Fan is a machine which raises gas pressure and discharges gas by incoming mechanical energy. It is a kind of driven fluid machinery. Fan is the routine abbreviation of gas compression and gas conveying machinery in China. The so-called fans include ventilator, blower and wind driven generator. Fans are widely used in all sectors of national economy such as metallurgy, petrifaction, force, urban rail transit, textile, vessel, etc. and in ventilation at all kinds of places. Except for traditional application areas, fans are widely used in ventilation, dust discharge and cooling of factories, mines, tunnel, cooling wall, vehicle, vessel and buildings, in ventilation and inducing air of boiler and industrial kiln, in cooling and ventilation of air conditioning equipment and household electrical appliances, in drying and sending of grain, in air inflation and advance of wind tunnel, wind generator and hovercraft, and so on.
In early operation of fans, bearing has small vibration, but as time flies, dust within fans will not adhere to impeller evenly, will break dynamic balance gradually, and increase bearing vibration bit by bit. Once vibration reaches the biggest permissible value at 11mm/s, fans must be turned off and repaired (clear dirt retention and recover dynamic balance). Therefore, users cannot use fans at that dangerous time. When fan vibration is close to dangerous value, vibration measuring instrument will give an alarm. So, fan vibration isolators must be used, and it is extremely urgent to find proper ones for installation and usage.
How to select fan vibration isolators? Spring shock absorber, rubber shock absorber and air-cushion shock absorber are generally used in fans damping. The following are the performance of the three shock absorbers. In aspect of cost, the air-cushion shock absorber is the most expensive, the spring one takes the second place while the rubber one is the cheapest. In aspect of vibration reducing performance, the air-cushion shock absorber has the best performance, the spring one takes the second place, and the rubber the lowest. In aspect of service life, the combined life of spring shock absorber is the longest for 15 to 20 years, the air-cushion takes the second place, and the rubber the shortest. According to the different materials used by factories, shock absorbers are used in different environment. In aspect of easy maintenance, spring shock absorbers rarely need maintenance during service life, while air-cushion ones shall be repaired once for one to two years. In general, spring shock absorbers are suitable for fans.
