Heat tracing cable

After the heating cable is powered on (note that the tail core must not be connected), the current flows from one core through the conductive PTC material to the other core, forming a loop. Electricity heats up the conductive material, causing its resistance to increase. When the temperature of the core strip reaches a certain value, the resistance becomes so high that it almost blocks the current, and the temperature no longer rises. At the same time, the electric belt transfers heat to the heated system at a lower temperature. The power of an electric heating belt is mainly controlled by the heat transfer process, and the output power is automatically adjusted according to the temperature of the heated system, while traditional constant power heaters do not have this function.

Overview of tropical regions

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Currently, traditional steam or hot water heating is mostly used for heat tracing of process pipelines and tank containers in China. Electric heat tracing is a high-tech product that uses the energy of electric heat to supplement the heat lost by the heat tracing body in the process flow, thereby maintaining a reasonable process temperature of the flowing medium. Electric heat tracing is a uniform heat release along the length of a pipeline or over a large area of the tank volume, which is different from electric heat tracing where the heat load is highly concentrated at a single point or over a small area; Electric heating has a small temperature gradient and a long thermal stability time, making it suitable for long-term use. Its required heat (electric power) is much lower than that of electric heating. Electric heat tracing has the advantages of high thermal efficiency, energy conservation, simple design, convenient construction and installation, no pollution, long service life, and the ability to achieve remote control and automatic control. It is a technological development direction that replaces steam and hot water heat tracing, and is a key energy-saving project promoted by the country.

Principle of tropical zone

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Heat tracing cableAfter connecting the power supply (note that the tail core must not be connected), the current forms a loop by passing through a conductive PTC material from one core to another. Electricity heats up the conductive material, causing its resistance to increase. When the temperature of the core strip reaches a certain value, the resistance becomes so high that it almost blocks the current, and the temperature no longer rises. At the same time, the electric belt transfers heat to the heated system at a lower temperature. The power of an electric heating belt is mainly controlled by the heat transfer process, and the output power is automatically adjusted according to the temperature of the heated system, while traditional constant power heaters do not have this function.

The advantages of electric heat tracing

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Compared with steam (hot water), electric heat tracing has many advantages as follows:

(1) The electric heat tracing device is simple, produces uniform heat, has accurate temperature control, and can be remotely controlled to achieve automated management.

(2) Heat has explosion-proof, all-weather working performance, high reliability, and long service life.

(3) Electric heat tracing has no leakage, which is beneficial for environmental protection.

(4) Save steel: It does not require the one to two heat tracing pipelines required for steam tracing.

(5) Save insulation materials.

(6) Save water resources, unlike boilers that require a large amount of water every day.

(7) Electric heat tracing can also solve the problem that steam and hot water heat tracing are difficult to solve.

(8) Electric heat tracing design has a small workload, easy and simple construction, and low maintenance workload.

(9) High efficiency, can greatly reduce energy consumption.

A one-time investment or annual operating costs, electric heat tracing is more cost-effective than steam heat tracing; Some projects may require a slightly higher one-time investment in electric heat tracing than steam hot water heat tracing, but in terms of annual operating costs, the cost savings from operating electric heat tracing for 1-2 years can usually recoup the investment.

Benefit Analysis of Using Tropical Companions

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Self controlled temperature electric tracing is an energy-saving measure that adjusts the heat generation based on the temperature of the sensitive pipe wall (medium) in this province. The power consumption per meter of the widely used self-control heating wire is 15W. The total length of the pipeline is 1000m, and the hourly power consumption is 15KW. h. When the pipeline temperature reaches the maintenance temperature *, the heat generated by electric tracing will gradually decrease, and the output power will also decrease accordingly. Therefore, the power consumption of electric tracing is generally 60% of the rated power; The factory electricity price is calculated at 0.60 yuan/KW. h, and the operating day is 100 days (2400 hours). Therefore, the normal annual electricity consumption cost is: (15 × 2400) × 0.60 × 60%=12960 yuan. When used in conjunction with a temperature controller, the self controlled heating belt can not only accurately maintain the medium temperature of the pipeline or heating element, but also greatly reduce the operating cost.

The heat generation per unit length of a constant power electric heating belt is constant, and the longer the electric heating belt used, the greater the total power output. The universal constant power electric heating wire has a power consumption of 20W per meter. The total length of the pipeline is 1000m, and the hourly power consumption is 20KW. h. When the pipeline temperature reaches the maintenance temperature *, the output power enters stability, and the power consumption of electric tracing remains unchanged; The factory electricity price is calculated at 0.60 yuan/KW. h, and the operating day is 100 days (2400 hours). The normal annual electricity consumption cost is: (20 × 2400) × 0.60=28800 yuan. When the constant power electric heating belt is used in conjunction with the temperature controller, it can also accurately maintain the medium temperature of the pipeline or heating element.

Service life of electric heating belt

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Under proper maintenance, the service life of the electric heat tracing system is 8 years or longer.

Application scope of electric heat tracing products

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Electric heat tracing products can be widely used in industries such as petroleum, chemical, power, medicine, machinery, food, and ships for heat tracing insulation, antifreeze, and anti condensation of pipelines, pump bodies, valves, tanks, and tank volumes. They are an effective method for maintaining process temperature in infusion pipelines and storage medium tanks. Electric heat tracing is not only suitable for various places where steam heat tracing is used, but also can solve problems that steam heat tracing is difficult to solve, such as heat tracing for long-distance pipelines and narrow spaces; Equipment with irregular shapes (such as pumps) for heat tracing; No steam heat source or heat tracing for pipelines and equipment in remote areas; Heat tracing for plastic and non-metallic pipelines, etc.

Classification of commonly used electric heat tracing

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Common electric heat tracing can be divided into the following types for different pipelines (tanks):

1. Self limiting (self controlled temperature) electric heating belt, which has a higher resistance and lower power as the temperature increases. Due to its high starting current, the length of use generally does not exceed 100 meters. The electric heating belt can be cut freely, and regardless of its length, it can generate heat when connected to the rated voltage.

2. Parallel type electric heating belt, which uses two (or three) parallel insulated copper stranded wires as power busbars, PTC characteristic heating wires wrapped around the skeleton, and alternating connection of busbars every other heating node length to form a continuous parallel resistor. The length of this electric heating belt is about 10-800 meters.

3. Series type electric heating belt, which consists of three parallel insulated copper stranded wires with the same cross-sectional area and a certain length as the power bus and heating core wire. One end is reliably short circuited, and the other end is connected to a 380V (or designed voltage) power supply, forming a star shaped load. According to Joule's law: Q=0.24IRT, electrical energy is converted into thermal energy. The star shaped load continuously releases heat, forming a continuous and uniformly heated electric heating belt. According to the actual situation, the three-phase (single-phase) of the electric heating belt can be separated (split type) or integrated into one. The length of this electric heating belt should not be too short, usually around 500-2500 meters.

