Iy. Give a short summary of Text 4. Text 5

1. Pronounce the following words:

Naphthenic oils, paraffinic oils, mixed-based oils, intermediate viscosity, marginally, rust and oxidation oils, antiwear oils, extreme-pressure oils, antileak oils, industrial detergent oils, fire-resistant fluids.

2. Characterize each sort of oil.

Types of Hydraulic Fluids

Naphthenic oils are characterized by low viscosity index and low poor point, so they are suitable for low to medium-temperature operation. These oils can be used with both active and inactive filter media.

Paraffinic oils have a high viscosity index and a somewhat higher poor point than naphthenic oils. They are suitable for medium and high-temperature operation. They can be used with both active and inactive filter media.

Mixed-based oils, as the term indicates, are blends of naphthenic and paraffinic oils, with mixture properties varying with the blend ratios. Often referred to as intermediate viscosity- index oils, they may (depending of ratio) be suitable for either high or low-temperature operation, or marginally satisfactory for both. Like both parent grades, they are suitable for both active and inactive filter media.

Rust and oxidation oils are naphthenic, paraffinic and mixed-base oils inhibited to give varying degrees of rust and oxidation protection. Highest quality blends that are known as "R&O turbine quality", lower quality blends that are still suitable for many hydraulic applications are designated "R&O less-than-turbine quality". The varying levels of rust and oxidation inhibitors can be removed by active filters, R&O oils must be used with inactive media only.

Antiwear oils may be of naphthenic or paraffinic base and may include R&O protection. In addition to base properties , They have antiwear additives that minimize wear of moving metal parts in the system components. Use with inactive filter media only.

Extreme-pressure oils are designed especially to lubricate machine tool "ways" as well as transmit power and lubricate the hydraulic-system moving parts. These oils contain an additive to enhance slipperiness, plus a special extreme-pressure (EP) additive to prevent jerky "stick-slip" way operation. The special additives are normally added only in base oils, or base oils with rust inhibitors, so EP oils commonly cannot offer antileak, antioxidation or improved-viscosity performance. EP oils are not considered especially suitable for either high or low-temperature operation and can be used only with inactive filter media.

Antileak oils reduce leakage through the use of special additives that maintain seal pliability. These oils are typically suitable for low-temperature startup but not for high-temperature operation. Protected against rust and corrosion, they offer a long service life when used with inactive filter media.

Industrial detergent oils are most often used in mobile equipment exposed to dirty conditions. They offer long service life, plus protection from rust, wear, foam and abnormal contamination. Viscosity index is high, allowing operation over a wide range of temperatures. Because many additives could be removed by an active-media filter, detergent oils are best used with inactive filter media.

Fire-resistant fluids consist of water-oil emulsions (both regular and invert), water-glycol and synthetics, including phosphate-ester and chlorinated-hydrocarbon fluids. The water-base fluids depend on water content for fire resistance, but the synthetics have fire-resistance inherent in the major fluid component. These fluids, covered in depth in a recent article, provide reduced effectiveness in a nearly all areas they are used only by their resistance to fire. No simple fire-resistant fluid can handle both low and high-temperature operation, and some fluids offer scant resistance to rust, wear, foam or leakage. They must be used only with inactive filter media. 3567