Durham Pipeline Technology - Pipeline Crawlers

DPT Pipeline tractors, also known as pipeline crawlers, are based on patented bristle tractor technology. Unlike other tractors or crawlers which use wheels or tracks, DPT’s self-propelled machines use oversized brushes to generate significant traction forces.

TETHERED PIPELINE TRACTORS

DPT pipeline tractors can be supplied with pneumatic, hydraulic or electrical actuators. The tools are powered and controlled using dedicated umbilicals with lengths from tens of metres to several kilometres.

PRINCIPLE OF TRACTOR OPERATION

DPT tractors operate in a "natural" way, they use the conditions in which they operate instead of fighting against them. The tractors, or crawlers, use a series of oversized pre-inclined brushes which are easier to push forward than to pull back. Where two sets of such brushes are interconnected by a mechanism that generates a reciprocating motion towards and away from each other, the whole assembly moves in successive steps.

FREE-SWIMMING PIPELINE PIGS (SHUTTLEPIG CRAWLERS)

ShuttlePig crawlers are free-swimming tools that extract power from the pipeline flow and are able to travel with or against the flow in oil, gas and multi-phase pipelines. In its most advanced configuration, the ShuttlePig free-flow tractors use electrical motors powered by battery packs which are rechargeable using an onboard mini-power plant that includes a turbine, generator and control module.

DPT PIPELINE CRAWLERS - POWERFUL, VERSATILE, CONTROLLABLE

Unlike conventional pigs, the movement of DPT pipeline crawlers is controllable, does not depend on differential pressure, allows the free flow of fluid in either direction and offers a negligible pressure drop across the machine.

By customising the bristle material, dimensions and arrangement, DPT tractors can accommodate significant variations in diameter, travel through damaged or partially collapsed pipes and overcome significant debris and obstacles.

All DPT pipeline crawlers are reversible and bi-directional and can operate in pipes and tubular conduits of irregular cross-sectional size or shape, including elbows and bends down to 1.5D bend radius, mitred bends, vertically ascending or descending pipes.

COST EFFECTIVE BRISTLE-TRACTOR TECHNOLOGY

Pipelines can be unpiggable due to a variety of reasons: changes in diameter, presence of unsuitable valves, tight or mitred bends, low operating pressure, low flow or absence of flow, lack of launching and receiving facilities, dented or collapsed areas, excessive debris or scale build-up, short and dead-end sections, and the list can go on.

The introduction of DPT bristle-tractor technology offers significant CAPEX and OPEX reductions over conventional pigging, especially in cases where the lines are not piggable.

DPT CRAWLER APPLICATIONS

DPT crawlers offer cost-effective alternatives to conventional pigging and inspection methods as well as new ways to assist in a flow maintenance programme:

• CCTV inspection of pipelines, risers and pipework
• Regular and advanced cleaning
• De-waxing
• Metal loss detection
• Crack detection
• Deployment of calliper pigs
• Deployment of isolating plugs
• Buckling detection in new-built pipelines
• Recovering stuck pigs