couplings

This is the fastest way to assemble pipelines and does not require special equipment. Can easily be used at home.

Polyethylene couplings come in several types:

• connecting - connect pipes of the same diameter;
• reduction – used as a transition for different diameters;
• compression - designed for connecting PE pipes with various shut-off equipment, steel, propylene or PVC pipes ami.

Couplings can be straight or angular. Types of couplings are shown in the table.

Fitting connection

Compression fittings are a type of connecting parts for water pipes.

Installing them is similar to installing couplings.

Flange connection

It is used on large-diameter main pipelines (at least 40 mm) for installing gate valves, valves, regulators (for their subsequent removal for repair or replacement).

To secure the flanges, special couplings are welded to the ends of the pipeline, then the flanges are screwed onto them.

Permanent connections

Only possible method connections of large diameters.

Butt welding

It is advisable to use this type of welding to connect workpieces with a wall thickness of at least 5 mm.

The ends are cleaned, chamfered, inserted into a special heater, melted, then the workpieces are joined, pressed and held motionless until completely cooled.

Electrofusion welding

The two pipes being connected are inserted into a special coupling, inside of which there is a heating element. Then voltage is applied to it from a special apparatus, the coupling and workpieces are heated and welded. A very convenient welding method. And very expensive. For large diameters, the cost of the coupling will be much higher than the cost of the pipeline on your site.

When performing this type of welding, special attention should be paid to pre-cleaning the ends and keeping the joint stationary until it cools completely.

You cannot connect pipes with a noticeably pronounced ellipse - the quality of the seam will be unsatisfactory.

After welding, the welded unit must remain stationary until it cools completely.

Do not neglect cleaning the ends from soil, dust, sand, shavings and degreasing - these little things significantly affect the quality of the seam.

How to connect a HDPE pipe to a polypropylene pipe

Polyethylene and polypropylene cannot be welded. Correctly connect them together only using fittings. On the ends to be connected, you should weld or put on MCVs (couplings with internal threads) made of the appropriate material, screw a quick-disconnect threaded connection (“American”) onto one MCV, then connect two MCVs using a union nut.

How to join polyethylene and steel pipes

This joining is carried out similarly to the joining of HDPE and polypropylene. Steel pipeline, as a rule, ends with a thread. You can use the drive instead of the American one - but this option has already become obsolete.

On large highways, a valve or gate valve is usually mounted at such joints - in this case, a flange connection can be used.

We hope that our article helped the reader understand the intricacies of connecting low-density polyethylene pipes with their own hands. Share useful information with friends and acquaintances on social networks, invite friends and subscribe to our newsletter yourself - and you will always be fully armed to begin any home repairs.

Clamping flanges are ordinary flat fastening rings (HDPE flanges), manufactured according to GOST 12820-80, the inner diameter of which is bored to the required size. The mounting holes are evenly spaced around the circumference of the flange. The main application of pressure flanges is found in polyethylene (PE) pipelines, where they are used to connect HDPE pipes to each other, as well as to connect polymer pipes to metal, connections to pipes industrial equipment, shut-off valves, etc.

Initially, all clamping flanges are manufactured according to unified standard, but then they are bored, acquiring different internal diameters. The size of the required diameter is determined depending on the size of the polyethylene sleeve that will be used together with this flange. The bored flange is placed on a sleeve, the end of which is welded to the end of the pipe. Installation carried out in this way makes it possible to achieve particularly high strength connections. In this case, the flange ideally attaches to a pipe of any size, and all its other parameters - the number of holes and their diameter, center-to-center distance - fully correspond to flat welded flanges made in accordance with GOST 12820-80. Pressure boring flanges for HDPE pipes come in several types - for pipes with a maximum operating pressure of 6, 10, 16 and 25 atmospheres. The clamping flanges presented in our catalog are made of high-quality steel ST20 (steel 20) with an anti-corrosion coating applied to it, which ensures the durability of the products and resistance to the external environment.

All flanges from the price list IN STOCK on our !

Price list “Clamping flanges for polyethylene (PE) pipes RU 10”

When installing PE pipelines, for joining them together or for installing fittings, flanges for polyethylene pipes are used.

This part is capable of providing the most reliable, durable and leak-tight flange connection.

Contents of the article

Part Features

The fixing fitting for PE and PVC pipes is a flat disk with equally spaced holes for bolts. This product is installed together with a collar or bushing.

Types of products

The main parameters by which flange products for PE and PVC pipes are characterized are the internal diameter, external dimensions, weight and working pressure.

Depending on what tasks these parts perform, The following types of adapters exist:

• adapter with special welded bushings;
• slip-on metal flange;
• free-type flange adapter supported by a straight or tapered collar.

