Introduction to the structure of sewage pump impeller
The sewage pump is a pump product that is connected with a pump and a motor and works under the liquid at the same time. Compared with a general horizontal pump or a submersible sewage pump, the sewage pump has a compact structure and a small area. Submersible Pump Co., Ltd. cited easy installation and maintenance. Small sewage pumps can be installed freely. Large sewage pumps are generally equipped with automatic coupling devices for automatic installation. Installation and maintenance are quite convenient. Long continuous operation time. Since the sewage pump and the motor are coaxial, the shaft is short, and the rotating parts are light in weight, the load (radial) on the bearing is relatively small, and the service life is much longer than that of the general pump. There are no problems such as cavitation damage and irrigation. Especially the latter point brings great convenience to the operator. Low vibration and noise, low temperature rise of the motor, no pollution to the environment. The following describes the impeller types of sewage pumps:
1. Impeller structure type: The structure of the impeller is divided into four categories: blade type (open type, closed type), swirl type, flow channel type, (including single flow channel and double flow channel) spiral centrifugal type, open type The semi-open impeller is easy to manufacture. When the impeller is blocked, it can be easily cleaned and repaired. However, in the long-term operation, under the abrasion of particles, the gap between the blade and the side wall of the pressurized water chamber will increase, thereby increasing the efficiency reduce. And the increase of the gap can destroy the pressure difference distribution on the blade. Not only produces a large amount of vortex loss, but also increases the axial force of the pump. At the same time, due to the increase of the gap, the stability of the liquid flow in the flow channel is destroyed, causing the pump to vibrate. This type of impeller is not easy to transport For media with large particles and long fibers, in terms of performance, this type of impeller has low efficiency. The highest efficiency is about 92% of that of an ordinary closed impeller, and the head curve is relatively flat.
2. Rotating impeller: The pump adopts this type of impeller, because the impeller is partially or completely retracted from the flow passage of the pressure chamber. Therefore, the non-blocking performance is good, and the passing capacity of particles and long fibers is strong. The particles flow in the water pressure chamber driven by the vortex generated by the rotation of the impeller. The movement of the suspended particles does not generate energy, and the flow channel exchanges energy with the liquid. In the flow process, suspended particles or long fibers do not contact the worn blades, and the blades are more abraded. There is no situation that the gap is enlarged due to abrasion, and it will not cause a serious drop in efficiency during long-term operation. This type of impeller pump is suitable for pumping media containing large particles and long fibers. In terms of performance, the efficiency of the impeller is relatively low, only equivalent to about 70% of the ordinary closed impeller, and the head curve is relatively flat.
3. Spiral centrifugal impeller: The blades of this type of impeller are twisted helical blades that extend axially from the suction port on the conical hub body. This type of impeller pump has the functions of a positive displacement pump and a centrifugal pump. When the suspended particles flow through the blades, they will not hit any part of the pump, so it has good non-destructive performance. The damage to the conveyed material is small. Due to the propelling effect of the screw, the suspended particles can pass through, so the pump adopting this type of impeller is suitable for pumping the medium containing large particles and long fibers, and the medium with high concentration. It has obvious characteristics when there are strict requirements on the damage of the conveying medium.
4. Flow channel impeller: This impeller is a bladeless impeller. The flow channel of the impeller is a curved flow channel from the inlet to the outlet. Therefore, it is suitable for pumping media containing large particles and long fibers. Good blocking resistance. In terms of performance, the efficiency of this type of impeller is not much different from that of an ordinary closed impeller, but the lift curve of the pump with this type of impeller drops steeply. The power curve is relatively stable, and it is not easy to cause overpower problems, but the cavitation performance of this type of impeller is not as good as that of ordinary closed impellers, and it is especially suitable for pumps with pressure inlets.
5. Closed impeller This type of impeller has a normal higher efficiency. In the long-term stable operation, the axial force of the pump using this type of impeller is small, and auxiliary vanes can be set on the front and rear cover plates. The auxiliary vanes on the front cover can reduce the vortex loss at the impeller inlet and the wear of the seal ring by particles. The auxiliary vanes on the back cover not only balance the axial force, but also prevent suspended particles from entering the mechanical seal cavity to protect the mechanical seal. However, this impeller has poor non-blocking properties and is easy to entangle, and is not suitable for pumping untreated sewage media containing a large number of particles (long fibers). In summary, regardless of any series of sewage pump impellers, it is just a combination of different types of impellers and different types of pressurized water chambers according to the requirements of the conveying medium and installation, as long as the impeller and pressurized water chamber can be optimized. The various performances of the pump will be guaranteed.
