It is diaphragm type back pressure valve.

背压阀为隔膜式，能调整设定压力。

Casing back pressure valve plays a important role in well cementing operation as a casing accessories.

套管回压阀作为一种简便的套管附件，在固井施工作业中起着重要作用。

According to flow in a different, balanced spool valve the pressure can be pre-pressure, can also be a back pressure valve.

根据流向不同，平衡阀芯所受的压力可以是阀前压力，也可以是阀后压力。

If the engine backfires, the sudden pressure in the intake manifold forces the valve back.

如果发动机回火，进气歧管骤增的压力就迫使阀门向后移动。

Export pump with check valve, it will immediately turn off to prevent reverse flow back high-pressure water pump.

水泵出口装有逆止阀时，它会立即关闭，防止高压水反向流回水泵。