Hydraulic Fluid Selection Guide

A. MARKETING COMPARISON

TYPE PRICE
High water based fluids $5-8
Water glycol $3-6
Polyol ester $5-8
Phosphate ester $10-15
Synthetic Polyol $7-10

 

B. RELATIVE MERITS AND DEMERITS

High water based fluids - merits

. lowest cost
. environmentally acceptable - biodegradable
. easy to clean up spills
. not harmful to workers or clothing
. no special seals required
. excellent waste treatability
. most safety - Hydratech 2000 is non-flammable
. low wear rates in vane pumps up to 14 mPa (2000 psi) and 30 mPa (4500 psi) in selected piston pumps
. field performance proven
. shear stable viscosity
. system operates cooler due to water content

High water based fluid - Demerits
. will freeze below 2oC, thus cannot be directly used from outside winter storage in some area 
. limited to 14 mPa (2000 psi) in vane pumps due to water vapour pressure
. sensitive to high temperatures due to water content - maximum 60 oC recommended

Conventional Water Glycol Merits
. moderate anti-wear performance up to 14 mPa (2000 psi) in vane pumps
. excellent low temperature characteristics
. high viscosity index
. widely used
. field proven
. very good fire resistance
. no special seals required

Conventional Water Glycol Demerits
. more expensive
. spills do not dry and make surfaces slippery
. can be corrosive to metals
. low cost versions do not give long equipment life due to low anti-wear performance
. limited to 1500 - 2000 psi in vane pumps
. sensitive to high temperature due to water content - maximum 60 oC recommended

High Performance Water Glycol Merits
. good anti-wear performance in selected vane pumps up to 21 mPa (3000 psi)
. excellent low temperature characteristics
. very high viscosity index
. field proven performance
. very good fire resistance
. no special seals required


High Performance Water Glycol Demerits
. more expensive
. spills do not dry due to glycol


Polyol Ester Merits 
. very good anti-wear performance
. environmentally acceptable
. good waste treatability
. field performance proven
. no special seals required
. high viscosity index


Polyol Ester Demerits
. more expensive
. poor fire resistance, supports combustion
. low oxidation resistance leads to gummy deposits in systems


Phosphate Ester Merits
. excellent anti-wear and lubricity
. can be used at very high pressure
. very high thermal stability
. good fire resistance
. widely used, field proven


Phosphate Ester Demerits
. high cost
. low viscosity index for pure phosphate esters
. special seals required

Synthetic Polyol Merits
-


Symthetic Polyol Demerits 
The information contained herein is considered to be correct but should only be taken as a guideline. No guarantee or warranty is expressed or implied for the product described and we assume o responsibility 
for its use.