After listening to numerous pieces of advice, you decided not to hire craftsmen to install the heating system and make all the connections of polypropylene pipes yourself. If you are confident of success and are good at working independently, then feel free to start preparing and producing work.
We, for our part, will tell you what tools and accessories are required for installation and how to solder correctly polypropylene pipes. By default, we will assume that all the materials have already been purchased, all that remains is to assemble everything according to the scheme.
Welding machines for polypropylene pipes
Let's start by preparing the installation tool. Since all connections of PPR pipes and fittings are made by soldering, you will need a special soldering iron for this purpose.
Note. The joining of PPR parts is sometimes called welding. To avoid confusion, remember that when we're talking about Regarding polypropylene pipes, there is only one connection method - soldering, but it is often called welding. These systems are not installed using press or threaded fittings, like metal-plastic pipes.
The welding machine used for polypropylene pipes is offered on the market in two types:
- with a round heater;
- flat heating element.
The latter was popularly nicknamed “iron” due to some external resemblance to this household appliance. Different welding machines have no fundamental differences, only structural differences. In the first case, nozzles for Teflon pipes are put on and attached to the heater like clamps, and in the second case they are screwed to it on both sides. Otherwise, there is not much difference, and the device has one function - soldering polypropylene.
Soldering machines are usually sold complete with attachments. Cheapest and minimum set made in China - this is a soldering iron with a power of up to 800 W, a stand for it and nozzles for 3 sizes of the most common pipes - 20, 25 and 32 mm. If your heating scheme contains only such diameters and you do not plan to solder polypropylene pipes anywhere other than your home, or do it professionally, then a budget set will be quite enough.
If, in accordance with the calculation and diagram, you need to join pipes of sizes 40, 50 and 63 mm, then you will have to spend money and purchase another soldering kit, which contains the corresponding parts. Well, the most expensive kits are produced in European countries, they are distinguished by their reliability and durability. Similar kits include the following tools:
- soldering iron with stand;
- Teflon nozzles for soldering iron of all the above diameters;
- scissors for cutting pipes at a precise angle of 90º;
- hex wrench;
- Phillips screwdriver;
- roulette;
- gloves.
Important! Since soldering polypropylene pipes involves working with heated equipment, it is strongly recommended to always use gloves, regardless of whether they are included or not. This is especially true for beginners, who in 99 cases out of 100 accidentally touch the heating element.
The working part of a soldering iron (heater) of any design is designed in such a way that 2-3 nozzles for small-diameter pipes can be installed on it. This allows you to save a lot of time when working with lines ranging in size from 20 to 40 mm.
A little about the power of the soldering machine. High power is necessary for quick and uniform heating of large diameter parts, which are considered to be sizes 63 mm or more. For home purposes, it is enough to have an iron with a power of 0.7-1 kW. Soldering irons with heaters above 1 kW are considered professional, and accordingly, they are more expensive than regular ones.
In addition to the iron, you should prepare another tool for soldering polypropylene pipes; its composition is given above in the list. If you don’t have scissors for cutting the pipe at an angle of 90º, then for this purpose you can use a hacksaw and a carpenter’s miter box, or make it yourself, guided by the drawing:
Note. When there are no scissors for polypropylene pipes and they are cut with a hacksaw, then the end must be cleaned of burrs outside and inside the product.
Before cutting a section of the required length, it must be accurately marked. The fact is that when connecting, part of the pipe fits into a tee or any other fitting; this is called soldering depth. Therefore to required size area determined using a tape measure, you need to add the value of this depth by measuring its value from the end and putting a mark with a pencil. Since soldering technology provides for different immersion depths for different pipeline diameters, its values can be taken from the table:
Note. The table shows soldering depth ranges, since it varies within these limits among different manufacturers of PPR pipes. The value can be determined by measuring several fittings with a depth gauge.
When installing heating systems, reinforced polypropylene pipes are soldered; they differ from conventional pipes by the presence of a layer of aluminum foil, fiberglass or basalt fiber. Moreover, this layer can be made differently in products from different manufacturers. When the reinforcement is not located in the center of the wall thickness, but near the outer edge, then stripping will be required before soldering the polypropylene pipes. For this there is special device:
Welding process
Before you start working, you need to put attachments on the soldering iron that match the size of the pipes, and then turn it on and configure it. Here you need to know at what temperature to solder polypropylene pipes. Most manufacturers indicate an operating temperature of 260-270 ºС; you should not raise it higher, otherwise overheating cannot be avoided. Underheating is also fraught with poor-quality and leaky connections, where a leak will then quickly form.
It must be understood that heating time, product diameter and welding temperature are interconnected. In the table we indicate the welding time intervals at a standard temperature of 260 ºС.
Note. The duration of welding is the time until the plastic completely hardens, when the joint gains maximum strength.
When setting up the iron is completed, we proceed to welding, following the instructions for soldering polypropylene pipes:
- Taking the pipe in one hand and the fitting in the other, we put them on the nozzle of a heated soldering iron on both sides simultaneously, without turning them around their axis.
- We maintain the allotted time.
- Carefully remove both parts to be connected from the Teflon nozzle, again, without rotating.
