As an important form of centrifugal pump, the double suction pump is widely used in engineering due to its characteristics of high lift and high flow. The pump impeller is actually composed of two back-to-back impeller and flows from the impeller into a volute. The dual suction pump has the following characteristics: it is equivalent to two single suction impeller in the same diameter while working. The flow of the same impellers can be doubled. The pump shell level open, and the inspection and maintenance is convenient. At the same time, the double suction pump import and export in the same direction and perpendicular to the pump shaft, which is conducive to the installation and installation of pumps and inlet and exit pipes; The impeller structure of the double suction pump is symmetrical, with no axial force and stable operation. In the area of China's Yellow River, the pump station has a high flow rate and high lift, most of which adopt double suction centrifugal pump. The pump station of the south water and north water diversion center has also adopted a double suction pump for water supply.
The structure characteristics of the double suction pump
Compact structure: beautiful appearance, good stability, easy to install.
Smooth operation: the optimal design of double suction impeller reduces the axial force to the minimum, and it has the excellent hydraulic performance of the leaf type, and it has been precision casting, the surface of the pump and the surface of the impeller are remarkably smooth and have remarkable anti-cavitation performance and high efficiency.
Shaft seal: choose BURGMANN mechanical seal or packing seal. There is no leakage for 8000 hours.
Bearings: SKF and NSK bearings are used to ensure smooth running, low noise and long service life.
Installation form: it is not necessary to adjust when assembling, but according to the conditions on site. It includes vertical or horizontal installation.
The reasons for the decrease in the efficiency of double suction pump:
1. Due to the erosion of water flow, the inner wall and impeller of the water pump have become rough and uneven, the friction coefficient of the inner flow of the water pump increases, and the water flow in the pump is very large, and the loss of water head increases. Hydraulic efficiency is reduced.
2. It causes serious fouling or corrosion in the pump case due to the injection of drugs or water quality before the pump. In the pump case, it can increase the thickness of the shell wall by 2 ram, and the inner wall of the pump can form a scaling tumor, which can reduce the volume of the pump volume, and reduce the water flow, and the flow path is rough, and the loss of head loss increases. The product efficiency and hydraulic efficiency are reduced.
3. Due to water pump process of casting defects, such as cavitation corrosion, abrasion, and chemical etching holes or cracks caused the pump flow passage, water produces vortex flow and cause power loss. The hydraulic efficiency is reduced.
4. The cavitation of impeller surface. Because of the negative pressure when the blade is running on the surface of the water, when the pressure Pk < Pva, the cavitation and the surface of the honeycomb are produced, the cavitation of the pump is caused by electrochemical corrosion.
5. The volume loss and mechanical loss. Due to the long time of pump use, mechanical wear and tear can cause leakage and drag increase, so that the volume efficiency and mechanical efficiency are reduced. Due to above reasons, the water pump performance is poor. The operating efficiency is reduced by 2 ~ 5%, which can reduce the water pump efficiency by more than 10%.
The Macromolecule composite material is used:
In the process of the pump, the flow of water in the pump is affected by the friction on the surface of the flow channel and the pump impeller and the viscosity of the water itself. The energy consumed by the pump is mainly used to resist the flow friction and eddy resistance of water surface. The amount of energy that water consumes during the flow (head loss) is the friction that is used to overcome internal friction and the interface of water and equipment. If the surface of the pump and impeller is smooth (this surface is known as hydraulic smooth surface) the surface resistance is small and the energy is small. The surface of the coating is 20 times that of stainless steel after polished surface. This extremely smooth surface reduces the layer of fluid in the pump, thus reduces the internal turbulence of the pump, and reduce the volume loss and hydraulic loss in the pump, and reduce the power consumption. The purpose of reducing the loss of water resistance is to improve the hydraulic efficiency of the water pump, and to some extent, it can improve the mechanical efficiency and the volume efficiency. The compactness of the coating molecular structure can isolate the contact of the air, water and other media and the pump impeller, and minimize the electrochemical corrosion and corrosion. In addition, the essence of polymer composites is high polymer polymer, which has anti-chemical and corrosive effect, which can improve the anti-corrosive effect of the pump, which can greatly enhance the pump resistance to erosion and corrosion resistance.
Adopt new sealing technology
The pump has some energy losses during the working process, including mechanical wear, volume loss and hydraulic loss. Mechanical loss refers to the shaft sealing friction, bearing friction, impeller surface and liquid friction. We use the blu-goo super lubricant to reduce the friction of the shaft sleeve of the pump and the friction of the bearing, so as to improve the efficiency of the pump and reduce the consumption of energy. It is a kind of special inert material with a variety of uses, it is mainly used to reduce metal contact. As a threaded sealing compound, the material is formed as a contact surface between the outer thread and the internal thread, which can protect the connector from friction and wear. At the same time, it can withstand the pressure of 1407 kg/cm, or even wear, corrosion or error machining. The product is also an excellent gearbox additive, which can be formed on the inner parts to reduce friction, gear noise and leakage. It also obviously reduces the torque stress and satisfies the dynamic pressure relief demand. It can be used as a gasket or as a filler, sealed to prevent fluid leakage. It can be applied under the temperature of 316 ℃.