EQUIPMENT MANAGEMENT- CONTAMINATION CONTROL

 Preface

The presentation given below does not reflect views of any company but rather the product of the knowledge and experience gained through my many years of work as a Service Engineer and Technical Communicator in Tractor & equipment (Ghana) Limited, now Mantrac Ghana and as the Plant Engineer / Chief Operating Officer of Plantgate Equipment Hire Services Ltd. [PEHSL] in Ogun State -Nigeria.

In this presentation, I would share with you some of the wealth of applied experience in a contamination control programme while working with the aforementioned firms, that will be of immerse benefit in prolonging your equipment life.

Introduction

 The sophistication of modern machines (such as earth moving & construction machines, trucks, cranes, utility vehicles, cars and some house hold items used in the performance of some kind of work) has given rise to higher system pressures and/ or tighter internal clearances to meet demands for increased productivity and efficiency. Tighter internal clearance makes system less tolerant to contaminants. Some industry publications¹ quote experts as saying that 75% to 90% of hydraulic systems component (e.g. pumps, motors, cylinders and Valves) failures are caused by system contamination, other fluid system have similar trends. Also a recent Canadian study found out that ‘particle contaminated hydraulic oil’ account for 82% of all wear. Setting cleanliness standards and forming contamination control teams is ‘key’ to achieving success.

My experience and knowledge in contamination control measures were applied on a variety of construction and mining equipment with significant reduction in plant operation and maintenance cost. These measures guaranteed machine availability of up to 90% and about 98% reliability. Considering the degree and frequency of use of these machines, this is a great success and the dependability was made possible by education, paying attention to details, good communication and maintaining clean systems.

Some component manufacturers have robust contamination control programme in place to guarantee the quality of their products. It should be noted that contamination control is not limited to machines, its operations or facilities; some electronics, pharmaceuticals, chemical manufacturing plants, etc. have been known to have good contamination control measures as part of their process plan.

You don’t need a factory or a field environment to start knowing about contamination. Dirt, particles, wear material, oil leaks, etc. found in your piece of equipment when a repairer takes apart your failed item or component; gives you the first noted sign of contamination. Dust, smoke, aerosol, man-made effluent, etc. in your environment are contaminants.

The information here should serve as a guide in fashioning out your contamination control scheme or improvement programme. Help save a little time and cost for yourself, company or nation!

Components & Fluid Lines Covered with Dirt

 

Scope

The Contamination Control initiative should form an integral part of the facility plan and all service operations performed. As long as an equipment remains operational, contamination control measures can considerable give a good reflection on your company’s bottom line. The initiative is best incorporated before a facility setup or initial start up.

The scope of this report will focus more on preventing machine system problems by addressing contamination issues with respect to the facility, equipment, repairs, parts and storage with a little emphasis on fluid contamination. This initiative will go a long way to improve machine performance, reliability, extend component life and lower maintenance and/or operating costs.

 

Know the enemy

The number one enemy of any fluid system is contaminant. Most modern machines/ equipment have closed systems, which may employ one or more form of fluid system for their operation. The only effective way to combat it is to ensure cleanliness at all levels of operations.

 

According to Caterpillar Equipment manufacturer “a half-teaspoon of dirt in a drum (208 liters or 55 US gallons) of hydraulic oil exceeds the contamination allowed in new machines rolling off its assembly lines”.

It is assumed here that all maintenance procedures are duly followed as provided by the manufacturer or technical manuals. Otherwise, you are the number one enemy of your machine or system.

Safety: Follow the safety recommendation outlined in your technical manual when working on your equipment especially on hot or pressurized system.

 

Note: Repairs, maintenance and technical works or analysis must be carried out by only qualified persons.

Benefits of contamination control

      Improves sales and Profitability

      Improve performance & reliability

      Ensures machine availability and value of rental fleet

      Reduces rework

      Improves customer satisfaction and relationship

      Ensures less down time and more efficient repairs

      Lengthens equipment life

      Increases safety

Definition

Contamination as defined by an on-line dictionary is the act of contaminating or polluting; including (either intentionally or accidentally) unwanted substances or factors.

Contaminant - a substance that contaminates a given system. Contaminants are system defined- E.g. for a given hydraulic system: water, rubber wear, dust, metal particles, etc. are contaminants.

