Double disc
<img src="https://eng-calculations.com/SVG/Hydraulic_engineering/Valves/Double disc.svg" alt="Double_disc" title="Double_disc">
https://eng-calculations.com/SVG/Hydraulic_engineering/Valves/Double disc.svg
<img src="https://eng-calculations.com/SVG/Hydraulic_engineering/Valves/Double disc.svg" alt="Double_disc" title="Double_disc">
https://eng-calculations.com/SVG/Hydraulic_engineering/Valves/Double disc.svg