Outlet Structures for Fixed-Dispersion Cone Valves

Following the computation of hydraulic capacity, selection of the most suitable valve and outlet structure for high-pressure regulation of large discharges requires study and evaluation of site conditions and operating requirements. This paper describes three fixed-dispersion cone valve installations which were designed to suit widely varying conditions and requirements at three different locations; Santa Felicia Dam, Vermilion Dam, and Portal Powerhouse, all in California. The site conditions and operating requirements at Vermilion were more severe than at the other two locations, and the Vermilion installation therefore required more detailed design investigations and a more elaborate outlet structure. Hydraulic model tests were made for design purposes and tests of the prototype installation were performed during initial operation, thus providing a considerable amount of technical information. For these reasons, primary attention in this paper is devoted to the Vermilion installation. The installations at all three locations, however, are described to illustrate satisfactory use of fixed-dispersion cone valves for a wide range of site and operating conditions.