4. High temperature electric heating belt, made of glass fiber or other high-temperature resistant materials, with a temperature resistance of up to 300 ℃ and a length ranging from 1-50 meters (as it cannot be cut arbitrarily, it needs to be designed by a professional manufacturer).

5. Silicone rubber electric heating belt, this electric heating belt can be used for heating, tracing and insulation of industrial equipment or laboratory pipe boxes, tanks and tanks, oil drums (boxes) in humid and non explosive gas places. The length of the electric heating belt is 1-15 meters (as it cannot be cut arbitrarily, it needs to be designed by a professional manufacturer)

6. MI cable, this heating strip is composed of a metal wire core (heating element), a mineral magnesium oxide (insulation layer) tightly surrounding the wire core, and a metal tube (usually copper, steel, or stainless steel, etc.) that has been drawn multiple times. The continuous working temperature can reach 250-590 ℃, and the short-term working temperature can reach 1083 ℃, with a length of 18-680 meters (due to its inability to be cut arbitrarily, it needs to be designed by a professional manufacturer).

Selection of electric heating belt

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How to choose electric heat tracing belts in practical engineering should be analyzed on a case by case basis. It is not advisable to divide them according to oil field blocks. Both constant power electric heat tracing belts and temperature controlled electric heat tracing belts should be selected from a technical and economic perspective. It is recommended to refer to the following selection principles.

(1) In the oil and gas separation zone composed of gas separation buffer tanks and natural gas separators, the ground oil pipelines, oil and gas separation buffer tank discharge pipelines, natural gas separators, and liquid level gauges are relatively concentrated, and temperature control is also strict. Constant power electric tracing belts can be used, where the liquid level gauge uses single-phase constant power electric tracing belts, and others use three-phase constant power electric tracing belts. This can be uniformly controlled by a set of explosion-proof distribution boxes and temperature controllers, but the distribution boxes, junction boxes, and temperature controllers must meet explosion-proof requirements.

(2) The water supply tank and water supply pipeline are generally far away from the explosion-proof area, and the heat tracing element is not too concentrated. The temperature control requirements are not high, as long as the water temperature is maintained within a certain range, it can meet the design requirements. Therefore, if a self controlled temperature electric heating belt is used, electric heating accessories such as distribution boxes and temperature controllers can be eliminated.

(3) In areas with many valve bends, cross overlapping installation may occur, making it unsuitable to install constant power electric heating strips (with separate electric heating wire layers). It is easy to choose self controlled temperature electric heating strips.

(4) From the perspective of design and installation, constant power electric heat tracing belts are generally limited by the section length. If a section length cannot be found accurately during cutting, that part of the heat tracing belt will not work, which not only affects the heat tracing effect of the pipeline, but also causes waste; And the self controlled temperature electric heating strip can be cut freely, ensuring the integrity of the electric heating strip.

A simple testing method for temperature controlled heating cables

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According to the IEC1423 standard, the following simple testing methods are recommended to users:

1. Starting current (is) or starting current equipment: multimeter, power supply, socket (preferably with switch), temperature tester

Test steps:

(1) Take a 1-meter-long cable (with 3-4 centimeters as the wire end), seal one end of the cable with insulation tape, and strip one end of the wire to connect to a plug.

(2) Connect a multimeter in series online and set it to (A -) 10A.

(3) Connect the power and read the instantaneous maximum current value, which is the temperature of the cable in the air at that time.

2. Nominal power equipment: multimeter, power supply, socket (preferably with switch), temperature tester, stainless steel cup, insulation material

(1) Take a 1-meter-long cable (with 3-4 centimeters as the end) and connect it as above.

(2) Fill the water cup with water, wrap the cable around the cup and keep it insulated, so that the system temperature remains unchanged for 5 minutes after the cable is powered on.

(3) Connect the power supply, read the steady-state (i.e. current value remains unchanged) current value, record the temperature, and measure the power supply voltage.

(4) Calculated power: P=UI unit W/M

The above method is simple and easy to implement, but not precise and is for reference only. But under the same temperature and environmental conditions, it is possible to compare and contrast products such as electric heating belts from different manufacturers, with the same specifications and power.

3. Insulation resistance

Take a 3-meter-long cable and measure it with a DC, 2.5KV megohmmeter. Cables without metal braiding should be immersed in water during testing, and voltage should be applied between two conductors connected to water. The megohmmeter should be shaken evenly for 1 minute before reading. Insulation resistance not less than 500 Ω M

Heating method of electric heating cable

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1. The core material of self controlled temperature electric tracing, PTC semiconducting plastic, has a resistance value that increases correspondingly with the increase of temperature. However, when the temperature rises to a certain value (this temperature value is the threshold temperature, which can be adjusted according to needs), the resistance suddenly increases sharply, thereby blocking the current and stopping heating; When the temperature is below the threshold temperature, the resistance of PTC material automatically decreases to conduct current and continue heating. So as to maintain the system at a stable temperature value. The basic self regulating electric heating wire (heating cable) consists of PTC core tape and insulation layer. The flat strip made by uniformly and continuously extruding (or winding) PTC material on parallel metal wire cores (also known as busbars) is called PTC core strip. Wrap a layer of polyethylene polymer or polyvinyl chloride insulation around him. When the environment requires reinforcement or corrosion resistance, a woven layer or fluoropolymer coating can be added. When the two conductive busbars at one end of the core strip are connected to the power supply, the current flows laterally through the parallel PTC material layer on one busbar to the other busbar, forming a parallel circuit. A certain length of core tape has a certain resistance at a certain temperature and exhibits PTC characteristics. When current flows through the parallel PTC material layers, Joule heating is generated, causing the core strip to heat up. At the same time, the heat of the core strip is transferred to the low-temperature heated system through the cable insulation layer to compensate for the heat lost by the system to the environment.

2. The power output of a constant power electric heat tracing belt remains constant after being powered on, and does not change with changes in the external environment, insulation materials, or heat tracing materials. The output or stop of its power is usually controlled by a temperature sensor.

A: The resistance wires of the parallel constant power electric heating belt are connected in parallel, and its operation relies on the heating of the resistance wires to heat the pipeline.

Principle: Two parallel nickel copper stranded wires are wrapped in a fluoride insulation layer as a power bus, and nickel chromium alloy heating wires are wrapped around the inner insulation layer. The heating wires are welded at fixed intervals to form a continuous parallel resistor. When the power copper bus is energized, each parallel resistor heats up, forming a continuous heating belt that can be cut arbitrarily.

