With modern construction, almost 70% of pipes are made of polypropylene. They are used not only in laying new pipelines, but also in repairing old systems. During installation of the system, the technological rules of welding must be observed and, in order to achieve the best results, all nuances should be taken into account, including the temperature of welding of polypropylene pipes.
The scheme of polypropylene pipe with aluminum coating.
Properties of polypropylene pipes
This type of pipe is currently the most common, as these combine excellent technical qualities and low price. Polypropylene pipes are strong, durable and can resist corrosive lesions.
Possessing such qualities, polypropylene products can find application in various fields:
- when laying water and gas pipelines;
- for drainpipes;
- for removal and transportation of various aggressive liquids.
The following set is required for welding of polypropylene pipes:
Technical parameters of welding (soldering) polypropylene pipes.
- scissors for cutting pipes;
- degreasing agent;
- old rags from natural fibers;
- tape measure; marker;
- A special device for welding polypropylene elements with a diameter greater than 50 mm.
Also, when working you may need tools at hand: a knife, a handsaw for metal, if it is not possible to work with a pipe cutter or scissors.Back to table of contents
Preparation of the device and material for welding of polypropylene pipes
Before you start welding polypropylene pipes, it is important to properly prepare the equipment.
The first step to the welding device is to firmly secure the heating nozzles. Using the thermostat, set the temperature to 250-270 degrees and connect the device to the power supply. The right time for heating the device is set according to the temperature in the room. To prevent damage to the working layer of the nozzles, they must be cleaned with a cloth before heating.
Welding can be started if the required temperature is displayed on the indicator or contact thermometer.
Before starting the welding of polypropylene pipes, it is necessary to conduct a visual inspection, since the surface layer of the elements must not have any defects, the fittings must be in working condition. All threads must be checked with products with opposite threads.
The device for the soldering of polypropylene.
Pipes and fittings must be thoroughly cleaned and degreased. All fittings should be checked for tightness. Fittings that stagger and sit poorly are rejected.
All pipes must be carefully measured and cut. If they are cut off with a hacksaw, the edges should also be treated for burrs.
Using equipment designed for this purpose or a sharp knife, the pipes are cut off at the end of the weld edge to about 45 degrees. These manipulations are mainly carried out with products of large sizes (cross section over 40 mm). This cut is required to avoid material stratification when inserting the pipe end into the fitting.
Before starting the spikes of volumetric elements, it is necessary to check their circumference.
Before starting to solder the pipes, it is important to remove the oxidized layer from all over the halo of the joint, since the oxide adversely affects the quality of the welds.
Before soldering it is important to insert the pipe into the fitting and make marks for the depth of its entrance, but taking into account that the pipe is inserted all the way to the stop. To avoid narrowing the pipe in the seam, you need to leave a gap of 1 mm.Back to table of contents
Heating temperature of the welder
If to compare with the butt soldering, where the parts are heated superficially and at low temperatures and for a long time, in order to avoid stress inside the material, in the socket welding of propylene the temperature of the apparatus is too high and it heats up faster. The choice of the heating temperature of the welded device is subject to several restrictions:
Soldering technology of polypropylene pipes.
- Melting of welded surfaces should be done quickly, pipes can lose their original appearance, and it will be difficult to combine them. This is the reason for the high temperature of the heating apparatus.
- If you overheat the welded device, the polypropylene elements may be subjected to thermal deformation.
- Teflon coating, which covers the working part of the apparatus, maintains excellent condition, if it is operated continuously at a temperature of 260 degrees, and if you use higher temperatures, the device gradually fails.
Taking into account all the nuances of socket welding, the optimum temperature for heating the working surface of the nozzles was set at 260 degrees, with deviations of plus / minus 10 degrees.
Such a heating mode can adversely affect the internal voltage at the joints. But this is almost completely compensated by the double wall of the pipeline system at the joints and by the maximum welding area.
Many models of devices for socket welding of pipes made of polypropylene are equipped with a temperature setting regulator. The thermostat is designed so that when setting the appropriate temperature, it corresponds to the temperature on the welded nozzles. The temperature of the heater is 15 degrees higher.
Most models of welded devices are outdated and do not have a knob of the regulator, and their temperature regime is set by the manufacturer immediately to 260 degrees. Given the working technology, according to the masters, this is correct, since the knob of the regulator is most likely set to increase popularity.Back to table of contents
How to choose a welding device?
As already known, for socket welding of polypropylene pipes the temperature of the nozzles is set to 260 degrees, but this should not be confused with the temperature of the heater of the device itself.
To create the required temperature on the working surface, nozzles are mounted on the welded device heater and bolted.
Manufacturers also manufacture nozzles and heating elements of various geometric shapes, but the principle is the same, since inside the aluminum heater a steel heating element is poured.
The power of the heater is approximately equal to 10 times the diameter of the welded polypropylene pipes. For example, a 500-watt heater is able to weld pipes and fittings with a cross section of 50 mm. accordingly, the 1200-cotton will weld parts with a diameter of 125 mm.
There are devices, manufacturers of which use cheap tubular heating elements, that is, two elements are poured into the aluminum of the heater, each of which has its own switch. In this case, each of the elements has enormous power for the nozzles, which is sufficient for heating the nozzles.
Double power can double the required power of the heater of the welding device and almost in vain overloads the thermostat of the power supply network. In this regard, it is better to keep the second heating element as a backup or use it to reduce the heating time of a cold soldering iron.Back to table of contents
Some nuances of welding polypropylene
When the welding device is plugged in, two indicators should light up on it, one of which shows the connection to the network and the other is a temperature indicator. The indicator is on until the welding heats up, it will take about 10 minutes. As soon as the indicator goes out, it means that the device has reached the maximum temperature.
But it is important to take into account that when you first turn on the device requires maximum energy, and because of this, the nozzles can have a temperature of about 320 degrees, which can lead to a distortion of polypropylene during welding. As is known, the optimum temperature should not exceed 260 degrees, and in order to achieve such a temperature, it is necessary to wait for the indicator to turn on again, turn it on and off. And only after that you can, without fear to start work.
To weld a polypropylene pipe, it must be placed in a hole on one side of the nozzle, and the fitting is installed on the projecting part on the opposite side. Taking into account the cross-section of welded pipes, it is necessary to change the time required for heating, joining and cooling of the welded place.