Piezoelectric Jetting Dispenser Adjustable Valve Force
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Solution Overview
Problem
Jetting dispensers face challenges in accurately setting the force between the valve element and the valve seat, leading to inconsistent droplet formation and increased maintenance costs due to wear, as well as the need for high precision and expensive sensors for force adjustment.
Innovation Solution
A movable contact element within the jetting dispenser allows for adjustable force and position settings without altering the nozzle or valve element, using a threaded contact element and force limiting mechanisms like clutches or electromagnetic elements to ensure precise force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a biasing member is used to force the valve element against the valve seat, then the valve element is reliably sealed in the idle state, but the force cannot be adjusted leading to wear and inconsistent droplet formation
Solution Approach 1:
The patent transforms the static biasing force into a dynamic, adjustable force by replacing the spring with a weight-based gravity force system. The force can be adjusted by changing the mass of weights or their position, allowing the same mechanical structure to adapt to different force requirements without compromising sealing reliability.
Solution Approach 2:
The invention changes the physical parameter of force application from elastic deformation (spring) to gravitational force (weights). This parameter change enables continuous adjustment of the biasing force by varying mass or position, while maintaining consistent and reliable valve sealing through the stable nature of gravitational force.
2Manufacturing precision
If high precision sensors and adjustment mechanisms are used to set the force between valve element and valve seat, then droplet formation consistency is improved, but device complexity and cost increase
Solution Approach 1:
The patent employs a self-regulating gravity-based force application system where weights automatically provide a stable, adjustable biasing force without requiring sensors, electronic control, or complex adjustment mechanisms. The system self-adjusts through simple mechanical means, reducing device complexity while maintaining droplet formation consistency.
Solution Approach 2:
The invention replaces expensive, complex precision sensors and adjustment mechanisms with simple, inexpensive mechanical weights. These weights can be easily adjusted or replaced without requiring sophisticated instrumentation, significantly reducing device complexity and cost while achieving the desired force precision.
3Device complexity
If the contact element is fixed in position, then the structure is simple, but the force on the valve element cannot be adjusted increasing maintenance costs
Solution Approach 1:
The patent makes the previously fixed contact element dynamic by linking it to an adjustable weight system. The contact force can now be adjusted by changing weight position or mass, extending the service life of the valve element and reducing maintenance frequency without significantly increasing structural complexity.
Solution Approach 2:
The invention allows preliminary adjustment of the biasing force through weight positioning before operation begins. This preliminary setup optimizes the valve contact force for extended service life and consistent performance, reducing the need for frequent maintenance and repairs during operation.
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 solution simplifies the adjustment process, reduces maintenance costs by allowing in-place force adjustments, and prevents over-tightening, ensuring consistent droplet formation and extended part life without the need for high-precision components or sensors.
Implementation Method 1
a piezo actuator engaging the actuation lever for pivoting the actuation lever
Implementation Method 2
a biasing member acting on a contact element for forcing the valve element against the valve seat
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a jetting dispenser (1) comprising a fluid chamber (6), a fluid inlet (8) to the fluid chamber (6), a fluid outlet (9) from the fluid chamber (6), and a valve seat (10) positioned between the fluid inlet (8) and the fluid outlet (9); a valve element (18); a piezoelectric drive assembly (30) configured to reciprocally move at least a portion of the valve element (18) relative to the valve seat (10); the drive assembly (30) comprising a biasing member (42) acting on a contact element for forcing the valve element (18) against the valve seat in an idle state, the contact element being arranged for contact with the valve element (18), an actuation lever (34) engaging the contact element (60, 80), a piezo actuator (32) engaging the actuation lever (34) for pivoting the actuation lever (34) such that the contact element is moved and the valve element (18) is free to disengage the valve seat (10), and an adjustment device for adjusting the position of the contact element (60, 80) such that a force acting on the valve element (18) in the idle state is adjustable.