The BGMFL85 series mechanical seals offer a wide range of applications for gas-lubricated mechanical seals in high and low temperature environ-ment. It is suitable for liquid gas pumps, in the refinery and petrochemical industry, in tandem arrangement or as safety seal on the atmosphere side. The special design of the drive collar allows the installation of all kinds of secondary seals. The bellows are based on the proven lamella geometry but with reduced spring rate and are hydraulically balanced. There is no dynamic O-ring and hence no danger for hang-up problems. The U-grooves are placed in the stationary seat, V-grooves (dependent on direction of rotation) are possible