Most compressed gas cylinders require the installation of at least one valve. This valve allows the cylinder to contain gases and allows gas to be filled into or emptied from the cylinder. The cylinder valve is the most vulnerable part of the compressed gas package and requires a thorough understanding in order to maximize its performance. There are three basic valves used in the compressed gas industry. They are the pressure seal valve, the packed valve, and the diaphragm valve. There are several versions or designs within each of the three basic types. This pamphlet will address the more common valves in today’s industry. 大多数压缩气体钢瓶要求安装至少一个阀门。这个阀门使钢瓶可以容纳气体，允许气体灌装进或提取出钢瓶。钢瓶阀门是压缩气体包装的最脆弱的部分。为了最大程度发挥它的作用，要求彻底地理解阀门。在压缩气体工业中有三种基本的阀门。它们是压力密封阀、衬垫阀和隔膜阀。三个基本类型中地每一个还有几个版本或设计。本手册将介绍当代工业中最常用的阀门。 .............................................