Hydropower Station DSSD Pressure Regulating Valve

Hydropower Station Pressure Regulating Valve/ Pressure Regulator Price

 
1.Product Introduction

Pressure regulating valve is long pressure diversion tunnel of a hydropower station safety equipment, in general, when the pressure water diversion pipe Σ LV/H is more than 15 ~ 30, to set up the surge tank, due to large surge tank construction quantities, the construction period is longer, the pressure regulating valve instead of surge tank, can save investment, shorten the construction period.

2.Application

The main body of the pressure regulating valve is arranged horizontally, that is, the center lines of the water inlet pipe and the oil cylinder are parallel to the ground, mainly composed of the valve housing, the valve plug, the main oil cylinder, the guide oil cylinder, and the air supplement valve.

3.operating principle

The control system of TFW pressure regulating valve adopts full hydraulic control and operation. The guide vane servomotor and pressure regulating valve are simultaneously controlled and operated through special main pressure valve and other components installed in the governor. Its working principle is as follows:

(1) When the load of the unit remains unchanged, the main pressure valve piston is in the middle position, and the pressure oil P1 from the governor enters the closing chamber of the main oil cylinder of the pressure regulating valve through the orifice A. At this time, the oil pressure of the pressure regulating valve closing chamber is P1. =P2, the opening chamber is open to drain oil. Since the oil pressure in the closing chamber is greater than the water thrust on the valve disc of the pressure regulating valve, the pressure regulating valve is in the closed position.

(2) When the unit reduces the load (about 15% of the rated output of the unit), because the upward displacement of the piston in the middle valve disc of the main pressure distribution valve is less than the overlap amount S, only a small amount of pressure oil P1 passes through the orifice at this time A enters the closing cavity of the guide vane servomotor and slowly closes the guide vane. At this time, the pressure drop △P formed by a small amount of pressure oil through hole A is small, and the oil pressure in the closing cavity of the pressure regulating valve (P2=P1-△P) can still be Maintain the pressure regulating valve in the closed position. At this time, the pressure regulating valve opens the cavity to discharge oil. Therefore, when the load reduction is not large, the pressure regulating valve does not act and the guide vane servomotor closes slowly.

(3) When the unit instantaneously dumps a large amount of load (more than 15% of the rated output of the unit), the upward movement of the piston in the middle valve disc of the main pressure distribution valve is greater than the overlap amount S, and the pressure difference △P on both sides of the orifice increases , P2 is reduced, and the opening chamber of the main cylinder of the pressure regulating valve is connected to the pressure oil P1, the pressure regulating valve opens quickly, and the pressure oil discharged from the closing chamber of the pressure regulating valve plus a small amount of pressure oil through the A hole flows to the guide vane servomotor to close The cavity quickly closes the guide vanes. Since the same main pressure valve is used for control, the rapid opening of the pressure regulating valve and the rapid closing of the guide vane are synchronized and synchronized.

(4) When the load of the unit increases, the piston of the main pressure distribution valve moves down, and the pressure oil P1 directly enters the opening cavity of the guide vane servomotor (not restricted by the A hole), the pressure before and after the A hole is equal, and the pressure regulating valve closes the cavity oil pressure No change, the opening chamber is open to drain oil, so the pressure regulating valve is still in the closed position.

(5) "Segmentation device": When the pressure regulating valve starts to open quickly, the oil discharge of the guiding cylinder is restricted by the orifice C and the oil pressure rises rapidly, forcing the oil pressure check valve to overcome the oil pressure and open, so In the process of rapid opening of the pressure regulating valve, the pressure oil in its closing cavity only partially closes the guide vane servomotor, while a small amount of other pressure oil is continuously drained through the regulating valve D, so the opening speed of the pressure regulating valve is faster than that of the "segment device" "It speeds up when it is not put in. When the regulating valve opens in advance to the position restricted by the limit ring and stops (at this time the guide vanes have not been fully closed), the oil pressure of the guiding cylinder disappears, and the oil pressure check valve quickly closes automatically. At this time, only a small amount of pressure oil from hole A slowly continues to close the guide vane servomotor, so that the guide vane is closed in two sections. Therefore, the size of the opening of the regulating valve D can directly control the inflection point position of the guide vane section closing. After the guide vane is closed, when the speed of the unit decreases to the normal speed, the main pressure control valve returns to the middle position, the main oil cylinder of the pressure regulating valve opens the cavity to discharge oil, so the pressure oil P1 slowly closes the pressure regulating valve at the specified speed through hole A .