- Smoothly insert the pipe into the fitting up to the mark without turning and fix it for the time indicated in the table, at this point the joint is ready. The operation is shown in more detail in the video:
It is more convenient to use the soldering iron correctly when it is installed on the table, so it is recommended to solder several practice joints first. After this, you can assemble all possible nodes with short sections in a convenient position. Next comes the laying of highways with the connection of tees locally; here it will be more difficult. A heated iron for soldering will need to be put on one side of the laid pipe, and the tee will need to be pulled on the other side, holding the device suspended. Then the soldering iron is removed from both parts and they are joined.
When laying main pipelines, follow the order of installation of sections and elements. Start assembling the system from the heat source and go to the end, and to connect two polypropylene pipes, try to use only tees, from which branches will go to the batteries. Use couplings for this purpose when it is impossible to do otherwise. Avoid joints in hard to reach places, otherwise to complete them you will have to work with two soldering irons at once in order to simultaneously heat the parts being connected.
Advice. Many manufacturers polypropylene systems are developing own instructions for installation of your products. You can get a lot of useful information from there, take advantage of it.
How to connect a metal-plastic pipe with a polypropylene pipe
Due to various circumstances, it happens that it is necessary to connect different kinds pipes, for example, PPR and steel, metal-plastic with polypropylene and so on. Such situations happen in apartments where it is difficult to change a section of a common water supply or heating riser laid with a steel or metal-plastic pipe, but you need to connect to it. This is not big problem, you just need to take into account that all such connections are made through threaded fittings.
Since metal-plastic pipes can be connected using press and dismountable fittings, for joining with polypropylene it is more convenient to take a detachable fitting with external thread. In turn, a fitting with an external thread is soldered to the end of the polypropylene pipe, after which the connection is twisted in the traditional way, with flax or fum tape wound up.
When you need to cut into metal-plastic pipes, it is most convenient to install a tee with a threaded outlet, where you can subsequently screw the fitting, and then solder the polypropylene pipe to it. True, you will have to tinker with the installation of the tee: you need to turn off the water or empty the heating system, and then cut the metal-plastic and carry out the installation.
Conclusion
It should be noted that working with polypropylene pipes is not the most difficult task, although it requires concentration, attention and patience. Even if you spend three times as much time on the process as experienced professionals, you will do everything for yourself with high quality, and most importantly, for free.
Plumbing and heating system are integral elements of any modern apartment or at home. The basis of these systems are pipes. To replace traditional cast iron and steel structures More durable and easy-to-install polypropylene plumbing and heating structures are coming. They are plastic, easy to repair or replace, and are not subject to corrosion.
The correct choice and proper connection will ensure the durability of plumbing and thermal heating systems.
Main types of polypropylene pipes
The selection of pipes directly depends on their intended use. The main parameters are considered to be: the temperature of the medium that will be carried through the pipeline and operating pressure systems. The diameter of the pipeline is no less important, and it depends on the volume of liquid that the pipeline must pass.
For cold water supply pipelines, pipes without a reinforced component with the following markings are used:
- PN 10 - the product is designed for liquid temperatures up to 20 degrees when used in underfloor heating systems up to 45 degrees with a maximum system pressure of up to 1 MPa;
- PN 16 - the product is used in cold and hot water supply at liquid temperatures up to 95 degrees and pressure up to 1.6 MPa.
Products with higher thermal characteristics and the ability to work in cold and hot water supply systems with high pressure are marked with the following indexes:
- PN 20 are used in temperatures up to 95 degrees and maximum pressure up to 2 MPa.
- PN 25 are used in hot water heating systems. They have a reinforced component, which significantly increases strength. Operating temperature up to 95 degrees and maximum pressure up to 2.5 MPa.
In addition to pipes, the installation of the system requires connecting elements that allow you to create a complete heating or water supply system, taking into account all necessary requirements for each individual case.
Fittings and couplings - types and purpose
When laying a water pipeline to connect sections of the water main special couplings and fittings are used various forms
. They are straight and angular.
For branching, branching fittings of various configurations are used, as well as fittings for transitioning polypropylene pipes to other connectors of the water supply system, for example, flexible connections leading to drainage points, taps, and mixers.
Before installing a plumbing or heating system a drawing is drawn up that takes into account all turns, branches and connections to consumption sources. This is great for calculating required type and the number of couplings and fittings. After acquiring all the elements, the installation of the structure begins.
Welding tools
The soldering technique involves heating the material of the surfaces to be joined until it melts, followed by joining and fixing. To carry out this work, you need to prepare special tools.
- Specialized soldering iron.
- Scissors for cutting polypropylene pipes.
- A device for cleaning the reinforced part of pipes is a shaver.
- Alcohol based degreaser.
You will also need a tape measure, a knife, a corner, a piece of unnecessary rag, a file or sandpaper, and a marker.
Soldering iron
This basic tool required for soldering polypropylene products can be of two types:
- Manual type Designed for soldering parts of pipelines with small diameters up to 65 mm. There are two types: cylindrical and sword-shaped. Used for domestic purposes, it is characterized by low cost and compact appearance.
- Mechanical type - these are automatic or semi-automatic welding stations for the installation of large diameter pipes over 63 mm. Centering and connection of elements occurs using special devices on hydraulic or mechanical principle actions. This soldering machine is large in size and expensive, and is intended for use both indoors and in the field.
