Bellows Diaphragm Assembly for Compact High-Flow Control
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Solution Overview
Problem
Mass flow controllers with smaller footprints face challenges in maintaining large deflection capabilities due to smaller diaphragm diameters, limiting their ability to regulate mass flow rates effectively in applications requiring higher flow rates.
Innovation Solution
A mass flow controller design featuring a diaphragm assembly with multiple convolutions, or bellows, that allows for larger deflections at smaller diameters, coupled with a push rod and poppet mechanism that enables opening and closing of the flow path, potentially eliminating the need for conventional springs and protecting components from gas exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diaphragm diameter is reduced to achieve a smaller footprint, then the device size is reduced, but the deflection capability is insufficient for high flow rate applications
Solution Approach 1:
The diaphragm is segmented into multiple convolutions (typically 3-7 bellows sections) along its length. This segmentation allows the diaphragm to achieve larger total deflection through the cumulative effect of multiple convex and concave sections, enabling high flow rate control in compact devices with smaller diameter diaphragms.
2Device complexity
If conventional springs are used in the control valve assembly, then the valve mechanism is simpler, but components are exposed to gas causing corrosion and degradation
Solution Approach 1:
The spring is extracted from the control valve assembly and replaced with a magnetic force field generated by the actuator. This eliminates physical contact between spring components and the process gas, preventing corrosion and degradation while maintaining the necessary restoring force for valve operation.
Solution Approach 2:
The mechanical spring system is replaced with a magnetic field-based actuation system. The actuator uses magnetic forces to control the poppet and valve operation, eliminating the need for mechanical springs that would be exposed to corrosive gases.
3Length of moving object
If larger diameter diaphragms are used to achieve sufficient deflection, then the deflection capability is adequate, but the device footprint increases
Solution Approach 1:
Instead of using a single large diameter diaphragm, the invention uses multiple convolutions of a smaller diameter diaphragm. The cumulative deflection of multiple bellows sections (each contributing a portion of the total deflection) achieves the required total deflection while maintaining a compact footprint.
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 reliable mass flow control at higher flow rates (up to 20 SLM) with smaller diaphragm diameters (7-9 mm), preventing corrosion and degradation of components, and allowing for more compact and reliable mass flow controllers.
Implementation Method 1
an actuator configured to move in response to the actuator control signal
Implementation Method 2
side walls extending from the aperture and disposed about a central axis, the side walls including multiple convolutions
Data Source
AI summary
A diaphragm assembly for a mass flow controller is disclosed. The diaphragm assembly includes an aperture, side walls extending from the aperture and disposed about a central axis, the side walls including multiple convolutions, and a poppet including an interior surface facing the aperture and exterior sealing surface. At least a portion of the diaphragm assembly moveable extends and retracts within a control valve cavity of the mass flow controller. A push rod extending from the interior surface of the poppet moves, responsive to an actuator of the mass flow controller, to enable the exterior sealing surface of the poppet to open and close a flow path through the control valve cavity.