[Hongjie Water Service] Selection of feed pump form for sludge dewatering machine

The flow rate of a single feed pump should not only be calculated based on sludge volume, dewatering time, and number of units, but also consider matching with the processing capacity and cycle of the dewatering machine, and communicate with the dewatering machine supplier for confirmation.

The head calculation of the feed pump not only needs to consider the requirements of the sludge dewatering machine, but also needs to consider the resistance along the way. The calculation of the resistance along the pipeline needs to consider the density requirements of the overflow sludge.

The feed pump of the sludge dewatering machine is selected based on the characteristics of the wastewater, the parameters of the feed pump, and the requirements of the sludge dewatering machine, mainly including:

① Centrifugal pump. The shear force on sludge is high, which can damage the sludge flocs and result in poor wear resistance.

② Diaphragm pump. Commonly used in corrosive media and dosing systems, it has a shearing effect on the medium.

③ Plunger pump. Expensive and often used in situations with high pressure requirements, it can be used as a feed pump for plate and box filter presses.

④ Screw pumps can transport high viscosity substances (different from gear pumps) or media containing gas, particles, or fiber impurities (different from diaphragm pumps), as well as acid, alkali, and salt media.

The flow rate of the screw pump should consider the processing capacity of the dewatering machine, and be designed according to the maximum flow rate with a certain margin, because sludge particles will wear the rotor and stator, causing a decrease in flow rate. When the flow rate drops to 85% of the design value, the stator needs to be replaced.

However, the design flow rate should not be too large, as throttling can cause significant losses, leading to temperature rise and pump damage. It is not possible to rely on the pressure regulating valve for high flow backflow to meet the requirements of low flow.

⑤ Cam rotor pump (i.e. rotor pump), similar to screw pump design points, but for sludge with high sediment content, the speed cannot be high.

The rotary pump has no blockage problem, low energy consumption, small size, and occupies a small area. It can allow for short dry operation and prevent pump damage in the event of sudden material interruption or operational errors. It can achieve online maintenance without dismantling the pipeline, and has low spare parts costs.

The self suction capacity of a rotary pump is lower than that of a screw pump, so its self suction performance should not be considered.

Centrifugal pumps and diaphragm pumps are usually not used in the transportation of concentrated sludge. Single screw pumps (i.e. screw pumps) and rotor pumps are commonly used as feed pumps for belt filter presses and centrifugal dewatering machines. High performance screw pumps can also be used as feed pumps for diaphragm plate and frame filter presses.

Both screw pumps and rotary pumps are suitable for transporting sludge, with uniform and continuous flow, no turbulence and shear, and small pulsation, which is conducive to maintaining the characteristics of sludge and protecting flocs from damage, thus achieving better dewatering effects.

Rotary pumps are more expensive than screw pumps and are more suitable for conveying food grade media.

The feed pump is mainly selected based on flow rate and pressure. When the flow rate is greater than 70m3/h, due to energy consumption reasons, it is advisable to choose a rotor pump, but the investment will be relatively high.

When the flow rate is less than 40m3/h, it is advisable to choose a screw pump.

Economic energy consumption comparison is required to determine the intermediate flow rate. Compared to rotary pumps, screw pumps can achieve higher pressure.

The above is the introduction of "sludge dewatering machine feed pump form selection" by Hongjie Water, hoping to be helpful to you. Before purchasing equipment, we need to have a certain understanding of its composition, then understand its characteristics and defects, and make a comprehensive selection.