SRY4-220/5 Tubular Electric Heater
1. The element is allowed to work under the following conditions: A. Relative humidity of air not greater than 95%, no explosive or corrosive gases. B. Working voltage should not exceed 1.1 times the rated value, and the shell should be effectively grounded. C. Insulation resistance ≥1MΩ; Dielectric strength: 2KV/1min.
2. The electric heating tube should be properly positioned and fixed. The effective heating zone must be completely immersed in liquid or solid metal. Dry burning is strictly prohibited. If scale or carbon deposits are found on the tube surface, they should be cleaned promptly before reuse to avoid affecting heat dissipation and shortening service life.
3. When heating fusible metals or solid nitrates, alkalis, asphalt, paraffin, etc., first reduce the operating voltage, and only after the medium melts can it be raised to the rated voltage.
4. When heating air, the elements should be arranged crosswise and evenly to ensure good heat dissipation conditions and allow the flowing air to be fully heated.
5. When heating nitrates, safety measures should be considered to prevent explosion accidents.
6. The wiring part should be placed outside the insulation layer to avoid contact with corrosive, explosive media, and moisture. The lead wires should be able to withstand the temperature of the wiring part and the heating load for a long time. When tightening the wiring screws, avoid excessive force.
7. The element should be stored in a dry place. If the insulation resistance drops below 1MΩ due to long-term storage, it can be dried in an oven at about 200°C or heated by reducing voltage until the insulation resistance is restored.
8. The magnesium oxide powder at the outlet end of the electric heating tube should be protected from contaminants and moisture at the usage site to prevent leakage accidents.
SRY4-220/5 Tubular Electric Heater
In the production process of electric heating tubes, blackening treatment is sometimes used. Heat treatment is a process for heat treating stainless steel and other metal objects. After treatment, a layer of oxide film forms on the surface to achieve anti-corrosion and anti-rust purposes. After heat treatment, the surface wear resistance and hardness of the heating tube are improved without affecting the internal components of the electric heating tube.
Under normal working conditions, the simplest method for blackening the surface of electric heating tubes involves the following steps:
1. First, clean the surface of the metal tube to keep it clean;
2. Second, perform degreasing treatment on the surface. This process can fully immerse the metal tube in a degreasing solution. The pH value of the degreasing solution is around 13, and the time is not less than half an hour. After degreasing, rinse with clean water.
3. Next, pickling can be carried out. The pH value of the pickling solution is around 3, and the treatment time should not exceed 10 minutes. After pickling, rinse with clean water;
4. Blackening treatment: The pH value of the bath solution is between 2-4, and the treatment time is about 10 minutes. After blackening, clean thoroughly;
5. Finally, dry and oil;
Following the above five steps is a very effective method for blackening electric heating tubes.
The typical structure of a metal tubular electric heating tube (the most common structure) generally consists of five parts: insulator, sealing material, lead rod, filler, heating wire, metal sheath tube, and terminal.
The spiral heating wire and lead rod are located in the center of the metal sheath tube. The manufacturing process involves threading the spiral heating wire into a seamless steel tube, copper tube, or aluminum tube, and then uniformly filling the gaps with an insulating and thermally conductive oxide medium, such as crystalline magnesium oxide powder (or alumina, clean quartz sand, etc.) using a multi-tube filling machine. Then, a tube shrinking machine is used to reduce the tube diameter, making the oxide medium dense (density above 3.3g/cm³), ensuring that the heating wire is isolated from air and does not shift from the center to touch the tube wall. In this way, the heat output per unit area can be increased more than tenfold, and the service life can be correspondingly increased to over 10 years. Compared with heating elements of the same heat output, tubular electric heating tubes can save 5% of heating material, and the thermal efficiency can reach over 90%.
Therefore, from the structure of the electric heating tube, the metal tubular electric heating tube is currently the most widely used, simple in structure, reliable in performance, and long in service life as a sealed electric heating element. It can be successfully applied in industry and household appliances, and its use is becoming more widespread. It is hoped that more users will have a clear understanding of the structural principles of electric heating tubes.
Common Types
Fin Electric Heating Tube
A fin electric heating tube is a device that converts electrical energy into heat to heat the material to be heated. During operation, the low-temperature fluid medium enters the input port under pressure through the pipeline, flows along a specific heat exchange channel inside the electric heating container, designed based on fluid thermodynamics principles, and carries away the high-temperature thermal energy generated by the electric heating element during operation, raising the temperature of the heated medium. The finned tubular electric heating element has metal散热片 wound on the surface of the ordinary element, expanding the heat dissipation area by 2 to 3 times compared to ordinary elements. That is, the surface power load allowed for fin elements is 3 to 4 times that of ordinary elements. Due to the shortened length of the element, its own heat loss is reduced. Under the same power conditions, it has the advantages of fast heating, high thermal efficiency, long service life, small heating device volume, and low cost. It can be installed in air duct systems or other heating applications for stationary or flowing air.
