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Installation points of imported empty row check valve

The purpose of the check valve is to only allow the pump to deliver water out of the water without allowing the water to flow back to the pump. When the pump stops suddenly, the high pressure water flows back to the pump and the pump reverses.
Installation points of empty row check valve
The empty row check valve is installed on the high pressure of the thermal power unit to the large pump outlet pipe to prevent backflow of the feed water and protect the feed water pump. The valve works in conjunction with the minimum flow automatic recirculation bypass valve of the pump. When the feed pump is under low load or the outlet is closed, the automatic recirculation bypass valve (automatic recirculation valve) should be in the open position to ensure the safe operation of the pump. . When the empty check valve is opened, the recirculation bypass valve automatically closes. Not suitable for media containing solid particles and high viscosity. The valve works in conjunction with the recirculation bypass valve to maintain safe operation of the system.
Empty row check valve structure features:
b. The main valve flap moves up and down. When the medium is reversed, the channel is closed by the medium pressure and the spring. At this time, the bypass valve is opened. When the main valve flap is fully open, the bypass valve is closed.
c. The valve disc seal is made of stainless steel surfacing, which is wear-resistant, scratch-resistant and reliable.
d. The valve should be installed vertically.
The automatic recirculation valve, also known as the pump protection valve or the minimum flow valve, is used for automatic recirculation of the minimum flow of the centrifugal pump to prevent damage of the centrifugal pump due to overheating, noise and vibration under low load.
The automatic recirculation valve is a self-operated control valve that does not require external energy supply. Compared with the traditional control valve system, it has the following significant advantages:
In the early product procurement, installation and commissioning, as well as the later maintenance, it has a significant cost advantage, the overall cost is 2/3 lower than the traditional control valve system.
Bypass flow can be adjusted and controlled, the overall operation of the valve is highly economical
Fully mechanical structure, relying on flow control valves, no additional energy required
Pump protection is only required for one valve and no additional components are required. Therefore, it is not affected by system failure.
The check valve and bypass in the mainstream road become a whole
Almost maintenance free
Related brands are: Schroedahl domestic brand and Beijing Institute of Aeronautics and Astronautics Shanghai Rambo control valve Zhejiang Huada
Size range: DN25 ~ DN300 Maximum pressure: 4500LB
working principle:
Automatic recirculation valves are needed. For centrifugal pumps, a bypass is required to prevent overload and superheated vaporization from causing damage to the pump at operating below the specified minimum flow rate. In thermal power plants, the amount of water that is supplied to the feed pump varies with the boiler load. At the start-up or when the load is very low, the feed pump is likely to operate with a small amount of water supply or zero water supply. The water is heated by the friction of the impeller in the pump body for a long time, and the water temperature rises and the water temperature rises. When it reaches a certain level, it will vaporize and form cavitation. Cause damage to the feed pump.
In order to prevent this from happening, a recirculation system is installed between the feed water pump outlet and the deaerator (or condenser) water tank, and the recirculation system can be opened when the feed water pump is just started or when the water supply amount is small to a certain extent. Return a portion of the water to the deaerator tank to ensure that a certain amount of water (typically about 30% of the rated flow) passes through the pump without vaporizing the water temperature in the pump. When the water supply is under normal conditions, the recirculation system is turned off.
The previous control method consisted of a complex control system that consisted of a pump protection and control system. The recirculation system consists of a minimum flow valve, a check valve, and a flow measurement system. The flow measurement system in the system determines when to open or close the recirculation system;
The purpose of the check valve is to only allow the pump to deliver water out of the water without allowing the water to flow back to the pump. When the pump stops suddenly, the high pressure water flows back to the water pump to cause the pump to reverse; the minimum flow valve ensures that the high pressure water is depressurized to make the valve outlet pressure and the deaerator (or condenser) tank pressure when the recirculation system is in the open state. Proximity does not cause the deaerator (or condenser) tank to oscillate and cavitation. Clearly, the most important of the recirculating systems, the worst working conditions, are undoubtedly the smallest flow valves.
Features:
l Reduce the investment cost of equipment
l No need for thermal flash evaporation
l No additional power and control signals
l Designed to simplify installation
l Save energy
l Compact and automatic operation, no actuator required
l Simple maintenance
l fail-safe open bypass
l The same applies to the variable speed pump system

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