Auxiliary hand pump unit and pressure goge for setting relief valves 100, 100, and 12 Auxiliary piping connections for testing SERVICE GATE AND GUARD POWER CABINET GATE CONTROL CABINET A GENERAL 8 L Connect auxiliary piping, hand pump and goges as shown for testing the power and control cabinets 2. New, clean all having a viscosity about that of SAE 10 shall be used for making the tests 3. Special pore shall be used to prevent getting ony dirt or foreign matter in the hydraulic system during testing 4 After completing tests, drain oil, and plug or cap all pipe connections for shipment POWER CABINET 1. For testing the control cabinets the follow ing temperory relief valve and pressure switch settings shall be made a Set the pressure switch to open at OIL TANK SHOP TEST DIAGRAM AND INSTRUCTIONS RING FOLLOWER GATE CONTROL CABINET Pressure goge 2 2200 ps and to close at 1900 psi b With valves B,C,D and open and valve A closed, start the pump and start closing volve V Adjust the relief valve i so that the goge pressure will be 2000 ps when volve Vis fully closed 2. After completing gate control cobinet tests reset pressure switch to open at 2000 psi and reclose at 1700 ps and test switch operation by closing valve A and starting pumps. After switch test, reduce setting of relief valve i to 1700 ps C. SERVICE AND GUARD GATE CONTROL CABINETS 1. With valves H, J, K, L, Mond V closed, valves A,B,C,D,E,F,G,N,O,P,Q and R open, and valves 7 and a shifted to open, start the pumps and adjust unloading valve 2 until pressure goge shows 200 ps Stop the pumps 2 Close volves A and E, open valve H, operate hond pump and adjust relief valve 12 until the pressure gage 3 shows 800 ps 3 To set relief valve 100, reopen valve E, keep valve A closed, close valves P and Q, shift valve 8 to the neutral position, and valve 7 to the close position While operating hond Dump adjust relief volve to a to open when pressure goge 3 reaches 2200 ps To set relief valve lob, shift valve 7 to the neutral position and valve @ to the close position and set relief valve to 2200 ps while operating the hand pump. 4. Reopen volves A, P and Q, leave volve 7 in the neutral position, shift valve 8 to the open position, and stort the pump The pressure gage should read about 200 ps Shift valve 8 to the close position, then close valve H and slowly close volve E With valve E closed relief volve should open and maintain the pressure af 2000 ps After running for enough time to check for leaks, stop pump and reopen volve E. Shift valve to the neutral position, repeat the foregoing operation with valve 7 5. Repeat procedures 3 thru 5 for all cabinets. Leave lost cabinet connected until ring follower control cabinets are tested D. RING FOLLOWER GATE CONTROL CABINETS 1. With volves H, N.O.R and V closed and all other valves open, shift valve 9 to the open position and start pump. The oil should circulate thru the system with pressure goge showing about 200 pai Slowly close volve E until relief valve i opens of 2000 ps and allow pump to run unt system can be inspected for leaks Stop the oil pump 2. Shift valve 9 to the close position Close valve M and open valve E when the pump is started the oil should circulate with pressure goge showing obout 200 ps Adjust pressure reducing valve 3 so that pressure goge 2 reads ops After adjusting valve 3 slowly close valve E until relief valve t opens a 2000 pond check reading on pressure goge 2 to see that it holds af 100 ps with valve M closed 3. Repeat the foregoing tests for the second cabinet 4 Reset pressure switch and relief volve in power cabinet (See porograph @,21 Figure 86.--Ring- follower and outlet gates control--Operating diagrams and instructions. From drawing 456-D-899. The estimated weight of the controls is 17, 000 pounds. (c) Design.--The hoist cylinders and other control parts were designed for a maximum pressure of 2,000 pounds per square inch, but should normally require not more than 1, 500 pounds per square inch to operate the gates. Each pump, running at 1,200 revolutions per minute, is capable of pumping 17 gallons per minute of light hydraulic oil (150 seconds Saybolt universal at 100° F.) at temperatures ranging between 400 and 100° F. for pressures to 2, 000 pounds per square inch. The control and power unit was designed to open or close one outlet gate in approximately 9 minutes with both pumps operating as specified, or one ring-follower gate in approximately 4 minutes. The time required to open or close one gate would be approximately doubled if only one pump is running. The controls are designed to operate one gate at a time. Hydraulic losses in the system were computed by conventional methods. The tank capacity was made equal to three times the pump capacity of the two pumps per minute, plus the differential stem volume displacement with all gates open, plus 10 percent of the total of the two above items. In order to keep the system clean, a fullflow filter was provided in the pump suction line. Valve and switch pressure settings are specified on figure 86. To prevent runaway closing of the gates, a back pressure of 200 pounds per square inch is maintained in the high-pressure drain line by the unloading valve (item 2, figure 86). A pressure reducing valve is provided in the ring-follower gate control cabinet to reduce the pressure used to operate the latches. The main relief valve (item 11, figure 86) is set to open at 1,700 pounds per square inch, but, if it should fail to operate, the pressure switch will break at 2,000 pounds per square inch, and stop the motor. The pressure switch will not remake until the pressure in the system has returned to 1, 700 pounds per square inch. The pressure relief valve (item 10, figure 86) in the outlet gate control cabinet is set at 2,000 pounds per square inch to prevent the pressure in the system from exceeding the design pressure when the oil expands due to temperature change. 