B: The series type constant power electric heating belt has a series connection of resistance wires, which generate heat to heat the pipeline during operation.

Principle: The series electric heating strip is composed of insulated copper stranded wire as the power bus, which is the heating core wire. A core wire with a certain internal resistance will generate Joule heat when passing through a current core wire (Joule Lenz law Q=0.24I \ \ S2 ^; Rt), Its size is proportional to the square of the current, the resistance of the core wire, and the passage time. Therefore, as the power on time continues, the series electric heating strip continuously emits heat, forming a continuous and uniformly heated electric heating strip. The core wire current and resistance of the series electric heat tracing belt are the same, so the entire electric heat tracing belt generates uniform heat at both ends, and its output power is constant and not affected by environmental temperature and pipeline temperature.

3. Mineral insulated heating cable is a special heating cable with metal as the outer sheath, electric heating material as the heating element, and magnesium oxide powder as the insulation. The heat generation of mineral insulated heating cables is related to the working voltage, the cross-section of the heating core, and the length of the cable.

Principle of self controlled temperature tracing cable

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The self controlled temperature electric heating scheme is mainly achieved through the self controlled temperature electric heating wire. The self controlled heating wire is composed of conductive plastic, 2 parallel busbars with insulation layer, metal shielding mesh, and anti-corrosion jacket. The conductive plastic made by special processing of plastic and conductive carbon particles is the heating core. When the temperature around the heating wire is low, the conductive plastic undergoes micro molecule contraction, and the carbon particles connect to form a circuit that allows current to pass through, and the heating wire begins to heat up; When the temperature is high, the conductive plastic produces micro molecule expansion, and the carbon particles gradually separate, causing circuit interruption, resistance increase, and the heating wire automatically reduces power output, resulting in a decrease in heat generation. When the surrounding temperature cools down, the plastic returns to a state of micro molecule contraction, and the carbon particles are connected to form an electrical circuit, causing the heating power of the heating wire to automatically increase. Due to the fact that the entire temperature control process is automatically adjusted by the material itself, the controlled temperature will not be too high or too low. Therefore, the good characteristics of electric heat tracing are similar to those of other heat tracing systems.

Constant power cable structure

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1.1 Internal structure of single-phase parallel constant power electric heating belt:

Two parallel insulated copper stranded wires are used as power busbars, and PTC characteristic heating wires are wrapped around the skeleton. They are alternately connected every other heating node length to form a continuous parallel resistor. Connect a single-phase 220V power supply to the busbar, and the parallel resistors generate heat.

1.2 Appearance of single-phase parallel constant power electric heating belt:

A - Core wire

B-Core wire insulation layer fluoroplastic

C - Skeleton layer

D - Heating wire

E - Fluoroplastic insulation sheath

F - Metal shielding mesh

G-outer sheath fluoroplastic

2.1 Internal structure of three-phase parallel constant power electric heating belt:

Three parallel insulated copper stranded wires are used as power busbars, which are alternately connected to the power busbars a-b-c-a-b-c every other heating node length, forming continuous parallel resistors in every three phases. The busbars are connected to a three-phase 380V power supply, and each parallel resistor heats up.

2.2 Three phase parallel three-phase electric heating belt structure

A - Core wire

B-Core wire insulation layer fluoroplastic

C - Skeleton layer compacts

D - Heating wire

E - Fluoroplastic insulation sheath

F - Metal shielding mesh

G-outer sheath fluoroplastic

3.1 Principle and appearance of series electric heating belt structure

Three parallel insulated copper stranded wires with the same cross-sectional area and a certain length are used as the power bus and heating core wire. One end is reliably short circuited, and the other end is connected to a 380V power supply, forming a star shaped load. According to Joule Lenz's law: Q=0.24IRT electrical energy is converted into thermal energy, and the star shaped load continuously releases heat, forming a continuous and uniformly heated electric heating belt. According to the actual situation, the three-phase (single-phase) of the electric heating belt can be separated (split type) or integrated into one.

1. Three constant power series electric heating belts 2. Two constant power series electric heating belts 3 Single constant power series electric heating belt

A-Core

B-Busbar insulation layer

C-outer sheath

D-metal shielding mesh

E-reinforced (protective) sheath

Performance characteristics of heat tracing cables

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The self controlled temperature tracing cable can automatically limit the working temperature of the cable during heating; The self controlled temperature tracing cable can automatically adjust its output power according to the temperature changes of the heated system without the need for external equipment; Cables can be cut short or extended within a certain range without changing their performance; Allow cross overlapping winding and laying without the worry of overheating and burning; The temperature of the heat tracing pipeline is uniform, will not overheat, and is safe and reliable; Save electricity; During intermittent operation, the temperature rise starts quickly; Low installation and operation costs; Easy installation, use, and maintenance; Easy to automate management; No environmental pollution; Long service life and other characteristics.

The heat generation per unit length of a constant power parallel electric heating belt is constant. The longer the electric heating belt used, the greater the total power output, and the pipeline maintains a high temperature. The electric heating belt can also be cut to any actual length on site. In addition, due to its flexibility, the electric heating belt can easily adhere to the surface of the pipeline. The outer metal shielding mesh of the electric heating belt can prevent static electricity and ensure safe grounding. It not only improves the overall strength of the electric heating belt, but also plays a role in heat transfer and dissipation.

Basic structure and classification of self controlled temperature cables

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According to the composition of polymer PTC materials, self controlled heating cables are divided into two types: low-temperature and high-temperature.

Common heating cables in the market include 65 ℃ temperature grade heating cables based on polyolefins and 110 ℃ and 150 ℃ heating cables based on fluorine-containing materials. The temperature level here is defined as the maximum ambient temperature at which the heating cable can be effectively applied. It can also be understood as the maximum ambient temperature at which a cable can be stably used for a long time and generate effective heating power output. If it exceeds the specified temperature level, on the one hand, due to the increase in resistance, the output power of the cable itself is very small, and the actual heating efficiency is very low. On the other hand, long-term over temperature use can degrade or attenuate cable performance such as PTC characteristics and heating power, which can reduce the service life and operational reliability of the cable. But it is also possible to be exposed to temperatures exceeding the temperature limit for a short period of time. Therefore, in addition to the above temperature levels, there is another temperature level for self controlled heating wires. For cables with a temperature rating of 65 ℃, the temperature rating is 85 ℃, for cables with a temperature rating of 110 ℃, it is 130 ℃, and for cables with a temperature rating of 150 ℃, it is 230 ℃. However, at this point, the effective output power of the cable is close to zero.

