Strategically located in the flow stream to collect a representative sample of wear debris circulating in the system: for example, engine swarf, bearing flakes, and fatigue chunks. The rate of buildup of wear debris reflects degradation of critical surfaces.



Related Terms

GALLING

A form of wear in which seizing or tearing of the gear or bearing surface occurs.

CUTOFF POINT

  1. The point at which there is a transition from spiral flow in the housing of a centrifugal fan to straight-line flow in the connected duct. 2. The point on the stroke of a steam engine where admission of steam is stopped.

FATIGUE CHUNKS

Thick three-dimensional particles exceeding 50 microns indicating severe wear of gear teeth.

SCUFFING

Abnormal engine wear due to localized welding and fracture. It can be prevented through the use of anti-wear, extreme-pressure and friction modifier additives.

BIG END BEARING

A bearing at the larger (crankshaft) end of a connecting rod in an engine.
The bearings are made of cast steel and each consist of an upper and lower part secured to the connecting rod by means of fitting bolts, the nuts of which are secured. Compression shims are provided between the bottom end bearing and the palm of the connecting rod.
The bearings have white metal bearing surfaces provided with lubrication grooves for the necessary supply of lubricating and cooling oil. Shims of different thickness are inserted between the shells to enable adjustment of the bearing clearances (approx. 0.20-0.30mm).

BOTTOM END BEARING

A bearing at the larger (crankshaft) end of a connecting rod in an engine.
Made of cast steel and each consist of an upper and lower part secured to the connecting rod by means of fitting bolts, the nuts of which are secured. Compression shims are provided between the bottom end bearing and the palm of the connecting rod.
The bearings have white metal bearing surfaces provided with lubrication grooves for the necessary supply of lubricating and cooling oil. Shims of different thickness are inserted between the shells to enable adjustment of the bearing clearances (approx. 0.20-0.30mm).

FATIGUE PLATELETS

Normal particles between 20 and 40 microns found in gear box and rolling element bearing oil samples observed by analytical ferrography. A sudden increase in the size and quantity of these particles indicates excessive wear.

ABRASIVE WEAR

Abrasive wear is caused by hard particles such as ash deposits, metallic particles or catalytic fines from the cracking process of the fuel oil. These hard grains wear down the surface of cylinder liners and rings by continuous ploughing and scratching.
With higher levels of abrasive wear, the surface displays vertical scratches, the size of which depends on the dimensions of the particles involved. These particles can also affect the sides of the rings as they jam in the ring groove, thereby causing "pitting" of the surface. Harmful particles normally enter the engine via the fuel and careful attention to the fuel cleaning system is therefore of utmost importance. abbrasive wear pic

BELLOWS GAS METER

A device for measuring the total volume of a continuous gas flow stream in which the motion of two bellows, alternately filled with and exhausted of the gas, actuates a register.

TURBO CHARGER

The blades of a turbine in the outlet exhaust flow of an engine are driven by the gases flowing over them. Compressor blades at the other end of the same axle are spun in the inlet flow, drawing large volumes of air into the cylinders. This enables faster combustion than naturally aspirated engines and increases power of the engine.

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