69. 96-Inch Hollow-Jet Valves and Controls. - (a) Requirements.-- For outlets 3 and 4 (the two outlets adjacent to and on either side of the outlet pipe manifold centerline), a 96-inch ring-follower gate is mounted at the end of each outlet pipe, with a 96-inch hollowjet valve downstream from the ring-follower gate (fig. 84), as previously mentioned. It is expected that normally the downstream 7. 5- by 9.0-foot slide type outlet gates in outlets 1, 2, 5, 6, 7, and 8 will operate at full gate only, while the two 96-inch hollow-jet valves in outlets 3 and 4 will serve to regulate releases at intermediate amounts. (b) General Description.-- The installation of the hollow-jet valves is shown on figure 87. The assembly of a hollow-jet valve is shown on figure 88. The valves were furnished under specifications No. DS-4186. The nominal size of the hollow-jet valves is 96 inches; this dimension is the inside diameter of both the inlet of the valve and the outlet pipe. Each valve is bolted by its upstream flange to the downstream end of an adapter and discharges horizontally into the river. The valve body is also supported and bolted to brackets at the sides of the valve which are anchored to concrete pedestals. Automatic air vents are provided for both the balancing chamber of the valve needle and the conduit adapter section just upstream from the valve. A drain cock is provided for the balancing chamber of the needle and a drain opening for the inside of the needle support. Just upstream from each of the ring-follower gates a piezometer manifold is installed which connects to a pressure gage. The centerline of the gage is 17 feet above the centerline of the hollow-jet valve. The hollow-jet valve consists of a body and needle. The needle can be moved along the centerline of the body by a jackscrew operated by an electric-motor-driven control unit. When the needle is moved to the upstream end of the valve, it seats and closes the valve. When closed, there is no water in the valve body except in the balancing chamber of the needle. As the valve is opened, water flows past the periphery of the needle in the shape of a cylindrical ring along the inside of the valve body. The splitters which support the needle cut this cylindrical ring into sectors as the water is discharged. Almost full atmospheric pressure is maintained in the interior of the ring inside the valve through the openings between the sectors of water leaving the splitters. The water discharges from the valve in the shape of a hollow cylinder. Figure 87. --Outlet works--96-inch hollow-jet valve installation. El 5429.58 30 TON CRANE € 96 Ring Follower Gate Sta 1869 42 SECTION A-A < Valves E: 5386 00 Each valve has its individual control unit which is located directly above the valve on the operating floor of the outlet house. The unit consists of a reversible electric motor driving a gear reduction unit coupled to the valve control shaft. A position indicator is mounted on the gear reducer and is equipped with limit switches to stop the motor at the ends of the travel of the needle, that is, in the open or closed position. A pushbutton station to operate the motor and a cabinet for its electrical equipment are mounted on the side of each unit. The estimated weight of each hollow-jet valve and its control unit is approximately 120,000 pounds. (c) Valve and Control Unit Design.--The hollow-jet valve was designed for a maximum head of 253 feet, or 110 pounds per square inch. The axial thrust of the water on the needle of the valve is transferred through the body to the outlet pipe or adapter upstream from the valve. The weight of the valve and its contained water is supported by the concrete pedestals. The proportions of the water passageway through the valve have been developed from model and prototype experiments to prevent subatomspheric pressure and cavitation at any valve opening. Eight 2-inch-diameter holes in the upstream face of the needle admit water to the balancing chamber inside the needle. This chamber permits a large percentage of the water thrust on the needle to be balanced by the water in the chamber and transferred directly to the needle support. The maximum unbalanced thrust on the needle occurs with water flowing through the valve and the needle about 20 percent open. The maximum unbalanced thrust on the needle assumed in designing the valve in pounds, is where: Thrust 0.125 awH a = area of balancing chamber in square feet, w = 62.4 pounds per cubic foot (density of water), and H = maximum rated head of the valve, in feet. The control unit of the valve was designed to overcome this unbalanced thrust plus starting friction of the seals and valve parts with a liberal factor of safety. Normal working stresses for the material of any part were allowed in calculating the stress produced by water pressure and the normal running torque of the electric motor. As an additional limitation, the stress at the maximum or break down torque of the motor was not allowed to exceed three-fourths of the yield point of the material in the part. The control unit requires about 7. 2 minutes to open or close the valves. A 7inch-diameter handwheel attached to the side of the control unit may be used on the squared-end shaft of the motor for emergency operation or for final seating of the needle in the valve. Operating instructions for operation of the valve are shown on figure 67. Discharge curves for controlling the quantity of water through the valve are also shown on this figure. The valve handling equipment is shown on drawing 456-D-788. * The lubrication of the hollow-jet valve and operating mechanisms are shown on drawing 456-D789* and figure 67. *Not included. |