Thickened Water-Glycol Hydraulic Fluids for Use at High Pressures

A recently developed and patented class of high-performance thickened water-glycol hydraulic fluids that can be used in applications previously reserved for polyol esters and phosphate esters were discussed. These fluids exhibit excellent low-temperature properties, viscosity indices, newtonian behavior and are stable to mechano-degradation under the high shear rates. This new class of thickened water-glycol fluids exhibit superior fire resistance properties in the current Factory Mutual spray flammability and hot-channel tests. Pump performance tests showed that these fluids exhibit excellent wear resistance at high pressures under various use conditions. Based on these data, it is concluded that the high-performance thickened water-glycol hydraulic fluids are excellent candidates for providing greater fire resistance than typically achieved with phosphate ester and polyol ester fluids while at the same time exhibiting essentially equivalent wear properties.