The efficiency of a centrifugal pump is the product of mechanical, volumetric and hydraulic efficiencies. The efficiency of the pump set is the product of the pump efficiency and the motor efficiency. The main factors that cause the low efficiency of centrifugal pump sets are as follows.
The efficiency of the pump itself is the most fundamental impact. Pumps under the same working conditions may differ by more than 15% in efficiency.
The operating conditions of the centrifugal pump are lower than the rated operating conditions of the pump, the pump efficiency is low, and the energy consumption is high.
The motor efficiency remains basically the same in use. Therefore, it is very important to choose a high-efficiency motor.
The impact of mechanical efficiency is mainly related to design and manufacturing quality. After the pump is selected, the later management has less impact.
Hydraulic losses include hydraulic friction and local resistance losses. After the pump runs for a certain period of time, the surface of the impeller and guide vanes will inevitably be worn, the hydraulic loss will increase, and the hydraulic efficiency will decrease.
The volume loss of the pump, also known as the leakage loss, includes three leakage losses of the impeller seal ring, the interstage and the axial force balance mechanism. The level of volumetric efficiency is not only related to design and manufacturing, but also to post-management. After the pump runs continuously for a certain period of time, due to the friction between the various components, the clearance increases and the volumetric efficiency decreases.
The centrifugal pump is evacuated and idling due to the blockage of the filter cylinder and the intake of the pipeline.
Before the pump is started, the employees do not pay attention to the preparatory work before the centrifugal pump is started, and the basic operating procedures such as the heating pump, the disc pump, and the perfusion pump are not fully implemented, which often causes the cavitation of the pump, causing the pump to be noisy, vibration, and pump efficiency.
Measures to be taken to reduce the energy consumption of centrifugal pumps and improve the efficiency of pump sets
Replacement of 14 inefficient centrifugal pumps. When replacing, a centrifugal pump with parameters close to the actual operating conditions is selected to ensure that the replaced pump always runs in a high-efficiency state. We have done a comparison experiment of the efficiency before and after the replacement of the centrifugal pump. The experiment shows that after replacing the low-efficiency and high-consumption centrifugal pump, the pump efficiency can be improved by about 10%.
Application of frequency conversion energy saving technology. For centrifugal pumps whose design parameters are greater than the actual operating conditions, they will always run in the high-efficiency area after installing the frequency conversion speed control device.
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 major centrifugal pumps.
Choice of centrifugal pumps. When choosing a new pump, the pump produced by a large manufacturer should be selected to ensure the high efficiency of the centrifugal pump.
Maintenance of centrifugal pumps.
(1) Check and adjust the shaft end seal of the centrifugal pump frequently to reduce the volume loss;
(2) When the centrifugal pump has been running for 10,000 hours in total, it should be overhauled to restore the pump efficiency;
(3) Promote the application of bellows sealing technology on centrifugal pumps to completely eliminate external leakage of centrifugal pumps and improve volumetric efficiency.
Regularly clean the filter cylinder, check the pipeline connection, and ensure that the centrifugal pump inlet pipeline is unobstructed.
Strictly follow the operating procedures of the centrifugal pump. Before starting the pump, it is necessary to perform the disk pump, open the inlet valve, close the outlet valve, exhaust and vent, and check whether the inlet pressure of the pump meets the requirements. Prevent cavitation of the pump caused by low hydraulic pressure and insufficient flow.
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 the centrifugal pump is used to pump the mud flow containing the materials of large, medium and small size in the liquid, the liquid is sprayed into the cylindrical chamber along the tangential direction, so as to form a vortex, and part of the liquid is discharged from the chamber along the tangential direction. ; The mud is axially sprayed into the chamber, and the vortex separates large-sized materials from the rest of the mud and liquid; the rest of the mud and liquid are axially removed from the chamber and sprayed into the inlet of the centrifugal pump; use The material coming out of the centrifugal pump is used as the jet liquid to form the vortex, thereby reducing the wear of the impeller of the centrifugal pump and improving the efficiency of the centrifugal pump. When the centrifugal pump is used to pump the mud flow containing large to small size materials in the liquid, reduce the The wear of a centrifugal pump impeller and the method for improving the efficiency of a centrifugal pump, characterized in that it comprises:
The operation of the centrifugal pump is mainly to pay attention to filling the pump, check the oil level of the oil cup, the cooling water of the machine seal, the disk shaft, the anchor bolt, and adjust the opening of the outlet valve according to the pump outlet pressure and motor current after the centrifugal pump is started, so as to ensure the centrifugal pump. normal operation.
The liquid is sprayed tangentially into the vortex chamber to form a vortex, and a portion of the liquid is tangentially removed from the chamber;
injecting the mud axially into the chamber, the vortex separates the bulk of the material from the rest of the mud and liquid remaining;
axially drain the remaining mud and liquid from the chamber and spray it into the inlet of a centrifugal pump;
Utilize the material from the centrifugal pump as the spray liquid for forming the vortex;
Therefore, the large-sized material moves toward the outer circumference of the vortex to be discharged, as a result, medium, small, and sized materials and liquids are injected into the centrifugal pump, thus reducing the wear of the impeller and allowing the pump to high speed operation, so the efficiency is improved.
What is the main effect of the opening and closing of the centrifugal pump outlet? Open or small will cause evacuation of the pump (centrifugal pump)? Does the centrifugal pump (the medium is gasoline) need to add cooling water?
The influence of the opening of the centrifugal pump outlet: the positive pressure at the pump outlet of the centrifugal pump is normal (generally 5-8KG), the larger the pump outlet is, the larger the pump flow and the greater the current. The actual pump current is proportional to the pump flow.
The influence of the small opening of the centrifugal pump: the smaller the pump outlet is, the smaller the flow and the smaller the current. Similarly, the actual current of the pump is proportional to the pump flow. The pump outlet is too small to a certain extent, the flow rate of the pump body is too small, the material in the pump cannot be cooled normally to take away the heat of the pump body, and the coil of the pump body is burned out.
The pump outlet is too large, causing the centrifugal pump to be evacuated. reason:
1. The filter before the pump is blocked
2. The inlet pipe diameter of the pump is too small and does not match the pump
3. Material density is too large
The fourth question is not very clear
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