Retrievable Pressure Sensor Diaphragm Sealing
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Solution Overview
Problem
Existing retrievable pressure sensors face challenges in overpressure environments, such as subsea oil applications, where they are difficult to replace without rendering them inoperable and often result in process fluid discharge, due to valve mechanisms that can become fouled and non-functional over time.
Innovation Solution
A pressure-transferring arrangement with separation diaphragms and a pressure pad that allows for hermetic sealing and pressure transfer, enabling safe and reliable replacement of pressure sensors without opening the pipe wall, using a system of diaphragms and a third volume for controlled pressure adjustment to facilitate sensor retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If valve mechanisms are used to block flow for sensor replacement, then sensor replacement is enabled, but the valve becomes fouled by process fluid and may become non-operable over time
Solution Approach 1:
The invention extracts the flow blocking function from a valve mechanism and implements it directly through the sensor assembly itself. The sensor can be removed while the process fluid flow is blocked by the pipe geometry and the remaining sealing arrangement, eliminating the need for a separate valve that would be subject to fouling.
Solution Approach 2:
The invention introduces a sealing arrangement that acts as an intermediary between the sensor and the process fluid. This sealing mechanism enables controlled isolation of the sensor from the fluid stream during replacement, allowing the sensor to be removed without requiring a valve and without discharging process fluid.
2Ease of repair
If valve mechanisms are used for sensor replacement, then sensor replacement is possible, but process fluid is discharged into the environment
Solution Approach 1:
The invention removes the valve mechanism entirely and replaces it with a sealing arrangement integrated into the sensor assembly. This eliminates the source of process fluid discharge that would occur when valves are opened for sensor replacement.
Solution Approach 2:
The sealing arrangement serves as an intermediary that prevents process fluid from escaping during sensor replacement. It maintains isolation between the process fluid and the external environment throughout the replacement procedure.
3Ease of repair
If the sensor is left in an open position for extended periods, then the sensor can be replaced, but the sensor becomes subject to fouling by process fluid
Solution Approach 1:
The invention implements preliminary sealing action by providing a sealing arrangement that is automatically engaged when the sensor is removed. This preliminary sealing prevents process fluid from accessing and fouling the sensor before replacement is complete.
4Reliability
If hermetic sealing is implemented with multiple diaphragms, then safety and reliability are improved, but device complexity increases
Solution Approach 1:
The invention segments the sealing function into multiple independent diaphragms, each providing a separate barrier against process fluid. This segmentation creates redundant sealing paths that improve safety and reliability while maintaining a manageable structural complexity.
Solution Approach 2:
The invention implements a nested sealing structure where multiple diaphragms are arranged concentrically, with each diaphragm nested within the sealing system of the previous one. This nested arrangement provides multiple barriers against process fluid while organizing the complexity in a compact, systematic manner.
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
Enables safe and reliable replacement of pressure sensors in overpressure environments, preventing operational disruptions and environmental contamination, while meeting strict safety and reliability requirements.
Implementation Method 1
a first separation diaphragm (5) for separating between the process fluid and the pressure-transferring fluid in the first cavity (7), and a second separation diaphragm (8a) defining an outer boundary of the first cavity (7) containing the pressure-transferring fluid
Implementation Method 2
a second cavity (10) containing a pressure-transferring fluid in pressure communication with the pressure sensing element (4), and a third separation diaphragm (8b) bounding the second cavity (10), with the third separation diaphragm (8b) being configured for pressure communication with the second separation diaphragm (8a)
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The present invention relates to a retrievable pressure sensor for the in situ measurement of pressure of a process fluid in a pipe/chamber, and to a method for retrieving the pressure sensor. The pressure sensor comprises a pressure- transferring arrangement (2) which includes a device for sealing attachment in an opening in a wall of the pipe/chamber, a cavity (7) containing a pressure- transferring fluid, a first separation diaphragm (5) for separating between the process fluid (3) and the pressure-transferring fluid, and a second separation diaphragm (8a) defining an outer boundary of the cavity (7) containing the pressure-transferring fluid. The pressure sensor further includes an outer sensor part having a pressure sensing element (4), a second cavity (10) containing a pressure-transferring fluid in pressure communication with the pressure sensing element (4), a third separation diaphragm (8b) bounding the second cavity, the third separation diaphragm (8b) being configured for pressure communication with the second separation diaphragm (8a) for transferring pressure between the pressure-transferring fluid in the cavity (7) and the pressure-transferring fluid in the second cavity (10).