No power ventilation 1. Use of natural air convection principle, any parallel to the direction of air flow, accelerated into the bottom-up vertical air flow. (2) use of construction and equipment combined with the chimney effect itself, in order to achieve the indoor and outdoor ventilation equipment. 
 The Liaocheng sun Stainless Steel Co., Ltd. specializing in the production of free power - roof ventilation products, with more than 20 sets of large and medium-sized stamping equipment. With ventilators researchers, more than 160 product models, 200, 300, 400, 500, 600, 680, 800, 880, and all kinds of special-shaped ventilation, has a professional installer. Welcome customers counterparts at home and abroad visit the guide. 
 In recent years, under the joint efforts of the company engineering and technical personnel, factory production of free power - roof ventilation domestic specifications, the largest and most complete variety of manufacturers. 300, 360, 450 is mainly used for residential buildings, the floor of the villa roof ventilation mouth, 500, 600, 680 is mainly used for factory workshop and large public places ventilation exhaust. Full stainless steel body, cast aluminum support a special double-sealed bearings. The products sell all over the surface of the country, first class after-sales service.