What should be paid attention to when repairing multistage centrifugal pumps?

If the condition of the multi-stage pump is over, it is best to look at the manufacturer's maintenance manual and the general assembly drawing to see what special places need attention.

   First, when disintegrating:

   1. Before the thrust bearing is removed, the balance plate should be measured by the dial gauge, and the record should be made;

   2. When the multi-stage pump is disassembled, the parts must be marked according to the original assembly order, so as to avoid confusion and misplacement when loading.

   3. Small pieces (such as keys) that are inconvenient to be marked can be placed together with the impeller or vane (middle section) of the same class.

   4. When disassembling, you can intuitively feel if there are abnormal parts, such as loose fitting.

   Second, parts maintenance:

   1. Visually check whether the surface of each part is normal. Each mating surface must be scratch-free, rust-free, etc.

   2. Whether the tolerance of the critical matching part of the measuring tool is qualified;

   3. Whether the clearance of the impeller seal ring, the casing seal ring, the vane seal ring, the interstage bushing, etc. is within the tolerance range, and the wear is too large and needs to be replaced;

   4. Check if the bearing is in good condition;

   5. All seals and gaskets are preferably replaced with new ones;

   Third, back loading:

   1. Install the rotor first and re-run the dynamic balance test;

   2. Reload the parts in the reverse order of the pump removal. Pay attention to the amount of clearance at each seal ring when reloading, to ensure that there is no error;

   3. The total number of rotors should be measured before the balance plate is installed;

   4. After installing the balance plate, measure the rotor half string.

   5. Correspond to the total string quantity and half string quantity required on the general assembly drawing of the manufacturer, it should basically meet the drawing requirements. In general, the half string amount is about half of the total string amount.

   6. Evenly tighten the main bolts, pay attention to the angle;

   7. A piece of dial gauge is sucked on the shaft, and the rotating shaft is used to mark the balance plate. The tolerance is not required to exceed 0.06 according to the requirements of the drawings;

   8. When installing the thrust bearing, pay attention to adjust the clearance of the balance disc. The balance disc clearance should be adjusted to the drawing requirements by using the adjusting ring in front of the bearing.