Automatic recirculation valve also known as pump protection valve or minimum flow valve
Release Time:
2022-09-05
Automatic recirculation valve, also known as pump protection valve or minimum flow valve, is used for automatic recirculation of the minimum flow rate of the centrifugal pump to prevent damage to 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 terms of early product purchase, installation and commissioning, and later maintenance, it has a significant cost advantage, and the overall cost is 2/3 lower than that of traditional control valve systems
Bypass flow can be adjusted and controlled, and the overall operation of the valve is highly economical
Completely mechanical construction, relying on flow control valves, requires no additional energy
Only one valve is needed to realize the protection of the pump, and no other additional components are required. Therefore, it is not affected by system failure.
The check valve in the main channel and the bypass are integrated
almost maintenance-free
Related brands include: Schroedahl, domestic brands, Beijing Aviation Research Institute, Shanghai Rambo Control Valve, Zhejiang Huada
Size range: DN25～DN300 Maximum pressure: 4500LB
working principle:
Automatic recirculation valves come where you need them. For centrifugal pumps, a bypass is required to prevent damage to the pump due to overload and superheated vaporization caused by operation below the specified minimum flow rate. In thermal power plants, the water output of the feed water pump varies with the boiler load. When starting or when the load is very low, the feed water pump is likely to run with a small or zero water supply. The water in the pump body is heated by the friction of the impeller for a long time, which causes the water temperature to rise. After reaching a certain level, vaporization will occur, forming cavitation. cause damage to the water pump.
In order to prevent the occurrence of the above phenomenon, a recirculation system is installed between the outlet of the feed water pump and the water tank of the deaerator (or condenser), and the recirculation system can be turned on when the feed water pump is just started or when the water supply is small to a certain extent. Return part of the water to the deaerator water tank to ensure that a certain amount of water (generally about 30% of the rated flow) passes through the pump without causing the water temperature in the pump to rise and vaporize. And when the water supply is under normal conditions, close the recirculation system.
In the past, the control method was composed of a complex control system to form a pump protection and control system. The recirculation system consists of a minimum flow valve, a check valve, and a flow measurement system. A flow measurement system in the system determines when to turn on or off the recirculation system;
The purpose of the check valve is to only allow the pump to send water out, but not to allow the water to flow back into the pump. Prevent the high pressure water from flowing back to the pump when the pump suddenly stops running, causing the pump to reverse; the minimum flow valve ensures that when the recirculation system is in the open state, the high pressure water is decompressed so that the outlet pressure of the valve is equal to the pressure of the deaerator (or condenser) water tank Close to the water tank without causing the deaerator (or condenser) pressure shock and cavitation. Obviously, the most important and the worst working condition in the recirculation system is undoubtedly the minimum flow valve.
Features:
l Reduce the investment cost of equipment
l No thermal flash generation
l No need for additional power supply and control signal
l Simplified design and easy installation
l Save energy
l Compact structure and automatic operation, no need for actuators
l Simple maintenance
l Failsafe open bypass
l It is also applicable to the speed regulating pump system
Tel
ADD
No. 115, Shuangxi Road, Qingyang Economic and Technological Development Zone, Chizhou City, Anhui Province, China
We are committed to:
High, medium and low pressure ball valves, gate valves, globe valves, butterfly valves, steam traps, regulating valves, pressure reducing valves, hydraulic control valves, throttle valves, power station valves, emergency shut-off valves, and other products.
We are committed to:
High, medium and low pressure ball valves, gate valves, globe valves, butterfly valves, steam traps, regulating valves, pressure reducing valves, hydraulic control valves, throttle valves, power station valves, emergency shut-off valves, and other products.
Maintenance and transportation
Service Hotline：
13485660555
SAF Coolest v1.3 设置面板 ATISX-ZYPN-QDADE-AWA
无数据提示
Sorry，当前栏目暂无内容！
您可以查看其他栏目或返回 首页