Miniature Metal Tube Variable Area Flowmeter – MMT18 / MMT19


isolviSOLV MMT18 VA flowmeter measures volumetric flow rate of liquid and gases that operates on the float principle. It features a metal tube, in which a float is allowed to move freely up and down. The float reaches a stable position when the upward force exerting by the flowing liquid equals the weight of the float. The float position is transmitted by a magnetic coupling system to the scale. The rotational movement of the follower magnet system transmitted to the indicator is linearised and the flow rate is indicated directly on the scale.


General Features

  • Suitable for liquids and gases.
  • Suitable for installation in which flow direction is from bottom to top.
  • Tapered metering section of rugged all-metal construction.

Standard Features - MMT18

  • With horizontal connections.
  • A needle valve at the inlet or bottom front of connection block.

Standard Features - MMT19

  • With vertical connections.
  • Without needle valve.


  • Can be supplied without valve, or with outlet needle valve at the top connection block (OutLet).
  • A maximum of two adjustable limit switches (L1, L2). The set limits are indicated on the scale.
  • Addition of a differential pressure regulator.


  • A maximum of two adjustable limit switches (L1, L2). The set limits are indicated on the scale.
Full-scale range (100% values):
Water at 20°C (68°F): 3 to 100 l/h (0.013 to 0.44 US GPM)
Air at 1.013 bar abs., 20°C (14.7 psia, 68°F): 50 to 3400 l/h (0.031 to 2.11 SCFM)
Turn-down ratio 10:1
Accuracy class (to VDI/VDE Code 3513, Sh. 2): 4
Scale graduation: flow units
Max. allowable operating pressure: Test pressure is 1.3 times the specified operating pressure.
at 20°C (68°F). 130 bar (1885 psig) Information on higher pressure levels supplied on request
Max. process temperature:
Without limit switch option – 80°C to +150°C (–112°F to +302°F)
With limit switch option (Ambient temperature Ta) Ta<40°C (<104°F) | Ta<50°C (<122°F) | Ta<60°C (<140°F)
145°C 293°F | 135°C 275°F | 125°C 257°F
Standard 1 /4” NPT female thread
Adapters Ermeto 6 or 8, Serto 6 or 8, Others upon request
Connection blocks, valve, plug CrNi steel 1.4571 (316Ti)
Housing die-cast zinc
Cone, float CrNi steel 1.4571 (316 Ti)
Gaskets PTFE, other upon request
Limit switch:
Type SJ2-SN
Number, max. 2
Electrical connection Right-angle plug, style to DIN 43650/ISO 4400, with PG 11 cable gland
Max. signal cable length 1.5 m (5 ft) non-detachable
Protection category to EN 60529/IEC 529 An isolation switching amplifier is required to operate the SJ2-SN IP 65, equivalent to NEMA 12 and 13

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