What is Radiant Tube
Radiant tubes are tubular heating elements designed to emit radiant heat. They are typically made of durable material such as stainless steel, ensuring high-temperature resistance as well as longevity. Used in extremely demanding environments, radiant tubes are leak-proof and corrosion-resistant, among other unique features. Radiant tubes are primarily used in heating systems, where their ability to transfer heat through radiation plays a crucial role.
Radiant tubes are seamless tubes that are made up of heat-resistant materials like iron-chromium-aluminium alloys, nickel-based alloys, etc. Stainless steel tubes are commonly used due to their excellent heat resistance and durability. Operating temperatures of up to 1100 °C are supported by these alloys. Radiant tubes can function independently or in conjunction with bundle rod heaters. When used with bundle rod heaters, they can be used for temperatures up to 1400 °C and have superior performance.
Radiant tubes offer significant reductions in running costs. Not only can they continue to heat the space even when turned off, but they are also a low-energy heating option. You may save up to 65% on your future fuel costs and reduce your carbon footprint.
Although radiant tubes are a low-energy heating system, they provide very even heat coverage throughout the desired space.
Unlike other heating systems, radiant tubes do not directly heat the air. Instead, they operate similarly to the sun by heating via infrared waves. These waves travel through the air and dissipate as heat onto people and objects in the room, creating a consistent room temperature. This makes radiant tubes ideal for areas with high air infiltration, such as warehouses with open bay doors.
Radiant tubes heat the room to the desired temperature within just a few minutes, minimizing energy wasted during warm-up times. If the room is exposed to a colder temperature, such as when a door is opened, the system can quickly recover and reheat the space.
Because the tubes direct heat downward towards the desired space and its occupants, heat loss through the roof is minimized compared to other systems.
This type of system is very easy to install, though it is advisable to use a professional heating specialist to ensure safe and correct installation. Once installed, it is a low-maintenance system that operates without the need to bleed radiators or check water pressure, unlike more traditional heating systems.
Radiant tube systems are also easy to control, allowing you to quickly adjust the temperature for different areas. You can set operating times to ensure that the space is warm for employees as soon as they arrive, and set it to switch off an hour before the end of the working day, knowing that the space will remain at the correct temperature.
Radiant Tubes Uses
Heat Treatment with Protective Atmosphere
Radiant tubes are used for heat treatment processes where a protective atmosphere is required.
Uniform Temperature Distribution
They provide uniform temperature distribution in a furnace, allowing for precise control over both heating and cooling temperatures.
Separation of Material from Combustion Gases
Radiant tubes are beneficial in situations where the material being heated needs to be separated from combustion gases and where there are significant air changes.
Heating Liquids and Salt Melting Furnaces
They are used for heating liquids and as a heat source in salt melting furnaces.
Low Operating Cost, High Efficiency, and Low Noise
Ideal for applications requiring low operating costs, high efficiency, and minimal noise.
Heating Slender Components with Few Burners
Suitable for heating slender components with a small number of burners, such as in roller furnaces and small pusher furnaces.
Heating Efficiency of Radiant Tubes
The heat energy in heating furnaces is generally provided by the combustion of combustible gases such as natural gas. However, the harmful gases generated during this combustion can negatively affect the environment required for heat treatment in the furnace. To address this, the radiant tube was invented to burn combustible gas within the tube itself. Thermal energy is then radiated into the furnace by the radiant tube, preventing harmful gases from contaminating the furnace environment. Since the radiant tube heats the workpiece through tube wall radiation, its heating efficiency directly impacts the effectiveness of heat treatment. Thus, the heating efficiency of the radiant tube is a key characteristic.
The earliest radiant tube, invented and used in Germany in the 1930s, was a single-layer straight tube that passed horizontally or vertically through the furnace. U-shaped radiant tubes were introduced in the early 1950s. To improve heating efficiency, the W-type radiant tube was developed from the U-type. With technological advancements, the P-type radiant tube, a typical example, emerged. Further innovations aimed at increasing heating efficiency led to the creation of hemp-surfaced radiant tubes. These tubes, compared to smooth-surfaced radiant tubes, increased the heating area by more than 30%, significantly enhancing heating efficiency.
The evolution of radiant tubes generally follows two technological routes:
Evolution of Geometric Shapes
The evolution of geometric shapes involves coordination between subsystems and supersystems. The path includes: straight lines → 2D curves → 3D curves → complex curves. Currently, the system is at the 2D curve stage. Designing radiant tubes as 3D curves, such as corrugated tubes, can further improve heating efficiency.
Evolution of Surface Shape
The evolution of surface shape follows: smooth surface → convex surface → rough surface → active material. The system is currently evolving with raised surfaces. Increasing the number of surface protrusions or designing the surface as rough can enhance heating efficiency.
Uniformity of Temperature Distribution on the Surface of the Radiant Tube
The uniformity of temperature distribution on the surface of a radiant tube is a crucial performance indicator. It affects the heating capacity, quality, and service life of the tube. Currently, U-type and W-type radiant tubes are the most commonly used. In the original design, radiant tubes were equipped with a burner at one end, causing significant temperature differences between the two ends. To improve temperature uniformity, core blocks were added to the tube to fill it with high-temperature gas, enhancing convective heat transfer and increasing the temperature at the tail. Later, to further improve temperature uniformity, burners were installed at both ends, and pulse combustion technology was introduced. Additionally, by adjusting the combustion reversing time of the burners at both ends, temperature uniformity could be further improved.
