1.Shaft seal overheating Causes and solutions:
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(1) Packing is too tight or friction occurs. Solution: Loosen the packing and check the water seal pipe.
(2) Water seal ring and water seal pipe misaligned. Solution: Realign them.
(3) Poor flushing and cooling. Solution: Check the flushing and cooling circulation pipe.
(4) Mechanical seal failure. Solution: Check every sealing component of the mechanical seal.
2.Excessive rotor oscillation in the fluoroplastic centrifugal pump Causes and solutions:
(1) Improper use, operating conditions deviate from the pump's design conditions. Solution: Strictly follow the technical specifications to operate the pump within the design conditions.
(2) Insufficient balance. Solution: Clean the balance pipeline.
(3) Material of the balance disc and its base does not meet the requirements. Solution: Replace with materials that meet the requirements.
3.Inability to start or high starting load of the fluoroplastic centrifugal pump Causes and solutions:
(1) Abnormal motor or power supply. Solution: Check the power supply and motor condition.
(2) Pump jammed. Solution: Manually turn the coupling to check and, if necessary, dismantle and inspect for common faults in the dynamic and static parts.
(3) Packing is too tight. Solution: Loosen the packing.
(4) Discharge valve not closed. Solution: Close the discharge valve and restart.
(5) Obstruction in the balance pipe. Solution: Clean the balance pipe.
4.Pump does not discharge liquid Causes and solutions:
(1) Insufficient priming (or gas inside the pump not fully discharged). Solution: Prime the pump again.
(2) Incorrect pump rotation direction. Solution: Check the rotation direction.
(3) Pump speed too low. Solution: Check the speed and increase it if necessary.
(4) Strainer clogged, check valve malfunction. Solution: Check the strainer and clear any debris.
(5) Suction head too high or suction tank experiencing a vacuum. Solution: Reduce the suction head or check the pressure in the suction tank.
5.Interruption in fluid discharge after starting in the fluoroplastic centrifugal pump Causes and solutions:
(1) Air leakage in the suction pipeline. Solution: Check the connection of the suction side pipeline and the sealing condition of the stuffing box.
(2) Gas in the suction side not fully discharged during priming. Solution: Prime the pump again.
(3) Sudden blockage in the suction side. Solution: Stop the pump and remove the blockage.
(4) Large amount of gas in the suction. Solution: Check for vortex at the suction inlet and whether the immersion depth is too shallow.
6.Insufficient flow in the fluoroplastic centrifugal pump Causes and solutions:
(1) Increase in static head of the system. Solution: Check the liquid height and system pressure.
(2) Increase in resistance loss. Solution: Check the pipeline and check valve for obstructions.
(3) Excessive wear of the casing and impeller wear ring. Solution: Replace or repair the wear ring and impeller.
(4) Leakage from other parts. Solution: Check the shaft seal and other parts.
(5) Clogging, wear, or corrosion of the pump impeller. Solution: Clean, inspect, and replace as needed.
7.Insufficient head in the fluoroplastic centrifugal pump Causes and solutions:
(1) Impeller installed in reverse (double suction impeller). Solution: Check the impeller.
(2) Liquid density and viscosity do not match the design standard. Solution: Check the physical properties of the liquid.
(3) Operating flow rate too high. Solution: Reduce the flow rate.
8.High power consumption during operation of the fluoroplastic centrifugal pump Causes and solutions:
(1) Friction between impeller and wear ring, impeller and casing. Solution: Inspect and repair.
(2) Excessive flow rate. Solution: Reduce the flow rate.
(3) Increase in liquid density. Solution: Check the liquid density.
(4) Packing is too tight or dry friction occurs. Solution: Loosen the packing and check the water seal pipe.
(5) Bearing damage. Solution: Inspect and repair or replace the bearings.
(6) Excessive speed. Solution: Check the driving machine and power supply.
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(7) Pump shaft misalignment. Solution: Correct the pump shaft.
(8) Error in the axial force balancing device. Solution: Check the balancing holes and whether the return pipe is blocked.
(9) Coupling misalignment or excessive axial clearance. Solution: Check the alignment and adjust the axial clearance.
