Qingzhou Hengyuan Temperature- Controlled Equipment Co.,Ltd. is a leading manufacturer specializes in manufacturing : 1) Ventilation cooling system,such as large-scale poultry fan,large scale fan for greenhouse and factory buildings,negative pressure fan,circulation fan,unpowered roof fan 2)Cooling humidification system,such as cooling pad 3)heating system, such as automatic coal(fuel,electric,gas)heater 4)Manure cleaning system : manure cleaning machine.