Sewage pump is a kind of centrifugal impurities, which has many forms: such as submersible and dry type. At present, the most common submersible type is WQ submersible sewage pump, and the most common dry sewage pump is W type. There are two types of horizontal sewage pump and WL vertical sewage pump. It is mainly used to transport urban sewage, and fiber is contained in feces or liquid. The medium of solid particles such as paper scraps, usually the temperature of the medium being conveyed is not more than 80° C.
Sewage pump China like other pumps, the impeller, the pressure water chamber, are the two core components of the sewage pump. The pros and cons of its performance also represent the pros and cons of the pump performance, the anti-clogging performance of the sewage pump, the level of efficiency, and the cavitation performance, and the anti-abrasion performance is mainly guaranteed by the two components of the leaf pump and the pressure water chamber. The following are introduced separately:
1. Impeller structure:
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 semi-open impellers are easy to manufacture. When the impellers are clogged, they can be easily cleaned and repaired. However, in the long-term operation, the clearance between the blades and the side wall of the pressurized water chamber will increase under the abrasion of particles, so that Reduced efficiency. And the increase of the gap destroys the pressure difference distribution on the blade. Not only a large amount of vortex loss, but also the axial force of the pump is increased. At the same time, due to the increased gap, the stability of the liquid flow in the flow channel is damaged, causing the pump to vibrate. This type of impeller is not easy to convey Large particles and long-fiber media, from the performance point of view, this type of impeller has low efficiency, the highest efficiency is about 92% of the ordinary closed impeller, the head curve is relatively flat.
2. Swirl impeller:
With this type of impeller pump, the impeller is partially or completely retracted from the flow channel of the pressure water chamber. Therefore, the non-clogging performance is good, the particle passing ability and the long fiber passing ability are strong. The particles move in the pressurized water chamber under the impetus of the vortex generated by the impeller rotation. The suspended particles themselves do not generate energy, but only exchange energy with the liquid in the flow channel. During the flow process, suspended particles or long fibers do not come into contact with the blades, and the blades are more abraded, and there is no increase in the gap due to abrasion. It will not cause a serious decline in efficiency in long-term operation. The type of impeller pump is suitable for pumping media containing large particles and long fibers.
In terms of performance, the impeller has a low efficiency, which is only about 70% of that of an ordinary closed impeller, and the head curve is relatively flat.
3. Closed impeller:
This type of impeller has higher normal efficiency. And the situation is relatively stable in long-term operation, the axial force of the pump using this type of impeller is small, and auxiliary blades can be provided on the front and rear cover plates. The auxiliary blade on the front cover can reduce the vortex loss at the inlet of the impeller and the wear of the seal ring by the particles. The auxiliary blade on the rear cover not only plays a role of balancing the axial force, but also can prevent suspended particles from entering the mechanical seal cavity to protect the mechanical seal. However, this type of impeller has poor blocking resistance and is easy to be wound. It is not suitable for pumping untreated sewage media containing large particles (long fibers).
4, runner impeller:
This type of impeller is a bladeless impeller. The impeller flow channel is a curved flow channel from the inlet to the outlet. It is suitable for pumping media containing large particles and long fibers. Good blocking resistance.
The sewage pump supplier believes that this type of impeller has high efficiency and is not much different from the ordinary closed impeller, but the lift curve of this type of impeller pump is relatively steep. The power curve is relatively stable, and it is not easy to cause the problem of overpower, 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 inlet.
5. Spiral centrifugal impeller:
The blades of this type of impeller are twisted spiral blades, which extend axially from the suction port on the conical hub body. This type of impeller pump has the function of both a positive displacement pump and a centrifugal pump. When suspended particles flow through the blade, it does not hit any part of the pump, so it is non-destructive. Less destructive to conveyed objects. Due to the propelling effect of the spiral, the penetrability of the suspended particles is strong, so the pump using this type of impeller is suitable for pumping media containing large particles and long fibers, and high-concentration media. It has obvious characteristics in the occasions with strict requirements on the damage of the conveying medium.
In terms of performance, the pump has a steeply decreasing head curve, and the power curve is relatively flat.
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