Mechanical Seal Repair and Refurbishment
Mechanical seals are a critical component in many industrial applications where fluid containment is paramount. These seals work by maintaining a tight seal between two surfaces, allowing fluid to pass through while preventing leakage. Over time, however, mechanical seals can become damaged or worn, which can lead to a loss of containment, reduced performance, and even catastrophic failure. This is where mechanical seal repair and refurbishment come into play.
Mechanical seal repair and refurbishment involves the restoration of a mechanical seal to its original condition, thereby extending its lifespan and ensuring optimal performance. The process typically involves lapping or polishing the seal faces to create a perfectly flat surface with a high surface finish. This is accomplished through the use of specialised equipment, such as Kemet diamond lapping machines, and liquid diamond consumables.
Kemet's diamond lapping technology is well established and is used worldwide by major multi-national seal and valve manufacturers, as well as maintenance departments of oil and gas installations. The technology provides optimum flatness and surface finish, faster stock removal, faster polishing process, and is cleaner than conventional lapping. Kemet has been involved in seal and valve work for more than 60 years, and has the technical knowledge to process almost any seal material, including carbon, steel, stellite, ceramic, silicon carbide, and tungsten carbide. Kemet Diamond lapping can be used in the process of manufacturing of mechanical seals and reconditioning/repairing mechanical seals. The technique can also be used with pressure relief valve bodies, pressure relief caps, and slide valves.
To support mechanical seal repair and refurbishment, Kemet offers a wide range of diamond consumables and non-diamond abrasives specifically designed for mechanical seal lapping. In addition, Kemet offers a technical article on lapping and polishing of mechanical seals, which can be used as a resource for individuals seeking to improve their knowledge in this area.
Mechanical Seal Maintenance using Lapping and Polishing - Case Studies
The actions involved lapping three seal sizes on an open-face machine to improve parallelism. The goal was a surface finish of Rz < 1 (Ra < 0.12µm) and 2µm parallelism. Using a Kemet 24” lapping/polishing machine, a 24” Kemet Iron Lapping plate, Kemet Flatness gauge, 14-micron liquid diamond, and Co42 cleaning fluid, each seal was placed within a 24” control ring on a flat Kemet iron plate. The machine ran in 10-minute cycles, using type k diamond slurry. The process achieved the desired surface finish and demonstrated flatness within 1-3 microns.
After Polishing, flatness result
The actions undertaken involved the lapping and polishing of various seals composed of different materials. In the first stage of the process, lapping is performed using a Kemet 15" lapping/polishing machine, a Kemet PR3 lapping plate and Type K std abrasive. Each seal is centrally positioned within a control ring on a flat Kemet PR3 lapping plate on the Kemet 15 machine. A Dycem faced hand weight is placed on top to apply pressure and act as a fixture. The machine is cycled with Type K Liquid Diamond until the seal face is cleaned. The part is then removed and cleaned with CO42 cleaning fluid.
In the second stage, polishing is carried out using the same Kemet 15" lapping/polishing machine, an ASFL polishing cloth, a plastic-faced control ring, Type K std abrasive. The cleaned seal face is positioned within a plastic-faced control ring on an ASFL polishing cloth, and a Dycem faced hand weight is applied on top. The machine is cycled with Type K Liquid Diamond. Subsequently, the parts are removed and cleaned with CO42 cleaning fluid.