Connecting fittings for HDPE pipes. Connecting HDPE pipes with fittings - features of the work. Flange connections and transition to metal

Currently, the leaders in the pipe market are products manufactured using polymer materials. Significant advantages distinguish HDPE water supply from similar products. These pipes are more in demand compared to brass, copper and galvanized, PVC and metal-plastic. The use of HDPE pipes is possible for a wide variety of liquids. They are quite lightweight, flexible and easy to install. They can also be connected into a pipeline by any available method.

Flexible polyethylene pipe appeared more than 2 decades ago.

The meaning of the abbreviation HDPE means that pipes are made of polyethylene under low pressure.

Basically, grades such as PE 80 and 100 are used for their production.

The main advantage of such water flows is the flexible material and minimum costs for installation work. You do not need to have special skills to install such a structure.

HDPE pipes do not corrode, they can be laid without digging special trenches, they are quite resistant to soil displacement, they weigh little, and they are resistant to aggressive environmental influences.

HDPE pipe can be used for laying communication cables both indoors and underground. It protects the cable from possible damage during operation. Can also be used to lay power lines. These pipes do an excellent job of protecting communications from mechanical damage, stray current, and also from soil influences.

The service life of such a water supply system can exceed fifty years.

For underground installation the following types of HDPE pipes are used:

  • lightweight HDPE corrugated pipe;
  • double wall HDPE pipe;
  • HDPE pipe smooth;
  • smooth-walled rigid pipe;
  • Heavy corrugated pipe.

Characteristics

The corrugated pipe is reinforced with steel wire, which makes it more durable.


The inner shell of double-walled products can be smooth from LDPE and corrugated from HDPE. Thanks to this design, the pipe has high ring rigidity and can withstand heavy loads.

The double-walled HDPE pipe has a smooth inner surface, which greatly facilitates installation work for the cable.

HDPE pipe can be used for installation work even in severe frosts.

Each product has its own characteristics and has its own diameter.

For example, a pipe HDPE 63 has greater resistance to bacteria than others.

Another type of pipe - HDPE pipe 110 mm- frost-resistant, does not require additional insulation measures.

HDPE pipe 160 mounted using polyethylene fings.

HDPE pipes 32 mainly connected using welding. It must be taken into account that the HDPE pipe 50 or another size must be of the same brand.


 Individual sections of the hydraulic main can be connected in 2 ways:

  • sectional;
  • one-piece.

Permanent connection method more often used if it is planned to supply water into it under pressure.

Pipeline fragments are secured by mechanical or electro-hydraulic welding.


When installing a gravity system, it creates detachable pipelines. For example, in a sewer where water does not flow under pressure. The dismountable method is also used when assembling devices with a small cross-section.

Detachable pipe connections can be flanged, coupling, or collet-crimp, meaning using fittings.

A fitting in plumbing is a connecting part of a water supply system, installed at joints, at branches, at turns, at the junction of fragments of different diameters.

Also, the installation of connecting parts is carried out at the intended place of repair work, where additional elements are connected or a configuration change is observed.

Varieties of elements

Fittings used to assemble elements into a single network come in different types. Polypropylene is used for their manufacture, and they can also be made of brass.

Based on their application, they are divided into categories:


Most often, the use of these connecting elements is used in collapsible structures, but there are varieties that are used to create an integral network - electric or welded fittings.

Types of fittings

Depending on the design, fittings come in several types:


Methods for connecting polyethylene pipes

HDPE pipes can be connected in 2 ways. The first is divided into:

  • butt welding;
  • electrofusion welding.

The second method involves connection using a coupling and fittings.

There are fewer requirements for sewer pipelines compared to water pipes. This is explained by the fact that they are non-pressure and are divided into:

  • socket connection;
  • fitting connection.

Coupling connection


Coupling connections polyethylene pipes, manufactured by extrusion, are widely used in pipeline installation work. Coupling connections make it possible to quickly, reliably and without any unnecessary devices connect the ends of the pipeline.

