AT last years metal pipes are increasingly being replaced by more convenient plastic (propylene) products. Welding technology polypropylene pipes allows you to get high-quality connections and extend operational terms sewer networks up to 50 years.

At the same time, the pipes and connecting elements that make up them practically do not collapse over time, weigh little and allow you to assemble pipelines on your own (without the involvement of specialists).

In order to weld poly propylene pipes with their own hands, the performer will need the ability to handle special tool, as well as the presence of certain skills in working with plastic materials.

For joining polypropylene pipes, a special method has been developed, called polyfusion thermal welding. The essence of this welding method is to heat the sections of polypropylene pipes to a fixed temperature and then quickly connect them.

To preheat the joints, a special device is used, colloquially called a "soldering iron". An apparatus for welding polypropylene products (soldering iron) is often equipped with two heating elements, which allow you to equip a couple of joints at once.

For each of the workplaces, a separate control unit with a switch is provided, and their power is sufficient to melt pipes and fittings of a given diameter.

It is not recommended to work on two heating elements at once, since you can overheat the plastic, as well as greatly overload the network. The second element is usually used as a backup, switched on in case of a malfunction of the first.

In cases where the soldering iron has two heating circuits, their simultaneous inclusion is allowed only immediately before welding the polypropylene pipe. This technique allows you to quickly heat up the welding element to the required temperature, after which one of the two circuits is simply turned off.

Work order

Polypropylene pipe welding equipment does not require special skills and allows you to quickly master the basic fusion techniques.

Since the molten polypropylene retains its plasticity for some time, during these seconds it is possible to dock the elements and fix the resulting connection by means of an external force.

Experienced craftsmen (specialists in polyfusion welding) at the same time manage to eliminate barely noticeable distortions.

As the material solidifies, it loses its plasticity, after which the force fixing their position is removed from the jointed workpieces.

The optimum temperature for welding polypropylene pipes is 260 degrees, the excess of which can lead to a loss of shape of the products themselves. In addition, their excessive heating is often the cause of the formation of sagging and narrowing inside the pipe.

To eliminate this undesirable phenomenon, it is necessary to constantly control the heating time, which is regulated special instruction and is selected according to the pivot table.

Polypropylene pipe diameter	Welding depth	Heating time	welding time	Cooling time
16	12-14 mm	5 s	6 s	2 minutes
20	14-17 mm	6 s	6 s	2 minutes
25	15-19 mm	7 s	10 s	2 minutes
32	16-22 mm	8 s	10 s	4 min
40	18-24mm	12 s	20 s	4 min
50	20-27 mm	18 s	20 s	4 min
63	24-30 mm	24 s	30 s	6 min
75	26-32 mm	30 s	30 s	6 min

The opposite effect associated with insufficient heating of the place of welding of polypropylene pipes leads to the production of a poor-quality joint, in the zone of which a leak may occur over time.

For more confidence in good result before starting welding of polypropylene pipes, you should practice using trimmings and used connectors (fittings) for this.

The instructions and tables for welding polypropylene pipes also indicate the exact values ​​\u200b\u200bof their cooling time after joining. According to the specified documents, this should be given the same amount of time as it takes to heat the junction.

Beginning users are usually in a hurry and remove the holding load ahead of time, as a result of which the pipelines at the junction are subjected to unwanted deformation.

Apparatus for sheet polypropylene

The technology of welding sheet polypropylene blanks is to fuse them along a carefully prepared cut line. The following methods can be used to form a quality compound:

• automatic welding;
• manual welding with a soldering device;
• a similar method, but using a special technical hair dryer.

Polypropylene Sheet Welding Machine

Automatic joining of polypropylene sheets is one of the most effective and high-quality methods, which are implemented using polyfusion welding.

For this, a special type of equipment is used, in the form of work machines or sliding tables, on which workpieces are placed during the welding process and fixed by means of a clamping mechanism.

Before starting welding procedures, the operator sets the parameters of the future seam (their thickness and length), and then presses the "Start" button.

Using the same fixing mechanism, the edges of the polypropylene sheets are pressed against the heating element and then heated for a certain period of time.