To install a heating network or water supply in an apartment or house, use a hand-held soldering apparatus and attachments for it. The nozzles are included with the soldering iron and have various sizes, meeting the standards of manufactured pipes with a diameter of up to 63 mm. Each nozzle corresponds, on the one hand, to the internal diameter, and on the other, to the external diameter of a pipe of a particular standard. The nozzles are coated with Teflon coating. This makes it easy to release the heated part of the products for subsequent soldering to each other.
Scissors
A tool that allows you to cut a polypropylene product at an angle of 90 degrees relative to the pipe length vector, while maintaining a straight cut edge. This is very important for the reliability of soldered connections.
Shaver
This is a device for properly stripping the reinforced layer. Allows you to smoothly and to the required depth the outer diameter of the product to pure polypropylene on pipes with top reinforcement.
Degreaser
Necessary for high-quality melting of products and hermetic connection of the structure.
Soldering polypropylene pipes is not difficult, but requires care and precision in meeting a few technological requirements. How to properly solder polypropylene pipes will be discussed below. The elements are connected by socket soldering with simultaneous heating of the outer part of the pipe and the inner part of the coupling or fitting with a soldering apparatus using a nozzle corresponding to the size of the elements being soldered.
After heating to desired temperature the parts are removed from the nozzle and quickly connected to form a monolithic unit; in other words, they are fused together. The method is called diffusion, since after heating the parts can be seamlessly connected. After hardening, a tight connection is formed. For quality correct connection pipeline elements will need to carry out a number of preparatory work.
How to solder pipes
Preparation
Before installing the pipeline structure, you need to cut the pipes correctly so that there are no problems with joining the elements. All material cuts must be made with scissors at an angle of 90 degrees. They make it possible to make the most accurate cut with a smooth edge.
Then you need to mark the dimensions of the connecting surfaces. To do this, determine the heating depth of the fitting or coupling by marking the depth of the nozzle with a pencil or marker. A mark of the same size is made on the pipe.
Preparing the soldering iron involves installing the device on a working stand. Nozzles corresponding to the diameters of the mounted parts are attached to the heating surface. The mounting elements should fit relatively easily into the heated nozzles.
On the soldering iron temperature control regulator optimal temperature is set heating, it is usually 210-260 degrees, polypropylene begins to melt at 170 degrees. The parts to be joined are simultaneously put on the heated nozzles to the depth marked with a marker.
After waiting for the surfaces to soften (the time required for this can be determined using special unified tables), the parts are connected to each other to the marked depth. The elements are connected with little force, but without rotation along their axis - this is Absolutely forbidden and will break the tightness of the alloy of heated surfaces.
Installation temperature parameters
The soldering temperature for polypropylene pipes depends on the diameter and thickness of the product and starts at 170 degrees. For the convenience of calculating heating time, there are special tables. Below are the time parameters for heating the main diameters of pipes used in the installation of home heating networks or water supply systems at a heating temperature of the soldering unit of 240 degrees.
Using the parameters of optimal heating, joining and cooling of the elements being connected, we achieve reliable soldering of polypropylene pipes and other components pipeline.
Cold water supply pipelines
For the installation of cold water supply, you can use any polypropylene pipes, including grades PN 10 and PN 16. These models are thin-walled and require careful handling when joining the molten parts; minimal force is applied to connect them. It is also necessary to strictly observe the time required for heating the parts of the connection. For cold water supply, as a rule, non-reinforced pipes are used, so additional processing of the connecting ends is not required. Before starting installation of the main structure, it is better to first make several test connections to select optimal temperature heating the soldering iron.
Heating mains and hot water supply pipelines
Hot water passing through the pipes causes a slight expansion of the material and, as a result, an increase in the length of the product. To compensate for this phenomenon during installation, it is necessary to make U-shaped bends in the line from time to time. High water temperature also requires installation of specialized reinforced pipes, which are manufactured slightly larger than the diameter required for joining. Carefully trim off the excess layer of material with a shaver. This is necessary to compensate for expansion across the width of the pipe when heated. Further actions occur in the same way as when connecting a cold water supply.
Repair of failed sections of the highway
When a pipe ruptures, leaks, or as a result of poor-quality soldering, sometimes it becomes necessary to replace the failed section. To do this, turn off the water supply and cut out the damaged area with special scissors. At the cut points, the edges of the pipes must be dried, cleaned and wiped with an alcohol-containing degreasing liquid. Only after this do they begin to weld a new, serviceable piece using the methods described above, depending on the temperature carried through the water line.
Cold welding method
This method of connecting highway elements is suitable only for cold water under slight pressure. The joining surfaces are degreased. A special glue, sold in construction stores, is applied, the elements are joined and fixed for thirty seconds. The water supply will be ready for use in only an hour. This method is not reliable and does not create a monolithic connection of parts.
Polypropylene pipes are a good alternative to classic steel or cast iron lines. Installation of water and heat supplies with their help is simple, not labor-intensive and cheap. Therefore, these products have taken their large and rightful place in their segment of the construction market.
The welded connection of polypropylene pipes is characterized by higher reliability compared to other methods of combining products with each other. This connection technology does not have any differences when working with polypropylene. The only exception is reinforced products: their installation requires some specific features.
