Industrial fans and blowers are machines whose primary function is to provide and accommodate large flows of air or gas to various parts of buildings or other structures. This is achieved by rotating a number of blades, connected to hubs and axes, and driven by a motor or turbine. The flow rate of this mechanical fan ranges from about 200 cubic feet (5.7 m 3 ) to 2,000,000 cubic feet (57,000 m 3 ) per minute. A blower is another name for a fan operating in which the flow resistance is mainly on the downstream side of the fan.
Video Industrial fan
Fungsi dan industri
There are many uses for the continuous air or gas flow generated by industrial fans, including combustion, ventilation, aeration, particulate transport, disposal, refrigeration, air cleaning and drying, to name a few. The industries served include power production, pollution control, metal manufacturing and processing, cement production, mining, petrochemicals, food processing, cryogenics, and clean rooms.
Maps Industrial fan
Centrifugal fan and axial fan
Most industry fans can be categorized into one of two common types: centrifugal fans and axial fans.
Centrifugal
The centrifugal design uses the centrifugal force generated by a rotating disk, with a blade mounted at right angles to the disk, to impart movement to air or gas and increase the pressure. The assembly hubs, discs and blades are known as fan wheels, and often include other components with aerodynamic or structural functions. The centrifugal fan wheel is usually contained in a scroll-shaped fan housing, resembling a nautilus sea shell with a central hole. The air or gas inside the spinning fan is thrown from the exterior of the wheel, into an outlet in the largest diameter of the housing. This simultaneously attracts more air or gas to the wheels through the central hole [1]. Inlets and outlets are often attached to fan housing, to supply and/or dispose of air or gas to industry requirements.
There are many types of centrifugal fans, which may have fan wheels that range from less than 3 cm to more than 16 feet (5 m) in diameter.
Axial
An axial design uses axial force to achieve air or gas movement, rotating the central hub with a blade extending radially from its outer diameter. The liquid is moved parallel to the fan's fan shaft, or the rotation axis. The axial fan wheels are often contained in short sections of the cylinder ductwork, where the inlet and outlet channels can be connected.
An axial fan type has fan wheels of a diameter typically ranging from less than one foot (0.3 meters) to more than 30 feet (9 m), although the axial cooling fan wheel may exceed 82 feet (25 m) in diameter.
In general, the axial fan is used where the main requirement is for large volume flow, and centrifugal design where higher flow and pressure is required.
Design path
There are several paths to determine the fan design for the application.
For industries where the application requirements are not very varied and the applicable fan design has a diameter of about 4 feet (1.2 meters) or less, a standard or pre-engineered design may be selected.
When the application involves more complex specifications or larger fans, then the design based on the existing model configuration will often meet the requirements. Many configuration models already cover a variety of industry processes today. Appropriate models of fan company catalogs are selected, and company engineers apply design rules to calculate dimensions and select options and materials for desired performance, strength, and operating environment.
Some applications require special configuration specific for fan design to meet all specifications.
All industrial fan designs must be accurately engineered to meet performance specifications while maintaining structural integrity. For each application, there are special flow and pressure requirements. Depending on the application, the fan can be subjected to high rotation speed, operating environment with corrosive chemicals or abrasive airflow, and extreme temperatures. Larger fans and higher speeds produce greater force in rotating structures; for safety and reliability, the design must eliminate excessive pressure and favorable resonance frequency. Computer modeling programs for computational fluid dynamics (CFD) and finite element analysis (FEA) are often used in the design process, in addition to testing laboratory scale models. Even after the fan is built, verification may continue, using fan performance testing for flow and pressure, strain gage testing for pressure and tests to record fan resonant frequency.
Fan subtype
The types of fans and their subtypes are industry standards, recognized by all major fan manufacturers.
Centrifugal
One of these fan subtypes can be created with long lasting erosion-resistant liners.
Airfoil (Air foil) - Used for a variety of applications in many industries, fans with perforated blades, airfoil profiles designed for use in airflows where high efficiency and quiet operation are required. They are widely used for sustainable services at ambient and high temperatures in applications of forced and induction designs in metals, chemicals, power plants, paper, stone products, glass, resource recovery, incineration and other industries worldwide.
Reverse curve - This fan has an efficiency almost as high as the airfoil design. The advantage is that the single-thickened curved plate knife prevents the possibility of buildup of dust particles in the blade, which may occur with hollow airfoil spools. The robust design allows high-speed tip operation, and therefore the fan is often used in high-pressure applications.
Skip back - This fan has a simple, back-to-back, flat blade to adjust the airspeed pattern through the fan wheel for high-efficiency operation. These fans are typically used in high-volume, low-volume, and low-pressure clean air applications.
Radial bar - This flat blade is arranged in radial pattern. These rugged fans offer high-pressure capabilities with average efficiency. They are often installed with anti-erosion liners to extend the life of the rotor. The design of this compact house to minimize the needs of floor space.