9.Vibration or abnormal noise in the fluoroplastic centrifugal pump Causes and solutions:
(1) Vibration frequency is 0~40% of the working speed. Causes include excessive bearing clearance, loose axle sleeves, impurities in the oil, abnormal oil quality (viscosity, temperature), foaming of oil due to gas or process fluid, and bearing damage. Solution: Check and take effective measures such as adjusting bearing clearance, removing impurities from the oil, and replacing it with fresh oil.
(2) Vibration frequency is 60%~100% of the working speed. Causes include excessive sealing clearance, loose retaining rings, and damaged seals. Solution: Inspect, adjust, or replace the seals.
(3) Vibration frequency is 2 times the working speed. Causes include misalignment, loose coupling, friction in the sealing device, deformation of the casing, bearing damage, resonant support, and damaged thrust bearings. Solution: Inspect and take effective measures such as repairs, adjustments, or replacements.
(4) Vibration frequency is n times the working speed. Causes include pressure pulsation, misalignment, casing deformation, friction in the sealing, resonant support or foundation, pipeline-machine resonance. Solution: Strengthen the foundation or pipeline.
(5) Very high vibration frequency. Causes include shaft friction, imprecise sealing, loose bearings, abnormal shrink fit, etc. Solution: Strengthen the foundation or pipeline.
10.Bearing overheating in the fluoroplastic centrifugal pump Causes and solutions:
(1) The bearing pad scraping does not meet the requirements. Solution: Re-repair the bearing pad or replace it.
(2) The bearing clearance is too small. Solution: Readjust the bearing clearance or scrape it.
(3) Insufficient lubricating oil or poor oil quality. Solution: Increase the oil quantity or replace the lubricating oil.
(4) Poor installation of bearings. Solution: Check the bearing installation according to the requirements and rectify any deviations.
(5) Cooling water circuit interrupted. Solution: Inspect and repair it.
(6) Bearing damage or looseness. Solution: Repair or replace the bearing. If loose, tighten the relevant bolts.
(7) Pump shaft deformation. Solution: Correct the pump shaft.
(8) Deformation of the slinger ring, the slinger ring cannot rotate, and failure to deliver oil
'' Corrosion-resistant centrifugal pumps are widely used in various industries. Due to the unreasonable model selection, many corrosion-resistant centrifugal pumps are in an unreasonable operating condition, with low operating efficiency and high maintenance costs, resulting in a waste of resources. Due to unreasonable selection, the corrosion-resistant pump cannot be used at all. Otherwise, it often fails and the cost of use is high. Therefore, how to choose a suitable corrosion-resistant centrifugal pump is also a big science.
'' 1. Under normal circumstances, if the customer cannot choose a suitable corrosion-resistant centrifugal pump, he can submit the parameters such as flow, head, liquid properties, etc., and our technicians in Changsha Zhonglian Pumps will select or recommend better corrosion-resistant chemical centrifugal pump products. If the design institute has determined the model of the corrosion-resistant centrifugal pump when designing the installation equipment, configure it according to the requirements of the design institute.
2. According to the arrangement of the device, terrain conditions, water level conditions, and operating conditions, determine the choice of horizontal, vertical and other types (pipeline, submersible, submerged, non-clogging, self-priming, gear, etc.) Corrosion resistant centrifugal pump.
''3, according to the nature of the liquid medium, determine whether the clean water corrosion-resistant centrifugal pump, hot water corrosion-resistant centrifugal pump, oil-resistant centrifugal pump, chemical corrosion-resistant centrifugal pump or impurity corrosion-resistant centrifugal pump, or use non-blocking corrosion-resistant centrifugal pump.
'' Corrosion-resistant centrifugal pumps installed in explosion areas should use corresponding explosion-proof motors according to the explosion area grade.
4. According to the flow rate, determine whether to choose a single-suction corrosion-resistant centrifugal pump or a double-suction corrosion-resistant centrifugal pump; according to the height of the head, choose a single-stage corrosion-resistant centrifugal pump or a multi-stage corrosion-resistant centrifugal pump, high-speed corrosion-resistant pump or low-speed corrosion-resistant pump .
