Theophilus van Kannel invented the revolving door and patented it in 1988. The revolving door prevented baleful miasmas and foul smelling and harmful things entering a building. Air curtain was van Kannel's sophomore inventing effort and he patented it in 1904. An air curtain was installed in a building for the very first time in 1916.
What Does An Air Curtain Do?
In simple terms, an air curtain blows down a stream of air continuously from the top a doorway that is open to its bottom. It is generally used to form the second line of defence inside closed doors or to replace the plastic flaps that are hung in front of open doorways. The barrier formed by air curtains allows movement of people and products, but not movement of air.
In fact, air curtains perform two functions. First of all they provide insulation. Air's insulating power is quite well known. A layer of air that is trapped between window panes keeps heat away. Secondly, the air curtain can be used as a backup on the interior side of a door so as to prevent outside air from entering the room and keep insects and pollutants away.
Industrial applications of air curtains include preventing outside air influx through openings into cooled or heated areas. Typically, they are used for receiving and shipping doors in warehouses and doors between areas in factories where different temperatures are to be maintained. Special applications include fresh air control, oven humidity and dust control, prevention of over spray from paint booths drifting into other areas, etc.
Air curtains are used in hard rock mines at 1,100 feet depth in order to control fresh air flow introduced into them. Commercial buildings use air curtains at entrances in order to reduce energy consumption as well as for providing comfort. In the winter season, they retain the warmth inside by preventing cold air influx. It is possible to augment an air curtain with an electric heater so that they provide a stream of hot air. In the summer season, they are helpful in keeping the hot humid air away and preventing the escape of air conditioning.
Summarizing, air curtain systems provide a great deal of benefits over their long life span. These benefits definitely pay off your investment on the system back many times over. The benefits include increased employee comfort and hence improved productivity, energy savings through climate control, faster as well as safer flow of traffic, increased production because of open and clear open doorways, savings in cost due to lower breakdowns and door maintenance, availability of more usable space near doors, elimination of fog and ice in cold storage spaces and better safety because of improved visibility in door areas.