Due to a lack of relevant literature, many people have a wrong understanding of the temperature rating of self controlled heating cables, believing that it refers to the highest surface temperature of the heating cable. Therefore, there have been claims of polyolefin heating at temperatures of 45.65, 85, and 105 ℃. In fact, the output power of the cable is related to the ambient temperature, and the surface temperature of the cable is closely related to the ambient temperature and insulation state during testing. Therefore, using surface temperature to define the temperature level of self controlled heating cables is unscientific and inaccurate. We need to remember that for heating cables based on polyolefin, their maximum continuous operating temperature should not exceed 65 ℃.

The output power of a self controlled heating cable refers to the output power per unit length of cable at an ambient temperature of 10 degrees Celsius. Classified by heating power output, there are three types of self controlled temperature heating cables: high, medium, and low. Generally speaking, low-power heating cables have a heating power of less than 35 watts per meter; Heating cables with a power greater than 35 watts per meter but less than 70 watts per meter are considered medium power heating cables; High power heating cables are those that heat up to 65 watts per meter.

Universal heating cable: refers to a heating cable composed of copper wire, polymer PTC material, and a single-layer flame-retardant sheath. Mainly used for heating or tracing in general pipeline networks. Explosion proof enhanced heating cable: It is a composite layer of metal mesh on the outer layer of a universal cable, which can effectively eliminate static electricity and resist external mechanical impact. Mainly used in places with explosion-proof requirements.

Anti corrosion and explosion-proof enhanced type: This type of cable structure is composed of a layer of fluorine-containing material on the outer layer of the metal mesh of the explosion-proof enhanced heating cable. Heating cables with this structure can effectively prevent and resist static electricity, mechanical collisions, and various corrosive media. Mainly used in places with harsh environments or flammable and explosive materials. Classified by cable usage

Ordinary heating cable: This is a two core structure heating cable. Composed of two parallel metal wires coated with polymer PTC material and flame-retardant sheath material or metal mesh and fluorine material sheath. Due to the influence of conductor diameter and voltage drop along the length, the connection length of this cable generally does not exceed 200 meters.

Ultra long heating cable is a special structure of five or six core heating cable. In addition to the two parallel wires wrapped in polymer PTC material, 3-4 metal wires with insulating sheaths and metal armor are also laid in the same direction. Used for transmitting electrical energy. This special structure allows the longest continuous use length of the cable to exceed 1100 meters, making it suitable for heat tracing in oil and gas pipelines and underground oil fields.

Safe heating cable? This is a three core heating cable. In the cable, lay another monitoring wire along the length direction inside the flame-retardant sheath. Monitoring wires can promptly transmit information such as abnormal changes in output power, overcurrent conditions, and local damage along the line to the central control room, facilitating timely understanding of the heating situation along the line and ensuring the safe and reliable operation of the cable.

Low voltage type: refers to heating cables with a suitable voltage range between 12-36V. These types of cables generally have lower heating power and can be used continuously for a length of no more than 10 meters. Strictly follow the voltage requirements when using, otherwise it may cause accidents such as cable fire. The application scope mainly includes civilian health products and heated seats for vehicles and ships.

Medium voltage type: refers to heating cables suitable for voltages between 100-660V. The self controlled heating cables we generally refer to are of this type. In practical applications, 120 and 250V cables are interchangeable, but the maximum continuous length of 120V heating cables is usually half of 240V. The continuous application length of such cables usually does not exceed 200 meters.

High voltage cable: refers to a heating cable suitable for voltages between 380-650V. They are mainly 5-6 core heating cables mentioned earlier. The continuous application length is usually greater than 500 meters.

System Composition

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Any model specification, such as self limiting temperature electric heating belt, constant power electric heating belt, etc

Explosion proof power junction box: used to protect the safe wiring of electric heating belts. The quality of the connectors is related to the safe use and service life of the electric heating system. The commonly used model is FDZ

Explosion proof intermediate junction box: facilitates the connection of electric heating belts on complex pipeline systems. On the premise of ensuring that the maximum usage length is not exceeded, it can also be used as a power junction box. The common models are FIH and FTH, etc

Tail end junction box: One section of the self limiting temperature electric heating belt can be connected to the power supply, and the other section can be sealed with a tail end junction box or heat shrinkable tubing. It is strictly forbidden to connect the two sections of the electric heating belt or connect two parallel busbars FZH

Explosion proof temperature controller: using thermocouple temperature control probe to sense the temperature of the heat tracing belt, manually precise temperature control, PTC self limiting electric heating belt can be installed without installation, using heating wire for heating such as constant power electric heating must use a temperature controller to limit the temperature, universal model BJW

Aluminum foil tape: used to expand the heating area of the electric heat tracing belt, increase the heat gathering and insulation range, and improve the heat tracing efficiency

Thermal tape: used to fix the system, usually by sticking the electric heating belt to the heat tracing pipeline or related equipment, and also using stainless steel zip ties for fixing

Warning label: After construction is completed, stick it on the outer surface of the heat tracing pipeline as a symbol and power on warning [1]

Installation and construction of heat tracing cables

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Installation construction is the key to using heat tracing cables well. Before installation, carefully read and have a professional electrician responsible. Installation and construction are generally divided into:

1. Confirm whether the installation conditions are met; 2. Install heat tracing cables and terminals; 3. Install the power box; 4. Measure insulation resistance; 5. Connect the power supply and switch; 6. Power on experiment; 7. Make electric heat tracing markings; 8. Repeat steps 4 and 6; 9. Perform insulation and waterproofing; 10. Acceptance.

The installation of heat tracing cables should be carried out after the completion of the main project, that is, no welding, lifting or other operations should be carried out above the installation site of the heat tracing cable to avoid damage caused by smashing. It should be confirmed that the pipes or equipment that require heat tracing have been leak tested, cleaned, and the burrs, sharp or edge like protrusions on their surfaces have been polished flat.

The heat tracing cable should be distributed according to the length of the pipeline, and the material on one side should cool down and condense at the location without heat tracing cable. The length of the heat tracing cable should be longer than that of the heat tracing pipeline. During installation, the length of the heat tracing cable used (including the total length of each parallel branch) should be verified to ensure that it does not exceed the design length or the maximum allowable usage length. When laying, the heat tracing cable should be placed flat and tightly against the surface of the pipeline or container as much as possible. It should be fixed with polyester tape or aluminum foil tape, and it is strictly prohibited to tie it with thin wires. The spacing between the tapes should be less than 30mm. In case of sharp protrusions such as flanges and valves, attention should be paid to protection. When installed on a horizontal pipeline, it can be laid at a 45 degree angle below the pipeline. When installing the heat tracing cable, it is allowed to cross and overlap multiple times, but twisting should be minimized as much as possible. To enhance the heat tracing effect, a layer of aluminum foil tape can be pasted on the outside of the heat tracing cable. When installing on the container, the heat tracing cable should be wrapped around the middle and lower parts of the container, usually not exceeding 2/3. After installation, insulation testing should be conducted on each heat tracing cable. The resistance between the core of the heat tracing cable and the pipeline or container should not be less than 20M Ω. Otherwise, the cause should be identified before connecting the power supply and insulation. This test should be conducted multiple times. The test results should be recorded for future reference.

