API 610 BB3 Pump—“Interbearing, Horizontally Split Casing Pump”

The horizontal, mid-split, multistage pump complies with the latest edition of API 610 (ISO 13709) BB3 structural standard. This pump is an axially segmented, double-end-supported multistage design, primarily used for conveying clean liquids or liquids containing solid particles. It finds extensive application in oil extraction, petrochemicals, chemical processing, coal chemical engineering, pipeline transportation, seawater desalination, and boiler feedwater systems in power plants, among other fields. Additionally, it is suitable for use in high-pressure hydraulic energy recovery turbines in the chemical industry, as well as in lean-liquid and rich-liquid pumps for fertilizer production and ammonia synthesis units.

Core Performance Parameters

The maximum flow rate can reach 3,200 cubic meters per hour (14,000 U.S. gallons per minute).
The maximum service ceiling is 2,900 meters (9,500 feet).
The maximum working pressure can reach 300 bar (4,400 psi).
The maximum operating temperature can reach 200°C (400°F).
Outlet sizes range from 150 to 350 millimeters (3 to 14 inches).
Maximum speed can reach 6,000 rpm.

Product Features

Our Advantages

1. Casing: The pump adopts an axially split design with support points located close to the centerline. The inlet and outlet flanges are mounted directly on the pump casing, enabling convenient inspection and maintenance without the need to move the inlet or outlet piping. This design also simplifies rotor balancing, overhaul and installation, inspection and modification of the pump flow passages, and replacement of spare rotors.

2. Impellers: Manufactured using precision casting; each impeller is dynamically balanced and individually secured. The impellers are interference-fitted to one another, and a stepped-shaft design is employed at each stage to facilitate installation and maintenance. For sizes DN80 (discharge) and larger, a first-stage double-suction impeller may be provided to enhance cavitation resistance and improve the net positive suction head (NPSH).

3. Balance of Axial and Radial Forces: The impeller is arranged in a back-to-back symmetrical configuration, which enables self-balancing of axial forces; the intermediate bushing and throat bushing are used to balance the remaining axial forces, thereby reducing the load on the thrust bearing to a minimal level; furthermore, the volute is designed with an upper–lower symmetrical arrangement to minimize radial forces, thus decreasing shaft deformation and bearing loads.

4. Bearings and Lubrication: Depending on the shaft power and rotational speed, bearings may be selected as either oil-ring self-lubricating units or forced-lubrication units. The entire product series features isolated bearing seals, is equipped with carbon-steel bearing housings, and offers optional air-cooled or water-cooled bearing housings to meet specific application requirements.

5. Shaft Seals: The sealing system complies with API 682, 4th Edition, “Seal Systems for Centrifugal and Rotary Pumps,” and can be configured with a variety of seal, flush, and cooling schemes.

Capacity

Model Description

LCD display 800-150×6

LCD: Axially split, multistage pump with double-end support.
800: Rated flow rate of 800 cubic meters per hour
150: Single-stage head of 150 meters
6: Number of Stages
 

Structure Diagram

Performance Curve

1. Pump Casing: The casing adopts an axial-split design and is supported near the centerline. The inlet and outlet flanges are mounted on the pump casing. This configuration eliminates the need to move the inlet and outlet piping, thereby facilitating pump inspection and maintenance, simplifying rotor balancing and inspection, and streamlining the installation, repair, and modification of the pump flow passages as well as the replacement and modification of spare rotors.

2. Impellers: Precision casting is employed, with each impeller undergoing dynamic balancing verification and individual securing. The impellers are interference-fitted, and all stages utilize a stepped-shaft design to facilitate installation and maintenance. For sizes DN80 (at the outlet) and larger, single-stage double-suction impellers may be provided to enhance cavitation resistance and net positive suction head (NPSH).

3. Balance of Axial and Radial Forces: The impeller is arranged in a back-to-back symmetrical configuration, which enables self-balancing of axial forces; the intermediate bushing and throat bushing are used to balance the remaining axial forces, thereby reducing the load on the thrust bearing to a minimal level; furthermore, the volute is symmetrically arranged in the vertical direction to minimize radial forces, thus reducing shaft deformation and bearing loads.

