Submersible sewage pump working principle analysis

Submersible sewage pump is a pump and motor Siamese, and at the same time submerged work under the pump products, compared with the general horizontal pump or vertical sewage pump, sewage pump clearly has the following advantages: 1. Structure Compact, small footprint. Submersible sewage pump submerged work, it can be installed directly in the sewage tank, without the need to build a dedicated pump room for the installation of pumps and machines, you can save a lot of land and infrastructure costs. 2 installation and maintenance easy. Small sewage pump can be freely installed, large sewage pumps are generally equipped with automatic coupling device can be automatically installed, installation and maintenance quite convenient. 3. Continuous operation for a long time. Sewage pump pump and motor due to coaxial, short shafts, rotating parts light weight, so the bearing load (radial) is relatively small, life expectancy much longer than the average pump. 4. There is no cavitation damage and irrigation water and other issues. Especially after the point to the operator has brought great convenience. 5. Vibration noise, low motor temperature, pollution-free environment. It is because of the above advantages, sewage pump has been more and more people's attention, the use of a more and more wide range from the original purely for the transport of fresh water to the present can transport a variety of domestic sewage, industrial wastewater, construction sites Drainage, liquid feed and more. In municipal engineering, industry, hospitals, buildings, restaurants, water conservancy construction plays a very important role in all walks of life. Status of sewage pump: Because of its simple installation, small footprint, easy maintenance and no noise, submersible sewage pump is widely used in municipal engineering, factories, commerce, hospitals, hotels, residential areas and other sewage discharges. Sewage pumps currently on the market are mostly vertical layout, pump and motor coaxial, so that the weight of the rotating parts and the impeller to withstand the same direction of the hydraulic pressure; Second, the submersible sewage pump is used in the sewage, sewage transport Medium contains impurities, sludge and other substances; Third, the submersible sewage pump is a centrifugal pump in its operation, the power is always increased with the flow rate increases, when the flow exceeds the design flow and reaches a certain value, the motor It will be burnt due to overload. Sewage pump reliability needs to be strengthened, therefore, to improve the technical content of their products manufacturers in the future development of the main direction. At present, the submersible sewage pumps in China are mainly manufactured and manufactured by domestic manufacturers, and a small part of their products are imported from abroad. Improve the technological content of products, strengthen the market competitiveness of products to promote the development of the industry. The current form of view, China's sewage pump market is very broad. But everything is divided into two parts, the most critical issue for the sewage pump is the reliability issue, because the sewage pump is used under the liquid occasions; the medium is transported with some mixed liquid containing solid materials; pump and The motor is in close proximity; the pump is upright and the weight of the rotating part is in the same direction as the impeller is subjected to water pressure. These problems make the sewage pump in sealing, motor carrying capacity, bearing arrangement and selection requirements than the average sewage pump is higher. In order to improve the life of the sewage pump, most manufacturers at home and abroad are now on the pump protection system think of a way that the pump leaks, overload, over temperature and other failures can automatically alarm and automatically shut down for repair. However, in our opinion, it is necessary to set up a protection system in the sewage pump, which can effectively protect the safe operation of the electric pump. However, this is not the crux of the problem. The protection system is only a remedy after a pump failure. It is a relatively passive approach. The crux of the problem should be from the very beginning, to completely solve the pump in the sealing, overload and other issues, this is a more proactive approach. To this end, we apply the sub-impeller hydrodynamic sealing technology and pump no-overload design technology to the submersible sewage pump, greatly improving the pump seal reliability and carrying capacity and prolonging the service life of the pump. Impeller hydrodynamic sealing technology applications: the so-called vice impeller Hydrodynamic seal refers to the impeller in the pump near the back of the rear cover near the coaxial installation of an open impeller. When the pump is working, the auxiliary impeller rotates with the pump main shaft, and the liquid in the auxiliary impeller will also rotate together. The rotating liquid will generate an outward centrifugal force that on the one hand withstands the liquid flowing to the mechanical seal and