However, a more closed system, open and complex systems, because no fuel tank, oil cooling and filtering the disadvantaged.
但闭式系统较开式系统复杂，因无油箱，油液的散热和过滤条件较差。
2
Meanwhile, using a filtering device to recycle the systemoil to keep it clean is also available.
同时，也可用滤油设备对整个液压系统进行循环过滤，净化液压系统的油液。
3
These system include filteringsystem for crude oil entering, filtering and cooling system for hot oil, filtering and cooling water circulating system for reduction gearbox of the drilling motor.