Segmented Push-Cable Core for Tight Pipe Turns
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Solution Overview
Problem
Conventional push-cables used for pipe inspections are limited in flexibility and durability, particularly when navigating tight turns and small diameters, as they rely on a semi-rigid core that can fail under stress and are not suitable for miniaturized inspection cameras in varied environments.
Innovation Solution
A push-cable design featuring a central core wrapped with small-diameter fiberglass rods and a non-metallic sheathing, allowing for increased flexibility and reduced bend radius, along with a camera head that integrates a Sonde coil for location tracking and improved heat dissipation, and a pipe guide to stabilize the camera during inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a semi-rigid core is used in the push-cable, then the cable has sufficient stiffness to be pushed down the pipe, but the cable cannot make tight turns and has limited flexibility
Solution Approach 1:
The central core is segmented into multiple small-diameter rods (three rods of 0.030 inch diameter) rather than a single large rod. This segmentation allows each rod to bend more easily while collectively providing sufficient stiffness through their combined structural support, enabling the cable to navigate tight turns in small-diameter pipes.
Solution Approach 2:
The push-cable uses a composite construction combining multiple materials: small-diameter rods (likely fiberglass or similar composite material), flexible polymer jacketing, and helical wire reinforcement. This composite structure provides both the necessary stiffness from the rods and flexibility from the polymer and helical elements, resolving the contradiction between rigidity and bendability.
2Volume of moving object
If the pipe diameter decreases, then the inspection system can access smaller pipes, but the conventional push-rod reaches the limits of its performance
Solution Approach 1:
By dividing the central core into multiple small-diameter rods instead of a single large rod, the cable maintains sufficient structural integrity and stiffness while achieving a smaller overall diameter. This segmented structure allows the cable to flex and bend more easily, enabling it to navigate tight turns in small-diameter pipes without failing.
Solution Approach 2:
The invention changes key parameters of the push-cable: reducing rod diameter from conventional sizes to 0.030 inch, increasing the number of rods to three, and adjusting the helical wrap configuration. These parameter changes collectively reduce the cable's bend radius and overall diameter while maintaining pushability, enabling reliable operation in pipes as small as 2 inches in diameter.
3Adaptability or versatility
If the push-cable is made more flexible to navigate tight turns, then the cable can make sharper turns, but the cable loses the stiffness needed to be pushed hundreds of feet
Solution Approach 1:
The central core is divided into three separate small-diameter rods instead of a single large rod. This segmentation allows individual rods to bend more easily for tight turns while their collective arrangement maintains sufficient stiffness for pushing the cable long distances through the pipe.
Solution Approach 2:
The push-cable employs a dynamic structure where the central core provides stiffness for pushing, while the helical wire wrap and flexible polymer jacketing provide flexibility for turning. This dynamic combination of rigid and flexible elements allows the cable to adapt its properties based on operational needs - stiff when being pushed, flexible when navigating turns.
Data Source
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AI summary
In accordance with the present invention a push-cable comprises a central core including a least one conductor, a plurality of non-metallic resilient flexible stiffness members surrounding the core, and a layer of sheathing surrounding the stiffness members.