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Schematic of underground mine ventilation The mine ventilation fan, before 1908. Underground mine ventilation provides a flow of air to the underground workers of a mine with sufficient volume to dilute and remove dust and noxious gases (typically NO x, SO 2, methane, CO 2 and CO) and to regulate temperature.
A heat gun comprises a source of heat, usually an electrically heated element or a propane/liquified petroleum gas, a mechanism to move the hot air such as an electric fan, unless gas pressure is sufficient; a nozzle to direct the air, which may be a simple tube pointing in one direction, or specially shaped for purposes such as concentrating the heat on a small area or thawing a pipe but not ...
Diagramatic operation of a thermal wheel Ljungström Air Preheater by Swedish engineer Fredrik Ljungström (1875–1964). A thermal wheel, also known as a rotary heat exchanger, or rotary air-to-air enthalpy wheel, energy recovery wheel, or heat recovery wheel, is a type of energy recovery heat exchanger positioned within the supply and exhaust air streams of air-handling units or rooftop ...
The original centrifugal fan designs were bought from a company HSM (Heinke-Schuitema-Musselkanaal) located in the town of Musselkanaal in 1936. Throughout the history the program of centrifugal fans [25] [26] [27] has been extended with various models, including ATEX fans for use in hazardous environments. ATEX centrifugal fan units are built ...
A centrifugal fan is a mechanical device for moving air or other gases in a direction at an angle to the incoming fluid. Centrifugal fans often contain a ducted housing to direct outgoing air in a specific direction or across a heat sink; such a fan is also called a blower, blower fan, or squirrel-cage fan (because it looks like a hamster wheel).
The axial fan is often contained within a short section of cylindrical ductwork, to which inlet and outlet ducting can be connected. Axial fan types have fan wheels with diameters that usually range from less than a foot (0.3 meters) to over 30 feet (9.1 m), although axial cooling tower fan wheels may exceed 82 feet (25 m) in diameter.
Mechanical ventilation is often provided by equipment that is also used to heat and cool a space. Natural ventilation is the intentional passive flow of outdoor air into a building through planned openings (such as louvers, doors, and windows). Natural ventilation does not require mechanical systems to move outdoor air.
The air column from a 3-foot-diameter (0.91 m) fan, therefore, has more than six times as much friction interface per volume of air moved as does the air column from a 20-foot-diameter (6.1 m) fan. [8] When the down column of air from an HVLS fan reaches the floor, the air turns in the horizontal direction away from the column in all directions.