2,000 hours full contact in dry nitrogen

The tried and trusted elastomer-free, gas-lubricated EagleBurgmann PDGS mechanical seal was developed specifically for extreme requirements with high and low temperatures as well as high-pressure applications. Thanks to innovative design features it handles even the highest pressures and requirements without problems. High quality components such as polymer secondary sealing elements (U cups) make this a reliable universal seal in e.g. the oil/gas industry (LNG/PFSO ships), in pipelines, in refineries, or in the petrochemical industry.

In late 2015 this seal type underwent three months of testing and continuous operation at the EagleBurgmann test facility, as contracted by the important compressor manufacturer, leading in LNG applications. It was the first time that this compressor seal with a shaft diameter of 300 mm was tested for 2,000 hours in Turning operation. A rotational speed of 7min^-1 per minute with full sealing surface contact with dry nitrogen, and temporarily propane, put the seal through a grueling test. The DF technology with the hardest known material offers maximum resistance against abrasive particles in the process gas. At the end of the test the sealing surfaces showed no signs of impairment or destruction even though the sealing surfaces were constantly in running contact during Turning. Based on this outstanding result, the manufacturer granted its approval to install EagleBurgmann mechanical seals in its compressors. Seal faces are engineered for only a very limited period in Turning operation, as a rule. Longer Turning usually leads to increased wear and destruction of the sliding surfaces.

Added safety below the lift-off threshold - also for ratcheting - is provided by seal faces with this coating. The shaft here is rotated further by 45° at specific intervals, e.g. to avoid thermally induced deformations to the shaft. The sliding surfaces have full contact in this operating state as well.

The successful 2,000-hour test result clearly shows the high performance of this sealing type and the seal faces with DF technology. Several years ago, EagleBurgmann's innovation helped set a milestone in mechanical seal technology because these mechanical seals are characterized by their extreme hardness and wear-resistance, excellent thermal conductivity and greatest chemical resistance.

The pressure operating range of the seal generally covers 0 bar to 450 bar. Stable leakage rates and a safe operating behavior distinguish the PDGS in all operating states. When used in low temperatures, the specifically developed dynamic secondary seals exhibit an outstanding mobility. They satisfy all requirements such as automatic alignment, resistance to extrusion, and temperature and chemical resistance. These are properties which give the compressor seal, and thus the entire system, a high degree of operational safety and availability.

Technical features of the PDGS

• Greatest chemical resistance of the face materials in aggressive acids, alkaline solutions and bases
• High rigidity of gas film
• Optimized aerodynamic 3D gas grooves with self-cleaning effect
• Available in different materials for optimal chemical resistance, also with the EagleBurgmann DiamondFace technology
• Ready-to-fit unit

Operating limits

• Shaft diameter d_n = 29 ... 350 mm (1.14 " …13.98 ")
• Operating pressure p = 0 bar ... 450 bar (6,525 PSI)
• Operating temperature t = -170 °C ... +230 °C (-274 °F… +446 °F)
• Sliding velocity v_g = 0.6 ... 200 m/s (2… 656 ft/s)
• Turning = 0.15 m/sec.