1·In case that the well producing lots of air we recommend to add air release valve.
假如水井从地底吸收气体，则表明其深度不够。假如水井产生大量气体，我们建议增设排气阀。
2·VENT GUARD? Is a protective enclosure designed exclusively for the air release valve found in many public water supply systems.
通风口的保护外壳设计，专用于许多公用水供应系统中的空气释放阀。