Advantages of this connection method:

  • resistant to mechanical stress and temperature changes;
  • fastenings are reliable and durable;
  • wide application;
  • low price of polyethylene materials;

When installing a pipeline, use the following types of couplings:


Compression fitting connection

Compression fittings are used to easily connect polyethylene pipes.

This is done in a certain sequence:


The nut must be tightened exclusively by hand because using spanner there is an opportunity to overdo it.

Pressure pipelines are mounted with welded joints of the one-piece type. Installation is not complicated and does not require special qualifications.

Butt welding

To connect HDPE pipes by butt welding, you will need a special soldering iron.


The work is performed in the following sequence:

  • The ends of the pipe are secured with the paws of the welding machine and alignment is carried out;
  • The surface heats up until melting begins;
  • The molten ends of the pipes are pressed together;
  • The seam is then cooled naturally.

Electrofusion welding


This method is a little more complicated than the method butt welding and will require special couplings with electric spirals, which heat the element when voltage is supplied. The elements are welded to the coupling.

The advantage of this method is the simplicity of the work performed. The downside is the high cost of the electric coupling. If many connecting elements are planned, then it would be more advisable to use resistance welding.

For joining polyethylene and metal pipes two connection methods are used:


Socket connection


Socket connection of HDPE pipes is one of the most economical methods. After all, there is no waste on welding. But this type is only suitable for non-pressure lines. The sockets are not able to properly connect the system under pressure.

To ensure tightness when immersing the bells of one into another, it would be more advisable to use sealing rings, for example rubber ones.

HDPE water pipe – sizes and prices


If you need a HDPE pressure pipe, then it is much thicker than non-pressure products. For example, in the case of gravity sewerage, pipes with SDR values ​​from 26 to 41 are used, and for low-pressure water supply of a low-rise building, pipes with SDR 21-26 are quite suitable.

If there is a need to provide high pressure for a main water supply or to install a sewer pressure collector, the SDR indicators should be no more than nine.

When choosing HDPE pipes for sewer installation, the size and price will depend on the fact that a product with a larger diameter and greater wall thickness will cost more. This also applies to other PE pipes.


The technology for connecting HDPE pipes, in contrast to connecting metal pipelines, can be carried out either by welding or using special parts. And if the tightness of the welding structure is beyond doubt, then the quality of the connection using fittings depends on the correct installation.

HDPE is polyethylene made under low pressure. HDPE is obtained by polymerization of the organic substance ethylene at temperatures up to 120 ͒ C under pressure up to 2 MPa in a solution of a special catalyst. The resulting material is also called high-density polyethylene (HDPE) because it is denser and stronger than other polymers.

Pay attention! Modifications of HDPE are used in the creation of boats, body armor and the construction of hazardous waste processing sites, as well as for the manufacture of pipes. The variety of applications proves that polyethylene low pressure- very durable and airtight material.

Advantages and disadvantages of HDPE pipes

The advantages of HDPE pipes include:

  • Immunity to any kind of solvents. At temperatures up to 80 ͒ C, HDPE pipes do not dissolve at all. When this temperature is reached - only in special solvents. Water is harmful only at temperatures above 180 ͒C.
  • Do not corrode. This problem is known for all metal pipes, which, under the influence of water and air, begin to oxidize over time. HDPE pipes are not susceptible to corrosion because they contain no metals.
  • Smooth inner surface. Roughness and unevenness lead to the accumulation of various types of contaminants. Over time, such dirt can almost completely block the lumen. HDPE pipes are smooth, so nothing interferes with the laminar flow of liquids through them.
  • Durability. Manufacturers promise that their products can last up to 50 years. It is worth considering that this figure was obtained theoretically. High-density polyethylene was introduced into service about 60 years ago, so reliable data on such a service life have not yet been obtained.
  • Flexibility. HDPE pipes are very flexible, they can even be rolled. This is an undeniable advantage if they are laid through uneven terrain.
  • High strength. HDPE is a durable, airtight and at the same time elastic material. It does not leak, does not break or bend. Thanks to their flexibility and strength, they have proven themselves well even in seismically active areas.

