Symbol 1701 from ISO 7000 - Title/Meaning: Pressure Function/description: To indicate pressure.
Additional information: 
Use primarily as a symbol element in combination with other symbols to indicate the type of medium that is under pressure. The filled circle may be deleted and an appropriate symbol inserted between the arrows.
Own work using: iso.org/obp/graphics/grs/8be0aa78-8b95-4471-a949-ba84f2eb2fb6 200.png
Vectorization:  Mrmw