I think the term "затвор" (trim) is not correct, because it normally contains a seat as well (in addition to a plug).

Vented closures of packagings shall be replaced by non-vented closures.

kak варианты
затвор гидравлический - water seal
затвор с дистанционным приводом - remote-operated shutter
затвор трубопровода - pipe valve
затвор шлюза - sluice gate, lock paddle
затвор-ревизия (санитарных приборов) trap

it is a seat in our case
e.g.: Forward through a hole pushes away a ball that was blocking the far side of the hole, allowing flow to occur. The motion of the ball compresses a spring.
Backward flow pushes a ball against a hole, preventing outward flow through the hole. A spring expands to help hold the ball in place.
A ball check valve in the open position to allow forward flow and closed position to block reverse flow
A ball check valve is a check valve in which the closing member, the movable part to block the flow, is a ball. In some ball check valves, the ball is spring-loaded to help keep it shut. For those designs without a spring, reverse flow is required to move the ball toward the seat and create a seal. The interior surface of the main seats of ball check valves are more or less conically-tapered to guide the ball into the seat and form a positive seal when stopping reverse flow. https://en.wikipedia.org/wiki/Check_valve

seals

it can be a disk, a ball, or a diaphragm


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Note added at 8 hrs (2019-01-16 20:20:51 GMT)
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https://en.wikipedia.org/wiki/Check_valve