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Connecting reinforcement for low pressure polyethylene pipes

PND (low pressure polyethylene pipes) are one of the most modern and popular products for the construction of various destination pipelines. In turn, each of them has an entrance and exit, and almost everyone has different shut-off valves and branches, respectively, for this we need and fittings for PND pipes.

Types of polyethylene pipes depending on the destination.

There are a large set for PND pipes, which can be divided according to the principle of dusting with the product. How to understand this manifold and how is the correctly selected by one or another shut-off fittings?

All types of PND connections are divided:

• by hardness: rigid and non-rigid (elastic) compound;
• on the unit: detachable and inline connection;
• by the method of performing the connection.

When installing fittings for PND pipes, including shut-off valves, can be docked with pipeline in various ways.

Incomponable connection

Welding is the main type of connection. There are various ways for welding products. Some of these methods are more common, some are applied less often.

Scheme of butt welding.

Welding methods:

1. Butter welding is the most common way when the product end and fitting is melted with a special device and they are pressed together, a monolithic seam is formed as a result of the melt, which is similar in its properties of the pipe material. For this method, fittings and PND pipes must have the same diameter. Jump welding is very often used when building internal water supply and heat supply networks, while "manual irons" apply. If the product is fixed in the welding machine with a special accuracy relative to the place of dusting, then when performing work manually, it is necessary to pay special attention to the mutual location of the products, and the best thing is to froze the seam to fix them with any devices.
2. Nest welding - has the same principle, except that the fittings for PND pipes with an inner diameter are used in this method, which is equal to the outer diameter of the product. If in the first method (welding of the jack) the soldering iron is made in the form of a disk, then with the nesting welding one side of the soldering iron is flat and equal to the diameter of the pipe, the other side has a view of the rod, the diameter of which is equal to the inner feeding diameter.
3. Edge (Pressing) Welding - is used mainly to weld the product with the inputs of wells, etc., where it is necessary to weld the pipe to the plane, which in its size exceeds its diameter. For this, special PE electrodes are used. This method is applied only in a non-pressure system that does not require absolute tightness.
4. Electrical welding - the process of welding consists in melting polyethylene, while fittings and PND pipes should also have the same diameter. However, this method requires the use of a special coupling. The coupling has a heating grid and two contacts in production. Each such coupling has a barcode. If an automatic welding machine is used, it reads the data independently and sets the optimal parameters of the welding. Otherwise, these parameters need to be set manually.

Scheme of electrical welding.

Connect connection

Based on the fact that all welded fittings belong to all-in-disposal compounds, the shut-off valves and control devices are not installed with their use. Since in the case of the release of these devices, with a deline connection, their replacement requires considerable effort.

The next type of connection is. They are used, as a rule, on external networks and the principle of their action are the same. The compression fitting has a ring (cut) and a protracted nut.

Flange compound - used, as a rule, for with a large diameter, in places where the shut-off and other fittings are installed.

Nut, then we dress the ring on the product, after which we tighten the nut. After it is tightened, this compound ensures the impossibility of slipping the ends of the product during stretching effects. In today's market, manufacturers offer both brass and compression type. As a rule, it is used in the threat of shock loads to this compound.

Based on these manufacturers, compression fittings are designed for the pressure of the working medium to 20 atmospheres, that is, they are suitable for applying them in pressure networks.

Flange compound - used, as a rule, for piping pipes with a large diameter, in places where the shut-off and other fittings are installed, or when the pipeline is connected from polyethylene with metal sections. At the same time, the flanges are usually used in polyethylene networks, and, if necessary, the transition to metal is brass fittings equipped with a plastic tap, which is designed for a welded compound with a polymer product.

The threaded connection is used outdoor, which is cast on one of the end of the pipe, and internal - on another pipe connections or fitting. This compound is considered not particularly reliable. Based on this, it is used for the installation of non-pressure fluid transportation systems or in the cable communications laying.