When heated to a predetermined temperature a heating element withdrawn from working area, a sliding elements continue to compress the parts exactly along the cut line. The duration of compression and the force developed in this case are strictly normalized and set by the operator before the start of the fusion procedure.

With this method, polypropylene sheet blanks can be joined regardless of their shape, length and thickness. Width of the working part extendable table for some models of machines it can reach 3-4 meters.

The above parameters satisfy the indicators various materials from propylene, which is very advantageous for the processing of large quantities of these products.

Hand soldering irons and hair dryers

Manual welding of a polypropylene sheet, pipe or other part can be carried out by fusion using a soldering iron, or using a technical hair dryer (extruder).

To facilitate the fusion process, a special filler rod is used, made from the same polypropylene.

Before welding the workpieces by this method, the surfaces to be joined are cleaned with fine sandpaper, which eliminates all existing irregularities and ensures perfect mating.

The rod for welding polypropylene parts first enters the extruder, where it is heated to the required temperature. And only after that they go directly to welding the sheet blanks themselves by compressing them.

Upon completion of this procedure, the joint is left for about five minutes so that it can cool completely.

Since working with an extruder involves manual control, when using it, it is not always possible to ensure the uniformity of compressive forces, which affects the quality of the seam.

Note that the seam obtained by manual fusion is inferior in quality to the joint formed by automatic welding. Its strength index (in comparison with monolithic polypropylene product) does not exceed 0.8.

cold welding

The technology called "cold welding" involves the use of a special plastic composition, the time of readiness for use (at room temperature) does not exceed five minutes.

This composition has characteristics approaching those of metallic materials, and is intended for the prompt restoration of pipe depressurization points.

For polypropylene pipes, cold welding is the best fit, as it has good adhesion even to heavily contaminated plastic surfaces.

For the same reason, it is often used in the repair of radiator heating systems with polyethylene supply channels.

The order of preparation for cold welding polypropylene pipes is not complicated at all. It involves making special composition, which is kneaded in a pre-calculated proportion and immediately distributed over the joint.

After application repair composition"freezes" for about 20 minutes; at the same time, it is allowed to start the operation of the restored pipe no earlier than after 2 hours.

Under no circumstances should this chemically active composition come into contact with the face and eyes, and when working with it, the use of rubber gloves is mandatory.

For welding polypropylene sheet products, any of the previously described methods can be used. Their choice is determined by the preferences and capabilities of the performer.

Now no one questions the reliability of polypropylene pipes. At correct operation they can last up to 50 years. All thanks to the uniqueness of the material, which does not rot and does not corrode.

But in order for everything to go according to plan, and your pipeline to serve you for many years, it is necessary to carry out the correct welding of polypropylene pipes. To do this, you will need to follow the instructions.

Attention ! Polypropylene is a type of plastic.

Due to its unique properties and long term exploitation was practically forced out of the market hardware. As a result, everything more people want to know how to properly weld such pipes.

It’s worth starting with the fact that there is a long-verified instruction for assembling polypropylene pipes. It will allow you not only to connect products of the same diameter, but also to make complex wiring. For this, special adapters are used.

Installation instructions for polypropylene pipes also include work with bypasses and installation different kind fittings. As a result, you can assemble a system of any configuration.

Unfortunately, it hasn't been without drawbacks. Despite all its advantages, after welding and installation, polypropylene pipes cannot be separated. Moreover, even if you separate them, reusing the products will not work. That is why you must do everything according to the instructions. In this case, the created design will not require further development.

Welding polypropylene pipes

Necessary equipment

Preparation for the process of welding polypropylene pipes begins with the selection of a suitable tool. In order to do everything exactly according to the instructions, you will need:

• apparatus for socket welding;
• special nozzles for different diameter pipes;
• wire cutters,
• beveler,
• shaver.

Each of these tools can be found in hardware store. But there is one caveat here, so that the welding of polypropylene pipes takes place exactly according to the instructions, it is necessary to buy not the cheapest equipment. For example, a high-quality welding machine allows you to work much longer without damaging the Teflon layer of the nozzles.

Advice ! If you do not want to spend money on buying a machine for welding polypropylene pipes according to the instructions, rent it.

