Pressure-Compensated Fluid Sensor Casing for Mass Flow Control
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Solution Overview
Problem
Fluid sensing apparatuses in mass flow controllers face limitations due to their inability to withstand high internal pressures, leading to potential leakage and failure, particularly in miniature applications where robustness increases manufacturing complexity and cost.
Innovation Solution
A fluid sensing apparatus with a pressure compensation chamber and conduits that balance internal fluid pressure, reducing the burden on the sensor casing and allowing for the use of lighter, smaller, and less complex components by compensating for internal pressure with fluid from the same pressure source, thereby minimizing the risk of leakage and failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor casing is reinforced to withstand high internal pressures, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
A pressure equalization chamber is introduced as an intermediary space between the sensor casing and the high-pressure fluid flow. This chamber receives fluid at high pressure through a pressure equalization conduit, and the fluid pressure in this chamber acts on the external surface of the sensor casing to balance the internal pressure, thereby protecting the casing from high pressure differential without requiring complex reinforcement
2Reliability
If the sensor casing is reinforced to withstand high internal pressures, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The pressure equalization chamber serves as a mediator that decouples the sensor casing from direct exposure to high fluid pressure. By introducing this intermediate pressure-balancing system, the casing only needs to withstand minimal pressure differential, allowing use of standard, inexpensive casing materials and manufacturing processes rather than specialized high-pressure components
3Reliability
If the sensor casing is made robust to resist internal pressure, then reliability is improved, but the device size and weight increase
Solution Approach 1:
The pressure equalization chamber introduces a fluid-mediated pressure balancing system that eliminates the need for heavy-duty pressure-resistant casing materials. The chamber receives high-pressure fluid through a conduit and uses this fluid pressure to externally balance the internal pressure on the casing, allowing the use of lightweight casing construction while maintaining reliability under high operating pressures
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
This design enhances the reliability and compactness of fluid sensing apparatuses by reducing the pressure differential the casing must withstand, enabling their use in compact devices like miniature mass flow controllers while maintaining accuracy and simplicity in manufacturing.
Implementation Method 1
fluid can be supplied to the pressure compensation chamber via the at least one pressure compensation conduit so that the fluid pressure on the outside of the casing can be balanced with the fluid pressure inside the casing
Data Source
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AI summary
There is provided a fluid sensing apparatus (120) comprising a fluid flow channel (121), at least one fluid conduit (132, 134) in fluid communication with the fluid flow channel (121), and a fluid sensor (130) having a casing (131) and at least one sensor port (135, 136) in fluid communication with the at least one fluid conduit (132, 134) and providing access into the casing (137). The fluid sensing apparatus (120) also includes a pressure compensation chamber (142) in which the casing (137) of the fluid sensor (130) is enclosed. The apparatus further includes at least one pressure compensation conduit (144) in fluid communication with the pressure compensation chamber (142). Also provided is a mass flow controller (100) including such a fluid sensing apparatus.