Liquid Level Sensing Using Phase-Controlled Fields
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Solution Overview
Problem
Existing liquid level sensing systems in clinical chemistry and immunoassay diagnostics face challenges in accurately detecting liquid levels in both open and closed containers, particularly when using pipetting systems, as they often interfere with the signal emitted by the pipetting probe and can cause damage to the piercing cannula.
Innovation Solution
The implementation of a liquid level sensing apparatus that uses a phase-lock loop control system to maintain signal integrity by energizing the pipetting probe and cannula with electrically phase-controlled signals, allowing the cannula to pierce closed containers without degrading the signal emitted by the probe, and employing a signal analyzer to differentiate between the probe and cannula signals for accurate liquid detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pipetting probe is used to detect liquid level in a container, then liquid level detection capability is provided, but the probe interferes with the signal emitted by the pipetting probe itself
Solution Approach 1:
The patent introduces an antenna as an intermediary component that receives the electromagnetic signal emitted by the pipetting probe. The antenna is positioned to receive signals without the probe itself being in direct contact with the liquid, thereby mediating between the probe's signal emission and the liquid level detection function, eliminating self-interference.
2Reliability
If a cannula is used to pierce closed containers for sample access, then container sealing integrity is maintained, but the cannula degrades or interferes with the pipetting probe signal
Solution Approach 1:
The antenna serves as an intermediary that receives signals from the pipetting probe through the cannula structure without being directly affected by it. This allows the cannula to maintain its function of piercing closed containers while the antenna mediates the signal transmission, preventing the cannula from degrading the signal.
3Measurement precision
If the pipetting probe is positioned directly in the container to detect liquid level, then detection capability is improved, but the probe cannot differentiate between signal changes caused by liquid contact versus cannula presence
Solution Approach 1:
The antenna acts as an intermediary that receives electromagnetic signals and allows the system to differentiate between liquid contact and cannula presence. By positioning the antenna to receive signals without direct probe-liquid contact, the system can distinguish signal changes caused by liquid dielectric properties from those caused by the cannula structure.
Solution Approach 2:
The patent replaces direct mechanical contact-based liquid level detection with electromagnetic field-based detection using an antenna. This substitution allows for non-contact signal reception, enabling the system to detect liquid levels without the mechanical probe directly interfering with or being affected by the detection process.
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 precise liquid level detection and consistent aspiration or removal of fluid volumes from containers, preventing signal interference and cannula degradation, and is applicable to both open and closed containers.
Implementation Method 1
liquid level sensing systems may include a pipetting system employing a pipetting probe to aspirate a liquid from a container... the liquid level sensing systems may include a phase-lock loop control system... to cause the probe to emit a signal and receive the signal with an antenna positioned adjacent the container
Implementation Method 2
the liquid level sensing systems may include a phase-lock loop control system to maintain signal integrity by energizing the pipetting probe and cannula with electrically phase-controlled signals
Data Source
AI summary
Liquid level sensing apparatus and related methods are disclosed. An example method includes moving a cannula to pierce a seal of a container to provide access to a liquid in a cavity of the container; moving a probe through a passageway of the cannula and into the cavity of the container; and when the probe is at least partially positioned in the cannula: providing a first signal to the probe to cause the probe to emit a first electrical field; and providing a second signal to the cannula to cause the cannula to emit a second electrical field.