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Reinforcement of polypropylene pipes

Polypropylene pipes are products that have many advantages arising from manufacturing features. Among them:

1. Polypropylene pipelines are excellent for cold and hot water, but for hot there are restrictions - up to 95 degrees, for a short time this value can be exceeded. But this feature is rarely paid attention to, since the feed for apartment buildings hot water is limited to this figure. Therefore, when discussing the disadvantages of polypropylene, mentioning precisely this feature (to withstand temperatures only up to a certain value), you can safely purchase them - boiling water at 100 degrees through the pipes will still not flow.
2. The coefficient of thermal expansion is quite large. Polypropylene allows expansion at high temperatures due to its flexibility, although there are situations when pipe displacement is highly undesirable, especially when they are laid under a layer of plaster or screed.

To neutralize these features, the reinforcement of the polypropylene water pipe is made. For a reinforced water pipe, expansion and high temperatures are not terrible, it does not expand, does not deform when heated to high temperatures.

Attention: you cannot rely on reinforcement alone in all cases. At a flow temperature of more than 100 degrees (with constant heating), there is a possibility that the material will begin to soften at the junctions with the fittings, the water supply itself simply cannot withstand the pressure!

Reinforcement for polypropylene today is used differently:

1. Fiberglass mesh. This option is considered one of the best, the pipeline is five-layered: two layers of polypropylene and three layers of reinforcement. In this case, the middle layer is a kind of mixture of fiberglass and polymer.
2. Aluminum foil is the most commonly used reinforcement method, which is the use of an aluminum layer with a thickness of 1 to 5 mm. Such a layer can be outside, inside or in the middle between the layers of plastic. The foil is connected with glue, such a pipe can be solid or perforated.

Stripping of the reinforced part in this case necessary in order to remove the layer of reinforcement from the place where the welding of individual sections of the water supply will take place.

Why is it necessary to clean the reinforced part?

The polypropylene layer can be cleaned in several ways:

Scheme of stripping reinforced pipes before flashing for connection.

1. External cleaning. This method is used when the foil layer on the pipe is external. The reinforcing foil must be removed, since when welding, the layers of plastic and aluminum are connected extremely poorly, that is, if the metal layer is not removed, the fastening of individual pipes will be of very poor quality. Therefore, using a special tool, the outer layer of the pipe with foil is completely removed to the depth necessary for putting on the fitting and welding individual sections.
2. If the reinforcement layer is inside the pipe, then a method is used in which the foil inside the cavity is removed. Here to remove the foil if the pipe melts during welding only from the outside? The fact is that aluminum should not come into contact with water at the attachment points, otherwise electrochemical processes begin inside the water supply system, and this will lead to the destruction of the entire reinforcement, that is, to delamination of the pipe, a decrease in the strength of the connection, leaks and so on.

For fiberglass reinforcing polypropylene, stripping is not required, since the mesh in this case is located inside the pipe, that is, when melted, it does not come into contact with the fittings in any way, and is also not afraid of water. Therefore, polypropylene pipes with a fiberglass layer are often preferred, despite its higher cost. Fastening in this case is more reliable, additional work is not needed before this. Such pipes are welded without stripping.

Pipe stripping tools

A variety of tools are used for stripping, this is a trimmer, manual stripping, special nozzles for a drill that works in automatic mode. Hand tools have removable or non-removable handles that allow you to work with them with great comfort, and special nozzles are used with conventional drills without shock mode, they are inserted instead of a drill.

When working with a drill, you need to be more careful, since polypropylene is a very soft material, the stripping process must occur without damaging it.

To clean and connect pipes, you need to prepare the following tools:

• a simple pencil for marking the level;
• roulette;
• soldering iron for polypropylene pipelines;
• scissors for cutting;
• selected cleaning tool.

Cleaning the outer and inner layer: we eliminate all unnecessary

In order to strip the outer layer of reinforcement, you can use a simple clutch with knives inside. The coupling is put on the end of the product, rotated, the cut after that is smooth and very even, the operation itself takes only a few seconds.

The trimmer allows you to remove the middle layer, its blades are located on the inner end of the tool. The process is as follows: the trimmer is put on the end of the pipe, several revolutions are performed, after which soldering can begin.

Nozzles for a conventional drill make it possible to remove the inner and outer layer of pipe reinforcement. The nozzles are put on instead of a bit on a drill, carefully controlling the speed, a layer of foil is removed, after which you can start welding pipes. The nozzle should be selected in accordance with the types of reinforcement for the pipe.

