Non-Return Valves

Non-Return Valves or Screw Tips are an integral component in providing precise part weights in the injection molding process. The purpose of this device is to allow plastic flow in one direction and prohibit it in the other direction. There are two primary designs that have evolved over the years, the sliding ring design and the ball check or poppet design. These two primary designs have iterations such as three, four or five piece Sliding Ring constructions and they are manufactured out of different materials to withstand adhesive and abrasive wear as well as corrosion. Md Plastics has developed and patented NRVs that deliver improved part weight distribution and have extended wear life. We are currently marketing the two primary Sliding Ring and Poppet designs as well as our proprietary Posi-SealTM and TM (patent pending) designs.