Welcome to the official website of Foshan Zhicheng Gas Co., Ltd!

  • EN
  • CH
  • Email:ZC_GAS@163.COM   Phone:+86-757-81033032


    Standard gas distribution method

    2021-08-30 03:51:19

    There are three methods for standard gas distribution:

    1. Syringe gas distribution method

    When only a small amount of standard gas is needed, a 100ML syringe can be used to prepare the standard gas; after multiple dilutions, the required low-concentration standard gas can be obtained. The concentration of the standard gas can be calculated according to the concentration of the raw material gas and the dilution factor. The syringe used for gas distribution must have good air tightness, small size and accurate system. Put a small piece of polytetrafluoroethylene flake before the gas is prepared for stirring.

    Although the syringe gas distribution method is simple and easy to implement, the concentration of certain standard gases is also very accurate. However, due to the adsorption of the inner wall of the syringe, large dead volume and incomplete liquid volatilization, the concentration of the prepared gas has a large error. The standard gas of the compound is not suitable to be prepared by this method. When using volatile liquids to dispense gas, it is especially necessary to pass the verification before using a syringe to dispense gas.

    2. Plastic bag gas distribution method

    In this method, a plastic bag is used as a container, a certain amount of raw material gas is accurately measured with a gas quantitative tube according to the figure, an appropriate amount of diluent gas is sucked into the plastic bag through a three-way piston with a syringe, and the plastic bag is repeatedly squeezed to mix the gas. Calculate the concentration of standard gas in the bag according to the amount of feed gas and diluent gas.

    When using plastic bags for gas distribution, special attention should be paid to preventing the adsorption of gas on the bag wall, reaction and leakage of the bag wall with the gas, etc. General plastic bags have obvious adsorption effect on most gases and cannot be used for gas distribution. Teflon bags, polyester resin plastic bags and polyethylene film aluminum foil sandwich bags are usually used for air distribution.

    3. Gas distribution method for high-pressure steel cylinders

    This gas distribution method is a method that uses high-pressure steel cylinders as containers to prepare a mixture with a higher pressure, also known as the high-pressure gas distribution method. According to the gas distribution measurement method, the high-pressure steel cylinder gas distribution method is divided into pressure method, flow method, volume method and mass method. Among them, the concentration of standard gas prepared by mass method is the most accurate. It is used as the reference method for preparing standard gas. It is widely used to prepare standard gases such as COCH4 and NO.


    About us
    Honor Certificate
    Product Center
    Rare Gases
    High Purity Gases
    Hydrocarbon Gases
    Gas Mixtures & Calibration Gases
    Stable Isotopes
    Deuterated Compounds
    Contact us




    Address: Room 4805-4806, Building A4, Guangfozhicheng, Dali town, Nanhai District, Foshan, China