This technique is quite simple. Welding can be carried out at home, observing the requirements of the technological process and having the entire arsenal of necessary tools.
There are several options for connecting polypropylene pipes:
- diffusion soldering;
- soldering with electrical fittings;
- cold welding.
In this article we will talk about each method of combining cylindrical products in more detail, consider their advantages and disadvantages, and also learn how to properly solder polypropylene pipes.
Before you begin, you need to prepare the installation tool. To create a reliable joint between structures and all additional details you will need a special soldering iron.
It is worth noting that sometimes the connection of products made of polypropylene is called welding. However, this process has many varieties, so it is important to remember that polypropylene pipes are connected in only one way - soldering. For the installation of such a system, threaded fittings and metal-plastic are not used.
Soldering polypropylene pipes requires the use of welding machines. There are several types of devices on sale:
- heater with a round cross-section;
- flat unit.
The second type of soldering machine is popularly called an iron, which is largely due to its appearance. Such devices differ only in their design.
For the first model, Teflon nozzles are put on the heater and fixed with parts similar to clamps. In the second device, the same nozzles are screwed to the heater on both sides. The rest of the design elements are no different. The main function of the device is to perform high-quality and reliable soldering of polypropylene products.
The set of soldering devices must include nozzles. The most inexpensive device, the set of which includes a minimum number of elements, is considered to be a Chinese soldering iron. Its power does not exceed 800 W. It is presented for sale together with a stand, as well as attachments that allow soldering of PP pipes with a cross-section of 20-32 mm.
When the heating system of a private house is made of cylindrical products of this diameter, this kit will be quite sufficient. But if more is expected professional work soldering related problems, you'll need a better device.
For pipes with a cross-section of 40-63 mm, a different soldering kit is required. It will have to be purchased separately. The most expensive sets, characterized by increased reliability, are manufactured in large European countries. Their kit includes the following parts:
- soldering iron;
- stand;
- Teflon nozzles of different diameters;
- scissors that allow you to cut pipes at 90 degrees;
- hexagon;
- Phillips screwdriver;
- roulette;
- gloves.
Since you have to work with hot equipment to solder polypropylene pipes, you must wear gloves when performing the operation. Beginners often get burned when touching the heating element.
The design of any soldering iron is designed so that it is possible to install several nozzles at once for connecting small-diameter pipes, which saves time, especially when working with products with a cross-section of 20-40 mm.
Soldering machine power
To evenly and quickly heat a pipe with a diameter of 63 mm, greater system power is required. For domestic purposes, a device with a value that determines the amount of energy not exceeding 0.7-1 kW will be sufficient.
If the power of the iron is more than 1 kW, it becomes professional. Its cost is much higher than the price of an ordinary soldering iron.
Method one
For the manufacture of homemade soldering iron you will need:
- a broken old iron that still has a heating element;
- children's metal construction set;
- rubber handle;
- toggle switch;
- asbestos cord;
- duralumin;
- insulating tape.
Manufacturing technology
- use a grinder to cut off all unnecessary parts from the bottom of the iron;
- an aluminum cover is made;
- a box is assembled from the construction kit; a light bulb and a rubber handle are installed in it;
- a toggle switch and a soldering iron regulator are connected to the wire;
- all parts are combined into one whole;
- cables are soldered;
- The heating element is bolted to the body, having previously placed an asbestos gasket.
Thus, after spending a little time using available material, you become the owner of a homemade soldering iron for welding PP pipes.
Method two
To make the tool you will need a pair of attachments costing 215 rubles. and a discarded, set fire iron. It takes approximately two hours to assemble.
First, the heating device is installed vertically. The fitting is placed on the heating nozzles simultaneously with the pipe. To make it possible to carry out operations on the wall, the iron needs to be slightly modernized: cut off the “sting” of the sole and slightly round it. It would be a good idea to use thermal paste.
It is known that such homemade device several pipelines were welded. The quality of work turned out to be quite high.
After heating the iron, holding it by the handle, remove the pipe first. There is no need to remove the fitting immediately, since its thickness prevents it from melting quickly. All that remains is to hold the pipe with the iron with your hand and remove the fitting.
To connect the products, you need to apply little force until an even flash is formed around the entire perimeter of the fastener.
You need to hold the connection in this position for about 15-20 seconds until polymerization begins. Welding on the wall is simple: hold the heating device with one hand, and the pipe with the other.
Method three
We manufacture an iron equipped with a temperature controller, which will act as a special power control device assembled on a thyristor. For soldering work a voltage of 170V is supplied. Aluminum or copper plates are used to create the device. The photograph shows a part with a thickness of 0.8 mm, but the value of this value may vary upward.
Flat elements are needed so that the heater does not begin to cool the moment the pipe is put on. For operation, a heating element (1 kW) from an outdated Mechta stove is used. Since the radiator hardly heats up, it can be reduced. No spacers are required to install the thyristor and diode. The design of the iron itself can have any shape, it all depends on your imagination.
Below is power regulator circuit.
On each side of the spiral you can install aluminum spacers in the form of round pancakes. A handle with a regulator and a fixed toggle switch is attached to the body. In other words, you can do tuning.
