Adjustable Louver Damper for Flue Gas Mixing
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Solution Overview
Problem
Conventional gas mixers in boilers produce pressure drops at all boiler loads, requiring larger fans and increased auxiliary power consumption, and have longer transition sections that increase costs due to the need for high-temperature metals, while failing to efficiently mix gases under varying furnace loads.
Innovation Solution
A damper mixing device with adjustable louver design that minimizes pressure drop and optimizes mixing by regulating the angle of louvers to create turbulent mixing, allowing for efficient gas stream mixing in a shorter distance, reducing the need for separate mixers and high-temperature materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional mixers with angled, fixed vanes are used to mix gas streams, then the gases are mixed, but a pressure drop is produced at all boiler loads requiring larger, more expensive fans and increased auxiliary power consumption
Solution Approach 1:
The patent applies the dynamics principle by making the mixer vanes adjustable rather than fixed. The vanes can be positioned at different angles depending on the boiler load conditions, allowing the mixer to adapt to varying flow rates and maintain optimal mixing efficiency while minimizing pressure drop and power consumption at each operating point.
Solution Approach 2:
The patent changes the geometric parameter of the mixer vanes (angle of inclination) to optimize performance. By adjusting the vane angle parameter according to boiler load, the system achieves efficient mixing at different flow rates without incurring excessive pressure drops that would require larger fans and increased power consumption.
2Productivity
If conventional mixers are used to mix gases, then the gases are mixed, but a certain duct length (transition section) is required to sufficiently mix the flowing gas streams, resulting in excess high temperature gases contacting the flue duct surface causing hot spots
Solution Approach 1:
The adjustable vane design creates more effective turbulence and mixing action, achieving sufficient gas stream mixing in a shorter distance. This reduces the required transition section length and minimizes the exposure time for high-temperature gases to contact the flue duct surface, thereby reducing hot spot formation.
3Productivity
If conventional mixers with fixed vanes are used, then gas mixing is achieved, but the system requires high temperature metals to construct the device due to hot spots, which are more expensive than standard metal
Solution Approach 1:
By making the vanes adjustable, the system achieves more efficient mixing that reduces hot spot formation, allowing the use of standard metals instead of expensive high-temperature metals for constructing the mixer and flue duct components.
4Use of energy by moving object
If adjustable louver dampers are used to mix gas streams, then pressure drop is minimized and mixing is optimized, but the device complexity increases compared to conventional fixed vanes
Solution Approach 1:
The louver damper is designed to perform multiple functions: it controls flow rate, mixes gas streams, and can be adjusted to optimize performance for different boiler loads. This multi-functionality justifies the increased complexity by eliminating the need for separate flow control and mixing devices, ultimately reducing overall system complexity.
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 reduces system capital and operating costs by minimizing gas backpressure and power consumption, enabling faster gas mixing in a shorter transition area, and providing adjustable operation across the full boiler load range.
Implementation Method 1
regulating the angle of louvers to create turbulent mixing
Implementation Method 2
The economizer recovers heat from the flue gases to preheat feed water that is circulated back into the boiler
Data Source
Figure 1
Figure 2~4
AI summary
A gas mixing device has a plurality of interleaved rows of adjustable louvers. When at least two flowing gas streams are received that are desired to be mixed, the louvers of each row directs the gas streams in a direction different from that of the adjacent rows, mixing the gas streams. When effectively only a single flowing gas stream is received, the louvers are positioned vertically thereby reducing the pressure drop across the gas mixing device.