Hydraulic fluids:Neutralization number

Neutralization number

The neutralization number is a measure of the relative acidity or alkalinity of a hydraulic fluid and is specified by the pH level. A fluid having a smaller neutralization number is recommended, as high-acidity or high-alkaline fluid can cause corrosion of metal parts as well as a deterioration of seal and packing glands.

For an acidic fluid, the neutralization number equals the number of milligrams (mg) of potassium hydroxide necessary to neutralize the acid in a 1 g sample. In the case of an alkaline fluid, the neutralization number equals the amount of alcoholic hydrochloric acid that is necessary to neutralize the alkali in a 1 g sample of hydraulic fluid. With use, hydraulic fluid normally has a tendency to become more acidic than basic.

The neutralization number of a hydraulic fluid can be determined by the following test procedure as illustrated by Figure 8.2.

The oil sample is placed in a titration solution of distilled water, alcohol, toluene and an indicating agent known as naphthol benzene, which changes color from orange to green when neutralization occurs.

Alcoholic potassium hydroxide is added from a burette drop by drop, until the solution changes its color from orange to green. The neutralization number is then calculated using the following formula,

Hydraulic fluids-0212

Hydraulic fluids, which have been treated with additives in order to inhibit the formation of acids, are usually able to keep this number at a low value of 0 or 0.1.

Hydraulic fluids-0213

Incoming search terms:

Related posts:

Benefits, drawbacks and operational issues:Power drive system integration
Variable speed drives:Variable speed drives for other AC motors
Pumps:Pumps in series switched to meet demand
Air movers:Air compression effects and Delivery temperature.
Low pressure and vacuum:Suction nozzles and Feed rate control.
Low pressure and vacuum:Air leakage
Introduction to pneumatic conveying and the guide:Pneumatic conveying and System flexibility.
COMPRESSORS:COMMON COMPONENTS
BASIC DIAGRAMS AND SYSTEMS:Controlled Pressure Clamping Circuit
RESERVOIRS, STRAINERS, FILTERS, AND ACCUMULATORS
Hydraulic circuit design and analysis:Symbols of hydraulic components
The flapper-nozzle.
Graphic symbols.
Compressor types:Piston compressors,Screw compressors,Rotary compressors and Dynamic compressors.
ENTROPY:PROPERTY DIAGRAMS INVOLVING ENTROPY

Leave a comment

Your email address will not be published. Required fields are marked *