Polymer pipes are often used both in industry and in the installation of water supply systems in private construction. Their popularity is due to the ease of installation and low price of the products. The reason for such a low cost is the limitation of the operating temperature of HDPE pipes to 65 degrees. However, the supply of both cold and hot water pipes into a house or apartment are almost always carried out with their help, so connecting such pipes is a fairly pressing issue.

Peculiarities

In addition to pipeline installation, the performance properties of HDPE pipes are reflected in the following areas of application:

  • protection electrical cables And cable systems connections laid in the soil against corrosion;
  • formation of a waterproofing layer for various materials– concrete, metal, wood;
  • installation of irrigation and sewerage systems, as well as gas supply.

Their high popularity is also due to the fact that pipe sections can be connected to each other in several ways, which makes them almost universal.

Species

There are several classifications of such connecting elements for HDPE systems. The main one is the classification according to the method of their installation. All connections of HDPE products can be divided into two types: one-piece and detachable.

Permanent connections can be created either with or without a fitting. However, a connection without an additional element is less reliable and durable, so it is practically not used.

One-piece

Such connections are used quite rarely and are made using special welding, performed either as a conventional butt joint or using an electrofusion joint. In the first case, with the help of professional welding equipment, the ends of the cut products are heated to a soft plastic state, after which they are pressed against each other and cooled in this position until they harden. Such a connection will be strong only if the sections of the two pipes being connected have a round rather than oval cross-section.

To work with an electric coupling, you will also need special equipment that will heat the spiral located in it. Cut pieces of pipe are inserted into both outlets of the coupling, the spiral heats up and melts their connected edges. After the spiral has cooled, the heating apparatus is disconnected from the coupling, and it is left as a connecting element that protects the seam.

Thus, welding of HDPE products can be done end-to-end, by socket welding with a fitting, using a press (edge ​​welding) and using electric couplings.

Detachable

Most often, detachable fasteners are used to connect HDPE products. This is done by the socket alignment method using elastic polymer seals. This method can only be used in non-pressure pipeline systems.

For pipes in which water is supplied under pressure, various fittings are the ideal connection method. Their use increases the service life of the entire system, its reliability and resistance to temperature changes. The fittings are universal and resistant to various aggressive environments. They are used both for connecting hoses with the same internal diameters, and for products of different calibers.

The connection itself may vary.

  • Flanged. In this case, a brass flange or a cast flange is connected to the pipe by welding. Most often, pipes made of different materials or wide lines are connected in this way.
  • Bell-shaped when one end of a pipe fits into an extension of a fitting on another pipe. Systems correctly connected using this method are the most reliable and pressure-resistant.
  • Threaded. With this connection, the threads on the pipes and fittings are pre-tightened with a special tool. Only systems with low pressure can be connected in this way, as this is not a very reliable method.

Taking into account the rigidity of the material, there are flexible and inflexible connections made of metal (brass, steel, cast iron and copper) or polymers (polypropylene, plastic, polyethylene and PVC). Based on the diameter of the hose, the fastening method is divided into connecting pipes of the same size and different ones.

In addition to the connection method, components for HDPE pipes are divided into the following types.

  • Welded. Such elements for HDPE systems are produced either by casting (cast fittings) or by conventional welding of short pieces of pipe (welded fittings). This type of welding is called butt welding. The diameter of the elements ranges from 63 to 315 mm.
  • Electric welded. In essence, such fittings are just thermistor couplings, used where conventional welded joints are impossible to organize or are not reliable enough. One of the features of such electric-welded elements is the ability to carry out work without moving the pipe and creating separate tie-ins into the system. With their help, you can connect hoses of different diameters, since the fittings are available in many different diameters. They come not only in the form of ordinary couplings, but also in the form of tees, bends and plugs with small diameters of 20, 25, 32 mm, and for large systems with diameters 800, 900 and 1200 mm.

