How do I use the mass flow controller?

When using a mass flow controller, follow these steps

  1. Make piping connections.
  2. Perform leak checks.
  3. Make necessary electrical connections (power supply, set voltage, etc.).
  4. Turn on the power supply and check for any deviation from the zero point.
  5. Apply pressure to the primary side to generate differential pressure to the mass flow controller.
  6. Input the flow rate you wish to set to the mass flow controller.

1.Piping connection

Pipe diameter

The general piping diameter used in mass flow controllers is often 1/4inch (approx. 6.35mm). Depending on the fluid and flow rate, pipes with diameters of 1/16inch, 1/8inch, 3/8inch, 1/2inch, etc. are used. Therefore, mass flow fittings must also be selected to match these diameters.


Mass flow controller fittings are mainly VCR type and Swagelok tube fittings.。

VCR Type

VCR type fittings are male and female, with the mass flow side generally being male. Sandwich the metal gasket between the male and female joints, hand-tighten the nut on the female side, and then tighten it 1/8 turn with a wrench. (This will vary depending on the material of the gasket.)

Swagelok Tube Fittings

Tube fittings, also known as Swagelok fittings, have a fitting, nut, and ferrule on the mass flow controller side. The pipe is connected to the fitting by inserting the nut and ferrule through the pipe and tightening the nut.

What is the key to using mass flow controllers with high accuracy?

  1. After turning on the power, allow the unit to warm up for approximately 30 minutes. Turning on the power heats the thermal sensor, but warming up improves stability.
  2. Press Zero Point Reset when gas is completely off. For more information, click here.
  3. Keep signal cables as short as possible. Setting and output signals are 0-5V voltage signals. If the cable is long, the signal may drop due to voltage drop.
  4. Do not connect the power supply, setting voltage, and output voltage commmons on the device side to each other.
  5. Stabilize the supply pressure to prevent sudden pressure fluctuations. This will minimize the influence of flow control.
  6. When liquefied gas is used, heat the piping so that cold spots (cooling points) do not occur in the piping. If re-liquefaction occurs, rapid pressure fluctuations may result, causing flow instability.

These are the key points for using mass flow controllers with higher accuracy. By paying attention to these precautions, accurate flow control can be achieved.