System contamination can be defined as any system that contains substance or foreign material that is capable of adversely affecting the system’s performance and/or reliability. It implies that contaminants are not part of any system design and should not be allow into the system.

Contaminants in systems can be classified into two: Particulate and Chemical.

Types

Particulate contaminants: consist of very small, separate solid particles such as sand, plastic or rubber wear, dirt, fiber, and metal particles. Particulates contaminants are more common, controllable, measurable and can originate inside or outside hydraulic systems. Particulates increases wear through abrasive, adhesive, fatigue wear, destroying physical properties of parts and may silt ways as they move through hydraulic systems. The ‘wear materials’ progressively increase particulates in the system further accelerating wear. 

Chemical contaminants: Fluids can have additives added which works to keep the system clean and free from rust, foam and/ or corrosion. Additives could act as a coolant, sealant, etc and could provide a fluid film cushion to reduce friction and wear. An improperly selected fluid or inappropriate additive could result in chemical contamination. Chemical contaminants breakdown the fluid’s chemical compositions producing other contaminants in the form of oxidation products and acids. These may include heat, water, air or fluids from other working systems close by. Chemical contaminants can also originate inside or outside the system.

Internal or external contamination

Contamination sources may originate from inside or outside the system.

Internal contamination which occurs inside the system may be caused by overlooking items requiring specific change-out time, prolonged service intervals, or the use of inferior parts that breaks down during machine operation. E.g. particles can break off from filters, seals, rings, gaskets, etc. after prolong use, resulting in system contamination that may cause abnormal wear of the pumps, motors, valves or other components.

 External contaminations are usually caused outside the system by improper or poor maintenance practices. These include working on the system in a dusty environment or with components in contact or exposed to a dirty environment. Installing  parts or components that have not been properly cleaned or cleaning parts or components with  dirty  rags,  leaving parts or components  uncovered  on  workbenches, on the field or in the workshop.  Transferring fluids in a dirty environment or through dirty hoses, funnels, containers, etc are common occurrence and main cause of fluid contamination on the field.

Source of contaminants

1. Factory or assembly plants: Manufacturing processes and assembly environments often leave contaminants in the system even before the equipment leaves the assembly units. Poor internal component finishing also release a lot of wear from such contact surfaces during the first few hours of operation thereby contaminating the system.
2. Fluid storage: New oil is often contaminated during transportation, transfer and storage.
3. Operating environment: Although most equipment may be designed to work in dirt, their working environment may pose a source of contamination threat to the fluid system integrity.
4. Maintenance and repair works: contaminants may be introduced to the system when system maintenance and repairs are carried out in a dirty environment or using dirty rags to clean components etc.
5. Parts/ Component storage: improper storage or storage in a dirty environment serves as a source of contamination.
6. Machine operation: normal wear in machines are expected during operation, the wear presence are contaminants which are removed during scheduled maintenance as directed by maintenance manual. However, improper machine operation can damage or worsen wear condition that may lead to catastrophic failures. Fluid contamination can also be cause by accidental mixing of two or more fluids in a multi-fluid system. 

 

Effects of contamination

Contamination symptoms are difficult to detect at the on set because their resulting effects may occur slowly over time depending on the type, rate or level of contaminants. Efficiency of a hydraulic system may even drop by as much as 30% before an operator can notice an obvious effect on operation. Some resultant effects are listed below:

• Increases repair and operating cost

• Increases re-work leading to unscheduled downtimes
• Accelerate component wear.
• Can lead to catastrophic failure.
• Reduces component life.
• Reduces efficiency and reliability

Component Rework

 

 Contamination detections

Due to the microscopic nature of contaminants, special or some scientific methods are used to detect and measure their presence. Fluid analysis involves sampling and analyzing fluid for various properties and materials to monitor wear and contamination in the fluid system e.g. engine, transmission, hydraulic, cooling systems etc.

Fluid analysis if well managed can be used for predictive maintenance works by monitoring abnormal levels of particular elements within a system to give an early warning of impending problems and possibly prevent a major breakdown without dismantling the equipment.  Analyses can be carried out on fluids to determine e.g. viscosity, fuel dilution, water, dirt content, fuel soot, component wear, airborne dirt, anti-freeze contamination, and oil additive concentrations.

