Metered Dose Valve Stem Integration for MDI Cost Reduction
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Solution Overview
Problem
Current metered dose inhaler (MDI) valves are costly and complex, leading to high manufacturing costs and performance issues such as poor pressure-filling performance, high firing forces, and leakage, which limits their acceptance in price-sensitive markets and affects the reliability of asthma treatment in developing countries.
Innovation Solution
A metered dose dispensing valve with a valve stem and second valve body integrated into a single component, combined with a separate compliant biasing member, allowing precise control of force characteristics and reducing the number of components, thereby simplifying assembly and improving compatibility with existing inhaler systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional multi-component valve design is used, then the valve can provide adequate sealing and metering functions, but the manufacturing cost increases and assembly complexity increases
Solution Approach 1:
The patent combines the valve stem and second valve body into a single integrally formed component, reducing the total component count from seven or eight parts to five parts. This merging eliminates the need for separate assembly of these components while maintaining the sealing and metering functions through carefully designed integrated features.
Solution Approach 2:
The integrally formed valve stem and second valve body component performs multiple functions simultaneously: it provides structural support, defines the pre-metering region, guides the valve stem movement, and interfaces with the biasing member. This multi-functionality reduces the need for separate dedicated components for each function.
2Reliability
If a conventional multi-component valve design is used, then the valve can provide adequate sealing and metering functions, but the manufacturing cost increases
Solution Approach 1:
The integration of the valve stem and second valve body into a single component reduces manufacturing cost by eliminating separate machining operations, material handling, and assembly processes for multiple parts. The integral design allows for more efficient production while maintaining the required sealing and metering performance.
3Device complexity
If components are reduced in number, then the manufacturing cost decreases and assembly simplifies, but the force characteristics control becomes less precise
Solution Approach 1:
The biasing member is designed with specific local characteristics including variable wire diameter along its length and particular winding patterns to precisely control the force characteristics. This localized optimization of the spring geometry allows accurate force control despite the reduced component count.
Solution Approach 2:
The patent optimizes the biasing member parameters including wire diameter, coil density, free length, and end configurations to achieve the desired force characteristics. By carefully selecting and adjusting these parameters, the single biasing member compensates for the reduced component count while maintaining precise force control.
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 manufacturing costs, minimizes performance issues, and enhances compatibility with industry-standard inhalers, providing a reliable and cost-effective valve for MDIs that can interface conventionally with aerosol containers, ensuring consistent dose delivery and reduced leakage.
Implementation Method 1
a compliant biasing member; and a valve stem passing axially through the metering chamber, movable relative to the chamber between non-dispensing and dispensing positions, and biased from its dispensing position towards its non-dispensing position by the compliant biasing member
Data Source
Figure 1~2
Figure 3a~4b
Figure 5~7
AI summary
A metered dose dispensing valve for dispensing metered dose volumes of an aerosol formulation from an aerosol container comprising: • a first valve body (213) defining in part a metering chamber (212); • a compliant biasing member (215); • a valve stem (214) passing axially through the metering chamber, movable relative to the chamber between non-dispensing and dispensing positions, and biased from its dispensing position towards its non-dispensing position by the compliant biasing member; and • a second valve body (230) defining a non-compliant portion (991) and a compliant portion (992).