A Virtual Tour Through The Dredging Experience In Damen Nieuws

Head line of the virtual tour through the Damen Dredging Experience in Damen Nieuws

One of the things I like about my work is to tell people about it and explain all the delicate details of dredging in a fashion that everybody should be able to comprehend the complexity of moving sand. I am very fortunate to work at Damen as they gave me my own museum to care for: The Damen Dredging Experience1. I’ve discussed several of the exhibits in the Experience on this website already2. Since our last appearance in the internal Damen Nieuws magazine3, the intriguing science of dredging caught the attention of the editorial board. And what better way to share our knowledge on dredging than reporting about it in our Damen Nieuws.

Here on my own website, I already introduced ‘the Experience’ about two years ago, intending to cover the various exhibits regularly. Alas, reality not always behaves as planned. There were so many other interesting items to share, or current CEDA events, or urgent requests from the service department. Well, this publication is a good incentive to continue my coverage of the Damen Dredging Experience.

First exhibit in the entrance hall: a real size DOP pump
First exhibit in the entrance hall: a real size DOP pump (Credit: Judith Korver)

One part of the experience, that does not lend itself for a very detailed explanation is the entrance to the building and the journey to the fourth floor where the experience is located. Immediately after entering the building, you may be overwhelmed by the DOP pump suspended from the ceiling. DOP pumps by themselves are not very large. But, when they are displayed out of place like inside a building, they are still formidable machines. Visitors can be introduced to the general composition of our dredging equipment with this DOP pump: it is basically a small scale dredging machine. It has a suction mouth, a dredge pump and a construction to keep everything together. Same follows for a CSD or even a hopper dredge.

Pictures about the history of The Netherlands and dredging used in the wall illustrations
Pictures about the history of The Netherlands and dredging used in the wall illustrations

Next are four floors with murals depicting topics from the dredging industry. First floor is covering the history of dredging in the Netherlands. How we always had to battle the sea to keep our land dry and tame the rivers for infrastructure. This long history made The Netherlands an excellent breeding ground for knowledge on dredging. The blooming industry is backed up by centers of excellence as the TU Delft, Marin and Deltares. With each of which we as Damen have cooperated to develop our products.

Pictures about the historical relation between Damen and dredging on the second floor
Pictures about the historical relation between Damen and dredging on the second floor

Within the Dutch dredging industry Kommer Damen played a pivotal role in the supply of auxiliary equipment to the big dredging contractors. Eventually, the company De Groot Nijkerk was acquired to also deliver dredging equipment directly.

Pictures with Damen products used in projects around the world
Pictures with Damen products used in projects around the world

Our products have been applied world wide on small and large projects. Everywhere where some wet infrastructure was developed, Damen has supplied some or more equipment. It always makes me proud to see the result of a big project and know that in some (remote indirect) way I have contributed to it.

Pictures illustrating the future of dredging industry
Pictures illustrating the future of dredging industry

The last mural is about the future of the dredging industry. One example is the increasing demand of raw materials. Beginning with the most basic of all: sand for the concrete industry. Increasingly, we see more demand for more exotic materials that are even harder to get: sea floor minerals from the abyss of the ocean. The other example is the ever increasing environmental awareness of society and the attention of cleaning up contamination and creating value for nature. Each of which our DOP pumps form the beginning is excellently purposed.

The Damen Dredging Experience is available for anyone who wants to visit, although it is best to request an appointment with one of our staff4.

Overview of the exhibits in the ‘Damen Dredging Experience’
Overview of the exhibits in the ‘Damen Dredging Experience’

References

  1. Damen Dredging Equipment in Nijkerk Officially Open, DredgingToday
  2. Dredging Experience, Discover Dredging
  3. Our Interview About New Pump Designs In The Latest Damen Nieuws
  4. Contact, Damen Dredging Equipment

See also

Our Interview About New Pump Designs In The Latest Damen Nieuws

Headline of our interview in ‘Damen Nieuws’
Headline of our interview in ‘Damen Nieuws’

Another magazine dropped on my doormat, albeit a digital edition of ‘Damen Nieuws’1. The internal magazine for Damen colleagues. It featured an article with Suman Sapkota and me. Suman is our pump design specialist2 and at a Damen wide R&D convention he presented a poster on his pump design workflow within Damen Dredging Equipment. This caught the attention of the editorial board and we were interviewed on what we actually do for a living. Although we can’t share the exact details of the article or the poster, it is still an interesting message that we can highlight here.

Pump design workflow (inspired by Suman Sapkota)
Pump design workflow (inspired by Suman Sapkota)

The design of a dredge pump is based on the required specifications(1). The most important properties of the pump are: efficiency, NPSH, wear and ball passage. The first important property we try to fix is the ball passage3. We do use our own geometry generator(2) that assist us in creating a pump with a big ball passage. Unlike normal pumps, dredge pumps have to cope with debris and boulders that have to pass the impeller. The bigger chunks that can pass, the more uptime the dredge will have. Once we are satisfied with the geometry, we feed this through a file format converter(3). The resulting 3D file can be used on several platforms. This will enable us to create the digital solid for the engineering4, but it also gives us the negative volume, also known as fluid. Then to do mathematical operations on the digital fluid, we have to divide the volume into tiny cells. This process is called meshing.(4) When the mesh is available, the fluid flow through the mesh can be simulated with computational fluid dynamics.(5) All the fluid properties of every cell are calculated and the results are shared with the adjoining cells. This can be repeated until all properties of the cells don’t change very much anymore, a stable solution. Integrating all the properties of the cells give the resulting performance of the pump.