The principle of all devices is always the same: to solder PP pipes, you need to maintain a certain temperature.
How to choose nozzles
When selecting heating nozzles, it is necessary to take into account the diameter of the pipes being connected and other important points:
- strength;
- how well the shape is retained after temperature changes;
- thermal conductivity.
Almost all welding machines are suitable for various attachments. This is very convenient when you need to install a complex highway.
Each wearable element has two ends. On one it heats up outer side details, on the other - its internal part. All nozzles are coated with Teflon, which protects the surface from the adhesion of molten material. The dimensions of the parts are in the range of 2-6 cm, which corresponds to the common diameters of cylindrical products.
Normal temperature for soldering
For durable welding of structures, the soldering temperature of polypropylene pipes should not exceed 260 °C. Otherwise, this will lead to loss of stability of the plastic base, as a result of which the pipe simply will not be able to connect to the fitting. And heated connecting element will begin to stick to all parts surrounding it. However, a lower temperature is also not suitable for soldering.
It is important to remember that the viscosity and plasticity of the polypropylene structure must have certain values, otherwise diffusion processes will not begin and the connection will lose its reliability. The service life of such pipelines will be minimal. You will have to forget about the 50-year warranty. It is better to look at the table at what temperature to connect the products.
Pipe soldering time
If you correctly follow the technology requirements for the duration of the process of connecting structures using a special tool, you can get a fairly airtight joint. Polypropylene will not begin to spread after overheating. Heating time depends on certain parameters. The main ones are:
- pipe section;
- welding belt seam width;
- ambient temperature.
Below is a special table that shows the recommended soldering time for PP products, taking into account all the values mentioned above:
Socket welding of polypropylene pipes
The main method of installing plastic when you need to connect small cylindrical products different sections, the use of a bell is considered. When welding a PP structure, additional parts must be used:
- corners;
- tees;
- bends.
They are all made from the same material from which the pipes were made. Application additional elements to create a high-quality connection is not considered a disadvantage of this method. The parts in question, in addition to the connecting function, help change the direction of the pipeline.
This process consists of several operations:
- the mating surfaces are melted: the outer wall of the cylindrical product with the inner part of the fitting;
- special heating parts are used;
- The assembled elements are cooled.
According to professionals, socket joints are considered much more reliable than butt welding. Due to the fact that when combined, the pipe enters the fitting with force, high strength is created. In this case, alignment does not require the use of a special tool. Even a beginner can combine cylindrical structures in this way.
Socket welding machine
Devices designed for connecting PP products into sockets are called soldering irons or irons. The main element of such a device was the heating head. All replacement parts are attached to it:
- couplings;
- dorns.
The first elements are designed to heat the outer surface of the pipes, the second - the inner part of the fittings. The shape of the heater in most soldering irons remains a triangular plate. Devices of other designs can be found on sale.
The size of the nozzles depends on the dimensions of the flat part. In other words, a pipe section is selected that will be freely soldered. In addition, you need to take care of the right quantity heating couples for simultaneous installation. To work with a large plate you will need a powerful unit.
Additional parts (couplings, mandrels) must be secured so that their supporting surface tightly touches the plate.
At good contact the required temperature (260 °C) will be reached. In this case, the power of the soldering iron does not matter much.
Today, devices are produced equipped with a heating head in the form of a rod. Their main advantage can be called compactness. The head shape does not affect the technical parameters.
For quality work When using an iron, the accuracy of the temperature sensor, which maintains the required temperature, is important. If its fluctuations become minimal, this indicates high quality soldering iron
The most advanced today are electronic thermostats. These thermistors are capable of displaying an accurate temperature value even at work surface couplings.
The use of such parts makes it possible to reduce the temperature inertia of the iron. As a result, the true readings of the heating head will be displayed on the device scale.
Bimetallic relays work more roughly, as well as capillary thermostats, whose values are inaccurate. If compared with the data from thermistors, the discrepancies will be quite large. Whatever the thermostat, when the device reaches operating mode (judging by the indicator data), you must wait a few minutes. During this time, the temperature of the nozzles will be compared with the one shown by the device.
Now you can start welding. Manufacturers also produce soldering irons that have two heating elements of different power. Each part is equipped with a separate switch.
These products are able to independently achieve the desired temperature. The master himself selects the required power.
The second part becomes a spare in case the first one fails.
The device provides the ability to simultaneously turn on both heaters in order to quickly achieve operating mode.
The equipment can be equipped with auxiliary tools, including:
- chamfer;
- calibrator;
- trimmer;
- pipe cutting scissors.
In some kits you can even find a special cleaning liquid. However, not all of the listed parts are included in the basic package. Often they have to be purchased separately. It is important that the welding machine comes with everything necessary tools for working with any pipe diameters and materials.
Technological process of socket welding
The outer diameter of a cylindrical product is always slightly larger than the nominal cross-section. The fitting, on the contrary, has an internal diameter less than the nominal cross-section of the pipeline.
Let's take, for example, a 20 mm pipe. The actual size of its outer diameter will be in the range of 20.3-20.5 mm. For a fitting designed to work with a 20 mm product, internal section will be 19.5-19.7 mm.
