DMSF solves reliability issues for Swedish company

With Fredrik Sternvad

A loss of flexibility and strength was causing seals on three boiler feed pumps at a Swedish energy plant to fail every year. AESSEAL’s range of DMSF™ double cartridge mechanical seals solved the problem, as Sweden’s technical sales manager Fredrik Sternvad explains.

Why were the boiler feed pumps losing flexibility and strength?

Competitor seal design did not provide enough circulation/cooling of the sealing water. Elastomers could not withstand the temperature generated and failed.

How difficult was repair work and what were the main problems?

It was difficult due to the placement of the pumps. These are bigger/heavier pumps stuck in a tight spot of the plant. Not too great lifting capabilities and pipework made it challenging. Not much room to work with.

How serious would the problem have become if a solution had not been found?

Losing seals now and then would has been a costly problem. Also losing a pump during winter time, when they are supposed to run all the time, would have meant that the other pumps would be run at a much higher capacity to make up the loss.

Was the installation of the DMSF an obvious solution? What made it an ideal replacement for the previous seals?

Yes, the design of the DMSF was a perfect match to solve the issue. The integrated pumping ring let the cool seal water run through the seal better and faster, cooling the seal better than the competition.

Was this an existing customer? Did they approach AESSEAL and how pleased were they with the work?

Yes, this was an existing customer. They approached us to solve their issue and they are very pleased.

How unusual is it for a seal to provide 12 years of uninterrupted service?

For us it’s not that common. The customer in this case has good knowledge and insight of their pumps’ performance and maintenance. They experience verry little process upset etc, prolonging the lives of the seals.

How much money will this have saved them and has AESSEAL received any more orders as a result?

I would say 300K Sek per pump over the period. Over the years we have received more orders after this success. They have also put these DMSFs as a stock item, claiming that they will never change out the make/model in these pumps.