The main variations for this valve are the methods of sealing the perimeter of the disc in its closed position. The simplest variation is to use an elastomeric lined bore which is an interference fit on the disc. The other variations are based on offsetting the disc plane from the axis of rotation allow the disc to close against a circular face seal such that the fluid pressure increases the seal effect. Metallic seals are available allowing the valve to be used for a wide range of fluids at high temperatures

The main variations for this valve are the methods of sealing the perimeter of the disc in its closed position. The simplest variation is to use an elastomeric lined bore which is an interference fit on the disc. The other variations are based on offsetting the disc plane from the axis of rotation allow the disc to close against a circular face seal such that the fluid pressure increases the seal effect. Metallic seals are available allowing the valve to be used for a wide range of fluids at high temperatures