Maintenance
Maintenance refers to checks, inspection and care required to be regularly performed in defined intervals during service life. The maintenance schedule and scope are specified in the operating manual. Maintenance contracts are often provided on a product-related basis.
Regular maintenance of pumps and drives prolongs their service life and saves costs. The related work includes the outside upkeep of pumps and pump sets, maintenance of bearings and shaft seals, as well as like work, e.g. inspection.
Outside upkeep of pumps and pump sets
Pump sets must be cleaned on the outside at regular intervals depending on the degree of contamination. When doing so, the pumps and motors must never be hosed down.
Rusty spots must be removed and treated accordingly, while preservative grease must be applied on exposed parts.
Bearing maintenance
Bearings must be maintained on a regular basis since lubricants use up at different time intervals. Operators need to either replace or top them up (e.g. by changing the oil, refilling the oil, or replacing the grease altogether). The operating manual specifies the intervals as well as lubricants and their quality.
Shaft seal maintenance
Shaft seal maintenance depends on the design variant used. There are gland packings and mechanical seals.
Seals are maintained depending on their design
- It is imperative that gland packings drip slightly during operation. Fully sealing gland packings will cause damage to parts such as the shaft or the shaft protecting sleeve. In this case, the nuts of the gland packing bolts are loosened until the gland packing starts dripping slightly. This also applies to metal, ring and soft plastic packings.
- In most cases, leakage of mechanical seals is not visible from the outside. This means that no special maintenance is required. However, if there are larger amounts of leakage, the sealing elements must be replaced. More details are given in the operating manual.
Other maintenance
To provide additional information, it is recommended to have the operating personnel take part in inspections. In this case, maintenance is often performed following a checklist.
Inspection and maintenance performed by the operating personnel
- Checking the smooth running of the centrifugal pump and drive
- Checking the motor rating taking the power input into account
- Checking the coupling alignment (see shaft coupling)
- Checking the flexible transmission elements for wear (e.g. at coupling disc, coupling bolt and coupling bushes)
- Checking the flushing and barrier water supply systems
- Checking the balancing device if any (e.g. at the balance disc)
- Functional testing of the automatic grease presses (e.g. lubricating oil pump) and grease lines, if any
Example of a checklist
- Checking the smooth running of pump and drive
- Checking the performance data taking the power input into account
- Checking the oil and/or grease lubrication (of the bearings)
- Checking the shaft seals (e.g. gland packing, mechanical seal, lip seals) and, if needed, re-packing the glands, or, in the case of mechanical seals, replacing the rotating and stationary primary rings
- Checking the coupling alignment
- Checking the flexible transmission elements for wear
- Functional checks of shut-off elements and check valves
- Checking the system and its components for corrosion (for example, along the outer surfaces) or for cavitation and erosion damage of internal pump parts
- Determining the spare parts requirements
- Checking the flushing and barrier water supply systems, if any
- Cleaning the solenoid valves, if any
- Checking the balancing devices, if any
- Checking the electro-pneumatic control systems (only for waste water pumps)
- Functional testing of the automatic grease presses and grease lines, if any
- Checking for wear of waste water pumps via the handhole cover, if any
- Measuring the rotor clearance
- Checking the clearances
- Performing a test run after maintenance
