Fire Suppression Nozzle Seal Without O-Rings Under High Pressure
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Solution Overview
Problem
Water mist fire suppression systems with a 'wet pipe' configuration face challenges in maintaining a proper seal between the pressurized water in the supply conduit and the plug, leading to potential water leakage and damage due to deterioration of mechanical seals like O-rings, which are difficult to assess.
Innovation Solution
A nozzle design featuring a plunger with a protuberance that mates with a transversely extending interior landing in the fluid conduit, providing a seal without relying on O-rings, and distributing forces over multiple planes to withstand high pressures without compromising the heat-sensitive element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical gasket (O-ring) is used to seal between the plug and pressurized fluid conduit, then initial sealing is sufficient, but the seal deteriorates over time and is difficult to assess
Solution Approach 1:
The patent removes the O-ring gasket from the sealing system entirely. Instead of using a mechanical gasket that deteriorates over time, the invention creates a direct metal-to-metal seal between the plug surface and the fluid conduit surface, eliminating the component that causes reliability degradation.
Solution Approach 2:
The patent replaces the mechanical gasket-based sealing system with a heat-sensitive element-based sealing system. The heat-sensitive element (frangible bulb) maintains the seal until activated by heat, at which point it ruptures to allow plug movement and water discharge, providing both sealing and activation functions.
2Reliability
If a direct mechanical seal between plug and fluid conduit is used (as required by British Standard), then seal durability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent introduces a heat-sensitive element (frangible bulb) as an intermediary between the plug and the fluid conduit. This element serves as a mediator that maintains the seal during normal operation and provides a controlled failure mechanism when heat activation is required, reducing the precision requirements for direct plug-to-conduit mating surfaces.
3Productivity
If testing involves application of heat and/or immersion in liquid, then functional testing is achieved, but sealing components deform or disintegrate
Solution Approach 1:
The patent makes the heat-sensitive element the subject of the heat test rather than having the test affect a separate sealing component. The frangible bulb is designed to rupture at a specific temperature, and this rupture is the desired test outcome that confirms proper heat sensitivity. The element serves itself by being both the sealing mechanism and the heat-responsive activation mechanism.
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 ensures a reliable seal that withstands high pressures and maintains the integrity of the heat-sensitive element, preventing water leakage and enhancing the reliability of the fire suppression system.
Implementation Method 1
a heat-sensitive element configured to rupture in response to exposure to a temperature exceeding an activation temperature threshold
Implementation Method 2
the plugging end of the plunger profiled to mate with the downstream side of the interior landing, with the protuberance projecting through the passageway and beyond the upstream side of the interior landing, for providing a seal between the plunger and the fluid conduit
Data Source
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AI summary
A seal is provided between a plunger (209) and a fluid conduit (205) of a nozzle (101) for a water-based fire suppression system, in particular a water mist fire suppression system. The fluid conduit (205) is provided with an interior landing (301) extending transversely with respect to a longitudinal axis of the fluid conduit (205), the interior landing defining a passageway (302) extending therethrough between an upstream side (303) and a downstream side (304) of the interior landing (301). A plugging end (217) of the plunger (209) is provided with a protuberance (305) and a profile to permit mating with the downstream side (304) of the interior landing (301), such that, when mated, the protuberance (305) projects through the passageway (302) and beyond the upstream side (303) of the interior landing (301), to provide the seal.