Sealed Cartridge Head Assembly for Oxidation-Free Refilling

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Solution Overview

Problem

Pressurized gas cartridges in fire prevention devices suffer from premature wear and oxidation due to mechanical and chemical stresses, particularly during refilling operations, leading to electrolytic reactions and degradation of the cartridge neck and filling channels.

Innovation Solution

A cartridge and cartridge head assembly with a seal positioned upstream of the thread to isolate the fixing area from external agents, featuring a radial channel for filling without complete unscrewing, and a protective coating to prevent oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the cartridge head is regularly unscrewed and rescrewed for refilling operations, then refilling and metering operations can be performed, but the protective coating of the neck wears prematurely leading to oxidation of the metal

Engineering Contradiction:
Improverefilling operationVSAvoidprotective coating integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A seal is pre-installed in a groove on the cartridge neck, positioned upstream of the threads. This seal creates a protective barrier before any refilling operation begins, preventing external agents from reaching the metal surface during the entire screwing/unscrewing cycle

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The seal acts as an intermediary element between the external environment and the cartridge neck. It mediates the interaction by blocking the path of oxygen and chemical agents, allowing the cartridge head to be removed and reattached without compromising the protective coating

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the cartridge head is completely unscrewed for filling operations, then the cartridge can be filled, but the screwing and unscrewing operations cause mechanical wear and surface damage

Engineering Contradiction:
Improvefilling operationVSAvoidmechanical wear
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The seal is pre-positioned on the neck to establish protection before filling begins. The radial channel is also pre-formed to enable filling through a partial-screwed position, eliminating the need for complete unscrewing and reducing mechanical stress on the threads

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention replaces the traditional mechanical filling approach (complete unscrewing) with a modified system using a radial channel and seal. This allows filling to occur with the cartridge head partially attached, substituting the need for complete mechanical disassembly and thereby reducing wear

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

3Reliability

If the threads are exposed to external agents, then oxygen and chemical substances can cause oxidation and deterioration, but isolating the threads requires sealing mechanisms

Engineering Contradiction:
Improveoxidation resistanceVSAvoidsealing structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of sealing the entire cartridge assembly, the seal is applied locally only where needed - on the neck surface upstream of the threads. This localized sealing approach protects the critical threaded areas from oxidation while maintaining simplicity in the overall structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The seal functions as a thin film barrier that conforms to the neck surface. This flexible sealing approach effectively isolates the threads from external agents without requiring complex rigid sealing structures, maintaining device simplicity while ensuring protection

Inventive Principle:
Principle #30Flexible shells and thin films

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 prevents oxidation and mechanical damage, facilitating refilling operations while maintaining the integrity of the cartridge and ensuring effective sealing.

Implementation Method 1

a seal isolates the threads of the cartridge head and the cartridge from the outside of the cartridge head

Methodology Applied
Scientific EffectPhysical sealing: Physical Containment

Implementation Method 2

a radial channel is formed in the cap, the radial channel being configured to open onto the unthreaded end of the second part of the neck when the cartridge head is screwed onto the cartridge, a gap being further formed between the unthreaded end of the second part of the neck and the inside of the skirt so as to be able to fill, via the channel, the inside of the cartridge when the cartridge head is not completely screwed onto the cartridge

Methodology Applied
Scientific EffectPressure gradient flow: Pressure Gradient

Data Source

PatentEP4675152A1Cartridge and cartridge head assembly and apparatus therefor
Publication Date: 2026.01.07 ROTHGANGL
  • EP4675152A1 patent drawingFigure 1
  • EP4675152A1 patent drawingFigure 2~3
  • EP4675152A1 patent drawingFigure 4~5

AI summary

The present invention relates to a cartridge and cartridge head assembly (1), comprising a cartridge (2) having a neck (6) whose external surface comprises a first portion (8) of constant diameter extending into a second threaded portion (9), and a cartridge head (3) comprising a cap (12) from which a skirt (13) extends in one piece, the internal surface of the skirt (13) comprising a first portion (22) extending from the cap (12), of constant diameter, having a tapped hole configured to cooperate with the thread (9a) formed on the neck (6), and a second portion (23) of larger diameter than the first portion (22), one of the first portion (8) of the neck (6) and of the second portion (23) of the skirt (13) having a groove (25) in which a seal (26) is disposed, such that when the cartridge head (3) is fixed onto the cartridge (2),The seal (26) isolates the threads of the cartridge head (3) and the cartridge (2) from the outside of the cartridge head (3).