Analysis of a single sample provides useful information on the existing system fluid conditions before the sample was taken. However, overall condition of your engine or equipment can be better evaluated if samples are taken and analysed at regularly scheduled intervals to create a ‘Trend’ to enable early detection of internal abnormalities.

Fluid Analyses Lab

 

 

Most fluid sample labs can carry out analysis on fuel, oil, water, coolants, etc. which may include but not limited to one of the following:

      Spectrographic analysis of wear metals, oil additives, contaminants. These analyses focus more on wear elements. It identifies and quantifies the elemental constituents present in the oil in parts per million, i.e. about 10 to 15 microns in size.

      Particle count may be performed to determine presence of large metal particles in hydraulic and transmissions applications. It could also quantify any type of particle metals and non-metals, from one micron to 200 microns in size. 

      Total ferrous debris - measurement is based on the ferrous particle contamination.

      Magnetic test - this test is used to identify the source of contaminants if the sample is found to have high levels of metal contamination

      Viscosity checks: Measures oil's resistance to flow. Oil may thin due to shear in multi-grade oils or by dilution with fuel. It may thicken from oxidation when it runs too long or too hot or from contamination by antifreeze and other materials or chemicals.

      Infrared analyses are usually applied to test for engine oil condition and degradation that detects soot, oxidation, nitration, sulphur products, acids. It can also detect contamination by water, fuel and glycol from coolant.

      Hot plate or Crackle test is used to detect initial presence of water by hot plate heat application before other water tests are carried out.

      Coolant analysis- Is a test for coolants properties which determines the presence of water resulting from external/internal condensation or degradation in the coolant.

      TAN (Total Acid Number) and TBN (Total Base Number): Testing is a measure of acidity within oil. It indicates the acid-neutralizing capacity still in the lubricant and is particularly important for engine oil, as it is continuously exposed to acidic combustion products and these must be neutralised before they corrode engine parts.

Taking an Oil Sample

Analysis result will be based only on the sample that you send in for analysis.

Run equipment or engine to operating temperature to ensure the oil is hot and thoroughly mixed before sampling. The fluid testing lab will provide you with the sampling kit.

 

Basically, oil samples can be taken by two methods: 1. Valve sampling. 2. Vacuum extraction.

 

Valve sampling method: In this method a sampling point on the system must be in place or can be installed. Run the engine at low idle until it reaches normal operating temperature. Remove the dust cap from the sampling valve of the compartment and wipe clean. With the machine still running, insert the sampling probe into the valve and draw a small amount of oil into a waste oil container for disposal, then proceed to fill sample bottle from the sampling point to about three-quarters full or the level specified by the oil testing lab. Remove the probe and replace the dust cap and secure the cap on the bottle. Label the sample ready for shipping or to be tested in your company’s lab.

 

Vacuum extraction: For systems without a sample point on the machine, run the system or engine to operating temperature and then stop the engine. Measure and cut new tubing to the length of the dipstick or to such a length that it reaches about halfway into the fluid depth of the given compartment. Using a vacuum pump, insert the measured plastic tubing into the pump and attach the sample bottle. Insert tubing into dipstick hole or the compartment and draw off the sample. Remove the tubing from the bottle and the vacuum pump and secure the cap on the bottle. Label the sample ready for shipping or to be tested in your company’s lab.

 

 

Note: Dispose off used tubing and waste oil safely and responsibly according to your local regulation.

Labeling Sample

Each sample submitted, must have the following information on the sample bottle:

1. Owner or company’s name.
2. Fleet or Unit Number of Machine
3. Machine Make, Model and Manufacturer’s name
4. Compartment from which the sample was taken
5. Number of Hours on Sample.
6. Date the Sample was taken
7. Oil change and oil added
8. Oil type and brand of oil
9. Viscosity
10. Any other comment can be added
    
    

 

 

Sample Result

The sample analysis result will include a list of wear element present and the condition of the physical property of the fluid. The analysis report will compare the test data to a new fluid baseline results. Instant notifications are usually given for samples with excessive metal, particle contamination, fuel dilution or any other serious issues resulting from the test.

 

Test elements

The follow elements are tested for and are usually included in analysis of a sample result:

Silicon (Si): High Si readings generally indicate dirt or fine sand ingestion through air intake system, oil filter plugging, oil filler cap, breather, valve covers, oil supply etc. This would act as an abrasive, causing excessive wear.

