Industrial Fans And Its Applications

Neel Rao

Industrial fans are machines which are driven by a motor or turbine which provides energy to the rotor by rotating a shaft and causes rotation of a number of blades. These blades are connected to a hub and shaft that generate a pressure to move air (or gases). This air is moved against resistance caused by ducts, dampers, or other components in a fan system.

Industrial fans or industrial process fans as the name suggests are the fans which are responsible for many functions in the industries. Providing and accommodating a large flow of air or gas to various parts of industries is the primary function of the process fans. Its secondary applications range from material handling, boilers, refrigeration, dust collection, cooling applications, exhaust systems, drying ovens, high-pressure applications including HVAC systems, low-pressure HVAC, air-circulation, clean and dust-laden air/gases, moist air/gases to ventilation and many more.

Usage of energy by industrial fans per year is estimated at over 78 billion kilowatt-hours.

For maintaining fan’s performance levels, their regular maintenance is important which includes periodic inspection of all system components, bearing lubrication and replacement, belt-tightening and replacement, motor repair or replacement and fan cleaning.

As far as the efficiency of centrifugal fans is concerned, each type of fan has a different peak efficiency range, such as given below:

Centrifugal Fan:

  • Air foil, backward curved/inclined: 79-83.
  • Modified radial: 72-79.
  • Radial: 69-75.
  • Pressure blower: 58-68.
  • Forward curve: 60-65.

The system resistance curve and fan curve intersect at a point on which the fan operates. The system resistance plays a vital role in evaluating the efficiency and performance of the fan. Depending on the process, the system resistance also changes. Hence, for efficient operation of the fan system, system resistance has to be checked periodically.

It is important to select type of fan, motor and control system that avoids equipment overloads when the actual air flow in a system cannot be predicted with accuracy, or the flow of air is expected to vary considerably.

While selecting a fan, the use of “systems approach” will typically yield a quitter, more efficient and more reliable system by optimizing the energy performance of fans. Proper selection of fan type and size will require precise determination of air-flow and required outlet pressure. Other than these important considerations for selecting a fan are noise, rotational speed, air stream characteristics, temperature range, and variations in operating conditions, space constraints, system layout, purchase costs, operating costs and operating life.

To handle the largest expected operating or design conditions, fans are sized accordingly. In order to reduce energy consumption and extend fan and motor life, there is a need for efficient flow control in situations where oversized equipment is used over an extended period of time. Proper observation of performance and behaviour of the system is advisable. Further, regular maintenance not only reduces the energy and repair costs but also can increase reliability and service life.

Industrial fans are critical for process support, human health and to keep industrial processes working. It supports many functions in a variety of industries and a fan failure will immediately cause a process to stop. Process fans aid in improving worker productivity and product quality. Hence, industrial fan reliability is important for industries.