Fans are primary components to many thermal management systems. Proper thermal management to maintain temperature and cool equipment in both indoor and outdoor applications is necessary for optimizing system performance, increasing machine or system uptime, extending operating life and reducing field maintenance time and costs. Used for direct cooling and airflow to dissipate heat from a heatsink, power supply or PC board, fans must be able to efficiently operate in a wide variety of applications. This ranges from traditional applications like control cabinets and electronic enclosures, building automation and telecom systems, and outdoor kiosks to emerging applications including alternative energy and electric vehicles. Many of these applications require fans with filtering capability to protect electronics and offer low pressure drop, water resistance, even fire protection, and the ability to capture large amounts of airborne dust. Louvered filter fan kits, louvered fan guards, and filters deliver superior protection compared to regular grills or guards often used with fans, because they provide ingress protection for the fan blades.
Louvered fan guards are a safety mechanism that provide protection against accidental contact with the fan blades, by fingers or other unwanted objects. Louvered filter fan kits are specifically designed to filter and prevent foreign objects such as dust, dirt, and moisture from entering cabinets and enclosures. For example, cooling and protecting a typical industrial cabinet or enclosure installation may require a fan and an additional filter guard or even two fans. Depending on the type and number of components inside the cabinet and their location, one intake fan could be installed at the top or bottom of the enclosure to bring in cooler ambient fresh air. A second filter guard may be installed at the exhaust location to remove the ambient air that was heated by the components inside the cabinet. The intake is generally installed at the bottom of the cabinet, and the exhaust near the top of the cabinet, to take advantage of naturally-occurring convection (Figure 1). For additional air filtering, and to protect internal components, louvered filter fan kits are the best option for demanding applications typically found in industrial and automation environments.
Figure 1: Typical two-fan cabinet installation locations. (Image source: Orion Fans)
Figure 2: Examples of a two-fan cabinet installation (left) and a one-fan, one-filter guard cabinet installation (right). (Image source: Orion Fans)
Louvered filter fan kits
Louvered filter fan kits contain all of the necessary components for industrial applications, including the fan, louvered fan guard, filter, metal guard, and hardware. The kits come fully assembled in order to simplify the installation process. Louvered filter fan kits are available for a wide range of fan sizes and can be combined with harsh environment fans to provide additional protection for industrial and marine applications. Harsh Environment fans can be combined with a Louvered filter fan kit to provide IP55, IP56, IP68, and even salt-fog protection. Louvered filter fan kits with EC fans are now available with IP68 rating and ATEX certification for use in Zone 2 equipment. These filter fan kits eliminate the possibility of an explosion or fire in applications with explosive atmospheres or flammable gases.
Figure 3: Examples of snap-on, sliding, and hinged louvered fan kits. (Image source: Orion Fans)
Fans exposed to excessive amounts of heat and dirt fail at a rate much greater than those operating in normal environmental conditions. A dirty air filter can damage the fan motor by blocking the airflow, causing the internal motor temperature to rise. A fan motor operating above the ideal design temperature will cause the bearing to rapidly lose its lubricating properties, overheat and fail prematurely. Harsh Environment fans and accessories are designed and tested to perform in the toughest conditions and protect against dust, moisture, salt fog, salt spray, temperature changes, humidity, and more. When combined with a louvered filter fan kit, IP ratings and protection levels increase, making this solution even more important for industrial applications where system or machine uptime is critical. For example, certain fan models have NEMA insulation ratings of either Class B (for PBT plastic fans) or Class F (for metal fans), allowing for higher fan operating temperatures. When combined with a louvered filter fan kit, the NEMA ratings are preserved providing maximum protection for the installation.