In most cases, nozzles come with the device. But cheap analogues may not have them. So if you see too low price, be sure to ask about the scope of delivery.

Welding instruction

The welding machine is not something super complicated. It is quite convenient to use it. Especially if it's well made. The instruction for welding polypropylene pipes itself consists of the following steps:

1. Take measurements and cut the polypropylene pipes to the length you need.
2. Training. In order for the welding process to proceed exactly according to the instructions, it is necessary to immediately prepare all the elements. This will avoid confusion. Fittings must be laid out in order of priority for installation.
3. Preheat the welding machine. Set the temperature control to 260 degrees Celsius. As soon as the device reaches the desired temperature, the signal light will turn off.
4. Heat up the surface of the polypropylene pipes with a welding machine and join them together. Do not make turns while doing this. This may lead to depressurization.

When connecting polypropylene pipes according to the instructions, you must strictly maintain the cut angle. Otherwise, you can forget about the sealed seam. At the very end, the connection is cleared.

Attention ! Stripping is done only after the seam has cooled.

The nuances of welding technology

In order for the welding of propylene pipes to pass according to the technology, you need to know some important technical details this procedure. You need to start with how to properly heat the parts.

Heating is done with outside along the edge of the pipe. In turn, the clutch warms up from the inside. In this case, the depth of heating should not be too large. Only after that you can connect the parts according to the instructions.

The technology for welding polypropylene pipes according to the instructions is actually quite simple. In the place where the two parts are connected, the previously heated material is welded.

To make cuts exactly according to the instructions, you must not forget about the chamfer. As a standard, it is best to take the German norm DVS-2207-1. According to this standard, the slope is 15 degrees, and the recess is in the region of 2-3 mm.

If we take the domestic standard, then the chamfer according to the instructions must be done at 45 degrees. In this case, the recess will be a third of the thickness of the pipe. In fact, both options are suitable for welding polypropylene pipes. If we talk about their effectiveness. There is no reliable data on this issue. But most builders use the German version.

Attention ! Before chamfering, the polypropylene pipe and the inside of the chamfer must be cleaned according to the instructions. It also does not interfere with degreasing.

The welding machine must be installed on a special stand. The welding process itself is as follows: on the one hand, a fitting is mounted, and on the other, a pipe.

After the parts reach the desired condition, they must be quickly removed in order to be immediately connected. The shorter the cooling period, the more welding of polypropylene pipes will meet the instructions for quality standards.

Attention ! The holding time of the parts depends on the diameter and thickness of the polypropylene pipe.

Parts must not be allowed to overheat. If this happens, the fitting and pipe will most likely be deformed. All due to the loss of strength, which is caused by too high a temperature. Naturally, after such a connection will be impossible.

Insufficient heating when welding polypropylene pipes according to the instructions is strictly prohibited. The fact is that a connection made in this way will not have the necessary reliability. Because of this, the risk of loss of tightness of the entire structure is greatly increased. In this case, there can be no talk of a long service life.

To insert the pipe into the sleeve, you will need to apply a certain force. The same goes for the fitting. The fact is that the nozzles are made in the form of cones. In this case, their slope is five degrees. At the same time, the diameter working surface, corresponds to the product only in the middle.

When you insert the product into the sleeve, you need to bring it to the stop. The difficulty lies in the fact that it is impossible to push further under any circumstances. This may damage the structure.

With strong pressure, the conductivity of the product deteriorates. This is due to the fact that a thickening forms at the end. But since it is inside, it is not easy to notice it from the outside. Therefore, maximum caution must be exercised.

In order not to make a mistake and do everything according to the instructions, measure the depth of the sleeve. After that, take a ruler and make an appropriate mark on the tubular product. Such a precaution will insure you against unpleasant surprises.

Attention ! When you connect the product together with the coupling, you will have a few seconds left to correct their position.

Degreasing the welding area

To achieve a good and high-quality connection, you must first degrease the welding area. Take a cotton swab and pour some alcohol on it. After that, process the inside of the fitting. Do the same with the end of the pipe.

Don't forget to remove abrasive particles. Even dust can adversely affect the quality of the connection by welding polypropylene structures. That is why so much attention is paid to this issue in the instructions.

