When it comes to industrial machinery, besides having a power connection, the second most important aspect is oil. 

Benefits of an open loop system are: significant reduction in heat, and less expensive to maintain.

Benefits of a closed loop system are: smaller tank size, and better efficiency regarding energy used and overall operating costs.

Distribution of oil throughout a machine is done to lubricate the moving parts, and to absorb the heat from friction created by the moving parts. The circulation of oil within the machine can be achieved in two main ways of the hydraulic system:

1. Open Loop Circuit/System (Open Circuit), or

2. Closed Loop Circuit/System (Closed Circuit).

An open loop is the system where the oil passes through the machine and directional valves, and then returns to the oil tank. In the open loop, the system can include relief valve and other controls which direct the oil through the system and then back to the oil tank. Benefits of an open loop system are: significant reduction in heat (oil goes back to the tank), and they are less expensive to maintain (compared to closed circuit) due to the use of affordable fixed displacement pumps. A disadvantage of the open loop circuit is the increased size of the oil tank, necessary to store the large quantity of oil required for the cooling effect.

In a closed loop system, oil goes from the tank, into the pump, through the machine system and then back to the oil pump. The oil does not circulate back to the tank. Due to this feature, a closed loop is usually more efficient because it is not constantly sending oil through the valve when it is not being used. This results in less energy and less fuel being used, providing operating cost savings.

Here at Neumann Dredging, designing, fabricating, and maintaining machinery through regular service is paramount. Refurbishment of machinery such as a dredge also is part of the operation. Refurbishment is done at the stage of the machine’s lifecycle where the wear and tear on the dredge and its parts is such that the options are to either dismantle it and recycle the material, or rejuvenate it to prolong the dredge use for a number of years.