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Application of spiral centrifugal pump in sludge treatment
- Dec 11, 2018 -

       1, One of the most critical parts of the spiral centrifugal pump is its unique spiral centrifugal impeller, which has both a spiral section and a centrifugal section. It combines the advantages of the high efficiency of the conventional centrifugal pump and the non-clogging of the screw pump, so it is called a spiral centrifugal pump.

       2, the origin of the spiral centrifugal pump

      The spiral centrifugal pump originated in Switzerland and was originally designed to help Peruvian fishing plants transport live fish from fishing vessels. The pump can transport live fish from the fishing net to the ship and then on board by relying on the non-blocking and gentle conveying characteristics of the spiral centrifugal impeller. Transfer to the processing plant. With the development and improvement of products, the application field of spiral centrifugal pumps is gradually expanding.

      3. The application fields of spiral centrifugal pumps are widely used in municipal sewage, sludge, petrochemical, pulp wastewater, food processing and other fields.

      4, the characteristics of the spiral centrifugal pump

      Compared with general ordinary impurity pumps and swirl pumps, the structure of the spiral centrifugal pump determines its characteristics:

   A. Good non-clogging performance: The large passage formed by the blade, together with the inlet guide and the screw propulsion, can transport liquids containing large particles and fibrous substances, especially long-fiber objects can pass smoothly. The solids delivered are higher in concentration than other types of non-blocking pumps, and the diameter can be much improved compared to conventional centrifugal impellers of similar outer diameter. B. Soft conveying, good non-destructive performance: the solid-liquid two-phase fluid gradually advances under the action of the balanced spiral force, and the flow direction has no sudden change, so the flow balance. It is especially suitable for transporting activated sludge during sludge treatment and can maintain the characteristics of activated sludge. C, high efficiency and high efficiency zone width D, power curve is flat. E. Characteristic curve with steep drop: When the head changes, the flow change is small, which can ensure continuous and stable operation. F. The pump has good suction performance: the pump blade extends forward to the suction port, so the gas-containing medium can be pumped. When the trace gas is inhaled, the performance, vibration and noise of the pump do not change substantially. When the gas content exceeds 40%, the pump Although it will produce intermittent vibration, it will still work. G, high solid content.

      5. Application of spiral centrifugal pump in sewage treatment

In our large number of surveys, the most prominent problem reflected by the sewage pump is the frequent blockage. One reason is that many construction wastes were not cleaned up in time before the pump house was used. Many loose small stones, small steel bars and scaffold pipe clamps were still left at the bottom of the pump house after the construction was completed. Another reason is that the sewage itself contains various kinds of garbage. Although there are grille intercepts, the coarse grid pitch is generally 20-30mm. Miscellaneous objects, especially fibrous matter, will still become more entangled in the pump by intercepting the snowball until the impeller is blocked, and the equipment stops running.

   The conventional centrifugal pump, when the water flows into the volute and is thrown out by the centrifugal action, the sudden change in the direction of the 90-degree angle will inevitably cause a significant collision. The sudden change in this direction makes it easy for the solid to stay in the volute due to inertia. Or on the impeller, causing blockage and greatly reducing the pumping capacity of conventional centrifugal pumps.

At the same time, conventional centrifugal pumps are even more powerless when transporting fiber solids. The diameter of the spherical particles passing through the solid claimed by the conventional non-blocking pump is only for the more regular solid particles and does not reflect the ability to transport the fibrous object. But in fact, when passing a large number of fibrous objects (such as hair, ladies stockings, sanitary napkins, etc.), these fibers are hooked by the impeller after entering the pump body, and are wound around the impeller until the pump stops.

      The advantage of the non-clogging of the spiral centrifugal pump is that the impeller has a twisted spiral blade which is extended axially by the suction port, and the radius of the blade is gradually increased to form a very wide spiral flow path. The casing is composed of a suction port, a lining and a volute. The impeller of the suction port part produces a spiral propulsion, and the impeller of the volute part generates centrifugal action. The acute angle part of the blade inlet guides the debris to the shaft attachment, and then uses the spiral action. After propelling along the axis, the solid particles enter the impeller after the solid particles enter the impeller, and enter the pump body by the parabolic surface formed by the rotation of the spiral vane. Although the rotation is also 90 degrees, the trajectory of the particles passing through the spiral centrifugal pump is gradual, so the liquid The flow is in a smooth open channel and is pumped through under low stress, low mixed flow conditions. And this unique design also allows non-blocking passage of liquids with high solids.

      For fine fibers such as soft, easy-to-twist hair, the impeller inlet lining is designed with a unique protrusion that effectively leaves the fibers behind the guard ring, which prevents the impeller tip from hooking the fibers. The blockage also prevents damage to the tip of the impeller caused by the filament wound impeller, which solves the problem of fiber blockage of the conventional non-blocking pump.

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