Orifice plate, flow element.
A vertical line bisecting the pipe represents an orifice plate flow element. Pair it with a differential pressure transmitter, PDT or FT and you have one of the most common flow measurements in process plants.
How it's drawn.
A line across the pipe marking the plate, paired with a differential-pressure transmitter that reads the drop across it. The plate creates the measurable pressure difference. The upstream and downstream taps feed the transmitter. The transmitter reports flow. It is one of the most common flow elements on a process drawing.
Typical usage.
Sized per ISO 5167 or AGA 3 depending on service. The plate creates a measurable pressure drop. The upstream, downstream taps feed the DP transmitter. The transmitter outputs scaled flow to the BPCS.
Telling it apart.
- The plate is the element, not the measurement. It needs a differential-pressure transmitter to produce a flow reading.
- An orifice plate and a venturi both create a pressure drop. The venturi recovers more of the pressure and is drawn as a tapered section, not a single line.
- The flow tag belongs to the transmitter and loop. The plate itself is the primary element feeding it.
Related.
Get the P&ID symbol cheat sheet.
One page of primary-element geometry, including the orifice plate and the flow elements drawn beside it.