We are manufacturer of motors and ventilation fan establish on 2003,we have been provided Negative Pressure Ventilation system design services many years now.The Negative Pressure Ventilation design contain the speed of air flow per second and number of air change per hour inside the building.Negative Pressure Ventilation system can be widly used for example chickenhouse,green house,indurstrial plants,storage etc.There are many our competitors motors brouhgt from supplier so they cannot control quality by self,but we all of fan motors supplied by our manufactury. The theory of air exchange and air distribution remove odor and stagnant air out of the house,and hung in windows or doorways to brings fresh air in.The speed of air flow per second,number of air chenge per hour,the amount of fresh air to be brought in can be accurately controlled.ApplicationApplicable to any place,especially the one with poor ventilation the generates heat,waste gas,soot and dust easily,which can achieve at least 95% imporvemeEffect: 95% 1. We use power exhaust coercively to cause air convection to reduce the dust and heat inside the factories.2. After installment, air convection can improve the quality of atmosphere and lower the temperature inside as outside, even lower than outside. Besides, workers can also feel the wind floating. Furthermore, any places can have electricity-saving gear.3. Especially, the places which are easier to bring dust, oil mist, waste gas, and heat can be improved over 95%.Rooftop Extraction FanEffect: 15% 1. They use rooftop extraction fan to exhaust the heat from the factory.2. After installment, only the heat of the roof (up side of the factory) can be improved, but people active section (the down side of the factory) cannot.Positive Pressure Relay FanEffect: 10% 1. They use fan to blowing forward one by one2. After installment, the heat cannot exhaust from the factory entirely, resulting in heated circulation, only can improve the muggy situation temporarilyVortical Ventilation FanEffect: 5% 1. They use an axiom of rising hot air and natural airstream reversing ball to exhaust the heat from the factory.2. The axiom is right but the effect is extremely bad. So many customers regret after installing the fan.At present,our products articles have Ventilation fan,exhaust fan,protable fan,environmentally friendly air cooler for customers needs.We also have offer OEM and ODM services for customer request.