Maintenance; Checking And Changing The Oil In The Mechanical Seal Chamber; Checking Parts Subject To Wear; Main Components Of The Sbn And Smn Pumps - Zenit MAI 100/4/80 A0CM-E Manuel D'utilisation Et D'entretien

5. MAINTENANCE

Before inspection and maintenance operations carefully read and apply the safety procedures indicated in paragraphs 1.2 and 1.3
WARNING: the explosion proof layer and cable clamps of any explosion proof motor pump must not be interfered with.
To ensure regular and long-lasting operation of the motor pump the user must perform regular inspections, periodic maintenance and replacement
of used parts. Monthly inspections are recommended, or every 500-600 working hours.
- check that the supply voltage corresponds to the values indicated on the data plate;
- check that noise and vibrations are at their original levels;
- for three phase motors, use amperimetric pincers to check the absorbances on the three phases are balanced and do not exceed the values
shown on the rating plate.
An exploded view of the motor pump is shown in fig. 2-2/a-2/b-2/c

5.1 CHECKING AND CHANGING THE OIL IN THE MECHANICAL SEAL CHAMBER

Before inspection and maintenance operations carefully read and apply the safety procedures indicated in paragraphs 1.2 and 1.3
The oil should be changed every 5000-7000 working hours, or at least once a year.
Proceed as follows:
Position the motor pump horizontally.
- Unscrew the plug and drain off the oil into a suitable container, or use an oil aspiration device.
- If the oil is clean, then the mechanical seal is still in good condition and the chamber can be refilled with fresh oil.
- If a very small quantity of water is detected at the bottom of the mechanical seal chamber, this will be due to condensation and is normal, not a
sign of any fault with the mechanical seal.
- If a substantial quantity of water has entered the oil chamber and contaminated the oil, this indicates that the mechanical seal needs inspecting,
and perhaps replacing
- Fill the oil chamber completely with biodegradable oil such as CASTROL HYDROIL P 46 or a similar oil. When it is full, remove 8% of the total
amount of oil to allow formation of an adequate air cushion in the chamber.
- When finished tighten the plug and re-install the motor pump.
If none of the above is available, exceptionally, common vaseline oil can be used. For maintenance, contact our nearest service centre.
Any repairs to the motor pump must be carried out by the manufacturer or by specialist personnel. If this is not respected, the guarantee will be
invalidated and the machine may become unsafe.

5.2 CHECKING PARTS SUBJECT TO WEAR

Before inspection and maintenance operations carefully read and apply the safety procedures indicated in paragraphs 1.2 and 1.3
During programmed maintenance or at any time in which the performance of the motor pump should be reduced or if vibrations and noise
should increase, the hydraulic parts subject to wear must be checked. Original spare parts only should be used. If the hydraulic part should
be partially or totally blocked it should be cleaned thoroughly with a jet of high pressure water. If necessary dismantle the hydraulic part
referring to the exploded view in fig. 2-2/a-2/b-2/c
To restore the hydraulic characteristics of the motor pump use the appropriate hexagonal spanner on the grub screws inside the inlet hole which
regulate the distance between the impeller and the shimming plate, which must be between 0.3 and 0.5 mm (MAI).

5.3 MAIN COMPONENTS OF THE SBN AND SMN PUMPS

5.3.1 COOLING JACKET

The cooling jacket is assembled by inserting the jacket into the casing up until the intermediate support is reached. The lower ring is then placed on
the top, then the two O-rings are housed and, lastly, the upper ring is tightened onto the first, pressing the two sealing elements against each other.
Dismantling of the upper ring is facilitated by two spot-faced and threaded holes into which two screws will be tightened.

5.3.2 LOWER SUPPORT BEARINGS

The oblique ball bearings must be mounted in an X-shaped configuration. To do so, the first bearing should be inserted with the widest band of the
ring turned downwards, and then the second bearing inserted with the flat band turned upwards. The radial grooves on the lower support must first
have been filled with grease. Before each rolling unit is inserted, the rolling races must also have been suitably filled with grease.
The first ring nut for axially blocking the pair of bearings is tightened by means of three dowels to be fixed in place using Loctite; no adjustment is
needed.
The entire operation ends by mounting the closing flange, which will also have been filled with grease. Again in this case, no adjustment is required;
simply make sure that there is a bit of play between the flange and the lower support, as well as between the first ring nut and the flange.
Dismantling of the flange is facilitated by the two "thumb-nails" on the lower support which aid the use of levers.

5.3.3 MECHANICAL SEALS

The assembly of the first mechanical seal ends with the insertion of a second ring nut identical to the first (bearings), without any adjustment.
The second mechanical seal requires closing by means of a bushing, available in two configurations, N (for tandem seals) and T (for opposed
seals).
A pin wrench is required in order to assemble and dismantle the ring nut.

5.3.4 TIGHTENING THE IMPELLER

The impeller is keyed onto the shaft by means of conical coupling. The assembly of the impeller does not require axial adjustments, but the closing
of the M20 lead screws does require tightening with 260 Nm.
Dismantling takes place by removing the lead screw; the impeller is then removed by screwing an M24 screw into the hole (extractor). In order to
avoid damage to the thread on the head of the shaft, insert a spacer into the threaded hole.

5.3.5 PUMP BODY

Dismantling of the pump body can be carried out by using a number of screws in threaded holes of the intermediate support to be used as
extractors; dismantling of the suction flange takes place in the same way.
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