Drive shaft seal for gear pump and method

US4737087A · kind A · utility

Assignee

• Barmag AG · DE

Inventor

• Siegfried Hertell · Radevormwald, DE

Key dates

• Filing date: Dec 10, 1985
• Grant date: Apr 12, 1988
• Expiry date: Dec 10, 2005

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16J15/40
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A seal for the drive shaft of a gear pump for polymeric materials dissolved in a fluid solvent is disclosed, and which is adapted to prevent the polymeric material from leaking and hardening on the drive shaft. The seal includes a pair of axially spaced apart annular packing seals surrounding the drive shaft so as to define an annular chamber, and means for supplying a pressurized shielding inert gas, such as nitrogen, into the annular chamber. An outlet line is connected to the lowest portion of the annular space and leads to an air tight container which also contains a shielding inert atmosphere, and such that any polymeric material which leaks along the drive shaft and enters the annular chamber remains in solution, and is withdrawn into the air tight container. A valve is also provided on the container for periodically draining the withdrawn polymeric material therefrom. The shielding inert atmosphere in the annular chamber and the container prevents the polymeric material from hardening, which can lead to the galling or scoring of the packing seals.