Magnetostrictive Sensor for Ram BOP Position Measurement

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for measuring the position, velocity, and movement of rams in ram blowout preventers are inaccurate and prone to errors due to wear, power loss, and high-speed limitations, particularly with potentiometric transducers, and suboptimal placement of magnetostrictive sensors.

Innovation Solution

A magnetostrictive sensor system is integrated into the ram blowout preventer, where a permanent magnet on the piston tail interacts with a waveguide tube, generating a helical return signal used to determine the ram's position, allowing continuous and precise measurement without invasive maintenance, and enabling measurement of velocity and acceleration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If potentiometric transducers are used to measure ram position, then a measurement system is provided, but the measurements become inaccurate due to wear, power loss, and high-speed limitations

Engineering Contradiction:

Improveram position measurement accuracyVSAvoidmeasurement reliability under wear and power loss

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces potentiometric transducers (electrical/mechanical contact-based system) with magnetostrictive sensors that utilize magnetic field interactions. The magnetostrictive sensor system employs a permanent magnet attached to the piston rod and a magnetostrictive waveguide tube, eliminating mechanical contact and wear-prone electrical connections while providing accurate position measurement through magnetic field interactions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetostrictive sensor system is self-powered through the interaction between the permanent magnet and the magnetostrictive material in the waveguide tube. The system uses the motion of the piston rod itself to generate the measurement signal through magnetic field changes, without requiring external power for the sensing mechanism, thus eliminating power loss issues.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If magnetostrictive sensors are placed inside the cylinder cavity, then position measurement is achieved, but maintenance becomes invasive and complex

Engineering Contradiction:

Improvecontinuous position measurementVSAvoidmaintenance complexity

Core Design Contradiction:

Measurement precisionVSEase of repair

Solution Approach 1:

The patent extracts the magnetostrictive sensor components (permanent magnet and waveguide tube) from inside the cylinder cavity and places them on the piston rod exterior. The permanent magnet is attached to the piston rod, and the waveguide tube extends through a sealed opening in the cylinder head, allowing the sensor to measure piston rod position without being located within the contaminated cylinder cavity, thus enabling non-invasive maintenance.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If traditional sensors are used in harsh environments, then measurement is provided, but errors increase due to environmental factors

Engineering Contradiction:

Improveposition measurement accuracyVSAvoidenvironmental impact on measurement

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical contact-based sensing with magnetic field-based magnetostrictive sensing. The magnetic field interactions between the permanent magnet and magnetostrictive waveguide tube are not affected by harsh environmental conditions such as contamination, moisture, or extreme temperatures, providing reliable measurement in environments where traditional mechanical sensors would fail.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This solution provides accurate, continuous measurement of ram position, velocity, and acceleration without the need for re-zeroing, is non-invasive, and can be easily installed in existing systems, enhancing operational safety and efficiency.

Implementation Method 1

a magnetostrictive sensor system is integrated into the ram blowout preventer, where a permanent magnet on the piston tail interacts with a waveguide tube, generating a helical return signal used to determine the ram's position

Methodology Applied

Scientific EffectMagnetostriction: Magnetostriction

Data Source

PatentUS7832706B2RAM BOP position sensor

Publication Date: 2010.11.16 HYDRIL USA DISTRIBUTION LLC

AI summary

A ram-type blowout preventer includes a pair of ram assemblies adapted for controlled lateral movement to and from a vertical bore. Each ram assembly has a hydraulic piston connected at a first end to a ram block and at a second end to a piston tail. A magnetostrictive waveguide tube extends into a bore of at least one piston tail and a permanent magnet is disposed upon the at least one piston tail. The magnetostrictive waveguide tube has a conducting wire to receive an interrogation pulse from a transducer, the interrogation pulse generates a helical return signal in response to a relative position of the permanent magnet with respect to the waveguide tube, and the transducer is configured to receive the helical return signal and output a position of the ram block corresponding to the at least one piston tail.