Pipeline Pig Detector Pressure Isolation Mechanism
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Solution Overview
Problem
Existing pipeline pig detection systems fail to accurately signal the passage of a pipeline pig due to pressure variations, as springs used to hold triggering mechanisms may not be strong enough against higher pressures or may remain inactive during lower pressures.
Innovation Solution
A pig detector mounted outside the pipeline with a trigger ball and actuator mechanism, isolated from internal pressure via o-rings and a bypass port, which activates catch fingers and an indicator to visually signify the pig's passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a spring is used to hold the triggering mechanism against pipeline pressure, then the mechanism can maintain position under normal pressure, but the detection reliability deteriorates when pressure falls below or exceeds the anticipated range
Solution Approach 1:
The triggering mechanism is segmented into two separate systems: a trigger ball that contacts the pig directly to initiate activation, and a separate spring-loaded plunger that actually triggers the indicator mechanism. This segmentation isolates the indicator from direct pipeline pressure exposure while maintaining the positioning function, resolving the contradiction between stability and reliability across varying pressure ranges
Solution Approach 2:
The trigger ball acts as an intermediary between the pig and the plunger mechanism. Instead of the plunger directly contacting the pig (which would expose it to full pipeline pressure), the trigger ball transfers the mechanical action from the pig to the plunger, allowing reliable detection without direct pressure exposure on the triggering components
2Force
If the spring force is increased to handle higher pipeline pressures, then the mechanism can maintain position under high pressure, but the mechanism fails to activate when pipeline pressure is lower than anticipated
Solution Approach 1:
The system uses a dynamic trigger mechanism where the trigger ball moves freely to contact the pig and initiate activation. The spring force on the plunger is optimized for normal operating conditions, while the trigger ball's direct contact with the pig provides the additional force needed to overcome the spring resistance during pig passage, ensuring reliable activation across varying pressure conditions
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 system reliably indicates the passage of a pipeline pig by separating the actuator from internal pressure fluctuations, ensuring accurate detection regardless of pipeline pressure variations.
Implementation Method 1
The actuator is resiliently urged downwardly by an actuator spring so as to cause the trigger to protrude into the space in the pipeline
Implementation Method 2
An indicator spring is mounted within the housing to resiliently urge the indicator upwardly beyond the indicator housing so as to be visible
Implementation Method 3
The catch fingers are provided with a garter spring to urge them radially inwardly towards the central axis
Data Source
AI summary
A device for indicating the passage of a pig beyond a predetermined location in a pipeline comprising a pig detector connected to a pipeline and communicating with the interior of the pipeline through an opening at the location. A means for divorcing the pressure inside the pipeline from the pressure outside the pig. A trigger mounted in the pig detector and adapted to project into the interior of the pipeline through the opening, an indicator associated with the pig detector, a cylindrical indicator being slidably mounted within the indicator housing, catch fingers mounted in the housing for movement toward and away from the central axis of the housing, a catch spring for urging the fingers towards the central axis, an indicator spring mounted within the housing for urging the indicator beyond the indicator housing so as to be visible and to provide an indication that a pig has passed.