Flow Measurement

Metal Tube Variable Area Flow Meter


MT28 metal tube variable area flow meter


MT28 Metal Tube Variable Area flow meters are suitable for the flow metering and flow consumption of liquids, gases and vapour, and operate on the float principle. The MT28 measuring section features a tapered metal tube in which a suitably shaped float is allowed to move freely up and down. Depending on the flow rate, the float will assume a certain vertical position in the measuring section. The float position is transmitted by magnetic coupling to the scale on the indicator. The flowmeters are particularly suitable for difficult application, operating and environmental conditions.

mt28 metal tube variable area flow meter process connections

  • Various wetted materials are available (Stainless steel, PTFE and Hastelloy C) for process mediums.
  • Die-cast aluminum housing with epoxy paint for indicator housing (IP65), also optionally available in stainless steel.
  • Vertical, horizontal & side mounted version for special installation positions.
  • Modular rack housing accommodate all electrical functions and scale plate, modules of electrical options can be replaced or retrofitted without interrupting the process.
Special Options: 
Limit Switches, L• 2 limit switches
• Adjustable on the scale (Can be retrofitted)
Electrical Current Output, CUR• Non-interacting and hysteresis-free conversion of the flow value into a scaled current output, 4-20 mA with HART
Flow Totalizer, FT• Used in conjunction with CUR
High Temperature, HT• Meter with built-in electrical components is mounted on extended spacers if process temperature should exceed the max. allowable level
Inlet Needle Valve, TE• Connected at the inlet of flow meter
• Used for on-off, throttling and regulating purpose
Outlet Needle Valve, TA• Connected at the outlet of flow meter
• Same purpose as TE
Inlet Differential Pressure, IR• Help to maintain a constant flow rate at variable inlet pressure
Outlet Differential Pressure, OR• Help to maintain a constant flow rate at variable outlet pressure
  • For liquid (both conductive and non-conductive) and gas measurement
  • MT28 is particularly suitable for difficult applications and tough environmental conditions.
For example:
High temperature, high pressure as well as corrosive environment. Can be used in all industrial sectors, such as:
  • Chemical
  • Waster / Wastewater
  • Marine / Offshore
  • Pulp and Paper
  • Pharmaceutical
  • Food and Beverage
  • Oil and Gas

Flow Meter

Measuring Range (100% Value)Water (20°C): 25 to 100 000 l/h
Air (1.03 bar abs. 20°C): 0.7 to 600 m3/h
Turndown Ratio10:01
Accuracy Class1.6 (VDI/VDE Code 3513, Part 2)
Flow ScaleFlow units
Ambient Temperature Ta-40°C to +120°C
Max. Process TemperatureMT28/SS, MT28/HC: -80 °C to +300°C
Tp Without built-in electrical optionMT28/PT : -80°C to +70°C
Max. Process Temperature Tp With Built-in Electrical OptionRefer to Sales
Test Pressure PT (Pressure Tested)The test pressure is calculated in accordance with pressure equipment directive (97/23/EC) and/or AD 2000-HP30, in compliance with the maximum allowable operating pressure and the maximum operating temperature
Meter SizeDN15 to DN100 and ½” to 4”


FlangeDIN2501 DN15 – 100, PN16 – 250
ANSI B 16.5 ½” – 4”, 150 – 2500 lbs
JIS B 2238 15 – 100, 10 – 20K
ThreadISO 228 G½” – G1”
ANSI B1.20.1 ½” – 1” NPT >50 bar
SanitaryTri-Clamp ISO 2852 Size 25 -139, 10 – 16 bar
SMS 1146 1” – 4″, 6 bar
DIN 11851 DN15 – 100, 25 – 40 bar


FlangesSS316L (1.4404) (Standard)
Hastelloy C
Wetted PartsSS316L (1.4404) (Standard)
Wetted Parts SS304 (1.4301) with PTFE liner
Hastelloy C
HousingDie cast aluminum with epoxy paint
Optional: Stainless steel housing
Measuring TubeMetal tube with tapered measuring section

Overall Height

Standard for Flange & Sanitary Connection250 mm
Standard for Thread300 mm
Protection CategoryIP65, NEMA 12 & 13

 Note: Specifications are subject to change without notice

  • Higher pressure rating and other types of connection available on request
  • Non-standard lengths can be customized to suit existing piping dimensions