preventer

A strainer is recommended to be installed ahead of the backflow preventer to prevent the fouling of the check assembly and resulting spillage from the valve during repressurization.

建议在回流阀前安装一个过滤器，于回阀总成受到污染导致这种阀门在再增压生泄漏或溢出。

While underbalance drilling spreads greatly, rotating blowout preventer, as a kind of high technical product, is the crucial equipment to control well pressure.

国内欠平衡钻井普遍实施,要用到的旋转喷器是关键设备,技术含量高。