Venturi flow element.
A pipe section with a tapered constriction in the middle. Venturi tubes recover pressure better than orifice plates, which matters on services where the permanent pressure loss is expensive.
How it's drawn.
A pipe section that tapers down to a throat and opens back out. The smooth constriction recovers more pressure than a plate, which is why it appears where the permanent pressure loss would be costly. Like the orifice, it pairs with a differential-pressure transmitter to produce a flow reading.
Typical usage.
Large-diameter water service, natural gas pipelines, anywhere the plate-induced loss across an orifice would represent meaningful operating cost. Sized per ASME PTC 19.5.
Telling it apart.
- A venturi is drawn as a tapered section. An orifice plate is a single line across the pipe.
- Both create the pressure drop a transmitter reads. The venturi gives back more of that pressure downstream.
- The element measures nothing on its own. The differential-pressure transmitter carries the flow tag.
Related.
Read every symbol on the sheet.
A pipe section with a tapered constriction in the middle. Venturi tubes recover pressure better than orifice plates, which matters on services where the permanent pressure loss is expensive.