Pressure blowers and fans are used to create and sustain a positive pressure for inflatable structures, clean rooms, laboratories, and medical facilities. Pressurization blowers are fans that create a positive pressure in a sealed or restricted environment. Some pressure blowers and fans are designed for clean air supply applications. Others are designed to handle the corrosive gases used in petrochemical plants and chemical processing operations. Pressure blowers and fans for heavy industrial air streams, erosive gases, and air streams with particulates are also available. Pneumatic blowers are used to move granular materials such as grain, pellets, and powders, as well as particulate matter such as soot, contaminants, and light solids. Pressure blowers and fans that are designed to exhaust smoke are also available.

Parameters

Parameters for pressure blowers and fans include system and style. There are two types of systems: bare and packaged. Bare fans blowers include components such as fan blades, bearings, mountings, and enclosures. They require a power system and a user-provided control system, however. Package pressure blowers and fans are complete systems. These full-functional products only require electricity or a similar power source for operation. In addition to system, there are two choices for style: forced draft and induced draft. Forced draft refers to the movement of air under pressure. Forced draft fans and blowers are so named because they "force" air to move. Induced draft refers to the movement of air by means of an induced partial vacuum.  

Selection

Selecting pressure blowers and fans requires an analysis of performance specifications and materials of construction. Air flow rate is the rate at which air moves within or between zones. Static pressure is the pressure that exists when an equal amount of air is supplied to and exhausted from a space. Media temperature is expressed as a range. The diameter of the fan, or the diameter or maximum dimension of the blower outlet is also an important parameter to consider when selecting products. Materials of construction for pressure blowers and fans include aluminum, cast iron, steel, stainless steel, plastics, and composite materials. 

Specifications

Pressure blowers and fans carry three types of specifications for fan or blower type: design configuration, drive options, and fan or blower class. There are three choices for design configuration: axial, bi-lobal or tri-lobal, and centrifugal. There are two drive options: direct drive and belt drive. Fan or blower class refers to a numeric value that describes the device’s compliance with requirements from the Air Movement and Control Association (AMCA). Typically, pressure blowers and fans with a larger class number provide greater minimum performance but cost more.