How to connect the hdpe pipe

Today in the market of pipes one of the leaders are products from polymeric materials. Polyethylene pipelines have significant advantages over products of identical purpose. These pipes are more in demand than steel and brass, copper and galvanized, PVC and metal-plastic. HDPE pipes are used to transport liquids of the most diverse composition. They are not heavy, flexible, easy to install. In addition, they can be interconnected in pipelines using many available methods. In this article we will talk about how to connect the HDPE pipe.

Methods for connecting HDPE pipes

Connection of HDPE pipes is practically performed in two ways. The first method can be divided into:

• butt welding;
• electrofusion welding. 

The second method involves: 

• coupling connection;
• compression fitting connection. 

Tip! When equipping self-flowing pipelines, a plug-in connection is widely used, since the works on its design are relatively quick and simple. If the pipeline is designed to work under pressure, a welded joint is recommended.

Execution of detachable connections

Since the sewer pipelines are pressure-free, their connections are underrepresented compared to the plumbing. They are divided into:

• socket connections, in which the smooth end of one pipeline leads to the socket of another structural element. The tightness of the connection is provided by silicone or rubber cuffs with elastic properties;
• fittings that connect the two ends of pipelines with a special fitting, called a fitting.

Coupling connection 

Coupled joints made of polyethylene using the extrusion method are widely used in the installation of pipelines. With the help of coupling joints, pipe ends can be connected quickly, reliably and without unnecessary equipment.

This connection method has the following advantages: 

• high resistance to mechanical stress and temperature extremes;
• reliability of connecting fastening and durability of pipelines;
• wide scope of use. This connecting type is used when equipping pipelines of virtually the most diverse purposes;
• low cost of polyethylene fittings. 

For installation of pipelines the following coupling types are used: 

• Compression couplings that are available with internal and external threads. Such connecting elements are used for installation of water and gas supply systems.
• Couplings, which are the simplest - connect the ends of pipelines with the same diameters.
• Reducing sleeves that are transient when attaching pipeline elements with different diameters. 

Compression fittings 

With the help of compression fittings, connecting polyethylene pipes is quite easy. This mount is performed in the following order: 

• The fitting is disassembled with a cap nut twisting.
• The end of the pipe is being prepared for joining, namely: the contaminants are removed, the chamfer is removed in diameter, for which a bevel cutter or a sharp construction knife is used.
• On the pipe mark the depth of the entrance of the pipe in the fitting.
• Before you push the pipe into the fitting, to facilitate this work, it is rubbed with a silicone lubricant or ordinary wet soap.
• After the pipe has been force-fed into the fitting to the desired depth, the union nut is tightened back. 

Tip! The nut must be tightened only with your hands, as when using a wrench, you can overdo it.

Execution of permanent connections

At installation of pressure pipelines the welded joints of one-piece type are the most acceptable. It is easy to mount them and with this operation there is no special qualification required.

Butt Welding

Now let's talk about the connection of HDPE pipes using butt welding. To do this, you need to purchase a special soldering iron used in working with plastic pipes. Since it costs little money, it does not require significant financial expenses - professional craftsmen will cost much more. Works are performed in the following order: 

• in the clamping paws of the welding machine, the ends of the pipelines are fixed, which will be welded, and the alignment is carried out;
• the surfaces are heated to the initial melting;
• soldering iron is removed, and molten surfaces are compressed between themselves;
• Next comes the natural cooling of the formed seam. 

Electrofusion welding 

This method is not much more complicated than the previous one, but requires the use of special couplings with inserted electrical coils that heat the cell when the voltage is applied. As a result, the connection elements are welded to the surface of the coupling. For the welding process to proceed normally, you need: 

• pre-strip the ends of the welded pipes,
• ensure the static state of the parts of the joint during welding. 

The advantage of this method of connection is the simplicity of the work performed. Tangible minus - the high cost of electrical couplings. If you plan a large number of connections, it is better to use resistance welding.

Connection with metal pipes

To connect pipes made of polyethylene and metal, use two methods of connection: 

• Threaded connections for pipes with a small diameter. In this case, you need to buy special-purpose fittings, which, on the one hand, should have threaded threads for joining with a metal pipe, on the other hand, a perfect smoothness coupling for fastening with the HDPE pipe.
• Flange connection for large diameter pipes. In this case, flanged sleeves are welded to the polyethylene pipes, which make it possible to use an additional flange on its surface, which is tightened to the flange of the metal pipe with the help of studs and nuts.

In order to choose the right connection, you need to compare all the pros and cons of each, watch a video about how the HDPE pipes are connected, make a trial attempt, and you can start the main work. 

Video

From this video you will learn how to install the compression coupling: