Laser Piston Position Sensor for Hydraulic Accumulator Volume Detection
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Solution Overview
Problem
Existing methods for determining the hydraulic fluid volume in hydraulic accumulators, such as cable extension transducers and acoustic signal methods, are unreliable and require additional sensors, leading to decreased accuracy and increased maintenance costs in oilfield applications.
Innovation Solution
A laser piston position sensor is attached to the hydraulic accumulator, emitting a laser through an aperture to the piston, allowing for non-invasive measurement of piston position and fluid volume calculation based on the time of reflected light, without the need for physical contact or additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cable extension transducers are used to determine piston position, then piston position can be measured, but physical invasion into the accumulator and multiple mechanical parts decrease reliability and increase maintenance costs
Solution Approach 1:
The patent replaces the mechanical cable extension transducer system with an optical measurement system. A laser transmitter emits light that reflects off the piston, and a laser receiver detects the reflected light to determine piston position. This substitution eliminates physical cable connections and mechanical moving parts inside the accumulator, thereby improving reliability while maintaining measurement precision.
2Reliability
If acoustic signals are transmitted into the accumulator to determine piston position, then physical intrusion is avoided, but additional temperature and pressure gauges are required which decrease reliability and accuracy
Solution Approach 1:
The patent replaces the acoustic signal method with an optical measurement system using laser transmission. The laser light travels through the hydraulic fluid to reflect off the piston, eliminating the need for temperature and pressure compensation that would be required for acoustic wave-based measurements. This maintains measurement accuracy without requiring additional sensors, thereby preserving system reliability.
3Adaptability or versatility
If additional sensors are installed within the accumulator to measure temperature and pressure, then piston position can be determined using acoustic waves, but the introduction of additional sensors decreases reliability and accuracy
Solution Approach 1:
The patent substitutes the acoustic measurement method requiring temperature and pressure sensors with an optical laser measurement system. The laser wavelength and speed of light in the medium are not significantly affected by temperature and pressure variations in the operational range, eliminating the need for additional sensors. This maintains measurement versatility while improving system reliability by reducing the number of components.
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 laser piston position sensor enhances reliability by being non-invasive and eliminating the need for mechanical parts, providing accurate and efficient determination of hydraulic fluid volume, thus ensuring sufficient fluid for safety components in subsea drilling systems.
Implementation Method 1
receiving reflected light from the piston
Implementation Method 2
a laser sensor attached to the sensor housing in the cavity, that emits a laser directed through the lens and aperture in the accumulator housing to the piston
Implementation Method 3
a lens positioned in the recess of the sensor housing, and exposed to the cavity in the sensor housing, the lens positioned between the cavity in the sensor housing and the aperture of the accumulator housing
Data Source
AI summary
A laser piston position sensor for determining the position of a piston within an accumulator, the laser piston position sensor configured to attach to an end of the accumulator, and the accumulator having an aperture in the end thereof exposing the piston within the accumulator to the laser piston position sensor. The laser piston position sensor including a sensor housing enclosing a cavity containing a low pressure gas, and defining an opening from the cavity toward the accumulator, a laser sensor positioned within the cavity for emitting a laser toward the piston of the accumulator via the opening in the sensor housing and the aperture in the accumulator, and a transparent lens positioned between the laser sensor and the accumulator to allow passage of the laser from the laser sensor to the piston, and to separate gases in the accumulator from gases in the cavity of the sensor housing.