HSM Hydraulics provides an efficient Flushing service, as this is one of the oldest activity which is being performed among our scope of services. As an another important part of pre-commissioning activities the Flushing process is mandatory for hydraulic system before commissioning and start up of system / equipments to ensure the tubing and piping are debris free. Flushing is also carried out on existing operating system as a periodic maintenance to clear of unwanted deposits settled in the hydraulic system due to various factors during the normal operating conditions, which eventually restricts the flow and deteriorate the system efficiency.
What does lube oil flushing mean?
Lube oil system Flushing for any Hydraulic equipment;
Oil is one of the most important components in the hydraulic system. It is like blood for humans. Therefore, it must be taken care of by cleaning Lube oil system for rotating equipment to removal contaminants which can cause damage for Rotating equipment parts. These contaminants like (Welding derbies, Rust, Scales etc.…)
So, this activity is carried out to remove dirt from the system by loosening it from the inside of the system or by dissolving it in the flushing oil. Dirt which is picked up by the flushing oil will be caught in the filter installed in the return line and can be removed. Lube oil flushing is done by utilizing the " external system pumps with external filter." It requires the installation of bypasses (jumper hoses) around all critical components, such as cylinders and control valves, as well as the removal of all orifice plates and blinding of accumulators or any items that could be damaged by flushing. So orifices, probes and other flow restrictions must be removed for cleaning and flushing to obtain optimum velocities. All removed items shall be tagged and properly store for reinstallation. All the pressure gauges except lube oil pump discharge pressure gauge, pressure switches and instrument connections shall be isolated. All the PSVs shall be removed and blinded during the flushing.
Some Guidelines:
Turbulent flow for Oil must be achieved to perform good flushing, turbulent flow occurs at high Reynolds numbers and is dominated by inertial forces, which tend to produce chaotic eddies, vortices and other flow instabilities.
In layman's terms, the oil rapidly changes directions and bounces through the pipe's internals. This assists in breaking off material on the walls and top sides of the pipe's interior. If the right velocity is not achieved, the oil moves through in a laminar pattern (a straight line), following the path of least resistance and leaving behind material that can damage your system.
A Reynolds number of 4,000 is the minimum flow rate that can cause your fluid to become violent or "turbulent" inside the piping.
Flushing velocity and temperature: Flushing velocity and temperature should be as high as possible for the quick and effective flushing of the hydraulic system. Practical experience has shown that the temperature should be higher than the operating temperature if possible. In the case of mineral oils 60℃ is recommended and with water in oil emulsions and water-glycol 50℃ is recommended. The flow velocity should be at least twice that during normal operation of the installation and the flow should be in the turbulent range at all points. Cleanliness criteria for lube oil lines are guided by the following Codes and standards: 1-ISO 4406 : is analysis for oil to count solid particles in Oil 2-NAS 1638 : is also analysis for oil to count solid particles in Oil