Moreover, the middle part of the coupling surface will exactly correspond to the nominal diameter. For a conical plane, 5 degrees are taken.
It becomes clear that if the fittings are not heated, they will not be able to be connected to the coupling.
When the pipe is combined with a hot coupling, melting of the outer part occurs. All excess is squeezed out to the top, creating a kind of roller. Next, the inner layers are heated. They begin to compress, and the pipe is able to get into the hot sleeve. A similar effect can be achieved when the fastener element is connected to a hot mandrel.
When the pipe is combined with the fitting, it is elastically compressed, and the connecting element begins to stretch. Heated surfaces are compressed, displacing air. The result is uniform mixing of the molten material.
General technological process Connecting PP pipes into a socket has several sequential operations:
- cutting of products;
- preparatory activities;
- installation of a welding machine;
- achieving operating mode;
- warming up parts;
- assembly;
- line cooling.
You can manually connect a pipe with a heated tool without much effort if you are welding small parts whose cross-section is in the range of 40-50 mm. To combine cylindrical structures with a diameter exceeding 50 mm, you must use a special centralizer designed for socket welding.
Since soldering polypropylene pipes does not represent special labor, the work can be done alone.
To cut cylindrical products, special scissors are used that do not allow the pipe walls to wrinkle.
Before starting to solder polypropylene products, the surfaces of the parts are thoroughly cleaned and degreased. Reinforced structures undergo special preparation. Workers installing such products must remember this.
Composite pipes made of PP, which are reinforced with aluminum, are characterized by low thermal expansion. Therefore, a heating system made from such products does not require the installation of additional temperature compensators. Only in such products reinforced with aluminum is oxygen diffusion possible. After air enters the system, the water is actively saturated with oxygen. As a result, the process of cavitation of valves, as well as other parts of the structure from cylindrical structures, begins.
In the absence of a reinforcing layer, there is no need to carry out additional special preparation.
Technological map for socket welding of polyethylene pipes
How to solder reinforced polypropylene pipes
In this case, contact of aluminum with liquid is strictly prohibited. This alloy begins to deteriorate, and buying new products is unprofitable. The appearance of small internal distortions in the joints is difficult to notice with the naked eye, however, it is these zones that are the weak point of the entire system. Here it is possible for water to get on the metal surface.
To prevent this, clean thoroughly reinforced layer. Such an operation is mandatory if the surface of the pipes is wrapped in foil.
To remove the metal sheet, a special device is used - the so-called shaver. It has to be purchased separately.
The end is inserted into the device, similar to sharpening a pencil, and they begin to turn.
When working, do not forget about cleaning the aluminum layer. Welding will occur without this procedure, but the reliability of the resulting connection will be quite low.
You can get rid of this human factor by installing fiberglass-reinforced pipes.
If the aluminum reinforcing layer is located in the center of the wall, the surface is trimmed using a special tool. It helps remove the edges of aluminum that cover the end of the pipe. If such an operation is not carried out, water can get into the center of the wall, moving along microcracks in the reinforcing layer, which will inevitably lead to swelling. 
In the photograph you can see the soldered connections of the cuts: the incorrect execution in the picture without trimming and the correct one - with trimming.
To achieve the best results, special couplings are used. They seem to “brick up” the ends of the reinforcing layer, which helps to avoid contact of the metal with the liquid.
Some manufacturers give their own recommendations on how to prepare pipes before welding. Even if there is no reinforcing layer, it is necessary to calibrate the outer diameter and then remove the chamfer.
The sizing operation removes the ellipse of the pipe, making it completely round. Chamfered facilitates the work of connecting to the coupling. Unfortunately, when PP pipes are soldered independently, these operations are completely ignored.
How to prepare a soldering iron for use
First, the welding machine must be firmly secured. When heating begins, the parts are subjected to pressure, which is transferred to the soldering iron. To make it more convenient to work, it is important to ensure that the device remains stationary.
A heating couple is placed on the instrument. Next, the desired heating temperature is set and voltage is applied. When PP pipes are socket welded, the heating temperature should be within 260±10 °C, which exceeds the values at which polypropylene becomes viscous and fluid.
In this way, the top layer of the pipe together with the fitting quickly melts. As a result, the part can be easily removed without heating the entire wall thickness. At a different temperature, when the elements become soft, the connection will not be possible.
We put the parts to warm up
When the welding machine reaches operating mode, the light will light up. The pipe is inserted into the coupling, and the fitting is inserted into the mandrel. If it is quite difficult to carry out such work at the same time, a heavy connecting element is installed first.
Welding parts necessarily have a small allowance, which begins to squeeze out during their installation. This creates a ring-shaped roller (burr). To move such a ring, you need to make some effort, but this should be done smoothly and slowly so that the burr takes on the correct shape. A fitting that fits loosely onto the mandrel and does not form an annular bead is considered defective.
When installing the part, be sure to monitor the installation depth. As soon as the element rests against the top of the mandrel, the pressure must be stopped, otherwise the end of the pipe can be damaged and the fitting stop can be dented. To control the depth of immersion of the part into the coupling, a corresponding mark is made at a certain distance from the end. However, this procedure is not necessary since the fitting is basically inserted into the mandrel until it touches the stop.
