3. 3 closing butterfly valve required in the process of butterfly valve closing torque is less than the bearing place of friction torque in order to prevent sediment deposition hinder open valve, butterfly valve flow under lower limb closed, hydrodynamic torque M always trend to close the valve, the dynamic water pressure along the flow direction on the valve component p well flow direction, the vertical component of the P1 upwards. is closed, perfectly still, water under hydrostatic pressure on the valve. Due to the great differences, the position of the valve, the effect of hydrostatic pressure center under the center line of the valve, so, for horizontal spindle butterfly valve, the result is to rotate the valve of the hydrostatic torque. In seriyama hydropower station, the butterfly Industrial Valves in the position of the close to the barrier can't normally closed. In each operating mechanism, in the operation of the valve, and the friction of friction torque between the pin shaft. Among them, the valve between the shaft and bearing friction force and torque are the main, its numerical occupy most of the total friction friction torque reduction. According to the design conditions, valve shaft and the friction factor of cast aluminum bronze generally take worship & mu; = 0. 15, so at the highest water head 121. 5 m, the butterfly valve can be automatically shut down by itself configuration of heavy hammer. To appear butterfly valve cannot be automatically shut down the conditions of the phenomenon must be & mu; > 0. 27. So can draw the following conclusion: # 1, # 2 butterfly valve in operation of hydropower station is seriyama 2 years later, in closing appeared different degree of less than seated position. We analysis thinks, appear this kind of circumstance of the reason has the following two points: ( 1) Butterfly valve after more than two years after the operation, the valve may appear between shaft and bearing sediment precipitation, lead to valve clearance between shaft and bearing, bearing friction factor increases. In the process of the closing of the valve, when valve seated position, close to form a pressure difference between upstream and downstream valve, the pressure difference creates a block on the valve shaft closure torque, the drag torque is proportional to the bearing friction factor, when the drag torque is greater than the valve closure torque for the above phenomenon occurs. （ 2) Bearing over a period of time after the operation, the surface of bearing lubrication may be corrosion, bearing wear, friction factor increases, can also lead to the above phenomenon. 4 processing method ( 1) Change the closing butterfly valve operating procedure. At the same time of closing butterfly valve, open the bypass valve, at the end of the valve, then close the bypass valve. Such, can let the butterfly valve in the closed process first, after the water pressure is always balanced, eliminates the upstream or downstream in the process of closing Industrial Valves butterfly valve between the pressure difference, greatly reduces the closing of the frictional resistance, make valve can go smoothly, but also reduce wear on the surface of the bearing lubrication, increase the service life of the butterfly valve bearing. （ 2) Now configure two heavy hammer on the side of the reserve has four (screw hole, can add on a heavy hammer steel plate, and then use screw fastening. Thus increasing the quality of the heavy hammer, the heavy hammer of butterfly valve closing increases torque, make butterfly valve in the bearing friction coefficient increases when also can close smoothly. In the above two methods, if use the second method, butterfly valve can be relatively smooth over a period of time to shut down, but after running after a long time, as the sediment precipitation between valve shaft and bearing and bearing lubrication in further wear and friction factor increases caused friction resistance is more and more big, the butterfly valve is likely to close and can't, even need to change the new bearing. Therefore, in the difficulty of processing the above into consideration and the safe and economic operation of hydropower station, using the modified method of butterfly valve closing process, as shown in figure 1 ( Figure in gray to improve process section) 。 Figure 1 butterfly valve closing process can improve the five practical application seriyama hydropower station butterfly valve closing process after improvement, the closed at the same time open the bypass valve, the valve after water filling. Butterfly valve in the upstream or downstream without water pressure difference to shut down. In this process, the basic eliminates the hydrostatic torque acting on the valve, at the same time, greatly reduce the valve shaft friction torque. Practice shows that the improved butterfly valve operation is stable, normal to close, close the effect is good. At the same time, considering the unit when tachycardia, because of the speed governor main match pressure valve refusing action, need to close the butterfly valve to prevent rapid unit. In this way, in order to prevent due to open the bypass valve when closing butterfly valve unit speed increases, the rapid protection device in the pipe line, the electromagnetic valve and a pipeline to the governor accident. When tachycardia protection device, the accident solenoid valve action, governor quickly toward the closed side of main match pressure valve, close the guide vane, prevent a runaway. 6 conclusion application of the butterfly valve closing process, because before closing butterfly valve, hydraulic balance, after the hydrostatic pressure is lesser, greatly reducing the valve shaft friction torque, also reduced the butterfly valve of the main shaft and the bearing wear and tear, extending the repair cycle of butterfly valve spindle and bearing, but also ensures the stable operation of the butterfly valve, ensure the safe and economic operation of hydropower station. If the use of butterfly valves contain sediment loads large hydropower station, had better not use this kind of belt since the closure of the butterfly valve, for use with the butterfly valve closing device, run after a long time later, as the sediment in the valve shaft and bearing between the precipitation and wear on the surface of the bearing lubrication, the bearing friction factor increases caused friction resistance is more and more big, the butterfly eventually will not close on its own. This will increase the butterfly valve maintenance times, reduce the service life of the butterfly valve, is not conducive to safe and economic and stable operation of the hydropower station.
Collectively, the effect of resilient wedge gate valve on industrial society has been to eliminate os&y valve and drastically reduce the time long associated with os & y valve fire protection.
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