DUAL DIAMETER Cleaning Pigs
Designed for reducers, diameter transitions, and variable pipeline sections.
When pipelines transition between two diameters, standard cleaning pigs can lose sealing force or cleaning efficiency. Enduro’s Dual-Diameter Cleaning Pigs are engineered to navigate those transitions while maintaining consistent contact and debris-removal performance.
Built in Tulsa and designed for real-world field conditions, our dual diameter pigs help operators clean efficiently across reducers, diameter changes, and varying pipeline sections.
Which Cleaning Pig Works in Pipelines with Diameter Changes?
Pipelines that contain changes in diameter typically require dual-diameter or multi-diameter cleaning pigs. These pigs use specially designed sealing cups and discs that maintain contact across multiple pipe sizes while safely navigating reducers, expanders, and varying internal diameters. The best pig depends on the amount of diameter change, pipeline geometry, and cleaning objectives.
What Is a Dual Diameter Cleaning Pig?
A dual diameter cleaning pig, sometimes referred to as a reducer pig or transition pig, is designed to travel through pipelines with two different nominal diameters — such as 16” to 14” or 24” to 20” transitions — while maintaining effective sealing and cleaning action.
These pigs are commonly used in lines with reducers, expansion points, or variable-diameter segments where a standard pig would be ineffective or risk bypassing.
Want to understand the engineering challenges behind diameter transitions?
Read our article:
What Problem Does a Dual-Diameter Cleaning Pig Solve?
(Custom options available for unique applications.)
Dual Diameter vs. Multiple-Diameter Pigging Systems
Dual diameter and multiple-diameter pigging systems are designed for pipelines where the internal diameter changes during the run, but the terms describe different pipeline conditions.
A dual diameter pig is designed to travel through two primary pipeline diameters. For example, a pipeline may transition between a larger mainline section and a smaller-diameter section connected through a reducer or transition.
A multiple-diameter pigging system may involve more than two internal diameters or a more complex combination of pipeline sizes, wall thickness changes, reducers, and varying internal geometry.
In either case, the challenge is maintaining effective sealing and stable pig travel as the available internal diameter changes. A pig must be able to compress through smaller sections while maintaining enough contact in larger sections to support the objective of the run.
Depending on the application, dual- and multiple-diameter pig designs may be used for:
- Pipeline cleaning
- Product batching and separation
- Liquid displacement
- Dewatering
- Pipeline commissioning
- Pre-ILI cleaning and preparation
- Specialty maintenance operations
The correct design depends on the complete pipeline profile—not simply the largest and smallest nominal pipe sizes.
For complex multi-diameter systems, Enduro evaluates the sequence of diameter changes, reducer geometry, bend radius, pipeline fittings, operating conditions, and the objective of the run before recommending a pig configuration.
When Should You Use a Dual Diameter Pig?
Dual diameter pigs are ideal when:
- Your line includes diameter transitions
- You need consistent cleaning across reducers
- You are preparing for inline inspection (ILI)
- Debris removal is required in variable diameter segments
- Maintaining flow efficiency across transitions is critical
Cleaning Performance Across Diameter Changes
Enduro’s dual diameter pigs are engineered to:
- Maintain sealing force through diameter transitions
- Remove wax, scale, and operational debris
- Capture ferrous debris when configured with magnets
- Support ILI preparation by improving line cleanliness
- Reduce risk of stalled runs at reducers
Configurable to Your Pipeline Conditions
Dual diameter pigs can be configured based on:
- Pipeline diameters and reducer type
- Product type (crude, refined products, gas, NGL, water)
- Debris profile (wax, scale, metal fines, sludge)
- Flow conditions
- Maintenance vs. inspection preparation objectives
Available configuration options include:
- Cups or discs
- Brush elements
- Magnetic elements
- Gauge plates
- Bypass systems
- Specialty urethane formulations
Common Dual Diameter Transition Examples
- 16” x 14”
- 20” x 16”
- 24” x 20”
- 30” x 24”
Built for ILI Preparation
Proper cleaning is critical before an inline inspection run. Dual-diameter pigs are frequently used in preparation programs to ensure that inspection tools maintain consistent contact across diameter changes.
A clean line improves the quality of inspection data and reduces the risk of missed or masked anomalies.
