A brief discussion on the alignment method of roto

2022-08-16
  • Detail

A brief discussion on the centering method of rotor assembly during the assembly of multi-stage pump

a very important problem in the assembly is to check whether the impeller outlet center is consistent with the guide vane (deflector) inlet center, that is, the outlet center of each impeller must be aligned with the guide vane inlet center. Adjusting the center uniformly not only ensures the normal efficiency of the pump, but also avoids the hazards of immobility, or the front and back rubbing of the impeller

the consistency of the center is mainly determined by the position of the balance plate. During the operation of the pump, the balance plate moves back and forth, which directly affects the consistency of the center of the impeller outlet and the guide vane inlet. When the balance plate works, it moves within a small gap (usually 0..25 mm) with the balance environmental protection, automatically balancing the axial force. Therefore, the inspection and adjustment center can be carried out when the balance disc is close to the balance ring

the condition of consistent center is: lock the locknut of the rotor and tighten the tension bolt on the pump body. When the balance disc is close to the balance ring, the outlet center of the impeller is aligned with the inlet center of the guide vane. During operation, the clearance between the balance disc and the balance ring is only about 0.1mm, so it can also be considered as centering. In the future, there are the following methods:

the first one is

1. Thread the shaft with the shaft sleeve and key at the suction end into the suction shell

2. Install the first stage impeller and impeller retaining sleeve, and make the impeller close to the front shaft sleeve. Then move the pump shaft so that the outlet center of the first stage impeller is consistent with the inlet center of the first stage guide vane. At this time, make a mark on the shaft at the front end of the pump shaft relative to the end face of the packing gland to facilitate the final inspection of the alignment of the impeller and the guide wing. It should be noted that when the outlet center of the first stage impeller is adjusted to align with the guide wing, the impeller should be close to the front shaft sleeve. At this time, the impeller cannot be close to the suction housing

3. After laying a layer of green shell paper pad on the middle section, install the middle section and the second stage impeller. Then, install the impeller retaining sleeve, the middle section, the third stage impeller, and even the pump housing in turn, install the pump body bolts and nuts, and tighten the nuts

4. Install the balance disc, and lock the balance disc with the shaft sleeve and the shaft sleeve lock nut

stick the balance disc close to the balance ring and check the mark on the front end of the pump shaft. If the position of the mark does not change, it means that the outlet center of the first stage impeller is aligned with the inlet center of the first stage guide vane. Since the impeller spacing and guide vane spacing have been measured and adjusted to make them equal before assembly, the impellers at all levels are aligned with the corresponding guide vanes respectively. If the position of the mark changes, it means that the thickness of the gasket between the balance disc hub and the last stage impeller hub is not appropriate. As long as the thickness of the gasket is adjusted, the problem can be solved

the second kind of

uses the method of checking the axial displacement of the rotor to check and adjust. Under the condition that the impeller outlet is consistent with the guide wing inlet center, the new material industry is a strategic and basic industry, and there is appropriate clearance on both sides of the impeller. The range of activity on both sides of the impeller before installing the balance disc is called the axial displacement of the rotor. After installing the balance disc, when the balance disc is close to the balance ring, the rotor cannot move in the suction direction, but only in the discharge direction. Therefore, after installing the balance disc, check the axial displacement of the rotor. If it is equal to the specified value, it means that the alignment is good with a level ruler; If it is less than the specified value, it indicates that the impeller is biased towards the discharge end; If it is greater than the specified value, it indicates that the impeller is biased towards the suction end

the third kind

1. Put the shaft with the shaft sleeve and key at the suction end into the suction housing

2. Install the first stage impeller and impeller retaining sleeve, and make the impeller close to the front shaft sleeve

3. After laying a layer of green shell paper pad on the middle section, install the middle section and the second stage impeller. Then, install the impeller retaining sleeve, the middle section, the third stage impeller, and even the pump housing in turn, install the pump body bolts and nuts, and tighten the nuts symmetrically. Install a special retaining sleeve with a length greater than the sum of the balance disc hub length and the total displacement, install the shaft sleeve, and lock it with a lock nut

4. Push the rotor to move it to the front extreme, and then take the front packing gland end face as the reference, make a mark on the pump shaft, pull the rotor to move it to the rear extreme, and then make a mark on the shaft at the reference to measure the total displacement

5. After removing the gear sleeve, install the balance disc and lock it. Make the balance disc close to the balance ring and make a mark on the shaft. Then pull the rotor backward to the end point and make a mark on the shaft. Measure the distance between the two marks. If it is equal to half of the total channeling, the impeller outlet center is consistent with the guide vane inlet center. Otherwise, it is necessary to adjust the thickness of the gasket between the balance disc hub and the final stage impeller hub to meet the requirements

for multi-stage pumps with ball bearings at both ends, since the inner ring of the bearing is fixed on the shaft and the outer ring is supported on the bearing frame, the axial movement of the whole rotor slides in the bearing seat by the outer ring of the bearing. Therefore:

1. When dismantling the multi-stage pump without positioning shoulder on the shaft, the existing change experiment can only record semi quantitative indicators such as the number of twisted turns, the position of the front axle sleeve must be marked to facilitate the restoration of the original assembly

2. There should be a clearance between the boss of the bearing gland and the outer race of the rolling bearing along the axial direction

allen bradley 1756 ir6i
1756 cnbr
ab 1769 ecr
1756 mo2ae

Copyright © 2011 JIN SHI