Operation Manual for High-Pressure Heater Three-Way Valve The high-pressure heater combined valve is an automatic protection device equipped on high-pressure heaters to ensure that in case of abnormalities such as leakage in the high-pressure heater piping system or jamming of the drain adjustment valve, this valve automatically closes off the water supply to the high-pressure heater piping system and opens the bypass for water supply. Since the high-pressure heater needs to cut off the water supply, a set of water-side protection valves is designed. The term "high-pressure heater combined valve" refers to a set of valves, hence the name "combined valve", which includes inlet and outlet combined valves. The inlet combined valve of the high-pressure heater is commonly referred to as the water supply three-way valve. Three-way valves are divided into electric and hydraulic types, and are most commonly used in units with a capacity of over 300,000. This is because the outlet valves on the water side of the high-pressure heater are mostly designed as electric gate valves. The high-pressure heater combined valves are all hydraulic valves powered by the water supply. When needed, the combined valve is closed to cut off the water supply, and water flows through the small bypass to the outlet combined valve. The outlet valve closes under the action of water from the small bypass, while the water flows through the check valve to the boiler, preventing water cut-off in the boiler and protecting the high-pressure heater. The design of this valve is unique, with an upper valve seat and a lower valve seat. When the valve is opened and water enters the high-pressure heater, the valve core comes into contact with the upper valve seat for sealing, ensuring that the water does not flow through the small bypass. When the valve is closed and water flows through the small bypass into the boiler, the valve core comes into contact with the lower valve seat for sealing, allowing the high-pressure heater to be disconnected and maintained.
The high-pressure heater protection valve is used in the feedwater protection system of high-pressure heaters. When the high-pressure heater fails or is tripped due to other reasons, the valve quickly cuts off the feedwater to the high-pressure heater, causing it to disengage. The feedwater then enters the boiler through a bypass, thus protecting the high-pressure heater and ensuring the normal operation of the unit.
The electric three-way high-pressure heater combined protection valve (inlet valve) or high-pressure heater combined valve features good medium flow lines, low flow resistance, and reliable performance. This valve is a three-way valve, with water inlet on one side, a downward outlet leading to the high-pressure heater, and another outlet connected to the bypass pipeline. The valve has two sealing surfaces, both above and below. During normal operation of the high-pressure heater, the valve is open, with the valve disc moving up to contact the upper seal and the bypass closed. When the high-pressure heater fails or needs to be bypassed for other reasons, the valve disc moves down to close the valve, allowing water to bypass the high-pressure heater and directly enter the boiler through the other outlet, thus disconnecting the high-pressure heater. This valve has two valve seats, with the lower seat replaceable and the upper seat sealed to the valve body with a sealing ring to ensure no leakage during normal operation and long-term service. The sealing surfaces are overlay welded with Stellite alloy, which is wear-resistant, scratch-resistant, and has a long service life. The valve stem adopts a special design process to ensure a switching time of 30 seconds. This valve is paired with an outlet valve (electric gate valve) to ensure the safe operation of the high-pressure heater.