Foam Aspiration Nozzle Air Inlet Shield Design
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Solution Overview
Problem
Existing foam-type portable fire extinguishers using non-AFFF foaming agents struggle to produce foams that are as effective as those produced by AFFF compounds, due to unsuitable nozzle designs.
Innovation Solution
A foam aspiration nozzle is designed to introduce air into a mixture of water and non-AFFF foaming agent, featuring a barb portion for connection to a supply hose, an inlet tube, outlet orifices, and air inlets along a tubular shaft, optimized to produce effective foams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing nozzles are used with non-AFFF foaming agents, then the foaming agent can be dispensed, but the foam produced does not exhibit effective fire suppressant characteristics
Solution Approach 1:
The nozzle design has been modified with specific geometric parameters including a 30-50 degree outlet orifice tilt angle converging at a focal point, optimized air inlet positioning, and specific orifice dimensions. These parameter changes enable the nozzle to effectively atomize and mix non-AFFF foaming agents with air to produce fire suppressant foam, resolving the incompatibility between existing nozzle designs and non-AFFF foaming agents while achieving reliable fire suppression effectiveness
2Reliability
If air aspiration is increased to improve foam quality, then foam suppressant effectiveness improves, but the risk of blocking air inlets increases
Solution Approach 1:
A guard collar portion is introduced as an intermediary protective element that surrounds the air inlet portion. This guard collar prevents debris, fingers, or other objects from blocking the air inlets while maintaining the optimized air aspiration geometry needed for effective foam production. The guard collar thus protects the air inlet system without compromising the foam suppressant effectiveness
3Reliability
If outlet orifices are angled to converge at a focal point, then foam production effectiveness improves, but manufacturing precision requirements increase
Solution Approach 1:
The design specifies a practical angle range of 30-50 degrees for the outlet orifices rather than a single precise angle, and defines the convergence focal point in terms of relative positioning rather than absolute precision. This parameter specification approach maintains foam production effectiveness while accommodating normal manufacturing tolerances, resolving the contradiction between effectiveness and manufacturability
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 nozzle effectively produces foams from non-AFFF foaming agents that are as effective or more effective than previous AFFF compounds, providing enhanced fire suppression capabilities.
Implementation Method 1
The introduction of air (aspiration) during the expulsion of the foaming agent/water mixture from the extinguisher causes the foaming agent to expand into a foam
Implementation Method 2
the pressure is used to expel a suppressant from a storage chamber through an exit to extinguish a flame
Data Source
AI summary
A foam aspiration nozzle for use with fire extinguishers. The foam aspiration nozzle includes a discharge tube having air inlets that are partially protected by a shield to prevent blockage, the shield having an open end to allow the entry of air. The foam aspiration nozzle also includes a spray flange which is configured with spray orifices that direct a water and foaming agent into the discharge tube where the water and foaming agent is mixed with air from the air inlets. The result of spraying the water and foaming agent such that air is introduced to the mixture is the production of foam which is expelled from the discharge tube for application to a burning substance to extinguish flames emanating from the substance.