Understanding Flow Measurement
What is flow rate?
Flow rate can be categorized into instantaneous flow rate and cumulative flow rate.
"Instantaneous flow rate"
This refers to the volume or mass of fluid flowing per unit time.
When considering the volume of a fluid, it is called volumetric flow rate. Generally, when people refer to flow rate, they are often referring to volumetric flow rate, and even in Japan's Measurement Law, volumetric flow rate is simply referred to as flow rate. When considering mass, it is called mass flow rate.
"Cumulative flow rate"
This refers to the cumulative value of the amount that flowed from the start to the end of the measurement.
The term "flow rate" can refer to various things, and if you don't clarify which flow rate is being discussed based on the surrounding context and units, the conversation may not make sense.
Units of instantaneous flow rate
| International System of Units (SI) | metrology law | |
| Instantaneous volumetric flow rate | [m3/s] | [L/h] and [L/min] are also accepted. |
| instantaneous mass flow rate | [kg/s] | [kg/h], [g/min], and [g/s] are also accepted. |
Unit of cumulative flow
| International System of Units (SI) | metrology law | |
| Cumulative volumetric flow rate | [m3] | [L] and [mm3] are also recognized. |
| Integrated mass flow rate | [kg] | [g] also acknowledges this. |
* Since volume changes with pressure and temperature, measurement conditions such as temperature and pressure must be clearly stated. If "standard conditions" is used in the measurement conditions, it is necessary to specify which standard conditions are being referred to. (Standard pressure and temperature vary depending on the standard.)
Flow rate measurement
We offer a variety of detectors for accurately measuring the fuel consumption of internal combustion engines. You can choose the detector that best suits your measurement needs.
How to select a pixel
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Confirm the state and properties of the fluid to be measured.
We will confirm the conditions to be measured and the basic properties of the fluid at that time, such as the flow rate range, fluid temperature, pressure, density, viscosity, saturated vapor pressure, and corrosiveness. -
Clearly define the objective and determine the detection method.
We determine the detection method by considering your desired measurement objectives and the overall system, such as the required flow rate accuracy and resolution, whether you want to measure the cumulative value of a constant flow rate, whether you want to capture the change in transient flow rates with high precision, whether you want to measure flow rates in hazardous areas, or whether you want to control the fluid temperature and pressure in addition to flow rate measurement. -
Review the product specifications and narrow down the products to be adopted.
From the products that match the detection method in 2., we will narrow down the selection to products that meet the requirements in 1. For detailed specifications, please contact our sales department.
Examples of Flow Measurement Systems
| Items to consider | example | Content |
| Fuel type | Gasoline, diesel fuel, alcohol-blended fuel, LPG (liquid), gas | The FP, FZ, and FX series are designed for liquid measurement. For substances like LPG, which are gases at room temperature and pressure but become liquids when pressurized and cooled, the system is designed to maintain the liquid state. Gas flow rate measurement is possible with the FZ series depending on the conditions. *Calibration using gases is not possible. The report will be based on the results of tests using liquids. Please note this. |
| Required flow rate (unit) | Volumetric flow rate (L/h) | The FP series allows for direct measurement of volumetric flow rate. The FZ series allows for the conversion of simultaneously measured density data into volumetric flow rate. |
| Mass flow rate (kg/h) | The FP series, when combined with the compact Fuel Density Meter FD-5110 or the FZ series, allows for real-time conversion to mass flow rate. The FZ series allows for direct mass flow measurement. The FX series allows for direct mass (weight) flow rate measurement. |
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| Flow rate range | I want to measure within the range of 1.0 to 80 L/h. | Select a detector in accordance with the measurement range of each product. |
| Transient measurement | I want to graph the instantaneous flow rate using 10 ms sampling. | The FP series calculates the flow rate by converting the flow rate into a pulse signal and counting it with the FM-3100. The FM-3100 is capable of outputting in 1 ms (analog/CAN). The FZ series outputs mass flow rate values from the FM-3100 every 100 ms. The FX series outputs weight flow rate values from the FM-3100 every 100 ms. |
