Extremes like high pressure and high temperature are normal in industrial processes. As a result, certain manufacturing units and plants equip their facilities with specialized equipment to withstand these conditions, including high-temperature fans and blowers.
What separates high-temperature blowers and fans from conventional designs is their structural integrity and high heat resistance. Let’s explore these essential pieces of industrial equipment in more detail.
Classification of High-Temperature Industrial Fans and Blowers
Some manufacturers classify their high-temperature industrial fans and blowers based on different temperature ranges, like operating temperatures of 400°– 600°F, 600°– 800°F, and 800°– 1000°F. Each category represents different builds and materials added to the package to handle the thermal conditions of their operations. Other manufacturers, especially the ones specializing in custom builds, convey the highest temperature their fans and blowers are capable of handling. The highest temperature range available is around 2200°F (1200°C).
The difference between fans (axial) and blowers (centrifugal) is important to consider as well, for different applications, and flow rate and pressure capabilities. The ratings for these capabilities are often cited at ambient conditions and may differ in operating conditions, based on how extensively high temperature is impacting the gas being displaced.
Important Build Considerations
Construction Material
The construction material of various fan/blower components has to be selected not just for the requisite temperature range but also for the level of exposure, heat dissipation properties, internal heat generation, etc. Different alloys have different yield strengths at high temperatures, but they also have different creep strength and oxidation resistance properties, and if the fan’s blade and other components are directly exposed to these deteriorating agents/forces in addition to heat, the material selection becomes a multi-faceted process. Steel alloys, even one of the most commonly used 304 stainless, may only be suitable for temperatures between 600°– 800°F. Specialized stainless allows, and some nickel-chromium alloys are better suited for the job.
The alloy covers elements like shaft, hub and wheel, inlet cone, and housing. High-temperature ceramic/polymer bearings are also available, but metal bearings are the norm. For most other components like stuffing boxes, gaskets, lubrication lines, etc., the choices may vary among high-performance plastics, ceramics, composites, high-temperature silicone, and pure metals (copper mostly, for its conductive properties).
Type of Finish
The type of finish has a significant impact on a fan/blower’s overall and component-wise durability in high-temperature conditions. This includes high-temp paints that often include ceramic and silicone compounds to increase their thermal durability and manage heat transference. Ceramic coating is another common type of finish for certain high-temperature industrial fans and blowers. This type of coating can withstand significantly high temperatures and allow for minimal heat transference to the material underneath, protecting it against high heat conditions. To a lesser extent (for low-grade high temperatures), heat-resistant epoxy, high-temperature silicone, and powder coating finish are also used.
Housing
The housing of high-temperature industrial fans needs to accommodate several thermal and mechanical characteristics and their implications, including expansion. This requires choosing the right material and opting for proper design considerations. Thicker housing walls (compared to fans and blowers designed for ambient conditions), adding heat shields or other secondary thermal insulators to protect components inside the housing, using expansion joints and flexible seals to accommodate for temperature-driven expansion (while balancing for mechanical stress), and specialized welds/joints to withstand extreme heat without degrading.
Cooling
While most high-temperature industrial fans and blowers are air-cooled, some of them may rely upon forced air to cool down (depending on their location and application). Design elements like blade length and shape and housing structure and insulation may also have an impact on its cooling.
Life cycle
The lifecycle of a high-temperature fan and blower is influenced by several factors beyond the extreme environment of its operations. This includes installation, alignment, mechanical stress, periodic maintenance, different wear and tear rates of different components, etc. Unlike fans and blowers operating at ambient conditions, a high-temperature fan/blower will be more vulnerable to certain wear and tear (which may increase the thermal stress on the material/component). Tolerances in these fans (both individually and collectively) are already pushed quite close to the extreme limits, so a smaller degree of degradation may lead to more significant damage to these fans.
Apart from these, other build considerations like choosing the right lubricants that can withstand extreme temperatures, seals and sealants that may not degrade at these temperatures, and control systems to maintain fan/blower rotation at an optimal level, i.e., maintaining operational efficiency without overstressing or overheating the fan/blower.
Applications
High-temperature industrial fans and blowers have several industrial applications, including:
Cement Plant: They are used in several cement manufacturing operations, including preheating, kilns, heat recovery systems, dust collectors, etc. However, preheaters and kilns stand out from the rest due to extreme conditions. Preheaters reach temperatures of 800-900°C while Kilns can reach as high as 1450°C. Fans and blowers facilitate requisite air/gas flow and exhaust, exposing them to extreme temperatures.
Steel Manufacturing: High-temperature fans are used in blast furnaces to ensure an adequate amount of air supply for smelting. The temperatures there can reach up to 2200°C and the fans are used to push in preheated air (temperatures ranging from 900-1,300°C). The fans are also used in the steel cooling process. High-temperature industrial blowers are often used in fume extraction and dust control.
Pulp and Paper: High temperature environments vary greatly in the pulp and paper industry, with extremes reaching to 1000°C for drying sections that use natural gas heaters. High-temperature industrial fans are often used in these drying sections while blowers are used in the pulping and screening segments.
Energy Recovery Systems: These systems can be deployed in different industries or operate independently. They require high-temperature fans in heat exchangers as well as cooling systems. Blowers can be used for supplying air for consumption or directing flue gas. For most such systems, the high temperatures are lower than the ones in cement plants and steel manufacturing.
Other applications include trash incineration (Temperatures can reach 1200°C) and glass making (temperatures reaching up to 1700°C).
Centaxia Industrial Air Solutions provides air movement solutions to various industries with its industrial fan and blower lines. For queries regarding anything related to industrial air solutions, give the Centaxia experts a call at 888-656-0444.