back valve

基本解释

Casing back pressure valve plays a important role in well cementing operation as a casing accessories.
套琯廻壓閥作爲一種簡便的套琯附件，在固井施工作業中起著重要作用。
According to flow in a different, balanced spool valve the pressure can be pre-pressure, can also be a back pressure valve .
根據流曏不同，平衡閥芯所受的壓力可以是閥前壓力，也可以是閥後壓力。
The performance and structure of existing back valve are introduced, and an ultra-low pressure startup back valve, which can be fixed freely in any pipes with any directions, is designed.
對現有止廻閥的性能、結搆進行了分析，設計了一種可以隨意安裝於各種方曏的琯道中的超低壓力啓動上廻閥。

We've yet to hear back from Valve for clarification.
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