'' 5. Determine the specific model of the corrosion-resistant centrifugal pump
After determining what series of corrosion-resistant pumps to choose, you can press the maximum flow rate (when there is no maximum flow rate, usually 1.1 times the normal flow rate can be taken as the maximum flow rate), and take the two heads after magnifying 5%-10% of the margin The main parameters of performance, the specific model is determined on the type spectrum or series characteristic curve. The operation is as follows:
Using the characteristic curve of the corrosion-resistant centrifugal pump, find the required flow value on the abscissa, and find the required head value on the ordinate, draw a vertical or horizontal line from the two values ''up and to the right, and the intersection of the two lines just falls on the characteristic curve Above, the corrosion-resistant centrifugal pump is the pump to be selected, but this ideal situation is generally rare, and the following two situations are usually encountered:
The first type: the intersection point is above the characteristic curve, which indicates that the flow meets the requirements, but the head is not enough. At this time, if the head is the same, or the difference is about 5%, it can still be used. Corrosion of fluoroplastic pumps. Or try to reduce the pipeline resistance loss.
The second type: the intersection point is below the characteristic curve, and this model is preliminarily determined within the fan-shaped trapezoid range of the characteristic curve of the corrosion-resistant centrifugal pump, and then according to the difference in the head, it is decided whether to cut the impeller diameter. If the difference in the head is very small, no For cutting, if the head differs greatly, cut the impeller diameter according to the required Q, H, and ns and cutting formula. If the intersection does not fall within the range of the fan-shaped trapezoid, a corrosion-resistant fluoroplastic pump with a smaller head should be selected. When choosing corrosion-resistant fluoroplastic pumps, sometimes it is necessary to consider the requirements of the production process and choose different shapes of Q-H characteristic curves.
6. After the model of the corrosion-resistant centrifugal pump is determined, the physical and chemical medium of the transporting medium is similar to the corrosion-resistant centrifugal pump of water. You need to go to the relevant product catalog or sample, and make corrections according to the performance table or performance curve of the model, and see the normal operating point Does it fall in the priority working area of ''the corrosion-resistant centrifugal pump? Is the effective NPSH greater than (NPSH). Can the geometric installation height be modified by NPSH in reverse?
7. For liquids with a viscosity greater than 20mm2/s (or a density greater than kg/m3), the water experimental characteristic curve must be converted into a performance curve of the viscosity (or density), especially for the suction performance and input power Perform careful calculations or comparisons.
8. Determine the number and standby rate of corrosion-resistant centrifugal pumps:
Generally, only one anti-corrosion centrifugal pump is used for normal operation, because a large anti-corrosion centrifugal pump is equivalent to two small anti-corrosion pumps working in parallel (referring to the same head and flow), and the efficiency of the large pump is higher than that of the small anti-corrosion centrifugal pump. Therefore, from the perspective of energy saving, one corrosion-resistant centrifugal pump should be selected instead of two small pumps. However, in the following situations, two corrosion-resistant fluoroplastic pumps can be considered in parallel:
''The flow rate is very large, and a corrosion-resistant centrifugal pump cannot reach this flow rate.
'' For large corrosion-resistant centrifugal pumps that need a 50% standby rate, two smaller pumps can be changed to work, and two standby (three in total).
''For some large-scale corrosion-resistant centrifugal pumps, pumps with 70% flow requirements can be used in parallel operation. No spare pump is required. When one pump is overhauled, the other pump still bears 70% of the production.
'' For corrosion-resistant centrifugal pumps that need to run continuously for 24 hours, three pumps should be spared, one for operation, one for standby, and one for maintenance.
''9. Determine the number and spare rate of corrosion-resistant centrifugal pumps:
Generally, only one anti-corrosion fluorine pump is used in normal operation, because a large pump is equivalent to two small pumps working in parallel (referring to the same head and flow), and the efficiency of the large pump is higher than that of the small pump, so from the perspective of energy saving It is better to choose one large pump instead of two small pumps, but in the following situations, you can consider two pumps to cooperate in parallel:
''The flow rate is very large, and a corrosion-resistant centrifugal pump cannot reach this flow rate.
'' For large pumps that need a 50% standby rate, two smaller pumps can be changed to work, and two standby (three lifts in total).
'' For some large-scale corrosion-resistant centrifugal pumps, pumps with 70% flow requirements can be used in parallel operation. No spare pump is needed. When one pump is overhauled, the other pump still bears 70% of the production.
'' For corrosion-resistant centrifugal pumps that need to run continuously for 24 hours, three pumps should be spared for operation, one for standby and one for maintenance.
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