Aluminum (Al): High readings can be from thrust washers, bearings and pistons which are made of this metal. Dirt ingestion through air intake system, oil filter plugging, oil filler cap and breather, valve covers, oil supply etc. may cause piston skirt erosion, enlarged ring groove, thrust washers wear, etc.

Lead (Pb): Bearing corrosion or wear will result in very high Pb test result. Extended oil change intervals, use of leaded fuel, dirt intake are associated with bearing wear. The indicators may be an abnormal engine noise or oil pressure, fuel dilution, etc.

Boron, Barium, Calcium, Magnesium, Phosphorous, and Zinc: These elements are usually added to fluids in the form of additives to improve their properties as a detergents, dispersants, anti-foam, anti-rust, etc. An acceptable level of these additives is necessary to guaranty the fluid property to perform its intended function.

 Chromium (CR): High levels of (Cr) can be caused by dirt entry through the air intake or broken rings. Excessive oil blow-by and oil consumption, oil degradation are normally associated with broken piston rings or wear.

Silver (Ag) and Tin (Sn) will indicate wear of bearings resulting in excessive oil consumption, abnormal engine noise, loss in oil pressure, etc.

Iron (Fe): High (Fe) reading indicate wear of cylinder liner, camshafts, crankshaft, valve and gear train, oil pump, rust in system, stuck or broken piston rings, etc. and may be signalled by excessive oil consumption, abnormal engine noise, performance problems, abnormal operating temperatures or oil pressure, etc.

Copper (CU): High (Cu) reading will be from bearings, bushings and valve guide wear, etc. resulting in abnormal engine noise, oil pressure, fuel dilution, coolant in engine oil, etc. The likely cause will be dirt intake, extended oil change intervals, oil cooler failure, radiator corrosion, etc.

Sodium (Na): High Na readings are normally associated with a coolant leak in the system.

Physical Test

In addition to the elemental analysis, physical test results from particle, magnetic test, etc. may be included.

Failure analysis

Failure analysis must be carried out on failed components or parts to ascertain the root cause of a problem with a view of eliminating or preventing future occurrence.

   

Preventive measures

Preventing fluid system problems begins by determining who “the enemy” is and tackling the source of system contamination by taking into account the machine and environment and by involving your staff. The outcome of such an understanding will allow you to develop the countermeasures to be deployed to offset the balance in your favour. The initiative can extend component life, increase availability, reliability and correct problems before they lead to high operating cost or costly repairs and unscheduled downtime.

 A few measures are listed below in no particular order:

• Training: Training staff to understand contamination control is the first step towards any successful initiative. Educate operators, supervisors and service personnel on contamination causes and effects, implementation, control procedures, monitoring and should include the role of every individual. Establish cleanliness standard where everyone knows all about the process and procedure required. Set up a team that monitors the implementation and evaluation of contamination control procedures or assign someone responsible and accountable for contamination control results.

 

• Daily inspection and system monitoring:  An equipment will at least have an instruments that can predict abnormality in the system, e.g gauges, sensors, equipment monitoring systems etc.-report any abnormalities for investigation. Daily inspection of the equipment can detect leaks or other small problems before they result into unscheduled downtime. E.g. Leakages if left unchecked may lead to system contamination and possible failure. That is to say that, if oil can go out, then dirt can come in through the same means. Keep all fluids filled to the appropriate level. Low oil levels may cause poor performance, system overheating, cavitation and then contamination, etc. Do not allow equipment to run out of fuel because that will cause the pump to take fuel from the bottom of the tank that may contain sediment to clog or damage lines, filters, injectors and pump parts.

  Inspect Equipment Daily

     

• Housekeeping: Workshops or repair bays are another major area where contamination occurs so keep all work areas clean and organized, sweep floors daily, clean up spills immediately, keep work benches free of debris, and keep fuel injector rooms closed. Separate processes such as disassembly or cleaning and rebuilding operations.

