Understanding High-Velocity Oil Flushing

Posted on: 2 January 2019

During construction, maintenance, repairs and commissioning, contaminants may find their way into the piping and tubing of hydraulic and lube oil systems of equipment. The contaminants can be in the form of dirt, dust, rags, welding slags, pipe scale, metal shavings and even water. When not removed, these contaminants shorten the life of rotating and hydraulic equipment. This is why high-velocity oil flushing (HVOF) is required.

What Is High-Velocity Oil Flushing?

HVOF is the process of removing the contaminants mentioned above. In addition to extending the life of rotating parts, HVOF keeps turbines, engines and compressors operating at their optimal condition and improves the overall reliability. The explanation behind high-velocity oil flushing is simple. During the normal flow of oils, the low velocity of the flow may encourage contaminants to accumulate on tubing or piping. A higher velocity is required to dislodge these contaminants.

When Is It Best to Carry Out Oil Flushing?

In the planning phase, during pre-commissioning, high-velocity oil flushing should be carried out. Areas to perform the procedure should include all piping circuits that consist of rundown tanks, coolers and spool pieces, among others.

Another time to carry out HVOF is during the maintenance of different equipment. Contaminants may not have entirely accumulated in the piping or tubing, and carrying out oil flushing may prevent severe accumulation. It is also considered a best practice to have a periodical maintenance and reliability program. HVOF should also be carried out when machines or equipment fails. Once replacement or repairs have been completed, carry out the process to restore and ensure cleanliness of piping.

You can also perform HVOF when you are changing or replacing oil. In this case, it is important to displace all of the old oil to reduce the chances of blending the different oils. You will require some sacrificial flushing oil.

What Can You Do to Maximise the Effectiveness of HVOF?

You can utilise a reverse-flow manifold to flush piping and tubing in both directions. This will help dislodge particles that prove difficult to remove. You can also have some heating and cooling cycles to help expand and contract pipes and tubing. This will also aid in dislodging some resistant particles.

Pipe vibrators and nitrogen gas can also be used. The vibrators are used during flushing so that as the pipe is shaking from the vibration, contaminants become loose and are carried away by the flow. Nitrogen gas needs to be used in low quantity. It creates a bubbling effect inside the piping, loosening stubborn particles.

For more information, contact an oil flushing service professional.