Vertical long axis pump is a new generation of energy-saving environmental protection lifting pump developed in recent years. It is a special product designed for metallurgy, mining, power, petrochemical and other industries. Mainly responsible for the use of iron oxide, sediment particles, oil pollution of the recycled water or sewage, the use of medium temperature is less than 80 degrees, liquid solid mixture of solid particles in the volume of not more than 10%. The pump has many advantages, energy saving, high efficiency is its biggest advantage. At the same time, the pump also has some shortcomings, mainly is the sleeve coupling assembly is difficult, time-consuming, causing parts of the waste, increase the cost of production.

To enhance the circulating water as an important part of rolling system, vertical long shaft pump failure, will be the direct result of production disruptions, especially the underground installation of the pump body, when circulating water cannot ascend to the horizontal flow tank, which can submerge pump, burning motor, resulting in major production equipment accident.

1 Structure and working principle

Structure of 1.1 long axis pump

The vertical axis of the pump is composed of four parts, namely, the transmission device part, including elastic pin coupling, motor shaft, drive shaft, impeller, shaft coupling (sleeve coupling), adjusting nut, thrust bearings, guide bearings, bushings and other parts; energy transfer, including filter, suction, impeller, guide vane and water; some, including lifting pipe, tube, guide bearing body, the water pipe; lubrication part, sliding bearing pump using 0.3MPa clean water rinse, the guide bearing lubrication cooling.

1.2 working principle and characteristics

The working principle of vertical long axis pump is driven by a motor drive shaft and the rotation of the impeller, the liquid to obtain energy through the impeller, the water section of the guide vane body along the flow between the protective tube and the lifting pipe, vertical upward flow from the outlet. It has the following characteristics:

The advanced hydraulic model design, bidirectional impeller sealing ring has a pump shaft, a thrust bearing, middle and lower the 4F bearing, so as to ensure the smooth operation of rotating shaft, avoiding swing and vibration; thrust bearing for water bath lubrication, the 4F bearings are refined by compression molding with self-lubricating, anti the corrosion and shock absorption function, while using external washing and lubricating cooling water, improve the life expectancy; between the impeller shaft and the drive shaft and the motor shaft connected with sleeve coupling clasp type key drive reliable transmission; the pump body adopts a double-layer structure, 0 type sealing ring between the tube and the bearing. The rotor and the channel completely separated, the conveying medium completely separated from the water lubrication, so as to ensure the long service life of the pump.

Vertical long shaft pump head is still working under water, the pump depth is generally a few meters, some as high as ten meters, so the use of a shaft is not realistic. The current domestic production of long axis pump, whether by sliding bearings or rolling bearings, the pump shaft is divided into several sections, each section between the coupling sleeve (sleeve coupling) connection, said motor shaft which is connected with a motor, the impeller is arranged at the lower part of the leaf shaft, located in electric collectively between the crankshaft and the impeller shaft the drive shaft.

1.3 sleeve couplings and their functions

Sleeve coupling function mainly has two aspects: one is to connect each axis, and to ensure that each concentric shaft; two is the transmission of torque generated by the motor torque to the impeller to pass through each shaft, sleeve coupling, the impeller on the liquid work, so the sleeve coupling is very important parts in the long axis pump. Sleeve coupling and shaft matching accuracy requirements are quite high, generally H7 / H6, with its surface roughness of more than Ra1.6, the shaft neck and sleeve coupling round must be fine grinding.

2, the existing problems and analysis, because the sleeve coupling and shaft clearance is very small,

During the repair process are generally used to destroy the law, or by cutting and hammering method to destroy the sleeve coupling, the increase of the cost of heavy workload, long cycle, high labor intensity of workers.

The clearance between the inner hole of the outer sleeve and the outer circle of the shaft neck is a fixed value. From the point of view of use, this gap is the smaller the better (even interference fit), so that the whole pump rotor concentricity and rigidity are better, the pump runs smoothly, long service life. Therefore, the sleeve coupling and shaft assembly is an important link. Improvements must be made to the sleeve couplings.

3, the improvement measures on the sleeve coupling improvement principle is, that is to ensure the coaxial shaft, but also can effectively transfer torque, demolition convenient and quick. In the process of implementation, it should be ensured that the quality of the metal to be removed, drilled and tapped is equal to the quality of the bolt and the elastic washer. Only in this way can the balance be ensured and the additional vibration will be avoided. If the quality of the removal is not equal to that of the added mass, the action balance test must be carried out to eliminate the unbalanced weight. Because one side of the sleeve coupling is cut open, it is very easy to assemble. Just a half clasp in two groove, the first coupling sleeve is sheathed on the shaft (with one side open, in the range of elastic deformation, the coupling sleeve is sheathed on the shaft is relatively easy), then use the assembly in place, inner six angle bolt sleeve coupling is opened on one side of the fixed die. And with the bolt hole seal sealant. In case of failure, remove the sealant and unscrew the bolt.

4, the improved effect, the improved sleeve coupling can be effectively eliminated

The clearance between the couplings allows them to reach zero at last. The rotor of the neutral good, good rigidity, and give full consideration to the balance of sleeve coupling, reduces the production cost; long axis pump fastening after transformation is good, stable operation, low vibration noise, MTBF is greatly improved.