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Over the past decades, nuclear density meters have become widely used on board of dredging vessels worldwide. Not because they are particularly highly rated or cost-efficient – their disadvantages are well known – but mostly because of the lack of viable alternatives. Now Dutch company Alia Instruments is challenging the status quo with an innovative non-nuclear density meter that could very well become the new industry standard. “The idea to design a non-nuclear meter, was inspired by our experience as engineering consultants for our sister company Imotec,” explains Jan Peters, one of Alia’s founding partners. “On board of our clients’ dredgers we would invariably spot a nuclear density meter and more often than not crews had their reservations about working with them: the radiation made them feel uncomfortable.” Companies voiced their own concerns, Peters adds, “They dread the added costs of RSO certified personnel, on-board safety precautions, and proper nuclear waste handling.” More importantly, the inherent lag – of often more than 30 seconds – in this gauging method precludes accurate real-time control of the dredging process.

Accurate real-time control of the dredging process

This results in loss of production, a costly deficiency that – as dredging executives know – can add up quickly. Yet, afraid to hamper the continuity of their operations many in the industry tend to stick with what they know, according to Peters. “In order to make their decision to switch with more confidence, we engineered our meter’s design to be as straightforward as possible. Meaning: an in-line density meter that is robust and exceptionally easy to use and install. A non-nuclear alternative that offers clear, immediate, and continuous readouts.” “The aim was to keep our gauging method as simple possible,” Peters explains, “therefore it was decided early on in our research process that our design would make use of Newton’s second law of gravity. This method guarantees that the output data is immediate and accurate regardless of pipe-diameter or slurry density.” In order to yield accurate results, all non-gravitational forces working on the device need to be mitigated. Mechanical methods to achieve this have been tried. However, especially under arduous conditions – a dredger rolling on ocean waves for instance, or pipes vibrating under high pressure deep underground – these solutions have proven to be unreliable and needlessly complex. Peters, “Therefore we opted for what we thought was a much simpler and more efficient approach. By building in an accelerometer – technology found in anything from smartphones to drones these days – we designed a meter that can calculate and neutralize any interfering forces simultaneously.” Coming pre-calibrated, Alia’s new meter can be simply installed in-line and is easy to use and truly versatile. It can even be placed in conjunction with an existing flow meter. Its non-proprietary output signal can be read by standard pods and processed by all existing software applications.  

Simple design

Peters is convinced that with the dredging industry increasingly being global, a new industry standard needs to be widely compatible and open. Because of their simple design and the use of standard, off the shelve components, Alia’s non-nuclear devices can be implemented and used all over the world, in any context, and serviced by local engineers. Peters: “Our engineering is the result of an innovative reconfiguration of trusted elements, technology that has proven itself in countless applications and conditions. This versatility means that besides dredging, Alia Instruments is also active in various other markets, such as the well servicing industry, mining, and tunnel construction.”  

Control the dredging process

Feedback from current users of the meter has been positive, which shouldn’t come as a surprise since Alia Instruments is offering multiple solutions at once with their non-nuclear technology. First, they offer a viable alternative to the still widely used nuclear devices, addressing safety and environmental concerns while eliminating the costs of RSO certifications and the disposal of hazardous materials. Secondly, their innovative design mitigates most, if not all of the gauging deficiencies inherent to using radiation for determining slurry density. No longer will very low or high densities lead to inaccurate data. No more lag in the data output. In providing immediate, and full-volume density values, Alia Instruments enables engineers to control the dredging process from one moment to the next, decreasing water usage and increasing production.