4. Bearings and Lubrication: Depending on shaft power and rotational speed, bearings may be configured as oil-ring self-lubricating units or forced-lubrication units. The entire product line is equipped with shielded, isolated bearing seals and carbon-steel bearing housings. Bearing housings can be cooled by air or water, and cooling functionality is available for both methods.

5. Shaft Seals: The sealing system complies with API 682, 4th Edition, “Seal Systems for Centrifugal and Rotary Pumps,” and can be configured with a variety of seal, flush, and cooling schemes.

The full name of BB3 is “Between Bearing, Axially Split, Two Casing, Radially Impelled,” which translates to “two-end-supported, axially split, double-casing, radially impeller pump.” It can also be understood as a “drum-shaped outer casing, double-casing pump.”

The core design philosophy is to maximize the integrity and seal integrity of the pressure vessel while facilitating maintenance of the internal components. The specific structural breakdown is as follows:

BB3 Pump’s core product is the technologically mature MSD series of horizontal split-case multistage pumps. Designed in strict accordance with API 610 (ISO 13709) standards, these pumps are renowned for their long-term, stable operation under demanding conditions such as high pressure and high head, and have now been installed and put into service worldwide in excess of 10,000 units.

💡 Core Design Philosophy
Robust and reliable: The pump features a horizontal, open-type casing design that allows the pump cover to be opened directly without dismantling the inlet and outlet piping, facilitating inspection or replacement of internal components such as the rotor and greatly simplifying on-site maintenance.

Balance and Efficiency: The back-to-back impeller arrangement ingeniously balances the substantial axial thrust generated during operation, thereby reducing bearing loads. At the same time, its broad hydraulic performance envelope ensures that the pump consistently operates within the high-efficiency range.

Addressing Harsh Operating Conditions: Designed for a target service life of 20 years with an availability exceeding 98%, this solution is specifically engineered for critical processes that require long-term, continuous operation without downtime.

📊 Key Technical Parameters
The following is a summary of the core technical specifications for Sulzer’s MSD series (BB3 type) pumps:

Additional Notes on the Typical Range/Values of Parameter Items
The maximum flow rate can reach 3,200 cubic meters per hour (14,000 U.S. gallons per minute).
The maximum service ceiling is 2,900 meters (9,500 feet).
The maximum pressure can reach 300 bar (4,400 psi).
The maximum applicable temperature is 205°C/400°F; some data indicate that the upper limit is 200°C.
Outlet sizes range from 150 mm to 350 mm (3 to 14 inches).
Maximum speed can reach 6,000 rpm.
Flange pressure ratings may be selected according to engineering requirements as 600#, 900#, or 1500# (pressure class).
This level can be customized as needed (e.g., up to 8 levels). In practical applications, it is typically configured with 8 levels.
🛠️ Typical Application Scenarios
Due to their outstanding high-pressure performance, MSD pumps are widely used in the following fields:

Oil and Natural Gas: Long-Distance Pipelines, LPG Pipelines, Crude Oil Transportation.

Power industry: boiler feedwater systems in thermal power plants and nuclear power stations.

Energy extraction: water injection and carbon dioxide injection in oilfields to enhance oil recovery.

Water treatment: seawater desalination, reverse osmosis, high-pressure water supply, and mine drainage.

🔧 Key Structures and Materials
Pump casing and impellers: The first-stage impeller typically features a double-suction design, which effectively reduces the net positive suction head required and enhances suction performance; subsequent stages employ single-suction impellers, collectively delivering high-pressure output.

Material selection is highly flexible, enabling the pump to meet corrosion and wear requirements for various service media. For example, the pump casing can be made from carbon steel, low-alloy steel, or duplex stainless steel; the impeller and shaft are typically fabricated from high-strength stainless steel and equipped with replaceable shaft sleeves to protect the main shaft.

