Manufacturer: John Crane
Heavy duty Dual cartridge Seals
The Safeseal Type SB2A is a dual cartridge seal. Its double balanced design ensures the reliability and longevity of the seal in the most demanding conditions. The Type SB2A seal is ideal for use with environmentally hazardous and abrasive fluids, most often used in pumps in pulp mills, minerals processing and other slurry duties up to 40% solids by weight and a solids hardness of 8 Mohs. The Type SB2A seal is widely used with other process equipment including agitators.
Several variants of the design available for different services:
Type SB2 - designed for DIN standard dimensions
Type SB2A PR - designed for ANSI standard dimensions, including integrated pumping device
Type SB2B - designed for big bore dimensions
Type SB2B PR - designed for big bore back plate dimensions
Type SB2S - designed for special dimensions, including metric sizes
Type SB2S PR - designed for special dimensions, including integrated pumping device
• The springs are located in the stationary body of the seal in the seal water (barrier fluid). The seal water washes the springs, preventing process chemical corrosion and reduces the risk of the springs becoming clogged. Shaft misalignment does not vibrate or wear out the O rings.
• PTFE slot rings replace the traditional O rings in places where they are exposed to the product, preventing sticking.
• Protected faces, the seal face carriers are driven by machined fits, preventing metal stress from distorting the face.
• Patented double balanced design allows the use of both pressurized and unpressurized seal water (barrier/buffer fluid) and prevents face overload.
• SB2 series seals will accept± 0.080"/± 2.0mm axial movement (shaft end play) during normal operation due to their piston design. Impeller adjustments do not affect face stress or spring strength.
PRESSURE LIMITSProcess pressure: 290 psi(g)/20 bar(g) Barrier fluid: 215 psi(g)/15 bar(g)
STANDARD MATERIALSSeal faces: SiC/Carbon or SiC/SiC O rings: PTFE, EPDM, Viton, FFKM Metals: AISI 329 and 316 standard, titanium, Hastelloy, UHB, 904, SAF 2507 for sea water applications Springs: Nimonic steel