Laboratory gas line check valves (to prevent backflow and cross-contamination) require strict safety considerations during installation, mainly focusing on flow direction, pressure compatibility, and gas type adaptation:

• Flow direction accuracy: Mark the "flow arrow" on the check valve clearly aligned with the gas flow direction. Incorrect installation will cause the valve to fail to open/close normally, leading to pressure buildup or backflow of harmful gases (e.g., backflow of corrosive gas into the gas cylinder).
• Pressure range matching: Ensure the valve’s cracking pressure (minimum pressure to open) is lower than the gas line’s working pressure (e.g., cracking pressure ≤0.02MPa for low-pressure lines). The maximum allowable pressure should exceed the line’s peak pressure by 20% to avoid valve damage under pressure fluctuations.
• Gas compatibility: For oxygen lines, use oxygen-clean check valves (degreased and non-combustible materials) to prevent fire risks; for hydrogen lines, choose valves with anti-static designs to avoid static sparks igniting the gas.
• Installation location: Install check valves near gas cylinder regulators or instrument inlets—this minimizes the backflow path and protects key equipment from contamination.

Regularly test the check valve’s sealing performance (e.g., annual leak testing) to ensure it functions properly, especially for lines carrying toxic or flammable gases.