Magnetic Descent Control Device Eddy Current Braking
Solution Overview
Problem
Conventional descent control systems for emergency escape from rig platforms face challenges such as variability in braking performance, potential overheating and wear of components, and risk of human error due to manual engagement, which can lead to non-compliance with safety standards and increased risk of accidents.
Innovation Solution
A descent control device utilizing a drive assembly with a planar ferromagnetic moving element and magnets to induce a magnetic field that opposes acceleration, providing a passive braking mechanism without the need for manual engagement, thereby ensuring controlled descent and reducing the risk of overheating and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction-based braking systems are used to control descent, then braking force can be achieved, but variability in braking performance and overheating/wear of components occurs
Solution Approach 1:
The patent replaces the mechanical friction-based braking system with an electromagnetic braking system. The electromagnetic brake uses magnetic fields generated by magnets and conducting plates to create eddy currents that oppose the motion of the drive assembly, eliminating the need for physical contact between brake pads and drums. This substitution resolves the contradiction by providing consistent braking performance through electromagnetic forces while avoiding the overheating and wear problems inherent in friction-based systems.
Solution Approach 2:
The patent changes the fundamental parameter of braking mechanism from mechanical friction to electromagnetic induction. By using magnets mounted on the rotor and conducting plates positioned nearby, the system generates a magnetic field that induces eddy currents in the conducting plates. These eddy currents create a magnetic field that opposes the motion of the rotor, providing controlled descent. This parameter change eliminates the harmful thermal and mechanical wear effects while maintaining reliable braking performance.
2Reliability
If manual engagement of braking systems is required, then braking control can be achieved, but human error risk increases
Solution Approach 1:
The electromagnetic braking system is designed to engage automatically when the enclosure begins its descent along the cable. The motion of the drive assembly rotating the rotor with magnets automatically induces eddy currents in the conducting plates, creating the braking force without requiring any manual intervention. This self-activating mechanism eliminates human error risk while maintaining precise braking control, as the system responds automatically to the descent motion itself.
Solution Approach 2:
The patent replaces manual mechanical engagement mechanisms with an automatic electromagnetic engagement system. The electromagnetic brake activates automatically through the motion-induced electromagnetic field, eliminating the need for operators to manually engage brakes. This substitution removes the element of human error from the braking control process while maintaining reliable and accurate descent rate control.
3Reliability
If friction-based braking systems are used, then descent control can be achieved, but maintenance and inspection requirements increase
Solution Approach 1:
The patent replaces the friction-based braking system with an electromagnetic braking system that has no contacting parts. The electromagnetic brake uses magnets and conducting plates that interact through magnetic fields without physical contact, eliminating wear and tear on components. This substitution dramatically reduces maintenance requirements, as there are no brake pads to replace, no drums to inspect for wear, and no friction surfaces to monitor for corrosion or degradation.
Solution Approach 2:
The patent changes the braking mechanism from mechanical friction to electromagnetic induction, fundamentally altering the maintenance profile. The electromagnetic system with magnets and conducting plates has no consumable parts that wear down through friction. The conducting plates may require inspection for damage but do not experience the progressive wear, overheating, and corrosion issues that plague friction-based systems, thereby reducing both maintenance frequency and complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves consistent and controlled descent rates, reducing the risk of accidents and ensuring compliance with safety standards by generating a braking force through induced eddy currents, which is proportional to the descent speed, resulting in a smooth and controlled landing.
Implementation Method 1
a magnetic field may be induced by rotational movement of the moving element relative to the at least one conducting plate
Implementation Method 2
a magnetic field may be induced by rotational movement of the moving element relative to the at least one conducting plate in a direction to oppose acceleration
Data Source
AI summary
A magnetic descent control device is disclosed. The device comprises an input shaft affixed to a rotating driven sheave acting as a drive assembly, which grips a cable guiding the descent path of a body carrying cage. The input shaft has a shoulder upon which rests a rotor. The rotor is encased within a front and back enclosure of conductive material. Disposed along at least one surface of the rotor and/or at least one of the conductors, is a series of magnets such that rotation of the rotor relative to the conductors creates relative motion between the magnets' magnetic field and the conductor inducing eddy currents in the conductor that oppose the magnetic field creating a rotational braking force. As a result, very precise and/or controllable descent may be obtained over a broad range of descent angles and/or distances with little or no mechanical wear or risk of overheating. Preferably, the sheave gripping the cable may have a circumferential groove to better improve traction and grip of the cable. A plurality of such devices may be applied to drive assemblies contacting a common cable, and a plurality of cables may support the cage, each affixed with at least one descent control device.