Le-am intalnit pe toate: flap gate, double flap gate, check gate, check valve, poti sa alegi ce este mai potrivit in context.
Iata exemple:
http://www.electromechindia.biz/home.php?c=2
“Gate, globe and ***check valves*** to start/stop, regulate and to
prevent back flow.”
“Coal Sampling Unit shall be complete with necessary samplers, crushers, ***flap valves***, chutes, hoppers, belt feeders and sample collectors etc. to give samples from any of the two streams running at guaranteed capacity.”
http://specchp.wordpress.com/category/uncategorized/

single/double flap gate
http://www.hitechenterprises.net/bulk-handling-equipment.htm...
single/double flap valve
http://www.electromechindia.net/engineering-items.html
double flap valve
http://www.sulekhab2b.com/patfab/default.htm
valve, flap gate
http://www.machineryandequipment.com/catalogsearch/result/in...