... pump 2, quality material and improved craftwork 3, for oil drilling purpose 4, we factory. 1, filter assembly used on mud pump ... 2, quality material and improved craftwork 3, for oil drilling purpose 4, we factory. Oil filter is a part of filter assembly (as the ... 3NB and SL series mud pumps. They are widely usedfor drilling rigs.It's the picture of filter assembly. Oil filter for filter assembly used ...