The mobile servicing unit should have sufficient capacity to store all the POL that may be required by the field equipment, together with pumps and Helios of required length. The unit is also equipped with a small air compressor and water tank. A number of individual servicing operations are undertaken simultaneously so that time spent on completing the job is reduced to a minimum. The strength of the servicing team depends on the number of these simultaneous operations. The mobile unit should be split up into at least two parts - one for fuels and lubricants and the other for treys and tubes.
The central servicing depot is also adequately equipped with similar equipment and crew as provided in the mobile unit. The storage of fuels and lubricants at the depot is done to ensure cleanliness and avoid contamination with dust, leakage and evaporation. For fuel oil two or more tanks of adequate capacity are provided, so that while filling from one tank is taking place, sedimentation takes place in the other tariffs. Before supply from a tank is drawn, a period of 3-4 days should be allowed for sedimentation. The storage tanks may be placed underground or overground. In the underground arrangement a manhole, filling and breather connections and a pump connection are provided on the top of the tank. While, in the overground arrangement a drain plug for water and drain tap for removing sediment are provided at the bottom of the tank. From the large storage tanks fuel is transferred through the pump to smaller tanks placed overhead. Fuel to the equipment tank is fed from these overhead tanks through filters and metering pump, thus ensuring supply of metered quantity of clean fuel. It is necessary to clean all tools, pipes and caps before dispensing fuel to the machine. Cleanliness is the most important factor in storage and handling of oils and lubricants.
Proper lubrication of machines is an important aspect of servicing. The right type of lubricant should be applied at the right place, at the right time and in right quantity. The recommendations of the manufacturers as given in the lubrication charts and schedules are the best guides. Suitable lubricants should be procured aid stored properly. It is preferable to have the minimum number of brands arid grades of lubricants to avoid errors in their use. It is a good practice to paint the grease nipples and the oil caps to correspond with the colour scheme on various grease and oil containers. A responsible person under the overall charge of a competent lubrication engineer should supervise the dispensing of the lubricants.
Supplying of cooling water is another item of dispensing during servicing. Soft and clean water should be used. If water quality is unsuitable, addition of a small amount of suitable oil may reduce the formation of scales and deposits. The crew should check and make adjustments, wherever necessary, of the entire cooling system - fan belt, pump, pump seals, radiator and other parts. Coolants should be used where recommended. These prevent rusting of the steel parts of the radiator, and thus increase the life of those
components.
Another major item of maintenance is servicing of wheels and tracks. Care of tyres includes ensuring correct inflation pressure and maintaining haul surface in top condition. The servicing team should ensure that the right type pressure is maintained and when the equipment is to stand idle for long periods, it is properly jacked up. Contact with grease or oil should be avoided. In track machines, proper adjustment of track, greasing of the rollers, idler and sprocket are important aspects of servicing. Any bolts and nuts found loose should be tightened. Other items to be attended include electrical parts, wire ropes and cutting blades, power control units, clutch and transmission. It is desirable to divide the maintenance personnel into specialized teams each attending to one particular mechanism of the machine.
Tightening of any loose bolts and nuts found during servicing is an essential part of the servicing crew's duties. The crew should have suitable repair hand tools, such as hammer, screw drivers, wrenches, pliers, and so on. The clutch and brake adjustments on equipment which contain hoisting gear like cranes, drag lines, pile drivers, etc. need special attention. Loose chains and belt drives, etc. should be tightened. The maintenance supervisor should prepare a check list of the various parts and devices to be checked by the servicing crew during servicing so that a thorough and systematic check of the important systems of the machine is carried out by the crew. The extent of these checks and adjustments should be judiciously decided upon by the supervisor. Repairs that need extensive work in a field workshop should not be done by the servicing team. Repairs to dust sensitive equipment (such as fuel pumps, injectors, etc.) should be undertaken in the workshop.
No comments:
Post a Comment