Cleaning a reinforced polypropylene product is necessary in order to remove a thin layer of polypropylene itself and reinforcement to prepare pipelines for welding. In this case, the material is removed to the depth required to put on the fitting. You can perform stripping using a special tool, the work itself does not take much time, you can use not only manual, but also automatic tools that facilitate the preparation of the pipeline.

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, pairing pipes with each other is laborious, and requires special training ends. This work can be facilitated by using special tools - 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 a 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 notchers (slot cutters, although they are also capable of performing curved contours).

The pipe trimmer includes:

1. A shaft, at one end of which there is a seat for a drill chuck, and at the other end there is 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 required 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 mounting a 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 pipes of different diameters in the fixture.
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 assembly.
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 of a car (for example, VAZ - they are easier to get in 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, of course, are subject to additional processing - for fastening 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 stroke cylinders of the decommissioned hydraulic press will provide the necessary rigidity 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 the bearing capacity of fluoroplastic is much lower than that of 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 will not be difficult to make a 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. Manual type trimmers are cheaper: from 250 to 800 rubles.

6700 0 0

Stripping for pipes of two types: technology and tools

What types of pipes require stripping? What is it for? What tool is used for this? Finally, how to properly clean the pipes in each case? In this article I will try to answer these questions.

Types of pipes

In one way or another, they need to be cleaned:

• Black steel pipes. They are cleaned of rust and other contaminants for painting and before manual threading;

In the second case, rust is not simply removed from the ends of the pipe. An entry for a die or a die is formed on them - the outer chamfer is removed at an angle of about 15 degrees to the longitudinal axis.

• Polypropylene pipes reinforced with aluminum foil.

Why is it needed

Steel

Cleaning before painting is designed to ensure maximum adhesion of the paint to the substrate. Painting over rust (especially seam) ensures that the decorative and anti-corrosion coating peels off in the shortest possible time. An alternative to stripping is the use of rust converters - phosphating compounds that turn iron oxides into a strong and chemically resistant film, on which paintwork materials can be applied directly.

Agree that painting a professional pipe in this state without stripping is not the best idea.

The threading approach allows the die or die to cut the first threads with minimal clamping force. The larger the chamfer angle, the stronger you have to press the die against the end of the pipe. If there is no chamfer, the tool, even with the maximum clamping force, will not enter the pipe or will break the first thread of the thread over and over again.

Polypropylene

Why do we need stripping for reinforced polypropylene pipes?

I'll start from afar.

Polypropylene has two problems associated with its work in hot water and heating systems.

1. When heated, the tensile strength of the pipe decreases. If at +20 PN 20 pipes are able to withstand a hydraulic pressure of 20 kgf / cm2, then when heated to a maximum of 95 ° C, the allowable pressure decreases to 7 - 9 atmospheres. No wonder: polypropylene is a typical thermoplastic with all the ensuing consequences;
2. The polymer has a very high (even compared to other plastics) coefficient of linear expansion when heated. If you raise the temperature of the pipe by 50 degrees, each meter of it will lengthen by 6.5 millimeters.

Both problems are successfully solved reinforcement.

It can be done in two ways:

1. By mixing into the polymer melt fibers- chopped glass or basalt fiber. The middle reinforced layer of the pipe is fused with layers of pure polymer without reinforcement into a single whole during the extrusion process;
2. Bonded between two layers of polypropylene layer aluminum foil about 0.5 mm thick. The quality of an aluminum-reinforced pipe strongly depends on the technology of its manufacture and the one used.

The typical working pressure of reinforced pipes is 25 atmospheres (as indicated by the designation "PN 25" in the marking). When heated, it decreases to 10-12 kgf/cm2. The elongation during heating also noticeably decreases:

A steel pipe under similar conditions is extended by 0.5 - 0.55 mm.

For obvious reasons, pipes reinforced with foil are most in demand for hot water supply and heating. However, one unpleasant surprise awaits the happy buyer: aluminum forms galvanic couples with copper and steel, which are often present in heating and hot water circuits.

The small thickness of the foil causes it to collapse due to electrochemical corrosion upon contact with water in just 2-3 seasons. As a result of its destruction, the pipe at the end, inside the socket fitting, begins to delaminate with a catastrophic drop in strength accompanying this process. A relatively weak water hammer or noticeable heating ends the career of such a pipeline ahead of schedule.

