Section III trouble-free pumping

The given pumping is shown in fig. 8

Fig. 8

1. Shaft – shaft overhang is kept as short as possible, virtually eliminating shaft deflection. This results in low vibration, longer seal and bearing lifetime and silent operation.

2. Cooling system – in pumps rated below 9 kW, cooling is achieved through fins on the stator casing. In larger models, cooling water flows around the stator housing, inside a cooling chamber.

3. Motor – squirrel cage induction motor, specially designed and manufactured by IIT Flygt for use in submersible pumps. Stator windings insulated to Class F rated at 155°C (310°F) allow for up to 15 starts per hour. Heat-shrink fitted, the stator is locked against rotation, for perfect alignment with rotor, without the need for external locking bolts that can lead to leakage.

4. Lifting device – large lifting handle with correct geometry for easy and secure handling.

5. Cable entry – separate sealing and strain-relief functions reduce the risk of damage being caused by careless handling.

6. Bearings – The bearing arrangement has been designed by ITT Flygt for operation on a vertical shaft. The upper bearing, counteracting radial forces, is of the roller or ball type. The lower bearing is a double angular-contact ball bearing that is designed to take both radial and axial forces.

7. Oil housing – in addition to lubricating the seals, the oil-filled compartment carries heat away from the bearings. The housing also provides additional security against liquid penetration. Oil checks are easy to perform and help determine the condition of the seals.

8. The oil housing is now filled with new white, environmental oil that, free from aromatic hydrocarbons, is medically clean and is even approved by the FDA for use in the food industry.

9. Seals – two sets of mechanical shaft seals work independently for double security. The seals are balanced, which means that when external pressure increases, the surface pressure on the seal rings also increases. Outer seal mating rings are made from tungsten carbide and on the smaller models either tungsten carbide or ceramics. For more aggressive media, corrosion-resistant seal materials are available.

SECTION IV

TESTING

Control your knowledge of the basic principles of mechanics

Test to section I

1. What is mechanics (a science, a branch of industry, a branch of engineering)?

2. What sections does mechanics consist of?

3. What is its aim in technology?

4. In what fields of engineering is mechanics applied?

5. How is it connected with the adjacent (смежный) sciences?

6. When and where were the basis of mechanics born?

7. What is Newton’s role in mechanics?

8. What are the basic concepts of mechanics?

9. Name foreign scientists associated with mechanics.

10. Who were Russian scientists and inventors dealing with mechanics?