Regulating valve for main water supply bypass
| Type | Regulating Valve |
| Model | T668Y-4500LB, T668Y-500, T668Y-630 |
| Nominal Diameter | DN 300-400 |
It is used for main water supply bypass pipe of 1,000MW supercritical (ultra-supercritical) unit boiler for regulating water supply flow.
- The valve is straight type structure, medium flow direction is flow type and sealing surface of the valve seat is far away from final step flash evaporation zone to guarantee service life.
- The valve body and bonnet adopt forged steel structure with high strength to better meet strength requirements under high temperature and pressure.
- It adopts removable valve seat structure and the valve seat has Stellite No. 6 alloy build-up welding on its sealing surface.
- The valve disc adopts balanced structure and sealing surface undergoes high frequency quenching; upper and lower cavities of the valve disc realizes pressure balance through a connecting pore. In this case, the valve can be closed by a drive device with less thrust.
- Throttle component of the valve core is designed to adopt 6-layer cover 5-step pressure reducing structure to scatter single strand fluid with high energy into multi-strand fluid with low energy to reduce speed and noise. Step-by-step pressure reduction is realized by aperture dislocation to eliminate cavitation. The final step sleeve makes fluid depart along tangent line direction and face inner cavity of the valve body indirectly to reduce scouring to the valve body.
- Middle flange sealing adopts dual-sealing structure of wave tooth composite gasket and elastic energy storage ring, making sealing more reliable.
- Under the working condition of small flow and big differential pressure, multi-step sleeve throttle is adopted and step-by-step pressure reduction is realized by dislocation arrangement of aperture with non-equal diameter to control medium flow speed strictly and reduce of impact of cavitation and flash evaporation on valve. Under the working condition of big flow and small differential pressure, single-step window is adopted for pressure reduction to ensure flow capacity of the valve.
- Regulation characteristics is improved equal percent, capable of control medium flow accurately to achieve good regulation performance.
- The valve can be equipped with optional electric or pneumatic mechanism to realize rapid opening and closing and three-protection.