Bearings and Seals: Equipped with heavy-duty sleeve bearings or tilting-pad bearings to ensure rotor stability at high speeds. The sealing system fully complies with API standards and can be configured with a variety of flushing and sealing schemes.

Are you selecting a pump for a specific application, such as boiler feedwater or pipeline conveyance? If you can provide the flow rate, head, and fluid type, I can help determine whether an MSD pump is suitable or compare it with other pump types, such as the BB5.

Primarily used in oil extraction, petrochemical, and chemical industries.
Coal chemical industry, pipeline transportation, seawater desalination, power plants, and others
It can also be used for coal chemical pumps and low-quality methanol transfer pumps.
High-pressure hydraulic energy recovery turbine, fertilizer,
Lean solvent pumps and rich solvent pumps in the ammonia synthesis unit, among others.
Typical operating conditions are applied in high-pressure applications such as power plant boiler feedwater, steelmaking coking and phosphorus removal, oilfield water injection, and offshore platforms.

Flow rate: approximately 2,500 cubic meters per hour
Altitude: approximately 1,200 meters
Rotational speed: 2,950–3,600 rpm
Design pressure: approximately 25 MPa
Operating temperature: -80ºC to 200ºC

Structural Features and Composition
1. Double-walled shell and outer cylinder: a cylindrical pressure vessel manufactured by integral forging or die forging, with both ends sealed and equipped with heads. This is the primary pressure-bearing component, capable of withstanding the full system pressure, and it features no axial split flanges, thereby completely eliminating the risk of high-pressure leakage.
Internal pump core: comprising all wet-end components such as the impeller, diffuser, and pump cover, which are assembled as a single removable unit and installed within the outer casing.
2. Axial Disassembly and the “Core Assembly” • Maintenance Advantages: During maintenance, simply remove the end covers at both ends to extract the entire “pump core” or “core assembly” axially from one end, eliminating the need to disassemble the inlet and outlet piping or the motor. This enables exceptionally convenient and rapid maintenance.
3. Support and Bearings • Two-End Support: The pump shaft is supported by independent bearing housings at both ends of the pump, providing excellent operational stability and making it suitable for high-speed, high-power applications.
Heavy-duty bearings: A combination of high-capacity radial bearings and thrust bearings is employed.
4. Sealing System • Typically equipped with a high-performance double-end mechanical seal system compliant with API 682 to seal the high-pressure process fluid within the pump.
🏭 Main application industries and operating conditions of the BB3 pump
The BB3 pump is specifically designed for the most critical, demanding high-pressure, high-temperature, and high-risk operating conditions in the process industry, thanks to its exceptionally high pressure rating, outstanding operational reliability, and convenient maintenance.

Why is it necessary to use BB3-type pumps in typical operating conditions and piping sections within industrial applications?
High-pressure feed pumps for petroleum refining, hydrocracking, and hydrotreating units
High-pressure boiler feedwater pump (BB5 type is commonly used, but BB3 type is also suitable)
Safety of high-pressure liquid transfer pumps: The integral external cylinder is capable of safely withstanding system pressures of up to 20 MPa or even higher, with no risk of large-flange leakage.
Thermal shock resistance: The double-shell design effectively accommodates rapid temperature fluctuations, preventing deformation caused by thermal stress.
Quench Oil Pump and Quench Water Pump for Petrochemical Ethylene Units
• Ultra-high-pressure reactor feed pump for polyethylene/polypropylene plants
Reliability of the high-pressure liquid pumps in the aromatics unit: Their design ensures fault-free operation of critical process sections over several years of continuous service.
Maintainability: In the event of a failure, “core components” can be quickly disassembled and replaced, significantly reducing downtime.
Wear resistance of high-pressure differential liquid pumps for coal chemical processing, coal liquefaction, and coal-to-hydrogen plants: These pumps can be designed to handle high-pressure media containing small amounts of solid particles.
Other Process Industries • Offshore Platform Injection Pumps
High-temperature hot-water pumps for geothermal applications operate under harsh conditions, requiring simultaneous performance under multiple extreme conditions, including high pressure, high temperature, and severe corrosivity.

