Sigma Design recently completed a project that was in response to a very challenging problem. They were approached by a customer to design a platform to be used for hydroelectric turbine maintenance by the Army Corp of Engineers. The constraints seemed to be quite a challenge. The platform was to be suspended from the underside of the turbine in the 26 foot diameter chamber below, where water exits after powering the turbine. Workers then could stand on the platform to inspect or repair the turbine blades. However one constraint made this design particularly challenging. The only way to access the chamber was through a 24” x 30” manway. This meant that the platform had to be shipped to the customer in basic parts, passed through the doorway, and assembled from inside the chamber.
A problem like this requires the engineering expertise that Sigma prides itself on.
After thorough dialogue with the customer on design options, Sigma developed a modular platform that could be broken down to basic pieces and passed into the chamber. Aluminum beams and plate were chosen as the primary materials of construction to keep weight down for the workers handling the pieces. The platform was designed and assembled in CAD and very thorough FEA was applied to look at how stresses would affect the platform under desired workloads. The result was a detailed design package delivered to the satisfied customer. It was time to start the fabrication process, which Sigma completed in-house at their Middlesex, New Jersey facility.
Another challenge arose when it was time to assemble and test the platform. It had to be assembled, suspended in a state the replicates mounting points in the turbine chamber, and loaded with over 10,000 lbs to load test it. Sigma got to work and devised 5 fixtures, each replicating the mounting points in the turbine chamber. The platform was then assembled, suspended from the 5 fixtures, and loaded with water bags to achieve the required load to test the platform for safety. Sigma set up cameras and brought a workstation to the test area to record deflection data, as well as present to the customer remotely as a “Digital FAT”.
Water Bags used for Load Testing
The result was another Sigma success and another satisfied customer. Do you have a design challenge that you need another set of eyes to look at? Please give us a call 732-629-7555 or send us a request at firstname.lastname@example.org