Tool Deployment System: The Hydraulic Manifold Assembly
The MPS tool deployment system (Hydraulic Manifold Assembly) is central to the efficiency of the Jetter Arms. Tests have shown that the angle at which the Jetter Arms are presented to the soil is crucial to efficient trenching. It is therefore necessary to maintain the jet angle during deployment which means that the tool must be deployed vertically into the soil.
To this end the design utilizes two deployment guides, set at the correct angle to the seabed, down which the Jetting Arms slides, driven by a set of hydraulic cylinders.
A range of different length tools can be supplied to optimise trenching in different soil types. These range from a 1m tool to a 3m tool, the 3m tool being fitted with a valve to “turn off” the upper jets, thereby concentrating the water flow to the lower jets when trenching in stiff soils.
To minimise vehicle height the 3m tool is stowed horizontally under the vehicle. It is rotated into the vertical by software control, encroaching minimally into the seabed as it does so. It is then deployed into the soil down the guides to the required depth. Shorter tools are simply stowed by raising them up the guides.
As the jetter arms are operated in abrasive soils, wear plates will be installed on the forward and inside surfaces of the jetting arms. These wear plates provide a smooth surface for the product, and are replaceable when depleted. To maintain robustness, guards are mounted on the jetting tool to protect position sensors.
Jetting tool information is provided by sensors mounted directly to each arm. Individual arm width, jetting tool deploy angle, and bottom nozzle depth are available to allow operators to monitor and adjust tool position during operations.
A jetter pump head pressure sensor is also provided to allow operators to monitor and control system performance. Load cells indicating both forward/reverse and lateral loading on the jetting arms are provided.
Surface alarms alert the operator if the jetting tool is being overrun (higher than normal forward loads) or if the vehicle is crabbing (side loaded) along the jetting line of action.