Calculation method of electrical heat tracing, calculation method of electric heat tracing

1. Calculate the heat loss (related to the pipe diameter, thickness of the insulation material, maintenance temperature, and the minimum temperature of the environment).

2. What type of electric heating is suitable for the complexity of the length of the pipeline? (self-regulating or constant power, whether it can withstand the maximum temperature of pipeline medium, explosion-proof level, temperature group, etc.).

3. If there is no heating requirement, select the winding ratio so that the output power of the electric partner is slightly greater than the calculated heat loss. (The winding ratio can be understood as the number of roots per meter of the pipeline that needs to be accompanied).

4. Obtain the winding allowance of the valve bracket flange on the pipeline.

5. The length of the pipeline is multiplied by the winding ratio plus the winding allowance required by the valve bracket flange on the pipeline is the required length.

Remarks: 1. It is also necessary to consider the margin of the actual installation wiring of the power junction box, tail end and two-way or three-way junction box.

2. If the pipeline has not been installed according to the design, it is recommended to consider the possible changes in the actual pipeline length.

How to determine the power of the electric heat trace and the length of use.

1.Because the specific equipment requirements are different, the electric heat trace model used is not the same, so as long as the length and energy consumption are too general, the output power per meter given in the design document multiplied by the length is the energy consumption, and the power curve of the corresponding model is estimated simply by looking at the manufacturer's design document or referring to the manufacturer's sample.

2.The simplified formula for calculating pipe heat loss is q=2 vulk(tp-ta) ln(d2 d1).

Where: K is the thermal conductivity of the insulation layer, note that K is the value calculated according to the thermal conductivity equation, TP is the maintenance temperature, TA is the minimum temperature of the environment, D1 is the inner diameter of the insulation layer (outer diameter of the pipe), and D2 is the outer diameter of the insulation layer.

3.The manual of the electric heat tracing manufacturer will introduce the exposure temperature and temperature resistance temperature of different types of electric heat tracing, which can be checked against each other.

Of course, it still depends on the specific situation of the site, because the region, environment, and temperature requirements are different, so if the user decides not to, it is necessary for professional electric heating technicians to determine, and after calculation, the user will purchase the corresponding electric heat trace model for installation.

There are many factors Pipe diameter Insulation thickness If in doubt, 13xx82x1431 x represents 9 Shenyang Ruihuadian heat tracing.

Calculation method: 1. The heat generated by the current through the conductor is proportional to the quadratic of the current, proportional to the electric heat trace of the conductor, and proportional to the time of energizing. Joule's Law Mathematical Expression:

q=i^2;RT (for all circuits); For purely resistive circuits, it can be derived. q=w=pt;q=uit;q=(u^2/r)t

It is important to note that these two formulas only apply to purely resistive circuits, and not to non-purely resistive circuits.

2. In a series circuit, since the current through the conductor is equal, the energizing time is also equal, according to Joule's law, the heat generated by the current through the conductor is proportional to the resistance of the conductor. In parallel circuits, since the voltages at both ends of the conductors are equal, the energizing time is also equal, and according to Joule's law, the heat generated by the current passing through the conductor is inversely proportional to the resistance of the conductor.

3. Impure resistance circuit: how to measure the resistance of Q=i 2RT electric heat tracing:

1. In the actual use of electric heat tracing, the resistance of the electric heat trace needs to be measured before installation, so how to measure the electrical heat resistance. Temperature-controlled electric heat tracing insulation resistance detection, mainly to detect whether the electric heat tracing is damaged, as well as the wiring of wiring, terminal wire, belt and belt wiring may exist short circuit, leakage and other problems.

2. Insulation resistance detection is required in the following processes:

1) Preliminary inspection: As mentioned earlier, it is carried out before the installation of the electric heat tracing.

2) Acceptance test: before the installation of the electric heat tracing and accessories is completed and the insulation is completed.

3) Final test: This test is carried out before the insulation is completed and the system is energized.

3. When measuring the insulation resistance, use an insulation tester with a minimum voltage of DC500 V and a maximum test voltage of DC1000V, no matter how long the system is, and the insulation resistance should be at least 10 Mohm per heating circuit.

1) Electrical Heat Tracing with Protective Braids and Jackets: Measurements are taken between each electric heat tracing conductor and the protective braid, as well as between the protective braids and the grounding pipe.

2) Electrical heat tracing without braided sheath: Measurement is made between each power wire and the grounding pipe or thermally insulated grounding steel sleeve of the electrical heat tracing.

