Flexible Bellows Seal for Liquid Dispensing Module
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional liquid dispensing devices face issues with dynamic seals causing friction and wear, leading to increased pressurized air requirements and potential leaks, as well as inadequate sealing over time.
Innovation Solution
A dispensing module with a flexible seal that moves with the needle between open and closed positions, eliminating the need for dynamic seals between moving surfaces, and utilizing a static seal between the needle guide and the dispenser body to prevent liquid leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dynamic seal is placed between the dispenser body and the moving valve stem to prevent liquid leakage, then sealing effectiveness is improved, but friction and seal wear increase
Solution Approach 1:
The sealing function is segmented into two distinct locations: a static seal between the dispenser body and needle guide, and a flexible membrane seal that moves with the needle. This segmentation allows the primary sealing burden to fall on the static seal, freeing the moving interface from high-friction dynamic sealing requirements.
Solution Approach 2:
The harmful dynamic sealing function is extracted from the moving needle interface and relocated to a stationary position. The static seal between the dispenser body and needle guide handles the primary sealing, while the needle moves freely through a flexible membrane that flexes rather than frictionally contacts the needle.
2Reliability
If a tight dynamic seal is used to prevent liquid leakage, then sealing effectiveness is improved, but pressurized air requirements increase due to higher friction
Solution Approach 1:
The sealing function is segmented into static and flexible components, placing the high-friction sealing burden on a stationary interface rather than a moving one. This reduces the force required to move the needle, thereby reducing pressurized air requirements.
Solution Approach 2:
A flexible membrane acts as an intermediary between the needle and the dispenser body. This membrane flexes to accommodate needle movement while maintaining the seal, eliminating the need for high-friction dynamic sealing and reducing the pressurized air force needed to move the needle.
3Use of energy by moving object
If a loose dynamic seal is used to reduce friction, then pressurized air requirements are reduced, but sealing effectiveness deteriorates allowing liquid to bind the piston
Solution Approach 1:
The sealing function is divided between a static seal that provides the primary sealing barrier and a flexible membrane that maintains sealing during needle movement. This segmentation ensures reliable sealing without requiring high-friction dynamic seals, thus avoiding liquid binding issues.
Solution Approach 2:
The critical sealing function is extracted from the moving needle interface and placed at a stationary location where a static seal can provide reliable sealing. This eliminates the trade-off between seal tightness and friction, as the static seal provides tight sealing without affecting needle movement friction.
4Reliability
If a dynamic seal is used to prevent liquid leakage, then sealing effectiveness is improved, but the seal wears over time losing its ability to seal properly
Solution Approach 1:
The sealing system is segmented into a static seal that handles the primary sealing function and a flexible membrane that accommodates movement. The static seal, being stationary, experiences no wear from needle movement, thereby dramatically extending seal life while maintaining sealing effectiveness.
Solution Approach 2:
The wear-inducing dynamic sealing function is extracted from the system and replaced with a static seal arrangement. The needle moves through a flexible membrane that flexes without frictional contact, eliminating the wear mechanism that would otherwise cause seal degradation over time.
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 flexible seal effectively prevents liquid leakage and reduces friction, allowing for efficient and reliable liquid dispensing with reduced pressurized air requirements and improved durability by eliminating dynamic seal-related issues.
Implementation Method 1
a flexible seal having a first and second end with the first end coupled to the needle guide and the second end coupled to the needle. The second end is adapted to move with the needle as it reciprocates.
Implementation Method 2
The needle moves relative to the needle guide between the open and closed positions. To prevent liquid from leaking out of the flow channel, the module includes a flexible seal having a first and second end
Data Source
AI summary
A dispensing module for dispensing liquid includes a dispensing body having an inlet, a discharge outlet, and a flow channel therebetween having a valve seat. A needle having a valve element is mounted to the body and reciprocates therein between an open position, in which the valve element is disengaged from the valve seat thereby allowing liquid flow, and a closed position, in which the valve element is engaged with the valve seat thereby preventing liquid flow. A needle guide is mounted to the dispenser body and includes a passage for receiving a portion of the needle. A flexible seal includes a first end coupled to the needle guide and a second end coupled to the needle and moving therewith. An actuator is operatively coupled to the needle and moves the needle between the open and closed positions. The seal includes a central portion with an interior cavity that stretches and compresses as the needle reciprocates.