BS ISO 23309 pdf free download
BS ISO 23309-2020 pdf free download.Hydraulic fluid power systems — Assembled systems — Methods of cleaning lines by flushing.
4 Principle of flushing The purpose of flushing is to quickly remove surface particulate contamination to both limit the amount of damage to the components and to quickly achieve the RCL by the customer. This is achieved by circulating clean fluid under conditions of high fluid velocity, temperature and turbulence that are higher than that experienced in normal service and that will pick up the particles from the surfaces and transport them to a clean-up or flushing filter. The RCL is usually specified by the customer, but for the case where the RCL is not stated, Annex A provides selection guidelines. Component suppliers shall be able to specify the cleanliness level of their components. ISO/TR 10949 and ISO 18413 specify methods of evaluating and documenting the cleanliness level.
5 Flushing lines in a hydraulic system
5.1 Initial factors to consider Some factors to be considered for the achievement of a satisfactory cleanliness level for lines in a hydraulic system are:
a) the selection of components that have been cleaned in accordance with ISO/TR 10949;
b) the initial cleanliness of the fitted lines;
c) service or flushing fluid, which is cleaned to a level that, when added, is cleaner than the final flushing level, see 3.2; d) selection of suitable line-mounted filters that have a rating capable of achieving the RCL within an acceptable time period; e) the establishment of a high fluid velocity and turbulent flow regime that will pick up the particles and transport them to the filters. 5.2 System layout
5.2.1 Designers of hydraulic systems shall plan for system flushing in the design phase. Dead ends without circulation shall be avoided. If there is a risk of particulate contamination moving from the dead end to the rest of the system, then the dead end shall be capable of being flushed out.
5.2.2 Circuits should preferably be connected in series as the fluid velocity and Re of each single circuit can be calculated when the overall flow is given. Parallel connection of line sections however, is acceptable provided that turbulent flow can be achieved, maintained and monitored via flow meters.
5.2.3 Components that can prevent a high flow velocity being achieved or that can themselves be damaged by high velocities of particulate contamination shall be disconnected from the circuit or by-passed.
5.2.4 Sampling valves in accordance with ISO 4021 shall be provided at strategic locations.
5.2.5 The rating of any flushing filter shall be equal to or finer than the rating of any built-in filter elements, and any built-in filter shall be replaced for flushing, if required. The original specified and new filters may be reinstated after flushing. 5.2.6 Connectors and conductors shall be of uniform inside diameter to avoid trapping any particles for possible release later. They shall also be suitably sized to avoid large pressure losses. 5.3 Component cleanliness level Components and assemblies that are fitted into the system shall be at least as clean as the specified system cleanliness. Component suppliers should be able to give information regarding component cleanliness levels. NOTE The effect of component cleanliness on the whole system cleanliness level can be assessed using ISO/TR 10686. In order to estimate the component cleanliness level after flushing, in reciprocal approach, the final system flushing level could be redefined to the individual cleanliness of each component of the system. This requires knowledge of the whole system volume and each component of the system.
5.4 Anti-corrosion agents If the components contain anti-corrosion agents that are not compatible with the flushing or system fluid, the components shall be flushed before assembly using a degreasing agent that is compatible with the intended system fluid. The degreasing agent shall not affect component seals. The degreasing agent shall be of a suitable cleanliness, ideally to the RCL selected.
6 Treatment of lines
6.1 Preparation of lines during fabrication Tube or pipe to be used as a hydraulic line shall be deburred in accordance with procedures agreed between the manufacturer and the user. Tubes or pipes with scale or corrosion shall be treated in accordance with procedures agreed between the manufacturer and user.BS ISO 23309 pdf download.
