1. Найдите производные следующих слов. Определите, какой частью речи они являются. Воспользуйтесь словарем, если необходимо. Переведите на русский язык:

Combine, cause, produce, oxygen, soluble, machinery, perform, protection, lubricate, moisture, adequate, appropriate, particularly, gravity

2. Переведите следующие словосочетания на русский язык. Объясните, чем выражено определение в этих словосочетаниях:

Oil oxidation, breakdown products, special oxidation inhibitors, chain reactions, oil degradation, rust inhibitors, close tolerance valve, wear protection, wear protection requirements, wear resistance, carbon and ash content, purchase specification

3. Проанализируйте следующие предложения с грамматической точки зрения. Переведите их на русский язык:

1. Such inhibitors are particularly necessary for any oil to be used in systems with close tolerance valves

2. To meet these increased demands special antiwear additives have been developed.

Properties of Hydraulic Fluids

Oxidation: Oxygen is probably the greatest enemy of hydraulic fluids. Oxygen combines with the fluid causing chemical changes that produce acidic products and sludges. The more acidic products of oxidation can pit and corrode metal surfaces. Also formed through oxidation are:

1. Soluble resins that turn to vanishes and lacquers upon contact with hot metal surfaces;

2. Insoluble sludges that clog small orifices, jam tightly fitted parts and upset the balance of the system.

Thermal Degradation: Heat is another major enemy of hydraulic oil. For every 18-20 F rise in temperature above the average operating temperature of 130 F the life of the oil is reduced by 50%. Elevated temperature accelerates oil oxidation, producing breakdown products that serve as catalysts to further breakdown of the oil. Use of special oxidation inhibitors serve to ”cut-off” so called chain-reactions that cause oil degradation.

Inhibitors provide protection to the oil so that it can perform in machinery under the more severe operating conditions. However in performing their function the inhibitors are consumed. Therefore protection is not indefinite and oil must be replaced at recommended intervals to retain active inhibitors.

Metal-Part Protection: Most hydraulic systems accumulate some moisture, from which oils in their natural state do not usually provide adequate protection against rust and corrosion. Therefore, appropriate rust inhibitors are added to most hydraulic oils. Such inhibitors are particularly necessary for any oil to be used in systems with close-tolerance valves.

Under normal conditions oil with the correct viscosity has sufficient lubricity to adequately lubricate all running parts and provide necessary wear protection. But when abnormal loads and temperatures are encountered, the lubricity and wear-protection requirements increase sharply. To meet these increased demands special antiwear additives have been developed. Use of these additives in conjunction with appropriate rust and oxidation inhibitors, provides hydraulic oil with excellent wear resistance and rust and oxidation protection.

Antifoam: Hydraulic oil foaming, a result of air entrainment, can be controlled through use of antifoam additives in most hydraulic oils. These additives should be specified for systems where proper baffling and return-line configuration are ineffective in controlling foaming.

Nonessential Properties: The properties described so far can be considered essential for most systems. Several other properties on the other hand have little to do with hydraulic system use: gravity, flash point, color, neutralization number, carbon content and ash content, though often detailed in purchase specifications, are typically not essential to good hydraulic performance. 2789