The pipe compound is based on fixing the end with the standard diameter of one product, inside the expansion at the end of another product or fitting. As a rule, this compound is applied when installing a non-pressure drainage system (sewage) or when laying a cable.

Varieties of fittings

For laying a pipeline from, fittings are applied in the following cases (by material and type):

Variety of fittings for detachable pipe connections PND

1. Coupling Equipment - produced with the same diameter from both ends. Used to dust individual pieces of pipe or with other elements with the same diameter size as the pipe.
2. Compensation clutch - It is used to possibly change the diameters of the pipeline or installing an element with a large / smaller size
3. Compound carving plastic. When docked, for example, polymer and metal reinforcement, a combined fitting is performed. A mortgage element with an external or internal thread is mounted in the plastic sleeve, it is usually made from brass.
4. Flanges are used for mounting removable reinforcement or dusting with pipes from other materials. There are combined and PE. Flange couplings are their variety.
5. Tires. Of course, polyethylene is pretty flexible material, but still it is impossible to allow too sharp bends. The use of taps allows the pipeline to significantly change the direction. According to the standard there are bends for taps at 45 °, 66 ° and 90 °.
6. Crosses and tees - with the use of such fittings, the pipeline can be counted with the necessary number of other sections of the network. Branch can be both with the same and characterized diameter.
7. Plugs. This type of fitting allows you to preserve the "deaf" PND pipes. Such a situation may be, for example,, if necessary, to derive a certain section of the water supply, or you can apply in places where the new connection will be organized later, etc.

In general, and fittings to it allows you to create a combination that will make it possible to build a pipeline for any task and in any conditions. Along with a relatively low price and high operational properties of PND products, it provides a polymeric material well-deserved popularity, both in private consumers and in the assembly organizations.

Currently, when laying communication lines of various purposes, low pressure polyethylene pipes (PND) are often used. Their installation is carried out using special fittings, which include ball valves. Next, we will look at what the product data is what they are and what their features are.

Polyethylene ball crane 25 - 25 mm

FEATURES OF BALL CAONS PND

Plastic ball valves for PND pipes are a shut-off valve, which is designed for the complete overlap of the flow of the fluid being transported through the pipeline. They are called ball for the reason that the locking mechanism is made in the shape of a ball with a through hole.

The ball can rotate in the case 90 degrees, which allows you to open or overlap the passage. Management of the position of the shut-off mechanism is carried out using the lever. In large diameter (150 mm and greater), the control mechanism is controlled by an electric, pneumatic or hydraulic drive.

The case of these devices is made of PND, i.e. The same material as the pipeline itself. The locking mechanism most often producers are made from polypropylene or other type of plastic.

Dignity

The shut-off valves under consideration has many positive qualities, among which you can allocate:

• Durability - the product can serve 25 years and even more. Durability largely depends on the operating conditions of the product.
• Reliability, which is associated with the simplicity of the design.
• Low price thanks to the cheapness of materials.
• Minor weight of products.
• High degree of tightness.
• Due to the fact that the device is made of plastic, it is not subject to corrosion, besides, it practically does not settle the precipitate.

disadvantages

For objectivity, we give both the shortcomings of the device under consideration:

• You can not use to adjust the flow, since in this case they quickly fail.
• Like other fittings from the PND, are calculated for less pressure than metallic.
• With increasing temperature, the strength of the device decreases.

Note!
Before using a plastic ball valve for PND pipes, you need to make sure that its characteristics meet the conditions in which it will be operated.

Types of shut-off reinforcement for PND

In addition to the fact that the device in question differ in diameter, they can also be intended for different installation methods:

• Collet (compression);
• Flange;
• Welded.

Below more for more information with the features of devices of each species.

Collet

These devices are used for small diameter pipelines - 20 mm - 110 mm. The main feature is the simplicity of installation, which can be performed with your own hands without using special equipment, and not possessing the skills of such work.

Note!
For high-quality installation of the crane, the collet method must be strictly perpendicular to their axis and remove the champions several millimeters, as shown in the scheme above.

