Pump installation with proper methodology is an important activity. Improper pump installation could lead to vibration issues during pump operation. In this article, we will explore a few of the pump installation best practices or pump installation checklist to reduce vibration problems.
For proper functioning of the centrifugal pumps in any plant, the following points need to be taken care of while installing.
Checking the site before installation
- Make sure the foundation concrete is of sufficient strength.
- Only place the pump set on a foundation whose concrete has set firmly.
- Only place the pump set on a horizontal and level surface.
- Refer to the weights given in the Pump general arrangement (GA) drawing.
- All structural work required must have been prepared in accordance with the dimensions stated in the outline drawing/general arrangement drawing.
Improper installation in potentially explosive atmospheres
- Comply with the applicable local explosion protection regulations.
- Observe the information in the datasheet and on the nameplates of the pump and motor.
Installing the pump assembly
Always install the pump set in a horizontal position to ensure proper self-venting of the pump. Refer Fig. 1:
- Position the pump on the foundation and use a spirit level to align the shaft and discharge nozzle. Permissible deviation: 0.2 mm/m.
- If required, use shims (2) to adjust the height. Fit shims between the baseplate/foundation frame and the foundation itself; always insert them to the left and right of the foundation bolts and in close proximity to these bolts.
- For a bolt-to-bolt clearance > 800 mm, insert additional shims halfway between the adjoining holes. All shims must lie perfectly flush.
- Insert the foundation bolts (4) into the holes provided.
- Use concrete to set the foundation bolts (4) into the foundation.
- Wait until the concrete has set firmly and then align the baseplate.
- Tighten the foundation bolts (4) evenly and firmly.
- Grout the baseplate using low-shrinkage concrete with standard particle size and a water/concrete ratio of ≤ 0.5.
- Produce flow-ability with the help of a solvent.
- For low-noise operation, the pump set can be mounted on vibration dampers upon confirmation by the manufacturer. In this case, only fasten the flexible elements at the baseplate after the piping has been connected.
- Expansion joints can be fitted between the pump and the suction/discharge line.
- Observe the permissible forces and moments at the pump nozzles.
- Take appropriate measures to compensate for the thermal expansion of the piping.
- The suction lift line/suction headline has been laid with a rising/downward slope towards the pump.
- The nominal diameters of the pipelines are at least equal to the nominal diameters of the pump nozzles.
- To prevent excessive pressure losses, adapters to larger diameters have a diffuser angle of approximately 8°.
- Thoroughly clean, flush and blow through all vessels, pipelines, and connections (especially of new installations).
- Before installing the pump in the piping, remove the flange covers on the suction and discharge nozzles of the pump.
- Use a filter with laid-in wire mesh (mesh width 0.5 mm, wire diameter 0.25 mm) of corrosion-resistant material. Use a filter three times the diameter of the piping. Conical filters have proved suitable.
- The volute casing and casing/discharge cover take on the same temperature as the fluid handled.
- Make sure the space between the casing cover/discharge cover and the bearing cover is sufficiently vented.
- Never close or cover the perforation of the bearing bracket guards.
- Never insulate the casing cover and the bearing bracket.
- Make sure that the coupling is correctly aligned at all times.
- Always check the coupling after the pump has been installed and connected to the piping.
- Also, check the coupling of pump sets supplied with pump and motor mounted on the same baseplate. Refer Fig. 2.
- Mark the installation position of the coupling by dotting marks (balancing condition).
- Remove the coupling spacer.
- While the pump’s coupling is disengaged, also check the direction of rotation.
- Check the alignment of the coupling halves with a dial gauge (see Fig. 2). Admissible run-out of coupling face (axial) maximum 0.1 mm. Admissible radial deviation, measured over the complete circumference, maximum 0.2 mm.
- After having installed the pump set and connected the piping, check the coupling alignment and, if required, re-align the pump set (with the motor). Any differences in shaft centre height between the pump and the motor are compensated by means of shims.
- Check the coupling alignment.
- Unscrew the hexagon head bolts at the motor.
- Insert shims underneath the motor feet until the difference in shaft centre height has been compensated. Refer Fig. 3.
- Re-tighten the hexagon head bolts.
- Check that the coupling and shaft can easily be rotated by hand.
- Always operate the pump set with a coupling guard. If the customer specifically requests not to include a coupling guard in Vendor’s delivery, then the operator must supply one! Observe all relevant regulations for selecting a coupling guard.
- Reinstall the coupling guard and step guard, if any.
- Check the distance between coupling and coupling guard. The coupling guard must not touch the coupling.
- Check the available mains voltage against the data on the motor nameplate.
- Select an appropriate start-up method.
- Change the motor’s direction of rotation to match that of the pump.
- Observe the manufacturer’s product literature supplied with the motor. Never check the direction of rotation by starting up the unfilled pump set. Separate the pump from the motor to check the direction of rotation.
- Never insert your hands or any other objects into the pump. Check that the inside of the pump is free from any foreign objects.
- The correct direction of rotation of the motor and pump is in the clockwise direction (seen from the motor end). If the direction of rotation is incorrect, check the connection of the motor and the switchgear, if any.
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