For the valve with the metal to metal seal,there is grease injector outside of it,grease gets into the sealing face through the injector and the seat ring to have the valve up to null leak.是什么意思_For the valve with the metal to metal seal,there is grease injector outside of it,grease gets into the sealing face through the injector and the seat ring to have the valve up to null leak.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句