Want to learn more about the pipeline pigging process? Pipeline Pigging Explained: Process, Types & Applications
How Dual Diameter Cleaning Pigs Navigate Pipeline Transitions
Dual diameter cleaning pigs are designed to maintain sealing force and cleaning performance as they travel through varying pipeline diameters. Flexible cups compress and expand as the tool moves through reducers and transition sections, helping maintain wall contact for debris removal, batching, and preparation for inline inspection.
Example of a dual diameter cleaning pig maintaining sealing contact while traveling through pipeline reducers and changing internal diameters
Many dual diameter applications require custom pig designs. See examples of specialty-cleaning pigs designed for unique pipeline conditions.
What Problem Does a Dual Diameter Cleaning Pig Solve?
Most pipeline cleaning pigs are designed for a single internal pipeline diameter. That works well when the pipeline remains consistent from launcher to receiver.
The challenge begins when a pipeline changes size.
Diameter transitions are common in:
- pipeline expansions
- tie-ins
- terminal connections
- aging infrastructure upgrades
- gathering systems
- offshore and transmission systems
A standard cleaning pig may struggle to maintain proper sealing force as the pipeline diameter changes. This can reduce cleaning effectiveness, allow debris bypass, increase wear, or create inconsistent pig performance throughout the run.
Enduro Dual Diameter Cleaning Pigs are specifically engineered to maintain effective sealing, cleaning, and tracking performance across multiple pipeline diameters.
Because every pipeline system is different, Enduro designs dual diameter pigs around your:
- pipeline sizes
- bend radius
- debris conditions
- flow rates
- pressure requirements
- cleaning objectives
The result is a pig designed for your actual pipeline conditions — not a generic “off-the-shelf” solution.
Why Standard Pigs Struggle in Diameter Changes
A conventional cleaning pig is typically built around one consistent pipe size.
When that pig encounters a larger or smaller diameter section, several problems can occur:
Loss of Seal
If the pig cannot maintain proper contact with the pipe wall, product and debris may bypass the pig instead of being pushed ahead.
Reduced Cleaning Efficiency
Inconsistent wall contact can leave behind:
- liquids
- sludge
- paraffin
- scale
- construction debris
Excessive Wear
Improper compression through transitions can increase wear on cups, discs, and sealing components.
Stalling or Damage Risk
Some pipeline transitions create conditions where improperly designed pigs can become unstable or damaged.
Enduro Dual Diameter Cleaning Pigs are engineered to flex and seal through pipeline transitions while maintaining cleaning performance throughout the run.
Why Dual Diameter Cleaning Pig Design Can Be Challenging
Not all diameter transitions are the same. While a dual diameter cleaning pig may appear similar to a standard cleaning pig, the design process often requires careful consideration of the pipeline's configuration and operating conditions.
Factors that can influence dual diameter cleaning pig design include:
- The ratio between the larger and smaller pipe diameters
- Bend radius requirements
- Debris type and expected debris volume
- Flow rates and operating pressure
- Launcher and receiver dimensions
- Cleaning objectives
- Inline inspection preparation requirements
A cleaning pig must maintain effective sealing contact in both pipe sizes while remaining flexible enough to navigate the transition area without damage or loss of cleaning effectiveness.
For this reason, dual diameter cleaning pigs are often engineered specifically for the application rather than selected from a standard catalog configuration.
Why the Complete Pipeline Profile Matters
The largest and smallest pipeline diameters are only part of the information needed to evaluate a dual- or multiple-diameter pigging application.
The sequence and location of diameter changes can affect pig design and performance. A pipeline that moves from a larger diameter into a smaller section and then returns to the larger diameter may require different design considerations than a pipeline with several transitions, varying wall thicknesses, or multiple reducer configurations.
Important information may include:
- Nominal pipeline sizes
- Actual internal diameters
- Wall thickness changes
- Order and length of each diameter section
- Reducer type and transition geometry
- Minimum bend radius
- Valve and fitting restrictions
- Launcher and receiver dimensions
- Product and operating conditions
- Previous pigging history
- Cleaning, batching, displacement, or inspection objectives
This information helps determine the appropriate pig body design, sealing configuration, flexibility, and optional cleaning components.
A successful multi-diameter pigging system must be designed for the entire route from launcher to receiver—not just one transition point.
Common Dual Diameter Cleaning Pig Applications
Dual diameter cleaning pigs are frequently used in pipeline systems where changes in diameter occur as part of the original design or after system modifications.
