What purge? What for? Is the pipe dirty? What is there to clean, is it even?

In order not to ask these and many other questions to experienced installers, causing them to smile condescendingly, let's try to figure out for ourselves when and why it is necessary - cleaning for polypropylene pipes.

Reinforcement

Polypropylene is a material that has a lot of advantages, but along with them, there are some features. When choosing it for a home, primarily for hot water and heating systems, they must be taken into account.

There are two main points to remember:

• Limited from above by 95 degrees working temperature . Although, according to current standards, the water temperature in engineering systems apartment building and is limited to the same 95 C, in fact, under certain circumstances, this value can be exceeded. It's more of a force majeure, but it happens.
• Large coefficient of thermal expansion. The flexibility of polypropylene makes it possible to compensate for thermal expansion to a large extent, but there are situations when any displacement of the pipe is undesirable.
  Let's take at least the laying of a polypropylene pipe under a screed or plaster.

Reinforcement completely solves the second problem and partly the first. almost does not expand when heated. In addition, at the temperature at which it begins to soften, the reinforcement will keep it from deforming.

Tip: do not rely entirely on reinforcement and put polypropylene, say, on the supply water supply elevator node in Siberia, where the temperature of the coolant in winter can exceed well over a hundred.

At a minimum, connections with fittings, when softened, may not withstand pressure.

Types of reinforcement

Two materials are usually used as fittings for polypropylene pipes:

• Aluminium foil- a layer of aluminum with a thickness of 0.1 to 0.5 mm, located outside the pipe or inside it, between the layers of polypropylene. The method of its connection with polypropylene is glue; it can be solid or perforated.
• fiberglass mesh. To be precise, fiberglass reinforced pipes are a three-layer structure, where the inner and outer layers are polypropylene, and the middle layer is a mixture of polypropylene and fiberglass.

Well, where does the cleaning of polypropylene pipes?

The fact is that if your polypropylene pipes are reinforced with aluminum, then before welding with a fitting, aluminum foil must be removed from the junction.

Why cleanup is needed

outer reinforcement layer

In case the aluminum foil is the outer shell, everything is clear. The very principle of connecting a pipe with a fitting implies that not only the inner surface of the fitting, but also the outside of the pipe must be melted; polypropylene melt will weld extremely poorly with aluminum. Not to lie.

Internal reinforcement

And if the aluminum layer is inside the pipe? He will not be in contact with the welding site.

In this case, the removal of aluminum is necessary so that aluminum does not come into contact with water. Otherwise, with at least some potential difference inside the heating system, electrochemical processes begin, leading to the gradual destruction of the reinforcing film.

The consequence of this is the stratification of the pipe and a decrease in the strength of the connection as a whole.

Fiberglass

And only here everything is simple: when reinforcing with fiberglass, stripping for polypropylene pipes is not needed. The grid is located inside the pipe; it does not come into contact with the inner surface of the fitting; not afraid of water.

Tools

The tool for stripping polypropylene pipes can be divided into two main categories:

• Manual stripping;
• Drill bits.

The former often have handles (removable or non-removable) that make the use of the tool more convenient.

The latter can be equally clamped into a drill chuck or installed instead of a drill into a puncher (of course, with the impact mode turned off).

Tip: drill bits do not require much effort, but it is more difficult to control the stripping process with them, and polypropylene is a rather soft material.

If you don’t need to clean reinforced pipes dozens of times a day and you haven’t gotten your hands on it yet, it’s better to use a hand tool.

The entire list of tools used by professionals in the installation of polypropylene water pipes is reduced to the following list:

• Roulette;
• Pencil;
• Soldering iron for welding;
• Pipe cutters (compared to a hacksaw or impeller, they give a more even cut; if you only need to mount one home plumbing, they are easy to do without);
• Cleaning tool for polypropylene pipes.

Stripping for the outer layer

Manual strippers to remove the outer layer of aluminum are simple clutches with tool steel knives inside; put on the pipe - turned - ready. They are often made double-sided, allowing you to work with pipes of two different diameters. Of course, such a tool is much more convenient than two different sweeps.