Selection and Comparison
BB3 must be selected in the following situations: when system pressure is extremely high (typically exceeding Class 600), or when the process fluid poses an exceptionally high level of hazard (high temperature, high pressure, flammable, explosive, or toxic), and when online rapid maintenance is required while ensuring zero-leakage risk. In such cases, BB3 is the optimal choice.

Comparison of the main alternative options:

BB1 (axially split horizontal pump): Suitable for medium- and low-pressure service. It is equipped with a large, open-type flange, which poses a leakage risk under high pressure and requires pipeline disassembly for maintenance.

BB2 (radially split multistage pump): Suitable for applications requiring high head but relatively low pressure (e.g., boiler feedwater pumps). Its maintenance and servicing are more complex than those of the BB3.

BB5 (Radially Split Double-Casing Pump): Similar to the BB3, the BB5 is also a double-casing pump; however, it features a radially split design. It is suitable for ultra-high-pressure and ultra-high-head applications, such as oilfield water-injection pumps and high-pressure reverse-osmosis seawater-desalination pumps. Nevertheless, because maintenance requires dismantling heavy casing bolts, its service speed is lower than that of the BB3’s pull-out-core maintenance configuration.

Conclusion: API 610 BB3 pumps are core, mission-critical equipment in the process industry, embodying an optimal balance of safety, reliability, and maintainability. Although their initial capital investment is relatively high, this substantial upfront cost is entirely justified and indispensable for ensuring the safe operation of the entire plant and for preventing the enormous financial losses associated with unplanned shutdowns.

The MSD series comprises double-casing, horizontally split multistage centrifugal pumps designed in accordance with API 610 (ISO 13709). These pumps are specifically engineered for demanding operating conditions and are capable of continuous operation under high-pressure, high-flow-rate conditions.

The following is a detailed analysis of its structural characteristics and application industries.

🔧 Core Structural Features
The structural design of the BB3 pump reflects careful consideration of high-pressure safety, stable operation, and convenient maintenance in every aspect:

Designed in accordance with international standards: The design strictly adheres to API 610 (ISO 13709), ensuring reliable operational performance and extended service life under harsh operating conditions.

Double-shell structure: This design features an inner cylinder and an outer pressure-bearing shell, enabling the pump to withstand higher system pressures and effectively preventing leaks of high-risk process fluids, thereby ensuring a high level of safety.

Horizontal Split-Case Design: The pump casing is split horizontally, facilitating easy disassembly. During maintenance, the inlet and outlet pipelines and the motor do not need to be moved; the pump cover can be quickly removed to inspect or replace rotor components, significantly reducing repair time.

Optimized hydraulic and balancing design:

Symmetrical Impeller Design for Axial Force Balance: By arranging the impellers in a symmetrical configuration, the substantial axial thrust generated during operation can be effectively balanced, thereby reducing lubrication system costs in most applications.

Double-suction first-stage impeller: In large pumps, the first-stage impeller is designed with a double-suction configuration, which effectively reduces the net positive suction head required and prevents pump damage caused by cavitation.

Industry-leading hydraulic performance: Its hydraulic model has been extensively validated, ensuring the pump maintains high efficiency across the entire operating range.

🏭 Main Application Industries
Owing to their high pressure, high efficiency, and reliability, Sulzer’s BB3 pumps are widely used in the following critical industrial sectors:

Oil and Gas: This is one of the primary application areas for BB3-type pumps. Globally, more than 10,000 MSD-type pumps have already been deployed in such operating conditions. Specifically, these include:

Oil pipelines: provide the driving force for long-distance pipeline transportation of crude oil.

Oilfield water injection: injecting high-pressure water into the reservoir to enhance oil recovery (EOR).

Flow Assurance: Used in deepwater oilfields for dead-oil circulation or hot-oil circulation to prevent pipeline blockage at low temperatures and ensure smooth production operations.

