The following are some frequently asked questions (FAQ) that we often get about High Velocity Oil Flushing.
No, the size of the system is not as relevant as the amount of contamination or criticality of the system.
High particle count as well as type and size of debris (i.e. wear particles including but not limited to cutting, severe sliding, fatigue, ferrous, rust, black iron.) Also a membrane patch test can show your oils varnish saturation level, this could be a good indication of when to conduct a varnish removal flush or add Chevron Vartech.
A lot of our customers will make this a time based PM scheduled for the machines outage. Also can be based on the machines needs, this could be high particle count, plugging multiple onboard filters, excessive vibration or noise, plugged suction strainers, visible debris in sight glasses.
Your plant would have to weigh the cost of the HVOF vs. unplanned downtime and repair cost of equipment failure.
You would have to add a varnish removal chemical and ensure special precautions and tactics are taken with this procedure.
Rotary screw compressors are in a category all by themselves.
Flushing pressure are normally lower than normal operating pressures due to restrictions being removed (such as filters, flow orifices).
The length on the flush is always determined by the final qualification standards. These standards are supplied to us either from the OEM, customer, or end users IAW API614. The flushing time can vary based on many different things.
Flushing qualifications are always agreed upon before we start the flush. Industry standard normally dictates back to back one hour verification screens along with a particle count that meets the systems needs. Best practice is to clean the reservoir after the flush to ensure all debris has been removed.
HVOF is a mechanical means of cleaning, cleaning agents are a chemical way of cleaning.
We start by calculating a Reynolds number to anticipate the velocity. If we believe there is an issue with reaching the anticipated velocity, we do have ultrasonic flow meters that can be affixed to the piping system.
Standard solvents will destroy the oil. Also any kind of chemicals that are used need to be compatible with the metal type as well as all seals in the system.
We start by calculating a Reynolds number to anticipate the velocity. If we believe there is an issue with reaching the anticipated velocity, we do have ultrasonic flow meters that can be affixed to the piping system.
We always verify particle count prior to removing our equipment. We also recommend installing screens on start up to avoid any “reinstatement debris” being pushed to critical components.
Most manufacturers will supply a flushing procedure, if they do not we will create our own process and procedure following API614 for the final qualification of the flush.
We follow the piping manufactures specifications. Most large equipment uses 150 or 300 pound flanges. In the event that we are flushing a hydraulic or high pressure system we will bring in a high pressure flushing skid.
These machines are available for purchase on the market, however we have seen that it is not cost effective in the long run. The flushing skid is a piece of equipment that “hopefully” your plant will not have to use very often and the flushing process is very labor intensive and can pose high environment and safety risks if not conducted by an experienced crew.
When we use a flushing oil we use a very base oil with a low viscosity to increase the turbulence. This oil does not have any additives or chemicals that can damage the system. In the even that chemicals are used to remove varnish or other contaminates we have a few tactics that we use including:
Yes, the heat and the velocity of the flushing oil normally has the ability to move the sludge or contamination through the pipe into the oil reservoir or our filters. In the even that sludge does not break up with the hot oil we can add chemicals to the oil flush that will assist with breaking down the sludge.