Jun. 06, 2020
The external shape of the axial flow pump is cylindrical, and its main components include bell mouth, impeller, guide vane body, outlet elbow, pump shaft, bearing and shaft sealing device.
(1) Bell mouth
The main function is to introduce the water flow into the impeller smoothly with minimum loss. Generally, the cast iron horn tube conforming to the streamline shape is adopted, and its diameter is about 1.5 times the diameter of the impeller. Large-scale axial flow pumps generally do not use bell mouths, but adopt on-site pouring inlet flow channels.
Usually consists of blades, hubs and water guide cones. The blades are generally 4-6 pieces in a twisted shape and are installed on the hub body. The material of the blades is required to be resistant to corrosion and cavitation. Generally, high-quality cast iron is used, and large pumps are mostly made of cast steel.
(3) Guide vane body
The guide vane body is the pressurized water chamber of the axial flow pump, which is installed above the impeller, and is composed of a guide vane, a guide vane hub and a casing. The guide vane generally has 6 to 12 pieces and is fixed on the guide vane hub and the outer shell, and the outer shell is in the shape of an inverted cone. The main function of the guide vane body is to change the rotational movement of the water flow from the impeller into an axial movement, and gradually reduce the flow velocity, thereby converting part of the kinetic energy into pressure energy. The guide vane body is also equipped with a lower guide bearing.
(4) Pump shaft and bearing
The pump shaft is used to transmit torque and is generally made of high-quality carbon steel. The pump shaft of a large fully-regulated axial flow pump is often made into a hollow shaft to facilitate the installation of blades in it. There are two types of bearings for axial flow pumps, one is a guide bearing and the other is a thrust bearing.
(5) Shaft sealing device
The shaft sealing device is installed at the shaft hole where the pump shaft passes through the pump casing to prevent the leakage of pressure water. The commonly used shaft sealing device is a stuffing box. Its structure is similar to the stuffing box of a centrifugal pump, except that there is no water sealing tube and water. Sealing ring, the pressure water in the pump can directly enter the packing for lubrication and cooling.
(6) Outlet elbow
After the water flows out of the guide vane body, it enters the outlet elbow through a section of diffusion pipe. The role of the elbow is to smoothly lead the water out of the pump body. The elbow angle is usually 60°.
The above information is provided by axial flow water pump manufacturer.