Petrochemicals and Refining:

Boiler Feed Pumps: In refineries and chemical plants, these pumps are used to continuously supply water to high-pressure steam boilers. A case study from a refinery in Argentina demonstrates that a Sulzer BB3 pump, which had been in service for more than 40 years, could be returned to operation after undergoing professional overhaul by Sulzer, thereby fully highlighting the durability and maintainability of its design.

Energy and Electricity:

Nuclear power services: Their reliability is sufficient to meet the safety-related service requirements of nuclear power plants.

Conventional power: used in the boiler feedwater system of thermal power plants.

Offshore production platform:

Seawater Treatment: For seawater desalination applications—such as reverse osmosis—in floating production storage and offloading (FPSO) units and fixed platforms that require high pressures, BB3 pumps are the ideal choice.

The pump’s stability and ease of maintenance are key reasons for its widespread adoption. If you are currently engaged in a specific selection process or would like to understand the main differences between this pump and comparable BB5 (bellows-type) pumps in terms of application, please let me know, and I will conduct a tailored analysis for you.
Flowserve’s API 610 BB3–compliant pump products include the DMX series (along with its derivative models, such as the DMXH for specific high-pressure applications and the DMX-RO for seawater desalination). Similar to Sulzer’s BB3 design philosophy, the DMX series is also a workhorse unit engineered for high-reliability operation under high-pressure and high-flow conditions.

The following is a detailed analysis of its structural characteristics and application industries.

🔧 Core Structural Features
The structural design of Flowserve DMX pumps is likewise centered on the core values of high-pressure safety, operational stability, and ease of maintenance:

Complies with International Standards: Designed in strict accordance with API 610 (ISO 13709) BB3 standards to ensure equipment reliability under harsh operating conditions.

Single-casing, horizontally split design: the pump casing is split horizontally, with the suction and discharge ports integrally cast into the lower half of the casing. Consequently, during maintenance, there is no need to move the inlet and outlet piping; the pump cover can be directly removed for inspection or rotor replacement, making maintenance exceptionally convenient.

Optimized hydraulic and balancing design:

Dual-volute design: The dual-volute configuration effectively balances the radial forces generated during pump operation across a wide flow range, thereby reducing vibration.

Back-to-back impeller arrangement: By arranging the impellers symmetrically (back to back), most of the axial forces are automatically balanced, thereby extending bearing life.

Optional double-suction first-stage impeller: To meet varying NPSH requirements, the first-stage impeller can be designed with either a single-suction or double-suction configuration featuring a large inlet diameter, thereby effectively preventing cavitation.

Robust Rotor and Bearing System: The rotor is mounted on a large-diameter main shaft, with the bearing span minimized to the greatest extent possible, thereby reducing shaft deflection under non-peak operating conditions. In addition, a variety of bearing configurations are available—such as ball bearings, plain bearings, and Kingsbury tilting-pad thrust bearings—to accommodate diverse load and operational requirements.

Materials for Harsh Operating Conditions: A wide range of material options is available, including carbon steel, 12% chromium steel, austenitic and duplex stainless steels, and even Monel alloy, to withstand corrosive or highly corrosive media.

📊 Key Performance Parameters
The Flowserve DMX series pumps offer an exceptionally broad performance range, with the following key operating parameters:

Supplementary Notes on the Parameter Ranges for Performance Metrics (DMX Series)
The maximum flow rate can reach 5,678 cubic meters per hour (25,000 gallons per minute), with a wide coverage area that can meet the needs of various scales. Other data indicate a flow rate of 2,950 cubic meters per hour, which may correspond to a different model.
Pumps featuring a multi-stage impeller design can achieve a maximum head of 2,712 meters (8,900 feet), enabling extremely high delivery pressures. Other sources indicate a maximum head of 2,130 meters, which may correspond to different model variants.
The maximum working pressure can reach 275 bar (4,000 psi), and at this pressure rating, the single-shell structural design is well-established and highly reliable.
The maximum operating temperature is up to 204°C (400°F), making it suitable for the conveyance of industrial media within the medium-temperature range.
Maximum speed可达6,000 rpm, specifically designed for high-speed operating conditions and widely applicable.
Available in a range of sizes from 3 to 18 inches, suitable for various piping systems.
🏭 Main Application Industries
Owing to their high pressure, high efficiency, and reliability, Flowserve DMX series pumps are widely used in the following critical industrial sectors:

Oil and gas: this is the core application area for DMX pumps. With a global installed base of over 10,000 units, they firmly underscore their dominant position in the industry.

