At a chemical plant in Limburg there are a number of KSB centrifugal pumps with start / stop function for a tank farm. The seals fail very frequently.
The MTBR is 4 to 5 months. They are outside installed pumps with a double seal and barrier fluid system.
The temperature must remain above 60ºC otherwise crystals form in the liquid. There are very fine solid particles in the liquid.
The Sellon solution
We have chosen the Chesterton S20 seal
With the face combination SIC / SIC-SIC / CB viton.
Barrier fluid pressure 3.5 bar.
Since this is a tandem seal, it is possible to opt for lower or higher pressure in the secondary system.
As a result, we are not dependent on the medium to be pumped and we are assured that there is always clean fluid between the running faces.