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    Small Gas Mass Flow Meter, Air/O2/N2, 0-2/5/50L/min
    Picture of Small Gas Mass Flow Meter, Air/O2/N2, 0-2/5/50L/min
    Picture of Small Gas Mass Flow Meter, Air/O2/N2, 0-2/5/50L/min
    Picture of Small Gas Mass Flow Meter, Air/O2/N2, 0-2/5/50L/min
    Picture of Small Gas Mass Flow Meter, Air/O2/N2, 0-2/5/50L/min

    Small Gas Mass Flow Meter, Air/O2/N2, 0-2/5/50L/min

    4.8 out of 5 based on 7 reviews | Write a review
    $445.58
    Small gas mass flow meter is characterized with compact size, high accuracy and good repeatability, designed for low gas flow rate (0-2/ 5/ 50L/min) in the gas lines of 3mm and 8mm in diameter, easy for installation with BST1/4 (R1/4) connection, LED display instantaneous flow rate and flow accumulation, suitable for wide applications involving compressor air, O2, N2, etc.
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    SKU: ATO-FLOW-MF4000
    30-day Returns
    Free Shipping
    Delivery date: 6-12 days

    Compact andlight gas mass flow meters are designed for low gas flow rate measurement in the gas pipelines of 3mm and 8mm in diameter, and have flow rate range of 0~2, 5 L/min and 0~20, 50 L/min available with BST1/4 (R1/4) connection. Featuring high sensitivity and fast response time, the gas flow meters are suitable for process gas control, environmental sampling and many other industrial applications.

    Specification

    Model ATO-MF4003 ATO-MF4008
    Flow Range * 0~2, 5 L/min 0~20, 50 L/min
    DN 3mm 8mm
    Gas * Air, N2O, CO2, O2, N2, Ar.
    For other gases, please contact us.
    Turn-down Ratio 100:1
    Accuracy ±(1.5+0.2)% FS
    Repeatibility 0.25%
    Zero Drift ±30mV
    Output Drift ±0.12%/°C
    Response Time 10ms (default, 20, 50, 100, 200, 500, 1000 settable)
    Power Supply 8-24V DC, 50mA
    Signal Output * Linear: Analog 1-5V DC (Standard); RS232, RS485 (Optional)
    Display 4-digit 7-segment LED, 2 LED indicator
    Display Unit Instantaneous flow rate: SLPM, Flow accumulation: SL
    Display Resolution 0.001, 0.01, 0.1 L/min settable 0.01, 0.1 L/min settable
    Working Pressure ≤0.5MPa
    Pressure Loss ≤100Pa ≤600Pa
    Working Temperature -10°C ~ +55°C
    Storage Temperature -20°C ~ +65°C
    Humidity <95%RH (no icing or condensation)
    Keyboard 3 keys
    Pin Out 5 Pins, NS-TECH CD R-5
    Mechanical Connection BSPT 1/4 (R1/4)
    Calibration Air @20°C, 101.325kPa
    Weight 75g

    Note: For N2O and CO2, ATO-MF4003 is selectable with 2 L/min, without 5 L/min; ATO-MF4008 is selectable with 20 L/min, without 50 L/min.

    Dimension (unit: mm)

    Gas mass flow meter dimension

    Detail

    Gas mass flow meter detail

    Wiring Diagram Instruction

    Gas mass flow meter wiring diagram instructions

    Pinout Thread Color Definition
    1 Blue TX, RS232 digital signal transmission / RS485B
    2 Green Vout, analog voltage output positive
    3 Red VCC, power input positive (8 - 24 Vdc)
    4 Black GND, power/signal ground
    5 Yellow RX, RS232 digital signal receive / RS485A


    Application

    Gas mass flow meter application

    Tips: Working principle of small gas mass flow meter

    A mini gas mass flow meter calculates the mass flow rate of a gas by measuring the change in heat generated by the gas as it flows through the sensor. The sensor usually consists of two temperature probes, one located before the gas flows and the other after. As the gas flows, heat is transferred from the sensor to the gas, resulting in a change in temperature. Based on this change, the flow meter is able to derive the mass flow rate of the gas.

