The large offset mouth is applied instead of elbows. It not only saves materials, but also reduces the drainage resistance. It lays a foundation for doing well the gas drainage.

现改用大偏口代替弯头，不仅节约材料，而且降低了抽放阻力，为做好瓦斯抽放工作打下了坚实的基础。

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The large offset mouth is applied instead of elbows. It not only saves materials, but also reduces the drainage resistance. It lays a foundation for doing well the gas drainage.

现改用大偏口代替弯头，不仅节约材料，而且降低了抽放阻力，为做好瓦斯抽放工作打下了坚实的基础。

youdao