MEMS Flow Controller with Pneumatic Diaphragm Actuation
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Solution Overview
Problem
Conventional flow controllers are complex, large in scale, and inefficient due to delayed response times, high power consumption, and difficulty in operating at low pressures, primarily due to the use of heat-sensitive coils and large elastic forces required for valve operation.
Innovation Solution
A flow controller design featuring a MEMS sensor for rapid flow rate detection, a diaphragm assembly displaced by pilot air, and a balanced structure to equalize pressing forces, allowing for low-pressure operation and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heat-sensitive coils are wound on a thin metal conduit for flow rate detection, then the flow rate can be detected, but a time lag is generated in the conduit when heat is transferred, resulting in delayed response time
Solution Approach 1:
The patent replaces the conventional heat-sensitive coil system with a flow-sensitive element that directly detects flow rate through pressure differential measurement. This mechanical substitution eliminates the thermal inertia and time lag inherent in heat transfer-based detection, achieving rapid response time while maintaining accurate flow rate measurement.
2Measurement precision
If heat-sensitive coils are wound on the conduit and welding is required for assembly, then the flow rate detector can be constructed, but the assembly operation becomes complex and manufacturing costs increase
Solution Approach 1:
The patent merges the flow-sensitive element directly with the body structure, integrating the detection function into the main housing. This integration eliminates separate assembly steps for mounting heat-sensitive coils and conduit welding, simplifying manufacturing while maintaining flow rate detection capability.
3Reliability
If a large elastic force is required for the return spring to place the valve body in a closed state, then the valve can be sealed properly, but the return spring must be made large in scale, increasing product size
Solution Approach 1:
The patent introduces a pilot air system that uses pneumatic pressure to assist the return spring in seating the valve body. The pilot air provides additional sealing force without requiring a large spring, enabling proper valve closure while maintaining a compact product size.
4Reliability
If a large elastic force is required for the return spring, then the valve body can be sealed, but the minimum operating pressure must be large, preventing operation at low pressures
Solution Approach 1:
The patent employs a pilot air mechanism that supplies controlled pneumatic pressure to the valve body seating surface. This external pneumatic assistance reduces the burden on the return spring, allowing the valve to seal reliably at low operating pressures without requiring a large spring force.
5Extent of automation
If a solenoid valve is disposed in the proportional valve for opening and closing the valve body, then the valve can be controlled electrically, but power consumption is increased and heat generated at the solenoid section may be transferred to the flow rate detector, affecting detection accuracy
Solution Approach 1:
The patent replaces the solenoid valve with a diaphragm-based pneumatic control system. This mechanical substitution eliminates the high power consumption and heat generation associated with solenoid operation, while maintaining automated control capability through pneumatic actuation of the valve body.
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 enables faster flow rate control with reduced power consumption, smaller device size, and efficient operation at low pressures, improving response time and reducing manufacturing complexity.
Implementation Method 1
the detection unit is constituted by a MEMS sensor
Implementation Method 2
a diaphragm assembly which is displaced by supply of pilot air
Implementation Method 3
a spring that urges the valve body in a direction to be seated on a valve seat
Data Source
AI summary
A flow controller includes a flow detection unit that includes a detection unit for detecting the flow rate of a fluid; and a flow control unit that is coupled to the flow detection unit and that is capable of adjusting the flow rate of the fluid. The detection sensor constituting the detection unit includes a thermal flow sensor using MEMS technology, and the flow rate of the fluid that has been detected by the detection sensor is output to a control unit. In addition, in the flow control unit, the supply state of air to a supply room is switched by each of a supply-use solenoid valve and an exhaust-use solenoid valve, and on the basis of the supply state of the air, a control valve opens and closes.