Fluid Dispenser Pump Ferrule Sealing and Positioning
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Solution Overview
Problem
Fluid dispenser pumps, particularly 'atmospheric' types, face issues with fragile static sealing between the ferrule and piston, leading to leakage risks when stressed, and difficulty in accurately defining the rest position, which complicates manufacturing and assembly.
Innovation Solution
A fluid dispenser pump design where the ferrule cooperates leaktight with the actuator rod between the rest and intermediate positions, and non-leaktight between the intermediate and actuated positions, using a frustoconical junction and elastic contact zone to define the rest position accurately and prevent leakage, with a radial flange and axial sleeve for sealing, and made from flexible materials like LDPE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ferrule co-operates in leaktight manner with the piston to define rest position and prevent leakage, then sealing reliability is improved, but the static sealing becomes fragile and vulnerable to stress-induced leakage
Solution Approach 1:
The ferrule is designed to transition between static and dynamic sealing modes. In the rest position, the ferrule provides static leaktight sealing with the piston. During actuation, the ferrule dynamically transitions to a non-leaktight state, allowing venting while maintaining structural integrity under stress
Solution Approach 2:
The sealing parameter (leaktight vs non-leaktight) is changed based on the operational state. The ferrule co-operates in leaktight manner with the actuator rod during rest and intermediate positions, then transitions to non-leaktight co-operation during actuation, controlled by the position of the actuator rod relative to the ferrule's contact zone
2Measurement precision
If the rest position is defined by contact between piston and ferrule, then rest position definition is achieved, but deformation occurs during use leading to position drift
Solution Approach 1:
The function of defining the rest position is extracted from the piston-ferrule contact interface and relocated to the ferrule-actuator rod interface. The ferrule co-operates with the actuator rod to define the rest position, eliminating the piston-ferrule contact that caused deformation and position drift
Solution Approach 2:
The ferrule acts as an intermediary element between the actuator rod and the piston system. By having the ferrule co-operate with the actuator rod to define the rest position, the system achieves stable position definition without direct piston-ferrule contact that leads to deformation
3Reliability
If a sealing gasket is added to enable leaktight co-operation between ferrule and fastener ring, then sealing is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The sealing function is merged into the ferrule structure itself rather than being a separate gasket component. The ferrule's material properties and geometric design (including the contact zone with elastically deformable material) provide the sealing capability, eliminating the need for an additional sealing gasket between the ferrule and fastener ring
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
Substantially reduces leakage risks, maintains accurate rest position definition over time, and simplifies manufacturing and assembly by using a flexible ferrule and innovative sealing mechanisms.
Implementation Method 1
said contact zone is elastically deformed outwards when it co-operates in leaktight manner with said bottom portion of greatest diameter
Data Source
AI summary
A fluid dispenser pump (10) including a pump body (11) and a piston (20) that slides in leaktight manner in the pump body (11) between a rest position and an actuated position. The piston (20) is secured to an actuator rod (30) that extends axially out from the pump body (11). A ferrule (40) is mounted on the top edge (12) of the pump body (11), the ferrule (40) defining the rest position of the piston (20). The ferrule (40) co-operates in leaktight manner with the actuator rod (30) while the actuator rod (30) moves between the rest position and an intermediate position, and the ferrule (40) co-operates in non-leaktight manner with the actuator rod (30) while the actuator rod (30) moving between the intermediate position and the actuated position, so as to make it possible to vent the pump (10).