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Coriolis Flow Meter P&ID Symbol and Process Instrumentation Legend Drawing Keys
Quick Answer: A Coriolis flow meter on a P&ID normally appears as a circle with the letters FT or FIT inside. The circle sits on the process line. The process instrumentation legend drawing keys define the exact tag number, line type, and function code. Use the legend keys before you issue any loop drawing or wiring schedule.
Engineers and procurement teams often miss the P&ID symbol for a Coriolis meter. They rely on old magnetic flow meter symbols or generic flow element blocks. In practice, a clean P&ID saves time during FAT, SAT, and commissioning. Because a wrong symbol can cause a vendor to quote the wrong device.
We have seen this on customer sites in Vietnam, Thailand, and Nigeria. A project drawing showed a generic flow transmitter. The vendor quoted an electromagnetic flowmeter. The process was a high viscosity palm oil line. The meter failed within weeks. A Coriolis meter with the correct P&ID symbol and legend note would have avoided that.
Typical Coriolis Flow Meter P&ID Symbol
Most projects follow ISA 5.1 or a national derivative. The Coriolis flow meter is drawn as a single instrument bubble on the process pipe. The bubble contains FT if the meter transmits flow only. FIT is common when the transmitter also has a local display. FIQ is used if a totalizer function is integrated.
A magnetic flowmeter symbol also uses FT. So how do you know it is a Coriolis meter. The legend note must say Coriolis mass flowmeter. Some drawings add the letter M inside the bubble or next to it. Others use a small note. Do not rely on the symbol alone.
A separate FE bubble is not required for most Coriolis meters. The sensor and transmitter are one package. Some project legends still split FE and FT. This is acceptable if the legend drawing keys state that the FE represents the Coriolis sensor tube and the FT represents the transmitter electronics.
The pipe line passes through the bubble or the bubble touches the line with a solid leader line. The leader line type matters. Solid lines mean field mounted. Dashed lines mean panel or DCS mounted. A Coriolis meter transmitter is usually field mounted. So the bubble should sit close to the process pipe with a solid leader line.
Instrument Legend Drawing Keys for Coriolis Meters
Legend drawing keys are not decorative. They define the symbol set for the whole project. A typical legend sheet lists four things for a Coriolis flow meter. The bubble style. The tag letters. The line type. The signal type.
For example, a project in Malaysia used the following legend. Field mounted flow indicating transmitter, circle 12 mm diameter, letters FIT, solid leader line, 4-20 mA HART signal to PLC. That single row in the legend avoided two rounds of drawing comments.
Most engineers skip this part. They copy symbols from a previous project. But a legend from a water treatment plant may use different letters than an oil and gas platform. Check the legend first. It takes ten minutes. It saves a week of drawing revisions.
Tag Numbers and Loop Identification
Tag numbers sit inside the bubble. A common format is 12-FIT-101. The first number is the unit or area. FIT is the function. The last number is the loop serial. A Coriolis meter on a fuel oil line may be tagged 23-FIT-204. The loop drawing then refers to the same tag number.
Use the same tag number on the P&ID, loop drawing, I/O list, and nameplate. Mismatched tag numbers are a common cause of punch list items. A customer in Indonesia lost three days during commissioning because the loop drawing said 15-FT-330 and the P&ID said 15-FIT-330. The
Specify the process variable on the legend if the Coriolis meter measures mass flow. Add a note like mass flow kg/h, density kg/m3, temperature °C. This helps the electrical engineer understand the transmitter outputs. It also helps the process engineer set alarms.
Common Mistakes on P&ID for Coriolis Meters
One common mistake is using the orifice plate symbol for a Coriolis meter. The orifice symbol is a circle with a diagonal line or a restriction on the pipe. A Coriolis meter does not create a differential pressure. Do not use the orifice plate symbol.
Another mistake is omitting the local display note. Many Coriolis transmitters have a local LCD. If the P&ID does not show this, the operator may expect a separate indicator. Add a note under the bubble. Local display included. This small line reduces field questions.
Pressure and temperature compensation are part of the Coriolis meter internal calculation. You do not need external PT100 compensation on the P&ID for most models. But some project specs still ask for PT100 in the line. Confirm the vendor model supports direct density and temperature output. Silver Instruments supplies Coriolis meters with built-in PT100 for mass flow and density correction. The loop drawing can show a single 4-20 mA HART output for mass flow and a digital signal for density.
Silver Instruments Coriolis Flow Meter Models and P&ID Support
Silver Instruments is a Coriolis flow meter manufacturer and supplier. We offer direct mass flow measurement for DN15 to DN200 lines. Our Coriolis meters handle liquids from 0.1 cP to 50,000 cP. They suit chemical dosing, palm oil, molasses, bitumen, and food and beverage lines. Ex approvals include ATEX Zone 1 and IECEx. Typical outputs are 4-20 mA HART, pulse, RS485 Modbus.
If you need a P&ID symbol package, we provide 2D CAD blocks and ISA 5.1 based legend rows for our Coriolis flow meters. This saves your piping team from redrawing symbols. Send us your pressure (bar), temperature (°C), pipe size (DN), and flow range for a quote. Email or call Silver Instruments. Tel: +86-25-68650347. WhatsApp: +86-25-52155837. WeChat: +86 15365082610. Visit flow-meter.com.au for data sheets.
FAQ: Five Common Questions From Engineers
What is the P&ID symbol for a Coriolis mass flow meter?
The symbol is usually a single circle with FT or FIT inside. The circle sits on or near the process line. Some legends use FIQ for indication and totalizing. Always check the project legend drawing keys.
Does a Coriolis meter need separate FE and FT symbols on a P&ID?
Not usually. Most Coriolis meters combine the sensor and transmitter in one package. A single FIT bubble is cleaner. Some projects still use separate FE and FT bubbles. Follow the project legend.
What tag letters should a Coriolis flow meter use?
Use FT for flow transmitter. Use FIT for flow indicating transmitter. Use FIQ if the device provides pulsed totalizer output. The first letter F means flow. The second and third letters define function.
What line type should connect the Coriolis meter bubble to the pipe?
Use a solid leader line for a field mounted transmitter. Use a dashed line if the transmitter electronics sit in a control panel or DCS cabinet. Most Coriolis meter transmitters are field mounted. So solid leader line is standard.
How do we get P&ID CAD blocks for Silver Instruments Coriolis meters?
Contact Silver Instruments with your pipe size and project drawing standard. We can supply 2D CAD blocks and legend row text for ISA 5.1 based drawings. Tel: +86-25-68650347. WhatsApp: +86-25-52155837.