Venturi Mixer Nozzle Segmentation for Gas Burner Modulation
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Solution Overview
Problem
Existing gas burner mixing devices have limited modulation range and quality due to the interaction with fans, allowing only a reduction to 20% of full-load speed while maintaining a desired gas-to-combustion air ratio, restricting their operational flexibility.
Innovation Solution
The mixing device incorporates multiple annular-gap-like nozzle sections within the Venturi device, each with a smaller diameter than the traditional single nozzle, allowing for a larger modulation range and maintaining a high modulation quality by reducing fan speed to 10% of full-load speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single annular-gap nozzle is used in the Venturi device, then the device structure is simple, but the modulation range is limited to 1-5 with fan speed reduction only to 20% of full-load speed
Solution Approach 1:
The single annular-gap nozzle is segmented into multiple annular-gap nozzles arranged in parallel within the Venturi device. Each nozzle has a smaller cross-section than the original single nozzle, and their combined cross-sectional area equals that of the original nozzle. This segmentation enables the mixing device to achieve a wider modulation range of 1-10 by allowing fan speeds to be reduced to 10% of full-load speed while maintaining proper gas-to-combustion air ratio.
2Use of energy by moving object
If fan speed is reduced to maintain lower gas flow, then energy consumption decreases, but the gas-to-combustion air ratio becomes inaccurate with single nozzle design
Solution Approach 1:
The segmented nozzle structure with multiple parallel annular-gap nozzles maintains stable flow distribution characteristics across a wider range of fan speeds. This allows the system to reduce fan speed to 10% of full-load speed for energy savings while preserving accurate gas-to-combustion air ratio control, extending the feasible modulation range to 1-10.
3Area of stationary object
If a single large-diameter nozzle is used, then the mixing section cross-section is large, but the modulation quality deteriorates at low fan speeds
Solution Approach 1:
The large-diameter single nozzle is replaced by multiple smaller-diameter nozzles arranged in parallel, where the sum of their cross-sectional areas equals the original large nozzle area. This segmentation maintains adequate mixing section cross-section for proper flow distribution while improving modulation quality at low fan speeds, enabling reliable operation down to 10% of full-load speed.
Solution Approach 2:
Each individual nozzle in the parallel arrangement has optimized local dimensions and flow characteristics suited for stable operation at reduced speeds. The distributed arrangement of multiple nozzles creates more uniform local flow patterns compared to a single large nozzle, improving overall mixing quality across the entire modulation range.
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 design enables a wider modulation range from 1 to 10 with improved modulation quality, ensuring efficient gas-to-combustion air mixing across varying fan speeds while maintaining a compact design.
Implementation Method 1
The Venturi device, positioned within the housing, is designed as a Venturi nozzle and serves to mix the combustion air and the gas
Implementation Method 2
the combustion air can be supplied to the mixing section via the contraction section which narrows towards the mixing section
Implementation Method 3
the mixture of gas and combustion air can be supplied to the outlet via the widening diffuser section
Data Source
Figure 1
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AI summary
The device (10) has a housing (11) with a combustion air inlet (13), a gas inlet (14) and an outlet (15) for a mixture of gas and combustion air. A venturi-device (12) is outlined under formation of a contraction section (19), a mixing section (20) and a diffuser section (21). The mixing section comprises multiple nozzle sections (22), which forms partial mixing sections (23) by which combustion air is mixed with the gas. The partial mixing sections have a smaller diameter or cross section than the mixing section. An independent claim is also included for a gas control device for a gas burner.