lowers the mechanical Sealing pressure. On the other hand prevent the solid particles in the medium from entering the friction pair of the mechanical seal, reduce the abrasion of the mechanical seal and prolong the service life of the mechanical seal. In addition to sealing the secondary impeller play a role, but also can play a role in reducing the axial force in the submersible sewage pump axial force is mainly caused by the liquid pressure on the impeller pressure force and the entire rotating part of the composition of gravity, which The direction of action of the two forces is the same, the resultant force is formed by the sum of two forces. It can be seen that in the case of identical performance parameters, the axial force of the submersible sewage pump is larger than that of the horizontal ones, and the balance is more difficult than the vertical ones. Therefore, in the submersible sewage pump, the bearing is easy to damage the reason is also a great relationship with the axial force. If the deputy impeller is installed, the direction of the liquid pressure exerted on the impeller is opposite to the resultant force of the above two forces, so that a part of the axial force can be canceled and the bearing life extended. However, there is also a disadvantage of using an aero-impeller seal system that consumes about 3% of the energy on the aero-impeller, but as long as the design is reasonable, this loss can be reduced to a minimum. Sewage pump over-current part of the design of the application of technology: In a general centrifugal pump, the power is always increased with the flow rate increases, that is, the power curve is an increase with the flow curve, which pump The use of this pump poses a problem: when the pump is operating at the design point of operation, the pump's power is generally safe to use, as it is generally less than the rated power of the motor; however, as the pump head decreases, the flow rate increases (As can be seen from the pump performance curve), the power also increases. When the flow rate exceeds the design point flow and reaches a certain value, the pump input power may exceed the motor rated power and cause the motor overload and burn. Motor overload operation either protects the system from stopping the pump; otherwise, the motor is burnt out due to a failure of the protection system. Pump head is lower than the design conditions of the use of head lift, in practice are often encountered, a situation is the pump selection, the pump lift election too high, but the actual use of the pump is to reduce head Use; the other case, in the use of the pump is not good to determine the operating point, in other words, the flow of the pump need to be adjusted frequently; there is another case where the pump needs to be changed frequently. These three conditions can overload the pump and affect the reliability of the pump. It can be said that the scope of use of pumps that do not have a full lift feature, including a blowdown pump, can be greatly limited. The so-called full head characteristic (also known as no overload characteristics) refers to the power curve increases with the flow rate increases very slowly, more desirably when the flow rate increases to a certain value, the power will not only rise again, but will have Drop, that is, the power curve is a hump curve, if so, we simply select the motor rated power slightly more than the hump point power value, then the flow of 0 to the maximum flow of the entire range, whether you are in that one Operating conditions point, the pump power will not exceed the motor power and the pump overload, with this performance of the pump, either selection or use, will be very convenient and reliable. In addition the motor power is not too big, you can save considerable equipment costs. Drainage pumps used in buildings include submersible sewage pumps, submersible drainage pumps, vertical sewage pumps and horizontal sewage pumps. As the general site of the building is smaller, the displacement is not large, the drainage pump can give priority to the submersible sewage pump and submerged drainage pump, which submerged sewage pump is generally used in important places; vertical sewage pump and horizontal sewage pump required to set the interval The basis of the earthquake, self-filling suction, and occupy a certain site, it is less used in the building. Drainage pump flow should be designed according to the life of the second flow of water selection: 1, when the displacement adjustment, according to the life of the largest hour of discharge selected. Fire elevator pool drain pump flow rate of not less than 10L / s. Drainage pump lift by lifting height, pipe loss calculation is determined, then add a certain free head. Free head should adopt 0.02 ~ 0.03MPa. Drainage pump suction pipe and outlet pipe flow rate should not be less than 0.7m / s, and should not be greater than 2.0m / s. Public buildings should be used for each living drainage cistern as a unit to set up a spare pump, usually should be run interactively. Basement, equipment room, garage flushing the ground drainage, if there are two or more than two drainage pump equipment pump. 2, when the pool can not set the accident drain, the pump should have uninterrupted power supply; 3, when the drainage pipe can be closed, may not provide uninterrupted power supply, but should set the alarm device. 