Vessel and Agitator seals | Heavy-duty Cartridge Seal for Boiler Feed Circuit Applications


Features mechanical seal type 7828

  • California Residents: PROPOSITION 65 WARNING
  • Dual-pressurized cartridge seal for steel vessels
  • Back-to-back seal arrangement with balanced faces
  • Gas-lubricated (7828G) or contacting dry-running (7828GD) face options available
  • Reversed pressure capabilities inboard
  • Accommodates large amount of radial shaft run-out
  • Bearing option available
  • Debris well options available
  • Broad range of material option include
  • FDA or USP compliant materials
  • Standard design for inch-sized agitator shafts (1.000″ – 5.000″)
  • Special designs, interim or metric sizes and material options on request

Recommended Applications type 7828

  • Mixer and agitators
  • Other rotating equipment

About Mechanical seal type 7828

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.

Design Features mechanical seal type 7828

  • Patented grooved rotor allows equal lift in the presence of
    up to 0.125″ radial runout.
  • Patented primary ring shape responds under pressure,
    further enhancing very low speed face separation and liftoff.
  • Double cartridge uses common springs, allowing for selfadjustment to axial motion.
  • Optimized drive minimizes seal face to seal cartridge
    hardware interaction eliminating low speed hang-up.
  • Completely modular design, the universal vessel seal offers
    maximum application flexibility.

Operating range mechanical seal type 7828

  • Temperature Limits -40°F to 400°F/-40°C to 205°C
  • Pressure Limits Vacuum to 210 psi(g)/14.5 bar(g)
  • Speed Limits Dry: 400fpm/2m/s Wet: 5000fpm/25m/s
  • Size Limits 1″ to 5″

Product Description type 7828

The universal vessel seal (7800 Series) is a modular cartridge seal for use in a wide variety of mixing and agitating equipment and covering a broad application range.

The 7828G and 7828GD are heavy duty, gas-lubricated double seals designed for top entry mixers. The universal vessel seal uses modular hardware that provides maximum interchangeability. Four combinations of seal face technology provide the user with unmatched flexibility and value.

  • Type 7828G – Non-contacting, gas lubricated double seal uses dry nitrogen as a barrier gas and patented spiral groove technology to separate the primary seal  faces eliminating contact and creating a wear free environment, which insures 100% product purity and no batch contamination. Patented features enable the seal to maintain lift-off in the presence of extreme radial runout and even angular misalignment of the seal faces. The cartridge is
    reverse pressure balanced and will remain closed in the event that barrier gas pressure is lost. Materials of construction are FDA approved.
  • Type 7828GD – Where reduced barrier gas consumption is desirable, the 7828GD is a unique hybrid that offers a combination of non-contacting seal faces inboard and dry contacting faces outboard. Type 7828GD uses adaptive hardware that is identical to the 7828G.