Didw Centrifugal Blower and Fans Manufacturer
Didw centrifugal air blower are one of the type of industrial centrifugal air blowers. We are manufacturer of didw blowers in Ahmedabad, Gujarat, India
Where you need more volume of air, you need didw blowers. Didw blower is low pressure air blower. There are various types of didw centrifugal fan like didw backward curved fan, didw forward curved fan, didw type fan, didw type blower system, etc.
What is Centrifugal Air Blower Specification:
To move air in ventilation or exhaust system, energy is required to overcome the system losses. The energy can be in the form of natural convection or buoyancy. Most systems require some powered air-moving device such as a fan or ejectors. Fans are the primary air moving devices used in industrial applications.
Application of Industrial Blower Fan Manufacturer:
A wide range of industries chemical, petrochemical, iron, steel, pulp, paper, plastic, glass, hotel, hospital, power plants, refineries, fertilizer units, nuclear power plants, pharmaceuticals, textiles, atomic energy and heavy eater plants utilities the fans for air and pressure application.
Centrifugal Air Blower Working Principle:
For the working medium as air is sucked from atmosphere, due to suction create at the impeller eye as a result of rotating impeller. The air is accelerated in the inlet pipe due to the flow acceleration in the fan’s inlet part the velocity is increase and thus pressure and temperature decreases.
The impeller is rotated and thus each particle of fluid passing through the impeller is accelerated and thus kinetic energy increases. The impeller blades are such that the cross sectional area between two blades increases from inlet to outlet of impeller.
Air moving devices can be divided into two basic classifications: ejectors and fans ejectors have low operating efficiencies and are used only for special material handling applications ejectors sometimes are used when it is not desirable to have contaminated air pass directly through the air-moving device. Ejectors are utilized for air streams containing corrosive, flammable, explosive, hot or sticky materials that might damage a fan ejectors may also be used in pneumatic conveying system.
Centrifugal Air Blower Applications:
The range of fans, blowers and exhausters offer high performance units that are both flexible and compact. This heavy duty, high quality units are suitable for a variety of industrial applications which include
- Drying process
- Heat exchanger
- Pneumatic devices
- Handling hot and corrosive gases
- Air Sampling
- Combustion Air
- Vacuum Lifting & Holding
Centrifugal Air Blower Specification:
The principle parts of any fan are the impeller and the housing
The impeller is a rotating element that transfers energy to the fluid. The blades are the principle working surfaces of the impeller. Flange/inlet plate may be used to support the blades. Hubs may be used to support the blades directly or through a flange through the shaft.
The housing is the stationary element that guided the air or gas before and after the impeller centrifugal housing components include the side sheets and scroll sheets. The point of closers approach to the wheel is cut off. The area over the cutoff is called the blast area. Axial housing components include the outlet cylinders, the inner cylinder, the belt fairing, the guide vanes and the tailpiece.
The inlet is the opening through which air enters the fan. A stationary inlet piece can be called an inlet cone, an inlet bell, inlet nozzle or a venture. The outlet is the opening through which air leaves the fan.
A diffuser can be provided to transform kinetic energy to pressure energy. When a diffuser is supplied with the fan, the exit opening of the diffuser becomes the outlet of the fan.
An inlet box may be used to provide side entry or a means of keeping the bearing out of the air stream. When an inlet box is provided with the fan, the opening to that box becomes the input of the fan
Stationary vanes may be used to guide the flow. Vanes used upstream of the impeller can be called inlet guide vanes. Vanes used downstream of the impeller can be called discharge guide vanes.
The fan may also be equipped with as own shaft and bearings the bearing may be supported on or within the housing.
Centrifugal Air Blower Accessories:
Most frequently requested accessories include:
Dampers & Variable Inlet Vane assemblies: Robust in design and manually or mechanically actuated to accurately control fan performance.
Noise Attenuators: Designed to reduce noise on fan inlet or discharge where specific noise criteria must be met.
Anti-Vibration Mounts & Flexible Connections: Spring or rubber-in-shear mounts. Selected to minimize vibration transmission to structures and ducts.
Casing lagging and cladding: For acoustic and high temperature applications.
Mesh safety guards: Inlet and discharge guards where no ducting is connected.
Inlet Box: Designed to replace performance reducing elbows on fan inlets.
Vortex: Specifically designed to reduce velocity on the fan discharge, thus improving performance.
Shaft Seals: Rubbing type or mechanical, tailored for individual applications whether it be for noise reduction or gas containment.
Anti-Spark Construction: Where increased safety is required for explosive / flammable gasses or dust.
Split Casings: For ease of maintenance / impeller and shaft removal.
Air Filters: Where the air supplied to an application must be ‘clean’.
All fan accessories are attributed to the extensive care in design and manufacture.
Types of Centrifugal Blower Impellers:
The BK impeller has swept back wings. They are highly efficient and have a “non-overload” characteristic. The power consumption curve is flat in the normal operating range and drops as it approaches free exhaust. The type is not suitable for air/gas with impurities/dust content.
The TR impeller has straight, radial wings that are open, without a front plate. The impeller is self-cleaning and counteracts dust deposits on the wings. The power consumption curve rises as it approaches the free exhaust. The efficiency is relatively low. The type is suitable for air/gas containing dust and for pneumatic conveyor systems.
