Discharge Head Bellows Spring Layout for Stable Dose Return Force
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Solution Overview
Problem
Existing discharge heads for pharmaceutical liquids, particularly those intended for nasal application, face challenges in achieving high dosing accuracy and reliability while ensuring good recyclability, as plastic springs tend to relax over time, affecting the consistency of liquid dispensing.
Innovation Solution
A discharge head design featuring a fixed pump piston and a plastic bellows spring with an expanding shape, combined with a movable cylinder component, allows for consistent liquid discharge and high dosing accuracy. The design includes a 'lost motion' mechanism to counteract spring relaxation, ensuring reliable operation and efficient recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plastic spring is used instead of a metal spring, then recyclability is improved, but the restoring force decreases over time due to relaxation
Solution Approach 1:
The patent applies preliminary anti-action by designing a pump system that compensates for the expected relaxation of the plastic spring. The pump is configured to deliver a predetermined volume of liquid that accounts for the decreasing restoring force, ensuring consistent dosing performance throughout the product's lifecycle even as the spring relaxes.
Solution Approach 2:
The patent employs parameter changes by optimizing the plastic spring's geometric parameters (wire diameter, coil diameter, number of active coils) to achieve the desired force characteristics. By carefully selecting and adjusting these parameters, the spring maintains sufficient restoring force while remaining made of recyclable plastic material.
2Ease of manufacture
If the pump piston is fixed relative to the discharge head base, then manufacturing simplicity is improved, but the pump chamber volume control becomes more difficult
Solution Approach 1:
The patent applies segmentation by dividing the pump system into distinct functional components: a fixed pump piston integrated with the discharge head base, and a movable cylinder assembly. This segmentation allows the piston to be manufactured simply as a fixed component while the cylinder assembly provides the necessary volume control through its movement, resolving the contradiction between manufacturing simplicity and volume control precision.
3Manufacturing precision
If the cylinder component is movable relative to the discharge head base, then pump chamber volume adjustment is improved, but device complexity increases
Solution Approach 1:
The patent applies merging by combining the cylinder component with the liquid reservoir assembly, where the movable cylinder serves both as part of the pump mechanism and as the liquid containment structure. This integration reduces the number of separate components and simplifies the overall device architecture while maintaining the ability to adjust pump chamber volume through cylinder movement.
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 design achieves consistent liquid discharge quantity, maintains dosing accuracy despite spring relaxation, and facilitates easy recycling by using plastic components that can be processed in common recycling processes.
Implementation Method 1
a return spring in the form of a plastic bellows spring which, when the cylinder component is displaced in an actuating direction relative to the pump piston, exerts a counteracting return force on the cylinder component
Implementation Method 2
By reducing the size of the pump chamber, the liquid contained therein is pressurized and discharged through a discharge opening
Implementation Method 3
A dip tube may be provided integrally or as a separate component on the discharge head base, extending into the liquid reservoir
Data Source
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AI summary
The invention relates to a discharge head (10) for dispensing liquids, particularly pharmaceutical liquids. This discharge head (10) is designed to be attached to a liquid reservoir (100) and features a discharge head base (20) with a coupling device (22) for connecting to the liquid reservoir (100). It includes a discharge opening (86) and a pump device (40) for conveying liquid from the liquid reservoir (100) to the discharge opening (86), wherein the pump device (40) comprises a pump cylinder and a pump piston (32) that is at least temporarily guided in a sealing manner along a cylinder sliding surface (54). A design is proposed where the pump piston (32) is fixedly arranged relative to the discharge head base (20), and the pump cylinder is formed by a cylinder component (50) that is movable relative to the discharge head base (20). The discharge head is equipped with a return spring (90) designed as a plastic bellows spring, which exerts a counteracting return force on the cylinder component (50) when it is moved in an actuating direction (2A) relative to the pump piston (32).