Going against the flow

Erwin Bijvoet
Erwin Bijvoet
06 July 2017

The journey for new technologies is always an exciting one. This was certainly the case with IHC’s Plumigator overflow. We chose to develop this solution in response to the challenges being faced by our dredging customers. 

In particular, we wanted to tackle the issues caused by the overflow process. However, the results surpassed our expectations. First, let’s go back to the origins of the project.

Familiar challenges 
During the overflow process, the aim is to remove excess water from the hopper. After all, this allows you to haul more payload. However, with a regular overflow, the excess water can flow freely. This results in a chaotic process with large quantities of air mixed in the flow. 

When released from the vessel, some of this mixture enters the inlets, such as the auxiliary pumps. This can result in loss of performance and even component failure. 

Due to the increased presence of air, the mixture ‘floats’ to the surface. This creates the characteristic plume, which has an adverse effect on the local ecosystem. 

Flow dynamics
By further understanding the plume, we became more aware of the requirements during overflow. Through controlling these processes, we realised it was possible to limit the amount of air in the mixture. This would also reduce the dispersion of the plume. 

We put our ideas to the test in the lab to understand the flow dynamics. The most promising valve-controlled system was then tested on an existing vessel. Our findings underpinned the assumptions we’d made, and it was an important milestone. 

A new solution is born
In the end, it was smart flow distribution that did the trick, with air practically eliminated from the system. We engineered a solution containing no moving parts, that was self-regulating and also compliant with DR68. The icing on the cake was that it could be retrofitted to any existing overflow. 

We’ve already successfully done this with one unit and the feedback’s been positive. Its operators say that the amount of air resulting from the overflow process is essentially eliminated, and the plume has been reduced significantly. An exciting journey indeed.