Attention ! Dust and abrasive damage the Teflon coating of the welding machine.

Alcohol needs to be treated not only with parts, but also with nozzles. This precaution will avoid plastic sticking. This also reduces the risk of damage to the Teflon coating. This happens quite often when the remnants of dried polypropylene are mechanically removed from the work surface.

How is the installation carried out

Installation is done when the elements with fittings are mounted. Turns must also be set. The latter are best welded separately so as not to violate the instructions.

Do not forget that according to the general building instructions, you must take care of the transitions between the walls. You also need to make a connection to the inputs. Then welding can be carried out on weight.

Pipe products are attached to the walls by means of clamps. They provide reliable fastening and can last for decades. The polypropylene construction itself is simply threaded into them.

Attention ! If you have private house, then plastic structures not connected directly to the boiler. This will require a special fitting.

The main part of the fitting, which connects the polypropylene structure with the boiler, is a metal part, the length of which is about half a meter. It is connected directly to the heater.

The advantage of polypropylene structures is that they can be easily laid inside walls, and this in no way violates the operating instructions for a residential building. However, before using the pipeline, it is necessary to carry out a leak test.

Results

As you can see, the instruction for welding polypropylene pipes is not anything particularly complicated. It is enough to follow the recommendations, withstand correct temperature and don't forget about pre-treatment and degreasing parts.

AT modern systems water supply and heating, cast iron has not been used for a long time. He was replaced by light, easy to install and not corroded plastic. Today we will talk about welding polypropylene pipes with our own hands for beginners - the main stages of this process and its intricacies.

Required Tools

For work we need:

Fitting;

Polypropylene pipes themselves;

Special apparatus for welding such pipes;

Welding machine

A hacksaw for cutting them, a special cutter is often sold complete with a welding machine, with large volumes works, you can use a ring cutter or special scissors;

Degreaser (ethyl or isobutyl alcohol); acetone in this case is forbidden to use, as it is able to soften the plastic;

Beveler: Its inside resembles a pencil sharpener, however, since the bevel must be cut evenly, the knives are located at a different angle; you can replace the beveler with an ordinary file and a knife;

Chamfer for plastic pipes

Shaver: a tool for removing the reinforced layer (if our pipes have a layer of reinforcement).

Shaver

Advice. Pipes that fit close to the heating boiler (at a distance of less than half a meter) should be made only of metal. They are connected to polypropylene using adapters from a welded joint to a threaded one.

Main stages of work

To fill your hand, for starters, you can try to practice and connect a pair of pipes. For this:

1. We take a pipe of the right size.

2. We clean its edges from burrs formed during cutting with a file or beveler.

3. We mark with a pencil at the end of the pipe (see photo) which section we need to melt, that is, we outline the place where the fitting will be put on.

We outline the place of soldering with a pencil

4. We process the pipe and fitting with a degreasing agent.

5. Firmly fix to the table welding machine.

6. Its kit includes nozzles of different diameters. We take the required nozzles (one for the fitting and one for the pipe) and fasten them on both sides of the device.

7. Set the temperature to 260°.

8. As soon as the lights go out (this means that the device has warmed up enough), you can start working. The average heating time is 2-3 minutes.

9. We put on hot nozzles (there are two of them) a fitting and a pipe to a pencil mark. Too much pressure on the parts to be welded or rotate them should not be.

Butt welding machine. Fitting and pipe are put on hot nozzles

10. We count the prescribed amount of time. The heating time is always indicated in the instructions. For example, for a 25 mm pipe it is exactly 7 seconds).