Specific applications include pipeline transportation of crude oil, refined oil products, and carbon dioxide; water/CO₂ injection in oilfields (for enhanced oil recovery); FPSOs (floating production, storage, and offloading units); and oil–gas separation and processing.

Petrochemicals and Refining:

Specific applications include refining process equipment (such as hydrocracking and hydrotreating), boiler feedwater systems, amine solution transfer, and liquefied natural gas production. A case study from an crude oil pipeline demonstrates that a major U.S. pipeline hub employs a 2,250-horsepower Foster Wheeler DMX BB3 pump for crude oil transportation.

Energy and Electricity:

Specific applications: boiler feedwater systems in conventional thermal power plants and nuclear power stations, as well as nuclear island services.

Water Resources and Seawater Desalination:

Specific applications include seawater reverse osmosis (SWRO), high-pressure water supply (equipped with the specially optimized DMX-RO model), groundwater development and irrigation, and industrial water supply and treatment.

Other industrial sectors:

Specific applications include: mining (dewatering and water supply), pulp and paper manufacturing (boiler feedwater), primary metal industries, and hydraulic boosting, among others.

We hope the information provided above on the Flowserve BB3 pump has been helpful. If you require a selection analysis tailored to a specific project, or would like to compare it with other pump types, please feel free to contact us again at any time.

Casting Capabilities: Equipped with a range of refining facilities, including vacuum induction furnaces, VOD furnaces, AOD furnaces, and LF furnaces, the facility boasts an annual casting capacity of 40,000 metric tons, with individual castings weighing up to 25 metric tons.

Machining Capabilities: We operate more than 300 CNC lathes of various types and a wide range of large and medium-sized CNC machine tools and machining centers, including brands such as OKUMA, OKK, MAZAK, and DAWOO.

Horizontal machining centers, turning centers, vertical machining centers, boring-milling centers, and Mori Seiki horizontal precision machining centers. Annual machining capacity reaches 2 million hours.

Testing Capabilities: Equipped with open-loop and closed-loop test circuits suitable for 380 V, 3,300 V, 6,000 V, and 10,000 V systems, capable of testing motors up to 5,000 kVA.

This open-type test stand is 12 meters deep and has a volume of 3,600 cubic meters, capable of meeting the testing requirements for most centrifugal pumps and systems.

Annual Production Capacity: An average annual output of 8,000 pumps, encompassing centrifugal pumps, canned motors pumps, reciprocating pumps, screw pumps, and high-speed pumps.

System Integration: Conduct system integration design and consolidation based on product specifications, operating conditions, industry standards, and customer branding requirements.

● Auxiliary equipment: lubrication system, sealing system, flushing system, coupling, etc.

● Drive systems: electric motors, steam turbines, diesel engines, hydro turbines, etc.

● Control System: pressure control, temperature control, vibration monitoring, lubrication monitoring, and leak detection, among others.

● Electrical control systems: DCS, MCC, MMS, VFD, and LCP, among others.

Workshop Equipment: Equipped with a complete production line spanning raw-material laboratory testing, component manufacturing, machining, pump-body assembly, nondestructive testing, dynamic balancing, performance testing, painting, and packaging.

● The workshop covers an area of 20,000 square meters and is equipped with a bridge crane capable of lifting 32 tons with a clear headroom of 12 meters.

● The balancing equipment has a precision of G1.0.

● Equipped with a performance test circuit capable of withstanding voltages of 380 V, 3,300 V, 6,000 V, and 10,000 V, a motor with a rated power of up to 5,000 kW, and an A-class-accuracy automated data acquisition and processing system.