How to install the rotor of horizontal multistage pump for mine?

Centering method of multistage pump rotor assembly

In the process of water pump assembly, there are many assembly processes. This paper briefly introduces the method of rotor alignment in the assembly process of multistage pump;

A very important problem in assembly is to check whether the impeller outlet center and the guide vane (guide vane) inlet center are the same, that is, each impeller outlet center must be aligned with the guide vane inlet center. The adjustment of "consistent center" can not only ensure the normal working efficiency of the pump, but also avoid the harm of fixed impeller or front and rear wear.

The "uniform center" is mainly determined by the position of the balance plate. During the operation of the pump, the balance disc moves back and forth, which directly affects the consistency between the outlet center of the impeller and the inlet of the guide vane. Because the balance plate works, it is balanced and environmentally friendly, and automatically balances the axial force in a small gap (usually 0.1-0.25mm). Therefore, when the balance plate approaches the balance ring, check and adjust the "uniform center".

The condition of "consistent center" is: lock the rotor lock nut 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. When working, the gap between the balance plate and the balance ring is only about 0. 1mm, which can also be considered as centering. There are several alignment methods:

First kind

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

2. Install the main impeller and impeller fixing sleeve, so that the impeller is 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, so as to finally check the alignment of the impeller and the guide wing. When the outlet center of the main impeller is aligned with the guide wing, it should be noted that the impeller should be close to the front shaft sleeve. At this time, the impeller cannot be close to the suction housing.

3. After the middle section is covered with a layer of green paper pad, install the middle section and the secondary impeller. Then install the impeller fixing sleeve, the middle section and the third-stage impeller to the pump casing in turn, install the pump body bolts and nuts, and tighten the nuts.

4. Install the balance plate and lock the balance plate with the shaft sleeve and the shaft sleeve lock nut. Press the balance plate on the balance ring and check the mark on the front end of the pump shaft. If the mark position remains unchanged, it means that the outlet center of the first stage impeller is aligned with the inlet center of the first stage guide vane. Because the distance between the impeller and the guide vane has been measured and adjusted to be 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.

second kind

Check and adjust the axial displacement of the rotor. When the outlet of the impeller is consistent with the center of the inlet of the guide vane, there is a proper gap on both sides of the impeller. Before installing the balance plate, the range of motion on both sides of the impeller is called the axial displacement of the rotor. After installing the balance plate, when the balance plate is close to the balance ring, the rotor cannot move in the suction direction, but only in the discharge direction. Therefore, check the axial displacement of the rotor after installing the balance plate. If it is equal to the specified value, it means that the alignment is good; If it is less than the specified value, it means that the impeller is biased towards the discharge end; If it is greater than the specified value, it means that the impeller is biased towards the suction end.

The third category

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

2. Install the main impeller and impeller fixing sleeve, so that the impeller is close to the front shaft sleeve.

3. After the middle section is covered with a layer of green paper pad, install the middle section and the secondary impeller. Then install the impeller fixing sleeve, the middle section and the third-stage impeller in turn until the pump casing, install the pump body bolts and nuts, and tighten the nuts symmetrically. Install a special fixed sleeve with a length greater than the sum of the hub length and total displacement of the balance disc, install the shaft sleeve and lock it with a lock nut.

4. Push the rotor forward to the limit position, then mark the pump shaft according to the end face of the front packing gland, then pull the rotor back to the limit position, and then mark the reference shaft to measure the total displacement.

5. After removing the fixed sleeve, install the balance plate and lock it. Place the balance plate near the balance ring and mark the shaft. Then pull the rotor back to the end point and mark it on the shaft. Measure the distance between two marks. If it is equal to half of the total displacement, the outlet center of the impeller is the same as the inlet center of the guide vane. Otherwise, the thickness of the gasket between the balance disc hub and the last stage impeller hub should be adjusted to meet the requirements.