The heating time of the device depends on the diameter of the pipe

11. Quickly and accurately remove the heated parts, slightly holding the welding machine.

12. We connect them with each other. Excessive pressure on them or rotation is also unacceptable.

13. We are waiting for a few seconds.

14. If we did everything right, we get a perfectly even, homogeneous connection.

Beginners, having first become acquainted with the welding machine, should listen to the following recommendations:

The reinforced layer on the segment of the connection must be removed, otherwise the connection will be inhomogeneous and fragile;

When buying a device, it is not necessary to spend extra money and purchase a model with a thermostat, because we need only one temperature regime at 260°C; using other modes may result in a poor connection;

Water must flow freely through the pipes; so that an obstacle in the form of frozen plastic does not form at the place of soldering, do not put too much pressure on the melted parts when connecting; however, low pressure is also unacceptable - the length of the connection for reliable fastening will not be enough; this can lead to the formation of turbulence and pressure drop in the system;

The basic rule of such soldering is: the fitting is put on the nozzle first, and only then the pipe; the countdown starts when both parts are on the machine;

Polypropylene seizes in 4-8 seconds, but you should not immediately release it - in order for it to completely freeze, you need to wait 20-30 seconds;

Parts during cooling must be motionless, the slightest shift can break the tightness of the connection; therefore, before soldering, it is better to prepare special clamps for fixing them; you can make them from any bar of wood or strong wire;

Cooling the resulting node with water or a jet of cold air is prohibited - the connection will be fragile;

Do not heat up the pipe and fitting more than the allotted time - polypropylene will be deformed; with less time for heating, the connection of parts will be difficult;

With proper welding, part of the plastic should form a slight influx on the sleeve;

You can check the quality of your work by cutting the connected section in half; you should see at the junction an even monolithic connection without deformations and voids.

Which pipes to choose?

Polypropylene pipes are divided into three main types:

Reinforced with fiberglass: since polypropylene is able to expand when heated, reinforcement is used to neutralize thermal expansion (changing pipe dimensions when heated); such products are used for laying pipes of the heating system when it is heated to 90 ° C: with a standard wall thickness of 3.5 mm, their inner diameter is 25 mm;

Reinforced with foil: the principle of operation is similar to the previous one; withstand greater heating up to 95 ° C;

Without reinforcement: they have the same diameter, but the walls are slightly thinner - 2.8 mm.

For cold water supply, you can use any type of pipes, however, it is most rational to mount ordinary single-layer pipes without reinforcement in the system. After all, their cost is lower. In heating systems heated above 70 ° C, it is better to use products reinforced with foil. It is better to take fiberglass only in cases where the heating system does not heat up above the specified limit.

Important! Pipes without reinforcement do not tolerate impact well high blood pressure and elevated temperatures, therefore, they are not intended for the installation of heating systems.

Video: Do-it-yourself welding of polypropylene pipes

Part 1

Part 2

Part 3

This piping technology for various purposes, as welding of polypropylene pipes, has become a real find for many amateur craftsmen.

Polypropylene pipes are used in plumbing, heating and sewer communications.

Having chosen this method, the devices of water supply, heating and sewer communications ceased to be dependent on the services of welders, who were quite expensive.

Advantages and disadvantages of PP

Polypropylene pipes have a number of advantages, including:

• long service life;
• no corrosion;
• small mass;
• ease of installation, which can be handled by a person who does not have the qualifications of an electric gas welder.

The disadvantages of PP pipes include:

• lower, in comparison with steel pipelines, strength;
• high coefficient of thermal expansion;
• destruction of the material under the influence of ultraviolet radiation.

For pipelines with cold water the issue of thermal expansion is not as relevant as for hot water pipes and heating systems However, with the start of production of PP products reinforced with foil or fiberglass, the problem of sagging of heated conduits can be considered closed. As for strength, it is better to place plastic pipes under the cladding. In the same way, they should be protected from sunlight.

If you decide, after weighing all the advantages and disadvantages of polypropylene pipes, to build a pipeline out of them with your own hands, then recommendations on how plastic pipes should be welded will surely come in handy.

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What pipes to use

It should immediately be said about the most popular in the device pipeline systems of pipes made of polypropylene. Among them:

• pipes with a cross section of 32 mm (they are used in risers and supply pipelines);
• products with a diameter of 25 mm (used for the installation of risers, floor wiring, installation of heating systems)
• pipes with a diameter of 20 mm (connection of water supply and heating system).

It must be remembered that for transportation hot water reinforced pipes should be used, whose coefficient of thermal expansion is 0.03, and for cold water you can use cheaper products without a reinforcing layer (their expansion coefficient is 0.15).

