Evaluating a hydraulic pump test

62 M A R C H 2 0 0 7 T R I B O L O G Y & L U B R I C A T I O N T E C H N O L O G Y

By Jack Poley

On Condition Monitoring

n this month’s column, we’ll do an evaluation on ahydraulic pump test result, given the following infor-mation about this component:

• Equipment type: Molding Machine

• Equipment manufacturer: EasyMold

• Equipment model: 13

• Component type: Hydraulic Pump

– Sub-type: Vane

• Component manufacturer: not provided

• Component model: not provided

• Application: Injection Molding

• Lube manufacturer: A-1 Lubes

• Lube brand: HydroLube

• Grade: ISO 46

• Filter type: Full-Flow

• Filter manufacturer: FilterWell

• Filter brand: HydroFilter

• Filter rating (nominal): ?

• Sump capacity: 9 gallons

While the above information is standard when a com-ponent is placed into a testing program, often informationis missing such as the component manufacturer/modelabove. Items in bold are the most important informationto have. Let’s first review the purpose, importance andhierarchy of some of these fields for which we’d prefer tohave information:

Equipment type. The overall machine or installation;examples:

• On-Road: truck, tractor, rig.

• Off-Road: scraper tractor, haul truck, crusher,dragline.

• Oil & Gas: drilling rig/platform, pipeline station.

• Industrial: manufacturing plant no. 4, power plant,mill.

• Marine: tugboat, container ship, cruise ship.

Equipment manufacturer/model. It’s not always easy toknow the component manufacturer of the sump fromwhich the sample came, sometimes because the compo-

nent is private labeled. Occasionally in such instances theequipment manufacturer can be substituted as a helpbecause many OEMs (original equipment manufacturers)use single-source suppliers for their componentry, creat-ing a form of ‘standardization’ within the test data. Knowl-edge of the equipment model also may help ‘age’ themachine, i.e., allow the evaluator to know the age of thecomponent from which the sample came.

Component type: no component type, no evaluation. Itshould be crystal clear that not knowing from whence the sam-ple emanated, one has no business trying to evaluate it. Neverthe-less, liberties are taken almost daily in large volume com-mercial labs but with a high degree of insurance built in,e.g., a long-time customer has 100-plus components on aprogram, all of which are diesel engines (various mix ofmanufacturers). A new unit is put into play and its engineis sampled and sent to the lab. The person logging in thesample makes the reasonable assumption that this newcomponent is, like all the others, a diesel engine, but can-not identify its manufacturer, let alone the model. Further,he sees the sample is pitch black, confirming his assump-tion that it’s (probably) a diesel engine. This is OK, pro-vided one chases down the missing information and veri-fies the initial assumption sooner rather than later.

Better is for the end-user to do right the first time andget in the habit of providing full information at the outsetof a program and with each addition, change or substitu-tion of a component thereafter. Here are examples of com-ponent types:

• Hydraulic Pump (generic)■ Vane (specific)■ Axial Piston■ Gear

• Gearbox (generic)■ Gearbox, Hypoid gear set (specific)

• Reciprocating Engine (lots of engines reciprocate!)■ Diesel (big, little, using no. 2 fuel or no. 6 fuel?,

air-cooled or water-cooled?)■ Steam

• Transmission, Manual (or Automatic or Powershifttype?)

I

Evaluating a hydraulicpump test

T R I B O L O G Y & L U B R I C A T I O N T E C H N O L O G Y M A R C H 2 0 0 7 63T R I B O L O G Y & L U B R I C A T I O N T E C H N O L O G Y M A R C H 2 0 0 7 63

Application. How is this component being utilized—orabused? This information is highly important in terms ofassessing data severity. It is obvious that environmentalconditions, load, duty cycle, etc., are critical aspects toexpected wear, contamination and lube degradation.Examples of applications:

• On-Road: Primarily OTR (Over-the-Road) tractor/trailers and straight trucks, which should be differen-tiated by duty cycle.

■ Line Haul■ Pickup/Delivery

• Off-Road (general)■ Mining (generic)

▼ Coal (specific)❚ Surface (more specific)❚ Underground

▼ Copper▼ Titanium

■ Forestry■ Construction

Lube manufacturer/brand. As stated in previouscolumns, knowing who made the lube is not particularlyuseful unless the specific brand of the lube is included (itis true that a manufacturer noted for making a very dis-tinctive lube, such as one with a molybdenum sulfideadditive package, would be of use to know, even in theabsence of the specific brand; but this is the exceptionthat suggests the rule). Why is this so? Because differentbrands, within the same manufacturer, exhibit differentproperties and contain additive variations or stark differ-ences, in some cases. Not knowing the ‘target’ precludesassessing the data with confidence.

Grade. There is little point in performing a viscosity, a derigueur test in oil analysis, without knowing what valueshould be expected in the absence of problems—again, acase of not knowing the ‘target.’ Too many things canchange a viscosity upward or downward to be able to haveconfidence, if one doesn’t know the lube grade at evalua-tion time.

Filter information. Primarily to track basic product per-formance, but it’s also nice to know the expectations withrespect to the filter’s rated performance (Beta ratio andsimilar particle control characteristics). Tough luck, youdon’t get it this time.

OK, we now have all the information we’re likely to get forthis component. Below are data from the current sampletesting (leftmost result column), as well as three priorsamples.

Ground rules:• Any test result not shown was ‘not a factor’ or was not

performed; maybe you think some additional analyt-ical work needs to be done? Note: Additive metalswere at ‘proper or expected levels,’ typical of the lubeproduct this component normally uses, so you need-n’t be concerned there.

• Flagged values are based on a reasonable statisticalset and math treatment, i.e., the data are comparedto like machinery.

■ Light Green: ‘Notable’■ Yellow: ‘Abnormal’■ Orange: ‘High’■ Red: ‘Severe’

• Time on the lube is comparable for each sample.• This customer is only interested in a two-part ISO

particle count code.

Have at it. What would your comments be? You’ve gottwo months to evaluate the sample belwo, so you ought todo a good job. A typical commercial lab’s evaluator has lessthan a minute per sample to make up his/her mind. <<

Jack Poley is managing partner of Condition Monitoring Interna-tional (CMI), Miami, consultants in fluid analysis. You can reachhim at poleyj@bellsouth.net. For more information about CMI,visit their Web site: www.cmiglobal.biz.