Image analyzer

A sophisticated microscopic system involving a microscope, a television camera, a dedicated computer, and a viewing monitor similar to a television screen.

Immiscible

Incapable of being mixed without separation of phases. Water and petroleum oil are immiscible under most conditions, although they can be made miscible with the addition of an emulsifier.

Indicator

A device, which provides external evidence of, sensed phenomena.

Indicator, differential pressure

An indicator, which signals the difference in pressure between two points, typically between the upstream and downstream sides of a filter element.

Indicator, pressure

An indicator that signals pressure conditions.

Influent

The fluid entering a component.

Infrared spectra

A graph of infrared energy absorbed at various frequencies in the additive region of the infrared spectrum. The current sample, the reference oil and the previous samples are usually compared.

Infrared spectroscopy

An analytical method using infrared absorption for assessing the properties of used oil and certain contaminants suspended therein. See FTIR.

Ingested contaminants

Environmental contaminant that ingresses due to the action of the system or machine.

Ingression level

Particles added per unit of circulating fluid volume.

Inhibitor

Any substance that slows or prevents such chemical reactions as corrosion or oxidation.

Insoluble

Particles of carbon or agglomerates of carbon and other material. Indicates deposition or dispersant dropout in an engine. Not serious in a compressor or gearbox unless there has been a rapid increase in these particles.

Intensifier

A device, which converts low-pressure fluid power into higher-pressure fluid power.

Interfacial tension (IFT)

The energy per unit area present at the boundary of two immiscible liquids. It is usually expressed in dynes/cm (ASTM Designation D 971.)

ISO

International Standards Organization, sets viscosity reference scales.

ISO Solid Contaminant Code (ISO 4406)

A code assigned on the basis of the number of particles per unit volume greater than 5 and 15 micrometers in size. Range numbers identify each increment in the particle population throughout the spectrum of levels.

ISO viscosity grade

A number indicating the nominal viscosity of an industrial fluid lubricant at 40¦C (104¦F) as defined by ASTM Standard Viscosity System for Industrial Fluid Lubricants D 2422. Essentially identical to ISO Standard 3448.