First, single-stage single-suction cantilever centrifugal pump structure;
1) The chemical pump is a single-stage single-suction centrifugal pump, pump casing is volute type. Axial suction radial discharge, the pump shell as the center support type, the connection of the pump housing and the base with transverse connection sliding pin expansion system, thus ensuring the pump after thermal expansion of the neutral.
2) pump shell as the center support type, do not have to remove the flange of the entrances and exits when overhauling, overhauling more convenient.
3) Impeller with a wear ring, impeller wear, only replace the wear ring, reducing the cost of overhauling. In addition there is a balance hole in the impeller, you can automatically balance the axial thrust.
4) self-priming pump shaft supported by the rolling bearings, the use of shrink-fitting method (or heating method) to ball bearings and roller bearings fitted to the shaft.
5) shaft seal for the mechanical seal, by the elasticity and elasticity and seal the pressure of the liquid to achieve the purpose of sealing.
Second, overhaul procedures;
Disassemble the coupling Remove the middle short section - Review and Motor Center - Loosen the volute and bracket bolts - Detach the volute and pump body - Remove the impeller - Remove the sealing cap Disengage the pressure cap - Pull out the mechanical seal sleeve - Remove the seal Lid - Disassemble Couplings - Pull Shaft and Bearing out of Wheel Side - Remove Bearing from Shaft.
Third, maintenance process;
1, multi-stage pump mechanical seal installation;
(1) moving ring assembly; the spring follower ring into the stopper, the ring fitted with a seal ring embedded in the stopper, the seal ring should be coated with a small amount of grease, embedded in the stopper ring , The flange should be assembled closely with the stopper, the assembly of the stopper fitted to the sleeve, measuring the distance, and then locate the screw lock sleeve recess to prevent the release and press Moving ring sealing surface 2-3 times to confirm the dynamic follow-up performance is good.
(2) static ring assembly. Place the washer (sealant ring) in the stationary ring in the correct orientation. Install the stationary ring into the sealing cap after applying the gasket with a small amount of grease on the outer circumference of the gasket and on the sealing cap. In this case, check that the positioning pin position.
(3) mechanical seal assembly. Apply a little grease on the sealing surface of the static and dynamic seal rings and put the sealing cap and static ring together into the main shaft. Pay attention to the "0" ring when installed. When done, check that the pin fits into the groove of the stationary ring and that the stationary ring is beveled in.
2, coupling removal method;
Due to the interference fit of the coupling and the shaft, the coupling must be heated when dismounting the coupling. The heating temperature should not exceed 200 ℃. Demolition of the coupling, the hammer can not be directly struck, but should pad copper rod, and should hit the coupling hub and can not directly hit the outer edge of the coupling, because here easily broken. The ideal solution is to use a dedicated tool.
(4) rolling bearing inspection;
1) Check the drain pump bearing lubricant, dip a little finger oil, first check the status of oil, and then thumb and index finger rub each other to check whether the oil has hard impurities. If there is a description of the bearing to bad.
2) Check the cage is complete, the location is correct, the activities are free. If the cage damage can not be repaired, the new bearings should be replaced.
3) Check the rotation of the rolling bearing. Insert your finger into the hole and rotate the bearing, then let it decelerate and stop gradually. A good bearing should rotate steadily with a slight turning noise, but no vibration. If the bearing is poor, noise and vibration will occur when rotating. Slow down gradually, but suddenly stopped.
4) rolling body and raceway surface can not have spots, holes, dents, peeling, peeling and so on.