The use of pipes in composite metal structures is very beneficial: pipes give joints increased strength and rigidity, while reducing the mass of the assembly. However, the pairing of pipes with each other is laborious and requires special preparation of the ends. This work can be made easier by using special devices- pipe trimmers.

The principle of operation of the trimmer for metal pipes

The task of the pipe trimmer is to minimize the gaps that inevitably occur when fitting the ends manually, as well as to give the welded joint sufficient aesthetics.

It is known that when connecting and tie-in steel pipes, depending on the angle of their mutual inclination and diameter, the mutual conjugation curve can be a parabola, an arc, or even a straight line. Therefore, it is very difficult to perform a successful pairing by analytical calculation. The problem can be solved by spatial 3D modeling using the well-known KOMPAS or AutoCAD programs, but in practice they do things differently.

In serial production, pipe trimming is carried out using milling machine equipped with a dividing head. The method is accurate, but requires appropriate equipment, which is not always available. home master. At the same time, having powerful drill for metal (from 1000 W) and a hole cutter, you can quickly profile the end of any pipe.

Industrial versions of such devices in the special literature are called tube notcher (slot cutters, although they are capable of performing curvilinear contours).

The pipe trimmer includes:

1. Shaft, at one end of which there is seat for a drill chuck, and on the second - a seat for a hole cutter.
2. Bearing assembly, rotating in which, the shaft receives the necessary rigidity.
3. Body, sometimes with a vise for clamping a tubular workpiece.
4. Rotary device, with which the workpiece can be positioned at the desired angle.
5. Adjusting screw.

With the help of the trimmers under consideration, it is possible to mate pipes with a diameter of 6 ... 75 mm, which in most cases is quite enough. The range of change of mating angles is from 45 to 210 0 . It should be noted that the crown cutter is not included in the device.

For processing long pipes, manual pipe trimmers with a chain clamp are used, and for short products, the supporting and guiding parts of the device are combined in one unit. The safety of work is ensured by the presence of retaining rings, which limit the longitudinal movement of the shaft.

The shaft is the most structurally complex element of the trimmer. First, it must receive longitudinal movement as the cutter penetrates the pipe metal. Secondly, during milling, vibrations are created, which are caused by a sharp fluctuation in the torque of the base power tool. Therefore, the shaft is made polished, has a sliding fit of high quality accuracy, and the bearings used are needle type, which allow compensation of axial and radial loads.

The price of such devices is from 8000 to 50000 rubles. At the same time, all pipe trimmers of the TT size range are quite compact devices that are fixed in a cartridge lathe. The electric drill is fixed in the same way. When processing pipes of small diameter, the device can rest directly on the floor of the workshop.

Do-it-yourself pipe trimmer

In the mass production of shaped profiled pipes (for example, in sports auto and motorcycle workshops, or in plumbing repair sites), a manual pipe trimmer can be made independently. For this, the initial scheme of the trimmer, which is shown in the figure, is made under the blanks available to the home master.

The design consists of the following parts:

1. Base in which milled grooves are made for installation jig. In turn, the shape of the base can be adapted to the existing workbench, work table, etc.
2. L-shaped bracket with three longitudinal grooves, the presence of which allows you to fix the pipe in the fixture different diameter.
3. Crawlers with adjusting and clamping screw.
4. Replaceable presser foot.
5. A bracket that presses the foot to the crawler with screws.
6. Bearing unit.
7. A pivot arm that serves as a bearing surface for the bearing assembly.
8. A shaft that does not structurally differ from a similar part of industrial trimmers.

For the manufacture of the shaft, you can use the front shock absorber strut passenger car(for example, VAZ - they are easier to get at a car service). In addition, the steel grade of the shock absorber strut in terms of its strength and performance characteristics fully complies with the rigidity requirements for high-quality trimming of steel (and, especially, aluminum) pipes. The guides of the rack itself are suitable for guiding the shaft: they have a surface wear-resistant coating based on anti-friction alloys. The ends of the rack are naturally subject to additional processing- for mounting in a drill chuck, and for installing a hole cutter.

