Valve Assembly for Precise Pipetting Pressure Control
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Solution Overview
Problem
Existing pipetting apparatuses face challenges in achieving precise dosing, particularly at low volumes, due to inadequate flow rate control and pulsations in pump pressure, leading to intermittent fluid dispensing and difficulty in maintaining exact volume.
Innovation Solution
A pipetting apparatus with a valve assembly that includes a valve device with a closure element moving relative to chamber openings, distributing pressure between a pipetting channel and a bypass channel to control flow resistance, allowing for precise adjustment of pipetting pressure and minimizing pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If throttle elements are used in the pressure and suction lines to limit flow rate, then dosing precision is improved, but pump pulsations continue to affect dosing accuracy and the system becomes highly limited in variability
Solution Approach 1:
The patent implements dynamic flow control through a valve mechanism that can be adjusted during operation. The valve needle can be positioned at different angles to dynamically change the opening cross-section area, allowing the system to adapt to different dosing requirements and pump conditions, thus resolving the contradiction between achieving precise dosing and maintaining system variability.
Solution Approach 2:
The patent changes the flow resistance parameter dynamically by adjusting the valve needle position. By varying the opening cross-section area of the throttle element, the system can optimize flow rate and dosing precision for different operating conditions, thereby maintaining both precision and adaptability.
2Productivity
If pump output is restricted to improve dosing control, then flow rate is reduced, but dosing becomes highly dependent on stroke frequency and pulsations continue to affect precision
Solution Approach 1:
The patent employs a valve mechanism that provides feedback control by allowing continuous adjustment of the opening cross-section area based on observed dosing performance. This enables real-time compensation for pump pulsations and stroke frequency variations, maintaining dosing accuracy while controlling flow rate.
Solution Approach 2:
The valve needle can be dynamically adjusted during operation to change the throttle opening, allowing the system to compensate for pump pulsations and maintain stable dosing despite variations in pump stroke frequency or output restrictions.
3Reliability
If fixed throttle settings are used before pipetting, then maximum pressure is limited to defined values, but the user must carefully consider which setting to make for each volume, reducing ease of operation
Solution Approach 1:
The patent replaces fixed throttle settings with a dynamically adjustable valve mechanism. The user can continuously adjust the valve needle position to achieve the desired pressure and flow rate for any given volume, eliminating the need to pre-select from discrete settings and significantly improving ease of operation while maintaining reliable pressure control.
4Device complexity
If conventional valve mechanisms are used to control flow rate, then structure is simplified, but exact dosing cannot be achieved particularly in low-volume pipettes
Solution Approach 1:
The patent enhances the conventional valve structure by implementing a needle valve mechanism with adjustable opening cross-section area. This dynamic adjustment capability allows for fine-tuned flow control that achieves exact dosing precision even for low-volume pipettes, while maintaining relatively simple overall device complexity.
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
Enables exact dosing independent of pipetting container size, reduces pulsations in pumping pressure, and allows for precise filling of low-volume containers, ensuring consistent dispensing of fluid samples.
Implementation Method 1
at least one pump device connected to at least one valve chamber in order to generate at least one chamber pressure in said valve chamber
Implementation Method 2
the chamber pressure is distributed to the pipetting channel and the bypass channel as a function of the position of the closure surface
Data Source
AI summary
The invention further relates to a method for producing said pipetting device. The invention relates to a pipetting device, in particular for pipetting a fluid sample by suctioning into a pipetting container using air under a pipetting pressure, having the following: —a valve assembly with at least one valve device for adjusting a pipetting pressure, said valve device having a valve chamber; —at least one pump device which is connected to the valve chamber in order to generate a chamber pressure in the valve chamber; —a pipetting channel which is connected to the pipetting container, and—a bypass channel which is open towards the surroundings, wherein—the pipetting channel and the bypass channel are each connected to the valve chamber; and—the at least one valve device has a closure element with a closure surface which is designed such that the chamber pressure is distributed to the pipetting channel and the bypass channel in a metered manner by the valve device in order to generate the desired pipetting pressure in the pipetting channel. The invention further relates to a method for producing said pipetting device.