Symbol
What it does
The slow way: air squeezes through the restrictor.
The other way: air lifts the ball. It takes the by-pass at full speed.
Kit name: flow control valve.
Key words
- Restrictor
- Narrows the pipe to slow the air.
- Uni-directional
- Slows the air one way only.
- Bi-directional
- Slows the air both ways.
- By-pass
- The other path, where air flows freely.
Sources & credits: Symbols drawn to ISO 1219, as used in N5 Engineering Science. Kit drawings by R Stewart, from the Matrix CP2080 kit. Full site credits are on the credits page. R Stewart - October 2026