Dual-Diameter Pigs - Steel Mandral Pigs - Pipeline Pigs - Pipeline Pigging & Equipment

Pipeline Pigging · Steel Mandrel Pigs

Dual Diameter
& Multi-Diameter Pigs

Custom engineered steel mandrel pigs with slotted discs that keep sealing through a change in pipe size, so one run covers the whole line.

Steel Mandrel Pigs

Applications & Features

Applications

Pipelines that transition between two different nominal pipe diameters within the same pigging run, such as 6" to 8" or 8" to 10"
Multi diameter pipeline systems with three or more bore changes in a single run
Gathering systems and flow lines where pipe size changes are common due to tie-ins and expansions
Batching, product separation, and displacement across varying diameter sections
Cleaning operations in multi diameter systems when equipped with brush or blade attachments
Applications where standard fixed diameter pigs cannot be used without a launcher or receiver change out at the diameter transition

Features

Uniquely designed steel mandrel body engineered to negotiate piping configurations with two or more different nominal pipe diameters in a single pass
Slotted dual diameter polyurethane discs flex to maintain sealing contact across both bore sizes as the pig transitions from one diameter to the next
Available starting at 3" x 4" and larger diameter combinations
Can be equipped with brushes for cleaning operations in multi diameter systems
All wearing components, discs and cups, are field replaceable
Each dual or multi diameter pig is engineered to the specific pipe dimensions of the customer's system, so standard off the shelf configurations do not apply

Custom Engineering Required

Dual and multi diameter pigging is a specialized application. The pig design, including disc geometry, mandrel length, and sealing configuration, must be matched specifically to the exact bore sizes, transition length, and flow conditions of the pipeline system. There is no one size fits all solution for multi diameter pigging. Pigs Unlimited engineers these pigs to order based on detailed pipe specifications provided by the customer. If you are planning a dual or multi diameter pigging program, contact us to discuss your system's configuration before ordering.

Available Model

DDP — Dual Diameter Pig	Carbon steel mandrel body fitted with slotted dual diameter polyurethane discs engineered to seal in both bore sizes. Available starting at 3" x 4" and larger. Brush and blade options available for cleaning applications. Each pig is custom engineered to the customer's specified pipe dimensions.

Available Options

Brushes for on stream or pre-commissioning cleaning in multi diameter systems
Polyurethane blades for paraffin and soft deposit removal
Disc elastomer options: neoprene, viton, EPDM, Buna-N, and other compounds for chemical compatibility
Varying disc durometers for different bore tolerance requirements
Transmitter or pinger cavity for pig tracking
Gauging plate for bore verification
Carbon steel, stainless steel, or aluminum mandrel body
Custom multi diameter configurations with three or more diameter transitions available on request

Dual and multi diameter pigging requires custom engineering. Contact us to discuss your pipeline configuration.

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