Nevertheless, a change in the linear dimensions of the pipeline, even reinforced aluminum foil or fiberglass in a section 5 m long can be 15 mm (what can we say about non-reinforced tubes, the length of which, when heated to 90 ° C, increases by 1.5 cm per linear meter).

This factor should be taken into account when designing a heating or plumbing system. To avoid stresses in the pipeline, on its straight sections with a length of more than 5 m, it is necessary to install not rigid, but only fasteners supporting the pipe. In addition, compensators should be mounted on such runs. They can be manufactured U-shaped or in a loop.

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Types of welding of PP pipes

Scheme of welding PP-pipes "butt".

Additional turns of the line will require the use of fittings, and to connect them and pipes in single system welding of plastic pipes will help. There are 2 types.

1. Fitting welding.

As for the latter, it is used when assembling pipelines with a diameter of 50 mm or more and a pipe wall thickness of 4 mm or more. This method will be discussed later. It should be noted that at home, the installation of such a pipeline is rarely carried out, since it requires rather expensive specialized equipment. This technology is mainly applied to construction main water pipelines, including sewage.

Fitting welding has become more widespread, which is easy to do with your own hands by buying or borrowing for a while a device for soldering polypropylene pipes.

This welding machine (in other words, an iron or a soldering iron) does an excellent job of connecting the pipelines most in demand in construction individual systems water supply and heating diameters.

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Fitting welding technology

Fittings are required for welding polypropylene pipes.

PP pipe welding technology is based on physical properties polypropylene that melts when heated to 175°C, but is able to regain its strength when cooled, which occurs in a matter of minutes.

When welded, they heat up and melt and end part tubes and fittings. When docked in a hot state, they are soldered together and, when cooled, turn into an almost monolithic connection.

Welding of the pipeline is carried out with a special soldering iron, but you still need to use:

• marking tool;
• hacksaw for metal;
• construction knife.

However, with the help of a hacksaw and a knife, it is difficult, although possible, to achieve quality processing end edges of the tubes, so it is better to use a pipe cutter for cutting, as well as a shaver, which cleans the internal cavities of the tubes with reinforcement before welding.

Since the tubes are driven into fittings during welding, when calculating the length of the pipeline system, it should be taken into account that each tube will be buried in them by 14-22 mm (depending on the diameter of the pipes and fittings) from each end. When calculating the total length of the pipeline, you need to add the result of the calculation (for example, 15 mm x 2K, where K is the number of welded joints).

The "iron" is equipped with special nozzles, in which pipes and fittings of corresponding diameters are simultaneously heated. The heating temperature is 260°C. As soon as the polypropylene becomes sufficiently plastic, the elements of the pipeline are connected and held for some time with some effort. During fixation assembled parts loads that deviate away from the axis of the assembly are not allowed.

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Errors when welding conduits

In addition to various distortions that will lead to insufficient tightness of the seams, House master when assembling the conduit, it can make a few more mistakes.

1. Dirty or wet pipes are mounted: dirt will cause lack of fusion, and water evaporating when heated will deform the connection or form “shells” in it. To avoid such troubles, the tubes should additionally be cleaned immediately before welding.
2. The cavity of the reinforced PP tube to be heated is poorly cleaned of aluminum foil: it is necessary to check the quality of the cleaning of the walls.
3. Polypropylene remains on the nozzles of the soldering iron after welding the previous section - in this case, the remaining plastic must be removed, but you can only use it to remove wooden fixtures or a cloth so as not to damage the Teflon layer. Cleaning of nozzles should be carried out on a slightly warm instrument.
4. Using low-quality material for welding - you should buy PP pipes only from bona fide sellers. Unreasonably cheap products should be suspicious.
5. The reason for poor-quality welding is the use of pipes made by different companies. They may have different chemical composition, therefore, the time of their heating and cooling, as well as the degree of softening and the ability to diffuse, may vary. For each circuit, it is better to purchase products from the same manufacturer. It is advisable to purchase all elements of the conduit in one batch.
6. Poor-quality installation of the pipeline - it has already been written about distortions, but the tightness of the joints is detrimental to:

• insufficient penetration of the workpiece into the fitting;
• weak heating of the elements (there will be no reliable soldering) or delay in connecting the pipes, which will lead to the plastic solidifying even before they are assembled;
• overheating, due to which slush can form, impairing the permeability of the collector;

In order for the welding of plastic pipes to be of high quality, you should use the data in the following table.

