When it comes to heating air, fluids, gasses, and surfaces there are numerous factors for a prospective customer to take into consideration. Among the many determining circumstances to ponder are what is to be heated, cost efficiency, energy efficiency, and safety just to name a few.
These heating elements transfer heat through the methods of conduction, convection, or radiation. This is largely dependent upon whether a surface, space, liquid, or gas is what is to be heated. Increasingly, tubular heaters are becoming the clear choice for many manufacturers, industrialists, and homeowners because of their diverse applications, compact makeup, and also their relatively low energy requirements in comparison to the functions they perform.
These heaters are the most commonly used for many reasons, and they get their name from the tubular element that radiates thermal energy. The designs of tubular heating elements are highly customizable so that they can be suited to fit any otherwise compatible device or purpose. The shape can even be modified to fit pre-existing appliances and in many cases, this modification can be accomplished by the end user.
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Design of Tubular Heaters
The basic construct of this heating mechanism is a coil heating element that spawns heat and is encased in a heating element binder that is surrounded by magnesium oxide powder and vibration loaded. This ensures that the heater density throughout maintains an optimal level of performance.
The coil itself is forged from a high resistance metal called nichrome, which is an alloy composed of 80% nickel and 20% chrome. This method is the antithesis of the usual use of electricity in that the metallic materials used in the making of tubular elements are not designed to pass the electricity through the nichrome wire, but rather to hold the electricity in the coil. This is what produces the thermal energy that is radiated.
Industry standards dictate that these heating elements must have a resistance tolerance of +10% -5% and +5 -10% watts. Magnesium oxide powder is used for insulation because of the proficient thermal conductivity that it provides as well as its dielectric strength. This insulating agent is hygroscopic, meaning that it can absorb moisture from the air and cause corrosion over time.
Following the application of the magnesium oxide power, the coil undergoes a rolling process that acts on the coil as a compressing agent and maintains this state of compression within the center of the heater until the diameter of the coil is reduced to a satisfactory level. The binding and its inner coil are then sheathed in a material suitable for the specific purpose that the coil is to serve. The electricity that travels through the coil is then transformed into heat and emanates from the sheath. This method of heating is why such heaters are also called resistance heaters.
Benefits of Tubular Heaters
It is likely that the most endearing characteristics of tubular heating elements are their pliability and the ease with which they can be mounted or installed. Heating tubes undergo a process called annealing that induces a state at which the heating apparatus is softened. This softening procedure renders the heating coils flexible and ready to be shaped to fit any compatible surface and inside of heaters as well. These devices are designed to use conduction, convection, or radiant methods to transfer heat.
Tubular heaters are the most versatile, energy efficient, and cost efficient heating elements that the industry has to offer. Their pliability and ease of installation make them a premium choice for any homeowner or industrialist. There are sizes, configurations, and compositions of tube elements for the handyman at heart who needs a new heating element for the dishwasher and the maintenance man who is tasked with repairing heavy duty equipment that relies on a high thermal energy output. This miracle heater is just as suited for the outdoorsman who needs radiant tube heaters for the upcoming camping trip and the easily chilled mother who needs a small space heater for the office. For cost-efficiency, numerous applications, and top-notch performance, the tubular heater is the people's choice.
Types of Sheathing
The type and quality of sheathing used for a heating element is of the utmost importance. This covering is typically constructed from one of several grades of rubber, steel, stainless steel, and copper depending on what the tubular heating element will be used to heat. It is crucial to the safety and overall endurance of the heating element that the correct and most compatible material is used to fashion the sheath.
- Incoloy 800
- When used for sheathing, has a higher level of nickel than its other rubber counterpart. This serves to make the sheath more resistant to scaling and corrosion. This sheathing can endure temperatures up to 1600 degrees Fahrenheit or 871 Celsius. This particular grade of rubber is used when the element will be used to heat air; it is suitable for immersion in palatable water and other liquids.
- Incoloy 840
- Another grade of rubber utilized to encase the coil and binding. This version is less susceptible to oxidation than the 800 variety of Incoloy rubber and it is most commonly used to heat air. While the composition of this rubber differs slightly to the 800 selection and has different applications, it is of the same thermal energy caliber.
