Resonating Needle Fluid Dosage Control
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Solution Overview
Problem
Current systems for dosing small fluid quantities in advanced analytics and in-vitro diagnostics face challenges due to the compressibility of air, viscosity changes, and reactivity of fluids, making it difficult to accurately measure and deliver small volumes, especially less than 4 microliters, as traditional methods are prone to solidification and gas bubble formation.
Innovation Solution
A metallic resonating needle coupled with a piezoelectric resonating element is used to measure and control the dosage of small fluid quantities by detecting oscillation parameters, allowing for precise in-line measurement and control during collection and delivery, utilizing a laminar piezo-bender element to induce and detect flexural oscillations for accurate mass determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If volumetric pumps are used to deliver small fluid quantities, then fluid delivery capability is provided, but measurement precision deteriorates due to compressibility of air and inability to operate directly in contact with the fluid
Solution Approach 1:
The invention extracts the measurement function from the delivery system by using a separate resonating needle that directly contacts the fluid to be measured. This separate measurement path eliminates interference from air compressibility and allows direct fluid contact for accurate mass measurement, while the delivery pump handles only the transport function.
Solution Approach 2:
The resonating needle acts as an intermediary measurement tool between the delivery pump and the fluid. It provides direct contact with the fluid for accurate mass determination through resonance frequency changes, while being driven by an ultrasonic transducer that does not directly contact the fluid, thus avoiding contamination and maintaining measurement precision.
2Ease of operation
If traditional measurement methods (fluid flowmetry or weighing) are used for small fluid quantities, then measurement capability is provided, but measurement precision deteriorates due to small mass and difficulty in controlled delivery
Solution Approach 1:
The invention uses mechanical vibration at resonance frequency of the needle to enhance measurement sensitivity. The ultrasonic transducer drives the needle to vibrate, and changes in resonance frequency caused by fluid mass attachment are detected with high precision, enabling accurate measurement of microliter quantities that are too small for traditional methods.
Solution Approach 2:
The invention measures fluid mass by detecting changes in the resonance frequency parameter of the needle. As fluid mass is added to the needle, the resonance frequency shifts, providing a sensitive and accurate measurement method for small quantities that overcomes the limitations of traditional flowmetry and weighing techniques.
3Ease of operation
If piezoelectric components are used for delivery assistance, then delivery control is improved, but measurement capability is lost as the system cannot measure fluid quantities
Solution Approach 1:
The resonating needle system serves dual functions: it acts as both a delivery control mechanism (through ultrasonic vibration) and a measurement tool (through resonance frequency detection). This multi-functionality eliminates the need for separate measurement systems while maintaining accurate fluid quantity control and measurement capability.
Solution Approach 2:
The needle itself serves as the sensing element by using its own resonance characteristics to detect fluid mass. The system is self-measuring, as the needle's natural vibration properties change in response to fluid attachment, providing inherent measurement capability without requiring external sensors or complex measurement systems.
4Ease of operation
If small volumes of fluid are handled by volumetric pumps, then fluid delivery is provided, but reliability deteriorates due to solidification and gas bubble formation from pressure and temperature variations
Solution Approach 1:
The invention extracts the measurement and direct fluid contact function from the pump system. The resonating needle directly contacts the fluid for measurement and delivery control, while the pump operates separately without direct fluid contact, minimizing pressure and temperature variations that cause solidification and gas bubble formation.
Solution Approach 2:
The ultrasonic transducer applies periodic vibration to the needle at resonance frequency, creating controlled oscillatory motion for fluid delivery. This periodic action enables precise control of small fluid volumes without the continuous high-pressure conditions that lead to reliability problems in traditional pump systems.
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 enables continuous, high-accuracy measurement and control of small fluid masses, overcoming the limitations of traditional methods by accurately detecting mass variations and adjusting delivery to ensure precise dosing of microliter quantities, even in reactive and viscous fluids.
Implementation Method 1
a resonating element of the piezoelectric laminar type, coupled to said needle solely for the purpose of determining said oscillation, said resonating element being adapted to be energized in order to detect variations of oscillation parameters
Implementation Method 2
The needle can be seen as a beam fixed to its upper support point which, when subjected to flexural oscillation, will have a resonance frequency dependent on its rigidity and on the total oscillating mass
Data Source
AI summary
A resonating needle is adapted to be used in a device for measuring and controlling the dosage of a small quantity of fluid, includes: a needle (1) adapted to contain said small quantity of fluid; a resonating element of the piezoelectric type (2), coupled to said needle and adapted to be energized in order to detect variations of oscillation parameters of the needle and of the resonating element for the purpose of determining the dosage measurement and control.