How to combine a plastic pipe with a metal one. Connection types
At carrying out capital repairs it is quite often necessary to carry out partial or full replacement of water pipes and sewer systems. Due to the high cost of materials, homeowners decide to connect the old metal elements of the pipeline with new plastic pipes. Despite the fundamental difference between these materials in physicochemical characteristics, today there are several options for implementing this idea.
Special fittings will be required to connect the plastic and metal segments of the pipeline
When there is a need for such a combination
The need to connect plastic pipes with metal may arise as in the repair and modernization of existing pipelines, and in the construction of new ones. Experts call such typical cases, in which without such docking can not do:
- uncoordinated actions of different contractors can lead to the installation of elements of communication systems, made of different materials;
- usually, metal terminals of household and industrial equipment are connected to plastic pipes;
- with partial replacement of emergency communications;
- when it is necessary to connect the pipeline to the process equipment, which has a critical temperature for plastic products;
- during the construction of sections of highways, which are exposed to high mechanical and thermal loads.
As you can see, the cause of these cases are various factors. Therefore, the methods of the most reliable connection of pipes directly depend on the purpose and type of pipeline.
Features of application of metal products and polymer pipe products
Properties of any, including metal pipes, determined by the characteristics of the material, used for their manufacture:
- cast iron was used when laying the pipeline not so long ago in Soviet times. It is still considered a fragile material. The cast iron pipe is easy to break with one more or less strong blow. However, products with a relative novelty - High-strength Cast Iron with Spherical Graphite (abbreviated VCHSHG) - the level of impact resistance can be compared with the value of this parameter of the steel pipe;
- steel. This material is subject to corrosion, and on the inner surface of the elements of the pipeline made of it, accumulations of dirt and impurities are formed;
- Stainless Steel. It is still the most expensive metal, employees for many years, but difficult to handle.
- galvanized steel has proven itself in terms of resistance to corrosion, but professionals note the difficulty of installing pipes made of it.
Steel pipes are used for pipeline installation in the modern world, as on durability they practically have no competitors
Plastic elements of pipelines are also divided into several types:
- polypropylene details. Not demanding in care and easy to install. Often purchased material;
- polyethylene are suitable for plumbing, and for laying the sewer;
- PVC products are used for laying sewers of autonomous type;
- metal-plastic pipe products.
Useful to know! Restrictions on the use of PVC pipes are due to the fact, that they do not withstand the circulation of large streams of water.
Types of joints between metal and plastic pipes
Today, there are two ways to perform this procedure:
- Threaded connection. Applies, when connecting pipe products, whose diameter does not exceed 40 mm.
- Flange connection. Optimally with a large cross section of pipes, as tightening the thread in such cases requires considerable physical effort.
Features of threaded connections
To understand, how a plastic pipe is connected to a metal one by a thread, fittings should be studied, used for these purposes. Essentially, such a detail is an adapter. On the other side, to which the metal pipeline will be connected, the fitting has a thread. On the opposite side is a smooth clutch, to which the plastic pipe is soldered. Models are also available, by means of which it is possible to make connections of various highways in greater quantity and fittings for performance of bends and turns.
The threaded coupling is selected depending on the type of plastic pipe - for soldering, with crimp or compression connection
To connect a steel pipe to a polypropylene pipe, you need to follow the following steps:
- remove the coupling with steel communication at the site of its intended connection to the plastic branch of the pipeline. You can also cut a piece of old pipe, apply solid oil or oil and make a new thread with a thread cutter;
- walk on the thread with a rag, fasten a layer of fume tape or rags on top, cover the surface with silicone. Wind on the thread 1-2 turn so, so that the edges of the seal go along their course;
- screw the fitting. Perform this operation with a plastic to metal pipe adapter without using a wrench. Otherwise, the product may crack. If, when you open the tap, leaks will appear, tighten the adapter.
The convenience of the design of this part is, that it simplifies the procedure of connecting metal pipes with polypropylene on turns and bends. Interesting, that if necessary the form of a fitting can be changed. Heat it with a construction blow dryer to a temperature +140?C and provide this part with the required configuration.
Flange connection
As mentioned above, large diameter metal and plastic pipes are connected in a similar way. The final design is collapsible. The technology of such connection of a plastic pipe from a metal without a thread is just as simple, as in the case of a threaded adapter.
- Carefully and evenly cut the pipe at the intended connection;
- put a flange on it and install a rubber gasket. It will act as a sealant;
- Carefully slide the flange onto this sealing element;
- do the same with the other pipe;
- fasten both flanges to each other with bolts.
One of the options for switching from metal to plastic is a flange connection, in this case, the flange is first soldered to the polymer pipe
Council! Tighten the bolts evenly, without displacement of details and without excessive efforts.
Other methods of threadless connection of metal and plastic pipes
To implement such technology, except for flanges, the following devices are also used:
Special coupling. Such a detail is for sale in a building materials store. However, possessing certain skills, you can do it yourself. This adapter consists of the following components:
- housing. It is best to make it from high-strength steel or cast iron;
- two nuts. They are located on both sides of the coupling. If you are going to make such an adapter with your own hands, use bronze or brass to make nuts;
- four metal washers. They are installed in the inner cavity of the coupling;
- rubber gaskets. They are used to seal the connection. It is impossible to specify their exact number in advance.
The diameter of the gaskets, washers and nuts must meet the parameters of the elements of the pipeline. Make the connection of a metal pipe from a plastic one without a thread with the help of such a coupling in the following sequence:
- Insert the ends of the pipes through the nuts to the middle of the coupling. in addition, push the pipe products through the gaskets and washers.
- Tighten the nuts as far as they will go. The gaskets must be squeezed.
The connection is durable and strong enough.
With a Gebo fitting, connections can be made quickly and effortlessly, the main thing is to choose the right diameter
Gebo fitting. This detail consists of the following elements:
- housing;
- nuts;
- clamping rings;
- clamping rings;
- sealing rings.
The connection is very simple.
- Unscrew the coupling completely.
- Put all the above elements on the end of the connecting pipes.
- Secure the joint with nuts.
How to connect a metal-plastic pipe with polypropylene
These products have recently become increasingly popular in the construction of life support systems in a country cottage. Polypropylene pipes are connected to the metal-plastic line of gas columns, washing machines, boilers, etc.. A special coupling-adapter is used for this purpose. And if the connection of polypropylene pipe products with a plastic fitting is made by welding or soldering, then metal-plastic pipes can be simply wound on shaped details.
American is the most popular type of fitting for connecting metal pipes with polypropylene
Useful to know! This technical solution is determined by the design of the fitting: on the one hand, this part is made of polypropylene - for connection with polymer products, and on the other metal - for connection to metal-plastic.
Today, the following fittings are used to connect metal-plastic pipes to polypropylene pipes:
- plastic coupling-adapter with metal internal thread;
- plastic coupling-adapter with external thread;
- tee adapter plastic with a female thread;
- tee adapter plastic with an external carving;
- plastic square (water socket) with female thread. Used as an adapter to connect the faucet.
Specialized trade organizations offer many options for solving the problem of joining metal and polymer pipes. Successful work depends not only on the correct choice, but also from the ability to work with tools and materials. Therefore, carrying out the installation, follow the rules developed over the years and listen to the recommendations of experienced plumbers, perform operations accurately and efficiently. Only then do you not have the results of the work done, neither will your loved ones have any complaints.