Needle bearings should be pressed into the guides, the size of which is selected according to the dimensions of the guides. Two bearings installed in the guide from the return cylinders of the decommissioned hydraulic press will provide desired stiffness and parallelism of the main working unit of the trimmer. Bearings are installed simultaneously from both ends of the housing.

The available advice regarding the installation of fluoroplastic guides should be taken with skepticism, since load bearing capacity PTFE is much lower than bearings.

For the manufacture of other elements of a home-made pipe trimmer, you can use shaped rolled products - corners or channels of the appropriate size. Profiling and making grooves are best done on a jig milling machine, thereby guaranteeing their accuracy and parallelism. It is not difficult to make and clamping device, for which a new clamp with the required diameter and length is suitable.

The swivel lever must have sufficient rigidity, so for its manufacture it is necessary to use a strip with a thickness of at least 12 ... 16 mm. On the part of the body where the swivel arm is installed, it is worth applying angular risks, along which it is easier to position the pipe.

Trimmer for polypropylene pipes

The need to process the end elements of such pipes is due to the following:

• Low durability of reinforced polypropylene pipes, especially with significant temperature differences;
• Ensuring a stronger connection of the reinforced pipe with reinforcement parts, for which it is necessary to remove part of the aluminum foil;
• For fiberglass pipes, where the aluminum reinforcement is always located in the middle of the pipe wall.

Trimmer for polypropylene pipes with reinforcement includes:

1. Two couplings sized to allow stripping of pipe ends of different diameters (typically 16 to 120 mm).
2. Replaceable steel knives.
3. Pair of rotary handles.
4. Aluminium case.
5. Nozzle for electric drill (shaver).

A shaver is required for external trimming of pipes. It consists of two parts - a guide, which is made of durable D16T duralumin, and a hard-alloy cutting part. When introduced into the pipe, the latter rests on the guide, after which the drill is turned on (you can also use a puncher) and a part of the reinforcing layer of the pipe is cut out. Since the shaver has a certain length, the trimming for different pipes is always done at the same length, which facilitates their subsequent connection.

The price of a trimmer-nozzle for polypropylene pipes depends on the diameter, and is 400 ... 2000 rubles. Trimmers manual type cheaper: from 250 to 800 rubles.

The pipe stripping procedure (in its classical sense) consists in removing part of the outer layer of polypropylene and aluminum foil from the edge of the pipe so that the pipe and fitting can be welded during sleeve thermal welding. Some "specialists" believe that since pipes reinforced in the middle do not require stripping of the outer layer of polypropylene, they do not need to be stripped from the end of the pipe. However, it is not.

Process pipe stripping, especially large diameters, is quite labor-intensive. Many of assembly organizations would happily avoid the need to remove the aluminum layer before welding. And when the tempting one appeared and easy way To achieve this, some installers, despite the recommendations of responsible manufacturing plants, and often without even knowing anything about them, began to mount systems without using a cleaning (facing) tool.

Fig.1.

Fig.2. Trimmer for pipes reinforced with foil in the middle. View from above.

As a short empirical experience in the installation and operation of polypropylene pipes reinforced with aluminum in the middle without end cleaning of the metal shows, there is nothing critical in the short term. Pipes without stripping are welded as standard, the system is pressure tested, water is let in, and everything seems to be fine.

Fig.3. Installation of reinforced polypropylene pipes. In front of you are two pipes. One of them (right) was cleaned before connecting to the fitting (the foil is melted, there will be no contact between aluminum and water), the other (left) was not cleaned

But, as the thousand-year experience of human civilization shows, free cheese is found only in mousetraps. main reason, according to which most manufacturers responsible to the consumer advise using special end stripping, this is a fleeting electrochemical corrosion aluminum foil leading to delamination of the combined pipe and its operational degradation.

