Type 7828 is part of the 7800 Vessel Seal Family. The 7800 family consists of heavy-duty, dual-pressurized, back-to-back, pusher cartridge seals designed for mixing and agitating equipment. This flexible seal family incorporates modular hardware to provide maximum interchangeability and is available in four different configurations (7828G, 7828GD, 7848W, 7848D), which are specified by the applied seal face technology. Type 7828 is characterized by the use of non-contacting, gas-lubricated seal faces with unique spiral groove technology developed and patented by John Crane. For details on the wet- and dry-running versions, please see product description of seal Type 7848.
Type 7828 is available in two variants. On the Type 7828G, both inboard and outboard primary rings have spiral grooves, and are therefore operating as non-contacting seals. Where reduced barrier gas consumption is desirable, the Type 7828GD, a hybrid seal that offers a combination of non-contacting gas seal inboard and contacting dry-running seal outboard, would be recommended. Advantages of gas-lubricated seal Type 7828 (G, GD) include the non-contacting, wear- and particle-free operation, the freedom from contamination by barrier liquid together with a cost-efficient, easy-to-install (gas) supply system. This makes these seals the perfect solution for high-end pharmaceutical applications.
The 7800 Vessel Seal family was originally developed for the North American market. Therefore all measurements follow imperial units and standard designs are available for inch-sized agitator shafts from 1.000″ to 5.000″. Adaptations to interim or metric sized shafts are available on request. The Type 7800 Series generally accommodates large amounts of radial runout. Therefore, and due to the specific non-contacting face design, the 7828 (G, GD) is able to work without integrated trust bearing. Nevertheless, a radial bearing option for additional shaft stability is available.