Simply look at the power flow is actually water, steam cycle process, in this selection process control valves both simple and complex. Media is simple and easy process, only the water and steam are two kinds of complex water and steam temperature and pressure fluctuations over large areas, has brought a series of issues such as: flash, cavitation, erosion, noise, corrosion. But the first thing to consider is the control valve of the safety and reliability.
To the valve (main, with a boiler valve, compound feed water control valve)
Control requirements: Control of the boiler into the water to ensure steam evaporation, and the maintenance of the boiler water level (main, with a boiler to the valve system consists of two control valves, one for the boiler starts to use, one for normal water use).
Condition: The boiler starts up to 100-300 kg of pressure valves, flow smaller, less pressure during normal operation, traffic flow, flow rate adjustable ratio 75/1-100/1.
Valve requirements: WCB/WC9, for the pairs of valves in the system requirements to start anti-cavitation valve, V-class off class for the compound to the water valve need to use features of Valve parts while meeting the boiler startup and normal operation needs. Generally choose to fail off valve.
Boiler feed pump minimum flow valve cycle
Control requirements: the safety of boiler feed pump to start and stop running, to eliminate traffic is too small, temperature increase, the water a strong cavitation damage to the pump. (Old-fashioned power stations are used to switch-based minimum flow control valves, along with the use of mechanical pumps automatically cycle valves).
Condition: The pressure drop of up to 160-350 kilograms, is the largest power plant systems to withstand pressure valves, flow for a regular flow of 30%.
Valve requirements: anti-cavitation and plug up the structure, V-class seal level, pump start and stop running when the valve continuous work, pump normally starts the valve closed, the valve usually fail to open.
Low heater trap (hydrophobic water heaters, condensing water heater hydrophobic)
Control requirements: Control of condensation water heater location, promptly condensate water discharge, high water discharge, the normal water level of hydrophobic
Condition: The saturated water heater control valve between the pressure is usually 6-30 kg, finally a trap directly connected to the condenser or deaerator.
Valve requirements: anti-flash erosion, V, or VI level seal rating, the valve usually fail to open.
Deaerator Water Level Control Valve (DALC)
Control requirements: to provide flow deaerator to maintain a normal water level, by adding steam to increase temperature to eliminate the gas dissolved in the water.
Condition: The flow of small start-up phase, pressure of high temperature, the normal flow of large pressure difference is small, similar to the valve condition.
Valve requirements: low-flow and effective anti-cavitation.
Temperature reduction valve (desuperheater)
Control requirements: the high-pressure water jet of steam into the steam temperature manipulation to control requirements, working conditions: The water pressure higher.
Valve requirements: type of diversity: nozzle type, assisted atomization type, self-contained type and right-clip.
Reduced temperature valves (high and low pressure bypass valve)
Control requirements: the high-temperature high-pressure steam to adjust to a certain temperature and pressure of steam to the steam turbine to provide a bypass channel, boilers, steam turbine capable of independent working.
Condition: The high temperature and pressure steam.
Valve requirements: resistance to thermal shock, noise reduction, quick response.
ball valve Trunnion Mounted Ball Valve Floating Ball Valve Top Entry Ball Valve Three way ball valve V Type Ball Valve
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