This type of product has wide application and is used for installation of any branches and plugs that exist. Most often they are installed in gas supply systems or for liquids with a highest temperature of 40 degrees.

  • Compression (crimp). Such detachable fasteners are available for combining pipes without welding. Compression elements consist of a polyethylene rigid or flexible body with O-rings at the ends, clamping connections, a compression sleeve and cap nuts. The sizes of such fittings start from only 16 mm, and end with the standard diameter of the riser line - 110 mm. Typically, when installing water supply and sewerage systems, fittings with a diameter of 50 mm are used, since inlet and outlet pipes of this particular diameter are installed in most houses and apartments.

In addition to all of the above classifications, the fittings themselves are divided into several types depending on the role they play in the water supply or sewerage system.

  • Plugs - for permanent or temporary closing of the path to the flow of water and gas.
  • The clamps compress and secure the pipe.
  • Tees or crosses - for installing branches from the main pipeline and connecting additional devices.
  • Couplings are elements connecting two sections.
  • Adapters - for assembling pipes from different materials into one system, for example, HDPE with metal.
  • Bends are needed to rotate pipes angularly and change their direction. Standard elbows are available in 45, 56 and 90 degree angles, and can be made to order if a different degree of bend is required.
  • Saddles are used to create branches.
  • New pipes are inserted into the previously installed system using linings.

Installation

Of all the types of connections for polyethylene parts, compression fittings are most often chosen for installation on their own. The choice of this type of components is due to the lack of expensive equipment for their installation. You just need to connect all the parts of such fastening with your bare hands.

The installation process itself is as follows.

  • Pipe cutting. The polyethylene pipe is cut with special scissors at a right angle. The edge must be cleared of all burrs and rounded. A special mark is applied to the surface of the pipe, which shows to what depth the pipe needs to be inserted into the socket of the fitting.
  • Analysis of fastening. Before inserting the ends of the pipe into the polymer connector, it is necessary to loosen and remove their plastic caps. It is strictly prohibited to put the assembled fitting on the end of the pipe, as the parts will be connected incorrectly and there is a high risk of leaks.
  • Compound. The end of the pipe is lubricated with ordinary soap or moistened with water, and the nut removed from the fitting is put on it. A press-fit sleeve is placed on the pipe. Clamp ring white it is installed so that its thick part is directed towards the pipe, and the rubber ring can either be placed in a special recess in the fitting or put on the pipe itself.

The pipe is inserted into the fitting body, the ring and sleeve are moved close to it. The clamping nut is first tightened by hand, and then tightened using a special tool. After installing all connections, it is necessary to check the system by supplying water to it at the maximum permitted pressure.

Installation of water supply using HDPE pipes is quite simple, even beginners can assemble simple system own water supply.

However, there are some typical mistakes, which it is better to know about in advance in order to avoid them.

  • You should not purchase products from different materials. Water supply hoses can be made from polymers different types, which will reduce the tightness of their connection. This could result in a crack or leak near the fitting.
  • A mistake is either excessively tight tightening of the nut or weak fixation. In the first case, you can not only break the thread on the product, but also get a microcrack in the body, invisible at first glance. Once water is introduced into the system, such a crack will begin to expand, and the fitting body will eventually burst. In the second case, the waterproofing ring will not be pressed tightly, and water may seep past the edge of the joint.

In household networks, they usually install the most inexpensive option with manual control. Nevertheless, devices with a gearbox have also become widespread, making it possible to facilitate manual effort when changing the position of the lever. For line widths of 150 mm and above, exclusively mechanical drives are used and are not manually blocked.

Low-density polyethylene occupies a leading position in the popularity ranking among materials used for pipeline assembly. The secret of such demand is easily explained by the versatility of use and ease of installation of polyethylene pipes.

But as when working with any other polymer, high-quality installation of HDPE pipes with your own hands can be done only if strict adherence technologies. We will tell you what nuances to consider when joining elements. We will explain how to correctly bend and straighten them.

