Maintenance of Construction Equipment - Lubricants

4. Reliability Centered Maintenance

Basic philosophy

• Utilizes predictive/preventive maintenance methods with root cause failure analysis to find out and pinpoint the exact problems,along with advanced installation and repair techniques, including potential redesign or modification of equipment to eliminate the occurrence of the problems.

Reliability centered maintenance (RCM) magazine gives the following definition of RCM: “RCM is a process used to determine the maintenance requirements of any physical asset in its operating context.” Generally, RCM methodology deals with some important issues not dealt with by other maintenance policies. It recognizes that all equipment in a facility does not have equal importance to either the process or to facility safety. It identifies that equipment design and operation differs and that different equipment is more prone to failures from different degradation process than others. It also advances the structuring of a maintenance program recognizing that a facility does not possess unlimited financial and personnel resources and that the use of both is to be prioritized and optimized. In brief, RCM is an efficient approach to evaluating a facility’s equipment and resources to best mate the two and result in a high degree of facility reliability and cost-effectiveness. RCM highly depends on predictive maintenance but also recognizes that the maintenance tasks on equipment that is inexpensive and not important to facility reliability may best be done with a reactive maintenance approach.

Advantages

• Lower costs by eliminating unnecessary maintenance or overhauls.
• Can be the most efficient maintenance program.
• Minimize frequency of overhauls.
• Able to focus maintenance activities on critical components.
• Reduced probability of sudden equipment failures
• Incorporates root cause analysis.
• Increased component reliability.

Disadvantages

• Savings potential not readily seen by management.
• Can have significant startup cost, training, equipment, etc.

Repair or Replace

One of the equipment manager’s most critical duties is to determine whether to repair or replace the component of construction equipment. Since profit maximization is sought by a contractor, productivity improvements built into new equipment might cause a manager to procure the new one and dispose of the old one. This case may arise even if the maintenance is managed very well and the productivity of the old equipment is comparatively high while the cost of operation is comparatively low. Maintenance management and its effect play a vital role in the ultimate decision since the residual value of the currently owned equipment derive from how it has been operated and the efficiency of maintenance.

Lubricants, uses, storage and their specification

Lubricants are materials especially used for lubricating mating parts to reduce friction so that the life of equipment will be increased.

Functions of lubricants:

1. Lubricate the mating parts to reduce friction
2. Cool the aggregates
3. Clean or separate metal chips or foreign material from lubricant to prevent rapid wear
4. Seal (piston rings and cylinder)
5. Works as working medium to transfer energy.

Uses of lubricants

Lubricants are used in various aggregates:

1. Engine oil
2. Air filter oil
3. Transmission or gear oil(gear box, differential)
4. Hydraulic oil ( hydraulic system)
5. Grease (chain, wheel and axle bearing, grease cup etc.)

Storage of lubricants

Two types of storage of oil:

1. Outdoor storage
2. Indoor storage

1. Outdoor storage of oil:

• The temporary shelter should be provided to protect the oil drum or packing or container.
• Tarpaulin (cover) should be spread over the drum to protect from different weather condition.
• Drums of different grades of oil should be kept separately giving brand name and specification.
• Before removing bung (cap) of a drum, should dry and wipe them thoroughly and clean surrounding surfaces.
• Keep away from storage of other inflammable material.
• Don’t allow to smoking near storage area.
• The oil drum should be put on wooden planks to keep them above the ground which prevents rusting of an underside of a drum.
• The wooden planks should be given slight slope for draining of water and other liquid.
• The drum should be set securely so that it should not slide down.
• Should inspect regularly to detect leakage and prevent it.
• The drums should be stored in maximum in three layers, better in two layers.
• The Wooden ramp must be used to remove the drum from an upper level.

2. Indoor storage of oil

• The oil drum should be put on wooden planks to keep them above the ground which prevents rusting of underside of drum
• Racks and cupboards should be properly arranged for keeping oil packing or small containers.
• Racks or cupboards must be provided for storing oil can, grease guns, clocks etc.
• Metal trays should be provided with a container to catch drips oil.
• Oil drum should be covered while taking from store to workplaces to avoid any contamination with dust or dirt.
• Metallic pad or suitable tool should be used to pick up or draw grease.
• Drums of different grades of lubricant should be kept separately giving brand name and specification for easy identification.
• Keep away from storage of other inflammable material
• Don’t allow to smoking near storage area

Specification of lubricants

Approved engine oils are divided into the following MTU Quality Categories:

• Oil category 1: Standard quality / Single and multi-grade oils
• Oil category 2: Higher quality / Single and multi-grade oils
• Oil category 2.1: Multi-grade oils with a low ash-forming additive content (low SAPS oils)
• Oil category 3: Highest quality / Multi-grade oils
• Oil category 3.1: Multi-grade oils with a low ash-forming additive content (low SAPS oils)

Selection of viscosity grades

Selection of the viscosity grade is based primarily on the ambient temperature at which the engine is to be started and operated. If the relevant performance criteria are observed the engines can be operated both with single grade and multi-grade oils, depending on the application. Standard values for the temperature limits in each viscosity grade are shown in (Figure 1). If the prevailing temperature is too low, the engine oil must be preheated.

Example:

For Petrol engine

SAE 20W40 API SL _ used for petrol engine

SAE: Society of Automotive Engineers

20W- 40 – viscosity index- used in all seasons

W- winter (20w- used in winter seasons)

40 – used in summer seasons

API- American Petroleum Institute

S- Spark Ignition Engine

L – grade : SA,SB,SC,SC,SE……SL………

For Diesel engine

SAE 20W50 API CF4 – multi-grade for diesel engine

SAE 80,90………………. Gear oil

SAE 46…………………….hydraulic oil

References

1. Technical book, “Construction Machinery Training”, Instate, Imlambad
2. Harris, F. and McCaffer, “Management of Construction Equipment”, Macmillan Education Ltd. London, UK.
3. Erich J. Schulz, “Diesel Equipment I and II”, Mcgraw-Hill book co.
4. Frank Harries, Ronald McCaffer, “Construction of Plant Excavating and Material Handling”, Granda Publishing.
5. SAE Handbook Volume 4
6. “Caterpillar performance Handbook”, Edition 33, Caterpillar Inc, Peoria, Illinois, USA.