Industry News

Comparison of the scope and characteristics of the pump 2

2019/04/11

Axial flow pump


The axial flow pump impeller is equipped with 2 to 7 blades and rotates in a circular tubular pump casing. The pump casing on the upper part of the impeller is provided with fixed vanes to eliminate the rotational movement of the liquid, to make it move axially, and to convert the kinetic energy of the rotary motion into pressure energy. Axial pumps are usually single-stage and a few are made in two-stage. The flow range is very large, ranging from 180 to 360,000 cubic meters per hour; the lift is generally below 20 meters. The axial flow pump is generally vertical, the impeller is submerged under water, and there is also a horizontal or inclined axial flow pump. When the impeller installation position of the small axial flow pump is higher than the water surface, it needs to be started by the vacuum pump exhaust water. The blades of the axial flow pump are of fixed and adjustable construction. The working conditions of the large axial flow pump (mainly the flow rate) often need to be changed greatly during operation. Adjusting the installation angle of the blade enables the pump to operate in a high efficiency zone under different working conditions. The blade mounting angle of a small pump is generally fixed. The axial flow pump is the one with the highest number of revolutions in the power pump, and the specific number of revolutions is 500 to 1600. The pump flow-lift, flow-shaft power characteristic curve is steep in the small flow area, so it should be avoided in this unstable small flow area. The axial pump has the highest shaft power at zero flow, so the pump must be opened before the start to reduce the starting power. The axial flow pump is mainly suitable for low lift and large flow situations, such as irrigation, drainage, dock drainage, water level adjustment of canal locks, or as a large circulating water pump for power plants. The axial pump with higher lift (made in two stages if necessary) can be used for water jet propulsion of shallow water vessels.


Vortex pump


A vortex pump (also known as a vortex pump) is a vane pump. Mainly composed of impeller, pump body and pump cover. The impeller is a disc with the blades on the circumference arranged radially evenly. An annular flow path is formed between the pump body and the impeller, and the suction port and the discharge port are both at the outer circumference of the impeller. There is a partition between the suction port and the discharge port, thereby isolating the suction port and the discharge port.


We divided the liquid in the pump into two parts: the liquid between the blades and the liquid in the flow channel. When the impeller rotates, the circumferential velocity of the liquid in the impeller is greater than the peripheral velocity of the liquid in the flow channel by the centrifugal force, so that the "annular flow" shown in Fig. 1 is formed. Since the liquid from the suction port to the discharge port follows the impeller, the combination of these two movements causes the liquid to produce the same "longitudinal vortex" as the impeller. Thus the name of the vortex pump is obtained. It should be particularly pointed out that the circumferential velocity of the liquid particle in the pump flow channel is smaller than the circumferential speed of the impeller.


During the longitudinal vortex, the liquid particles enter the impeller blades multiple times, and the energy is transmitted to the liquid particles in the flow passage through the impeller blades. Each time the liquid particle passes through the blade, it gains an energy. This is also the reason why the vortex pump has a higher lift than other vane pumps with the same outer diameter of the impeller. Not all liquid particles pass through the impeller, and as the flow increases, the "annular flow" weakens. When the flow rate is zero, the "circular flow" is the strongest and the lift is the highest. The liquid in the flow channel transfers energy through the impact of the liquid. At the same time, it also causes a large impact loss, so the efficiency of the vortex pump is relatively low.


The single-stage direct-connect vortex pump is used for sucking clean water or liquid with physical and chemical properties similar to water. The liquid temperature is not more than 60, which is often used for boiler feed water, in shipbuilding, textile, chemical, metallurgical, mechanical manufacturing, Aquaculture, fixed fire control, heat exchanger groups, agricultural remote sprinkler irrigation and other departments have a wide range of applications. Vortex pumps are commonly used in boiler feed water, and are widely used in shipbuilding, textile, chemical, metallurgy, machinery manufacturing, aquaculture, fixed fire control, heat exchanger groups, agricultural remote sprinklers and other departments.


Reciprocating pump


When the piston moves from left to right, a negative pressure is formed in the pump cylinder, and the liquid in the storage tank enters the pump cylinder through the suction valve. When the piston moves from right to left, the liquid in the cylinder is squeezed, the pressure] increases, and is discharged by the discharge valve. The piston reciprocates once, each inhaling and discharging a liquid, called a working cycle; this pump is called a single-action pump. If the piston is reciprocated once, each inhaled and discharged liquid is called a double acting pump. The piston moves from one end to the other and is called a stroke.


Applicable to: wastewater discharge from enterprise units, discharge system of urban sewage treatment plants, subways, basements, drainage lines for sewage control systems, hospitals, hotels, and high-rise buildings.


Rotor pump


The rotor pump is also called a colloid pump, a cam pump, a three-leaf pump, a universal pump, etc., and the rotor pump belongs to a volumetric pump. It achieves the purpose of transporting fluid by means of periodic transformations of a plurality of fixed volume delivery units in the working chamber. The mechanical energy of the prime mover is directly converted into the pressure energy of the transport fluid by the pump. The flow rate of the pump depends only on the volume change of the working chamber and its frequency of change per unit time, and (theoretically) is independent of the discharge pressure; the rotor pump is working. The process is actually a pair of rotors that rotate synchronously. The rotor has a pair of synchronous gears in the casing for driving, and the rotor is rotated in the opposite direction by the main and auxiliary shafts. The volume of the pump is varied to create a higher degree of vacuum and discharge pressure. Particularly suitable for the delivery of hygienic media and corrosive, high viscosity media.


The working principle of the positive displacement pump (rotary type)


The power is transmitted to the gear through the shaft, and a pair of synchronous gears drive the pump blades to perform synchronous reverse rotation movement, so that the inlet zone produces a real port, and the medium is sucked in. As the pump blade rotates, the medium is sent to the outlet, and the rotation continues, and the oral volume is discharged. It becomes smaller and generates pressure (outlet high pressure zone) to output the medium. This type of pump is suitable for high viscosity media due to the low volume of the volumetric pump, the high self-priming ability, and the poorly flowable high viscosity medium, which has sufficient time and speed to fill the cavity. The inner sealing surface of the pump. The diarrhea is small, so the pump is more efficient, up to 70%, and can reach the high-pressure delivery medium, and also has good adaptability to the medium with lower viscosity.


Classification and characteristics of volumetric pumps


The positive displacement pump is divided into two types: reciprocating type and rotary type. Compared with the reciprocating positive displacement pump, the rotary type pump has no suction and discharge valves, and does not go to the reciprocating pump. Because of the high viscosity liquid to the valve The normal work has an effect, and the pump efficiency decreases rapidly as the viscosity increases. Moreover, when the viscosity of the conveying liquid is increased, the number of revolutions of the pump is lower than that of the reciprocating pump. Therefore, when the viscosity of the liquid is highly transported or the viscosity of the liquid changes greatly, it is more preferable to use a rotary solvent pump than to use a reciprocating positive displacement pump. Rotary volumetric pumps are divided into gear pumps, rotary piston pumps, screw pumps, and vane pumps. It has the characteristics of low number of revolutions, high efficiency, strong self-priming ability, stable operation, and partial pump preheating. It is widely used for the transportation of high viscosity media. Disadvantages: large floor space, large construction investment, large volume and heavy weight.


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