BS ISO 23309:2016 pdf free

BS ISO 23309:2016 pdf free.Hydraulic fluid power systems一Assembled systems一Methods of cleaning lines by flushing
The main requirement for effectively removing particulate contamination from hydraulic lines is that the flushing fluid has turbulent flow. Turbulent fluid flow also ensures transportation of the particulate contaminants out of the system and to the filters. The system flushing parameters shall be selected such that the Reynolds number (Re) is greater than 4 000 for flushing the system effectually (see 8.2.2). If possible, flushing should be performed with a fluid with a Re value greater than exists in the system during actual operation at normal service viscosity and maximum flow rate. Experience has shown that the flow rate during flushing should be more than two times the system’s expected flow rate,as long as adequate turbulence is maintained.
NOTE If the flushing is done with a fluid flowing with a Re number less than 4 000, there could be sections of laminar flow within the lines.
If there is difficulty in obtaining a Re greater than 4 000, the Re should be raised by either reducing the viscosity or increasing the flow rate. Reduction of viscosity is the preferred method. Viscosity can be reduced by increasing the temperature or by using a compatible flushing fluid with a lower viscosity.
If the fluid temperature is increased, the temperature rise shall be limited to ensure that the fluid properties or the components are not adversely affected. If a special flushing fluid is used, it shall be compatible with the intended system fluid. The preferred options are to use the system fluid for flushing or a lower viscosity grade of the same system fluid.
In a cold environment, the flushing fluid can suffer from heat loss. In such a case, in order to verify that Re is greater than 4 000, the temperature of the fluid shall be checked at the estimated coldest point of the system. Flushing shall only be accepted when the lowest temperature measured provides for Re greater than 4 000 (consult the manufacturer’s data for the viscosity and temperature of the relevant flushing fluid). Under very cold conditions, the system shall be insulated to keep the temperature above the minimum necessary to provide for Re greater than 4 000.BS ISO 23309 pdf download.