Pipette Nozzle Assembly With Pressure Spring Sealing
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Solution Overview
Problem
Existing nozzle assemblies for pipettes face challenges in maintaining leakproofness, especially during incorrect mounting or slackening, and require difficult maintenance access for sealing means, limiting operational reliability and ease of use.
Innovation Solution
A two-piece nozzle assembly with a pressure sub-assembly comprising a pressure spring, locking sleeve, and cap allows automatic sliding of sealing means for easy maintenance access and independent pressure force adjustment, ensuring continuous leakproofness across pipette modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sealing means are integrated inside a one-piece nozzle, then the structure is simplified, but maintenance access to sealing means becomes difficult
Solution Approach 1:
The nozzle is divided into two separate pieces: the nozzle body and the holder. The sealing means (sealing ring and gasket) are positioned in the holder, allowing the holder to be removed independently for maintenance access while keeping the nozzle body intact. This segmentation resolves the contradiction by enabling easy maintenance of sealing components without complicating the overall nozzle structure.
2Ease of repair
If sealing pressure is achieved through a releasable thread connection between nozzle and holder, then maintenance access is improved, but leakproofness becomes unreliable under incorrect mounting or slackening
Solution Approach 1:
The pressure spring is configured to automatically maintain sealing pressure between the holder and nozzle without requiring manual adjustment or tight thread connections. The spring self-adjusts to compensate for mounting variations and prevents slackening, ensuring continuous leakproofness while allowing easy removal for maintenance. This eliminates the need for high-precision threading while maintaining reliable sealing.
3Ease of repair
If a two-piece nozzle assembly with detachable connection is used, then maintenance access to sealing means is improved, but the pressure force of sealing means becomes dependent on coupling accuracy
Solution Approach 1:
The sealing mechanism transitions from relying on precise dimensional parameters of thread connections to relying on the force parameter of a pressure spring. The spring's compressive force provides consistent sealing pressure independent of the exact positioning or dimensional tolerances of the detachable connection, thereby reducing manufacturing precision requirements while maintaining sealing effectiveness.
4Device complexity
If sealing means are compressed between holder and nozzle via thread connection, then assembly is simplified, but the sealing pressure cannot be independently adjusted
Solution Approach 1:
The static sealing pressure generated by thread connection is replaced with a dynamic pressure spring mechanism that can independently adjust sealing force. The spring's elasticity allows for variable pressure adjustment based on operational requirements, while the overall assembly remains relatively simple. This enables adaptability in sealing pressure without significantly increasing structural 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
The solution enhances operational reliability by ensuring continuous pressure and easy maintenance of sealing means, reducing the risk of leakproofness loss and damage, while allowing various sealing types and transparent holder observation for assembly/disassembly.
Implementation Method 1
a pressure spring (7) pressed via a pressure sub-assembly (6, 8, 10) to the sealing means (4, 5) positioned between the pressure sleeve (6) and the nozzle (3)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a nozzle assembly for mounting in a mechanical or an electronic pipette, which comprises a two-piece body consisting of a nozzle (3) and a holder (2), a plunger (1) cooperating by engaging means with a pipetting rod (18) of a pipette drawing up and discharging mechanism arranged in a pipette handle (16), and sealing means for sealing the plunger (1) in the nozzle assembly. The nozzle (3) is in its lower part formed respectively for receiving a pipette exchangeable tip (19) and is in its upper part releasably connected with the holder (2). In the holder (2) a pressure sleeve (6) is placed as being slidably borne in the holder (2). The pressure sleeve (6) is via a pressure sub-assembly seated in the holder (2) pressed to the sealing means placed between the pressure sleeve (6) and the nozzle (3). The plunger (1) is slidably borne in the pressure sleeve (6) and in the pressure sub-assembly. Due to this, leakproofness of the plunger (1) in the nozzle (3), which is indispensable for a correct and reliable pipette operation, is provided in PIPETTING, ADJUSTMENT or CALIBRATION MODES of the pipette. Simultaneously, in MAINTENANCE MODE of the pipette the sealing means automatically slide out from an abutting surface (2c) of the holder (2).