The best way to connect light and medium PE pipes with a diameter of no more than 150 mm and light pipes with a diameter of up to 300 mm is a loose flange supported by a straight collar. A loose flange with a tapered collar is used for fittings with a diameter of more than 200 mm.

Characteristics of the fixing flange for polyethylene pipes (video)

Advantages and disadvantages of a flange for PE and PVC pipes

The clamping steel loose flange adapter has several advantages over other parts, which makes it more popular to use. The main ones are as follows:

1. The adapter allows you to install PE in a metal line, which also makes the repair of such systems more accessible.
2. To install the flange there is no need to use any special tools or spend a lot of time: wrench and a little skill allows you to install the part without any problems.
3. Also, the clamping flange adapter has the ability to compensate for the process of compression and extension of the axis and this is Allows you to simplify the process of installation and operation, and reduce installation time.

As for the disadvantages, the most significant is the fact that the gasket that ensures a tight fit is destroyed. This occurs due to the fact that they are clamped as tightly as possible, and this leads to exceeding the tensile strength of the material.

Structurally, the most unsuccessful in this regard, since it cannot protect the gasket from deformation.

Those product models in which gaskets are provided in some recesses are considered more protected from gasket rupture, however, they do not provide full protection, especially with a long service life of the part.

When installing the flange, take into account the fact that When exposed to heat, metal can expand. This causes the fastener elements to elongate more than the adapter itself, which can compromise the seal of the flange connection.

When laying a pipeline from polyethylene pipes, a flange for PE pipes is used to solve problems related to connecting them with each other or with reinforcing elements. What flange fittings are, as well as the features of installing such a connection, are discussed in this article.

Flange - as an element of pipeline fittings

Product Features

Structurally, the fixing flange for PE pipes is a flat ring, or rather a disk, in which holes are located at the same distance. These holes are used to secure the connection using bolts (studs). Flanges are installed together with a collar or sleeve.

The sleeve for the PE flange directly in front of the flange has a special expansion for reinforcement, due to which the flange does not fit tightly against the flange. To solve this problem, bored flanges are used. Such products differ from standard products in that they have an increased (bored) internal diameter to the required size so that the flange fits tightly onto the bushing. All other parameters, such as the number of holes for bolts, their diameter, center-to-center distance, are fully consistent with a standard, flat, steel flange.

Flange Applications

Steel flanges are used to connect polyethylene pipes:

• pressure and non-pressure lines;
• systems designed to remove precipitation;
• storm drainage;
• technical (industrial) pipelines, etc.

Thanks to flanges, it is possible to create a reliable, detachable connection of pipe products with various gate valves, taps (valves) and other pipeline fittings. If necessary, such a connection can be quickly disassembled for repair or cleaning of pipeline products.

Types of flanges

Geometric standard sizes, as well as the manufacturing technology of these products fully meets the requirements state standards. To organize a connection different pipes with fittings and devices, the industry produces a wide range of products. All flanges for polyethylene pipes are characterized by:

• internal diameter;
• external dimensions;
• diameter of bolt holes;
• weight;
• working pressure.

Depending on the tasks performed, the following types of flanges are distinguished:

1. With special welded bushings.
2. Metal caps.
3. Free type, supported by collars, which can be straight or tapered.

For connecting polyethylene pipelines laid with medium and heavy PE pipes having a diameter of no more than 150.0 mm, as well as light pipes, but of large diameter (up to 300.0 mm) the best option there will be loose flanges that rest on a straight shoulder. Free-type flanges, but supported by conical collars, are used for pipes with a diameter of 200.0 mm and more.

Flange connection installation procedure

Due to its simplicity and ease of installation, this type of connection is very common when laying polyethylene pipelines. To obtain a flange connection with welded bushings, you must:

1. Cut the pipe at the planned junction. Ensure that the cut is perfectly straight.
2. Weld a flange adapter for PE pipes (special sleeve) onto the end of the pipe.
3. On the welded bushing using threaded connection install the flange itself.

Flanges should always be carefully inspected before installation for the presence of burrs and sharp elements that could easily cause damage to tubing and fittings.

1. To another section of pipe or other element pipeline fittings Install the counter flange in the same way.
2. After joining, the flanges are fastened together using bolted connections.

To use the slip-on metal flange free type you need:

In both cases it is very important to last stage Tighten the flange bolts evenly in a crosswise manner. The force must comply with the technical documentation.

Thus, a steel flange for PE pipes is a reliable and durable element of pipeline fittings, with which you can mount a sealed, detachable connection of parts (assemblies) of a polyethylene pipeline.