Penstock Valve Seal Engineering and Upgrade at the City of Calgary’s Glenmore Dam

The City of Calgary’s Glenmore Dam has two 12 ft diameter penstock discharge of water (DOW) valves to control the water level of the Glenmore Reservoir. These valves and penstocks also allow water to flow to three turbine pumps, and to maintain water flows to the Elbow River. Both valves date from 1933. The work was performed during the period of fall 2007 through to the winter of 2009 in the winter months when the risk of high river flows was minimal. Both of these valves were removed from service one at a time, completely upgraded and repaired, and had a new seal system engineered and installed on both the penstock valve bodies and on the valve discs themselves. This was the first time that the valve discs were removed from the penstock since they were installed as new. Both valve actuators were rebuilt at the same time as the valves. The valve discs had extensive cracking around the plug holes that were repaired and a bronze seal strip was welded onto the outside diameter. The penstock valve body seal was originally made of lead; this seal was removed and a new stainless steel seal was welded in place in sections. The valve discs sit at 10 deg from vertical in the fully closed position, and hence they are elliptical in shape; the seal is on a 10 deg angle in the penstock valve body as well. The valve discs were then machined at a 10 deg angle to match how they seat. The penstock valve bodies were machined with a BB8100 – 8 in line boring machine. The final clearance between the valves and penstock valve bodies was between 0.001in and 0.015 in, resulting in very little leakage.

Towers, A., S. Dold, H. Costello, W. Dumont, K. Illerbrun, A. Hughes, D. Campbell, G. Stranks, L. Courage and S. Baytaluke. 2010. “Penstock Valve Seal Engineering and Upgrade at the City of Calgary’s Glenmore Dam,” in: HydroVision 2010, Pure Natural Energy, Charlotte, North Carolina, July 27-30, 2010. Tulsa, Oklahoma: PennWell.

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