End-suction pumps are actually single-suction pumps. Both end-suction centrifugal pumps and double-suction centrifugal pumps are similar, with similar advantages and disadvantages. The only difference between the two is: the water inlet on the impeller side is end-suction (single suction), and the two Side water is called double suction. What are the specific differences between end-suction centrifugal pumps and double-suction centrifugal pumps? Let's compare and analyze them.
A. Different features
1. Double suction pump: equivalent to two single suction impellers of the same diameter working at the same time, the flow can be doubled under the same outer diameter of the impeller; the pump casing is opened in the horizontal, easy to check and maintain
2. End-suction pump: Single-stage end-suction centrifugal pump is a simple type of centrifugal pump. This kind of pump generally has a small flow rate and is mostly a small pump.
B. Different composition
1. Double-suction centrifugal water pump: It is composed of two back-to-back impellers, and the water flowing from the impellers merges into a volute.
As an important form of centrifugal pump, double-suction pump is widely used in engineering because of its high lift and large flow. The impeller of this pump type is actually composed of two back-to-back impellers, and the water flow from the impeller merges into a volute. The double-suction pump has the following characteristics: it is equivalent to two single-suction impellers of the same diameter working at the same time, and the flow can be doubled under the same outer diameter of the impeller; the pump casing is opened horizontally, which is convenient for inspection and maintenance. The inlet and outlet of the suction pump are in the same direction and perpendicular to the pump shaft, which facilitates the arrangement and installation of the pump and the water inlet and outlet pipes; the impeller structure of the double suction pump is symmetrical, without axial force, and runs smoothly. In the areas along the Yellow River in my country, pumping and irrigation pumping stations have large flow and high lift, and most of them use double-suction centrifugal pumps.
2. End suction centrifugal water pump: Single stage means that there is only one stage impeller in the pump, and single suction means that water is sucked in from one side of the impeller.
The end suction pump sucks in horizontally and axially, and discharges upward and radially. The pump is a suspension structure, and the rotor parts can be returned for maintenance without disassembling the inlet and outlet pipelines during maintenance. The pump is connected to the motor through a common elastic coupling or an extended elastic coupling, and the shaft seal of the pump is sealed with soft packing. The bearing is a single row radial ball bearing, which is lubricated by lubricating oil. From the motor end, the pump rotates in a clockwise direction.
working principle:
When the end-suction pump is started, the pump shaft drives the impeller to rotate at a high speed, forcing the pre-filled liquid between the blades to rotate. Under the action of inertial centrifugal force, the liquid moves radially from the center of the impeller to the outer periphery. The liquid gains energy during the movement process of flowing through the impeller, the static pressure energy increases, and the flow increases. After the liquid leaves the impeller and enters the pump casing, due to the gradual expansion of the flow passage in the casing and the extinguishing speed, part of the kinetic energy is converted into static pressure energy, and finally flows into the discharge pipeline in a tangential direction. Therefore, the volute pump casing is not only a component that collects the liquid flowing out of the impeller, but also a power transfer device. When the liquid is thrown from the center of the impeller to the outer periphery, a low pressure zone is formed in the center of the impeller, and the liquid is sucked into the center of the impeller under the action of the total potential energy difference between the liquid level of the storage tank and the center of the impeller. Relying on the continuous operation of the impeller, the liquid is continuously sucked and discharged. The mechanical energy obtained by the liquid in the centrifugal pump is ultimately manifested as an increase in static pressure energy.
End-suction centrifugal pump means that only one end of the impeller enters water, while the double-suction pump means that both ends of the impeller enter water, that is, two inlets.
C.The structure is different
1. The double-suction centrifugal pump is more suitable for conveying large flow and requires stable operation. When the flow rate of the pump is very high, if it is a single-suction pump, it must have a large pump inlet and outlet diameter. At the same time, the speed should not be too large, and it should be stabilized at about 1450rmp. If a double-suction pump is used, the size and weight of the pump can be relatively reduced, the speed can be increased, and the volumetric efficiency can be increased.
2. The anti-cavitation ability of the double-suction pump is stronger than that of the single-suction pump. Since the medium is sucked in at both ends of the impeller, hydraulic symmetry will be formed, so that the balanced axial thrust of the double-suction pump is better than that of the single-suction pump, and it runs more smoothly. Moreover, the flow rate of the medium is low, and the impeller is not prone to cavitation.
Double suction pump mainly sucks the medium at both ends of the impeller, and there is a sealed cavity on each side of the impeller. Instead of the pump has two suction ports. The anti-cavitation ability of double suction pump is stronger than single suction pump. Since the medium is sucked in at both ends of the impeller, hydraulic symmetry will be formed. In this way, the balanced axial thrust of the double-suction pump is better than that of the end-suction pump, and it runs more smoothly. Moreover, the flow rate of the medium is low, and the impeller is not prone to cavitation. However, the double-suction pump has one more sealed cavity than the single-suction pump, so its cost is relatively high.
D.Different application scenarios
End suction pump is a kind of water pump that is widely used in agriculture. Double suction pumps are mostly used for water supply and drainage in mines, cities, power stations, and various water conservancy projects.
End suction pumps generally have a relatively small flow rate. The advantage is that the same flow rate, the end suction volume is small, but the axial force is large, and the bearing burden is large. Compared with double-suction pumps, there are many limitations. In terms of use, the advantages of double-suction sewage pumps are more obvious.