The obvious solution to this problem — remove the aluminum reinforcing layer from the welding area. Cleaning of polypropylene pipes is the preparation of the end of the pipe for soldering with a fitting, which boils down to cutting the foil from the surface of the pipe (with external reinforcement) or between two layers of polypropylene (with internal reinforcement).

Instruments

Steel

Steel pipes are prepared for painting using:

• Manual metal brush;

• Nozzles similar in functionality to a drill or grinder.

Cleanup profile pipe may be somewhat automated. The simplest machine for stripping pipes from rust is a cartridge with a brush clamped into it, planted on an electric motor shaft, and a movable thrust roller with a locking mechanism that allows processing pipes of arbitrary section. The pipe is slowly pulled through the machine by hand with a 90 or 180 degree turn between successive brush passes.

In the photo - the simplest machine for stripping rust from a professional pipe.

How can you prepare the end of the pipe for threading?

• file for metal;

• Bulgarian with a cutting wheel for steel;

The pipe will have to be turned with a circle plane. Avoid pushing too hard: broken circle fragments often cause serious injury.

• Finally, in the absence of a more suitable tool, a pipe with a diameter of 15 - 25 mm can simply be slightly crushed in a circle with a gas wrench or blows of a heavy hammer.

Polypropylene

A stripping tool for polypropylene pipes is most often called stripping. In stores with a more qualified merchandiser, you can find more accurate names:

• Shaver is a stripping for external reinforcement;
• The trimmer allows you to cut a foil layer glued into the middle of the wall between polymer layers of approximately the same thickness.

And this tool can be manual (with a notch on the outer surface or comfortable handles), made for installation in a drill or puncher chuck. Often it is equipped with a pair of knives, which allows you to remove the outer chamfer from the end of the pipe.

The nozzle is a shaver chambered for a perforator.

The price of the tool is determined by the size, functions and manufacturer. Here, for example, is the cost of a line of trimmers from Valtec, designed for installation in a punch chuck.

Technology

I sincerely hope that the instructions for stripping pipes from rust and chamfering are not required by the dear reader: this is a simple mechanical work, devoid of any subtleties.

Do-it-yourself stripping for polypropylene pipes is not much more difficult:

1. After examining the cut of the pipe, select the appropriate tool (shaver or trimmer);
2. Insert the pipe into its socket;
3. Make several full turns.

Trimmer knives remove reinforcement to a depth of only about 2 mm. Cleaning the pipe takes 5 to 15 seconds.

Conclusion

We will consider our acquaintance with simple stripping technologies to have taken place. Additional materials, as always, can be explored by watching the video in this article. I look forward to your additions and comments. Good luck, comrades!

July 22, 2016

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Pipe stripping is done in order to get rid of the polymer layer and protective coating, which is necessary for subsequent welding work. At the same time, it is taken into account that the material is cut off to the thickness that is needed for fitting the fitting.

To do this, you need a special device. Such devices are small, they are perfect for home use in the bathroom or toilet room. There are also large ones - for processing pipelines of a significant scale, which are usually used in the construction of multi-storey buildings.

Many would like to know how to clean polypropylene pipe and why is a thorough cleaning of the ends of polypropylene pipes required, despite the fact that they, it would seem, are already quite smooth.

In order to avoid damage and undesirable consequences, the polypropylene pipe is protected.

Note! Do not rely only on the reinforcement of the coating. Pipe fixing points may contain irregularities and temperatures close to 100 °C can lead to softening of the pipe joint, leading to leakage. That is why it is required to clean the ends at the joints of the pipes.

How to properly remove the reinforced layer

Polypropylene pipes can be cleaned by the following methods. If the reinforced layer is located on the inside, the foil should be removed from the inside cavity.

Note! Aluminum should not come into contact with water, which will easily enter into an electrochemical reaction with it, which will lead to the destruction of the entire reinforced layer.

If you are dealing with fiberglass that protects the polypropylene layer, stripping is not required at all, since the mesh part of the fiberglass is located on the inside of the pipeline, it will not come into contact with the fittings during melting, and it is not afraid of water. That is why it is often preferable to choose polypropylene in combination with fiberglass. Preparation does not take much time, pipe installation and fastening of joints are easy, welding of polypropylene pipes is carried out without stripping.

Stripping the outer layer. In this case, the aluminum tread layer is on the outside. This foil should be removed, due to the fact that when cooking, the joints of aluminum and plastic are extremely unreliable. With the help of special equipment, the reinforcement is removed to the depth required for fitting the fitting and connecting other parts.

