Sealing
Original rotating unions used the media pressure to maintain seal contact. Logic indicates that as pressure increases, so do the forces holding the seals together - more pressure = tighter, better sealing.
This is why they were called “pressure joints”.
However, more pressure on the rotating seal face also meant more friction, higher torque and more wear. The resulting service life was not satisfactory.
DEUBLIN was aware of the disadvantage and applied “Balanced Mechanical Seal Technology”, a decisive improvement.
This simply means the load or pressure on the seal faces is kept to a minimum regardless of media pressure, resulting in a freer turning union and in longer seal life.
Optimal balance ratio allows for a thin film of “lubricating” media between the seal faces.
In order to attain sealing in a non-pressurised system, the floating seal contact is maintained by the spring pressure.
Manufacturing
The entire DEUBLIN product range is manufactured at the cutting edge of technology from the very first drawing to the final production. Modern CNC machining centres transform highest quality materials into precision components. Cost-effective production is achieved by applying new technology and the most modern equipment.
Once assembled EVERY rotating union is dynamically pressure-tested for leakage as part of the final inspection procedure prior to despatch.
The core of a rotating union is the seal combination. Seal faces manufactured from tool steel, carbon graphite, bronze, ceramic, tungsten carbide or silicon carbide are micro-lapped to a surface finish of 0.025 RMS and an optical flatness of 2 light bands. To ensure the above specifications the near perfect flatness is tested under mono-chromatic light (refer to picture).
All DEUBLIN Rotating Unions are factory lubricated and tested, ready for installation. Unions not equipped with grease fittings are lubricated for the life of the union and require no further maintenance. Rotating unions, which are equipped with grease fittings, may require periodic lubrication to replace the grease which has dissipated. Overgreasing can be as damaging to the union as undergreasing, particularly in high-speed applications. Relubrication frequency and amounts of grease vary greatly depending on union size, operating temperature, rotation speed, moisture, etc.
When relubricating DEUBLIN Rotating Unions, use Kluber Lubrication’s Petamo GHY 133N. Only low-pressure grease equipment should be used to prevent damage to the bearings and seals. This is a general guide that should be used judiciously. The user must make adjustments as experience dictates. For more specific information, contact your local lubricant supplier.