Control requirements: control the position of condensed water in the heater and discharge the condensed water in time, that is, high water level discharge and normal water level discharge.
Working condition: the medium is saturated water, the pressure difference of control valve between heaters is generally 6-30 kg, and the last trap is directly connected to condenser or deaerator.
Valve requirements: flash corrosion resistance, V or VI sealing grade, and valves are usually faulty.
Control requirements: provide flow to maintain normal water level of deaerator, increase water temperature by adding steam, and eliminate dissolved gas in water.
Working conditions: small flow rate and large pressure difference during start-up. Under normal circumstances, the flow rate is large and the pressure difference is small, and the working condition is similar to that of the water supply valve.
Valve requirements: effective cavitation resistance at low flow rate.
Extended data:
When the automobile control valve is working, the inner surface of the thread used to fix the valve seat is easy to corrode due to the infiltration of medium, which makes the valve seat loose, so attention should be paid to it during inspection. For valves working under high pressure difference, check whether the sealing surface of the valve seat is damaged.
The valve core is a moving part in the adjustment work, which is most seriously eroded and corroded by the medium. Check carefully whether all parts of the valve core are corroded and worn during maintenance, especially in the case of large pressure difference (due to cavitation). When the valve core is seriously damaged, it should be replaced. In addition, pay attention to whether there is a similar phenomenon in the valve stem or whether the connection with the valve core is loose.
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