Gearing is generally applied to valves to make operation easier. The gearing may be of the spur, bevel or worm type - any of which may be applied to Velan valves.是什么意思_Gearing is generally applied to valves to make operation easier. The gearing may be of the spur, bevel or worm type - any of which may be applied to Velan valves.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句