It can be seen from it that it is necessary to connect the heated PP tubes as quickly as possible, and they should be pressed against each other for the time specified in the "Welding Time" section. In addition, home craftsmen who decide to assemble the pipeline on their own can be advised to weld the line even before it is assembled on site, where it will be inconvenient to do so. Therefore, a detailed diagram is needed indicating the exact dimensions of all sections of the pipeline and its configuration.

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How to weld polypropylene pipes correctly

Polypropylene pipes are gaining more and more popularity in domestic engineering networks, in chemical industry and agriculture due to the combination of their strength, reliability, durability and low cost.

Another advantage over metal pipes is a fast and durable welding of polypropylene pipes into piping systems using fittings and valves.

Some thematic terms

The connection of pipes is called socket welding or socket welding, since welding is not end-to-end, but with the help of a fitting or coupling. The welding machine is called a "soldering iron" or "iron" although this is not entirely true. Two parts of the nozzle are installed on the sting of the apparatus: a mandrel - a part for a fitting, a sleeve - for a pipe. A shoulder or a roller of melted plastic, an extruded pipe or fitting when attached to the apparatus, is called differently, but correctly - burr. Polypropylene pipes can be of two main types: conventional and reinforced. Grades PN10, PN16, PN20 are made entirely of polymer and are uniform in structure. Reinforced pipes, grade PN25, reinforced with aluminum foil or fiberglass. Fittings are usually not reinforced. When welding reinforced pipes, a layer with reinforcement is removed with a special tool - a shaver.

Tools and equipment for welding

Today there is wide selection specialized tools and devices for welding. Firstly, a welding machine, which has a body with a handle, a tip with holes for nozzles and a stand. On the case there is a switch, a temperature regulator, a heating indicator and a thermostat. The stand allows you to install the device on a table or fix it with a clamp to a suitable structure.

Secondly, these are special metal nozzles on the sting of the apparatus, for heating them on one side of the pipe, and on the other - the fitting. The nozzles consist of two parts and are heated from a sting to a temperature of 260 ° C - this is the melting point of polypropylene. The tips are Teflon coated to prevent plastic from sticking. Thirdly, . Cutting polypropylene pipes with them even with one hand does not require much effort. At the same time scissors provide squareness and purity of a cut. The internal passage of the pipe is not deformed. These and other tools fit into a case: a handy and practical welder's kit. Additionally, a shaver is purchased to use it to remove the outer layer of reinforced pipes. This set is designed for small amounts of work, for example, when installing water supply and heating in a private house. The diameter of the pipes welded on the nozzles of the apparatus is from 16 to 40 mm.

The process of welding pipes with fittings

If you try to connect the parts without welding, you will see that it is larger than the diameter of the fitting inlet and it is impossible to make a connection. The difference in size will be about 0.5-0.7 mm. And outside diameter the mandrel for the fitting is also slightly larger than its hole, as is the pipe, the diameter of which more holes sleeves. After the nozzles are heated and combined with them, the outer layer of the pipe is melted and internal fitting, with extrusion of the burr in front of the sleeve and mandrel. As a result of heating and removing the plastic layer from the parts, their diameters are aligned, and the pipe with the fitting already enters into each other and connects. The burr is visible at the junction of the fitting and pipe.

Pipes and fittings are pushed onto the nozzles until they stop, which is felt clearly enough by the hands to understand that the parts have entered to the desired depth. Since only the outer layer, approximately 0.4 mm, is melted, the solid base of the parts does not allow them to move further. In parts advanced to the stop, the end is also melted, which is very important in the future for strong connection. During the connection of parts, the formation of a single product occurs.

If parts are connected from different materials, then the formation of an integral part may not occur. The material may not weld if the surface of the parts to be joined was dirty and greasy. Then the connection will be fragile and leaky. The temperature set on the apparatus at 260°C is high, for melting polypropylene it could be 149°C, however, heat allows you to quickly melt only surface layer material without heating it to its full thickness. In order to obtain a strong connection of polypropylene pipes, as a whole, it is impossible to overexpose (overheat) pipes and fittings in the nozzles of the apparatus, just as it is impossible to underexpose. In the first case, excessively soft parts, when they move, can deform and reduce the internal passage or not connect at all. In another case, incomplete mutual displacement of parts is possible and, as a result, an unstable connection.

