Paul Smith, Head of OEM at Axair Fans, explains how EC plug fans are the preferred solution where constant volume and pressure are required.
High-performance ventilation systems such as air handling units, containment or cleanrooms, ensure consistent, clean air with a high air exchange rate and the correct measure of pressure, temperature and humidity. In applications like pharmaceutical manufacturing, even the smallest contaminated particle can affect finished products. Therefore, it is vital for patient safety and company reputation that manufacturers are compliant with good practices and adhere to the guidelines for ventilation systems and fan specification.
The ventilation system and industrial plug fan specification are determined by considering the individual characteristics of each cleanroom set-up. This could include the number of contaminants that are likely to be produced, the size of the particles that need to be filtered and the airflow and pressure required to remove and purify the air. The size of the room will depend on the equipment needed and the number of processes required. There are other fan selection criteria, but that’s for another time, so for now, we’ll focus on the fan filter unit and the specific type of fan that’s preferred.
Compact air handling
The fan filter unit (FFU) is the most popular choice for containment ventilation providers and serves to generate a uniform, particle-free airflow in a cleanroom. FFUs allow smaller air handling units to be specified for a particular cleanroom installation, saving time and cost.
FFUs have been a popular choice in the containment industry since they were first introduced in 1984. The technology behind it is simply a HEPA filter attached to a high-performance EC Plug Fan, offering low noise and efficient filtration to cleanrooms. The GKHM range of EC modular plug fans from Axair, for example, are energy efficient and enable more compact air handling. A popular choice with the air handling and containment market leaders. EC backward curved centrifugal fans develop pressure within the envelope of the impeller and do not, therefore, rely on a scroll housing for this purpose. They are relatively low cost and can be simply and cheaply housed and built into finished units. Air is drawn through a radius inlet ring, which minimises pressure losses and air leakage, and is discharged at 90° to the inlet axis. The impeller has a ‘non-overloading’ characteristic in that it draws maximum power near the centre of its pressure/volume flow curve. In applications where airflow and pressure are vital, these high pressure backward curved fans will generate the airflow required and will work against the increasing resistances of any filters to deliver a constant volume of air due to the electronic computation of the EC motor. This allows the user to program the exact airflow and pressure requirements into the system. A sensor then works to constantly monitor the output and adjusts accordingly.
With reductions in operating noise, low running costs and high-efficiency filtration that is easy to maintain, the EC plug fan is the perfect solution for maintaining a clean, safe, and cost-effective cleanroom or other air handling applications. Cleanrooms operate continuously and therefore tend to have high running costs, so the significant energy savings soon return the initial capital outlay for incorporating energy-efficient plug type fans. The option of speed control allows for slowing down the fan filter unit when not in use to reduce power consumption and improve the life of the motor and filters.
There are many manufacturers of EC plug fans, but with the pressure of Brexit, continuing economic issues and increases in material costs, inventory has become an issue in the marketplace. Axair has a strong inventory and stock delivery schedule in place.