After the parts have been installed in the apparatus coupling and its mandrel, you need to wait a few seconds until the surfaces are well melted. It is important to determine the heating duration correctly. This time should be enough to obtain a viscous and fluid state of polypropylene.
If the heating period is too long, the parts will become very soft. Manufacturers plastic pipes We have developed special tables that indicate the heating time for a certain brand of polypropylene. In this case, the wall thickness and cross-section of the pipe are also taken into account.
When fittings are combined with cylindrical products, the angle of rotation of the parts should not exceed 5 degrees. If the joint is made correctly, the flash will have the same thickness on all sides.
Cooling the connection
If it is necessary to correct the work performed, the technology allows this to be done within a few seconds. The parts should not be subjected to any pressure until the material has completely hardened, which lasts approximately 2-4 minutes.
Approximate parameters for the duration of welding operations can be viewed in a special table. More accurate values are indicated by manufacturers of fittings and PP products.
When soldering PP products end-to-end, the ends of the parts are heated with a hot tool until they melt. Then the elements are pressed with force until the seam cools. This technology is distinguished by its simplicity.
In this case there is no need to use additional accessories. If everything is done correctly, it turns out pretty reliable seam, not inferior to the strength of the pipe. The technological operation is performed in a certain sequence:
For all its simplicity, butt welding only seems so accessible. In practice, this requires solving several problems, which is almost impossible to do in everyday conditions.
The pipes must align exactly along their axis, with only a 10% deviation from the wall thickness allowed. Pressure on the parts that press cylindrical products to the plane of the heating mirror when exposed to high temperature should be applied only for a certain time. This is the only way to achieve a high-quality connection. When performing trimming, it is necessary that the end has perfect perpendicularity.
The conditions listed above are quite difficult to follow without an additional device - a special centralizer. It is equipped with an electric drive that creates a certain compression force. In addition, this device is equipped with a trimmer.
In other words, to carry out butt welding of small-diameter polypropylene pipes, you will need a larger amount of special equipment compared to the previous joining method. Considering the fact that when socket welding, a better joint is obtained due to the locking connection, home craftsmen prefer to use this particular method of combining pipes.
Butt welding of PP products is mainly used in production, when it is necessary to connect structures of large cross-section when installing a straight section engineering structure from cylindrical products.
Soldering of polypropylene pipes occurs in a fairly short time; this is the most attractive side of a polypropylene pipe. Due to its low price, manufacturability and ease of joining, it has taken a leading position among pipes made from competing materials. Mainly used when laying water supply and partially thermal engineering networks. And let strength give way to communications from metal pipes, but when starting renovations in an apartment or house, they give preference to this material. Pipes are reliably, firmly and quickly connected by soldering in a matter of minutes.
Polypropylene pipes are becoming increasingly popular due to their ease of installation and reliability.
Types of polypropylene pipes
The plastic used to make the product is highly durable. It does not rust, does not accumulate salt, and limescale does not stick to it. Networks assembled from polypropylene are designed for a long service life (up to 50 years). In fact, the service life of pipelines is not limited unless it is exceeded technical specifications operation by temperature or pressure. The material of the parts is capable of working for a long time for enough high blood pressure at low liquid temperatures, and vice versa.
Polypropylene pipes are produced in four colors; color means nothing but color. Polypropylene is allowed to be used in water supply, sewerage and heating systems. It is allowed to connect plastic with metal and make transitions.
Polypropylene products are divided into categories: PN10 - this category is established for thin-walled products. Application is limited to operating temperatures of 45° and for cold water. PN16 – category approved for use in pipelines with high pressure cold water or at heating system no pressure. PN20 is the most universal option; this category applies to both cold and hot water– up to 80°. PN25 is a reinforced category of polypropylene pipe, aluminum foil is introduced into the composition, due to this the application is expanded to a temperature of 95°.
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Soldering technology for polypropylene pipes
According to the technical manual for welding work on polypropylene pipes, if the diameters of the pipes being connected are less than 63 mm, then soldering using the socket welding method is used. A fitting is installed at the junction; this is a special part to which both pipes are welded. For pipes with a diameter larger than the specified one, a fitting is not required; they are butt welded. This connection is considered more reliable.
Produced by the machine manual welding- “iron”.
When welding is performed on pipes of 40 mm and above, it is better to use welding machines with a centering device.
The work is somewhat more difficult, but it is necessary.
The welding machine is designed as follows: it has special removable nozzles for pipes, which are heated by electricity. The nozzles are made like a sleeve that melts the outer edge of the pipe or heats inner part connected parts.
Nozzles are carried out various diameters– from 14 to 63 mm. To prevent burning, the heating parts themselves are coated with Teflon. When performing welding work, constantly monitor the cleanliness of the nozzle. It is necessary to erase traces of plastic after each welding, preferably with special rags or wooden scrapers. You need to clean it before the heating element cools completely; trying to clean cold elements can damage the Teflon layer.
When water communications consisting of plastic pipes are assembled, the most important parameter the temperature rises. It must have certain values to achieve a strong and reliable connection.
Today, the technology for laying pipelines made of such materials requires compliance with a certain temperature regime, as well as specific time values, when performing welding work. If you do not follow the recommended parameters, a rupture may appear in key areas and the movement of the water flow may deteriorate significantly.