Balancing the four dredge pump performance properties
Balancing the four dredge pump performance properties

The estimated performance can be evaluated against the four properties.(6) The head times the capacity divided by the power required will give the efficiency. That is one of the items we wanted to know, as it relates to how much fuel will be consumed. The other parameter obtained from the CFD is the NPSH, or roughly: the suction performance. Wear cannot be estimated yet, but we are working on that2. Although the calculated turbulence might give a clue what wear to expect. If the properties are not satisfying our requirements we make an iteration in the geometry for improving the performance. However, changing the geometry will usually result in a smaller ball passage. If the parameters are OK to our requirements we have a pump design.(7) Manufacturing it is a completely different game.5

The design process of the dredge pump takes quite some effort and we are continually looking to improve the workflow6. Eventually we would like to be able to cater for all special requirements each individual customer might have.

Working for a dredge manufacturer, I am happy we design and produce our own pumps. It gives us the confidence, that when we supply dredges, they are as we like them to be. Another benefit is in discussions with the customer. It is easier when we can sit at the table as experts on their equipment assit them in finding a solution for their dredge.

Pump experts immersing themselves in checking the design of their pumps
Pump experts immersing themselves in checking the design of their pumps

References

  1. Damen Nieuws, Juni 2020, Damen
  2. Graduation Suman Sapkota: Where wear parts were worn down, Discover Dredging
  3. On The Relation Of Maximum Ball Passage And Recirculation Losses In Dredge Pumps, WODA
  4. Graduation Of Carsten Markus: Designing And Casting Of Impellers
  5. Don’t Play Games With Your Wear Part Planning
  6. Innovation, Damen

See also

HYDRO 2018 Gdansk: Selecting A Dredge For Your Reservoir Maintenance

Barrage du Ksob, M’Sila, Algeria with a DOP dredge 350

This week, I am here in Gdansk for a presentation on the HYDRO 2018 Conference1 and assist at the Damen booth at the corresponding exhibition. The paper and the presentation are already prepared and I am very excited to do the presentation, but I can’t wait till tomorrow and I like to share the story now, already. So, you, as my favourite audience, will have my personal spoiler after so many teasers have been floating around2,3,4.

General modes of siltation at the usual location in a reservoir

The thing is, dam maintenance and reservoir restoration is something already long on my attention list. Back already in 2008, I wrote a paper on this subject for the CEDA Dredging Days5. Over and over we’ve conveyed the message on various platforms, that dredging might be a viable solution for sedimentation problems in reservoirs. Usually, the solution by dam owners and operators is to flush, sluice or store the sediment. This looks horrible from a dredging perspective, but it is also to the environment. You either smother or starve the downstream river with sediment. As a right minded dredge enthusiast, you see many possibilities to dredge such a project. Immediately we can identify what dredge to use on which location for which purpose.

Selection of applicable dredges for reservoir dredging

If you are very close to the dam and the length of the discharge line allows it, you might even not need a dredge pump. (No wear parts!) It is a so called siphon dredge. But as soon as there is some further transport involved, either distance or uphill, you need a dredge like a cutter suction dredge or a DOP dredge. For even further discharge, you might employ a booster for increased discharge pressure. If the distance becomes very far, you might have to resort to grabs and barges.

Water injection dredging principle and example (this example would be too big for a common reservoir)

As an intermediate solution you might even consider using a water injection dredge. Usually the reservoir is in the mountains and a bottom gradient will be present, enabling the required gravity flow. The actual dredge should have created a silt trap where it can collect the inflowing material from the water injection dredge. Than it can handle the material as usual.

Alternative uses for the dredged sediment a) silt farming as fertile additive b) gravel extraction for concrete

Off course, the dredged sediment belongs to the river and the best thing would be to gradually release the sediment after the dam. But there might be conditions, where it is beneficial to extract the valuable fraction of the sediment and use it for agriculture or as aggregate in the construction industry.

Dredge selection diagram for reservoirs

We noticed, that it is often difficult to convey to dam owners and operators which dredge to select for which job. Sediment is seen as a liability and not as an asset and they rather neglect issues associated with the sediment. So, I made an attempt to have a plain and simple selection diagram. That is the core of my manuscript. But my objective is, that we will see many beautiful dredges contributing to a sustainable and viable operation of hydropower dams and reservoirs.

New DOP dredge family

References

  1. HYDRO 2018: Progress through partnerships, Hydropower and Dams
  2. LinkedIn Teaser, Saskia den Herder
  3. Damen: Spotlight on Hydro Power Dam Maintenance
  4. LinkedIn Teaser, Olivier Marcus
  5. Multi Functional Small Dredging Solution For Maintenance Of Deep Irrigation Reservoirs And Hydro Power Dams, CEDA

See also