Volume loss of centrifugal Pump
Volume loss of centrifugal pump including seal ring leakage loss, balancing mechanism leakage loss and interstage leakage loss. This article describes the seal ring leakage loss.
In the entrance of the impeller is a seal ring, when the pump works, because the sealing ring on both sides with pressure difference between the side of the approximately impeller outlet pressure side of the impeller inlet pressure, so there will always be a part of the liquid from the impeller to the outlet impeller inlet leak. This part of the liquid in the impeller in obtaining energy, but the liquid did not sent, thus reducing the water supply pump. All the energy used to overcome the leakage of fluid resistance of the seal ring.
Obviously, if the sealing ring diameter larger ,pressure on both sides is more special, the greater the amount of leakage. For stereotypes pump, in order to improve feed efficiency of the pump leakage amount should be permitted in the case of the sealing ring gap is narrowing. Usually approximated total clearance seal ring diameter of 0.002, as Dw = 200 mm, the total clearance of 0.40 mm, when assembled, the sealing ring can not be eccentric too large, otherwise the amount of leakage also increases. The main measures In addition, the sealing ring can be used to increase the resistance method of reducing the amount of leakage, increase the resistance of the seal ring is made of a maze, zigzag, etc., which also increases the length of the sealing ring seal, increasing the resistance along the way.
Ring seal leakage, and in some cases cause disturbance of the impeller inlet, so will the rational design of the sealing ring form.
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How to increase the submersible pump self-priming ability
First, the submersible pump in the pump suction pipe set on the vacuum pump, pump start before the start of the vacuum pump, so that the first water pump filled with water to ensure that the pump automatically and quickly start. This type of water absorption requires a sound automatic control system to ensure proper operation.
Second, relative to the following are also relatively simple: no clogging submersible pump to reduce the water pipe corners, drop height and horizontal interval.
Third, this way need to set up a suction pipe in the pump, the pump in the first run before the tank should be filled with water, the first run after the end of the water tank due to the height of the water pipe height , Although the water level in the pool below the tank surface height, the tank of water will not turn back.
The last way to install the suction end valve at the end of the suction pipe of the submersible pump. The suction valve is actually a check valve, which ensures that the water can only enter the suction pipe from the pool and can not be reversed, so if the suction pipe is filled with water, although the pump axis elevation is higher than the working water level of the pool. The role of the end of the valve, the water pipe will not flow into the pool, the suction pipe has been filled with water, to ensure that the pump can automatically and quickly start.
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The minimum submerged depth of the pump
The minimum submerged depth of the pump is a prerequisite for proper operation of the pump. The samples on the factory are marked with clear data. The Panda pump indicates that the data is calculated on the basis of:
1. According to the pump’s abundance allowance calculation, to ensure that the pump does not occur cavitation.
2. For submersible pumps in the upper part of the motor, if the motor cooling cycle is not installed, the entire motor is immersed in water to cool the motor stator.
3. The minimum submerged depth is to ensure that the pump running, the sink does not occur in the whirlpool, the air is not involved in the import of the pump, and to ensure that the liquid flow into the pump evenly distributed.
Moreover, Nanjing lanshen Pump Corp.LTD. found that some pumping stations due to the flow and inhalation pool conditions are limited, the pump running after the change in the water level is very large, inhalation tank water level, resulting in the actual submerged depth below the minimum submerged depth, resulting in the pump can not run properly, Cavitation. Such as a pumping station, suction pool minimum water level elevation of 1m, up to 4.5m, water depth difference of 3.5m. If the pump station is designed according to the 1m elevation, the whole pumping station is dug deep and the elevation design is raised. The submerged depth is less than the minimum submerged depth.
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Some common troubles of submersible mixer
The impeller is made of cast or stamping, with high precision, high thrust, beautiful appearance, compact structure and compact structure. It adopts the multi-pole motor hybrid series products, direct coupling structure, low energy consumption and high efficiency.
The motor’s submersible mixer stirrer windings are class F insulated with protection class IP68. The use of sewage treatment plant aeration system, greatly reducing the system’s energy consumption, so that the oxygen content was significantly improved, and can effectively prevent. According to process requirements, direct diving mixing can be equipped with baffles.
1.Check the submersible gear box.
Submersible gearbox has high precision and good heat treatment, but it also has the phenomenon of gear teeth and the gear shaft is not axial clearance. We carried out a thorough cleaning of the gearbox and carefully examined gears, gear shafts, bearings. There is no pitting in the inner and outer ring and the surface of the roller, and the whole quality is good. The gears are smooth, no pitting, overlapping, normal backlash, no obvious wear on tooth profile. The radial and axial clearance are normal. Axial clearance is reasonable, hand wheel output shaft free flow, no interference, no abnormal sound. Therefore, the failure of the gearbox is eliminated.
2.Submersible mixer mechanical seal inspection
Mechanical seals are the most prone to failure of submersible fittings, often due to wear and tear of the mechanical seal failure, seal the cavity water. We first disassemble the mechanical seal assembly, which consists of two sets of mechanical seals, the skeleton oil seal, the output shaft, the bearing, the outer cover and the end cap and so on part to carry on the cleaning and the inspection, and inspects the bearing seat and the output shaft size, has not found. The mechanical seal is in place to eliminate the possibility of failure.
Suitable for industrial and municipal sewage treatment plants aeration tanks and anaerobic tanks, pool water cycle and nitrification, nitrogen and phosphorus removal.
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Submersible pumps which suitable for agricultural irrigation
Many industries will use submersible pumps, agricultural irrigation will also use submersible pumps, but the use of agricultural irrigation submersible pumps and most industries, after all, will be different. Now used to irrigate the drains of the land has been rare, but rather the more common submersible pumps for land irrigation, we will look at the use of agricultural submersible pump requirements.