Flange Electric Heating Tube
A flange electric heating tube (also called an immersion electric heater) uses U-shaped tubular electric heating elements. According to the design specifications for heating different media, it is assembled on a flange cover according to power configuration requirements and inserted into the material to be heated. The large amount of heat generated by the heating element during operation is conducted to the heated medium, raising its temperature to meet the required process requirements. When the medium temperature reaches the set value of the process requirements, the control system adjusts the output power of the electric heater based on the temperature sensor signal through PID calculation, achieving temperature control of the resistive load of the heating element. This makes the medium temperature uniform and meets the requirements. When the heating element overheats or the liquid level is low, the interlock protection device immediately cuts off the heating power to prevent the heating element from burning out and extend its service life. Flange electric heating tubes are mainly used for heat preservation and heating of materials in various storage tanks, containers, and oil tanks in industries such as petroleum, chemical, food, and machinery. The connection method can be flange type or threaded end face sealing.
Titanium Electric Heating Tube
A titanium electric heating tube uses a titanium tube as the shell. Along the central axis inside the tube, electric heating alloy wires are evenly distributed, and the gaps are filled with compacted magnesium oxide sand with good insulation and thermal conductivity. The tube ends are sealed with silicone or ceramic. This metal electric heating element is specially designed for highly corrosive liquids. Titanium electric heating tubes have the characteristics of simple structure, high mechanical strength, high thermal efficiency, safety and reliability, easy installation, and long service life. They are widely used in various highly corrosive liquids. Titanium has a low specific gravity and is widely used for heating water, nitrate solutions, acid solutions, and alkali solutions. Practice has proven that titanium has high efficiency and long life in anti-corrosion equipment production applications. In electroplating equipment applications, it does not affect the plating solution and can greatly improve the efficiency of the electroplating industry. The effective length of the heating element must be fully immersed in the liquid during use.
Teflon
Teflon electric heating tubes are a new type of strong corrosion-resistant electric heating tube used for heating various corrosive liquids. They have excellent aging resistance and good flexibility, with low surface load design. The joints are fully sealed against acid and alkali, and the non-heating section and over-temperature safety protection system are customized according to customer requirements. It ensures that the heater is not easily burned out, has a long service life, is fully sealed, non-toxic, leak-free, with grounding protection, and is safe and reliable. The applicable temperature is below 110°C. Anti-corrosion Teflon electric heating tubes have the advantages of high thermal efficiency, energy saving, and high cost performance. They can be designed in various structural forms, such as spiral, L-shaped, U-shaped, W-shaped, mosquito coil-shaped, and combined types. They have been recognized by many listed companies and serve as long-term suppliers of mosquito coil-shaped Teflon electric heaters. We can undertake non-standard products. In terms of voltage, power, specification size, product shape, and wiring method, engineers can design according to customer requirements. We welcome customers to provide drawings or samples for custom production.
Quartz Electric Heating Tube
Quartz heating tubes are most commonly carbon fiber quartz heating tubes.
Carbon fiber heating tubes, also known as carbon fiber electric heating tubes, infrared heating tubes, infrared electric heating tubes, carbon fiber infrared electric heating tubes, carbon fiber infrared heating tubes, etc. They consist of a carbon fiber filament placed in a quartz tube, which is vacuum-sealed. Voltage is applied to the carbon fiber filament, causing it to generate heat. Our company's products use imported carbon fiber heating elements, with advantages such as large power margin, high temperature resistance, strong heating capacity, long service life, and adjustable power.
Radiant Electric Heating Tube
A radiant heating tube encloses the electric heating element in a protective sleeve, which is energized to generate heat. The sleeve indirectly radiates heat to the furnace lining and the workpiece being treated. It is widely used in various heating furnaces in the heat treatment industry. The electric heating alloy material used in radiant heating tubes should have high resistivity and high electrothermal conversion efficiency. Since the radiant tube is placed inside the sleeve, the heat transfer process is different from that of ordinary exposed heating elements. The heat shielding is large, and the element temperature must be controlled during the heating process to prevent overheating. When the radiant tube is heated in a closed manner, the surface temperature of the electric heating element is about 100°C-150°C higher than the furnace temperature. Therefore, when selecting materials, it is necessary to analyze the furnace temperature and the atmosphere inside the furnace to choose the correct heating material.
