The weak point of any pipeline – connections. No exception and pipes from high density polyethylene (HDPE) is used for water supply and natural gas. Their long and trouble-free operation will provide just the right mix of HDPE pipes, polyethylene because he is strong enough and durable. Types and methods of docking Utilities performed not only polyethylene but also other materials to be joined together. In the process of works performers have to connect the communication of these materials:
• HDPE pipes – each other;
• Connect HDPE pipes with metal sections or fittings;
• implementation of polyethylene joints with highways from other polymers
– Polypropylene and metal plastic.
Depending on the installation conditions and the conveyed fluid (water or gas), as well as to the requirements of building codes selected manner in which the pipe must be connected:
1. Plug flange.
2. The collapsible compound HDPE pipe compression fittings without tools.
3. The one-piece.
Produced by welding parts. For small diameters in the non-critical areas of water pipe connect compression fittings. Joining by welding is suitable for any roaming environment, the size of lines and installation conditions. Exception – HDPE pipe joint with a steel pipe and portions of other polymers. The flanges are placed on the joints of water pipes of large diameter (DN50 and above), gas pipelines, as well as connecting to the shut-off valve. According to the standards connection HDPE pipes under the ground must be performed by welding, and in places of demountable joints need to arrange for water wells. Use compression fittings Fittings – it fittings (elbows, tees, reducers), made of plastic or brass. With their help, join lines simply because they do not require special tools and equipment. On the other hand, the connection pipe HDPE fittings – not the most reliable, it can not be used when laying underground lines followed backfilling the trench. Although, in practice, the owners of private houses buried like joints in the ground under their own responsibility. Norms are not allowed to connect compression fittings engineering networks, lead-in natural gas. Reliable connection with HDPE pipe fitting is carried nut, collet and pressing the clamping ring, sealing provides a rubber sealing ring. Construction of brass fittings is slightly different: the clamping ring, which presses the collet has a slit and sharp notch on the inside. When the nut is tightened notching cuts in plastic, giving an element to move.
Connection Technology HDPE pipe fittings as follows (step by step):
1. Cut a section of a measured length, better pipe cutter for plastic pipes (as an option – so). Usual hacksaw leave burrs, which have to be removed with a sharp knife.
2. The fitting is disassembled, leaving the inside of the rubber ring.
3. Items are put on the pipeline in the order: nut, collet in the form of a cone,
compression ring.
4. Insert the tube into the hole until it stops, to make some efforts.
5. Slide all the parts to a fitting, screw and tighten the nut by hand. Collapsible connection HDPE pipe with a tap or valve through compression fitting, having a mate in the form of thread or flange. The thread tap before tightening should pack linen, and between the flanges of the gasket and pull bolts.

Joining by welding Weld connection methods are the most reliable and durable, although they require equipment and strict observance of technology.
There are 2 methods of welding:
1. butt. The heating elements heat the welding machine ends connectable to a certain temperature, why they are fused into a single monolithic portion.
2. Electrically couplings with built-in heating coil. Performing butt welding, it is necessary to fix the entire structure so that it does not move. It is equally important to maintain a warm-up time in order to get a reliable connection.
Welding and flange connection is made of HDPE pipe, which is soldered to the end of a special sleeve and flange fits over the pipe in advance. Welding areas can be at different angles, if the contractor has sufficient qualifications.
A more convenient way – to make a turn or sidebar using the alloy fittings, designed for soldering. Electrically coupling equipped with its own heating element in the form of a spiral. Compound HDPE pipe is as follows: the bare ends of the pipes are inserted into the sleeve, the contacts of connected wires from the apparatus designed for this type of work. Spiral heat the plastic sleeve to the fusion with HDPE. Warm-up time welding machine defines itself, guided by the bar code on the label of the product. For welding stations running water is important to ensure that their material is the same. You can not cook parts of polyethylene of various brands, such as PE80 and PE100. The joint will fragile, despite the fact that it can go through the primary inspection under pressure. For the same reason perform unacceptable weld pipe HDPE with polypropylene and other polymers. Dock with pipes of different materials transition from plastic to metal – one of the most common compounds. Run it purely on welding is impossible for obvious reasons. Therefore, HDPE pipe connection with a metal pipe produced 2 ways: • Compression molded fitting or threaded; • bolt, tightening flanges. The first option – to small-diameter arteries, where it is possible to cut the outer pipe thread manual Lerke. Then it is screwed an adapter or a compression fitting that is attached to the polyethylene portion. Pipelines in diameter of DN50 and more connected to the flange, and secured by various types of welding. Since the connection to perform HDPE pipes polypropylene water network by welding is unacceptable, can only dock on the thread or flange. Rights Action is the same as the transition metal: diameters up to 50 mm are connected via compression fittings, more than 50 mm – with flanges. Although metal and plastic pipes made of polyethylene, too, can not be welded with products from the IPA. The reason – the different grades of polyethylene and aluminum reinforcement in the walls of the metal-base. Furthermore, their maximum size (DN40) does not allow use for joining the flanges.
Connection pipe with HDPE multilayer system is performed only through compression or weld fitting with internal thread. Mate from metal-base – also fitting, but with an external thread. You can use 2 elements with external thread, connecting them clutch.

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