(5) Rolling bearing clearance measurement;
Rolling bearing clearance means that if one ring (inner ring or outer ring) is fixed, the other ring has the largest radial or axial maximum amount of movement. Due to the different bearing status, the clearance is divided into the original clearance, with clearance and work clearance. Original clearance refers to the bearing clearance before installation free state; with the clearance is the bearing installed on the shaft and the equipment after the clearance, due to interference with the relationship between the clearance is always less than the original clearance; Work clearance refers to the bearing in the working state of the actual clearance, under normal circumstances, work clearance greater than with the clearance. The clearance measurement method is: Radial clearance can be measured with feeler gauge or rolling under the ball once to measure the thickness; the inner ring can also be fixed with a dial gauge measuring the value of the outer ring (axial and radial to)
Ball, column bearing radial clearance (mm) table
Bearing diameter (Mm) | Radial clearance |
New ball bearings | New column bearing | Limit value |
20 ~ 30 35 ~ 50 55 ~ 80 85 ~ 120 130 ~ 150 | 0.01 ~ 0.02 0.01 ~ 0.02 0.01 ~ 0.02 0.02 to 0.03 0.02 ~ 0.04 | 0.03 ~ 0.05 0.05 ~ 0.07 0.06 ~ 0.08 0.08 ~ 0.10 0.10 ~ 0.12 | 0.1 0.2 0.2 0.3 0.3 |
Can be seen from the table commonly used single row radial ball bearings, radial clearance of 0.01 ~ 0.04mm, while the axial clearance of radial clearance value of 7 to 12 times. Roller bearing clearance than ball bearing clearance big.
Can be seen from the table commonly used single row radial ball bearings, radial clearance of 0.01 ~ 0.04mm, while the axial clearance of radial clearance value of 7 to 12 times. Roller bearing clearance than ball bearing clearance big.
(6) Causes of rolling bearing damage;
Rolling bearing damage in two cases; First, the bearing has reached the end of life and wear and tear scrap; Second, due to poor quality maintenance, improper maintenance, resulting in premature damage. At present, most of the bearing damage is premature damage, the main reason is as follows;
1) poor installation, shaft centerline skew, causing the raceway surface local stress, rapid rolling raceway and rolling body.
2) The assembly of hard particles fall into the bearing, raceway distortion, when rolling through, resulting in raceway crush and metal spalling.
3) Poor lubrication. Including; lack of oil, oil emulsion and so on.
4) bearing inner ring and shaft interference is too small, resulting in inner ring and shaft wear.
5) there is a gap between bearing outer ring and bearing body, causing wear between outer ring and bearing body.
4, fixed shaft head preparation method;
Impeller shaft head cap size of the lock, a direct impact on the stability of pump operation after maintenance, if the cap assembly tightness, the pump running for a period of time reserve cap loose, will cause pump vibration, impeller wear and other accidents, spare cap fastening Excessive force can damage the spindle thread. Therefore, the tight cap must be appropriate when tight, the first molybdenum disulfide coated in a spare cap, with 300? Long sleeve wrench to exert a certain force locking. Lock the lock washer onto the spare cap.
5, prepared cap and shaft biting treatment;
In the spindle assembly disassembly is the occurrence of cap and shaft biting death phenomenon may be due to screw into the debris or thread slight burr, can not take the hard nut rotation method. First of all, should be in the thread with bolt loosening agent, and then use a copper rod to beat the outer edge of the hat, the loosening agent? Into the spindle screw, whipped while rotating spare hat. If you use this method can not solve the problem. You can only choose to destroy the spare hat method, destroy the spare hat has the following two methods;
1) Use the torch to cut the symmetrical position of the spare cap. When cutting the nut, it is required that the spline of the spindle can not be injured.
2) cut with the hat on both sides of the cut open, cutting must be carefully observed at the cutting, different injuries spindle screw. Then use flat 錾 will prepare the hat tick. Check the spindle for damage, if damaged, the screw should be repaired.
6, test center method;
The correct installation of center-specific tools for calibration center work, the required circle less than or equal to 0.04 ?. The face is less than or equal to 0.04 ?. (Except for special requirements).
Bearing diameter
(Mm)
Radial clearance
New ball bearings
New column bearing
Limit value
20 ~ 30
35 ~ 50
55 ~ 80
85 ~ 120
130 ~ 150
0.01 ~ 0.02
0.01 ~ 0.02
0.01 ~ 0.02
0.02 to 0.03
0.02 ~ 0.04
0.03 ~ 0.05
0.05 ~ 0.07
0.06 ~ 0.08
0.08 ~ 0.10
0.10 ~ 0.12
0.1
0.2
0.2
0.3
0.3