Works with AC, EC, or DC
Louvered filter fan kits are available with either an AC, EC or DC fan, depending on the application. AC and EC fans typically plug into a wall outlet, while DC (direct current) fans are typically powered by batteries, distributed power supply circuits or rectifiers (which convert alternating current to direct current). The AC filter fan kits are generally available in 115 V, 230 V, and dual voltage 115/230 V. Most EC filter fan kits feature a universal input voltage of 90-265 VAC. Most DC filter fan kits are available in 5 V, 12 V, 24 V, and 48 V. Louvered Filter Fan Kits are available with fans in 80, 92, 120, 172, 180, 200, 225, and 280 mm sizes. The different sized fans and their use are determined by the fan CFM rating and the size and type of enclosure or cabinet, along with the heat load being generated inside the cabinet. Due to the presence of the filter, the rated airflow for fans equipped with a louvered filter fan kit is reduced by approximately 40%. Currently, louvered filter fan kits provide CFM ranges from ~ 67 CFM to ~ 700 CFM.
Louvered fan guards
Louvered fan guards provide protection for the fan unit from fingers and other objects. To accommodate different applications and provide maintenance time savings when changing filter media, louvered fan guards are available in several styles including snap-on, sliding, and hinged versions (Figure 4). Sliding versions feature a push/pull mechanism for easy opening, while hinged versions flip open.
Figure 4: Examples of snap-on, sliding, and hinged louvered fan guards. (Image source: Orion Fans)
The sliding and hinged louvered fan guards are easy to open with no tools required to access the filters. The louvered fan guards vent with screens at a 45-degree angle to combine high levels of protection with the highest airflow possible. These plastic fan guards are flame resistant to UL94V-0 standards and feature UV protection for increased resistance and improved appearance over time. A high-density foam seal is used to provide maximum protection from the elements.
The standard filters provided with a louvered filter fan kit are made of nylon fiber and synthetic resin and can filter down to eight microns.
New reusable specialty filters are available for applications in harsh environments, such as washdowns and oil rigs. Three types of reusable specialty filters are available for equipment where permanent, cleanable filters are most appropriate. These filters are geared for specific applications, where high-density, water-resistant or fire-retardant protection is needed, in addition to the ability to filter airborne dust. When combined with a louvered filter fan kit, these filters provide excellent filtration solutions for industrial equipment, industrial computing, and HVAC and air handling applications. These specialty filters are currently available for use with 120 mm to 280 mm louvered filter fan kits and guards.
Figure 5: Three types of filters are available dependent upon the application. (Image source: Orion Fans)
High-density filters are a foam air filter that deliver a low pressure drop and the ability to capture large amounts of airborne dust in industrial enclosure applications. High-density foam air filters are available in a broad range of porosities (PPI) to meet custom filtration performance requirements. The standard is 45 PPI (5x the protection of normal filter media). The material is an open cell, specifically-engineered polyurethane foam that is fungus resistant and has both UV protection and hydrolytic stability. These filters offer low air flow resistance for use in a wide variety of industrial and outdoor conditions. The filters comply with UL 94 HF-1 self-extinguishing flame safety standards for electronics in industrial, medical, telecom, power generation, and military air filter applications.
Water-resistant filters are a hydrophobic mesh air filter that features a water-repellent, low pressure drop media to reduce ingress of airborne mist and other liquids in harsh environment enclosures. They provide a cost-effective alternative to expensive, more air flow restrictive membrane media. The hydrophobic filter media is a durable, cleanable, moisture-resistant solution for indoor/outdoor cabinets and process equipment requiring mist elimination zones. The hydrophobic mesh will help in meeting various enclosure-level standards such as MIL-STD, NEMA, and IP ratings.
Fire-retardant filters are PyroCide air filters that can be used for industrial and electronics enclosure applications that require stringent flame safety standards. The filters are aluminum honeycomb thermal barriers treated with a heat responsive intumescent flame coating for fire containment in electronics enclosures. The filters are designed with thin profiles and configured with aluminum honeycomb that provides low resistance to airflow.
To extend the operating life of vital electronics, the proper fan and filter must be specified to provide a suitable thermal management solution. Fans are required to meet a wide range of application demands and choosing a filter fan kit that offers the best level of protection from industrial elements and environmental hazards is vital to the performance of the system. Louvered filter fan kits not only offer superior protection from the elements, but with the addition of specialty filters that address volume of contaminants, moisture and fire, they can protect and extend the life of the system or components inside cabinets and enclosures, while simplifying installation, reducing maintenance, and lowering the total cost of operation.