Fans are used in several industries and applications to move air for heat transfer, (such as convection cooling and heating), air exchange (such as ventilation and exhaust) or filtration. They typically consist of a moving element like blades or vanes, connected through a shaft to a motor that drives the fan. Fans are categorized according to the type of blade, the direction of air travel and the type of motor it uses. There are different types of fans for different applications, with fan blade configuration affecting air pressure and velocity.

Types of fans

There are two types of fans: axial and centrifugal. Axial fans move air parallel to the axis of the fan rotation, whereas centrifugal fans move the air in a direction that is perpendicular to the axis of rotation. Each type of fan has certain characteristics that relate fan air flow rate to static pressure. It is therefore important to understand the effects of fan blade design on these characteristics to select an appropriate fan for a specific application.

Axial fans

Axial fans have blades that look like propellers that can be forward-swept or backward-swept (Figure 1). The performance of these fans can vary widely depending on blade width and shape, the number of blades and the rotational speed. In general, axial fans can generate a large amount of air flow with a small pressure gain with high efficiency.

Axial fans are well suited for low-resistance, high flow applications such as building ventilation, green energy applications such as wind turbines, electronic system cooling, automotive climate control and refrigeration.

Pelonis offers a wide variety of models of axial fans that meet demanding performance requirements for static pressure, efficiency airflow and noise. These fans are RoHS compliant and are available to customers in various voltages in accordance with international standards.

Figure 1. Axial fan. Source: Pelonis Technologies, Inc.

Centrifugal fans

Centrifugal fans receive air parallel to the axis of rotation but expel the air perpendicular to the axis of rotation through a housing (Figure 2). This housing – or cowl – allows the air to be pointed toward a specific target area for more effective cooling. Centrifugal fans are well-suited for applications that require a high volumetric air flow or high air pressure. The blades in centrifugal fans can be forward-curved or backward-curved.

Forward-curved fans have a large number of shallow blades that point toward the direction of spin. They are well-suited for residential HVAC systems such as air conditioning units and furnaces, electronics cooling applications, air purification, humidification and dehumidification as well as general building HVAC. Backward-curved fans have a fewer number of longer blades that point away from the direction of spin. They are used in several different applications such as data server cooling, industrial equipment where high airflows and pressures are needed, HVAC systems and semiconductor clean rooms.

A system design engineer would select the type and design of a centrifugal fan based on the desired fan motor size, operational speed, pressure requirement, noise and efficiency. Pelonis’s backward-curved fans are characterized by high efficiency, high cubic feet per minute and rugged long-life construction for high static pressure applications.

Figure 1. Axial fan. Source: Pelonis Technologies, Inc.

Pelonis Technologies

The experts at Pelonis Technologies have the knowledge and skills to answer questions and find the product that suits customer needs. With over 25 years of product development and manufacturing experience, Pelonis Technologies' management team and engineers are committed to providing exceptional quality, product innovation and service at competitive pricing. Pelonis’ passion is to improve existing products and develop new applications that benefit customers and their ever-changing needs. This dedication has enabled Pelonis Technologies to build long-term partnerships with global customers. Valued customers come from a variety of sectors, including medical equipment, aerospace and defense, heating and air-conditioning, automotive and appliances. More information about Pelonis and their fan technology can be found on the Pelonis Technologies website.