Sealing arrangement

A pneumatic valve comprising a valve body with an interior wall defining an interior chamber and a metering piston movable within said interior chamber and defining an exterior surface, one of said interior wall and said exterior surface providing a groove-shaped recess and including a sealing ring therein,

• said groove-shaped recess in cross-section defining a mouth, a bottom, opposed shoulders located between said mouth and said bottom, first opposed lateral walls that extend from said mouth to said shoulder and second opposed lateral walls that extend from said shoulders toward said bottom, said second opposed lateral walls being spaced by a width which is 10 to 20% larger than a width spacing said opposed shoulders, and
• said sealing ring being made at least in part of an elastic material and defining in cross-section a holding region at a first end, an opposite second end portion defining a sealing edge, and a holding edge therebetween, said holding region fitting between said second lateral walls of said recess, said holding edge contacting one of said opposed shoulders of said recess, and said second end portion extending between said first opposed lateral walls and outwardly of said mouth so as to contact a second of said interior wall and said exterior surface, an end of said holding region facing said bottom of said groove-shaped recess defining a width which is no greater than a width of said second end portion.