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  1. #1
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    Gas flow meter + Gas pressure meter + Vacuum meter?

    I have an 8mm hose that flows the gas. Gas is Air or CO2 or Agron. Gas pressure is 0-10bar.

    1.Pressure
    Can you recommend a pressure sensor? 0-10bar, Voltage or digital output, resolution min 12bit, to PCB with 4/6mm hose or direct to 1/8" or 1/4" fitting, low price , I do not resist the Chinese product.

    2. Flow
    I also need to measure the amount of gas flowing through it. Now we use flow meters with a ball any as this

    Is there any cheap method / sensor that can convert flow to voltage for MCU processing?

    3. Vacuum measurement?
    You can recommend a sensor that could be used to measure vacuum
    about differential input, one to atmosferic pressure, second under vacuum , and min 12 bit resolution, voltage or digital output. low price

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  2. #2
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    Re: Gas flow meter + Gas pressure meter + Vacuum meter?

    2. There's no simple method to add a readout to float-type flowmeter (rotameter). Most economic flow meters (I doubt you find cheap sensors with suitable precision) have thermal or pressure drop operation principle, also some simple turbine flow meters are on the market. Depends much on the intended flow range, precision, gas type.

    For some applications, a rotameter with light barriers can be used as limit switch, e.g. for min/max flow.

    3. Consider if you want to measure pressure below actual atmospheric pressure (differential measurement) or absolute pressure (uses vacuum reference). Depends on your application, both sensor types are available.



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  3. #3
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    Re: Gas flow meter + Gas pressure meter + Vacuum meter?

    2. I was looking for a small turbine for gases, but I found them only for liquids
    I need to measure the argon flow 0-10l / min and air flow 0-100l/min
    accuracy is not critical


    3.
    The price is decisive.
    Technically, I need to measure against a reference vacuum.
    Practically I am interested in pressure between 100Pa - 20kPa
    Now I have a large mechanical vacuum gauge, we estimate pressures below 1kPa based on the sound of the pump



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  4. #4
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    Re: Gas flow meter + Gas pressure meter + Vacuum meter?

    Quote Originally Posted by berger.h View Post
    The price is decisive.
    Pressure of 1 kPa barely moves the needle on an everyday automotive vacuum gauge. This low pressure might be detected by the depth of liquid a hose is immersed and still allow gas to flow. The liquid should be chosen so no harm is done if it contaminates the gas.

    Flow rate is indicated by the bubbling of gas in the liquid, either bubble size, or frequency, or loudness, etc. Frequency per minute seems easy to count with a low-cost electronic circuit.



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