Temperature uniformity is closely related to the length of the flame. Initially, burners could only perform single-stage combustion. Two-stage burners, which allow the control of primary and secondary air ratios, were developed to adjust flame length and improve temperature uniformity. The advent of regenerative combustion technology has significantly enhanced temperature uniformity. Experiments have shown that as the air preheating temperature increases, the maximum temperature difference on the surface of the radiant tube decreases, and the temperature unevenness coefficient also drops.
There are two technological evolution routes in this process:
Evolutionary Path to Supersystem
The path involves transitioning from a single system → dual system → multiple systems. According to this route, the system is in the final stage of evolution, with heat storage bodies replacing control systems.
Frequency-Coordinated Evolutionary Path of a Single Object (Flame)
The path involves continuous motion → pulse → periodic action → increased frequency → resonance. Currently, the system is in the cyclical stage of evolution. Further improvement can be achieved by enhancing the combustion cycle of burners on both sides or by increasing the frequency of alternating nozzles on both sides to improve temperature distribution uniformity.
7 Things to Consider When Choosing and Installing Radiant Tube Heaters
Radiant tube heaters are an efficient and cost-effective solution for heating industrial spaces, warehouses, and commercial buildings. However, making the wrong choices during selection and installation can lead to suboptimal performance, energy wastage, and safety hazards. In this article, we'll delve into the common pitfalls to avoid when dealing with gas tube heaters.
Mistake: Choosing an infrared heater that's too small or too large for your space can result in inefficient heating. An undersized heater won't provide adequate warmth, while an oversized one may waste energy and cause discomfort.
Solution: Calculate the required heat output based on the dimensions of your area, insulation levels, and desired temperature rise.
Mistake: Failing to maintain proper clearance distances between radiant tube heaters and combustible materials (such as walls, ceilings, and stored items) can lead to fire hazards.
Solution: Follow manufacturer guidelines for minimum clearance distances. Install heat shields or protective barriers where necessary.
Mistake: Incorrect placement of infrared heaters can lead to uneven heating, cold spots, and discomfort for occupants.
Solution: Position heaters strategically to achieve uniform heat distribution. Consider factors like ceiling height, obstructions, and airflow patterns.
Mistake: Radiant tube heaters require adequate ventilation to ensure complete combustion and prevent the buildup of harmful gases.
Solution: Provide sufficient fresh air intake and exhaust vents. Regularly inspect and clean the burner assembly and flue system.
Mistake: Neglecting routine maintenance can reduce efficiency, increase energy consumption, and shorten the lifespan of your gas tube heater.
Solution: Schedule annual inspections, clean the reflectors, check gas connections, and replace worn-out components promptly.
Mistake: Using the wrong gas type or inadequate gas pressure can affect heater performance and safety.
Solution: Verify the correct gas type (natural gas or propane) and ensure proper pressure levels. Consult a licensed gas technician if needed.
Mistake: Improper installation by inexperienced individuals can compromise safety and functionality.
Solution: Hire a qualified HVAC technician for installation. They'll ensure proper alignment, secure mounting, and adherence to safety standards.
How to Choose a Radiant Tube for Your Furnace and Budget
Determine Your Furnace Needs
Before exploring the various options available, it's important to assess your specific furnace requirements. Consider the type of fuel your furnace uses, the desired heat output, and the size of the heating space. Additionally, evaluate any industry regulations or safety standards that may apply. By understanding these factors, you can clearly define the type and specifications of the radiant tube needed for your furnace.
Consider Tube Material and Design
Radiant tubes are typically made from stainless steel, alumina, or ceramic materials. Each material has unique properties, so it's essential to choose one that meets your furnace's requirements and fits your budget. Stainless steel is popular due to its durability and suitability for high-temperature applications. Alumina and ceramic tubes offer excellent heat resistance but tend to be more expensive. Assess the temperature range your furnace operates within and select a material that balances cost and performance effectively.
Additionally, pay attention to the design of the radiant tube. The shape, size, and placement of the burner ports, as well as the arrangement of the fins or baffles, are crucial for efficient heat transfer. Opting for a well-designed radiant tube can maximize heat transfer, improve fuel efficiency, and reduce long-term maintenance costs.
Set a Realistic Budget
While investing in a quality radiant tube for your furnace is important, setting a realistic budget is equally crucial. Start by researching prices and product reviews to understand the market range. Consider factors such as initial purchase cost, installation expenses, and long-term maintenance requirements. Remember that a higher upfront investment may save you money in the long term by providing better performance, energy efficiency, and durability.
Our Factory
China Welong was founded in 2001, which is a professional international integrated supply chain service provider. We are concentrating on the industrial customized metal products, aiming at empowering the world with the finest supply chain of China. Since the establishment, we are offering Supplier Development & Management, Purchasing Supervising, Quality Control services in China for many leading enterprises in the fields of International Industrial Manufacture, Oil Drilling, Aerospace & High-end Medical Treatment.
Certifications
FAQ
Q: Are radiant tube heaters efficient?
Q: Is a radiant heater cheap to run?
Q: Do radiant heaters really work?
Q: What does a radiant tube heater do?
Q: How do radiant tubes work?
Q: What is the difference between convection and radiant tubes?
Q: What is meant by radiant tubes?
Q: How long does radiant heat tubing last?
Q: How deep should radiant tubing be?
Q: What is the function of the radiant tube?
Q: What is the composition of radiant tube?
Q: How thick is radiant tubing?
Q: How deep should radiant tubing be in concrete?
Q: Should radiant tubing go above or below rebar?
Q: How do radiant tubes work?
Hot Tags: radiant tube, China radiant tube manufacturers, suppliers, factory, Casting, Closed Die Forging Process, Arms for continuous galvanizing line, Forging, Centrifugal casting and machining, Sand Casting and Machining and Painting