4. Precautions when measuring the insulation resistance of temperature control electric heat tracing.

When measuring insulation resistance, read from right to left, 0 on the right and 0 on the left. For example, the resistance value is stronger to the left ( ) and the worse the insulation is to the right (0). (The higher the insulation resistance measurement) is in m.

When the electric heat trace is installed in the usable area, it should be tightly bandaged with an end cap after being cut off.

The electric heat trace should have no outer skin damage at the tail end, and it is strictly forbidden to enter the water after it is cut off.

The longer the line, the more parallel resistance, the smaller the resistance, the greater the current, the longer the electric heat tracing, the greater the resistance, the greater the resistance, is not the structure of the heat tracing, not the series structure.

I don't understand what you mean, first of all, when the heat tracing is just started, the power is the maximum, the instantaneous current reaches the maximum, we call it the starting current, as the temperature of the heating heat increases, the power is gradually reduced, and the current is getting smaller and smaller The general starting current is the normal current If you haven't understood it, you can Ruihua electric heat tracing.

There are constant power and self-limiting heat tracing, and you calculate the heating cable.

There are a series of calculation formulas, mainly to calculate the power of the required electric heating through heat loss, so the following calculation formula is very important.

Calculation of heat consumption.

1+ 2=Qmcp(T2-T1)+KLQ (1) where - the heat consumption of the electric belt, W 1 - the heat consumption of the gas heating heat, W 2 - the heat dissipation of the heated pipe by the electric belt, w qm - the mass flow rate of the gas, kg s cp - the specific constant pressure heat capacity of the gas, j (kg·k) t2 - the terminal temperature of the gas, t1 - the temperature at the beginning of the gas, k - the compensation coefficient, generally take l - the length of the heated pipe by the electric belt, m

Q - the amount of heat dissipation per unit length of the heated pipe by the electric heat, w m

Ignoring the thermal resistance of the pipeline and the convective heat transfer between the gas and the inner surface of the pipeline, equation (2) is obtained.

where tf - the temperature of the gas in the pipe, ta - the temperature of the surrounding air, a - the thermal conductivity of the insulation material, w (m·k) d1 - the outer diameter of the pipe insulation layer, m d0 - the outer diameter of the pipe, m

The above calculation formula involves complex parameters such as local temperature, thermal conductivity of insulation materials, etc., and it is more prudent to find a professional electric heating manufacturer for design and selection.

Heat tracing calculations.

a.Calculation of heat consumption in electric heat.

1+ 2=Qmcp(T2-T1)+KLQ (1) where - the heat consumption of the electric belt, W 1 - the heat consumption of the gas heating heat, W 2 - the heat dissipation of the heated pipe by the electric belt, w qm - the mass flow rate of the gas, kg s cp - the specific constant pressure heat capacity of the gas, j (kg·k) t2 - the terminal temperature of the gas, t1 - the temperature at the beginning of the gas, k - the compensation coefficient, generally take l - the length of the heated pipe by the electric belt, m

Q - the amount of heat dissipation per unit length of the heated pipe by the electric heat, w m

Ignoring the thermal resistance of the pipeline and the convective heat transfer between the gas and the inner surface of the pipeline, equation (2) is obtained.

where tf - the temperature of the gas in the pipe, ta - the temperature of the surrounding air, a - the thermal conductivity of the insulation material, w (m·k) d1 - the outer diameter of the pipe insulation layer, m d0 - the outer diameter of the pipe, m

1 - surface heat transfer coefficient between the surface of the insulation layer and the surrounding air, w (m2

k) When only the gas and pipe temperatures are kept constant, only the heat dissipation per unit length of the pipe Q needs to be calculated. In this project, TF=5, TA=-34, D1=, D0=, =, 1=28W (m2

k), l = 80m, q=, =1404w according to equations (1) and (2).

b.Calculation of electric heat heater power.

where p - the power of the electric belt, w - the efficiency of the electric belt, take p = 1652w in this project.

c.Calculation of the pitch of the electric tropical winding.

How to calculate the secrecy!

Outer diameter DN40 1m 20-25W

Outer diameter DN50 1m 25-30W

Outer diameter DN80 1m 35-40W

Outer diameter DN100 1m 40-45W

The above refers to the heating load of outdoor pipelines!

What is an Electric Heat Tracing Cable?

In general, the calculation of the maximum energy consumption can be calculated by knowing its power;

The temperature resistance is related to the coating material used, and different materials have different heat resistance levels.