Firstly, check that the cross-section of each power line should be slightly larger than the core cross-section of the heat tracing cable. The total power line should be able to withstand the total current of the heat tracing cable at low ambient temperatures. Each heat tracing cable should have its own switch, fuse, or single pole circuit breaker. When stripping the core of the heat tracing cable, it is necessary to avoid cutting the strands and reducing the cross-section, which may cause overload.

1. Connection between heat tracing cable and power box: In flammable and explosive environments, a matching explosion-proof power junction box must be used. In general, the heat tracing cable can be directly connected to the knife switch, or the wire can be twisted or welded and sealed with quick drying silicone and heat shrink tubing. The twisted joint should not be less than 30mm, and the welded joint should not be less than 10mm.

2. Branching of heat tracing cables: In flammable and explosive environments, a matching explosion-proof straight junction box must be used, and in general, twisting or welding can also be used.

3. Extension of heat tracing cables: In flammable and explosive environments, a matching explosion-proof straight junction box must be used, and in general, twisting or welding can also be used. Please be careful not to exceed the maximum usable length when extending.

4. Terminal: In flammable and explosive environments, a matching terminal sealing box must be used. In general, quick silicone and heat shrink tubing sealing can also be used. Under no circumstances should the tail core be connected.

5. Power junction box: T-shaped, straight type junction box, the terminals can be fastened to the pipeline with clamps or nylon ties, and the waterproof rubber pad inside the box must not be missed. The wiring inside the box should be waterproofed with quick drying silicone. When doing insulation, the junction box should be placed inside the insulation layer, but corresponding marks must be left at the insulation layer.

The insulation layer and waterproof layer are important components of the heat tracing cable system, and must be installed strictly according to the design requirements, especially outdoors. Once rainwater enters the layer, the insulation capacity will be greatly reduced. If the sheath is damaged, it may cause electrical breakdown, sparks or hidden fires. Therefore, it is necessary to strengthen on-site management to prevent construction personnel from accidentally damaging the heat tracing cable. After passing the insulation test, the insulation layer and waterproof layer should be installed as soon as possible. During installation, the metal sheet should be prevented from cutting the heat tracing cable sheath, and the screws fixing the iron sheet should not be too long or punctured on one side

Installation of tropical control alarm box

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According to relevant specifications and combined with the actual situation of the project, the positioning principles of the electric tracing control alarm box have been explored and formulated: ① Based on the location of the distribution room; ② Does not affect the installation of other electrical equipment; ③ The installed wall is a solid wall, and brackets should be added to ceramic or hollow brick walls; ④ The principle of high and low positions should be easy to observe and maintain. Based on the above positioning principles and the layout of the electric tracing system pipeline, a two-wire tracing cable control alarm box was adopted. Place them in the distribution rooms or duty rooms on both sides of the platform and the distribution room on the concourse level, and supply 220V voltage to the control box from the distribution box in the distribution room. Each heating cable control box is connected with 2 double conducting heating cables to heat the fire water supply pipes under the platform slab and in the ceiling of the station hall. The heat tracing control alarm box should be installed strictly according to the design requirements,

The installation height and vertical error of the box should be controlled within the allowable range of the specifications. The wiring inside the box should be neat and beautiful, with a reasonable direction, tied into bundles, and properly fixed. The connection head between wires and electrical appliances must comply with the specifications, that is, multi strand wires should be tinned after crimping, and single strand wires should be wound in a spiral steering wheel. When using bolt tops, double wire diameters should be inserted, and the length of the exposed conductor on the insulation edge of the wire end should not exceed 3 mm. Open type terminal blocks should not be used for wires with a cross-sectional area of 25 m ² or more. The movable contact end of the control appliance must be the load end. Each distribution branch and control circuit should be clearly marked in a dedicated nameplate box.

The precautions for using electric heating belts are as follows

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1. Electric heating belts must not be twisted, repeatedly bent, damaged outer sheaths, or insulation damaged during storage, handling, installation, and use.

2. During installation, avoid areas such as ditches, pits, and corners where flammable and explosive media may accumulate.

3. When selecting an electric heating belt, pay attention to its explosion-proof temperature group, which should not exceed 75% of the flash point or self ignition temperature of the flammable medium.

4. Do not bend or drag the electric heating belt over long distances on the ground.

5. The installation of electric heating belts must be carried out after the completion of the installation of the medium pipeline system and after passing the water pressure or air tightness test. The construction of the insulation layer must be carried out after the installation and commissioning of the electric heating belt are completed and the power transmission is normal.

6. When installing electric heating belts, sharp edges or corners should be polished smooth or covered with aluminum tape to prevent damage to the outer insulation layer.

7. The minimum bending radius during the installation of electric heating belts should generally not be less than 5 times their thickness.

8. When installing the electric heating belt, it should be tightly attached to the pipeline, and aluminum tape should be used as much as possible to stick it. The oil and moisture in the path should be cleaned up, and every 0 5～0. 8 m ， Use heat-resistant tape to fix the electric heating belt radially.

9. When installing accessories for electric heating belts, a certain margin should be left for maintenance purposes. For PTC parallel electric heating belts, they are composed of many parallel heating sections, so there are several tens of centimeters of cold ends at each end. Installation should start from the heating area, and the heating elements (especially parallel heating wires) at both ends should be shortened as much as possible, strictly prohibited from being exposed, and strictly prohibited from coming into contact with external woven nets or pipelines.

10. Except for the self controlled temperature electric heating belt, other specifications of electric heating belts are not allowed to cross or overlap during installation.

11. When wiring, the heating belt and accessories should be connected correctly and reliably to prevent short circuits. At the same time, the woven mesh should be connected to the ground (the grounding resistance should be less than 4.8).

12. After installation, insulation testing should be carried out using a 500V or 1000V megohmmeter. The insulation resistance between the core of the heating wire and the braided mesh or metal pipe should not be less than 2M Ω.

13. If steam blowing is required for the heat tracing pipeline, it must be carried out 2 hours after the power outage, and the temperature of the sweeping line should not exceed 205 ℃ for a long time.

14. When installing frost, it is necessary to follow the relevant provisions of the "Electrical Safety Regulations for Explosive Hazardous Areas" and the "Regulations on Electrical Equipment Installation Engineering and Acceptance" issued by the state.

Precautions for installing heat tracing tape

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1) All heat tracing cables must undergo circuit continuity and insulation performance tests, and those that do not comply with regulations cannot be used.