The technological process of welding polypropylene pipes is based on heating the material to the required temperature. As a result, the plastic begins to soften. When connecting parts, diffusion of polypropylene molecules occurs. In other words, molecules merge into a compound. When the material cools, an extremely strong joint is formed.
The strength of the workpieces being welded is directly dependent on the temperature regime. If the heating is insufficient, the diffusion process will not occur. The molecules of the fitting and the pipe being welded are simply not able to get into the compatible areas. The welding will be weak and will not be able to withstand heavy loads. The pair will break and the seal of the joint will be broken.
When overheated, the structure will begin to deform. As a result, the original geometry will change. A strong influx in the form of a large roller may form inside the part. As a result, the cross-sectional diameter of the pipeline at the welding site will be significantly reduced.
For normal soldering of polypropylene pipes, it is necessary to create heating to a temperature of 255-265 degrees. The heating process must take into account several parameters:
- Part diameter.
- Room temperature.
- Heating time.
Practice has shown that heating time and part diameter are directly related.
The temperature of the room in which soldering occurs also affects this process. When parts are soldered, when removing them from the “iron” or other heating device, there is a pause before the coupling begins. To compensate for cooling at low temperatures, pp pipes need to be heated a little longer. This additional time is within 2-3 seconds. The selection occurs empirically.
It must be remembered that if you heat polypropylene pipes on a heating apparatus with a temperature setting of more than 270 degrees, the top layer of the part will become very hot. The core will not receive sufficient heating. When joining parts, the thickness of the welding film will be very thin.
How to weld polypropylene pipes manually
Welding sleeves of the device are selected taking into account the diameter of the parts. They are then inserted into the welding mirror and secured well.
Contact surfaces are cleaned of dust and dirt. For cleaning, it is better to use a cleaning fluid recommended by the manufacturer of this product. The following may help with this work:
- Chlorethylene.
- Trichloroethane.
- Ethyl or Isopropyl alcohol.
A certain temperature of the device is set. Typically, the thermistor should heat up within 250 - 270 degrees. This optimal value temperature allows the correct connection to be achieved.
When the thermostat reaches the desired thermal level, the heating temperature of the welding mirror is checked. For this, a special thermal probe is used.
The pipe is cut, maintaining 90 degrees relative to the axis. If necessary, you need to clean the surface and chamfer it. Stripping parameters and chamfer depth dimensions are taken from table number one. The chamfer can be removed when cleaning the part or after it, using a special calibrated tool.
Polypropylene fittings for socket welding. Grinding depth and chamfer width.
The insertion depth “L1” is marked on the surface of the pipe. Taken from Table 2. The stripping must necessarily correspond to the insertion depth.
Insertion depth L1(mm): maximum insertion depth of the heated pipe into the fitting cup.
A longitudinal mark is applied to the outer surface of the pipe and fitting being welded. It makes it possible to avoid displacement of parts during connection.
The surface of the pipe, as well as the attached fitting, must be well cleaned of oil or dirt. After achieving the required heating of the welding mirror, the pipe, together with the fitting, is installed in special sleeves. The fittings must be inserted all the way, the pipe being welded to the full stripping depth. You need to wait a little while the parts heat up.
They are then quickly removed and inserted into each other. The insertion depth of the fitting must be equal to the length L1, in accordance with the longitudinal notches.
The connected parts must be kept in a fixed position for a certain time, according to table No. 3. Then you need to give it time to cool naturally. Do not cool them with a fan or immerse them in cold water.
When the surface of the elements has cooled sufficiently, it is necessary to conduct a hydraulic test.
The changes in pressure and temperature during the butt welding process are shown in the figure below:
The nuances of maintaining the desired thermal regime
When calculating the future pipeline layout, figure out how further installation will take place. It is necessary to strive to obtain a minimum distance between the soldering machine and the connection point.
If the calculation is made incorrectly and the welding site is in an inaccessible place, you will have to heat the part at a considerable distance from the fastening site. In this case, large heat losses occur, since parts have to be transferred in order to make the coupling joint. As a result of such unaccounted for moments, a strong weakening of the seam occurs.
If an incorrect calculation of the installation and soldering sequence is made, a situation may arise when it is impossible to join the last parts, since the heating device simply cannot be installed between the parts. To increase the gap, it is necessary to deform certain sections of the pipelines that allow the soldering device to be inserted. This kind of work can ruin appearance communications. Static voltage may appear in some areas of the system.
A very serious mistake, as a result of which it is not possible to control the temperature, is the sequential heating of the workpieces immediately before the joint. In other words, each part is heated separately. As a result, the temperature regime is completely disrupted.
This incorrect approach can cause the part to cool down greatly due to the time it takes to warm up. Intentional loss of heat occurs. This method of connecting parts does not allow the work to be structured correctly and the process of softening the material becomes unpredictable. Its use is strictly prohibited.
To exercise proper control over temperature conditions, several criteria must be taken into account:
1. The quality of the welding machine for working with polypropylene products should allow it to hold certain parameters with minimal error.
2.Between welding machine and the connection area must be less than 1.5 meters.
3.The operation must be performed in a heated building.
4.Before starting welding, make sure that the temperature of the parts to be joined is approximately the same.