    Small gas mass flow meters are widely used in industrial gas measurement, laboratory testing, medical equipment and environmental monitoring. They are particularly suitable for applications where precise gas quality control is required, such as gas pipeline monitoring, gas consumption monitoring and gas delivery systems.

    Existing reviews of Small Gas Mass Flow Meter, Air/O2/N2, 0-2/5/50L/min
    Operating at atmospheric pressure
    We will be operating at atmospheric pressure. Is this flow meter suitable for our application?
    From: Debbies | Date: 16/03/2026
    Was this review helpful? Yes No (0/0)
    ATO Responded
    Hello, for normal pressure, you can directly purchase this flow meter ATO-FLOW-MF4000.
    Analog Output
    I ordered an ATO-MF4008 flowmeter. The manual states that the maximum analog output is 5V. However, through testing, I can see higher output values. Is the maximum output value corresponding to 50 L/min truly 5V?
    From: Waldson | Date: 07/09/2025
    Was this review helpful? Yes No (0/0)
    ATO Responded
    Yes, under normal circumstances, the maximum output value that corresponds to 50 L/min is really 5V. Could you please tell me what the current voltage is when it exceeds 5V? Is the flowmeter being used beyond its rated capacity?
    Please give me some recommendations
    I want to fill some new double pane insulated window glass units with krypton gas. Thus, I would be using your flow meter to monitor a very slow flow rate (filling through a small 1/32" capillary tube at the bottom of the window unit while the air inside will flow out a capillary tube near the top of the unit.) The windows have a gas volume of 10 liters. I would want a flow rate around 1 liter per minute. Pressures will remain very close to atmospheric pressure. I will also be looking for a regulator to lower the bottle pressure of ~1000psi to 1 psi.
    From: Hollisen | Date: 17/10/2024
    Was this review helpful? Yes No (0/0)
    ATO Responded
    We recommend small gas mass flow meter, SKU: ATO-FLOW-MF4000, 0~2 L/min, please note working pressure≤0.5MPa, see spec on: https://www.ato.com/small-gas-mass-flow-meter
    Can it control the flow to a specified amount with this flowmeter?
    Thank you for this good information.
    Can I control the flow to a specified amount with this flowmeter as well?
    Or is this item just to measure the flow, and I would have to regulate the flow through valving upstream of it?
    From: marge | Date: 19/07/2023
    Was this review helpful? Yes No (0/0)
    ATO Responded
    1. Our flowmeter can only measure.
    2. Yes, you also need valves to control and regulate the flow.
    Can you offer flow meter options for my application?
    I'm actually looking to measure around 0.7 L/min with 1-2% accuracy.  
    Is there any flowmeter option you offer for this application?
    From: fanny | Date: 19/07/2023
    Was this review helpful? Yes No (0/0)
    ATO Responded
    You can choose our ATO-MF4000, the range is 0~2L/min, please refer to the link: https://www.ato.com/small-gas-mass-flow-meter
    But it measures around 0.7 L/min with an accuracy of 2.1%, is it acceptable to you?
    I want to ask some questions about mass flow meters.
    Okay. I was roughly checking the manual, maybe I asked more questions. I want to measure variable flow of gas. Is it possible to sample flows like in each minute and store data? You mentioned about 485 communication, maybe you highlight me on this. Okay, I shall be waiting for you technical details.
    From: Meredith | Date: 13/12/2021
    Was this review helpful? Yes No (0/0)
    ATO Responded
    SKU: ATO-FLOW-MF5700
    See specs, price, and you can order online by credit card at: https://www.ato.com/digital-gas-flow-meter
    For measuring variable flow of gas, it will not affect the reading of the meter as long as it does not exceed its maximum flow range, and you can store data via 485 communication.
    About 485 communication, it also needs your controller or computer to support 485 communication, and you can refer to the communication protocol in the manual.
    Ideal small gas mass flow meter
    This is an ideal small gas mass flow meter for measuring gas flow. I used it to measure the flow rate of a gas pipe with a diameter of 3mm. The measurement result is very accurate and it is a reliable product.
    From: Delco | Date: 08/08/2021
    Was this review helpful? Yes No (0/0)
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