2) Electrical and control equipment must undergo visual inspection. If there is deformation, cracking, incomplete components that cannot be repaired, they cannot be used.

3) Before installation, the pipeline number, pipeline specifications, process conditions, and tracing cable parameters should be checked one by one according to the electric tracing system diagram

The specifications and models of electrical equipment and control equipment must be confirmed to be correct before installation can proceed.

4) Products without product markings, or with unclear markings that cannot be recognized, cannot be installed.

5) Before installing the electric heat tracing system, all the heat tracing pipelines must be constructed and checked for compliance through a water pressure test (or/and an air tightness test)

Ge.

1) When installing the heat tracing cable, do not drag it on the ground to avoid being damaged by sharp objects. Do not come into contact with high-temperature objects to prevent welding

Slag splashes onto the heating cable.

2) The heat tracing cable has good flexibility, but it is not allowed to be bent hard. When bending is required, the bending radius should not be less than 6 times the thickness of the heat tracing cable.

3) It is strictly prohibited to hit the heating cable with heavy objects. If the heating cable is hit, it should undergo electrical testing again and can only be used after passing the test.

4) The heat tracing cable should be tightly attached and fixed to the heat tracing pipeline (or equipment) to improve the heat tracing efficiency. When fixing the heat tracing cable, use specialized

Use nylon zip ties and strictly prohibit tying with metal wires.

5) A layer of aluminum tape should be applied between the outer wall of non-metallic pipelines and the heat tracing cable to increase the contact heat transfer area.

It is strictly prohibited to mix steam tracing and electric tracing together. When installing the heating strip, the insulation layer must not be damaged, and it should be tightly attached to the heated object to improve thermal efficiency. If the heat tracing element is a non-metallic body, use adhesive tape to increase the contact heat transfer area and fix it with nylon zip ties. It is strictly prohibited to tie it with metal wires. The medium at the flange is prone to leakage, so when winding the electric heating belt, it should be avoided directly below it. One end of the electric heating belt is connected to the power supply, and the other end of the wire core must not be short circuited or in contact with conductive substances and cut into a "V" shape. It must be tightly sealed with a matching head; Waterproof and explosion-proof occasions should have matching explosion-proof junction boxes and terminal blocks. After wiring, silicone rubber sealing should be applied (the shielding layer must be peeled off by 10cm at the terminal of the electric heating belt using a shielding layer to prevent short circuits); During installation, the insulation of each heat tracing point should be measured one by one, and the shielding layer must be grounded. The insulation resistance value should be small and can be less than 20M Ω (1000VDC). Bipolar power-off and leakage protection circuit breakers should be selected according to the voltage, current and other parameters of each electric heat tracing circuit. When steam cleaning and pipeline descaling are required, attention should be paid to cleaning first before installing the electric heating belt. If annual routine line cleaning and maintenance are needed, the installation should be designed and installed according to special circumstances

Knowledge to be mastered before using the tropical belt

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1. Before construction, it is necessary to understand the structure, performance, and installation requirements of the electric heating strip used.

2. The installation, commissioning, and operation of electric heating belts must comply with relevant provisions such as GB50254-96 "Code for Construction and Acceptance of Electrical Installations in Explosive and Fire Hazardous Environments" and GB50257-96 "Code for Construction and Acceptance of Low Voltage Electrical Appliances" issued by the state.

3. There is a minimum bending radius requirement for the installation and laying of various electric heat tracing belts, and excessive bending may damage the electric heat tracing belt.

4. The electric heat tracing strip laid parallel to the pipeline is generally installed below the pipeline and is at a 45 degree angle to the horizontal axis of the pipeline cross-section. Angle, if two electric heat tracing belts are used, they should be symmetrically laid.

5. When installing on the container, the electric heat tracing tape should be wrapped around the lower part of the container, usually not exceeding 2/3 of the container height, usually 1/3.

6. The electric tracing of non-metallic pipelines should be carried out by sandwiching a metal sheet (aluminum foil) between the outer wall of the pipeline and the electric tracing strip to improve the tracing effect.

7. The installation of electric heat tracing belts should fully consider the possibility of dismantling pipeline accessories and equipment to ensure that the electric heat tracing belts themselves are not damaged.

8. When installing accessories, it is required that the rubber rings, washers, fasteners, etc. are complete, installed correctly, and tightened to prevent loosening or water ingress into the box.

9. The insulation material outside the electric heating belt must be dry and ensure the quality and thickness of the material.

10. In humid and corrosive environments, reinforced or marine electric heat tracing belts must be used.

11. After the installation of insulation materials, a waterproof layer must be immediately wrapped to prevent rain and moisture.

12. When installing the electric heating strip, it is necessary to use a tail box and it is strictly prohibited to connect the tail core wire to cause a short circuit.

The maximum installation length of the 13 electric heat tracing belts should be less than 50 meters.

14. When laying horizontal pipelines in parallel, it is necessary to ensure that the electric heat tracing strip is tightly attached to the bottom of the pipeline, so as to more effectively transfer heat and reduce heat loss during operation.

15. At the same time, it should be noted that the anti freezing sensor should be installed at the upper part of the pipeline (i.e. in the opposite direction of the electric heating belt); The anti freezing sensor cannot be directly in contact with the electric heat tracing belt, so it cannot accurately detect the actual temperature of the pipeline.

16. When using other laying methods, attention should also be paid to the installation position of the antifreeze sensor, and it is best to place it at the low temperature point of the pipeline.

17. During the construction process, attention should be paid to checking the surface of the electric heating strip for scratches, cracks, etc. Once found, it should be replaced immediately.

18. In addition to installing smart meters to control the operation of the electric heat tracing belt, if the electric heat tracing belt is used alone for antifreeze, a leakage protection device must be installed at the power input end, and ordinary three terminal plugs cannot be directly used. The grounding protection wire should be reliably connected to the pipeline where the electric heating strip is laid. In this way, once there is a leakage phenomenon in the electric heating belt, the leakage protection device can reliably cut off the power supply to ensure safety.

Analysis and maintenance of self limiting electric heat tracing faults

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Routine inspection should be carried out before using the pipeline constant temperature system. If any damage is found to the electric heating belt, accessories, insulation layer or waterproof layer, it should be replaced and repaired immediately. The shaking table test can generally be conducted at the end of the line, and all repair details should be recorded on the repair record sheet.

Possible causes of fault signs and correction methods

Circuit breaker tripping:

1. Low temperature power transmission trip of heating system

2. Short circuit tripping of the circuit

3. The contact or middle of the electric heating belt burns out and trips

4. Multiple forced power transmission trips occurred, leading to combustion accidents. 1) The selection of the circuit breaker was too small, and the electric heating belt was used beyond its length, causing overload tripping. The maximum length of use is limited by the size of the product's conductive wire core cross-section, nominal power, the ambient temperature during start-up, or the temperature of the heat tracing system.