Common applications include:
- Pipeline diameter transitions
- Gathering systems
- Facility tie-ins
- Pipeline expansions and upgrades
- Inline inspection preparation programs
- Cleaning programs involving reducers or changes in nominal pipe size
These applications often require a cleaning pig that can maintain sealing performance across multiple pipe diameters while continuing to remove debris effectively.
STS Cleaning Pig Specifications
Dual Diameter Cleaning Pig Specifications
Body Construction
Cleaning Elements
Optional Components
Pipeline Diameter
Primary Applications
ILI Preparation
Pipeline Types
Tracking Compatibility
Manufacturing
Steel-bodied cleaning pig designed to travel through pipelines with diameter transitions while maintaining sealing and cleaning performance.
Flexible cup and disc configurations designed to maintain sealing and cleaning effectiveness across reducers and diameter changes.
Magnets, brushes, and gauging plates can be added depending on debris type and cleaning requirements.
Designed for pipelines transitioning between two nominal diameters.
Pipeline cleaning across diameter transitions, reducers, and fittings.
Commonly used prior to inline inspection runs to improve pipeline cleanliness across diameter transitions.
Natural gas, crude oil, and refined product pipelines.
Transmitters can be installed to allow pig tracking with geophones, receivers, or NIPS units.
Designed and built in Tulsa, Oklahoma by Enduro Pipeline Services.
Planning a Dual- or Multiple-Diameter Pigging Project?
Share the pipeline diameters, transition sequence, reducer geometry, bend requirements, and operational objective with Enduro’s cleaning pig team. We can help evaluate the complete route and recommend an appropriate configuration.
Phone: 800-752-1628
Discuss Your Pipeline Configuration
Or request a recommendation.
For sizing, configuration recommendations, or custom builds, call 800-752-1628 to speak with our Director of Pipeline Cleaning and Maintenance, JR Morgan, jrm@enduropls.com, or submit a quick quote request online.
Why Operators Contact Enduro for Dual Diameter Cleaning Pigs
- 30+ years of cleaning pig expertise
- Tulsa-built manufacturing
- Custom configurations
- Fast turnaround
- Direct technical support from cleaning pig specialists
Dual diameter cleaning pigs are among the most specialized cleaning pig configurations used in pipeline maintenance and inline inspection preparation.
Our team works with operators regularly to evaluate pipeline geometry, transition requirements, debris conditions, and inspection objectives before recommending a design. Many applications require custom configurations to achieve reliable sealing performance and cleaning effectiveness across diameter changes.
Whether the application involves routine maintenance, batching, or preparation for inline inspection, Enduro can help determine the most effective cleaning pig configuration for the project.
FAQs
What is a dual diameter cleaning pig?
A dual diameter cleaning pig is designed to move through pipelines that transition between two nominal diameters while maintaining sealing and cleaning effectiveness.
Can dual diameter pigs include magnets or brushes?
Yes. Magnetic and brush elements can be added depending on the debris type and cleaning objective.
Are dual diameter pigs used before ILI?
Yes. They are commonly used during cleaning programs prior to inline inspection to improve line cleanliness across diameter transitions.
How do I determine the correct dual diameter configuration?
Configuration depends on the two diameters, reducer geometry, debris profile, product type, and whether the run is for maintenance cleaning or ILI preparation.
What is the difference between a dual diameter pig and a multiple-diameter pig?
A dual-diameter pig is designed to travel through two primary pipeline diameters, while a multiple-diameter pigging system may involve more than two internal diameters or a more complex sequence of diameter changes. Both require specialized designs that can maintain sealing and stable travel as pipeline geometry changes
Related Cleaning Pigs
Not sure which cleaning pig is best for your pipeline? Compare pipeline cleaning pig types to see how STS, Advantage, Bi-Directional, and urethane pigs differ.
Come See How They’re Made
At Enduro Pipeline Services, we manufacture pipeline cleaning pigs in Tulsa, Oklahoma and regularly host customer tours and pigging education sessions.
Whether you are new to pigging or managing a complex cleaning program, our team can help you better understand:
- pig selection
- pipeline cleaning strategies
- dual diameter applications
- tracking solutions
- inspection preparation
We believe the best solutions start with education.
Schedule a tour, class, or consultation and come see how Enduro cleaning pigs are designed and manufactured.
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