High Strength Synthetic Fixed Disk I. High Strength Synthetic Material Ensure The Fixed Disk Resisting Corrosion From Many Kinds Acids And Strong Alkalines Except Hot Concentrated Nitric Acid.Ii. The Fixed Disk Is Grinded To Have Same Flatness As The Ceramic Moving Disk To Keep Good And Reliable Sealing.Iii. Hermetic Head Faces Construction Has Better Ability To Prevent Damage From Foreign Substance In The Water Operate With Pressure : Reva Valve Uses Two High-flatness Sealing Disks Closely Located Respectively. When Switch The Working Positions, It Could Operate With Pressure. While Some Other Valves Which Uses Soft Sealing Element Like Rubber Parts, It Can't Operate With Pressure. It Needs To Shut Off The Inlet Valve Before Switching.