non-return的用法和样例：
词汇搭配
- ball non-return valve 单向球阀
- non return 不返回的
- non return valve 止逆阀,单向阀...
- non return finger 单向指档
- non-return foot valve 止回底阀
- non-return valve 单向活门,单向阀...
- non-return flap valve 止回阀
- double non-return valve 双止回阀
- non-return flap 止回瓣
- non-return trap 止回汽水阀
- non-return device 单向装置
