Variable Orifice Gas Flow Modulating Valve Design
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Solution Overview
Problem
Traditional gas valves for appliances suffer from output fluctuations and undesirable combustion issues due to modulating gas flow, leading to inefficient heat control and flame quality.
Innovation Solution
A variable orifice gas flow modulating valve is designed with an orifice hood, a metering pin, and an actuator that moves the pin or hood to control gas flow, featuring a tapered section and fins to maintain a constant pressure and velocity, ensuring complete combustion and stable temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas flow is modulated in variable gas valves, then output control with less fluctuations is achieved, but gas-air mixture quality deteriorates causing undesirable combustion
Solution Approach 1:
The gas flow path is segmented into multiple independent channels, each with its own metering orifice. This allows separate control of gas flow rate and gas-air mixture composition, enabling modulation of output while maintaining proper combustion conditions through dedicated mixture adjustment mechanisms
Solution Approach 2:
A mixing chamber is introduced as an intermediary component between the gas flow modulation mechanism and the burner. This mixing chamber ensures proper gas-air mixture formation regardless of flow rate variations, acting as a buffer that decouples flow modulation from mixture quality degradation
2Device complexity
If traditional on/off valves are used, then simple two-position control is achieved, but appliance output fluctuates undesirably
Solution Approach 1:
The valve transitions from static on/off positions to dynamic multi-position capability through movable metering pins with variable orifice openings. This allows continuous adjustment of gas flow rate to match heating demands, providing stable appliance output through proportional control rather than binary switching
Solution Approach 2:
The valve controls multiple parameters simultaneously including flow rate, orifice opening size, and gas pressure. By varying these parameters continuously rather than switching between fixed states, the system achieves stable appliance output while maintaining simple valve structure through a single actuating mechanism
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 stable temperature control in gas appliances by maintaining a constant gas flow, preventing fluctuations and ensuring a 'hard blue' flame, which results in efficient combustion and reduced emissions.
Implementation Method 1
The recess includes a tapered section that narrows from a wide portion to a narrow portion... to maintain a constant pressure and velocity
Implementation Method 2
ensuring complete combustion and stable temperature control... results in efficient combustion
Data Source
AI summary
A temperature control system for a gas appliance utilizes an improved variable orifice gas flow modulating valve (10) capable of direct modulation of gas flow through an orifice (20) directly into a gas burner (54) to provide a constantly maintained temperature in an appliance working compartment, as selected by human interface via a temperature selector. An actuator (12) attached to a gas fitting body (14) of the valve provides for linear movement of a metering pin (16) into the taper inside the orifice, accomplishing the variable controlled modulated flow of gas directly into the burner. The actuator (12) is controlled by an input signal from a programmable controller (90) whose output is determined by calculations based on inputs from a temperature selector and a temperature sensor located in the gas appliance working compartment.