Check valve symbol
Also called Non-return valve, NRV
A check valve lets fluid flow in one direction only and closes automatically if the flow reverses. It protects pumps and compressors from backflow.
What the check valve symbol means
A check valve lets fluid flow in one direction only and closes automatically if the flow reverses. It protects pumps and compressors from backflow.
How it is drawn
The two-triangle valve body with one triangle filled in. Flow goes from the open side towards the filled side; some legends add an arrow.
Variants
- Swing, lift, dual-plate and ball check valves share the symbol, with a note
The check valve symbol in each standard
Drawn as on most US-style legend sheets.
Check valve (general). A plain valve body with a small solid dot on the upper corner of the inlet side. Globe-type and swing check valves have their own numbers (X2113, X8078).
ISO SVG
German (DIN): Rückschlagventil. See DIN P&ID symbols.
Where you see it on a P&ID
On pump and compressor discharges, on lines feeding into a common header, and on utility connections.
Tag codes
The check valve is commonly tagged:
- Usually untagged, or by line number
Tag formats follow the project numbering procedure. For instruments, the letters follow ISA 5.1, explained on the instrument symbols page.
Related symbols
Frequently asked questions
What does the check valve symbol look like on a P&ID?
The two-triangle valve body with one triangle filled in. Flow goes from the open side towards the filled side; some legends add an arrow.
What is a check valve used for?
A check valve lets fluid flow in one direction only and closes automatically if the flow reverses. It protects pumps and compressors from backflow. You will find it on pump and compressor discharges, on lines feeding into a common header, and on utility connections.
What tag does a check valve have?
It is commonly tagged Usually untagged, or by line number. The exact tag format comes from the project numbering procedure and the legend sheets.
Is the check valve symbol the same in ISA and ISO?
No. A plain valve body with a small solid dot on the upper corner of the inlet side. Globe-type and swing check valves have their own numbers (X2113, X8078). The ISO 10628-2 registration number is X8077. Always check the legend sheets at the front of the P&ID set.
What is the check valve called in German?
Rückschlagventil. On a German R&I-Fließschema it is drawn to DIN EN ISO 10628-2.
- In production since 2014
- Thousands of daily users
- On MODEC FPSO projects since 2016