Technologically, HDPE pipes can be connected using two main methods – one-piece and detachable.

The first involves the use of , the second is implemented without using it.

Each fastening method has its own advantages and disadvantages, and therefore the optimal option for joining polymer pipes is chosen based on specific conditions

Welded permanent connections provide the possibility of maximum sealing, which is especially important when arranging. Detachable connections are easy to install and make it possible to disassemble the pipeline at any time in order to change the configuration of the main line or add new bends to it.

Permanent connection methods

To join HDPE pipes, two permanent connection methods are used: by butt welding and by installing an electric welding coupling.

In any case, when implementing these methods, the following requirements are imposed on connections:

  • The maximum displacement angle of the welded sections should be no more than 10% relative to the wall thickness of the pipes being joined.
  • The joining seam should be made above the outer level of the surface of the adjacent sections.
  • The height of the bead of a well-made seam should vary in the range of 2.5-5 mm.

The optimal value of the roller height depends on the thickness of the walls of the product being fused. On thin-walled pipes (up to 5 mm) it should be no more than 2.5 mm. If the thickness of the pipe walls varies between 6-20 mm, then the height of the roller should be no more than 5 mm.

By butt welding of pipes

The creation of a permanent connection is carried out by softening the material to the state of a viscous substance so that a diffuse unification of its parts occurs. It is used for pipes with a wall thickness of over 5 mm.

Butt joints using a welding machine are used when constructing pipelines through which liquid is to be transported under high pressure conditions.

The welding connection method is used on straight sections of water pipelines that are supposed to be operated under pressure. Only it allows you to obtain a tight connection with diameters over 200 mm, since it does not create a loss of pipe rigidity, leading to deformation.

Do-it-yourself durable welding of HDPE pipes is carried out using a special tool. The essence of the method is to heat the ends of the joined elements to a viscous state using a heating nozzle. The softened ends are simply connected to each other under pressure, after which the connection area is simply allowed to cool.

The main difficulty in working with equipment is the need to control not only the degree of heating of the elements, but also your own body movements in order not to spoil the seam or compromise the integrity of the pipes

When executing welding work It is important to maintain the temperature conditions of the heating elements.

The parameters of the time delay and temperature of the heating elements are determined taking into account three factors:

  1. Pipeline wall thickness.
  2. Diameter of bends.
  3. Technical parameters of the soldering device.

Connecting pipes by welding is the most reliable and durable option. With its help, you can create a one-piece mount that can withstand both free-flow and pressure pressure.

The main advantage of welding fasteners is reliability, which cannot be achieved when using the cold pressing method. The only “disadvantages” of the welding method include the inability to disassemble the connection for carrying out preventive maintenance and cleaning the same pipe

Welding is performed in the following sequence:

  1. The communication is trimmed to the specified size. The parallelism of the plane of the ends is adjusted. The ends are cleaned with a piece of sandpaper.
  2. A chamfer 2-3 mm wide is removed from the ends. The welding site is thoroughly cleaned and treated with a degreasing compound.
  3. The soldering iron is set to the heating mark of 260°. While it is warming up, string the welding nozzles and wait until their degree of heating reaches the set temperature.
  4. Using a centering mechanism, the fitting and the end of the pipe are buried in the cavity of the nozzle. If the soldering iron does not have a centering mechanism, the alignment will have to be checked “by eye,” making the alignment as accurate as possible.
  5. The centered elements are pushed in to the specified mark, connecting under pressure, and the time specified in the instructions is maintained for melting.
  6. After completion of work, the device is moved to the side and disconnected from the network. The welding area is fixed in a given position without displacement or rotation until the surface is completely cooled.

When welding, it is important not to overexert it. This can provoke the formation of an influx of polyethylene onto the inner diameter of the product.

Video #3. Pipe straightening option:

When choosing a method for connecting and aligning polyethylene pipes, you need to take into account the pressure level of the working environment. This will minimize the negative impact of manipulations with the pipeline on its technical characteristics.

