They are mechanical meters that are capable of instantaneous and total (volumetric) flow, which work on differential pressure principle. They are systems that are capable of measuring with plates called orifice that when placed in flow line before and after, create pressure difference.

TECHNICAL SPECIFICATIONS
Connection : DN15…DN300
Measurement Range : 0…700mbar
Display : 4 digit LCD
Precision : % 0,5…1
Supply Voltage : 10…36 V DC
Output : 4…20 mA + HART
Operation Temperature : -40˚ ~125˚C
Protection Class : IP67, NEMA 4 equal
Wet sections : Stainless steel 316
Service : Liquid, Gas, Steam