4, when upgrading the sewage and waste water with larger impurities, the submersible sewage pump outlet pipes in different sumps should not be combined and discharged. 5, when to enhance the general wastewater, according to the actual situation to consider different submersible sewage pump pool outlet pipe merged. When two or more pumps share one outlet pipe, a valve and a check valve shall be installed on each outlet pipe of the pump. A single pump drainage may occur when the backflow should be set check valve. Do not allow the pressure drain and the building gravity drainage pipe merged discharge. 6, when the submersible sewage pump to enhance large debris, the submersible sewage pump should be equipped with a comminution device; when upgrading with more fibrous waste water, should adopt a large channel submersible sewage pump. 7, When the motor power is greater than or equal to 7.5kW or the outlet pipe diameter is greater than or equal to DN100, the pump can be used to fix the auto-coupling device; 8. When the submersible sewage pump motor power is less than 7.5kW or the outlet pipe diameter is less than DN100, Hose mobile installation. Sewage collection pond submersible sewage pump drainage, water pumps should be set fixed auto-coupling device to facilitate pump maintenance. Drainage pump should be able to automatically start and stop and on-site manual start and stop. Multiple pumps can be alternately operated in parallel, but also can be put into operation in stages. Sewage pump species: 1. Large diameter non-clogging submersible sewage pump 2. With a knife automatic cutting cloth, weeds automatically stir the submersible sewage pump 3. Pump installed at the water's self-priming sewage pump 4. Submersible sewage Pump - the pump body can sneak into the raw material 5. Corrosion and abrasion resistance Good mortar pump is also a sewage pump. Sewage pump description: Sewage pump the use of: 1, the discharge of wastewater units. 2, urban sewage treatment plant emissions system. 3, subway, basement, air defense system drainage station. 4, hospitals, hotels, high-rise building sewage discharge. 5, residential sewage drainage station. 6, municipal engineering, construction sites in the discharge of thin mud. 7, water plant water supply device. 8, farm wastewater discharge and rural farmland irrigation. 9, exploration and mining and water treatment equipment package. 10, instead of shouldering the pick person, to send the river mud. Sewage pump features: 1, the use of a unique single-leaf or double-vane impeller structure, greatly improving the ability of sewage through the pump diameter of 5 times the fiber material and the diameter of the pump diameter of about 50% of the solid particles. 2, the mechanical seal with a new type of hard and decay resistant tungsten carbide material, while the seal improved double seal, making it long-term oil chamber operation, the pump can run more than 8000 hours of safe operation. 3, The overall structure is compact, small size, small noise, significant energy-saving effect, easy maintenance, without building a pump room, dive into the water to work, greatly reducing project costs. 4, the pump seal oil chamber is equipped with high-precision anti-interference leakage detection sensor, and stator windings embedded in the thermal components, absolute protection of the pump motor. 5, According to user needs with automatic safety control cabinet, the pump leakage, leakage, overload and over-temperature and other absolute protection, improve product safety and reliability. 6, the float switch can be based on changes in liquid required to automatically control the pump start and stop, without special care, the use of extremely convenient. 7, according to user needs with dual rail automatic coupling installation system, which brings great convenience to installation and maintenance, people do not have to enter the sewage pit for this purpose. 8, can be used in the whole head range, and to ensure that the motor will not be overloaded. 9, there are two different installation methods, fixed automatic coupling installation system, mobile free installation system. Sewage pump models Application: Sewage pumps are widely used in various fields, the sewage pump has the ability to transport liquids containing hard solids, fibrous materials, and particularly dirty, sticky and slippery liquid characteristics, the sewage pump is widely used in Mines, paper, printing and dyeing, environmental protection, oil refining, petroleum, chemical, farm, dyeing, wine, food, fertilizer, coking plant, construction, marble factory, mud, quicksand, mud pond, sewage pond, , Loading and suspended matter in the sewage treatment. There are many types of sewage pump, the use of a variety of occasions to use, first to distinguish between submersible and ordinary sewage pump it, the submersible pump motor and pump directly into the sewage pool inside, while the sewage pump is installed on the ground.