This check valve is typically used between a regulator and a lubricator to supply an unlubricated air supply. The check valve keeps lubricated air from getting into the unlubricated lines.

SMC's new AC series of modular type F.R.L. unit is available in 4 sizes and is interchangeable with the existing modular type AC line. The element and bowl on the AW and AF series is now one-piece, making element replacement easier. Required maintenance space has been reduced by as much as 46% on the AF series, depending on the body size. Bowls on size 30 or more are now covered with a transparent bowl guard, completely protecting them from the environment, and making the inside visible from 360 degrees. Check valve with intermediate air release port. It can be easily installed to prevent a back flow of lubricant when redirecting the air flow.