| Primary fuel supply pressure | 300 kPa | The FP series can accurately measure flow rates by installing a detector, provided the primary fuel supply pressure is 100 kPa or higher. The FZ series detector has pressure loss of approximately 100 kPa at 1090 kg/h. The relationship with the secondary fuel supply pressure must be considered. *The primary fuel supply pressure refers to the pressure at the building's fuel supply port in the case of an engine bench. |
| Fuel secondary supply pressure | 350 kPa | In this example, the secondary supply pressure is higher than the primary supply pressure, so it is necessary to boost the pressure using a pump or similar device. An assembly including a fuel flow sensor is required. Please contact us for details. *In the case of an engine bench test, secondary fuel supply pressure refers to the pressure supplied to the engine. |
| Temperature control | Not required/necessary | If temperature control is required, such as maintaining a constant fuel supply temperature, an assembly is necessary. Please contact us for details. |
Connection Diagram
Lineup
| Positive flow detector | |||||
| Standard type | Low pressure loss type | Explosion-proof type | Compact and environmentally resistant Improvement type |
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| Pressure-resistant explosion-proof | Internal pressure explosion protection | ||||
| Low flow rate type | FP-5130 series | FP-213S | FP-3130 series | FP-3130S series | FP-4135 |
| Medium flow rate type | FP-5140 series | FP-2140S | FP-3140 series | - | |
| High flow rate type | FP-5150 series | - | FP-3150 series | - | |
| small Fuel Density Meter | |
| Standard type | FD-5110 |
| Coriolis continuous mass flowmeter | |
| Low flow rate type | Made to order |
| Medium flow rate type | FZ-2200A |
| Mass burette type flow meter | |
| Low flow rate type | FX-1110 |
| Medium flow rate type | FX-1120 |
| High flow rate type | FX-1130 |
Measurement principle
Measurement principle of flow detectors
Measurement principle of the FP series positive displacement flow detector
Four pistons arranged radially in the flow detection unit reciprocate as the liquid flows from the inlet to the outlet. This piston movement is converted into rotational motion by the crankshaft and transmitted to the rotation detection unit, which is magnetically coupled.
The rotary encoder in the rotation detection unit generates a pulse signal corresponding to the piston's movement capacity, and the flow meter calculation and display unit calculates and displays the instantaneous flow rate and integrated flow rate. The pulse signal is generated by two sets of light-emitting and light-receiving elements with a 90-degree phase difference, and by determining the direction of rotation, accurate flow rate measurement can be performed without being affected by backflow or pulsating flow.
Measurement principle of the FZ series Coriolis continuous mass flow detector
The measurement principle is based on the Coriolis force, which is generated when mass transfer and rotational motion occur simultaneously.
Liquid entering through the inlet passes through the tube and exits through the outlet. This flow meter generates a Coriolis force by applying a specific vibration to the tube, causing it to move in a manner equivalent to angular velocity. As shown in the diagram, the tube experiencing the Coriolis force undergoes a twist proportional to the mass flow rate, and the mass flow rate is calculated from this amount of twist.
Measurement principle of the FX series mass burette type flow detector
When the liquid level drops below L3, the solenoid valve V1 opens and the liquid is filled. When the liquid level reaches L2, V1 closes, and after the set liquid level stabilization time has elapsed, instantaneous flow rate measurement begins. As the liquid level drops from L2 due to consumption, the output of the differential pressure transducer also changes according to the weight of the consumed liquid. The weight flow rate is determined from this change and displayed digitally on the FM series flow meter.
The measurement of cumulative flow rate is,
- Between manual start and stop
- From the start to the set cumulative flow rate
- From the start until the set time
L1 is the overflow detection level, and L4 is the fluid depletion detection level, both of which trigger alarms from the display (each liquid level from L1 to L4 is determined from the output level of the differential pressure converter).