Measures to improve the operating efficiency of centrifugal pumps

Through the centrifugal pump internal loss analysis, comparison of different adjustment methods, as well as centrifugal pump installation, commissioning, maintenance and operation of the use of centrifugal pumps to achieve economic operation, to achieve energy-saving purposes. 1 status quo At present, how to save energy and reduce energy consumption for high-energy-consuming enterprises is imperative for the development of enterprises. The function of the water supply workshop is to provide water for the residents in the living area and the front production plant. The pump running in the workshop must be continuously operated throughout the year. If the centrifugal pump energy-saving measures are not in place, it will inevitably cause high energy consumption while the production of 10 centrifugal pumps in the workshop is relatively early Is sh model, in today's increasingly tense energy situation, how to correctly pump selection, timely adjustment of the pump operating point, the pump running in a higher efficiency zone, conscientiously do the pump maintenance, improve the quality of equipment overhaul and improve the frequency Pump water supply efficiency, pump optimization for saving power consumption, reduce costs, improve the economic efficiency of enterprises of great economic significance. Most enterprises nowadays adopt the most adjustment method by adjusting the inlet and outlet valves to meet the water demand, which is a high energy consumption practice. At present, there are 3 high-pressure frequency conversion units and 1 low-voltage frequency conversion unit in the operation unit of the water supply workshop. How to improve the operation state of the water pump more efficiently, and save energy and reduce consumption, is analyzed from the following aspects. 2 to improve pump operating efficiency 2.1 Causes of low efficiency centrifugal pump reasons: 2.1.1 Centrifugal pump operating conditions deviate from the design point, resulting in the low efficiency of the centrifugal pump. To improve the operating efficiency of centrifugal pumps must reduce the pump loss. Under the same water supply, the higher the efficiency of the motor and pump, the smaller the input power of the motor, the smaller the power consumption. 2.1.2 pipeline inefficient. When the liquid is being transported or flow changes, the adjustment method is often seen through the valve opening adjustment, although this can ensure the operation of the device, but it has caused the pipeline resistance, excessive energy consumption, resulting in centrifugal Low efficiency pump. Most companies are using a constant speed pump to adjust the pump outlet valve opening adjustment to achieve water control. 2.1.3 Some of the centrifugal pump model of choice itself is relatively inefficient, did not consider to clear their own needs of the maximum flow and lift, and in many cases due to improper installation, resulting in centrifugal pump loss is too large, making the centrifugal pump did not play Some effect, run at low efficiency. 2.2 to improve centrifugal pump operating efficiency measures 2.2.1 improve the mechanical efficiency of the pump     2.2.1.1 Reduce Bearing Friction Loss: If the same kind of bearing has different installation quality and different operation and maintenance, its power loss is also different. The workshop adds and lubricates the centrifugal pump on time and according to the "Lubricating Oil Management Specification" formulated by the company's TPM office Oil (fat), so that can effectively reduce the bearing friction loss. 2.2.1.2 reduce the friction loss of the shaft seal device: Before the workshop centrifugal pumps are used to fill the seal, and now vigorously promote the mechanical seal, reduce friction losses, maintenance is also relatively reduced, as of 2009 workshop 10 centrifugal pump by All packing seals are replaced with mechanical seals. 2.2.2 improve the water pump efficiency Centrifugal pump material is basically cast iron, without mechanical processing, thereby increasing the fluid flow loss. Generally can take the following ways to reduce the flow loss: ① than the surface of the pump body painted paint or paint makes the surface smooth and reduce losses. This method is not implemented. ② flow channel should not be too long, otherwise make the loss increase. Workshop 10 pumps are distributed in two pump rooms, 7 old pump houses, 3 new pump houses, all of which are equipped with water tanks before and after the pump house. The pipeline length is moderate, and the flow loss will not increase. 3 impeller turning Turbine turning is a simple and economical pump energy saving measures, with the impeller diameter decreases, flow, lift, power is also reduced, the power will be reduced a lot. Cutting the impeller or removing the original impeller into a smaller impeller of the same diameter is a good way to save energy. This is also the most widely used and effective energy saving measure for centrifugal pumps in the current workshop.    4 speed adjustment Centrifugal pumps are generally selected according to the maximum load, and when the pump head range, then take speed regulation, which is to change the pump operating conditions. Centrifugal pump operating point is determined by the pump characteristic curve and piping system characteristic curve, so to change any one of the characteristic curves can achieve the role of regulation, the current flow control of the pump with regulating valve control, variable speed control and pump The series parallel adjustment. For the current pump flow control mode, the speed control valve control than the cost savings is much larger, through the variable speed regulation, the original power consumption in the valve can be completely avoided, and achieved good energy-saving effect. And through the pump speed control flow is also beneficial to reduce the possibility of cavitation pump. At present, enterprises are demanding more and more on the production unit consumption, and the workshop production makes extensive use of frequency conversion technology to save energy and reduce consumption. Several pumps running water supply in the past few years Matching methods: Two (or more) constant speed pump matching operation (2000 years ago) Inverter unit matches with constant speed pump (2000-2008) Inverter unit single unit operation (since 2008) Three kinds of operating mode of production unit consumption comparison (historical data) The first 2200 kwh / ten thousand tons second 2000 kwh / ten thousand tons or so The third 1650 kwh / ton following Unit production unit consumption calculation method: Consumption = running power unit in this class ÷ the total amount of electricity in this class Power = power meter scale × magnification Workshop different operating unit magnification:     The working principle of the pump shows that the flow of the pump is proportional to the rotational speed of the pump (motor), the lift of the pump is proportional to the square of the rotational speed of the pump (motor), and the pump shaft power is equal to the product of the flow and the lift. Both the pump shaft power and the power supply is proportional to the third power). That is, when the pump speed drops, the shaft power of the pump will decrease to the third power. Therefore, the energy-saving effect of the inverter unit is obvious. Workshop unit matching method 2 # inverter 3200 - 2000 m? / H 1 # inverter unit 2500 - 1000 m? / H 9 # inverter unit 1200 - 600 m? / H When the water consumption for a short time more than the upper limit of the frequency of water supply units, matching a constant speed pump, try not to run at the same time two constant speed pump operation, the workshop is taken to a single run 2 # inverter unit, energy saving The best results. Frequency converter used to adjust the speed of the motor pump flow in the energy saving and improve efficiency have very good results, centrifugal pumps in actual use to reduce energy consumption is a systematic work should start from many aspects, making the pump Can run in the vicinity of efficient operating conditions, will be able to completely reduce the pump energy consumption, to achieve energy-saving purposes.