2) ① Short circuit caused by twisting the two wires at the end, ② Poor insulation of the contact or damage to the middle insulation layer due to installation. If a short circuit occurs midway during normal use, it is generally caused by the following reasons:

a. The insulation layer at the beginning and end shrinks, exposing the conductive part

b. Use absorbent insulating tape

c. There is a risk of damage to the insulation layer of the product, such as due to the use of rigid (iron wire) ties, drilling holes with electric drills, or the addition of insulation layer at the contact points without waterproofing during installation. These situations often result in incorrect use, leading to short circuits when conditions a, b, and c are wet.

3) The circuit is not equipped with leakage protection, overcurrent protection function control device, or if one or both of the protections fail, or if the electric heating belt is not grounded or shielded, forming a control circuit, when the above situation 1.2 occurs, tripping and multiple power transmissions will result in a burning accident, and the ultimate result is the burning of the electric heating belt.

4) Wrong selection of electric heating belt:

① Choose unshielded electric heating belt.

② If specialized products are not selected, such as products soaked in cold water, and parameters are selected according to conventional design, there may be a risk of two protections losing control and burning out during overload. 1) Preliminary thermal or electrical design shall be carried out according to the design book, and installation or correction shall be carried out according to the accident causes specified in the installation book or precautions;

2) Any circuit must be equipped with leakage protection and overcurrent protection.

3) The product must be of shielded or shielded reinforced type, and the product and controller should form an excellent control circuit.

4) Unshielded products should be considered semi-finished products and require additional safety measures. Otherwise, there may be safety hazards and it is considered illegal use.

5) After the circuit trips due to a drum, the explosion-proof area must not be subjected to secondary strong power transmission, otherwise although there is overcurrent protection, serious accidents such as burning may occur when the hidden danger or cause is unknown.

6) It is recommended to choose special series products in explosion-proof areas because these products are made of completely non combustible materials.

The system's heat generation tends to zero or lower. 1) The power supply voltage tends to zero or lower;

2) Some accessories are not connected or the electric heating belt is cut off;

3) Some accessories have improper connections;

4) Thermostat incorrectly calibrated to the closed state;

5) The pipeline is in a high temperature state, and the electric heating belt has been damaged;

6) The electric heating belt has been damaged due to exposure to excessively high temperatures;

1) Replace the damp insulation layer with a dry one and add a waterproof cover;

2) Use two-way connections to supplement the missing heating strip, but the total length of the line cannot exceed the limit;

3) Re calibrate the temperature controller;

4) Recheck the design parameters and make necessary adjustments;

The system generates normal heat, but the pipeline temperature is lower than the design value

1) The insulation layer has been affected by moisture;

2) Insufficient usage or improper selection of electric heating belts;

3) The constant temperature controller is not calibrated correctly;

4) The parameters used in the calculation of heat loss are inconsistent before and after; 1) Replace the damp insulation layer with a dry one and add a waterproof cover;

2) Use two-way connections to supplement the missing heating strip, but the total length of the line cannot exceed the limit;

3) Re calibrate the temperature controller;

4) Recheck the design parameters and make necessary adjustments

Adjustment;

Electric heating belt not hot or uneven heating and cooling

1) Beyond the expiration date, this situation generally gradually weakens;

2) A. Not insulated

b. The insulation layer is too thin or uneven in thickness

c. The insulation layer has not been waterproofed, and on rainy and snowy days, the insulation layer is soaked in water, causing the electric heating belt to remain in a low temperature or humid state for a long time and work at a high output power, which is not energy-saving and has uneven attenuation rates;

3) Poor quality of electric heating belt

1) Select electric heating belts from various manufacturers that have been tested and proven to be correct, and are labeled with nameplates, technical indicators, and manufacturing dates;

2) Strictly follow the product instructions for installation;

3) A waterproof layer should be installed along the entire insulation layer to ensure that the electric heating belt operates in a dry state;

4) Choose specialty products and identify the brand.

There is a large gap between the initial use effect and design effect of the electric heating belt

1) Incorrect product selection or low selection of technical parameters.

2) The usage conditions do not match the design selection criteria.

3) Fake and inferior (low, medium, and high temperature products are difficult to distinguish on the outside) products are caused by sellers deceiving users.

1) Strictly follow this "guide" for preliminary design and product selection;

2) At present, there are only 1-2 domestic manufacturers that can meet the technical indicators of their products, and only Wuhu Kehua is a special PTC manufacturer. Choose specialty products, identify brands, and select products.

Technical indicators:

1. Standard color: Red

2. Temperature range: maximum working temperature of 130 ± 5 ℃; The maximum exposure temperature is 150 ℃; Maximum temperature tolerance: Modified polyolefin 105 ℃, flame retardant polyolefin 105 ℃, fluorinated polyolefin 180 ℃, perfluorinated material 205 ℃

3. Construction temperature: Low -40 ℃

4. Thermal stability: After cycling back and forth 300 times between 10 ℃ and 149 ℃, the cable's heat generation remains above 90%.

5. Bending radius: 38.5mm at -20 ℃; 49.0mm at -30 ℃

6. Insulation resistance: When the cable length is 100m and the constant temperature water is 75 ℃; The minimum insulation resistance for testing is 20M Ω, with shielding or explosion-proof protection type. At room temperature of 20 ℃, shake test with 2500VDC between the shielding layer and the conductive wire core for 1 minute, and the minimum insulation resistance is 1200M Ω.

After the installation of the entire system, a comprehensive system debugging should be carried out to ensure the normal and safe operation of the system. Firstly, check that all pipelines and accessories have been correctly installed, and that the appearance of the heating cable is intact and undamaged. Afterwards, disconnect the air protection switches of all circuits, use a shaking table to detect each circuit and make records. Before powering on, it is necessary to measure whether the power cord is connected, whether the heating cable is connected, check whether the electric heat tracing temperature sensor is connected properly, and whether the temperature regulator is connected properly. Check if the system starts smoothly through testing, and also check if all switches and display lights in the power box are working properly. Power on for trial operation, adjust the working temperature of the electric tracing, reduce or increase the working temperature three times, and check whether the heating cable is tracing normally. Observe three heating cycles and record the time of each cycle. Conduct accident alarm experiments, including circuit breaking experiments, leakage experiments, and high-temperature and low-temperature experiments, observe and record the experimental process. In cold environmental temperatures, it is necessary to observe the working condition and cycle of electric heat tracing. Finally, after the system testing is completed, fill out the debugging report. Electric heat tracing products can be widely used in industries such as petroleum, chemical, power, medicine, machinery, food, and ships for heat tracing insulation, antifreeze, and anti condensation of pipelines, pump bodies, valves, tanks, and tank volumes. They are a method for maintaining process temperature * * * in infusion pipelines and storage medium tanks. Electric heat tracing is not only suitable for various places where steam heat tracing is used, but also can solve problems that steam heat tracing is difficult to solve, such as heat tracing for long-distance pipelines and narrow spaces; Equipment with irregular shapes (such as pumps) for heat tracing; No steam heat source or heat tracing for pipelines and equipment in remote areas; Heat tracing for plastic and non-metallic pipelines, etc. The main application scenarios are as follows:

