Birch, Stewart, Kolasch & Birch
Inline type check valve
 An inline type check valve having a tubular body, a mushroom or umbrella-shaped piston axially, movably mounted in the tubular body, a coil spring disposed behind the piston in the body, and a hollow disk axially removably fixed to the body. Both the body and the disk made from a synthetic resin reinforced with fibers and resiliently hooked in each other. The piston has its periphery provided with a plurality of grooves to increase the cross-sectional area for fluid flow through the valve. 
Nippon Piston Ring Co., Ltd.
F F Y Y
F16K F16K Y10S Y10T
inventional inventional additional additional
Yasuo Tetsuo
Suzuki Masuyama