History and Position
•QB developed in 1969
•QBS developed in 1977
•QBQ developed in 1980
•QBB standardized in 2000
•QBQ LZ developed in 2005
•QB2B developed in 2015
•Designed from the start as a cartridge seal – Available as a component seal
•Flowserve’s most popular seal family
•Name derived from the spring end view

General duty engineered seal
•~19 basic seal parts for single seal
•~32 total parts for single cartridge seal






Balanced and unbalanced designs
•Seal balance is a design mechanism to reduce the hydraulic pressure pushing the seal faces together
•The black line represents the surface area where seal balance is calculated
•The green line represents the diameter that determines the % balance

Largely interchangeable with QB
•Unbalanced version of QB
– Limited to 10.4 barg (150 psig)
•Uses the same parts as QB except faces
•Utilizes unique rotating face
•Utilizes QB stationary face sized 0.250 above Q seal size

QBQ Seal - Designed for low emissions
• Increases balance ratio from 75% to 82%
– Reduces radial width (seal face area); higher unit loading
• Strongly desirable for applications with 0.45< SG <0.65
• May be used on applications up to 0.80 SG
– Minimize emissions
– Achieve interchangeability
• May be used above 0.80 SG
only on flashing fluids
• Primary Applications
– Non-flashing hydrocarbons
– Flashing hydrocarbons
– Default selection for most API 610 pumps

QBS Seal - Single coil spring variation
• Utilizes QB seal faces
• Unique spring holder – Slightly longer than QB

QBU Seal - Based on the QB seal
•Unique lube groove Precision Face Topography
•Designed specifically for hot water
•Designed to fit API 610 pumps or ASME B73.1 pumps and numerous
•100% compliant with API 682 design guidelines
•Available in Arrangement 1, single seals

QBU Seal - Applications
•Hot water
•Boiler feed water
•Water applications where cooling is desired, but not available

QBQ LZ Seal
QBQ with Wavy face
•Qualified for Category 2 and 3
•Designed to fit API 610 pumps
•100% Compliant with API 682 design guidelines
•Available in Arrangements 1 and 2 
Operating Window
• Pressure up to 51.7 bar (750 psi)
• Temperature -40 to 204°C (400°F)
• Shaft Sizes 13 to 140 mm (0.500 to 5.500 inch)
• Speed up to 23 m/s (75 fps)
• S.G. 0.4 to 0.6

QBQ LZ Seal - Laser-applied topography
•Features
– Can be retrofitted into a QBQ seal
– Precision face topography reduces seal
face generated heat
– Waves are self cleaning
– Pressure is built within the waves to
suppress flashing
•Primary Applications
– Light hydrocarbons operating on
low vapor pressure margin

QBB Seal - Pressurized from the ID
•Only used in the inner seal of Arrangement 3 dual pressurized seals
•Dynamic O-ring (Part #76) – 0.103 inch cross section QBB

QBB Seal - Double balance diameter
•Double balanced, can be pressurized from either direction
•Designed for Plan 53A or 53C

Pressure Pad Feature - Standard on QB2B seals
•Creates a support surface behind the stationary faces – Reduces pressure distortions



Performance Improvements
Compared to alternative sealing options, the QB2B offers:
•Reduced pressure distortion on seal faces
– Lower barrier fluid consumption rates
•Stronger seal face geometry
– High pressure capability
•Optimized barrier fluid circulation to outer and inner seal faces
– Extended barrier fluid life
– Suitable for higher process temperatures
•Fully standardized size range covers the entire range of API 610
– API 682 qualified
•Double balanced inner seal face with fully retained parts
– Capable of containing reverse pressurization upset events

QB2B Seal
API 682
•Designed to fit API 610 pumps
•100% Compliant with API 682 design guidelines
•Available in Arrangement 3
•API 682 Qualification Categories 1, 2, and 3
Operating Window
•Temperature -40 to 204°C (400°F)
•Seal Sizes 1.625 to 5.000 (0.125 increments; 28 sizes)
•Shaft Sizes 25.4 to 117.5 mm (1.000 to 4.625 inch)
•Speed up to 23 m/s (75 fps)

QB2B Seal - Materials of construction
• Rotating face
– Standard
 Antimony carbon
– Available
 Resin carbon
 Silicon Carbide (SiC)
 Diamond Coated SiC (K30)
• Stationary face
– Standard
 Silicon Carbide (SiC)
– Available
 Tungsten Carbide (WC)
 Diamond Coated SiC (K30)
• Elastomers
– Fluoroelastomer
– Perfluoroelastomer
• Metal Parts
– Standard
 316 Stainless steel
– Available
 Alloy C-276, Alloy 20,
Duplex, Super Duplex
• Springs
– Alloy C-276


QB Series - Available arrangements review
•Single
•Dual unpressurized with liquid buffer
•Dual unpressurized with containment seal
•Dual pressurized face-to-back
•Dual pressurized back-to-back

Summary - QB series seals cover a wide range of applications
•Several variations for specific applications
•Several configurations
•Several arrangements
•Extensive list of optional design features
•Over 100,000 existing applications
•Over 40 years of experience