Hydraulic fluids classification

Table 8.5 ISO 6743-4 1999 Hydraulic fluid classification for hydrostatic systems...

Fire-Resistant Hydraulic Fluids. The four classifications of fire-resistant hydrauHc fluids are Hsted below (7). Three of the four groups are fire resistant because they contain a significant amount of water which provides cooling and blanketing of the combustible materials. 

Some U.S. governmental lubricant requirements for nontactical equipment is now acquired as Commercial Item Descriptions (CID), rather than against specific military numbers. A new classification system for shear-stable, high VI hydraulic fluids was balloted by ASTM in 1994. 

Fluids for Hydraulic Transmissions-Fire Resistant Fluids—Classifications, Provisional Recommendation RP7.7H, European Oil HydrauHc and Pneumatic Committee, 1976. 

DRILLING MUD HYDRAULICS Rheological Classification of Drilling Fluids... 

This is the energy source for hydraulic systems. It converts electrical energy into dynamic, hydraulic pressure. In almost all cases, hydraulic systems utilize positive displacement pumps as their primary power source. These are broken down into two primary sub-classifications constant-volume or variable-volume. In the former, the pumps are designed to deliver a fixed output (i.e. both volume and pressure) of hydraulic fluid. In the later, the pump delivers only the volume or pressure required for specific functions of the system or its components. 

Table 52.7 CETOP classifications of fire-resistant hydraulic fluids...

The dilution factor can be automatically computed to give absolute counts for liquids as dense as sludge. Supercount is also loaded with a special program for hydraulic fluids and phi classification. 

In terms of their chemistry, hydraulic lubricants are divided into four classes (i) mineral oil-based products, (ii) synthetic lubricants, (iii) emulsions, and (iv) water-based fluids. Biodegradable hydraulic fluids are a new ISO classification group and will be described separately. 

The first aircraft hydraulic fluid was castor oil based. Modern aircraft now use one of two broad classifications of hydraulic fluid, hydrocarbon based or phosphate ester based. 

Two ores, of densities 3700 and 9800 kg/m3 are to be separated in water by a hydraulic classification method. If the particles are all of approximately the same shape and each is sufficiently large for the drag force to be proportional to the square of its velocity in the fluid, calculate the maximum ratio of sizes which can be completely separated if the particles attain their terminal falling velocities. Explain why a wider range of sizes can be... 

Stambaugh, R.L., Kopko, R.J. and Roland, TF. (1990) Hydraulic pump performance - a basis for fluid viscosity classification. SAE Paper 901633. 

Control valves can be broken into two major classifications process and fluid power. Process valves control the flow of gases and liquids through a process system. Fluid-power valves control pneumatic or hydraulic systems. 

In some classification applications, the required cut point is very sharp and the rheology of both separated phases is such that they remain quite fluid. In this type of application the pond used would be relatively deep, and separation would be akin to a liquid/liquid separation, using a hydraulic balance under some form of baffle. 

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