Frequent Pump (Mechanical Seal) Failure

Dear Mr.

I like to advice you to use for this services a double mecanical seal with a seal pot filled with oil.

Please reply if you need more relation

Best regards

Aurel Mares

Deputy Mechanical Plant Coordinator

S. C. Petrotel-Lukoil S. A.

Phone: 0040 727 377 185

Fax: 0040 244 512 031

E-mail: AMares@Petrotel.LUKoil.com

I would recommend taking a look at the Kolsterising treatment process for the mechanical seals. Or I would insist that your supplier take a look.

The process can produce a surface hardness of 70 HRc of 300 series stainless (as well as some othe materials) for components that suffer from wear and galling related issues without dimensional change or loss of corrosion resistance.

I know it has been an effective treatment for certain pump components and may be worth a look.

www.kolsterising.com

Does a mechanical seal " have " to be used? If not then there alternatives, including the "old" packed gland seal.

Best solution is to remove the sand prior to pumping it. try modifying the cyclone cleaner so that the sludge feeds out the edge continuously, a centrifical filter is best for this process.

Meanwhile, by polishing either the impellor or backing plate and placing a wad of felt around the seal, this acts like a brush to keep the sand out. it must touch the seal so the fluid will keep it cool, a heatsink around the stationary side is often needed too.

I've used the above in all sorts of concrete cutting and drilling equipment with great success. As they contain diamond chips they are far worse than sand.

Quite.

Get rid of the sand first.

Emmanuel, please indicate what sort of API seal plan you have, the type of seal and materials as well as the failure mechanism/mode of the seal. Photographs of the failed seal components would also be useful.

Speak to a specialist repair company for experienced views on your best solution. Nothing can beat experience for a problem such as this. Try http://www.nicolandandrew.co.uk/ . If a designed solution is required, then a small well filtered bleed could be used to create a pressure balance across the problem seal.

Mech'l Seal Especialist needs to investigate the service conditions as well as the pumped-fluid.

please give more details about the following:

1. type of mechanical seal

2. fluid discharge pressure, psig/bar g

3. fluid temperature

4. fluid viscosity

5. shafting conditions after mech'l seal is damaged

6. how long the mech'l seal can stand before it breakdown?

Check if API 618 Plan 32 is suitable...

Basically Plan 32 recommends, "Flesh from external source with a clean compatible liquid."

If 'a clean compatible liquid' is available, this plan is much cheaper than 'double seal arrangement'.

Sorry for the erroneous indication:

It should be API-680 not API-618.

Plan 32 is as below:

Please discuss if a clean, external source is not available. There are other options.

Emmanuel,You really need a slurry centrifugal pump for this application. The mechanical seal failures you are experiencing would be alleviated by what a slurry pump offers:1. larger diameter shaft, with shorter impeller over hang. This means that the shaft deflects much less, resulting in longer mech seal life 2. a robust double mechanical slurry mech seal. Also a slurry pump offers specialized materials like high chrome hard iron, which is harder and thicker for superior abrasion resistance of wear parts. Metso Minerals can help you. Where on the globe are you located ? Send me an email at carmine.cacace@metso.com Regards,Carmine Cacace, P.Eng.Slurry Pumps Manager - CanadaCheck out:www.metsominerals.com/pumps

Consolidated Rutile Limited are a company situated at North Stradbroke Island, Queensland Australia. They pump sandy sea water to extract rutile, and have decades of exsperiance, there maintaince department may be able to help.

www.consrutile.com.au

phone 07 3409 6800

Sealing, particularly of mechanical type seals is a subject of its own, and the application and its maintainance is also just as important. Centrifugal Pumps for crude oil application may also have the heating requirement to reduce its viscousity, and correspondingly cooling jacket on pump itself etc. (assuming).

as there is sand count with the flow of crude oil, the seal will require a separate clean and with proper PH water supply for lubricating the mating seal faces and carry away the heat generated while the pump running. the API 610 specification for chemical centrifugal pumps, gives guidline for the type of sealing arrangement etc. to go for. Important thing to remember is, to control mating face running temperature, cleanliness of mating faces, the correct combination of rotating seal face material and the stationary face material etc. In addition to this, the fitting of seal assembly in the pump stuffing box is equally important, followed by regular supervision of running pumps periodically to assess the condition of seal faces, leakage amount from sealing faces etc. I agree with the other contributors, for their input on the subject matter.

My experience with Chemical Pumps and their sealing applications has led me to believe that there is not a solution that fits all the pump sealing problems, but for each pump, it is unique and different because of varients are numerous. here the experience counts a lot and the systematic analysis of problem that needs to be done, understood and corrective action needs to be taken on a continous basis, until the problem is resolved..