Ring Sealed Diaphragm Actuator Stem Seal
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Solution Overview
Problem
Existing diaphragm actuators for fluid process control devices require additional parts such as o-rings and hose-clamps, which increase assembly complexity and reduce reliability, and are typically configured for a single biased mode, necessitating a new actuator for changes in configuration.
Innovation Solution
The actuator design incorporates a housing with a concave and convex plate, a diaphragm, and a nut that compresses the diaphragm between housing components, providing a direct seal with the stem and eliminating the need for additional sealing parts, allowing for reversible configuration between biased-open and biased-closed modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional sealing parts such as o-rings and hose-clamps are used in diaphragm actuators, then fluid-tight sealing is achieved, but device complexity and assembly steps increase
Solution Approach 1:
The patent combines the sealing function with the diaphragm plate structure itself. The recess in the diaphragm plate directly receives and seals against the stem, eliminating the need for separate o-rings or hose-clamps. This merging of sealing functionality into the existing structural component reduces part count while maintaining fluid-tight sealing.
Solution Approach 2:
The patent extracts and eliminates unnecessary sealing components (o-rings, hose-clamps) from the traditional diaphragm actuator design. By designing the diaphragm plate with an integrated recess that directly engages the stem, the invention removes these additional parts while preserving the essential sealing function.
2Reliability
If additional sealing parts such as o-rings and hose-clamps are used in diaphragm actuators, then fluid-tight sealing is achieved, but assembly steps and manufacturing complexity increase
Solution Approach 1:
The sealing function is merged into the diaphragm plate structure through the recess feature. This eliminates the need for separate assembly steps involving o-rings or hose-clamps, as the recess directly engages with the stem to provide sealing in a single integrated operation.
Solution Approach 2:
The patent removes additional sealing components and their associated assembly steps from the manufacturing process. The integrated recess design allows for simpler assembly where the stem directly engages the recess without requiring separate installation of o-rings or hose-clamps.
3Device complexity
If diaphragm actuators are configured for a single biased mode, then structural simplicity is maintained, but adaptability to different operational configurations is reduced
Solution Approach 1:
The patent enables the actuator to dynamically switch between biased-open and biased-closed configurations through the reversible positioning of the diaphragm plate on the stem. This dynamic reconfigurability allows the same actuator structure to adapt to different operational requirements without requiring complete redesign or replacement.
Solution Approach 2:
The actuator design achieves multi-functionality by allowing the diaphragm plate to be positioned in different locations along the stem, enabling both biased-open and biased-closed modes. This universal design eliminates the need for separate actuators for different biasing requirements, enhancing versatility while maintaining structural simplicity.
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 reduces parts and assembly costs, enhances reliability by eliminating prone-to-failure components, and allows for easy switching between operational configurations without requiring new actuators.
Implementation Method 1
The actuator comprises a nut adapted to compress the diaphragm between the first and second housing components and between the outer radial portions of the concave and convex plates
Data Source
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AI summary
An actuator (10) for a fluid process control device (12), comprising: a housing (26) comprising a first housing component (32) and a second housing component (34); a diaphragm (56) comprising an outer radial portion (56a) and an inner radial portion (56b), the outer radial portion (56a) of the diaphragm (56) carried between the first and second housing components (32, 34), the inner radial portion (56b) comprising an inner opening (62) and a bead (64) that extends around a circumference of the opening (62); a stem (22) operatively coupled to the diaphragm (56) for controlling the fluid process control device (12), the stem (22) including a shoulder (22c) and a threaded end portion (22b); and a plate assembly (28) connecting the stem (22) and the diaphragm (56), the plate assembly (28) comprising a concave plate (154) and a convex plate (152) compressing the diaphragm (56) therebetween, wherein a threaded means threaded onto the threaded end portion (22b) compresses the plate assembly (28) against the shoulder (22c) and compresses and flattens the concave plate (154) and the convex plate (152), the plate assembly (28) applying a compressive load to the inner radial portion (56b) of the diaphragm (56) and providing a line of contact with the stem (22) to provide a fluid-tight seal between the plate assembly (28) and the stem (22), wherein the bead (64) of the diaphragm (56) is disposed within a circumferential cavity (175) formed between circumferential recesses (173) in the concave and convex plates (152, 154) to secure the diaphragm (56) against pulling out from between the concave and convex plates (152, 154); wherein the compressed and flattened configuration of the concave and convex plates (152, 154) applies a tensile load to a portion of the threaded end portion (22b) of the stem (22) at a location between the concave and convex plates (152, 154) to provide a fluid tight sealing engagement between the concave plate (154) and a shoulder surface (46) of the shoulder (22c) of the stem (22).