OUTLET WORKS

LIST OF DRAWINGS

the water pressure inside the gate. The hoist is connected to the gate leaf with a corrosion-resisting stem. Bronze seats and seals are used on the gate body and leaf to provide a low friction and rust resisting, slidin surface for the leaf. The maximum load on the sliding surface of the leaf is approximately 890 pounds per square inch.

The allowable unit design stresses for the various materials used in the ring-follower gates were based on the yield point and ultimate strength of the material. The smaller of the following tensile stresses was used:

(1) Rolled or forged, steel and monel--40 percent of the yield point or 25 percent of the ultimate, except for bolts where the design stress was limited to 25 percent of the yield or 16. 5 percent of the ultimate.

(2) Cast, steel and monel--33 percent of the yield point or 20 percent of the ultimate.

(3) Rolled, brass or bronze--33 percent of the yield point or 16.5 percent of the ultimate.

(4) Cast, brass or bronze--33 percent of the yield point or 16. 5 percent of the ultimate.

(5) Cast iron--12. 5 percent of the ultimate.

The compressive stress was the same as the allowable tensile stress for the various materials, except for cast iron which was three times the allowable tensile stress.

The shear stress was 0.6 of the allowable tensile stress for the various materials, except for cast iron, which was equal to the allowable tensile stress.

86. Controls for 84-Inch Ring-Follower Gates and 84-Inch Jet-Flow Gates. (a) Requirement.--Two control cabinets are installed at Trinity Dam; one is located in the control house of the outlet works to operate the two 84-inch ring-follower gates installed in the control house, and the other is located in the auxiliary outlet gate chamber to operate one ring-follower gate and one jet-flow gate installed therein. Controls for the gates are manually operated and only from their respective control cabinets. Direct reading-position indicators are located on the hoist of each gate.

(b) General Description. --Figures 77 through 80 show the arrangement and details of the controls. Also see invitation No. DS-5075. Each cabinet is of steel construction and houses a control system that operates two gates. Each cabinet contains two oil pumps each having a rated capacity of 7 gallons per minute when pumping oil at 2, 000 pounds per square inch; two 10-horsepower, 440-volt, 3-phase, 60-cycle electric motors; and hydraulic and electric controls. A 145-gallon oil supply tank is located on top of the control cabinet to maintain the minimum oil supply level above the high point of the control system. For operating details, see figures 79 and 80. The estimated weight of the assembled control cabinet including the oil tank is 4, 400 pounds.

(c) Design. --The control system is designed for a maximum oil pressure of 2,000 pounds per square inch, and a normal operating pressure of 1, 800 pounds per square inch. Under normal conditions, approximately 10 minutes are required to open a ring-follower gate and approximately 11 minutes are required to close it. Approximately 2 minutes are required to open the jet-flow gate and approximately 3 minutes are required to close it. Twice this amount of time is required if only one oil pump is operating.

The hydraulic control system normally operates a ring-follower gate with the water pressure balanced on both sides of the leaf, but both the control system and gate are designed for emergency closure with full flow through the gate under full reservoir head. A mechanical latching device is provided on the upper cylinder head to hold the ring-follower gate in the open position. The jet-flow gate is used for regulation, and the hydraulic system is designed to operate or hold the gate in any position under any reservoir head by confining oil under the hoist piston.

87. 84-Inch Hollow-Jet Valve. (a) Requirement. --Two 84-inch hollow-jet valves are located in the control house of the outlet works. The valves are bolted to the discharge ends of the two 84-inch outlet pipes, and are used to regulate the flow of water through the outlet works (fig. 74). Each valve is controlled by a hydraulic cylinder and may be operated at any reservoir head. The valves can be held closed or at any intermediate position by confining oil in the closing chamber of the cylinder.

(b) General Description. --Figures 74 and 81 show the arrangement and details of the hollow-jet valves. Also see invitation No. DS-5091. The hollow-jet valve is a welded and cast-steel structure and consists of a cylindrical body, a needle, plunger, and hydraulic cylinder as shown on figure 81. The axis of the cylinder is located on the longitudinal centerline of the valve and is positioned in the body by six radial splitters. The plunger-operated needle has a travel of 29-1/2 inches from fully open to fully closed position and moves upstream to close the valve. As the valve is opened, water flows past the periphery of the needle in the shape of an annular jet along the inside of the valve body. The splitters which support the needle cut this ring into segments and the water is discharged from the valve in the shape of a hollow cylinder made up of six separate jets. The estimated weight of each valve is 80, 000 pounds.

(c) Design. --The hollow-jet valves are designed to operate under water pressures up to 210 pounds per square inch and can discharge approximately 4, 600 second-feet at full reservoir head. The weight of the valve will be carried on the valve supports, and the axial thrust of the water will be transferred through the connecting flange of the valve to the outlet pipe. The proportions of the water passage through the