Flushing Procedure Frequently Asked Questions

FAQ’s for Flushing Procedures

Below is a list of frequently asked questions we get from our customers. Our team of certified field technicians have provided answers and we are happy to answer any additional inquiries you may have that are not covered here. Contact Cogen Cleaning or call 1-832-715-9283.

1. How do you know or prove you are achieving the high velocity? Do you provide a flow meter? If so what is the flow meter type?

The velocity of each flush is based on a pre-generated Reynolds Number (Re). Piping diameter, fluid temperature, linear footage, piping schedule, and viscosity are factored to ensure proper turbulent flow is achieved in each section of piping. At a minimum, a Reynolds Number of >4000 will be generated. After the onsite system walk down, we will create a detailed process that ensures sufficient Reynolds numbers are achieved, and it will be submitted for your review beforehand.

2. Beta 1000; 1-micron rated filters; at 1-micron our lube oil additives will be stripped. Do you offer alternative filter ratings? Or, is this for the initial flush?

When dealing with turbine oil, the only additives you will typically have will be an Amine and Phenol package, along with a defoamant that is usually silicon. When dealing with these additives, they are considered “in-solution” additives and are less than 1um in size, and therefore, cannot be filtered out without leaching or hydrolysis taking place. Cgoen does, however, offer filtration in 1um, 3um, 6um, 12um and 25um sizes for flushing at Beta 1,000 efficiencies.

3. Are your 100-mesh SS screens placed on ALL lube oil delivery lines—i.e. all lines routing lube oil to equipment bearings—all lines requiring jumpers?

During our standard flushing process, all bearings and gearboxes will be bypassed. Depending on customer requirements, we can screen each jumper point, or we can screen the last connection point on the discharge header before the reservoir.

4. How are your SS screens made? Are the screens 100-mesh with a 40-mesh back-up screen sandwiched between two paper gaskets?

All screens are created by an outside vendor. They are custom-made per flange size requirements, and are structured like a thin slip blind with steel support backing to eliminate the chance of screen blowout. Mesh/micron is dependent on system requirements. Standard lube oil systems require 100-mesh, 140-micron, and seal oil systems can sometimes see specs as tight as 270-mesh, 53-micron.

5. Do you clean and reuse the SS screens?

Given the durable structure of the screens used by Cogen Cleaning, we reuse the screens until they begin to show visible signs of wear. At that point, they are sent back to our vendor and new screens are welded onto the backing.

6. How often are they checked?

Once any flush begins, differential pressure is closely monitored within the first minutes of beginning circulation. If we see any spike in pressure, we immediately perform a screen check. If no signs of back pressure are shown, we will run 30 minutes before pulling the first screens. At this point, a decision is made on how often checkpoints will be performed. It is primarily based on system cleanliness, and customer requirements.

7. What ISO particle count do you qualify as “clean” for a standard lube oil system ISO 32 lube oil operating at 100-PSI?

ISO standards are solely based on OEM standards and customer requirements. If these are not available, our internal standard for lube oil systems is 16/14/11. The primary goal when performing a high velocity hot oil flush is piping cleanliness, so we incorporate the use of API 614 visual standards alongside the ISO cleanliness specifications.

8. You mention you provide equipment jumpers to omit equipment bearings—are these custom-made-per-job or are they general purpose?

During the onsite system walk down, all required jumpers will be identified, and will be custom-made before arriving onsite for the project. This will also help eliminate unnecessary setup time during the initial phase.

9. If GP, how are the jumpers cleaned and kept clean?

All hoses are pressure tested and flushed until approved on oil cleanliness and piping cleanliness standards, in our Mobile, AL facility.

10. What are the jumpers made from—SS with flange ends, SS with threaded ends, or both?

We use a wide variety of jumper hoses. Depending on job requirements, we have SS steel braided flange ends, threaded ends (for size modifications) and rubber reinforced high-pressure hoses with threaded ends. All hoses used for equipment setup are SS steel braided flange connections.

11. Do you operate the lube oil flush around the clock? Is it ever unattended?

We provide manpower 24 hrs per day until project completion. We structure our schedule to ensure our equipment is monitored during day and night shifts, along with shift changes and lunch breaks.

12. What do you require from in-plant personnel—what level of interaction?

Our goal is to offer a full turnkey solution for our customers. After coordinating with our onsite contact once onsite, our goal is to provide everything needed to get the job done. One of our top priorities is good communication, and you will receive constant updates on our progress. We do require “approval” signatures for certain phases of the project to ensure your expectations are met. However, unless otherwise required, we will take care of staging, electrical setup to generator, pipe-fitting/millwright phases, circulation, and breakdown.

13. What are your lube systems power requirements?

Our power requirements are typically 480 3-Phase, 70 Amps–125 Amps.

14. Do you initially “muck-out” the lube oil reservoir prior to starting the flush?

Based on customer requirements, the system reservoir is cleaned by means of confined space entry. New or used flush fluid is then filtered back into the reservoir to begin the circulation phase.

15. Do you use your own lube oil or the plant’s?

Typically, the customer provides the flushing oil; however, if requested, we could supply, if agreed upon within the planning stages.

16. How much lube oil (normally/average) is required?

The lube oil flush is generally done with the in-service oil that is already in the reservoir. If new lubricant is being added to the reservoir for flushing, it is recommended that we have enough oil to fill all hard piping and our equipment with an addition of 200 gallons or less to maintain a positive head suction on our equipment to prevent aeration and cavitation of equipment during the flush.

17. Can you “cleanup” an existing lube system; cleanup by means of particulate filtration and water removal?

Yes, Cogen Cleaning offers custom side stream filtration for in-service units. We have a fleet of filter carts and dehydration units that will reduce particle count to better than 16/14/11 and water less than 100 ppm by Karl Fischer.

18. How do you verify lube oil cooler cleanliness—tube and shell side?

Tube and shell sides of the bundles can be inspected. Tube side (water side) will typically be flushed separate from the Shell side with an acid solution, if cleaning is needed. Shell side, can be inspected visually, or by means of screen checkpoint, to determine if any debris is still left in the system.

19. What make & model are your circulating pumps?

Cogen uses a variety of pumps (make and model). We use Custom Impeller Cut Centrifugal Pumps, Progressive Cavity and Positive Displacement Pumps, depending on the requirements of Reynolds number and head of the piping needed to effectively target a Reynolds number higher than 4,000 Reynolds. Major OEM’s used are Roper and Griswold Pumps.

20. Have you ever experienced your circulating pumps becoming too hot and requiring additional—external—cooling?

Cogen Cleaning has never ran into a situation where external cooling units were needed. Our Pumps and heater skids are thermally controlled by thermowells and thermostats to control oil temperature.

21. Is your lube oil circulating system composed entirely of stainless steel—if so, what grade of stainless?

No, lube oil circulating systems are composed mostly of carbon steel construction that have been coated. Yellow metals are not part of the circulating system, unless a ball valve is needed. These can be changed prior to any job containing fluids or chemicals that attack yellow metals like, nitrogen facilities with ammonia or EP lubricants. All butterfly or gate valves used have stainless face seals that are constructed using 316, 304 Monel or Hastelloy depending on fluids that are being flushed. Filter vessels are either constructed of 316, 316L or 304 SS and some are Carbon Steel Construction. Hoses are Stainless construction of 316 or Rubber.