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Assembly process of centrifugal pump

1. Cleaning: The parts must be inspected and qualified, the material code meets the requirements of the drawings, the surface is cleaned, and the surface is coated with engine oil. The inside of the bearing box is cleaned and coated with oil-resistant enamel, and allowed to dry naturally for 24 hours. After passing the inspection, it can be assembled.

2. Assembly of bearing and shaft:
The bearing is heated to 90℃-110℃ in a heating furnace and then cooled on the shaft. First install the bearing gland on the left side of the bearing box, then put the bearing and shaft assembly into the bearing box, leaning on the left bearing gland, and measure the size of the drive end bearing gland and the end face of the bearing outer ring. The CZ pump is at 0.30 -0.70mm, the gap of ZA pump is 0-0.42mm. If ZA pump bearings are used in pairs, install and use shrink nuts to lock the bearings to the outer rings of the two bearings, which can rotate relatively slightly to obtain an ideal clearance.

3. Assembly of mouth ring, impeller and pump body
When assembling the mouth ring with the impeller and pump body, pay attention to evenly install the mouth ring around the impeller or pump body to minimize the shape error of the mouth ring. After installing the set screws or welding, measure the radial runout of the impeller, the mouth ring and the gap between the two. The measured value should meet the general technical conditions of pump assembly, and the out-of-tolerance parts should be trimmed.

4. Sealed installation
4.1   cartridge type mechanical seal installation
When installing the cartridge mechanical seal, first install the seal on the pump cover with double-ended studs and nuts. After the pump shaft penetrates into the seal sleeve and the bearing housing is connected to the pump body, stop the seal The gasket is moved away from the bushing.
In order to reduce the wear of the O-ring during installation, the parts that the O-ring passes through can be lubricated, but the ethylene-propylene rubber ring should be lubricated with soap or water.
4.2  Packing seal installation
Before installing the packing seal, determine the length of each circle according to the outer diameter of the shaft sleeve. After a little flattening, wrap it around the sleeve and push it into the stuffing box. If there is a water seal ring, install it as required. After the packing is installed, press it evenly with a packing gland.
Stainless steel centrifugal pump

5. Install the impeller
For single-stage pumps, the impeller should be statically balanced and meet the technical requirements. After installing the impeller on the shaft and tightening the nut, put the entire rotor into the pump body and tighten it with the nut.
For multi-stage pumps, in addition to the static balance test for the impeller, a trial installation of the rotor components is required. Each impeller and the shaft are assembled together, marked, and a dynamic balance test is performed. The test results should meet the technical requirements.
When installing, push the balance drum, shaft sleeve and all the impellers to the right until the first stage impeller and shaft sleeve lie on the shaft shoulder respectively, and measure the gap between the shaft sleeve and the balance drum to make it ≥0.5. If the gap is too small, trim the balance drum , Make the gap meet the requirements. Then install the shaft with the first stage impeller into the inlet housing, and install the impeller and the middle section shell with guide vanes onto the shaft until the outlet section. Fix the pump components with the screw, install the balance device, seal and Bearing parts, determine the correct middle position of the rotor, adjust the axial clearance of the tapered bearing to 0.04-0.06mm.

6. Adjustment of bearing box of horizontal multi-stage stainless steel centrifugal pump
The bearing housing of the non-stop positioning of the multi-stage pump should be adjusted during installation. Rotate the adjusting bolt to make the bearing box move vertically and horizontally, measure the limit positions of the bearing box in two directions respectively, take the average value, and finally lock it with a lock nut. Hit the positioning pin, and then install the seal and bearing. The rotor axial adjustment is medium.

7. Coupling installation (the pump head has been fixed)
Installation of membrane coupling:
Install the pump end and motor end couplings of the coupling on the corresponding shafts, and use a dial indicator to correct the coaxiality of the two shafts (adjust the position of the motor with a gasket in the vertical direction) to make the diameter between the two shafts The direction jump is ≤0.1, the end jump is ≤0.05, after reaching the requirements, install the middle connection part. When the speed is >3600 rpm, the radial runout is ≤0.05, and the end runout is ≤0.03. If the operating temperature is relatively high (approximately greater than 130°C), the final calibration should be performed under the high temperature conditions when the pump is running.
Installation of claw coupling:
Similar to the membrane coupling, the two flanges of the coupling are respectively mounted on the corresponding shaft, and the mutual position is adjusted with a ruler. If the rotation speed is greater than or equal to 3600 rpm, the alignment method of the membrane coupling should be used for alignment.

8. Paint
Painting should be carried out in a clean and dry place. The ambient temperature should not be lower than 5℃, and the relative humidity should not be greater than 70%. If the relative humidity is greater than 70%, the paint should be added with a proper amount of moisture-proofing agent to prevent the coating from whitening.
Non-steel metal parts, stainless steel parts, chrome-plated, nickel, cadmium, silver, tin and other parts: sliding parts, matching parts, sealing surfaces, rib surfaces, signs and steering plates are not painted.


Post time: Dec-22-2022