Flushing of new pipe line

To clean new hydraulic or lube oil piping, if welded use a "pro" to do a pickling job with acid to clean out the rust and slag, then flush with high velocity (reynolds number high enough to cause turbulent flow) for normally 24 hours while hitting the pipes with a wooden mallet or steel hammer as applicable to make sure there are no pockets of crud.

Then if ready to put in the final oil flush with the final oil until it runs clean using a filter of 10 micron for lube or normal hydraulic or if variable control valves are in the system use a 3 micron filter.

If not ready to fill the system yet have the flush person put in a preservative (I prefer they not put in a water base preservative from past experience). When ready flush until the preservative is removed, it is best if you can let thye system stand full of the final oil after the pickling and flush rather then put in a preservative.

Economical is doing the very best job you can, it will pay not wiping a bearing or having a sticky hydraulic valve.

Yup. This is probably more than he was hping to get away with, but you are right on.

Prepare for the first flushing If applicable, check that the pipes are pickled.Clean the interior of the pipes and connect them correctly Confirm the action of each valve. Confirm the arrangement of each component Check and clean the sunction filter Install the temporary piping or turn terminal piping of bearing oil supply Install temporary strainer or wire net Check and clean the interior of oil reservoir Install a filter press. (if not fill-in filter be supplied) Prepare a wire net, to judge the cleanliness of the piping after flushing Fill the oil reservoir with the flushing oil for first flushing FIRST FLUSING Confirm the direction of rotation for each oil pump Operate the oil pump as a trial run. Check that there is no abnormality. Record the temperature. Hammer the piping for 30 minutes every 4 hours during operation Increase the oil temperature to become 50⁰C every 4 hours during operation Decrease the oil temperature to below 30⁰C every 4 hours during operation The pressure drop of the filter shal be no more than allowable value during operation Collect foreign matter every 8 hours (wire net in the reservoir) Repeat the above procedure for 3 days Check the pressure drop of the filter every 4 hours during operation. When the pressure drop of the filter is more than allowable value, clean the filter and replace the elements Install the wire net prepared for the judgment of cleanliness in each oil line Clean the filter and replace the filter elements with new ones, if necessary Replace the wire net for judgment with a new one Unit the first flushing passes the criteria of cleanliness, repeat the first flushing Prepare for the SECOND flushing Remove the flushing oil used for the first flushing Clean the interior of the oil reservoir Clean the filter and replace the filter elements with news ones, if necessary Fill the oil reservoir with the flushing oil for second flushing SECOND FLUSHING Repeat the second flushing for one day Collect foreign matter (wire net in reservoir) Check the pressure drop of the filter every 4 hours during operation.When the pressure drop of the filter is more than allowable value, clean the filter and replace the elements Install the wire net prepared for judgment of cleanliness in each oil line Clean the filter and replace the filter elements with new ones, if necessary Replace the wire net for judgment with a new one Unit the second flushing passes the criteria of cleanliness, repeat the second flushing Confirm the cleanliness Witness Remove all the temporary bypass piping and the wire net for judgment Restore all the piping to the service condition

Hi, you have already been offered basically excellent technical advise, some of which may seem OTT but as has been stated this is necessary to ensure extended system life.

The only thing I want to add is that to confirm that the system is to the required cleanliness level as per the manufacurers' requirements, you may want to get an analysis of the fluid. This can be done either by hiring a contamination kit and comparing a sample against a known slide, or simply send away to a laboratory. The latter may be more convenient and this could also be done on a regular (annual?) basis if the system is in constant use. Any breakdown in the components bearings etc will show up under analysis and determine whether component and or oil change is necessary.

It can become very costly not to flush correctly an hidraulic system. Once, and because of client wanting to speed up the startup (flush for 4 hours and that's ok, customer said), I saw an entire power unit consisting of 4 x 120hp x 310bar pumps sent to the garbage ( in the same week, all four pumps had to be changed). 7200€ each pump, plus another 8000€ for variable valves . Fault occorred 9 months after startup so warranty was still valid, but then the supplier asked for the signed report of flushing work. Client had none, because the engineer who made the flushing refused to sign it as "ok". Client had to pay 100%, and they still have problems of overheating and strange reactions in the system (faulty valves, never the same twice).

I am thankful to all who contributed to this forum. It is really very interesting to learn form the persons working in different fields & with lot of experience. I must admit that I am gaining lot of knowledge from this forum.

Once again thanks to everybody & I will certainly follow the instructions before commissioning of our new pipe line.