香艳h肉辣文各种姿势快穿_男人和女人爽爽爽免费app_亚洲精品中文字幕在线_免费网站在线播放

八、 According to the furnace flue gas pressure

1. Negative pressure boiler: the furnace pressure maintains negative pressure, there is a delivery and induced draft fan, which is the main type of coal-fired boiler; 2. Micro-positive pressure boiler: the furnace pressure is 2-5KPa, no need for induced draft fan, easy to low-oxygen combustion.