Hello dear reader! If you need to lay a pipeline cold water, you can use inexpensive and practical material. Each material has its own subtleties and installation features. In this article we will tell readers how to connect a HDPE pipe.

Polyethylene is a widespread and well-known plastic. But pipes from it began to be made not too long ago - about 50 years ago. The name "low-density polyethylene" comes from the method of production of polyethylene and has nothing to do with the quality of the plastic.

Pipes can be black, bright blue, black with blue and yellow stripes, gray (for sewerage), and rarely other colors. For water supply drinking water blue or black with blue stripes products are intended, black products are for technical purposes. Diameters – from 16 to 1600 mm. Manufactured as measured products 12 m long or in coils (if the diameter does not exceed 160 mm)

Scope of application

HDPE is used exclusively, as it can be operated at a temperature of no more than 40 °C. Working pressure – no more than 20 MPa (2 atmospheres). They are used everywhere for laying water supply and sewerage networks underground and water supply systems from a well with a pump.

Wider distribution is hampered by instability to ultraviolet radiation– it will not be possible to completely switch to HDPE.

In addition, communication or power supply cables are laid in smooth or corrugated tubes.

Advantages and disadvantages of these pipes:

Advantages

  • low cost;
  • chemical inertness - does not react with alkalis or acids; the water does not acquire any foreign taste or smell;
  • corrosion resistance; resistance to aggressive environments;
  • durability - the first pipes have been in service for more than fifty years;
  • smooth inner surface - such pipes do not “overgrow” with calcium salts, like metal ones;
  • tolerate freezing with water inside and do not burst like metal ones;
  • are not afraid of temperature changes (ranging from - 20 ° C to 40 ° C):
  • plastic polyethylene easily tolerates soil movements;
  • Manufacturability – easy and quick installation;
  • polyethylene is environmentally friendly - its production and disposal do not lead to environmental pollution;
  • their low weight facilitates their installation, storage, and transportation.

Flaws

  • the most significant drawback is sensitivity to ultraviolet radiation. Water pipelines left in the open sun will begin to deteriorate in just a couple of years. That's why water pipes made of HDPE is used exclusively in underground communications and in rooms with artificial lighting or without light at all (for example, in basements and ground floors no windows);
  • not intended for use with hot media.

Connection methods

Pipes made of low-density polyethylene 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; cleared of burrs;
  • the ends are chamfered (using a 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.

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

Fitting connection

Compression fittings are a type.


Installing them is similar to installing couplings.

Flange connection

Used on main pipelines large diameter(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

The only possible method for connecting large diameters.

Butt welding

It is advisable 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, you should special attention Pay attention to preliminary cleaning of the ends and immobility of the joint until it cools completely.

Requirements for welded joints

  • there cannot be any depression at the seam site - only a protruding roller;
  • the displacement of the ends relative to each other should not exceed 10% of the pipe wall thickness;
  • with a wall thickness of up to 5 mm, the thickness of the roller should not be more than 2.5 mm; for wall thickness - no more than 5 mm.

Step-by-step instructions for connecting HDPE pipes

Required tools and materials

  • centralizer;
  • hydraulic unit;
  • heater with temperature control;
  • electric trimmer;
  • inserts for various diameters of welded products.

Work progress

  • HDPE pipes are clamped in a centering device;
  • trimming and chamfering is carried out;
  • the ends are degreased;
  • surfaces are heated by a welding heater and melted;
  • the welding heater is removed;
  • the ends are compressed so that a seam bead is formed;
  • the pipes are not touched until completely cooled, then the centralizer is removed.

Connection video

It is always better to see the production process of any work. Our video will help you see all the intricacies of the process of welding PVC pipes.

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

After welding in mandatory 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. The ends to be connected should be welded or put on with internal threaded couplings (couplings with internal threads) made of the appropriate material, and a quick-release fastener should be screwed onto one threaded connection(“American”), then use a union nut to connect two MREs.

How to join polyethylene and steel pipes

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