DiamondFaces® mechanical seals from EagleBurgmann deliver exceptional performance
14 November 2007
Burgmann Industries Wolfratshausen/Germany has introduced a revolutionary new diamond coating for mechanical seals, which offers excellent protection against wear during dry running, in applications with mixed friction and under exposure to abrasive media.
The specially developed crystalline diamond coating offers the same advantages as natural diamond and is suitable for applications in the oil and gas industries (eg multi-phase pumps), slurry applications, the chemical and pharmaceutical industries, and domestic applications (hot water).
The diamond coating on the seal face has a thickness of up to 8 µm. It is extremely hard, exceptionally long wearing and features outstanding heat conductivity, excellent chemical resistance and low friction, with optimal adhesion to the substrate being a decisive feature in this respect.
EagleBurgmann's DiamondFaces is a microcrystalline coating which is applied to the seal face using a chemical vapor deposition (CVD) process. The fundamental difference is the horizontal arrangement of the tungsten wires (which reach temperatures of 2,000C) in the vacuum oven; coatings up to 8µm thick can thus be applied without affecting the flatness of the sealing faces, and this is vital for proper functioning of the mechanical seal. The crystalline diamond forms a chemical bond with the silicon carbide facing, and as a result the adhesion of the coating exceeds all known practical application requirements.
SUCCESSFUL FIELD APPLICATION
In addition to field trials, some of the seals are already being used in tough continuous operation, for example in a Bornemann multiphase pump which is used to transport extremely abrasive media. The pump is being used for cost-effective production in Canada's large oil sand fields. Using the new SAGD process (Steam Assisted Gravity Drainage), steam is injected into the well to recover the crude oil or bitumen, and the pump has to handle a mixture of gas and solids. The single mechanical seal which had been used previously failed repeatedly after a short period of time. Now the same seal with a diamond coating delivers vastly improved performance and has been running without problem for four months.