▲ Winter anti freezing cracking of industrial and civil water pipes

▲ Insulation and heat tracing of liquid transportation pipelines in industrial and mining enterprises

▲ Insulation and heat tracing of enterprise steam transmission pipelines

▲ Insulation of compressed air, gas and natural gas transmission pipelines in industrial and mining enterprises

Winter antifreeze of urban fire protection system

▲ Insulation and Heating of Gas Liquid Storage Tanks in Industrial and Mining Enterprises

Winter antifreeze of industrial and civil pipeline valves

▲ Winter insulation for special instruments and meters

Winter de icing and snow removal of important roads and places

Winter heating for industrial and civil buildings

1,. Accompanying tropical core conductor

Electric heat tracing tape is a flat long strip, and the quality of its conductive core wire is directly related to the quality of the heat tracing tape. Usually, tin plated copper wire is used as the conductive core wire, and the quality of the copper wire directly affects the insulation effect. Of course, the quality of the conductor is controlled by the manufacturer. How can consumers distinguish the quality of the conductor? The conductor of the heat tracing strip is generally made of 7 strands of tinned copper wire twisted together. The amount of conductor used directly affects the cost price of the heat tracing strip. Some manufacturers have reduced the cross-sectional area of copper in order to reduce costs. Based on years of customer feedback, Ruihua has made a more reasonable design by increasing the conductor cross-section and using a 7 * 0.52 (1.5 square) core. However, in today's fiercely competitive cable industry, the mainstream heat tracing core in the market is still a 7 * 0.43 (1.0 square) conductor. This type of heat tracing strip has a serious drawback of excessive starting current, which will be mentioned in the following text.

2. Starting current of the tropical zone

The PTC core strip of the electric heating belt is the core part of the electric heating belt, and it is not easy for manufacturers to master its core technology. The key is the starting current size and decay rate. The starting current refers to the peak current generated instantly when the electric heating belt is connected to the power supply. It has decisive significance for the quality of electric heating belts and is a key parameter reflecting the manufacturing technology level of electric heating belts. If the starting current is large, the length of the electric heating belt of a single power source will be correspondingly shortened. At the same time, each time it is started, it will also damage the electrical contact interface between the PTC layer and the conductive wire core, shorten the service life of the electric heating belt, and pose a great safety hazard. At present, the starting current of most domestic manufacturers' products is generally around 0.6~1.2A/m, while the products of American Raychem Company are below 0.5A/m. However, our company's Ruihua brand electric heating belt, which has been technologically improved and produced, can control the starting current of low-temperature electric heating belts below 0.3A/m, and the starting current of medium temperature electric heating belts can be controlled at around 0.3A/m, reaching the international level of technology. Therefore, when purchasing electric heating belts, users and friends must understand the important technical parameter of starting current. If conditions permit, it is best to test it yourself and try to choose products with smaller starting current to avoid unnecessary losses to themselves and the company. Expert friendly reminder for electric heat tracing!

3. PTC irradiation process

1. After the PTC core strip of the electric heating belt is made, it needs to undergo irradiation crosslinking to have * PTC effect. The quality of crosslinking determines the stability and service life of the core strip performance. At present, high-energy electron irradiation crosslinking is commonly used in China, and the appropriate irradiation dose is determined according to the PTC material system. In addition, the dose rate should not be too high, and the linear velocity during irradiation should be uniform, while controlling the tension and friction during operation. Some domestic factories have not undergone radiation cross-linking for their heating belts, which seems to save costs for users. However, there are significant safety hazards involved. The insulation layer that has not been irradiated and cross-linked is poor in terms of heat resistance and aging resistance. Over a long period of time, it is easy to have leakage, short circuit and damage the performance of the PTC core belt, which greatly shortens the service life of the ribbon heater. The Ruihua brand ribbon heater launched by our company has good heat resistance and aging resistance through overall irradiation crosslinking. During use, not only does it extend the service life of the electric heating belt, but it also improves its safety. So how to distinguish the irradiation process of electric heating belts? Firstly, we can observe the situation from the surface of the insulation layer of the electric heating belt; The insulation layer of the electric heating belt irradiated as a whole may have some hardness, while the insulation layer of the electric heating belt irradiated only on the core tape is relatively soft. Consumers should pay attention! Secondly, the insulation layer of the overall irradiated electric heating belt cannot be pulled back and forth (electric heating belts that can be pulled back and forth in their insulation layer do not belong to high-quality electric heating belts). At the same time, when such an electric heating strip is energized to generate heat, the insulation layer that has not been irradiated shrinks greatly. Due to the shrinkage of the insulation layer, the semiconductor PTC core strip is exposed, which can easily lead to leakage and short circuit, posing a great safety hazard

Application areas of heat tracing cables

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Electric heat tracing products can be widely used in industries such as petroleum, chemical, power, medicine, machinery, food, and ships for heat tracing insulation, antifreeze, and anti condensation of pipelines, pump bodies, valves, tanks, and tank volumes. They are a method for maintaining process temperature * * * in infusion pipelines and storage medium tanks. Electric heat tracing is not only suitable for various places where steam heat tracing is used, but also can solve problems that steam heat tracing is difficult to solve, such as heat tracing for long-distance pipelines and narrow spaces; Equipment with irregular shapes (such as pumps) for heat tracing; No steam heat source or heat tracing for pipelines and equipment in remote areas; Heat tracing for plastic and non-metallic pipelines, etc. The main application scenarios are as follows:

▲ Winter anti freezing cracking of industrial and civil water pipes

▲ Insulation and heat tracing of liquid transportation pipelines in industrial and mining enterprises

▲ Insulation and heat tracing of enterprise steam transmission pipelines

▲ Insulation of compressed air, gas and natural gas transmission pipelines in industrial and mining enterprises

Winter antifreeze of urban fire protection system

▲ Insulation and Heating of Gas Liquid Storage Tanks in Industrial and Mining Enterprises

Winter antifreeze of industrial and civil pipeline valves

▲ Winter insulation for special instruments and meters

Winter de icing and snow removal of important roads and places