TBV / PRDS — steam turbine bypass valves and pressure reducing and desuperheating valves, up to 270 bar, up to 650 °C
TBV valves divert steam around the turbine during start-up, shutdown and emergency trip, and PRDS valves reduce steam pressure and temperature for the consumer. Steam parameters up to 650 °C and 270 bar, in-line or angle body. For thermal and CHP plants, combined-cycle plants with heat recovery boilers, and geothermal, solar and nuclear stations.
- Purpose
- TBV: diverting steam around the turbine during start-up, shutdown, emergency trip; PRDS: simultaneous reduction of steam pressure and temperature
- Body
- in-line or angle
- Steam temperature
- up to 650 °C
- Pressure
- up to 270 bar
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
TBV (Turbine Bypass Valve) and PRDS (Pressure Reducing and Desuperheating Station) valves are control valves for the steam-water cycle of power plants. The turbine bypass valve is fast-acting, with a large flow capacity. It diverts steam around the steam turbine in off-design modes: during start-up, shutdown and emergency trip. This protects the turbine and the boiler, and gives the power unit operating flexibility during transients. The PRDS valve reduces steam pressure and temperature at the same time to the values the downstream consumer needs, for example for process steam or the plant's own needs. By purpose it is a functional analogue of ШРОУ and РОУ, used in steam turbine installations of thermal and CHP plants.
Both types are made with an in-line or angle body and are designed for large flows and significant pressure drops. A cooling water injection system is built into the outlet part of the valve. Steam temperature is maintained either by a temperature feedback loop or by enthalpy with direct feedforward. The closure is a metal balanced plunger or a plunger with a pilot, which gives fast stroking and smooth control. Against cavitation and noise, and for a wide control range, multi-stage cages (multicage) or outlet silencers are offered, and the trim is selected for the specific duty.
The body is made of chrome-molybdenum or high-chromium steel, and the body-bonnet joint is self-sealing (pressure seal). Steam temperature is up to 650 °C and pressure up to 270 bar. The valves are intended for conventional thermal power plants, combined-cycle plants with heat recovery steam generators (HRSG), and also geothermal, solar and nuclear stations. In the same line the company makes boiler valves and desuperheaters, so an installation can be supplied as a complete package.
From the supply experience cited by the company: more than 4000 valves for the IGCC Jazan power unit (Saudi Arabia), including the largest valve for cogeneration steam. Desuperheating systems made of Gr.91 steel (steam 150 bar, 575 °C) were rebuilt at three Italian combined-cycle plants. Control valves and PRDS are available for combined-cycle plants in Croatia, and heat recovery boiler valves, PRDS and blowdown valves for stations in Germany, the United Kingdom, Italy and Peru. Valves with a self-sealing bonnet were supplied for superheated steam up to +560 °C.
Technical specifications
| Purpose | TBV: diverting steam around the turbine during start-up, shutdown, emergency trip; PRDS: simultaneous reduction of steam pressure and temperature |
|---|---|
| Body | in-line or angle |
| Steam temperature | up to 650 °C |
| Pressure | up to 270 bar |
| Closure | metal balanced plunger or plunger with pilot (fast stroking) |
| Noise reduction | multi-stage cage (multicage) or outlet silencers |
| Desuperheating | built-in injection in the outlet part; control by temperature (feedback) or by enthalpy (feedforward) |
| Materials | Cr-Mo or high-chromium steel |
| Body-bonnet joint | self-sealing (pressure seal) |
| Application | thermal and CHP plants, combined-cycle plants with heat recovery boilers (HRSG), geothermal, solar and nuclear stations |
Request a price and lead time
TBV / PRDS — steam turbine bypass valves and pressure reducing and desuperheating valves, up to 270 bar, up to 650 °C. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What are the maximum steam parameters of TBV and PRDS valves?
Steam temperature up to 650 °C, pressure up to 270 bar. The body is made of chrome-molybdenum or high-chromium steel, and the body-bonnet joint is self-sealing.
What is the difference between the TBV turbine bypass valve and PRDS?
TBV diverts steam around the steam turbine during start-up, shutdown and emergency trip. PRDS reduces steam pressure and temperature at the same time for the downstream consumer.
Which power plants are these valves suitable for?
For conventional thermal and CHP plants, combined-cycle plants with heat recovery steam generators (HRSG), and also geothermal, solar and nuclear stations. Valves with a self-sealing bonnet were supplied for superheated steam up to +560 °C.
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