Coplanar Double-Membrane Differential Pressure Sensor for Overload Protection
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Solution Overview
Problem
Existing differential pressure sensors face challenges with high oil volume requirements, manufacturing costs, and potential corrosion points due to externally exposed bores, which compromise measurement accuracy and sensitivity.
Innovation Solution
A coplanar differential pressure sensor with a double membrane system and symmetrical capillary connections minimizes oil volume, ensures thermal decoupling, and provides effective overload protection by preloading membranes to prevent damage to the pressure-sensitive element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If externally exposed bores are used for oil filling in the measuring unit, then the measuring unit can be filled with hydraulic fluid, but corrosion points are created and manufacturing costs increase
Solution Approach 1:
The invention extracts the oil filling operation from the measuring unit by providing a separate filling chamber that is filled first, then connected to the measuring unit. This eliminates the need for externally exposed bores in the measuring unit, removing corrosion points and simplifying manufacturing while maintaining the ability to fill the hydraulic system.
Solution Approach 2:
The hydraulic system is segmented into two separate chambers: a filling chamber and a measuring unit. The filling chamber serves as an intermediate reservoir that can be filled independently through its own bore, then connected to the measuring unit via a connection piece. This segmentation allows the measuring unit to remain bore-free while still enabling oil filling.
2Volume of moving object
If the converter chamber is integrated into the measuring unit, then the overall device size is reduced, but the oil volume required increases
Solution Approach 1:
The invention segments the device into a measuring unit and a separate converter chamber that are spatially offset from each other. The converter chamber is positioned at a distance from the measuring unit and connected via capillary connections. This spatial separation allows the measuring unit to maintain its compact, bore-free design while the converter chamber serves as an external reservoir that minimizes the total oil volume required in the hydraulic system.
3Adaptability or versatility
If the pressure-sensitive element is exposed to high differential pressure, then the measurement range is increased, but the risk of chip destruction increases
Solution Approach 1:
The invention implements preliminary overload protection by positioning the separating membrane and its associated hydraulic pathway between the high-pressure source and the pressure-sensitive element. When excessive pressure is detected, the separating membrane deflects and activates the overload protection pathway before the pressure can reach and damage the pressure-sensitive element, thus protecting the chip while allowing normal high-pressure measurements.
4Quantity of substance
If coplanar double membrane system is used, then the oil volume is minimized, but thermal decoupling must be ensured
Solution Approach 1:
The invention segments the thermal pathways by spatially offsetting the converter chamber from the measuring unit and using thin-walled connection pieces for their connection. This segmentation creates thermal barriers that prevent heat from the converter chamber (which may contain heating elements or electronics) from coupling to the measuring unit and affecting the hydraulic fluid temperature, while maintaining the compact coplanar design that minimizes oil volume.
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 solution reduces oil volume, lowers measurement errors, and enhances manufacturing efficiency while ensuring robust overload protection, maintaining measurement accuracy and sensitivity.
Implementation Method 1
the pressures applied to the separating membranes are transmitted hydraulically to the pressure-sensitive element
Implementation Method 2
the overpressure is transmitted hydraulically from the high-pressure side to the low-pressure side such that the overpressure membrane and the separating membrane are deflected, and a hydraulic fluid displaced from the high-pressure side is received in the additional pressure chamber
Data Source
AI summary
A differential pressure sensor for determining the differential pressure between two pressures includes a converter chamber including a differential pressure measuring cell, and a measuring unit including a main body and a coplanar double-membrane system with two double membranes, each including a separating membrane and an overload membrane with a pressure chamber between the separating membrane and the overload membrane and an additional pressure chamber between the overload membrane and the main body. Each pressure chamber and each additional pressure chamber is paired with at least one capillary connection such that in the event of an overpressure, the overpressure is hydraulically transmitted from the high-pressure side to the low-pressure side via a hydraulic fluid such that the overload membrane and the separating membrane are deflected, and the hydraulic fluid displaced from the high-pressure side to the additional pressure chamber on the low-pressure side before the overpressure reaches the pressure-sensitive element.