Concealed Sprinkler Trigger Mechanism for Faster Activation

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Solution Overview

Problem

Existing fire protection sprinkler designs with fusible link trigger mechanisms face challenges in responsiveness and reliability due to the enclosure of the bottom outlet, which delays thermal energy penetration and affects the activation of the heat-sensitive agent.

Innovation Solution

A residential concealed sprinkler design featuring a yoke with a U-shaped crossbar and ejection structure made from stamped sheet metal, incorporating a glass bulb and compression screws to enhance the trigger mechanism's responsiveness and concealment, allowing for efficient fluid discharge when the glass bulb shatters due to heat from a fire.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the bottom outlet is entirely enclosed by the combined trigger and concealing mechanism, then concealment is improved, but thermal energy penetration is delayed and activation reliability deteriorates

Engineering Contradiction:
ImproveconcealmentVSAvoidactivation reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The enclosure is segmented into multiple sections: a main enclosure body and a separate outlet section with opening features. This segmentation allows the outlet to remain concealed during normal conditions while enabling thermal energy to penetrate through the opening features when fire occurs, resolving the contradiction between concealment and activation reliability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Opening features act as intermediaries between the enclosed outlet and the external environment. These features allow thermal energy to pass through the enclosure to activate the heat-sensitive agent while maintaining the concealed appearance of the outlet during normal conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the heat sensitive agent is located on the interior surface of the cover member, then concealment is improved, but thermal energy penetration time increases

Engineering Contradiction:
ImproveconcealmentVSAvoidactivation time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The heat-sensitive agent is pre-positioned on the interior surface of the cover member in a ready state. When thermal energy penetrates through the opening features, the agent is already in position to immediately respond, reducing activation time while maintaining concealment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical fusible links with a heat-sensitive agent that responds directly to thermal energy penetration. This substitution enables faster and more reliable activation while allowing for better concealment integration

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution provides a responsive and reliable fire protection sprinkler that efficiently activates fluid discharge upon reaching the preselected temperature, effectively suppressing fires with improved concealment and distribution patterns.

Implementation Method 1

thermal energy issued from the fire is constrained to pass in an upward direction from the outer surface of the cover member towards the heat sensitive compound

Methodology Applied
Scientific EffectThermal energy penetration: Conduction (thermal)

Implementation Method 2

a glass bulb that extends between the yoke and the closure element

Methodology Applied
Scientific EffectGlass bulb shattering: Thermal Shock

Implementation Method 3

a pair of sprinkler arms each include a radially inwardly extending leg extending toward one another and spaced from one another. The radially inwardly extending legs each include a threaded bore for receiving a compression screw

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3426357B1Residential concealed sprinkler
Publication Date: 2023.11.22 VIKING
  • EP3426357B1 patent drawingFigure 1
  • EP3426357B1 patent drawingFigure 2~4
  • EP3426357B1 patent drawingFigure 5~7

AI summary

An automatic fire protection sprinkler includes a sprinkler body having a passage with an inlet end and a discharge opening. A pair of sprinkler arms extend from the sprinkler body. The pair of sprinkler arms each include a radially inwardly extending leg including a threaded bore for receiving a compression screw. The pair of sprinkler arms each include a radially outwardly extending leg each defining an aperture therein. An outlet closure assembly includes a closure element that selectively blocks the discharge opening of the sprinkler body and a trigger assembly including a yoke that engages the compression screws and a glass bulb that extends between the yoke and the closure element. A deflector is coupled to the sprinkler arms by a pair of support pins that are received in the apertures in the radially outwardly extending legs of the at least two sprinkler arms.