Fluid Applicator Pressure Limiting Diaphragm
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Solution Overview
Problem
Conventional fluid applicators require a large force to operate due to high pressure requirements for the outlet valve, leading to unwanted fluid discharge and potential continuous flow issues, especially when the fluid supply is elevated or the viscosity varies.
Innovation Solution
The applicator incorporates a pressure limiting means with a flexible diaphragm and valve system that allows the outlet valve to open under lower pressure, preventing unwanted discharge by maintaining fluid pressure below ambient during the application stroke and using a one-way valve to control fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outlet valve is set to open only when there is a relatively large pressure in the barrel, then fluid discharge is controlled, but the required hand squeeze force becomes large and operator fatigue increases
Solution Approach 1:
The valve system is segmented into two distinct valves: an inlet valve and an outlet valve, each with separate control mechanisms. The outlet valve is controlled by a spring mechanism that responds to pressure changes, while the inlet valve is controlled by a diaphragm that responds to pressure differential. This segmentation allows independent optimization of each valve's opening pressure, enabling the outlet valve to maintain reliable discharge control while the overall system requires less hand squeeze force.
Solution Approach 2:
The invention changes the pressure parameter thresholds for valve operation. The outlet valve is designed to open at a lower pressure threshold than conventional applicators, reducing the required hand squeeze force. The spring constant and diaphragm stiffness are adjusted to establish appropriate pressure thresholds that balance discharge control with operational ease.
2Ease of operation
If the outlet valve opens at lower pressure to reduce hand squeeze force, then ease of operation improves, but unwanted fluid discharge may occur
Solution Approach 1:
The spring mechanism acts as an intermediary between the pressure source and the outlet valve. It mediates the pressure transmission by providing a controlled response threshold, ensuring the valve opens only when the spring force is overcome by the fluid pressure. This intermediary mechanism prevents unwanted discharge while allowing the valve to open at lower pressures for easier operation.
Solution Approach 2:
The invention replaces a purely mechanical rigid valve system with a spring-based compliant mechanism. The spring provides progressive resistance to valve opening, creating a more nuanced control system that can prevent unwanted discharge while requiring less force to operate. The elastic deformation of the spring allows for smoother pressure management compared to rigid mechanical stops.
3Quantity of substance
If the fluid supply container is held higher than the applicator, then fluid supply is improved, but continuous flow or dripping may occur when not in use
Solution Approach 1:
The valve system dynamically responds to changing pressure conditions. When the applicator is not in use, the spring mechanism and diaphragm maintain the valves in a closed state, preventing continuous flow even when the fluid supply container is elevated. During active use, the system dynamically transitions between valve states based on the applied pressure, allowing fluid supply while preventing unwanted flow.
Solution Approach 2:
The spring mechanism provides pressure feedback control. As fluid pressure builds in the barrel, the spring compresses and eventually opens the outlet valve when the threshold is reached. This feedback mechanism automatically regulates flow based on pressure conditions, preventing continuous flow from elevated containers while ensuring adequate supply during use.
4Reliability
If conventional one-way valves with springs are used, then fluid flow direction is controlled, but large pressure differences are required for valve operation
Solution Approach 1:
The invention extracts the spring mechanism from the traditional one-way valve design and applies it specifically to the outlet valve control. This allows the inlet valve to operate with minimal pressure differential using a simple diaphragm, while the outlet valve uses the spring to provide controlled resistance. The spring force is tuned to create the necessary pressure threshold for discharge control without requiring excessively large pressure differences overall.
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
This design reduces the required hand squeeze force, prevents unwanted fluid discharge, and maintains accurate dosing regardless of fluid height, viscosity, or discharge speed, while withstanding aggressive chemicals.
Implementation Method 1
The valves are typically biased with springs, so that they open only when there is a predefined difference in the fluid pressure between the upstream side of the valve and the downstream side
Implementation Method 2
The liquid to be dispensed is drawn into the barrel through an inlet via a one way inlet valve when the plunger is withdrawn inside the barrel
Implementation Method 3
During the discharge stroke, the outlet valve is pushed open by the raised fluid pressure within the barrel
Implementation Method 4
The valves are typically biased with springs, so that they open only when there is a predefined difference in the fluid pressure
Data Source
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AI summary
An applicator 102 has a fluid supply inlet (14), an outlet (4) and a barrel (1) having a barrel outlet (2) and a barrel inlet (15a). The barrel inlet (15) is in fluid communication, or selective fluid communication, with the fluid supply inlet (14). A one way outlet valve (3) is in fluid communication with the barrel outlet (2) and with the outlet (4). The applicator 100 has piston actuation means (32) for moving a piston (5) relative to the barrel (1). The applicator further comprises pressure limiting means (10) for limiting a maximum pressure of fluid entering the barrel (1) from the fluid supply inlet (14).