What is flow rate?

There are two types of flow rate: instantaneous flow rate and integrated flow rate.

”Instantaneous flow rate"

"Instantaneous flow rate" specifies the volume or mass of flow per fixed amount of time. When considering volume as the amount of fluid, it is called volumetric flow rate. Generally speaking, the flow rate often refers to the volumetric flow rate, and in the Japanese Measurement Law, the volumetric flow rate is simply expressed as the flow rate. As for considering mass, it is called mass flow rate.

"Integrated flow rate"

"Integrated flow rate" specifies the cumulative value of flow used from the start to finish of measurement.


Units of Instantaneous flow rate

  International System
of Units (SI)
Measurement Law
Instantaneous volumetric
flow rate
[m3/s] [L/h], [L/min] can be used.
Instantaneous mass
flow rate
[kg/s] [kg/h], [g/min], [g/s] can be used.

Units of Integrated flow rate

  International System
of Units (SI)
Measurement Law
Integrated volumetric
flow rate
[m3] [L], [mm3] can be used.
Integrated mass
flow rate
[kg] [g] can be used.

* Since the volume changes depending on the pressure and temperature, the measurement conditions such as temperature and pressure are specified. When indicating "standard state" in the measurement conditions, it is necessary to specify in which standard the standard state is as the standard pressure and standard temperature differ depending on the standard.


Flow rate measurement

We provide various detectors to measure the fuel consumption of internal combustion engines with high accuracy. You can choose the detector according to your application.


How to select detectors

  1. Check the state and properties of the fluid to be measured.
  2. Check the state of the fluid you want to measure and its basic properties: flow rate range, fluid temperature, pressure, density, viscosity, vapor pressure, corrosiveness, etc.

  3. Clarify the measurement purpose and decide the detection method.
  4. Determine the detection method in consideration of the measurement purpose and the entire measurement system: required flow rate accuracy and resolution, integrated value of a constant flow rate, transient fluctuation of flow rate with high accuracy, flow rate in a dangerous area,

  5. Confirm the product specifications and decide the product.
  6. Narrow down the products that meet the requirements of 1. and the detection method of 2. Please contact to our sales office nearby for detailed specifications.

Guideline for considering the flow rate measurement system

Item Contents Detection system
Fuel type Gasoline, light oil, kerosene, alcohol mixed fuel, LPG (liquid), gas Gas flow rate can be measured with the FZ series depending on the conditions. Other than that, FP series, FZ series and FX series can all be measured.
*Please note that the test report will not be for gas calibration but for liquid calibration.
Required units Volumetric flow rate (L/h) The FP series enables to measure directly the volumetric flow rate. The FZ series converts the measured density data to the volumetric flow rate.
Mass flow rate (kg/h) By combining the density meter FD-5110 and the FZ series, the FP series can calculate the mass flow rate in real time. The FZ series and the FX series are capable of making direct flow rate measurement by mass.
Flow rate range Measure 1.0 to 80 L/h Select a detector according to the measurement range of each product.
Transient measurement Graph the instantaneous flow rate with sampling of 10 ms The FM-3100 captures transient flow rate changes and provides signal output either analog or CAN at 1 ms cycle. It supports various detectors such as FP series, FZ series and FX series. For FZ, FX series, output cycle is 100 ms.
Primary fuel supply pressure 300 kPa If the primary fuel supply pressure is 100 kPa or more, the FP series can be installed and the flow rate can be measured normally. As the pressure loss of FZ series is 0.1 MPa at 1090 kg/h, need to consider the relationship with the secondary supply pressure.
*For engine benches, the primary fuel supply pressure refers to the pressure at the fuel supply port in the building.
Secondary fuel supply pressure 350 kPa In the case, the secondary supply pressure is higher than the primary supply pressure, so it is necessary to boost the pressure with a pump. Assembly is required including the detectors. Please contact to our sales office nearby.
*For engine benches, the secondary fuel supply pressure refers to the supply pressure to the engine.
Temperature control Need/ No need If the temperature control is required, such as keeping the fuel supply temperature constant, assembly is required. Please contact to our sales office nearby.


Example of system configuration



Volumetric flow detectors      
  Standard type Low pressure loss type Environment resistant type
Small flow rate type FP-5130 series FP-213S FP-4135
Medium flow rate type FP-5140 series FP-2140S
Large flow rate type FP-5150 series -
Fuel Density Meter
Standard type FD-5110
Massflow Meter
Small flow rate type made to order
Medium flow rate type FZ-2200A
Mass-Burette Flow Detector
Small flow rate type FX-1110
Medium flow rate type FX-1120
Large flow rate type FX-1130