ISO 3968 pdf download

ISO 3968 pdf download.Hydraulic fluid power – Filters – Evaluation of differential pressu re vers us flow characteristics 1 Scope This International Standard specifies a procedure for evaluating differential pressure versus flow characteristics of hydraulic filters and constitutes a basis for agreement between the filter manufacturer and user. It also specifies a method for measurement of the differential pressure generated at different flow rates and viscosities by the relevant parts of a filter assembly, that is the housing, the filter element and any valves contained within the housing that are in the flow stream. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 1 21 9-1 , Fluid power systems and components – Graphic symbols and circuit diagrams – Part 7: Graphic symbols * IS0 3448, Industrial liquid lubricants – IS0 viscosity classification IS0 4021, Hydraulic fluid power – Particulate contamination analysis – Extraction of fluid samples from lines of an operating system IS0 4406, Hydraulic fluid power – Fluids – Method for coding the level of contamination by solid particles I S0 5598, Fluid power systems and components – Vocabulary I S0 1 6889, Hydraulic fluid power filters – Multi-pass method for evaluating filtration performance of a filter element 3 Terms and definitions For the purposes of this International Standard, the definitions given in IS0 5598 and the following apply. 3.1 filter rated flow rate flow rate recommended by the filter manufacturer for a specified kinematic viscosity 3.2 viscosity index empirical measure of the viscosity/temperature characteristics of a fluid NOTE The smaller the change in viscosity within a given temperature range, the higher the viscosity index. 5 Test equipment 5.1 General indications A suitable test rig consists of a pump, a reservoir, a clean-up filter, the filter under test and, if required, a heat exchanger, together with all the necessary equipment for measuring the pressure, the flow rate, the temperature and the fluid cleanliness level (see 6.5). Figure...