插上气瓶，随时补气Cylinders in a bank, gas on demand

瓶组是燃气系统里最“重”的一段：22 MPa 储气、数百公斤到数吨的整组重量、以及一旦泄漏就不可逆的后果。规格从 8 瓶位的点供小站，到 88 瓶位的大容量储气单元，单瓶水容积常用 205 L，24 瓶位对应总容积 4920 L。瓶组本体由无缝钢瓶、汇流排、进出气阀组、安全放散与压力表组成，瓶与瓶之间通过高压汇流管并联，任一瓶可单独切出更换。From 8-position point-supply banks to 88-position bulk storage, typically 205 L per cylinder; 24 positions total 4920 L. Each cylinder can be isolated.

固定瓶组落地浇筑基础并设围栏与放散口；需要周转的场合做成集装格，工作压力 15 MPa，配吊装框架，可直接上货车或置于用气点旁。选型时真正需要确认的是三件事：调峰时段需要多少储气量、场地允许的瓶组尺寸、以及充装端接口与本站是否一致。Fixed banks on a concrete base; transportable frames at 15 MPa with lifting frames. Selection turns on required storage volume, footprint and filling interface.

CNG 储气瓶组是把压缩天然气存在一串无缝钢瓶（或钢制大容积容器）里，通常 25 MPa 设计压力。它本身不产气，作用有两个：调峰——用气高峰时补足减压撬来不及供的那部分；缓冲——让压缩机或槽车不必频繁启停。A CNG bank stores compressed gas in a string of seamless cylinders or large steel vessels, typically rated 25 MPa. It produces nothing itself; it shaves peaks by covering what the skid cannot supply instantaneously, and buffers the compressor or trailer against short cycling.

取气顺序是有讲究的：先取高压瓶、再取中压瓶、最后取低压瓶。这样出口压力下降平缓，减压撬进口不会突然“见底”。如果所有瓶并联同时取，压力会一起掉，末端设备容易低圧报警。工程上通过分组阀与顺序控制实现，简单的站也可以靠手动分组阀。Draw-off order matters: high-pressure group first, then medium, then low. Outlet pressure then falls gradually and the skid inlet never collapses. Drawing the whole bank in parallel drops every cylinder together and trips low-pressure alarms downstream. Group valves and sequencing provide the order; small stations do it manually.

充装侧同理：先充低压组、再充高压组，可以缩短充装时间并降低压缩机负荷。瓶组还配有排污阀、安全阀（或爆破片）与压力表，这些附件的可靠性直接决定瓶组能不能长期安全使用。Filling runs the other way — low group first — which shortens fill time and cuts compressor load. Each bank carries drain valves, safety valves or bursting discs and pressure gauges; their reliability decides whether the bank stays safe for its whole life.