2008,safwat,a.,filter analysis describes the history of wear

7/28/2019 2008,Safwat,A.,Filter Analysis Describes the History of Wear

1/3

Filter Analysis Describes the History of

Wear

Ahmed Safwat, Cemex Egypt

Across-bar cooler is one of the main pieces

of equipment in cement production. It isused for the transport and cooling of

clinker, one of the ingredients of cement.Cement kilns operate with a cross-barcooler which consists of four grates drivenby a hydraulic station.

Any pump failures cause downtime andstop cement production. Therefore, it is

important for the pump to operatesmoothly on continuous basis.

Hydraulic Circuit

Pilot Pump

The pilot pump provides oil flow to theproportional valve which controls the

position of the swash plate. It also controlsthe oil flow from the main pump (axial piston pump) at 22 liters per minute.

Boost PumpThe boost pump refills the main pump with the same amount of oil removed by the shuttle

valve to cool the oil. Oil flow is 50 liters per minute.

Main Pump

The main pump consists of an axial piston pump with variable displacement and variable

direction. It provides flow in two directions (174 to 214 liters per minute) and controls themovement of the grates.

Closed-loop Circuit

In a forward direction, the pump suction comes from Port B (low-pressure side). Oil flow fromPort A (high-pressure side) flows forward across the grate. When the swash plate position is

reversed, the pump suction from Port A (low-pressure side) changes the direction of oil flow.Oil flow from Port B (high-pressure side) moves across the grate in reverse direction.

What HappenedDuring a routine filter change, the technician noticed a large amount of metal wear debris inthe bowl filter. An internal inspection revealed a problem in the boost pump. Because it was apressure-line filter of the boost pump, the technician collected all metal from the bowl andanalyzed it visually using an optical microscope. Wear particles larger than 100 microns were

observed (Figure 1), and an emergency warning was issued to change the pump and filterimmediately before the failure caused the machine to stop.

Figure 1. Surface striations caused by the severe abrasive wear mechanism before theparticle was removed.

ResultsThe gear pump was replaced. To confirm that the defect actually existed, the pump wasopened and visually inspected.

Close-up photos of the housing and gear of the defective pump show severe wear damage

Nov / Dec 2008

Past Issues

HomeTraining/Events

NewsletterAdvertise

Buyers GuideMessage Boards

BookstoreDictionary

Contact Us

Equipment ReliabilityMade Visual

Solid-State ViscositySensors for Condition

Monitoring

Creating an EffectivePlant Lubrication

Program

FluidScan HandheldLubricant Condition

Monitor

Practicing Oil AnalysisMachinery Lubrication

Reliable PlantLube-Tips

Reliable Plant MailLean Manufacturing

Most Popul

Articles:

How to ReadOil Analysis Re

How to AnalyGear Failure

Oil Sampling Ad

ilter Analysis Describes the History of Wear http://www.oilanalysis.com/article_detail.asp?articleid=1770

of 3 4/22/2007 9:11 PM


2/3

(Figure 2).

Figure 2. Gear Housing

ConclusionWear particles collected by the oil filter were inspected using a microscope. It was concluded

that the filters contained wear particles which characterize the most significant mode of pumpwear. The filters remove and store metallic particles generated from the rubbing surfaces.

The size and morphology of wear particles collected in the oil filters are larger than thosedeposited by ferrography.

The history of wear and early failure of the sliding surfaces can be seen by following thestriation marks caused by abrasion (Figure 1). The varying colors of wear particle surfaces

reveal specific information about the temperature of the sliding surface from which the wearparticles were removed.

Figure 3. Gear of Defective Pump

About Portland Cement

Cement is made by heating limestone with small quantities of other materials (such as clay)

to 1,450C in a kiln. The resulting hard substance, called clinker, is then ground with a smallamount of gypsum into a powder to make "ordinary Portland cement", the most commontype of cement (often referred to as OPC).

Portland cement is a basic ingredient of concrete, mortar and most non-specialty grout. Themost common use for Portland cement is in the production of concrete. Concrete is a

composite material consisting of aggregate (gravel and sand), cement and water. As aconstruction material, concrete can be cast in almost any shape desired and, once hardened,

can become a structural (load-bearing) element. Portland cement may be gray or white.

Reference

http://en.wikipedia.org/wiki/Cement

Clinker

According to Merriam-Webster, clinker is defined as: 1) a brick that has been burned toomuch in the kiln, or 2) stony matter fused together, slag.

Referencewww.merriam-webster.com/dictionary

About the Author

Ahmed Safwat Hassan is a preventive and predictive maintenance manager at CEMEX in Egypt. CEMEX is a buildingmaterials supplier, providing cement and concrete products to cons truction projects in various sectors: indust rial,commercial, residential and municipal. For more information about CEMEX, visit www.cemex.com.

Please reference this article as:

Ahmed Safwat, Cemex Egypt, "Filter Analysis Describes the History of Wear". Practicing Oil

Analysis Magazine. November 2008

Issue Number: 200811

Practicing Oil AnalysisCase Study

Detect and ConWater In Oil


of 3 4/22/2007 9:11 PM


3/3

2009 Noria Corporation


of 3 4/22/2007 9:11 PM

2008,safwat,a.,filter analysis describes the history of wear

Documents