Interchangeable Gas Restrictor for Hydrogen and Hydrocarbon Adaptability

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Solution Overview

Problem

Existing air-gas mixture burning appliances require exchange of parts such as gas restrictors and gas valves when switching between different gases, which is inconvenient and costly, and poses safety risks due to differences in flame speed and burner temperature.

Innovation Solution

The development of interchangeable gas restrictors with different Reynolds numbers, allowing for the creation of either turbulent or laminar gas flows, enabling the appliance to operate efficiently with both hydrocarbon gases and hydrogen without the need for part exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If gas restrictor and gas valve are exchanged when switching between different gases, then the appliance can operate with different gas types, but the device complexity and operation difficulty increase

Engineering Contradiction:

Improvegas type adaptabilityVSAvoidpart exchange requirement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The gas restrictor is designed with a universal structure that can accommodate different gas types (hydrocarbon gases and hydrogen) without requiring physical exchange. The single gas restrictor design integrates multiple flow control capabilities through adjustable parameters rather than requiring multiple fixed restrictors for different gases.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of changing the physical gas restrictor component, the system changes operational parameters (gas valve opening degree, air-gas ratio) to adapt to different gas types. The gas restrictor maintains fixed geometric parameters while the control system adjusts flow rates and mixing ratios to optimize performance for each gas type.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If gas restrictor and gas valve are exchanged when switching between different gases, then the appliance can operate with different gas types, but the loss of time and productivity decrease

Engineering Contradiction:

Improvegas type adaptabilityVSAvoidconversion time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control system pre-stores optimal operating parameters (gas valve opening degrees, air-gas ratios) for different gas types. When switching gas types, the system automatically retrieves and applies the pre-calculated parameters, eliminating the need for manual adjustment and reducing conversion time to minimal gas valve actuation time.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If conventional gas restrictor design is used, then the structure is simple, but the safety and reliability decrease due to flame flashback risk

Engineering Contradiction:

Improvegas restrictor structureVSAvoidflame flashback prevention

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system dynamically adjusts the air-gas ratio parameter based on the type of gas being used. For hydrogen, which has higher flame speed and lower ignition energy requirements, the system increases the air-gas ratio to create a leaner mixture that is less prone to flashback. For hydrocarbon gases, the system uses optimal stoichiometric or slightly lean ratios. This parameter adjustment maintains safety without requiring complex structural modifications to the gas restrictor.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The control system incorporates feedback from gas type identification to automatically adjust operating parameters. The gas type detection triggers the control system to select appropriate air-gas ratios and valve opening degrees, creating a closed-loop safety mechanism that adapts to different gas properties and prevents flashback conditions without requiring complex mechanical safety devices.

Inventive Principle:

Principle #23Feedback

4Ease of manufacture

If conventional gas restrictor design is used, then the manufacturing is simple, but the thermal efficiency and operability worsen

Engineering Contradiction:

Improvegas restrictor manufacturingVSAvoidthermal efficiency

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The system maintains the simple geometric structure of the gas restrictor for ease of manufacture, but compensates for thermal efficiency requirements through dynamic parameter adjustment. The control system modifies gas flow rate, air-gas ratio, and valve opening degree based on gas type and operating conditions, achieving optimal combustion efficiency without requiring complex restrictor geometries or multiple specialized components.

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

This solution allows for safe and efficient operation of air-gas mixture burning appliances on different gases, maintaining thermal efficiency and reducing the risk of flame flashback by adjusting the air-gas ratio based on the gas type.

Implementation Method 1

a gas restrictor that restricts flow of gas from the gas valve to the point of mixing

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Implementation Method 2

The gas restrictor has usually a cross sectional area which is smaller than elsewhere in the gas channel between the gas valve and the Venturi-type mixing nozzle

Methodology Applied

Scientific EffectFlow restriction through reduced cross-sectional area:

Implementation Method 3

The Venturi-type mixing nozzle usually comprises an air way with a converging channel in order to accelerate the air stream for creating a decreased air pressure. This decreased air pressure, which may also be referred to as suction pressure, causes a suction effect on the gas stream

Methodology Applied

Scientific EffectVenturi effect: Venturi Effect

Implementation Method 4

a gas governor that is adapted to control supply of gas to the point of mixing via the gas channel, wherein the gas governor comprises a gas valve that is adapted to control gas pressure in the gas channel dependant on an air pressure signal

Methodology Applied

Scientific EffectPressure regulation:

Data Source

PatentEP4191135B1An air-gas mixing unit for an air-gas mixture burning appliance

Publication Date: 2025.05.07 BOSCH THERMOTECHNOLOGY LTD (UK)

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AI summary

In an air-gas mixing unit for an air-gas mixture burning appliance, comprising: at least one air-gas mixer (118), an air supply (112) with an airway (212), and a gas supply (116) with a gas channel (216) that is connected to a gas governor (210), wherein the gas governor comprises: a gas valve (215) that is adapted to control gas pressure in the gas channel (216) dependant on an air pressure signal (235) that is indicative of a static air pressure in the air way, and a gas restrictor (250) that restricts flow of gas from the gas valve to a point of mixing (119); the gas restrictor is interchangeable between at least one first gas restrictor that is embodied to form a gas flow with a first Reynolds number and at least one second gas restrictor that is embodied to form a gas flow with a second Reynolds number.