Maintenance of pumps

 Maintenance of pumps:

Lubrication:

To pumps directly coupled on motor shaft it applies that only the bearings of the motor require lubrication.

Pumps designed with bearing bracket and grease lubricated bearings should be lubricated every 3rd month with ball bearing grease (lithium soap grease - MOBILUX EP2 or similar quality). Check that not too much grease is pressed into the bearings as this will cause generation of heat. All bearings are provided with sealing rings in order to prevent humidity and impurities from entering. The grease must not be pressed through these sealing rings. For bearings which are exposed to higher pressures or humidity a heat resisting and water-repelling grease will apply (MOLYPAN LT-1 or similar quality).

For pumps designed with oil lubrication, lubricating oil (MOBILGEAR 682 or similar quality) can be used for normally loaded bearings. For more heavily loaded bearings DTE26 or similar quality should be used. In case of oil sump lubrication the oil level should be checked by means of screw-plug, oil-level glass, oil indicator or other control equipment. see instructions for the pump in question.

3 months' check:

Check the pump for false noises, vibrations and leakage. Pumps with mechanical shaft seal must not leak, neither during standstill with inlet pressure on the pump, nor during operation. The bypass pipe to the mechanical shaft seal must be intact, and permit free flow. Likewise, the piping system and filter of the priming device must be intact and permit free flow. In case of defects they must be corrected immediately as they may greatly influence the operation and life of the pump.

12 months' check:

Disassemble the pump (see instructions). Check the components of the rotary element and perform all necessary repairs. Normal clearance between impeller and sealing rings is 0,2-0,3 mm, and max. clearance is 0,5-0,8 mm, according to size and capacity. Clean the pump casing inside and paint it if necessary (e.g. with APEXIOR No. 3 or with more corrosion-resistant products, e.g. HEMPADUR No. 1513 "Hempel Marine Paints").

Disassembling instructions:

Before starting the disassembly of the pump the sectional drawings of the various pump parts should be studied closely. Most pumps are designed for easy disassembly, and no special tools should be required. The pumps consist of standard components, which means a large number of the components are used in various pump sizes, for which reason it is necessary to keep a small stock of spares for various sizes of the same pump type.

Pumps with split casing, can be disassembled without dismantling motor and pipe connections. After dismounting of coupling bolts (tripartite coupling), bearing housing top part and pump casing top part, the rotating element consisting of shaft with impellers(s), bearings, casing wear rings, mechanical seal(s) and coupling half can be lifted out for inspection, repair or replacement.

Assembling instructions:

When assembling the pump the mechanical seal must be treated with the greatest care. Take care that the various parts are placed correctly. The rubber bellows is mounted on the shaft by means of grease, which gives approx. two hours respite before the bellows jams on the shaft. This means that within this period it can be displaced when the packing flange is clamped by means of two or four nuts. Otherwise, the mechanical seal might be damaged. Before mounting the 0-rings (if any) they must be cleaned and provided with a thin layer of grease. For further information see instructions for mechanical seal.

Bearing packing which was removed, must be reinstalled. In such places where liquid packing has once been used this type of packing must be used again when remounting the pump, as other types of packing would produce wrong spaces.

Mounting of motors on direct-coupled pumps: 

If the pump is delivered without motor a distance ring is mounted between the packing flange and the shaft. This ring must not be removed until the motor has been mounted and the pump shaft screwed together with the motor shaft. Do not forget to remove the ring before starting the pump!

Pumps with split casing:

When mounting the rotating element in the pump, take care that the tongue of the wear rings fits correctly in the groove of the pump casing. The bolts of the pump casing must be tightened with a factor of 6,0 kg/m, the bolts of the bearing housings with a factor of 3,0 kg/m.
When reassembling pumps, take care that impellers, as regards the vanes, have the same direction of rotation as before the disassembling.

Maintenance (Storage instructions): 

General instructions:
All pumps which are taken out of operation for some time should be protected against corrosion and frost by being kept in a dry place. Additionally, the following directions should be observed:

Preservation of bearings:
Both ball / roller bearings and slide bearings should be lubricated all over with their normal lubricant.

Preservation of interior parts of the pumps: The interior parts of the pumps should be protected against aggressive pumping media, for instance by using a water-repelling solvent containing at the same time corrosion inhibiting nitrides. We recommend MOBIL OIL - ARMA 245 or similar quality.

Preservation of gear wheel pumps and gearboxes: Gear wheel pumps do not need any protection if they have been operating with oil products. If not, they should be lubricated all over with a neutral oil. Gearboxes should be completely filled with the oil specified. If the standstill lasts longer than 12 months the oil should be emptied and replaced by MOBILARMA25 or similar quality and the gearbox should be flushed with this oil.

Preservation procedure: 

Flush the pump with pure, hot water (does not apply to screw pumps and gear pumps) and let it airdry. Close the valves on both sides of the pump and flush the pump with MOBIL ARMA 25 or similar quality. Flushing can take place through the manometer connections.

Restarting of the pumps: 

When restarting pumps it is advisable to fill the pump with hot water through the manometer connections (does not apply to screw pumps and gear wheel pumps) and to turn the pump shaft by hand before starting the pump. Watch the operation of the pump for about 10 minutes and open the valve in the normal way. Bearings, gearboxes etc. should be lubricated with normal oil or grease if a change of oil has taken place.