These valve plate gaskets provide a seal for the valves which are of the corrosion-resistant, heavy duty, poppet type. The Stokes Microvac rotary piston pump sets the standard for performance and reliability as the industries most efficient, space-saving design. The Stokes Microvac rotary piston pump has been improved, upgraded, and fine-tuned to deliver even better dependability and productivity combined with minimal maintenance and process downtime.