As a rule, this shut-off valve is used in domestic water supply systems. Below are the main characteristics of these devices:

Depending on the device model, the characteristics may differ slightly. However, in general, they correspond to data from the table.

It must be said that compression cranes may have both the same dimensions of the incoming and outgoing nozzle, for example, 32 - 32 mm and different, i.e. Can serve as adapters between pipes of different diameters.

In the photo - flange polyethylene crane

Flange

Flange balls PND valves are used for large diameter pipelines (up to 315 mm). The connection of them with the pipeline is carried out by a bolted method with the help of flanges. As a collet, this connection is collapsible.

Unlike previous type devices, flange shut-off valves can withstand greater pressure. Often this shut-off valve is used in the chemical industry, since they are resistant to the effects of acids and alkalis, and are also not subject to corrosion.

Weld

This connection method is applied in cases where it is necessary to ensure tightness. Instructions for making installation in this case are more complex.

Welding can be performed in two ways:

• Jack - using a special welding machine that melts the ends of two welded parts. Subsequently, the details are docked under pressure.
• Electromefit method - Heating surfaces of the connected parts in this case is carried out using the shaped parts through which the metal spiral passes. As a result, the connectable parts and the electromapht are welded with each other, providing a reliable connection.

Here, perhaps, all kinds of polyethylene ball cranes.

Output

Polyethylene ball valves are a reliable locking reinforcement used for various types of pipelines from PND pipes. As we found out, depending on the purpose of the highway and its diameter, they can be mounted in different ways.

From the video in this article you can emphasize some additional information on this topic.

Polyethylene compression fittings are crimp couplings of a compression type for mounting polyethylene pipes of PE 8 grade and PE 100. Compression fittings for injection molding from polypropylene copolymer. Polyethylene compression fittings are made with internal and external threads of various forms: compression couplings, compression tees, compression taps of ionized compression taps, compression plugs and flange compression compression compression connections.

PND compression fittings are made with a diameter of 16 mm to 110 mm and with a working pressure from 10 to 16 atmospheres (BAR): for diameter from 16 to 63 mm to 16 bar, for diameter from 75 to 110 mm to 12.5 Bar. PND compression fittings are connected to PE pipes using a crimp fitting ring, which is pressed on a pipe. Compression fitting for polyethylene pipes is a collapsible design, which consists of modular components.

Areas of use

PND compression fittings are designed to connect and install polyethylene PE80 and PE100 brands in place changes: turns and branching, in places change the diameter of the pipeline, in places of connection with pipeline reinforcement, as well as for switching from polyethylene pipes to pipes from other materials. Compression fittings for applied during installation and repair of PE80 and PE100 brands, which are used in drinking and technical water supply systems (pipelines transporting drinking and edible water, technical water in irrigation systems, etc.), as sealed cable channels. Also, these fittings can be used in any pipelines with a working medium, with respect to which the chemical resistance of the compression fittings themselves is provided. Very widespread polyethylene compression fittings are used in automatic irrigation systems.

The use of compression fittings made of low-pressure polyethylene provides complete tightness between the mounted items. Installation of compression fittings of PND small diameters is made in manual without the use of special tools, large diameters with a special compression key. Use compression fittings for PE polyethylene pipes under all weather conditions and negative temperatures. Store compression is needed in rooms, protecting against direct sunlight.

COMPRESSION FITTING FITTING PND

Compression fitting for polyethylene pipes consists of five elements:

1 -Gay-cover is made from polypropylene copolymer, designed for fixation and crimping, has an internal thread and external grooves for convenient screwing.

2 -Ampressive folding ring is made of polyoxymetiline, prevents movement and squeezing the fixed pipe, as well as spontaneous development.

3 A compressive function is made of polypropylene copolymer, fixes the sealing gasket in the correct steady position and limits its limit compression and the deformation of the pipe.

4 - The laying ring - the gasket is made of nitrile rubber, ensures reliable tightness of the connection with the pipe, even with its beggars.

