In winter, very cold temperatures can occur.Even when the thermometer drops below 0º, the water in the pipes begins to freeze. If there are open areas of the water supply system, sewers that are not protected from freezing, the functioning of such important life support systems becomes impossible.
To ensure the normal operation of water communications, which are located on the street or in unheated premises, special electrical wires are used. As carried heated pipes, will be considered below.
Application area
Electric heated pipes allows you to maintain optimal insidethe temperature at which water does not freeze. Today, to create such a system, various wires are used. They may differ significantly externally, functionally. Depending on the type of wire, they can wind the pipes or wind the heating wire directly inside.
The systems presented are mounted on variouspipelines. It can be household and industrial communications. The pipes are insulated not only outside the buildings, but also inside the basements, attics, and other unheated premises. Regardless of the location of communications, electrical cables are used for heating. Pipes can be buried deep in the earth or pass on the surface.
In addition to heating the water supply, the presented systems are used to ensure the normal functioning of the sewage system, various tanks, drainage, as well as fire hydrants.
Functions
Heated water pipe from freezing produced by different varietiessystems. They all perform identical functions. The cable, regardless of the type and method of installation, keeps the contents inside the communications in a liquid state.
Also, the wire prevents the formation of plugs fromice, preventing the lack of movement of contents through the system. Water can move freely through the pipes. At the same time its speed of movement increases. Of the liquids that move inside the pipes, no solid fractions are formed. No condensation forms on the pipe surface.
Owners of a private home may not alwaysstay in your country cottage in winter. If they come here periodically, you will need to protect communications from freezing. Otherwise they will not be able to operate the water supply system, sewage system. Ice appears from the low temperatures inside the pipes. In some cases, a break in communications is possible. When it gets warmer, water will seep from the pipes. Therefore, it is important to correctly mount the cable for heating.
Varieties
For heating pipes used various systems of electrical wires. They can be divided into two large groups. It is resistive and self-regulating heating cable.
Resistive wire is stabletemperature, which does not change along the entire length of the wire. This cable consists of a metal conductor through which current is applied. It heats the conductor, all the sheaths of the wire. It is a robust system that can vary in insulation class and capacity. Depending on the features of the outer sheath, the presented cable can be wound directly into the pipe or wound around the communications.
Self-regulating wire consists of two wiresbetween which there is a polymer matrix of semiconductor material. Electricity flows through the system to a greater extent if it becomes colder in the environment. Heating the wire will be stronger in this case. When it gets warmer in the environment, the matrix reduces the electricity supply through the system. The wire will heat up less.
Resistive Wire Features
Heated plastic pipes and metal communications is possible withusing a resistive cable system. This wire is heated to a certain temperature. In order to be able to adjust the heating level, a thermostat is necessarily added to the system.
Резистивный провод состоит, как уже было сказано above, from the core and protective shells. For this, manufacturers use different materials. Depending on the selected protective sheaths, the cable receives special performance characteristics. If the outer layer is additionally reinforced and made of food-grade plastic, the wire can be installed directly into the water pipe.
However, more often the wire is pulled from the outsidecommunications When using the presented wire, it is important to calculate the required power. Also, the density of laying the wire turns plays an important role in creating high-quality heating.
Disadvantages of resistive wire
Today, many manufacturers produce cable for heating pipes which is characterized by a mass of characteristics. However, there are certain disadvantages that are inherent in almost all resistive wires.
The presented category of heating systems asit has already been said above, it is distinguished by the same temperature along the entire length. This means that the system along which the wire is laid must also differ in identical temperature along the entire length. If this is not the case, the cable will overheat in some areas. This significantly reduces its service life.
It is also forbidden to cross the wire, which greatly complicates its installation on hydrants, cranes. If you put the cable coils close to each other, then the system may also overheat.
Also a disadvantage is the need to use a thermostat. This increases the cost of installing pipe heating.
Features self-regulating wire
Self regulating heating tape differs in a number of features. This system does not require a thermostat. The built-in matrix itself determines to which temperature the wire is currently to be heated.
Причем следует отметить, что саморегулирующийся The cable can be cut, unlike the resistive wire. It consists of separate blocks. Therefore, in different parts of the tape the temperature may be different. This does not reduce the life of the wire. If there is an extra piece of tape left, it can simply be cut off. Resistive cable will have to be laid completely.
Depending on the braid, self-regulatingwire can also lead directly into the water pipe. In this case, less cable is required. Its efficiency will be higher, as the water inside the system will heat up directly. In this case, less energy is expended.
