Products Details

Empty discharge check valve, also known as automatic return valve, is a special purpose check valve, mainly used in the outlet of the boiler feed pump, its role is to prevent the backflow of the medium and play an empty discharge role. This valve is usually installed on the high pressure feed pump outlet pipe of the thermal power unit to protect the feed pump and prevent water backflow. When the feed pump is under low load or the outlet stop door is closed, the empty discharge check valve works with the automatic recirculation bypass valve to ensure the safe operation of the pump. When the air discharge check valve is opened, the recirculation bypass valve automatically closes, and vice versa.

The design features of the air discharge check valve include the linkage between the opening and closing of the main valve disc and the bypass opening, which can automatically control the bypass flow and achieve the purpose of energy saving and emission reduction. They are usually fully automatic and require no external drive, reducing energy consumption and additional equipment investment, and reducing installation and maintenance costs. In addition, it can ensure the stable operation of the main pump even at low flow rates, reduce the occurrence of water hammer in the system, and protect the safety of the equipment.

In terms of material selection, the valve body and connection flange of the empty discharge check valve are usually made of carbon cast steel, while the guide shaft, fork and other parts are made of stainless steel to ensure wear resistance and abrasion resistance and reliable sealing. The nominal pressure range of the valve is PN160 to PN320, the nominal size is from DN50 to DN300, the valve body material can be 20 steel, A105 or WCB, suitable for steam, water and other media, the operating temperature range from -29℃ to 570℃.

It is worth noting that the empty discharge check valve should not be used for media containing solid particles and large viscosity. According to the specific engineering needs and application conditions, the specifications and parameters of the valve may be different, but it is usually produced in accordance with certain design and manufacturing standards, such as NB/T 47044, and tested in accordance with the corresponding inspection and test standards.