5 -Corpus compression fitting, is made of polypropylene copolymer, has a trapezoidal thread for nuts and a pipe introduction limiter.

Main advantages

• Easy installation: Installation occurs quickly and without prior preparation of the pipe, since the fittings are supplied ready for installation and do not require special skills and additional equipment.
• Ease of repair: When repairing compression fittings, special skills are not required, additional equipment and welding machine, only a plastic or metal compression key is needed, and the repair itself occurs by replacing the internal components of the compression fitting.
• Multiple disassembly assembly: assembly and disassembly of compression fittings for PND pipes can be carried out repeatedly up to 10 times.
• Corrosion resistance: There are no metal elements in the PND compression fittings
• Hygienic: All parts of compression fittings are made from materials that are suitable for transporting drinking water and food liquids.
• Connection with elements from other materials: PND compression fittings have standard inner and outer threads, so you can mount the prefabricated elements for connecting pipes and fittings from various materials.

Properties and characteristics

Compression fittings for polyethylene PE pipes have high resistance to temperature differences and high resistance to various chemicals. Compression fittings for PND pipes have high wear resistance during the transportation of various liquids and have a service life for more than 50 years.

Due to the wide popularity of various types of polyethylene pipes, the demand for docking elements called fittings increases. PND Fittings for pipes allow installation easily and in a short time. At the moment, enterprises produce many different connections. Fittings for PND pipes are made from various types of polyethylene, copper or brass.

Fittings for PND pipes apply:

• To connect pipes with the same diameter.
• For docking pipes with different diameters.
• For the arrangement of branching provided for in the pipeline scheme.
• For mounting turns of the pipe.
• To install the plug on the PE pipe.
• To connect pipes with different fittings.

Places of PE pipe connections must be:

• Reliable.
• Durable.
• Waterproof.
• Resistant to possible influences of chemical elements.

Fittings classification

Professional pipeline installers distinguish the connection of PND pipe fittings by:

• Mounting method: compression, welded, electrospass.
• Stiffness: flexible and hard.
• LOCATION: DISTRICT AND LOVE.

There is another classification of connecting elements:

• Direct used for docking PND pipes of one diameter.
• Reducing, applied with pipe connections of different diameters.

We will analyze the most detailed first classification of fittings.

Fittings for various ways of connecting pipes

Depending on the selected method of installing the pipeline distinguish:

• welding fittings;
• electric welded connecting elements;
• compression fittings.

Welded connecting elements

Welded fittings can be made in two ways:

1. method of low tide taking place under high pressure (cast fittings);

1. the method of butt welding of small pipe segments (welded fittings).

Welded fittings are produced with a diameter of 63 mm to 315 mm.

This type of fittings is designed to connect pipes with welding. The low cost of welded fittings causes a wide range of their application. Virtually all branches and plugs provided for in the pipeline design can be made with welded connecting elements.

Most often, welded fittings are used in the installation of gas pipelines and systems in which the temperature of the transported fluid does not exceed 40ºС.

Electric welded connecting elements

Electric welded or thermistor's fittings are used to mount the structure of the pipeline in hard-to-reach places, that is, it is impossible to carry out the usual butt welding.

Equipped with heating wire located on connecting parts. Under the influence of temperature, these spirals are heated and melted the polyethylene tube. After cooling, a durable welded seam is obtained.

Compression connecting elements

Compression fittings for PND pipes are designed to connect pipes without welding. Using such butt elements, a detachable connection is obtained.

The fittings of this species consist of:

• polyethylene case;
• sealing rings located in places of compounds;
• clamping rings protecting compounds from mechanical damage;
• sleeve, pressing pipe;
• covers-nut, reliably covering the place of docking.

Produced from various materials. The diameter of the compounds varies from 16 mm to 110 mm.