Fig.4. Installation of reinforced polypropylene pipes. Uncut pipe. On the face of physical degradation and stratification. As a result - the presence of leaks and cracking over time

Polypropylene pipes with smooth inner surface , indeed, they do not overgrow and are not subject to corrosion, however, in the case of pipes reinforced in the middle and reinforced “from the inside”, they can not only overgrow (polypropylene will swell inward, partially blocking the internal section), but also partially rot due to aluminum corrosion.

After reading everything written above, an inexperienced user or installer may exclaim in their hearts: “How confusing everything is! I will do better system on metal-plastic ”(note the common name for a pipe with a PEX / AL / PEX layer structure). However, do not rush, everything is actually simple and clear. We take classic pipes with reinforcement closer to the outer edge of the pipe. Bearing in mind that almost any more or less large object has a perforator, we buy for relatively little money a special cleaning nozzle for a perforator and without special efforts, using the adjustable torque of the tool, remove the outer layer of polypropylene along with aluminum. For those who do not have a puncher, and have to clean up different sizes of pipes, we can advise a novelty cleaning tool - manual shaver(cleaning) for four main pipe sizes (20, 25, 32, 40 mm).

Fig.5. Installation of reinforced polypropylene pipes. Tools for stripping polypropylene pipes reinforced with aluminum. In the photo - a nozzle for a hammer drill, a universal stripping tool for four pipe sizes and a standard stripping tool for two sizes

The only pipes that for the most part have the properties reinforced pipes and at the same time do not require stripping, are the so-called pipes with fiberglass. Such pipes have a three-layer structure with a middle layer of a compound (mixture), which contains a premix of fiberglass and polypropylene. That is, during the welding process, this layer can also be welded from the end, and even more so it will not enter into chemical reactions and corrode. Since all three layers of these pipes contain polypropylene and are basically the same type, these pipes are produced by co-extrusion, i.e. The layers of the pipe are superimposed on each other at the same time. In this case, there is no need to pass any layer previously through water bath, and use tie layers of adhesive.

Rice. 6. Polypropylene pipes reinforced with fiberglass do not require stripping.

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Popularity in today's market plastic pipes hard to dispute. They are found in every second apartment or house. Homeowners with plastic pipes can be understood. This material is durable, reliable, but at the same time very mobile, has low weight, cost and easy to process.

Of the four plastic pipelines, they are especially popular. They are further processed for even greater efficiency.

However, there are some nuances regarding the interaction with polypropylene pipes. In particular, for plastic products of this type, it is necessary to buy several additional tools that carry out trimming. Without facing, certain classes of polypropylene pipes cannot be soldered to each other.

What is it and why is it required? Now let's find out more.

Article content

Material Features

Polypropylene, like any other building plastic, is a special polymer with a certain set of properties.

You can list them for a long time, we will highlight only the most basic ones:

• strength;
• ease;
• ease of maintenance;
• the ability to manipulate segments at your discretion;
• lack of reaction to corrosion;
• low price;

It is thanks to these points that they have gained such wild popularity in the market.

But plastic products also have disadvantages. Before you buy them, you need to familiarize yourself with the list. weaknesses specific material. In particular, perhaps the most a big problem plastic - its vulnerable reaction to temperature changes.

Plastic does not like too high temperatures. If you pour water with a temperature above 100 degrees into such a pipe, that is, boiling water, then plastic, as they say, will float. Become soft and pliable. In this state, it is easy to deform it, and here it is not far from breakdown.

Actually, there is nothing unusual in this behavior. Pretty much any plastic behaves the same way. But it floats not only in the case of extremely high temperatures.

Even just hot water affects polypropylene in a certain way. It is about the coefficient of expansion of the pipe. For plastic, this figure is quite high, for steel and other metals it is extremely low.

FROM low temperatures it's not all right either. If from hot water polypropylene softens, then at extremely low temperatures, especially when freezing inside the water, it bursts. And it crashes unexpectedly. In general, as you yourself understand, contact with low temperatures also takes an unpleasant turn.

It is for such purposes that the reinforcement of plastic products was invented.