The TRL impeller has the same profile as the TR impeller but has a front plate which improves efficiency. The impeller is suitable for use at high temperatures.
The BF impeller has swept-back wings which are curved slightly forward, with an almost radial outlet direction. Efficiency is high and the power consumption curve is favorable. The impeller is of the so-called “self-cleaning” type and is ideal for air/gas with partial dust content. The type is particularly suitable for flue gases and larger areas.
Centrifugal Fan Blower Impeller:
Impeller mounted directly on motor shaft journal
This arrangement is a compact, reasonable design and requires no transmission journal. However, it must not be used for gas temperatures of over 80°C, places a high load on the front motor bearings, leaves little space for a packing box and has a fixed speed (unless a frequency transformer is used).
Impeller mounted between the shaft bearings
This arrangement has a stable, robust design, requires no transmission journal and resists high temperatures. It is designed for the very largest fans and has plenty of space for packing box/cooling plates and auxiliary drives. However, it has an expensive shaft, requires demanding design work, a suction box, two packing boxes and an expensive fan and has a fixed speed (unless a frequency transformer is used).
Impeller mounted on free shaft journal – belt drive
This arrangement allows the possibility of varying the fan speed by changing the pulley. Plenty of space is supplied for the packing box/cooling plate and it has a good arrangement in a confined space. However, the transmission journal is belt drive and the shaft must be specially designed if the diameter must be increased, if large motors are used and if the belt forces are high. Also, it requires more maintenance in terms of adjustment/tightening the belt drive and is relatively large.
Impeller mounted on free shaft journal – belt drive on oblique pendulum
This arrangement allows the possibility of varying the fan speed by replacing the pulley and provides plenty of space for the packing box/cooling plate. However, the transmission journal is belt drive and the shaft must be specially designed and the diameter increased, if necessary, by using large motors and high belt forces. Also, it requires more maintenance in terms of adjustment/tightening of belt drive.
Impeller mounted on free shaft journal – direct drive through clutch
This arrangement features a stable, robust design, no transmission journal, resistance to high temperatures and plenty of spaces for packing box/cooling plate. However, it is relatively large and operates at a fixed speed (unless a frequency transformer is used).
Centrifugal Fan Working Operation:
The centrifugal fan is a radial flow machine which produces the necessary pressure to move gas by the centrifugal force built up inside the fan casing. The design of the fan blade has a primary influence on performance.
These types of fans are usually employed for ventilating duties requiring a somewhat higher delivery pressure than that available from axial fans.
The centrifugal fans can efficiently move large or small quantity of air over a greater range of operating pressures. All centrifugal fans have an impeller or wheel mounted in a scroll type of housing, as shown. The impeller is turned either by the direct drive or more frequently by an electric motor employing pulleys and belts. The centrifugal force created by the rotating impeller moves the air outward along the blade channels. The outward moving air stream is combined by the scroll into a single large air stream. These air streams leave the fan through the discharge outlet. Centrifugal fans are available in direct drive, direct coupled and vee belt drive configurations. Variations in these configurations are available in order to suit exact installation conditions.
Centrifugal Fan Applications:
Due to the enormous variance in fan applications, fans from a vast array of materials such as:
- Mild steel.
- Stainless steel.
- High nickel alloys.
- Specialized coatings are also available to suit client specifications.
An extensive list of accessories is available for all centrifugal fans
- Noise attenuators.
- Multi-leaf dampers.
- Variable inlet vanes.
- Actuators and positioners.
- Anti-vibration mounts.
For smaller applications, forward curve multivane fans and pressed construction high pressure fans in both mild and stainless steel. As most parts are off-the-shelf, speedy deliveries can be affected for these economical fans.
On the basis of the pressure, we can classify centrifugal fans as follows:
- High pressure centrifugal fan
- Medium pressure centrifugal fan
- Low pressure centrifugal fan
High-Pressure centrifugal fans:
High-pressure centrifugal fans are ideal for situations involving temporary wet grain holding, deep storage, or wherever high static pressures are required.
Ten gauge or heavier steel housings and non-overloading, vibration-proof fan wheels make fans tough. And when these features are combined with low power consumption and ample air delivery, the result is low cost, efficient aeration for almost any application.
- Fan wheels are assembled with chuck bolts and / or welds to prevent loosening, and are statically and dynamically balanced for smooth, trouble-free operation.
- Fan wheels are direct connected to motor shafts to eliminate belt fatigue and drive failure problems
- Taper-lock bushings are used to secure fan wheels to motor shafts – so fan wheel removal is simplified.
- Flanged outlets and extended inlet collars provide strong connections and simple installation.
Specially-designed inlet cones improve fan performance by providing smoother inlet air flow for steady, even air delivery.
Medium-pressure centrifugal fans
In this series, centrifugal fans are designed with large diameter fan wheels and low speed motors to provide high volumes of air at lower static pressures, while keeping operating noise to a minimum. These fans feature the same rugged construction and exacting specifications as the high-pressure units described above.
Low pressure centrifugal fan:
Similarly to close-coupled pumping units, the fan impeller is fitted directly on the shaft of the motor mounted on a base which is cast in iron or fabricated as a welded steel structure. As a whole the design is very compact.