Module 5. Plant maintenance

Lesson 10

10.1 Introduction

The spare part programme is an important tasks to upkeep the all machineries for production. Most of the dairy plant purchase various equipment from different supplier. As a result, there is often practically no uniform standard of equipments in dairy plant. Therefore it is necessary to keep various types of spares and supplies to upkeep the machineries for smooth running of operations. So store should contain consumable items such as gaskets, standard lubricants and paints and three basic groups of engineering accessories:
  • Equipment spare parts.
  • Complete components.
  • Pipes and fittings, bolts, nuts and washers, bars and plates of different metals, electric components and other general types of engineering accessories.
The total number of items stored often amounts to thousands, of which a negligible part or sometimes even the majority may be imported .The selection of spare parts kept in the store is based on the manufacturers' recommendations and on the plants own experience of local operating conditions. The quantities to be kept should ensure regular and trouble-free plant performance without overstocking the stores.

In the spare parts lists there are items which are on relatively steady demand such as rubber gaskets for milk pipes, plate gaskets for heat exchangers, graphite and rubber sealing for pumps, electric relays and special bulbs, selected bearings, springs and automatic switches, etc. Also some consumable items such as automatic recorder charts and inks, special lubrication components and even packaging materials to which packaging machines are particularly sensitive, such as aluminum capping foils for bottling.

It is much more difficult to decide on items which are used sporadically. The demand for them is erratic and only experience can tell what deserves to be stored in the plant. This could involve parts of machines which theoretically last for the lifetime of the machine, such as shafts carrying spray discs in milk driers, plates in heat exchangers and pressure and temperature indicators. There are instances when they need quick replacement and should be available in the store.

10.2 Lubrication System

Lack of lubrication is one of the principal causes of equipment breakdown. The best solution is to have a regular lubrication schedule, and perhaps a lubrication chart for each machine, setting the frequency of lubrication, type of lubrication needed, and places to be lubricated.

Modern equipment calls for certain types of lubricants for certain types of bearings e.g. light, high speed bearing will require a light oil, whereas a heavy duty, low speed bearing will require heavier oil.

Bearings that are operated at high temperatures must have a lubricant specially adapted for this use, just as those bearings that operate at extremely low temperatures will require zero oil.

Many dairy plants have rather high humidity and for that reason the moisture problem should be considered. Certain lubricants are available that resist rusting and corrosion due to moisture. There are also oils that resist emulsification with water and are advantageous for flooded systems of lubrication where gears and chains run in oil.

The most tightly enclosed oiling system will with time allow moisture to accumulate. It is essential to occasionally check the oil in an enclosed drive to make certain it is not contaminated with water. Usually the water will collect at the bottom and may be drawn off easily.

10.3 Benefits of Lubrication

The benefits of proper and timely lubrication can be summarized as:
  • Less production downtime (because fewer breakdowns) with all its related in-plant savings and customers' benefits.
  • Fewer major overhauls, hence less costly repair bills.
  • Fewer repetitive repairs.
  • Less spoilage and product waste, hence a factor in better quality control.
  • Postponement or elimination of cash outlays for premature replacement of physical plant and/or equipment/ because of better conservation of assets and increased life expectancy.
  • Requirement of less standby equipment thus reducing capital investment.
  • Shift from inefficient “breakdown” maintenance to less costly scheduled maintenance/ hence better work control and saving due to
  • Less plant outage and reduced maintenance costs.
  • Better spare parts control, leading to minimum inventory yet having appropriate spares at hand when needed.
  • Greater safety for workers and improved protection for plant.
  • Reduced utility and fuel costs.
  • Lower unit costs of manufacture.
  • Greater certainty in meeting production schedules.
These are all realistic benefits that apply in any industrial economy, including dairy and food industries. To sum up, the benefits of lubrication are the same as those accruing to any well manage and well maintained plant, besides the economies it provides in greater plant efficiency, reduced maintenance costs and lower overall manufacturing costs.

Last modified: Friday, 5 October 2012, 6:25 AM