The piping between the storage tanks and a Stage III vapor recovery unit is not just plumbing; it is the ductwork that decides how hard the unit has to work. Long paths, sharp bends and forgotten low points each add resistance or collect liquid, and the symptoms appear later as cycling complaints the station cannot explain. Layout discipline at design time prevents all three.
Keep the Vapor Path Short
Every meter of pipe between tank vent manifold and unit inlet adds friction and volume the unit must move. Route the line the shortest practical way around structure rather than the most convenient way for the installer, and size the header for the combined vent flow rather than a single tank. Short paths also mean less pipe to slope, insulate and inspect for the life of the station.
Bend Radii and Fitting Count
Each elbow adds resistance the vacuum pump pays for every cycle. Where the route must turn, use the gentlest fitting the layout allows and count fittings during design review; two 45-degree turns usually beat one tight 90. Walk the drawing before installation and strike out fittings that exist only because nobody challenged them.
Low Point Management with Condensate Traps
Vapor cools as it travels and condenses at the low points a sloped line inevitably creates. Plan for them: place condensate traps at the low points the drawing shows, keep them accessible for draining, and never bury a trap where the drain cannot be reached. A trap that cannot be drained becomes a liquid plug that throttles the whole line.
Isolation Valves for Service Access
Isolation valves at the unit boundary let maintenance happen without opening the whole station vapor system. Locate them where a technician can reach them standing, with gauge ports nearby so the line condition can be read without disassembly. Service-friendly isolation turns a half-day outage into an hour of work.
| Layout choice | Long-term effect |
|---|---|
| Short direct route | Lower resistance, less condensate |
| Gentle bends, fewer fittings | Reduced pump workload per cycle |
| Traps at designed low points | No hidden liquid plugs |
| Isolation at unit boundary | Fast service, short outages |
Common Questions
How much slope does vapor piping need?
Enough to move condensate to the designed trap under gravity without creating a sag between supports. The site drawings set the value; the installer’s job is holding it continuously.
Can traps be shared between branches?
A trap serves the low point it sits under. Merging branches above a shared trap works only when both slopes genuinely reach it; otherwise one branch hides its own low point.
Does VOHON advise on piping layout for its Stage III equipment?
Yes. VOHON supports Stage III vapor recovery projects with layout guidance covering header sizing, trap placement and isolation practice, reachable at lixiang@vohon.cn.