Oil-Less Pressure Sensor With Mechanical Overpressure Stop
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Solution Overview
Problem
Conventional differential pressure sensors are limited by the material properties of incompressible liquid fluids, restricting their use in high-temperature and radiation-exposed environments.
Innovation Solution
A differential pressure sensor design that utilizes a load cell, sealed bellows, and a mechanical overpressure stop to detect pressure changes without an internal incompressible fluid, allowing operation in extreme conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional differential pressure sensors use incompressible liquid fluid for process isolation and overpressure protection, then overpressure protection is provided, but the maximum operating temperature is limited by material properties of the fluid
Solution Approach 1:
The patent removes the incompressible liquid fluid from the sensor system entirely. The bellows is designed to operate without any internal fluid filling, eliminating the temperature limitations imposed by fluid material properties while maintaining structural integrity through the bellows' own mechanical design
Solution Approach 2:
The patent replaces the expensive, temperature-limited incompressible fluid with a simple, solid mechanical overpressure stop that can withstand extreme temperatures. The stop acts as a sacrificial mechanical element that protects the load cell by physically limiting bellows expansion under overpressure conditions
2Reliability
If incompressible liquid fluid is used for process isolation, then process isolation is achieved, but application in high-temperature and radiation-exposed environments is restricted
Solution Approach 1:
The patent extracts the process isolation function from the incompressible fluid and implements it through the sealed bellows structure itself. The bellows acts as a physical barrier that isolates the process side from the measurement side, eliminating the need for temperature-sensitive fluid media
Solution Approach 2:
The patent employs composite material construction for the bellows, combining materials with high temperature resistance and radiation hardness. This allows the bellows to function as both the process isolation barrier and the structural element that can withstand extreme environmental conditions
3Reliability
If mechanical overpressure stop is added to limit bellows expansion, then load cell protection from overpressure damage is achieved, but device complexity increases
Solution Approach 1:
The mechanical overpressure stop is designed to be self-regulating and requires no external control systems. When overpressure occurs, the bellows naturally expands until it contacts the stop, which automatically limits further expansion and protects the load cell without requiring sensors, controllers, or active monitoring
Solution Approach 2:
The patent uses the flexible bellows shell itself as the primary overpressure sensing and protection mechanism. The bellows' inherent flexibility allows it to expand under pressure until the mechanical stop engages, creating a simple yet effective protection system that leverages the existing structural component rather than adding complex external protection mechanisms
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 operation in high-temperature and radiation-exposed environments by preventing damage to the load cell through mechanical engagement of the overpressure stop, maintaining sensor functionality.
Implementation Method 1
A bellows within the cavity is configured to expand and contract responsive to changes in pressure at the pressure port
Implementation Method 2
a load cell configured to generate signal indicating a magnitude of a pressure applied to the bellows
Data Source
AI summary
A pressure sensor includes a housing having an internal cavity, a pressure port, and a hole through which pressure is communicated between the pressure port and the internal cavity. A bellows within the cavity is configured to expand and contract responsive to changes in pressure at the pressure port. The pressure sensor additionally includes a load cell configured to generate signal indicating a magnitude of a pressure applied to the bellows, a moveable stop engagement member mechanically coupled to the bellows, and a mechanical overpressure stop that limits expansion of the bellows by mechanically engaging the moveable stop engagement member.