- 304 Stainless Steel
- Of the stainless steel assortment, the 304 stainless steel is the most basically composed. This type of sheathing is common in the food industry, and it is also oftentimes used in medical and chemical heating. This material is designed to perform at temperatures up to 1200 degrees Fahrenheit or 649 degrees Celsius.
- 316 Stainless Steel
- Has Molybdenum added to its substance for added support in its battle against corrosion, especially in exercises that involve the presence of chlorides. The amount of heat that 316 stainless steel can operate at is equal to that of the 304 composition.
- 321 Stainless Steel
- Designed to endure the same temperatures as varieties of stainless steel. What sets this incarnation apart is the presence of titanium that aids against the intergranular corrosion that is infamous in mediums administering in the 800 to 1200 degree range.
- Regular Grade Steel
- Also employed in sheathing in heating elements. It is typically utilized in high to low viscosity oils, asphalt, tar, wax, and transfer liquid media.
- Using Copper
- Used when the element will be used for low heat purposes. One of the biggest draws for copper is that it is inexpensive and can be used for clean water heating. This material can withstand temperatures up to 700 degrees Fahrenheit and 399 degrees Celsius.
Types of Comfort Tubular Heaters
Tube heaters are just as proficient for comfort heating purposes as they are as parts of a larger appliance or industrial machine. They come in several styles and methods of operation that make them suitable for indoor or outdoor use.
- Electric Tubular Heaters
- The most commonly used resistance comfort heaters. Tubular electric heaters operate by radiating low wattage background heat and are much safer than gas, oil, and propane tube heaters. They are compact and can be mounted as a wall heater or used as a floor heater. Electric tube heaters perform best when they are mounted horizontally. This aids in ensuring that the heat is pushed upward. Even in their diminutive state, these tubular electric heaters can heat an entire room, but they are better when used in conjunction with a central heating system. The electric tube heater shuts off when it overheats as an added safety bonus.
- Radiant Tube Heaters
- Just like the name implies, this particular heater uses the radiant transfer approach. This heater can achieve high temperatures which are generated by heating propane, natural gas, or oil. The heat travels through a metal tube to its destination which is a surface with heating coils that radiate thermal energy. The propane tube heater is the most commonly used radiant tubular heater. These heaters are found in several incarnations as outdoor patio heaters and are even used to heat construction sites. There are even some powerful enough to heat whole buildings. The propane tube heater is the tube heater best suited to outdoor use or heating large areas.
- Thermostatic Tubular Heater
- At the cutting edge of thermal solutions. Unlike other tubular element based heaters, this one can be set to a specific temperature. Such a feature comes in handy for sterilization purposes when too much heat could cause charring and too little heat would not suffice to complete the sterilization process. There are also thermostats that can be mounted to certain tube heaters that do not come pre-equipped with one.
Uses for Tubular Heating Elements
Tubular elements come in many shapes and sizes and are capable of performing a plethora of heating related functions. Their versatility lends them employment in household, industrial, and commercial duties, and their cost efficiency makes them affordable for all.
Tubular heating finds much meaningful work in household applications as they are an integral part of many appliances that people use on a daily basis. Dishwashers, clothes dryers, and ovens apply this crafty warming method. Among the main features that make them so attractive for use on household appliances is their relative safety.
There are even corrosion resistant and explosion proof models. Furthermore, the simplicity associated with installing these elements makes them ideal for everyone for the do-it-yourselfer as well as those who subscribe to the "Do it for me, please!" school of thought.
Tubular heating also features prominently in the foodservice industry. They figure in at the commercial level in restaurants where they are commonly used for the purpose of immersion in deep-frying applications. Tubular elements are also heavily relied upon in food processing plants.
Cost efficiency and versatility make resistance heating ideal for many heavy duty operations as well. This device has found a home in the field of oil refinery as it is used via the immersion technique. Tubular elements can be constructed to operate in petroleum based fluids and natural gasses, too. They are even put to use at paper mills as well as being enlisted for the purpose of heating water storage tanks. Other uses include but are not limited to: heating elements for coffee makers, climate controlled research, safe heating option for zoo animals, plastic injection molds, packaging equipment, labeling machines, and hot stamping. Though resistance heaters are a multi-service invention, they are still most commonly used as comfort heaters.