Decision making: systems to close the ducts
During the design of, for instance, a new lock gate layout, the design will often be confronted with various options to solve a single solution. This decision is not always easy to make as it will also impact other decisions down the line, for example, once the decision is made to fill the lock through the gate, the dilemma then arises of which system will serve best to close the ducts.
Almost immediately a team will have a variety of proper concept solutions to the problem. There will be different options for the type of valves as well as for the possible location in the gate.
Obvious configurations are well known and have proven their reliability. There are rotary valves on one hand, which can be round or rectangular. In the first example, technical drawings of a round turning valves are shown. The valve itself is located at a quarter of the width of the gate. On the other hand, one could opt for sluice gates in all their variants. An example of a lifted sluice gate is shown in example 2. A less popular choice are segment valves. To increase the complexity of choice, a wide range of options in terms of the electro-mechanical parts are also available.
Example 1: round turning valves at ¼ of the width of the gate
Example 2 : lifted sluice gate at the side of the lock gate
So, the alternatives need to be weighed against each other. Fortunately, SBE has a suitable decision model to assist in making well-informed decisions. Firstly, various criteria are selected against which the various alternative options will be examined. These criteria are not only chosen on stability reasons, but other aspects are also considered such as: durability, ease of maintenance, overall life cost, safety in handling to name a few. Next, each alternative gets scored on each criterium. This score is not straightforward but relies somewhat on experience and insight. The project boundary conditions or specifications from the client can lead towards the correct score on a criterium for an alternative. Placing al these variables next to each other, delivers a clear(er) image that helps making a good design choice.
One of the main concerns in this process is objectivity. Obviously one can prefer, unknowingly, one alternative to another. And in doing this, one can influence, also unknowingly, the design choice, not always for the better. To avoid, or to control this risk, SBE has developed a good working process.
However, even when you make the design choices as objective as possible and as good as possible, once everything is built and in use, the designer will still notice that some choices could have been better or that an alternative solution would have scored better in reality. But this too has benefits; we gain new insights from it and we can add it to our “lessons learned” file.
For more information about different types of gates, click here.