SAE standards for Flushing activities
In order to obtain an effective flushing operation,it isnecessary to refer to the flow capacity and the Reynolds number. In order to achieve a proper flushing activity, the turbulent flow of the fluid is identified according to temperature, oil viscosity and size of the flushing pipe. It is necessary to carry out the flushing using a certain flow rate of the fluid in order to determine the required level of cleanliness.
An example of flushing carried out by the OilSafe service that complies with the standard required as well as the identification of the Reynolds number:
Oil heating: minimum temperature 60°-65° as specified in standard ASTM D 6439-05, up to a maximum di 70°-75°;
Turbulent flow flushing with the correct Reynolds number depending on the internal diameter and cross-section of the pipe and according to the speed l/min required by the customer. In case of the presence of flexible hoses, it is recommended not to exceed a Reynolds number of 9000. As for rigid pipes, a speed higher than a Reynolds number of 11.000-12.000 is advisable.
Minimum flushing required by the customer for each pipe: 1 hour. Verification of the result using PALL equipment (internal OilSafetest laboratory instrument - PALL PCM 400 used to carry out on-site analyses after each flushing operation, with parameters that can be viewed on a display screen).
Subsequently, a test is carried out and then the flushing is continued for another 4-6 hours. Therefore, the minimum time required for flushing is approximately 8 hours, as specified in the OilSafe calculation.
A table showing the calculation of the proper Reynolds number in accordance with technical specifications is shown below:
The “flow capacity” table shown below represents the calculation of the Reynolds number, considering key parameters such as the fluid flow rate, the speed and pipe diameter, so that the flushing operation can be effective.