Hydraulic fluid properties and its influence on system performance

Abstract: Hence hydraulic fluid is the medium of power transfer in hydraulic equipment, it is important to know the properties of hydraulic fluids and its influence on system performance. There are different types of fluids based on their availability, working purpose etc. So selection of fluid depends on the working conditions of the hydraulic equipment. So to select a fluid one has to be clear about the operating conditions of hydraulic equipment and this can be achieved by testing the equipment with different fluids and select the fluid that gives the best performance. To know about the properties (like Viscosity, operating temperature range) of fluids available there should be some standardisation of hydraulic fluids and one such type is ISO (International organization for standardization). Though there are many this is followed by most. By this standardization the fluid manufacturer can categorize the fluids and the user can easily select the fluid according to their requirement. The thesis work mainly deals with two parts. First part is giving a brief description of fluids based on ISO standards and standard test methods for hydraulic systems. The major or second part deals with finding the performance of six different types of fluids from four different manufacturers. Among them five fluids are environmentally acceptable hydraulic fluids and one is mineral oil based hydraulic fluid. The main task is to find the performance of this five environmentally acceptable hydraulic fluids comparing with standard mineral oil so that it will be useful for the equipment manufacturers to select a fluid for the system. The other main task of the thesis is to measure the pressure losses in long hoses which are used in forest machines. So a test plan was made to cover both the tasks, where the test method to find the losses in hose is one of the test method in finding the performances of the six fluids. The procedure about the tests are clearly explained in section 5.1. Among the five environmentally acceptable hydraulic fluids one is synthetic bio diesel and remaining four are synthetic ester based fluids and standard mineral oil is paraffin based. Because of the confidentiality the fluid names has been changed based on their viscosity as diesel oil (synthetic bio diesel), synth 32, synth e 32, synth es 32, synth 12 and mineral oil 46 (standard mineral oil). Synth e 32 and synth es 32 are the upgraded fluids of synth 32 fluid from same manufacturer.