Wire cost
Pipe heating system today performed using both categorieswires. Despite the fact that the resistive wire has a lot of disadvantages, compared with self-regulating varieties, it is installed on various communications of private and industrial facilities. This is due to the lower cost of such a system. The disadvantage of self-regulating wire is its relatively high cost.
However, it should be noted that the total costresistive wire systems with a thermostat range from 1,800 rubles. for 1 m cable. The price includes the cost of the thermostat. It costs about 800-1500 rubles. Without a control system to install the wire will not work.
Саморегулирующийся провод стоит порядка 500 руб.for 1 m. If you need to purchase such a system in bulk, the price can be reduced to 250 rubles. for 1 m. In this case, the installation will be much cheaper than when buying a resistive wire.
The advantages of self-regulating wire
Self-regulating heating cable different advantages compared toit with resistive systems. The main feature of it is the lack of a thermostat. The durability and quality of heating when using self-regulating wires will be higher.
The system is protected from overheating.It adapts to environmental conditions. At the same time the cable consumes the optimal amount of electricity. Owners of a resistive heating system should independently set the heating level of the wire. In this case, electricity under equal conditions will be spent more.
Саморегулирующийся провод прост в монтаже.It can be crossed, providing heating of hydrants and cranes. If necessary, the system is cut into sections of up to 15 cm. This allows you to mount exactly as much wire as is necessary for this object. The system is connected to the network using a conventional electrical plug.
System power
Heated water pipe производится кабелем определенной мощности.In order for the system to work efficiently, it is necessary to take into account to which point the thermometer may fall in winter. Also when choosing the power of the system, it is important to pay attention to the location of the object, its length. The diameter of the pipe affects the choice of wire power. When calculating, it is necessary to take into account the material from which the pipe is made, as well as the thickness of the insulation above it.
There is a certain formula that is used by experts to calculate the power of the wire. She looks like this:
M = (2 x 3.14 x Tt x D x (Tj - Tn) / Dk x (Dt / Dn) x 1.3, where:
- TT is the thermal conductivity of the insulation. For calculations, the most commonly used indicator is 0.04.
- D is the length of the pipe.
- Tj - the temperature of the fluid in the pipe.
- Tn - the minimum temperature outside.
- Dt is the outer diameter of the pipe with heat insulation.
- DN - outer diameter without heat insulation.
- DK - cable length.
To find the indicator Dk, it is necessary to take into account not only the length of the object, but also all the plugs, hydrants and other elements of the system.
Calculation example
To find the power wires needed for heated pipes need to make a calculation.To do this, consider a number of system parameters. For example, the owner of a private house has a water pipe that must be insulated. Its diameter without insulation is 32 mm. The length of the object is 45 m. It is known that in this area the temperature in winter does not fall below -35ºС. It is planned to mount a heat insulation layer on the pipe, which will be 25 mm.
To choose the optimal system, you need to calculate the above formula. It will look like this:
M = 3.14 x 2 x 45 x 0.04 x (5 - (-35)) / 73 (82/32) x 1.3.
M = 625 watts.
If we calculate the power of the system for each running meter, we get the result of 14 W / m.
On sale are various wires. Their power ranges from 10 to 40 W / m. Depending on the operating conditions choose a particular variety.
If the wire is mounted outside the pipe,the minimum power for a pipe with a diameter of 32 mm is 15 W / m. With the increase in the size of the cross-section of communications, this figure increases. If the pipe has a diameter of 50 mm, the recommended power reaches 24 W / m, and for 150 mm - 40 W / m.
If the wire is installed inside the pipe, low power systems can be used. For communications with a cross section of up to 80 mm, wires with a rating of up to 13 W / m are suitable.
Mounting Features
To mount heated pipes, you must purchase the required power cableand lengths. If you plan to install a resistive version, a thermostat with a remote sensor must be purchased without fail. He will control the heat.
Также обязательно в систему монтируется УЗО.They are mounted in a special control cabinet mounted inside the house. Also purchased an additional aluminum tape for fastening wires, heat insulation on the pipe.
Wire installation
Before you install heated pipes, следует внимательно ознакомиться с инструкцией manufacturer. The wire can be mounted on the pipe in a spiral or pass a straight line. The choice depends on the features of communications. With the help of adhesive tape the cable is fixed on the surface. If you plan to install a wire inside the pipe, you will need to turn off the water supply. At the appropriate point, the cable is inserted into the system.
If necessary, a sensor from a thermostat is installed on the surface of the pipe. It is also fixed with scotch tape. Next, the system is covered with a layer of insulation.
Having considered the features of choice and installation heating pipes You can properly install an effective system on the desired object.
