We have had a couple of internal 150 mesh screen failures in our Main Turbine Oil Tank Strainer Baskets. These baskets filter the return oil from our Turbine catching all the large debris. I have a couple of questions for you all.

1) Have you ever seen this happen before?
2) What size screen mesh is inside your baskets? Ours is 150 mesh.
3) Who repairs your baskets?
4) Do you have any suggestions?
I have tried to attached a picture.
Thanks,

strainer_bask4.jpg (468 Kb, 551 downloads) Stainer Basket

This is a problem I feel should be taken up with the strainer manufacturer. From the photo it appears your strainer fabric rotted away. Large pieces are torn away or missing with some evidence of corrosion (red/brown splotches). What is the mesh fabric made of? Have you had any contamination problems with your oil (water/chemical) that could have attacked the fabric? If you have these baskets relined ensure the fabric is compatable with your turbine oil. Interesting problem. Good luck.

The 150 mesh is Stainless Steel. The corrison you are seeing is actually where the 150 mesh was welded to the outside screen. I feel we should have something like 100 mesh screen. What size mesh does your plant use?

The plant I am in now does not have a turbine oil system and I do not recall what was in the past plants as far as mesh size. I have only seen suction strainers and not had experience with return oil strainers. I have seen systems that have had just the perferated baskets without the fabric as the suction strainers duty is to protect the pump from large particles which could damage it. So the mesh size is less critical than what your online filtration and ofline filtration/purification system is. Do you have supply filters and some form of ofline oil conditioning such as a centrifuge or vacuum dehydration system? At any rate this strainer should be repaired and I see no reason why a 100 mesh fabric couldn't be used. There may be other options as to composition of the fabric such as a cloth of some type since it would be fully supported by the basket. Good luck.

I have used 2 half baskets. One of 150 mesh and one of 100 mesh. We bolted the screen instead of welding it and we uses 2 layers of mesh on each basket with a supporting piece of large, but stronger, screen inbetween the two layers.

MR. Anderson,

Sargent & Lundy is preparing a maintenance guide on the turbine-generator lubrication system maintenance for EPRI. We would like to include the picture of the failed strainer basket you posted in the guide with proper acknowledgements. We need your company's permission to include the photograph with your permission. We would appreciate you granting us the permission. I can be reached at (312) 269-2755. Thank you and looking forward for your permission.

Bala Gogineni
Manager
Operations and Maintenance
Sargent & Lundy
55 East Monroe
Chicago, IL 60603
email address: balakrishna.r.gogineni@sargentlundy.com
Phone No. (312) 269-2755
Fax No. (312) 269-1847

quote:

Originally posted by dcanderson:
We have had a couple of internal 150 mesh screen failures in our Main Turbine Oil Tank Strainer Baskets.

How many strainers do you have and how are they plumbed? What is your return flow rate. How long have the strainers been in service?

quote:

These baskets filter the return oil from our Turbine catching all the large debris. I have a couple of questions for you all.

Were you coming off of an outage or turbine oil flush when the mesh lining gave way?

quote:

1) Have you ever seen this happen before?

Yes I have seen this before. Largely do to the lack of a quality weld and or design of the basket.

quote:

2) What size screen mesh is inside your baskets? Ours is 150 mesh.

Was part of an Siemens IP Turbine upgrade at a fossil plant and they used 150 screens during their 24 hour flush cycle prior to going back on line. However the user has off line TOC equipment in service so general cleanliness is good. ISO 15/13/11 [c]

quote:

3) Who repairs your baskets?

You're best bet is to find a good fabricator who specifically understands your application needs and can apply that to their fabrication methods. I have had several old PLENTY style baskets relined by a local fab shop with great success. PM me for more details.

quote:

4) Do you have any suggestions?

What is the current cleanliness level of your turbine oil?

We use both 100 and 150 mesh in our strainers. The initial run after coming out of an outage is with the bigger mesh and after we get to where we can run for several hours without filling a strainer we drop to the finer mesh. We have a problem with crap(for lack of a better term) in our system. We have to replace the kidney loop filters on a regular basis until the system gets cleaned up. After a turbine overspeed trip test we seem to rattle a ton of crap loose which can make us drop back to the larger mesh. We are planning to do a high pressure flush during our next outage.

Our maintenance crews change the mesh and maintain the baskets. We do not have the mesh welded, it is bolted in.