non-return

not-comparable of a valve

(of a valve) allowing air or liquid to travel in one direction only, and not permitting its return.

Japanese Meaning

一方向のみ通すことができ、逆流を防ぐバルブ（逆流防止弁など）のこと

Make sure the non-return valve is installed correctly to prevent backflow.

逆流を防ぐために、逆止弁が正しく取り付けられていることを確認してください。

Sense（1）

(of a valve) allowing air or liquid to travel in one direction only, and not permitting its return.