positive valve的用法和樣例：
例句
- We strongly recommend installing a safety relief valve in addition to the unloader to add more protection from dead-heading.
我們強烈建議，除了減壓器外，再安裝安全卸壓閥來(lái)防止跑空。 - Follow manufacturers instruction regarding the installation and adjustment of any unloader and safety relief valve you choose.
按照操作守則關(guān)于你所選擇的減壓器和安全卸壓閥的安裝和調節指示。