  Clean Workshop

 

• Oil/ fuel storage and transfer: Select the right type of oil/ fuel for the system as stated by the applicable maintenance and operation manual. Most systems are designed for some specific fluid by taking into consideration the quality of fluid and the additives like oxidants, anti-wear agent and foam inhibitors that help prevent contamination and oil degradation. The use of wrong fluid in any system may lead to wear, contamination, overheating, oil degradation, pressure build up, flow restriction and/or system failure. New oil is clean when it leaves the refinery, however, it may picks up contaminants during transport or during its transfer in a dirty environment or through dirty hoses, funnel, containers, etc. hence new oil/ fuel should always be filtered before use. Fluid in drums should be covered and stored indoors. Ensure lube trucks are fitted with pre-filtering systems to ensure supply of clean fluids. Fluid drained from a system or component should not be reused to safe guard against contaminants.
• Parts handling and storage: Keep components packaged until ready to install, protect all hoses with caps and plugs while in storage. Clean hose or pipe assembly before storage or installation, Limit use of floor for storage without racks, all parts to be returned to storage are to be properly packaged.

  Parts storage

 

• Factory or assembly plants: Some manufacturers set cleanliness targets for equipment and components leaving their plants, others also give a shorter interval for the first preventive maintenance to be carried out where the system can be properly cleaned after few hours of operation. Oil samples should be tested after a short interval (e.g 50- 100hrs) of operation to check the level of contaminants for newly built machines that have just been put to operation. 

  Parts Cleaned & Set Ready for Rebuild

   

 

 

 

 

 

 

Component repair and assembly: All operations must check for cleanliness before and after maintenance and repair works. Service operations must ensure that only clean components are used and in a clean environment for any maintenance and repairs job. All parts and components must remain packaged until ready to install. Do not use fluids in open containers that are stored uncovered or unprotected. In situations where a system or component is serviced with incorrect fluid type, drain fluid, flush system, and replace all packing, filters and gaskets in the affected components or system.

      

Inspecting Machine after Work

• Environmental situation plan will determine initiatives to be taken to control or bar contaminants from systems that may eventually disrupt equipment operation. Field service works should take environment into consideration before carrying out repairs or maintenance work. For indoor equipment or repairs/ rebuild bays, control and monitoring of the environment is another critical factor that must be taken into consideration before initial set-up.

    

• Machine operation: In extremely applications such as rocky, corrosive material, fine dust and debris, protective covers for exposed operating surfaces e.g. hydraulic cylinders and rods are recommended. Inspect and maintain quick couplers or hydraulically driven attachments; wipe off dirt from before coupling. Protect nipples, sample points and couplers with caps and plugs. Operators are to be train on contamination control guidelines and report any noted observation, e.g. excessive drift, temperature, noise and other signs of possible contamination to their supervisors. Operators knowledge of machine operation are to be updated regularly and in-line with the manufacturer’s recommendation in order to avoid machine abuse or accelerating internal wear.
• Technical analysis: Check system pressures, temperatures, cycle time, carry out oil sample analyses, etc. to know and watch machine health and condition. Check system cleanliness of machines if field assembly or attachments are added. Analysis of oil condition and contaminants level can form a cost saving guide for proper oil change intervals. Contact your dealer for details.

  Technical Analysis

 Treating contaminated system

When your sample test result interpretation confirms a contaminated system, prompt action is required to restore the system cleanliness. The longer a contaminated system is operated, the faster components wear out, system efficiency erodes and fluid properties break down.

Identify and correct the cause of elevated contamination levels.  The contaminated system clean up may require the use of high efficiency filters, “kidney loop” filtration, oil changes or complete system flush depending on the contaminant level.

Highly contaminated systems can be serviced by draining the fluid, flushing the system, and replacing all packing, filters, gaskets, etc. where applicable in the affected components or system before refilling with a clean and right type of fluid. Carry out fluid sample analysis to ascertain the status of the system.

Note: follow guidelines as outlined in the technical manuals for such procedures.

1. ¹ Hydraulics & Pneumatics – April 01, 2007, Equipment today- August, 1997, Technical Service Bulletin 96-3R1- Filter Manufacturers’ Council, Machine Design Publication 13-SEP-01

2. Operation and maintenance or technical manuals for Caterpillar, Komastu and Ingersoll rand.

3. Caterpillar’s “Improving fuel system durability” – media number SENR9620

4. Contact any oil sampling lab world wide for their technical brochure

5. Caterpillar’s “Oil and your engine”- media number SEBD0640

6. Caterpillar’s “Optimizing Oil Change Intervals” PEDP7035