Truncated Pipette Syringe Tip for Lower Fluid Drag
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Solution Overview
Problem
Positive displacement pipettes experience excessive fluid drag during dispensing operations, particularly at the bottom of the piston stroke, due to the piston tip entering the narrowest portion of the dispensing tip, which increases the required dispensing force and can lead to user fatigue or exceed the capacity of motorized mechanisms.
Innovation Solution
The design of a positive displacement pipette syringe with a truncated piston tip that minimally enters the dispensing tip, maintaining a consistent fluid passageway and reducing fluid drag by up to 67%, allowing for ergonomic operation and efficient use with both manual and motorized pipettes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the piston tip enters the narrowest portion of the dispensing tip to reduce air volume, then dispensing accuracy is improved, but fluid drag increases excessively
Solution Approach 1:
The piston tip length is changed from a conventional longer design to a truncated shorter design. This parameter change allows the piston to maintain sealing contact with the capillary wall while minimizing intrusion into the dispensing tip's narrowest portion, thereby reducing fluid drag during dispensing operations.
Solution Approach 2:
The piston tip is designed with truncated length specifically at the portion that contacts the dispensing tip, while the main piston body retains its sealing functionality. This local modification optimizes the interaction between the piston and dispensing tip, reducing fluid drag in the critical dispensing region without compromising overall piston function.
2Measurement precision
If the piston tip enters the dispensing tip to minimize air volume, then positive displacement accuracy is improved, but user fatigue increases due to excessive dispensing force
Solution Approach 1:
The piston tip length parameter is modified to a truncated design, which maintains the positive displacement mechanism's accuracy by preserving the seal between piston and capillary wall, while significantly reducing the force required during manual operation by minimizing obstruction of the fluid passageway.
3Measurement precision
If the piston tip enters the narrowest portion of the dispensing tip, then fluid displacement precision is improved, but motorized mechanism capacity is exceeded
Solution Approach 1:
The piston tip length is parameterized to a truncated configuration that preserves the precision fluid displacement capability through maintained sealing, while reducing the peak force requirements during dispensing to within the capacity of motorized dispensing mechanisms.
4Measurement precision
If the piston tip enters the dispensing tip to reduce air volume, then dispensing accuracy is improved, but fluid drag increases particularly at bottom of stroke
Solution Approach 1:
The piston tip length parameter is optimized to a truncated design that maintains adequate sealing for accurate dispensing while minimizing the obstruction of fluid flow path, particularly at the bottom of the stroke where conventional designs create maximum drag.
Solution Approach 2:
The piston tip is locally modified with truncated length at the dispensing interface, preserving sealing quality where needed while minimizing interference with fluid flow in the dispensing tip's narrowest portion.
Data Source
AI summary
Described are exemplary embodiments of a syringe for use with a handheld positive displacement pipette. The syringe includes a piston having a piston tip that is significantly truncated in comparison to the tips of known positive displacement pipette syringes, and also shorter in length than the dispensing tip of the syringe. The design of the piston tip and its interaction with the syringe dispensing tip results in a substantial reduction in the fluid drag associated with dispensing liquid from a typical positive displacement pipette syringe.