Preparation of parts and workplace

Technologically, welding has been worked out, and even in the welder's kit there are standard instruction, but more important is strict compliance with the requirements and rules for the production of work, on which the quality of the connections depends in practice. An assembly plan for a specific pipeline should be developed on site. Based on it, it will be known how many and what connections to perform on a permanently fixed apparatus, and how many of them will have to be performed while holding the apparatus on a canopy. Install it on a solid surface, such as a table. The tip should be directed away from the welder. Pipes are prepared by cutting them with special scissors of the desired length.

Reinforced pipes are treated with a shaver - removed reinforced layer at the place of heating. Ordinary pipes in places where it will be necessary to cook are degreased. This operation, which is important for the quality of welding, is skipped everywhere. Pipes and fittings are marked - applied conventions on the sockets into which the pipe will be welded. The orientation of the fitting sockets is marked on the pipe. The prepared pipes are folded on one side of the apparatus, and the fittings on the other. They screw nozzles onto the sting, three can be done at once. They are correctly oriented: the mandrel is fixed on the side where the fittings are folded, and the sleeves are on the side of the pipes. The nozzles are fixed before the device is turned on and tightened with a wrench.

Technology and sequence of welding

Turn on the device, set the heating regulator to 260 ° C, and wait until the desired temperature is set and the indicators go out. If the room is warm, then it will take 5-10 minutes to heat up, if it is cold, then welding can be done in 15-20 minutes. When the nozzle heating indicators turn off, the subassemblies for the pipeline begin to cook. They take the pipe in one hand, the fitting in the other. The fitting is put on the mandrel, and the pipe is inserted into the corresponding sleeve. With effort, as they heat up, they move the parts towards each other until they stop, which is felt by the hands. Now the pressure on the parts is reduced, keeping them in the position reached. The exposure time is a few seconds, then the parts are quickly removed from the nozzles and connected, inserting into each other until it stops, observing alignment. They hold it in their hands, fixing their mutual position for a while. The pipe diameter and time periods correspond to the data given in Table 1. Table 1. Time intervals for welding polypropylene parts.

The larger the pipe diameter, the larger the melting surface, respectively, the longer the warm-up period. Do not neglect the time intervals and risk the quality of the entire pipeline. It is not recommended to weld and simultaneously rotate the parts around the axis during heating, welding and fixing. Do not attempt to reorient the fitting or tilt it about its axis. This necessarily leads to a weakening of the weld and there will be a risk of leakage during the operation of the pipeline.

After fixing the connected parts, a new pair of parts can be welded. The time for one connection with a pipe with a diameter of 25 mm does not exceed 22 seconds. The device remains switched on for the entire duration of stationary welding. If there are two modes of operation, it is worth transferring the device to one of them to maintain the temperature. If the indicator lights up periodically, this sometimes happens in a cold room, then you need to turn on both modes. The temperature of the nozzles must be constant, 260°C, as required by the instructions and welding technology. next couple parts can be cooked, having previously examined the nozzles for the presence of adhered plastic, they must be cleaned with rags. If the diameter of the newly welded parts differs from the previous one, then other nozzles are used.

Ways with a diameter of 20 to 63 mm do not differ in anything, except for the time intervals (table 1). The number of connections, with a permanently installed device, on one subassembly is not limited. If it is difficult to hold the pipe or fittings in a certain position, an assistant for the welder is needed. At the wall, welding on weight must also be done with an assistant.

Proceed to the assembly of the pipeline itself. Part of the subassemblies is fixed with clips on the walls, and the other part will need to be welded in place. To do this, remove all the nozzles and fix one, the right one, at the end of the sting. This is done to facilitate the apparatus and to maneuver, since the wall has a shortage of space. If the temperature of the environment surrounding the place of work is negative, then welding is not carried out: there is a high risk of obtaining a poor-quality connection.