Fusible Safety Valve for Oxygen Line Fire Shutoff

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Solution Overview

Problem

The use of oxygen delivery apparatus for patients with respiratory disorders poses a significant fire hazard due to the risk of oxygen leakage and ignition, especially in domestic environments where supervision is lacking, and existing safety valves are not adequately designed to prevent fires or cause discomfort.

Innovation Solution

A safety valve unit is integrated into the gas delivery apparatus, featuring a heat-sensitive fusible retainer and a resiliently-biased valve mechanism that closes the flow path in case of a fire, while being lightweight and easily accessible for checking and replacement, ensuring the apparatus does not weigh down on the supply line or cause patient discomfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a safety valve is integrated into the gas delivery apparatus, then fire safety is improved, but the device complexity increases

Engineering Contradiction:
Improvefire safetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The safety valve is integrated directly into the gas delivery apparatus by connecting the valve body to the flexible plastic tubing, merging the safety function with the existing delivery system. This integration provides fire safety protection while maintaining a compact and relatively simple overall device structure.

Inventive Principle:
Principle #5Merging (Combining)

2Speed

If a safety valve unit is connected close to the mask or nasal cannula, then fire response speed is improved, but the weight causes patient discomfort

Engineering Contradiction:
Improvefire response speedVSAvoidpatient comfort
Core Design Contradiction:
SpeedVSWeight of moving object

Solution Approach 1:

The safety valve utilizes a fusible link mechanism that dynamically responds to temperature changes. Under normal conditions, the valve remains closed and lightweight. When fire is detected (temperature rise), the fusible link melts and the valve automatically opens to stop gas flow, providing rapid fire response without adding significant weight during normal use.

Inventive Principle:
Principle #15Dynamics

3Difficulty of detecting and measuring

If the safety valve includes a fusible link mechanism, then automatic fire detection capability is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvefire detection capabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSEase of manufacture

Solution Approach 1:

The fusible link is designed to change its physical state (melt) at a specific temperature threshold, providing automatic fire detection. This approach uses a simple material property change rather than complex sensors or electronics, making the manufacturing process relatively straightforward while achieving effective fire detection capability.

Inventive Principle:
Principle #35Parameter changes

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 safety valve effectively isolates the gas supply from potential fires, reducing the risk of catastrophic conflagrations and ensuring patient safety by quickly cutting off oxygen flow in case of ignition, while being inexpensive, easy to install, and non-discomforting for the patient.

Implementation Method 1

The valve member is retained in the hollow body by a fusible retainer

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

The valve includes a spring which biases the shuttle towards a 'valve closed' position

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2102538B1Safety valve
Publication Date: 2021.08.04 BPR MEDICAL
  • EP2102538B1 patent drawingFigure 1
  • EP2102538B1 patent drawingFigure 2~3
  • EP2102538B1 patent drawingFigure 4~5

AI summary

Apparatus for use in delivery of gas capable of combustion that incorporates a safety valve unit (37). The safety valve unit (37) closes the flow path of the gas from the source upon occurrence of a fire. The safety valve unit (37) has a valve body (56), a valve head (65) resiliency biased towards a valve-closure position and a fusible retainer (73) that holds the valve member in a valve open position. The valve body (56) defines a fluid flow passage between an outlet and the valve head (65). Within the fluid flow passage there is an elongate link member (66) which extends from the valve head (65) to the foot (67). The foot (67) engages the fusible retainer (73).