Reinforced polypropylene

In building language, reinforcement is the process of inserting load-bearing structure reinforcing and supporting frame, which prevents the destruction of the working material, and also improves its resistance to bending and compression loads.

But don't get scared right away. Nobody in polypropylene pipes steel frames doesn't shove. In our case, the loads are quite low, and the goal of the manufacturers remains the same - to create a lightweight and durable material with a low price. Therefore, two materials are used as a reinforcement layer:

• fiberglass;
• aluminum foil.

Fiberglass is stronger, but much more expensive. It is indicated inside the polypropylene pipe with a strip of a specific color. Red color - durable fiberglass.

Green or blue are weaker samples with average values. Although it certainly depends on the manufacturer. Therefore, before buying a pipe of a particular sample, you should contact a consultant.

Aluminum foil reinforcement is much more common in our area. In fact, it will be quite problematic to buy glass-reinforced polypropylene in some stores, while foil-reinforced products are found everywhere.

A machine is used to form the reinforcement layer. The machine winds the foil around the tube blank, then puts it into the second blank.

The output is the same polypropylene pipe, but with a much more adequate response to temperature changes.

Why is a cleanup needed?

Reinforcement has its advantages, but there are also disadvantages. The disadvantages relate to the complexity of working with polypropylene.

The fact is that stripping for polypropylene pipes, if we are talking about reinforced samples - it is simply necessary.

Without it, it is impossible to engage in gluing pipes with each other or with fittings. Rather, you can try at any time, but the result will not please you. A layer of foil will constantly interfere. He will either not allow normal fastening at all, or he will grab very weakly.

Stripping is just what is needed in order for the edge of round or profile pipes you could first free from the layer of reinforcement, and then securely and quickly fasten it as you please.

Note that only pipes with foil reinforcement need cleaning. Glass fiber samples do not face such limitations. In fact, that's why they cost more.

Stripping tools

You cannot clean the pipe with your bare hands: you must first select and buy a stripping tool.

In addition, the tool for polypropylene pipes differs depending on what tasks are set for it.

So, in our time, the masters use:

• shaver;
• trimmer.

A shaver is a tool that strongly resembles a clutch with holes and overhead handles. Its task is to externally clean the pipe from the plastic layer, and then remove and reinforce.

After processing, the shaver leaves pure polypropylene without reinforcement, burrs and other necessities.

Inside the shaver is equipped with tool steel knives. Outside, its body is made of light metals. It works just like a pencil sharpener. Only the cut of the knives is smoother, and is designed for the solid structure of polypropylene. You also need to work with it in the same way as with a sharpener.

Planted, made a few turns (usually no more than 5) and you're done. They sell a shaver for up to $10 per unit.

Trimmer - a tool of a similar pattern. If the shaver is intended for external stripping of reinforcement, then the trimmer is used for internal stripping.

It already resembles a modified one. Only, unlike a tap, it does not cut threads, but cuts off polypropylene shavings along with reinforcement.

It makes sense to use a trimmer when pipes are supposed to be soldered through a machine with heating according to inside pipes. The cost of a manual trimmer is 5-8 dollars. There are also more expensive models.

There are also mechanized nozzles. They are mounted on a drill or machine. The details in question show amazing efficiency.

The machine cleans a single pipe in just a second, while the stripping quality is simply perfect. But not everyone has access to such equipment. When repairing or building at home, the machine will completely replace the manual shaver and trimmer.

Overview and interaction with polypropylene pipes (video)

Stripping and soldering

The workflow is elementary and easily done by hand. All that needs to be done is to strip the pipe, and then fasten it with another piece or by heating.

Stages of work:

1. We prepare tools and materials.
2. We clean it with a shaver or trimmer.
3. If necessary, remove excess or burrs.
4. We solder the cuts.

It is advisable not to overdo it with cleaning. Three to five turns good tool quite enough. If you strip more, then the layer of polypropylene at the point of coupling of pipes will become too thin, and this is already fraught with weakening of the entire structure.

