Metering Valve Chamber Insert Design for Propellant Swelling
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Solution Overview
Problem
Existing metering valves experience seal behavior modifications and potential blockages due to changes in propellants, requiring new seal materials and extended development times, while also facing environmental concerns with current propellants like HFA-134a and HFA-227, which are harmful.
Innovation Solution
A metering valve design with a chamber insert featuring a cylindrical wall and annular seals, where the upper edge has a rectangular annular cutout and the lower edge has a radially extended flange, maintaining consistent seal contact surfaces and dimensions regardless of the chamber volume, allowing for reliable operation with less harmful propellants like HFA-152a or HFO1234ze without modifying seal materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the propellant is changed from CFC-based to HFA-134a/HFA-227, then environmental performance is improved, but seal behavior is modified causing swelling and potential blockages
Solution Approach 1:
The invention changes the physical parameters of the metering chamber by introducing a variable volume chamber defined by a movable piston. This allows the same seal materials to function reliably across different propellant types by adjusting the chamber volume rather than changing seal materials, thus resolving the contradiction between environmental improvement and operational reliability
Solution Approach 2:
The metering chamber is designed with a movable piston that dynamically adjusts the chamber volume. This dynamic structure compensates for seal swelling caused by different propellants, maintaining reliable valve operation with environmentally friendly propellants like HFA-134a and HFA-227 without requiring new seal materials
2Object-affected harmful factors
If the propellant is changed to HFA-152a or HFO1234ze, then environmental performance is improved, but seal swelling increases causing blockages and greater actuation force
Solution Approach 1:
The invention adjusts the metering chamber volume parameter to compensate for increased seal swelling. By varying the chamber volume through piston movement, the system maintains proper seal contact and reduces actuation force requirements when using propellants like HFA-152a or HFO1234ze, resolving the contradiction between environmental improvement and force requirements
3Adaptability or versatility
If the insert width is modified to change metering chamber volume, then dosing flexibility is improved, but seal behavior is modified causing deformation and swelling
Solution Approach 1:
Instead of modifying the static insert width, the invention uses a dynamic piston mechanism to vary the metering chamber volume. This maintains consistent seal contact surfaces and geometry, preserving seal performance while achieving dosing flexibility through controlled piston movement rather than insert modification
Solution Approach 2:
The invention separates the volume control function from the seal contact surface. The piston divides the chamber into variable volume sections while maintaining a separate, consistent seal interface, allowing dosing flexibility without compromising seal behavior
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
Ensures consistent valve seal behavior and reliable operation across varying volumes and propellants, reducing production and assembly line modifications, and mitigating swelling issues, thus preventing blockages and actuation force increases.
Implementation Method 1
a valve sliding axially in said valve body between a rest position and a dispensing position, to selectively dispense the contents of said metering chamber, said valve being urged towards its rest position by a spring that cooperates, on the one hand, with said valve body and on the other hand, with said valve
Data Source
AI summary
Metering valve for dispensing a fluid product, having a valve body containing a metering chamber defined by a chamber insert and two annular seals, a valve seal and a chamber seal. The chamber insert has a cylindrical wall, an upper edge cooperating with the valve seal and a lower edge that cooperates with the chamber seal. A valve slides axially in the valve body between a rest position and a dispensing position, so as to selectively dispense the contents of the metering chamber, the valve being urged towards its rest position by a spring that cooperates with the valve body and with the valve. The upper edge of the chamber insert has an annular cutout formed on the radially inner side of the upper edge, so that the width of the upper edge in contact with the valve seal is always the same, whatever the width of the cylindrical wall.