Suitable for agricultural irrigation submersible pumps when installed, the pump should be ramped to reduce the elbow, or install the volute turn, so that the outlet can be facing the pool. As far as possible to shorten the submersible pump pipeline, we remove one meter of steel pipe, ten hours of irrigation work we can save 0.21 kg of diesel, a long time the greater the amount of diesel fuel savings, try to expand the submersible pump outlet diameter , If we put a four-meter-long 10 cm water hose into a 15 cm pipe, we can save 0.5 kg of petrol per ten hours.
In the submersible pump water can be kept clean, we can remove the filter. In order to prevent the impeller ring and axial clearance is not appropriate, we are in use, should be based on the submersible pump pump factory instructions to adjust, for submersible pumps in the pipeline blockage, we have to promptly clear, so as not to affect the submersible pump Normal work to prevent the submersible pump into the gas pump, because the pump intake will reduce the pump water, in order to prevent this situation, we should be in the submersible pump to check the various parts of the maintenance.
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What are the measurement accuracy of the sewage pump?
In response to the customers’ requirements, today we will introduce what is included in the sewage pump measurement accuracy
1.Sewage pump start, diesel engine start, emergency stop, increase or decrease;
2.Electric valve control (control flow);
3.Sewage pump conditions to switch to the implementation of the test process control;
4.Automatic start-up control of the cooling device;
5.Diesel engine water temperature, oil temperature, oil pressure and gear box oil temperature automatic monitoring and alarm.
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Analysis on daily maintenance of submersible pump crankshaft
Crankshaft is an important part of the submersible pump, in the course of the use, it is often damaged, how to try to maintain its life, as we urgently need to solve the problem, then we introduce the submersible pump crankshaft daily maintenance measures:
1.Submersible pump crankshaft normal operation of the submersible pump every 8h maintenance time, by the shift pump workers, every 2h tour check a submersible pump and motor operation.
2.Check the submersible pump oil is in line with the requirements, there are problems in a timely manner to add or replace, to ensure that the lubrication of the normal work.
3.Check and adjust the submersible pump packing letter, and to ensure that the fixed, connecting bolts without loosening.
4.Check the unit vibration operation without abnormal sound, should meet the requirements of this standard, the instrument action sensitive and accurate.
5.Submersible pump crankshaft equipment to deal with leakage and do a good sanitation work.
The above is about the submersible pump crankshaft daily maintenance of the relevant matters related to the introduction, in the daily use of attention to these points will be able to ensure the normal operation of the submersible pump to extend its service life.
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Pay attention when choose submersible pump
Submersible pumps can often be seen in rural areas, which is an important water lifting tool for their livelihoods and farmers’ production. Now on the market regardless of what products are many types, are different technologies and manufacturers, so choose the submersible pump is also pay attention to.
First check the quality of the submersible pump, submersible pump motor has many forms, the use of the motor should be in a sealed state, after the water, the measurement of the motor insulation resistance is qualified, and then the pump to detect Try to test whether the motor is running. Secondly, because the farmers friends are limited by the professional knowledge, not sure the kind of manufacturers and brands of submersible pumps is good. This is the best situation before the purchase of consult the use of submersible pump users or experts in this area, in the choice, to recognize the manufacturer, see the brand and the product of the certificate, do not buy no manufacturers no date No license of the “three no” products, if there is a problem, I will not know who to go to the theory.
Submersible pump is the final to determine its flow and the pump head and other important parameters, the user needs to choose the best lift with the pump name plate on the way, so that the use of affordable, the efficiency can reach the highest. If you choose the pump head is too small, low-lift pump for high-lift work, even if the pumping water, the water will be very small; but the lift is too large, there will be too much traffic, motor overload phenomenon. If it is overload for too long, it will cause the insulation age, and the situation will burn the motor.
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Submersible pump “amulet”
Submersible pumps are a kind of equipment that many industries will use. The general warranty period is one year, but its use environment is relatively bad. In order to reduce the expenses, we must ensure the stability of the submersible pump in order to achieve long-term use purpose. In order to improve the life of the submersible pump, we must ensure that the use of the process, the operation of norms, on this basis to maintain regular maintenance work, will be able to greatly improve the service life of submersible pumps.
In the installation of the time, do not use the cable pump cable overhead, the power cord should not be too long, so as to avoid unnecessary damage. When you send it to the water, do not let the cable too much force, so as to avoid the power line of the fracture. In the process of submersible pumps, do not sink it into the cement, which will affect the cooling effect, which burned the motor winding, in the installation of the time to pay special attention to the motor insulation resistance can not be less than 0.5 megohms, So as to protect the motor very well.
In order to avoid the phenomenon of leakage, the motor will be installed as a thing called the life insurance device, because of its special work, more likely to cause leakage of the situation. In the case of the installation of this component, beyond the rated voltage, it will automatically cut off the power to ensure the safety of operators, but also to avoid accidents.
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The importance of submersible pump characteristics
At present, in the submersible pump fluid pipeline system, the control valve is the corresponding control components, the main role is to use isolation equipment and piping systems, adjust the flow, to prevent the return with the regulation of discharge pressure.
It is important to choose the most suitable control valve for the piping system of the submersible pump, and it is important to understand the performance of the submersible pump and to select the steps and basics of using the submersible pump. Under normal circumstances, there are two characteristics of submersible pump control valve, the use of features and structural characteristics. The use of the characteristics is to determine the main performance of the submersible pump and the use of the scope of the use of submersible pumps are the characteristics of the type of submersible pumps, submersible pump product type, submersible pump main parts of the material and submersible pump transmission The Submarine pump structural characteristics is to determine the structure of the submersible pump length and the overall height of the connection with the pipeline, the form of sealing surface and stem structure and so on.
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