Control Valve Adjusts Gas-Air Mixture in Venturi Heaters

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Solution Overview

Problem

Heaters with pneumatic gas-air combinations lack the ability to adjust fuel gas mass flow during operation, especially under changing weather conditions or fuel gas quality, leading to inefficient combustion and operational instability.

Innovation Solution

Incorporating a control valve and control membrane system that adjusts the pressure between the Venturi device and final pressure to control the fuel gas mass flow, allowing for real-time adjustment of the mixture composition using a gas valve connected to the control membrane, enabling leaner or richer mixtures based on operational states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a venturi device is used to control fuel gas mass flow in a pneumatic gas-air combination, then the structure is simple and reliable, but the mixture composition cannot be adapted to changing fuel gas quality or weather conditions

Engineering Contradiction:

Improveadaptability to changing fuel gas quality and weather conditionsVSAvoidcomplexity of the heater structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A control membrane is introduced as an intermediary element between the venturi device and the gas valve. The control membrane receives the negative pressure signal from the venturi device and translates it into controlled opening of the gas valve, enabling adaptation to changing conditions while maintaining the simplicity of the pneumatic principle.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces part of the purely mechanical pneumatic system with an electropneumatic system by introducing an electrically controllable gas valve that responds to control signals from the control membrane, allowing electrical control of the fuel gas flow in response to sensor feedback about mixture composition.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If the control valve applies higher pressure to the control membrane, then less fuel gas is supplied for the same combustion air (leaner mixture), but the system becomes more complex

Engineering Contradiction:

Improveability to adjust mixture compositionVSAvoidcomplexity of control system

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The gas valve is made dynamically controllable through electrical actuation, allowing the opening position to be adjusted in real-time based on feedback from exhaust gas sensors or flame monitors. This enables continuous adaptation of the mixture composition during heater operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback control by using exhaust gas composition measurements or flame monitor data to adjust the gas valve opening position, thereby maintaining optimal mixture composition under varying operating conditions through a closed control loop.

Inventive Principle:

Principle #23Feedback

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 flexible control of the fuel gas mass flow, enhancing operational reliability and efficiency under varying conditions, ensuring safe and efficient combustion regardless of changes in fuel gas composition or weather factors.

Implementation Method 1

a venturi device (venturi nozzle) arranged in the combustion air supply, with a negative pressure arising in the venturi device determining the mass flow of the fuel gas

Methodology Applied

Scientific EffectVenturi effect: Venturi Effect

Implementation Method 2

the control valve is set up to apply a pressure in a range between a pressure in the Venturi device and a final pressure to the control membrane

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP4160093A1Method for operating a heating device, computer program, storage medium, control device, control device, heating device and use of a control valve

Publication Date: 2023.04.05 VAILLANT GMBH(DE)

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AI summary

A method for operating a heating device (1) is proposed, wherein the heating device (1) comprises a Venturi device (3), a gas valve (10), a control valve (8), and a regulating diaphragm (7), wherein: - a mass flow of fuel gas (11) is added to a mass flow of combustion air and controlled via the gas valve (10); - the gas valve (10) is operatively connected to the regulating diaphragm (7); - the control valve (8) is configured to pressurize the regulating diaphragm (7) with a pressure in a range between a pressure in the Venturi device (3) and an ultimate pressure. Thus, by controlled pressurization of the regulating diaphragm (7) with a pressure in a range between an ultimate pressure and the pressure of the Venturi device (3), the pneumatic gas-air mixture is enabled to influence the mixture composition during the operation of a heating device (1).