Expanding Plug Valve Seal Leak Detection by Cavity Pressure
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Solution Overview
Problem
Current valve systems in the oil and gas industry face challenges in effectively detecting leaks in double block and bleed expanding plug valves, which are crucial for maintaining seal integrity and ensuring safe fluid flow.
Innovation Solution
A double block and bleed expanding plug valve equipped with a pressure sensor that monitors pressure changes during the valve's operation, allowing for the detection of seal leaks by comparing initial and fully-seated pressures, and utilizing a processor to analyze pressure and temperature data to determine seal integrity and leak severity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional double block and bleed systems are used with multiple valves, then seal integrity can be maintained through redundant sealing, but device complexity increases and ease of operation deteriorates
Solution Approach 1:
The patent combines multiple sealing functions into a single expanding plug valve body. The valve body integrates two sealing surfaces (upstream and downstream seals) that can independently seal against the inner bore, eliminating the need for separate valves while maintaining redundant sealing capability. This merging approach preserves reliability through multiple seals within one device while reducing overall system complexity.
Solution Approach 2:
The expanding plug valve performs multiple functions within a single device: it provides primary flow control, upstream sealing, downstream sealing, and integrated leak detection. The valve body universally handles both sealing functions that traditionally required separate valves, along with built-in pressure sensing capability for monitoring seal integrity, thereby improving ease of operation.
2Measurement precision
If pressure monitoring is implemented to detect seal leaks, then measurement precision of seal integrity improves, but device complexity increases
Solution Approach 1:
The pressure sensor is integrated directly into the valve body's internal cavity, merging the monitoring function with the valve structure. This allows pressure monitoring to detect seal leaks by measuring pressure changes in the sealed cavity, achieving precise seal integrity detection without requiring external monitoring equipment or complex external sensor installations.
Solution Approach 2:
The valve body's internal cavity serves dual purposes: it contains the expanding plug mechanism and simultaneously acts as the monitoring chamber for the pressure sensor. The sealed cavity automatically isolates the sensor from external interference, allowing the valve structure itself to provide the monitoring environment without additional complex instrumentation.
3Reliability
If continuous pressure monitoring is performed during valve operation, then reliability of leak detection improves, but use of energy increases
Solution Approach 1:
The system performs pressure monitoring at critical transition points during valve operation (during expansion and sealing phases) rather than continuous monitoring. This periodic sampling at key moments provides reliable leak detection data while minimizing energy consumption compared to continuous monitoring throughout the entire operational cycle.
Solution Approach 2:
The valve's operational movements (expansion and sealing actions) naturally create pressure changes that the sensor detects. The system uses the valve's own operational dynamics to generate the monitoring signals, eliminating the need for external energy-intensive pumping or pressurization systems to facilitate leak detection.
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 provides real-time monitoring and analysis of seal integrity, enabling prompt detection of leaks and maintenance, thereby ensuring reliable fluid flow and extending seal life.
Implementation Method 1
a pressure sensor adapted to sense pressure within an internal cavity of the plug valve
Implementation Method 2
The valve is actuated by fluid pressure to move an expanding plug from an open to a closed position
Data Source
AI summary
Improved valve seal and integrity systems and methods are disclosed. Pressure in an internal cavity of a valve may be monitored and stored to assist in determining whether one or more seals in the valve are leaking. Internal cavity temperature may also be recorded and monitored to assist in determining whether there are any valve seal leaks. Expected pressure corresponding to a detected internal cavity pressure (that may be determined by correlating temperature and known fluid properties) may be compared to detected internal cavity pressure to assist in determining the existence of valve leaks. Internal cavity pressures and pressure differentials over time may be used to determine remaining valve seal life, leak severity, and/or integrity of a check valve on the valve. Indications of seal life, leak severity, seal integrity, and/or check valve integrity may be displayed to an end user or otherwise provided to a database or computer.