Metal in household communications is gradually being replaced various materials from polymers. The properties of polypropylene are especially attractive to the consumer, allowing it to be used for all household communications.

Polypropylene is resistant to corrosion and deposits, does not change properties under the influence of aggressive chemicals. Water transported through systems made of this material does not lose its properties. The large throughput is also important, due to the completely smooth inner surface.

Types of reinforcement

Unreinforced polypropylene is characterized by low thermal conductivity and resistance to high temperature. Over time, it changes shape. This property is called fluidity, which requires the installation of fasteners every 50 cm of the pipeline.

Fluidity is especially pronounced when elevated temperature internal environment. The main purpose of reinforcement is to reduce this quality. After reinforcement, the polypropylene material becomes more rigid, sags less when laid in a horizontal position, which makes the system more stable.

Aluminum tape reduces the coefficient of linear expansion to a level that is comparable to this indicator metal products. In addition, aluminum contributes to a decrease in oxygen conductivity. More better quality when reinforced with fiberglass. This material makes installation easier than aluminum tape as there is no need for stripping prior to soldering. It is also important that products with fiberglass are cheaper than products with aluminum tape.

For reinforcement, solid or perforated aluminum foil can be used. It can be located near the outer shell or in the middle of the wall. The solid foil is bonded to the polypropylene with hot melt adhesive. The use of low-quality raw materials in the production entails delamination during operation.

A similar phenomenon is impossible if perforated aluminum is used for reinforcement. Holes in the foil make it possible to create a monolithic connection between plastic and aluminum without using glue.

When choosing polypropylene products, it should be borne in mind that some manufacturers, in order to reduce costs, use low-quality raw materials and make pipes have too thin walls. This entails delamination and instability to internal pressure. By outward signs distinguish quality product from poor quality is quite difficult. You need to purchase material with the thickest walls (that is, one with a heavier running meter).

Recently, polypropylene pipes reinforced with fiberglass have appeared on the market. Sometimes they are called fiberglass. If a product reinforced with aluminum, in fact, consists of five layers, then the use of fiberglass makes it possible to obtain a material with a monolithic structure, since the middle layer is the same polypropylene, but mixed with fiberglass. All three layers are not glued, but welded, which completely eliminates delamination.

However, fiberglass-reinforced products still have one drawback - their linear expansion is 6% greater than when using aluminum. Why do we need stripping for polypropylene pipes before soldering. Some reinforced products must be stripped before soldering to remove the outer layer of polypropylene and aluminum foil, which prevents a strong connection with the fitting.

Stripping reinforced polypropylene pipes is always required when aluminum is used for reinforcement, and regardless of where the foil is located. The only difference is the tool used. If aluminum is located in the middle of the wall, a trimmer is used. Fiberglass reinforced material does not require stripping, since it is all made of polypropylene.

Stripping tool

The cleaning tool for polypropylene pipes makes it possible to work with products with a diameter of 16 to 110 mm. For diameters up to 63 mm, double-sided couplings are produced, which allows you to clean the ends with two various diameters if the aluminum layer is located at outer surface. The knives of this tool are made of non-blunt steel.

If the foil is located in the middle of the wall, a polypropylene pipe trimmer is required, equipped with adjustable knives, which makes it possible to adjust the tool to any diameter. As well as the clutch, the trimmer has double-sided design(for two different diameters).

Facing polypropylene pipes is cutting the foil from the end to the welding depth. If this procedure is carried out incorrectly, aluminum will prevent a reliable connection between the elements of the system, that is, the weld will not be of sufficient quality. During the operation of the system, water will interact with aluminum, which can lead to leakage and rust formation in heating appliances.

Another way to solve the problem of "how to strip a polypropylene pipe" is a nozzle on a drill (shaver). This method is used for a large amount of work to strip the outer layer of polypropylene and remove the reinforcing aluminum layer, if it is located at the outer surface. The body of the shaver is made of aluminum, the knives are made of tool steel.

Thanks to the shaver, stripping for polypropylene pipes is automated, facilitating and speeding up installation with a large amount of work.