In such work, a technical trimmer, an electric drill are most often used; manual cleaning is possible without a special tool. Tools for manual use have a convenient removable handle for greater comfort. When working with a drill, special nozzles are used, which are mounted instead of a drill.

The cleaning of the outer reinforced part begins with the fact that a special coupling is mounted on the end part of the material. Then the clutch should be turned 1-2 turns, after which you will get a perfectly even cut at the exit. The whole process is extremely simple and will not take more than two minutes.

The trimmer cuts off the intermediate layer, its tips are mounted from the inside. The work is as follows: the trimmer is mounted on the tip of the pipe, a couple of turns are made, after which you can start welding.

Working with an electric drill

Special nozzles for an electric drill make it possible to remove the inner and outer layers at once. When working with a drill, attention should be paid to the number of revolutions of the device. The nozzle should be selected individually depending on the type of reinforcement.

Do-it-yourself cleaning of polypropylene pipes is possible in cases where you need to quickly remove a layer of polymer and a reinforced part, but the necessary device is not at hand. In this case, the layer is cut off with an ordinary technical knife, to the same depth that is required to mount the fitting. You can perform the work with the use of special tools and without them. The process itself is very simple, does not require special skills and will not take more than five minutes.

Video

This video shows the process of removing the reinforced layer of pipes from polypropylene without special tools:

Market building materials offers big choice pipes made of polymeric materials.

Advances in organic synthesis have made it possible to create materials that show excellent performance characteristics.

Polypropylene products are popular - every second apartment or private house have plumbing or heating from such pipes.

Technical description

Modern technologies have made it possible to create a durable, lightweight material, which is not subject to corrosion, has good strength characteristics, does not react with aggressive media.

small price, low weight, ease of installation determine the widespread use of polypropylene pipes (what is it).

The industry produces several types of products, some of which contain a reinforcing layer outside or inside the pipe.

Quality soldering such models is possible only in the case of stripping the ends of aluminum foil.

We use two types of shaver:

• manual,
• automatic.

The first ones are used when performing one-time operations, the second one is able to clean pipes in large volumes, which is typical for large construction companies ().

The need for reinforcement

The plumbing or heating system made of polypropylene, in addition to the advantages, has several significant disadvantages.

Despite the ability to transfer water with a temperature of 90-95 degrees and withstand short-term heating up to 100 degrees, the polymer has a high coefficient of thermal expansion (about the installation technology metal-plastic pipes read the article).

Flexible Structure will allow the product to restore its shape when the temperature drops.

But such a situation can become critical when the pipeline is hidden in the walls or under the floor.

Adding a layer of fiberglass or aluminum foil to the composition of the product will reduce thermal expansion and avoid deformation when heated.

Reinforcement helps to linear sections pipeline, but there is no foil in the compounds. This leads to softening of the polymer at temperatures above 100 degrees.

In such places, a breakthrough of communications is possible, therefore the use of reinforced products is not recommended for industrial pipelines.

Used to reinforce pipes.:

• fiberglass.
  Structurally, the pipe consists of two layers of polypropylene and a middle layer of a combination of fiberglass and polymer.
  Such products do not need to clean the ends before welding;
• aluminum foil.
  Popular type of reinforcement.
  Manufacturers produce pipes with different foil thicknesses.
  More common are polypropylene pipes reinforced with fiberglass () with a layer thickness of 0.1-0.5 millimeters.
  The metal layer can be located inside the product or cover the pipe from the outside.

Why do you need to clean the ends

In the process of stripping the reinforced product, the metal layer is removed at the place of the future connection with the coupling or fitting.

The need for external stripping occurs when using reinforced pipes with an outer layer of foil. Without removing the reinforcement, it is impossible to solder the pipes.

To remove metal from the surface, a special tool is used (which is needed for the installation of pipes made of cross-linked polyethylene, it is written), which cleans the product to the depth necessary for welding.

Drill bits made for one pipe diameter.

To work with such a tool, it is necessary to prepare the necessary nozzles in advance.

Using a drill will increase the stripping speed, the number of processed pipes and labor productivity.

The nozzle is able to work both with external reinforcement and with internal.

How to choose

Product is selected, according to the type of pipes, and is clamped into the chuck. The disadvantage lies in the high speed of rotation - it is necessary, constantly, to control the process. Otherwise, the pipe may be damaged.

If you want to know how to perfectly clean the end of a pipe before welding, watch the video.