Radial tipped - This fan has a backward-curved wheel, but in a slightly different way from the fan backward. The rear-curved fan has wheels whose blades are curved outward, while radial-tip fan blades curve inwards and radial at their ends (hence the name "radial tip"), while still in a backward-curved configuration. Their curvature can also be regarded as radial at the tip but gradually tilts toward the rotation. This rugged design is used in high volume flow rate applications when pressure requirements are rather high and resistance to erosion is required. It offers medium efficiency. A common application is the dirty side of the baghouse or precipitator. The design is more compact than airfoil, leaning backward or leaning backwards.
Paddle-wheel - This is an open impeller design without shroud. Although the efficiency is not high, this fan is suitable for applications with very high dust load. It can be offered with a field-replaceable blade liner from ceramic tiles or tungsten carbide. This fan can also be used in high temperature applications.
Front Curve - This "squirrel cage" fan produces the highest volume flow rate (for specific tip speeds) of all centrifugal fans. Therefore, it often has the advantage of offering the smallest physical package available for a given application. This type of fan is usually used in high-temperature furnaces. However, this fan can only be used to drain the air with low dust loads because they are the most sensitive to the accumulation of particles, but also because of the large number of blades required for the front wheel-curve.
Industrial Excellence - This is a low-cost, medium-duty, steep and tilted fan for tiresome gases, carrying chips, etc.
Fans-engineered enthusiasts (PE) - A series of fans with various blade shapes that are usually available only in standard sizes. Being pre-engineered, these fans may be available with a relatively short delivery time. Often, pre-designed rotor with various blade forms can be fitted into the general housing. These are often available in various volume and pressure requirements to meet the needs of many applications.
Pressure blower - This is a low volume low-pressure blower used in air-burning applications in a furnace or for providing air "puffs" for cleaning and/or drying applications.
Blower without surgery - This high-volume, low-volume blower has a downward trend for "waves" (periodic flow rate variations) even at a greatly reduced fan speed. This allows for extreme (low flow) decline without significant beats.
Mechanical steam recovery blower - This specially designed centrifugal fan is designed to increase the temperature and pressure of saturated steam in a closed-loop system.
Acid gas blower - This very heavy construction blower is suitable for inlet pressure from full vacuum up to 100 psig. Materials selected for corrosion resistance to gases and particulates are handled.
Special process gas blower - This blower is for high pressure petrochemical process.
Axial
High temperature axial fans - This is a high volume fan designed to operate against low flow resistance in industrial convection furnaces. They can be either one-way or two-way designs. Very roughly, they are most commonly used in high temperature furnaces (up to 1800 degF) applications.
Axial fan tube - This is a axial fan unit with a fan wheel located in a cylindrical tube, with no inlet damper or outlet.
Vaneaxial fans - These axial flow enthusiasts have higher pressure capabilities due to static propellers.
Field Variable Axial fans - The propeller on this axial fan can be adjusted manually to allow the angle of the blade to be changed. This allows operation through a wider volume/pressure relationship. The vanes are adjusted periodically to optimize efficiency by matching blade pitch to various conditions for application. These fans are often used in mining applications.
Pitch varies on axial axial fans - This is similar to "Axial Pitch Variable Pitch" unless they include an internal mechanism that allows the pitch blade to be adjusted when the rotor fan is in motion. This versatile fan offers high efficiency operations at various operating points. This instant blade adjustment capability is an advantage that is possible only with axial fan only.
Cooling fan - (also referred to as "cooling tower fan") - This is an axial fan, usually in large diameter, for low pressure and large volume of airflow. Applications are in wet mechanical cooling towers, air-cooled steam condensers, air-cooled heat exchangers, radiators, or similar air-cooled applications.
Mixed-flow fans - This fan gas flow pattern resembles a combination of axial and centrifugal patterns, although the fan wheels often look similar to centrifugal wheels. There are different types of mixed-flow fans, including high-pressure, high-pressure fans and blowers.
Flow control
There are several ways to control the fan flow rate, for example, to temporarily reduce the rate of air or gas flow; this can be applied to centrifugal and axial fans.
Speed ​​Variations - All of the above described fan types can be used in conjunction with variable speed drivers. These may be adjustable AC frequency controllers, DC motors and drives, steam turbine drivers, or variable hydraulic speed drive units ("fluid drives"). Flow control by means of variable speed is usually smoother and more efficient than by using damper control. Significant energy savings (with reduced operating costs) are possible if variable speed fan drives are used for applications requiring reduced flow operation for a substantial part of the system's operating life.
Industrial Silencer - This device also allows the fan volumetric flow control during operation, using the panel so as to direct gas flow or restrict the entry or exit area.
There are various silencers available:
Louvered Inlet Box Dampers - Damper Inlet Radial Variable Inlet Vane (VIV) Damper
Vortex Dampers - Damper Discharge -
See also
- Fan (mechanic)
- Axial fan design
- Special fan power
- Loss of three dimensions and correlation in turbo engine
References
External links
- Association of Movement and Air Control (AMCA)
- Axial flow enthusiasts online calculations: Free basic fan design tools for axial flow fan and axial power curve, cpu-cooling, industrial fan calculations, detail packs available for download
Source of the article : Wikipedia
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