Tokyo Ryuki Kogyo RM 245 Mass Flow Meter


The basic configuration of the mass flow meter consists of a thermal mass flow sensor, a bypass laminar flow element, and a bridge circuit. An electric current is passed through the resistor wound around the sensor to generate heat. When a part of the gas that enters from the inlet flows into the sensor, the temperature distribution of the sensor changes, which is captured by the bridge circuit and taken out as a flow rate output signal.

  • Can be used with a single power supply mass flow meter DC24V instrument power supply.
  • Measure mass flow rate with little pressure effect.
  • Compact size allows flow rate measurement up to the 60SLM class area.
  • A dedicated power supply is available.

General Specifications

Model RM245 type power supply
Power supply used AC100V ± 15%, 50 / 60Hz 10VA
Flow output signal 1 0-5V DC output impedance 47Ω
(receiver input impedance 100kΩ)
Flow output signal 2 4 to 20mA DC load resistance 1kΩ
Flow indicator connection terminal With connector terminal (4p)
weight About 350g
External dimensions 102 x 125 x 30 (mm)


Ryuki Kogyo

Tokyo Ryuki Kogyo

Tokyo Ryuki Co., Ltd., a manufacturer of industrial flow meters and fluid-related equipment. For many years, we manufacture and sell products such as differential pressure type flow meter, area type flow meter, flow switch, metal tube type flow meter, galvanometer, level meter, and measuring pot.


  • RM-245 type dedicated power supply Built-in dedicated power supply for flow indicator.
  • The flow rate output signal can be taken out from both 0 to 5V DC and 4 to 20mA DC.


  • Air
  • Nitrogen
  • Oxygen


Measurement flow range
(full scale display)
1SLM, 2SLM, 5SLM, 10SLM 20SLM (50SLM)
Flow unit SLM (0 ℃, 1atm)
Gas to be measured Air, N2, O2
Flow accuracy FS ± 1% FS ± 2%
Reproducibility Within ± 0.5% FS
Minimum operating differential pressure 65Pa-2kPa or more 3kPa-9.8kPa or more
Unusable pressure 980kPa (10kgf / cm2G)
Withstand voltage 980kPa (10kgf / cm2G)
External leak standard 1 × 10-7 Pa ・ m3 / sec or less
Usable temperature 5-60 ° C (Accuracy guaranteed: 15 ° C-35 ° C)
Flow output signal 0-5VDC (output impedance 45Ω)
Power supply used + 24V ± 0.5V DC 50mA
Main unit connection port Rc1 / 4
Gas connection member quality SUS303, Byton
External dimensions 59 x 26.6 x 65 (mm)
weight 400g

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