Features of installation compression fittings

To properly connect pipes or make the necessary branches by compression fittings, you must follow the following instructions:

1. The PND tube and compression fittings are unscrewed into several revolutions.
2. A markup is applied to the pipe, denoting what depth you must enter the pipe in the fitting. Before installation, it is advisable to lubricate the pipe of the pipe, designed for docking, water or light soapy.
3. Before drawn, the pipe is entered into the prepared fitting. For the complete entry of PE pipes in the sealing ring, an effort will be applied. Otherwise, the connection will not be sealed.
4. The cover-nut is dragged to the end of the thread.

With the right installation of compression fittings, a sufficiently durable and hermetic compound is obtained.

Separation of fittings for stiffness of the connection

According to the degree of rigidity, the fittings distinguish:

• Hard. Such compounds completely exclude the possibility of moving pipes.

• Flexible, in which the longitudinal movement of pipes is allowed to 3 - 5 mm and turn pipes to a small angle. When using flexible fitting, the properties necessary for the connection site are preserved unchanged.

Flexible connections are most acceptable for laying pipelines in the ground, but also more costly. Therefore, they are used only in cases of extreme necessity.

For the installation of the simplest pipelines, hard fittings are more often used.

Types of fittings of the connection discontinuity

When installing the pipeline, it may be necessary for the detachable compounds and all-in-disposition. This is determined by finding the joint and its use. For example, PND pipes for water supply: Fittings At the first stage of installation are used to connect the pipeline with a pumping station. At some point in time, it may be necessary to replace the pump and the detachable connection will simplify the necessary work as much as possible.

Connect connections

In most cases, installation is carried out with the compression fittings described above. But there are other ways to arrange such a joint:

• Flange connection. A cast or brass flange joins the pipe with welding. This type of compound is primarily used for large diameter pipes or docking of a polyethylene tube with a metal.
• Threaded connection. The fastening of pipes is carried out with the help of a thread prepared on pipes and fittings. It is considered the least reliable. It can be used for laying cable pipelines or systems with low fluid pressure.
• Sneaker connection. It is extremely rare. It is carried out by fixing one end of the pipe in the expansion of the fitting or the other end of the pipe. Most often applied to cable pipelines.

For split connections, brass fittings for PND pipes can be used.

Dear connections

Local compounds are most often used to connect structures underground or in concrete, as this species is considered the most reliable. Pipe welding can be carried out in the following ways:

• Job. The most common way to dock the pipes of the same diameter;
• Nest welding. For such a method of docking pipes, fittings are used with an internal diameter equal to a similar tube parameter.
• Pressing or edge welding. It is used to dock pipes with structures, such as wells.
• Electrofuzion welding. It occurs with the help of an electromatic and is considered the most reliable method of compound.

For the arrangement of an incomplete connection, cast and electric welded fittings are used.

Types of fittings

All fittings differ in their constructive features and, accordingly, the area of \u200b\u200bapplication. Depending on this, fittings can be divided into:

• Couplings that are found three main species:
  • Equipment connecting pipes with the same diameter.
  • Compensation, preferably used to transition to a pipe with a smaller diameter.
  • Flange, used for docking pipes having a large diameter.
• Adapters. With their help, it is joined to the pipeline various fittings or another type of pipe, for example, metal.
• Tires. Used to change the direction of pipes, the rotation of the system. Standard taps are produced with a rotation capacity by 45º, 66º or 90º. Some firms are engaged in the production of fittings by customer parameters. If the system is required to install the system with another degree of the angle, then such a fitting can always be ordered from manufacturers.
• Saddles. Designed to arrange various branching. The saddle on the PND pipe can be two types:

• Clamps, crimping pipes from all sides.
• The lining used to embed a new pipeline into an existing system.

• Crosses and tees. Apply to the installation of branches of the pipeline and to connect to the network of other devices.
• Plugs. Used to temporarily overlap the incoming fluid or gas into the pipe.

A certain type of fitting is intended for mounting a specific pipeline design.

Fittings are available to facilitate the assembly of polyethylene pipes. The correctly selected set of connecting elements will minimize the time required for the installation of the pipeline system and will greatly facilitate the operation on the pipe connection.