The factors affecting the efficiency of the centrifugal pump set are analyzed, and improvement measures are proposed to improve the operating efficiency of the centrifugal industrial pump and reduce the energy consumption of the equipment.
A. Several factors affecting the efficiency of the centrifugal pump set
The efficiency of a centrifugal pump is the product of three efficiencies: mechanical, volume and hydraulic. The efficiency of the pump set is the product of pump efficiency and motor efficiency. The main factors that cause the efficiency of the centrifugal pump set are as follows.
1. The efficiency of the industrial pump itself is the most fundamental impact. For pumps under the same working conditions, the efficiency may differ by more than 15%.
2. The operating condition of the centrifugal pump is lower than the rated working condition of the pump, the pump efficiency is low, and the energy consumption is high.
3. Motor efficiency remains basically unchanged during operation. Therefore, it is important to choose a high-efficiency motor.
4. The impact of mechanical efficiency is primarily related to design and manufacturing quality. After the pump is selected, the post management impact is small.
5. Hydraulic losses include hydraulic friction and local resistance loss. After the pump is running for a certain period of time, the surface of the impeller and the vane and the like are inevitably worn, the hydraulic loss is increased, and the hydraulic efficiency is lowered.
6. The volume loss of the pump is also called leakage loss, including three leakage losses of the impeller seal ring, the interstage, and the axial force balance mechanism. The volumetric efficiency is not only related to design and manufacturing, but also related to post management. After the pump is continuously operated for a certain period of time, the gap is increased due to friction between the components, and the volumetric efficiency is lowered.
7. The centrifugal pump is evacuated and idling due to blockage of the filter cylinder, intake of the pipeline, and the like.
8. Before the pump starts, the staff does not pay attention to the preparation work before the start of the centrifugal pump. The basic operating procedures such as the warm pump, the disc pump and the infusion pump are not performed thoroughly, which often causes the cavitation phenomenon of the pump, causing the pump to have large noise, large vibration and pump efficiency. low.
B. Measures to reduce the energy consumption of centrifugal pumps and improve the efficiency of the pump set
1. Replace 14 inefficient centrifugal pumps. When replacing, the multi-stage centrifugal pump is selected close to the actual operating conditions, ensuring that the replaced pump is always operating in an efficient state. We did the efficiency comparison experiment before and after the centrifugal pump replacement. The experiment shows that after replacing the inefficient and high-consumption centrifugal pump, the pump efficiency can be improved by about 10%.
2. Application of frequency conversion energy-saving technology. For centrifugal pumps with design parameters greater than the actual operating conditions, after installing the variable frequency speed control device, it always runs in the high efficiency zone.
3. Promote the application of new energy-saving products such as high-efficiency and energy-saving permanent magnet speed regulating motors and dual power motors on the main centrifugal pumps.
4. Selection of centrifugal pumps. When selecting a new pump, the pump produced by a large manufacturer should be selected to ensure high efficiency of the centrifugal pump.
5. Maintenance of the centrifugal pump.
(1) Always check and adjust the centrifugal pump shaft end seal to reduce the volume loss;
(2) When the centrifugal pump has been running for 10,000 hours, it should be overhauled to restore the pump efficiency;
(3) Promote the application of bellows sealing technology on the centrifugal pump to completely eliminate the leakage of the centrifugal pump and improve the volumetric efficiency.
6. Regularly clean the filter cylinder, check the pipeline connection, and ensure that the centrifugal pump inlet line is unblocked.
7. Strictly follow the operating rules of the centrifugal pump. Before starting the pump, the disc pump should be opened, the inlet valve should be opened, the outlet valve should be closed, and the exhaust gas should be vented to check whether the inlet pressure of the pump meets the requirements. Prevent cavitation of the pump due to low supply pressure and insufficient flow.
8. Regularly check the pump efficiency of the centrifugal pump. For the pump set with low pump efficiency, it is necessary to find the cause in time and take corresponding measures to solve it. When a centrifugal pump is used to pump a slurry stream containing large, medium, and small materials in a liquid, the liquid is sprayed tangentially into the cylindrical chamber to form a vortex, and a portion of the liquid is tangentially excluded from the chamber. Spraying the slurry axially into the chamber, the vortex separating the large-sized material from the remaining mud and liquid; removing the remaining mud and liquid from the chamber in the axial direction, and spraying it into the inlet of the centrifugal pump; The material coming out of the centrifugal pump acts as a spray liquid for forming the vortex, thereby reducing the wear of the centrifugal pump impeller and increasing the efficiency of the centrifugal pump. A method for reducing the wear of a centrifugal pump impeller and improving the efficiency of a centrifugal pump when the centrifugal pump is used to pump a slurry stream containing a large to small size material in the liquid, characterized in that it comprises: a tangentially injecting liquid into the vortex Forming a vortex and removing a portion of the liquid from the chamber tangentially; b injecting the slurry axially into the chamber, the vortex separating the large size of the material from the remaining mud and liquid remaining; The mud and liquid are removed from the chamber in the axial direction and sprayed into the inlet of a centrifugal pump; d uses the material from the centrifugal pump as the spray liquid forming the vortex; therefore, the large-sized material is moved The outer circumference of the vortex is discharged, and as a result, medium, small, and sized materials and liquid are sprayed into the centrifugal pump, thereby reducing wear of the impeller and allowing the pump to operate at a high speed, thereby improving efficiency.
