[建] constant-level lubrication, constant-level lubricator
héng dìng yoú wèi rùn huá qì ㄏㄥˊ ㄉㄧㄥˋ ㄧㄡˊ ㄨㄟˋ ㄖㄨㄣˋ ㄏㄨㄚˊ ㄑㄧˋ