Metering Valve Longitudinal Splines Prevent Drainback
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Solution Overview
Problem
Retention-type metering valves often experience incomplete dose expulsion when stored upright, with fluid returning to the reservoir through the internal channel, leading to a loss of dose known as 'drainback'.
Innovation Solution
A metering valve design featuring a valve body with a cylindrical portion containing longitudinal splines that center the valve member, minimizing contact areas and maintaining fluid retention in a second chamber, connected to the metering chamber via an internal channel, ensuring reliable and complete dose dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve is stored in the upright position with the valve member above the reservoir, then the valve structure is compact and easy to store, but fluid returns to the reservoir through the internal channel causing incomplete dose expulsion
Solution Approach 1:
The invention introduces longitudinal splines that extend axially along the valve member, transforming a purely radial clearance issue into a three-dimensional geometry problem. The splines create multiple narrow radial gaps instead of one large gap, effectively using the axial dimension to control fluid flow paths and prevent drainback while maintaining compact upright storage capability
2Reliability
If the clearance between the valve member and valve body is reduced to prevent fluid return, then fluid retention improves, but manufacturing precision requirements increase
Solution Approach 1:
The invention divides the single large radial clearance between the valve member and valve body into multiple smaller clearances by introducing longitudinal splines. Instead of requiring one precise small gap, the system uses several gaps created by spline teeth, which are easier to manufacture with standard tolerances while achieving the same fluid retention effect
3Reliability
If the internal channel is made more complex to prevent fluid return, then dose retention improves, but device complexity increases
Solution Approach 1:
The invention extracts the fluid control function from the internal channel geometry and relocates it to the radial clearance zone between the valve member and valve body. The longitudinal splines create fluid barriers in the radial direction, allowing the internal channel to remain simple while achieving dose retention through the extracted geometric feature
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 design effectively prevents or slows down the emptying of the second chamber, maintaining fluid in the metering chamber and preventing 'drainback', ensuring consistent and reliable dose delivery.
Implementation Method 1
a valve member that slides axially in said valve body between a rest position and a dispensing position, for selectively dispensing the contents of said metering chamber; said valve member including a collar and being urged towards its rest position by a spring that co-operates firstly with said valve body and secondly with said valve member
Implementation Method 2
said valve-body cylindrical portion including a plurality of longitudinal splines that extend over at least a fraction of the height of said valve-body cylindrical portion, said longitudinal splines projecting radially inwards and acting on said collar of said valve member for substantially centering said collar in said valve-body cylindrical portion
Data Source
AI summary
A metering valve for dispensing fluid, the metering valve comprising: a valve body (10) containing a metering chamber (20); and a valve member (30) that slides axially in said valve body (10) between a rest position and a dispensing position, for selectively dispensing the contents of said metering chamber (20); said valve member (30) including a collar (320) and being urged towards its rest position by a spring (8) that co-operates firstly with said valve body (10) and secondly with said valve member (30), said valve body (10) including a valve-body cylindrical portion (15) in which said collar (320) of said valve member (30) slides between its rest and dispensing positions, said valve-body cylindrical portion (15) including a plurality of longitudinal splines (100) that extend over at least a fraction of the height of said valve-body cylindrical portion (15), said longitudinal splines (100) projecting radially inwards and acting on said collar (320) of said valve member (30) for substantially centering said collar (320) in said valve-body cylindrical portion (15).