Bi-Directional Draft Controller for Chimney Systems
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Solution Overview
Problem
Existing chimney systems require complex and costly PID loop controllers and hardware for draft management, which occupy significant space and incur high initial, operational, and maintenance costs.
Innovation Solution
A reversible draft controller system using an axial fan blade and an electronically commutated motor, controlled by a processor with a program to adjust draft by rotating the fan blade in opposite directions to manage both excessive and insufficient draft pressures, eliminating the need for a separate damper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate draft inducer and over-draft damper are used to control chimney draft pressures, then draft control capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the draft inducer and over-draft damper into a single bi-directional fan unit. The fan can rotate in a first direction to induce draft when pressure is positive, and rotate in a second direction to act as an over-draft damper when pressure is negative, thereby eliminating the need for separate components and reducing system complexity while maintaining full draft control capability
Solution Approach 2:
The bi-directional fan serves multiple functions: it acts as a draft inducer when rotating in the first direction and as an over-draft damper when rotating in the second direction. This multi-functionality allows a single component to replace what were previously two separate components, reducing device complexity while preserving comprehensive draft control
2Reliability
If separate draft inducer and over-draft damper hardware are installed, then draft management capability is improved, but space requirements increase
Solution Approach 1:
The patent merges the draft inducer and over-draft damper into a single integrated bi-directional fan assembly, thereby reducing the physical space required while maintaining both draft induction and over-draft prevention capabilities through the fan's ability to rotate in opposite directions
3Measurement precision
If multiple PID loops and control hardware are implemented, then draft control precision is improved, but operational and maintenance costs increase
Solution Approach 1:
The patent consolidates multiple PID control loops into a single unified control system that manages the bi-directional fan. This reduces the number of controllers, sensors, and associated hardware needed, thereby lowering operational and maintenance costs while maintaining precise draft control through the fan's bi-directional operation
Solution Approach 2:
The single controller manages both draft induction and over-draft prevention functions through the multi-functional bi-directional fan, eliminating the need for separate control systems and reducing operational complexity and costs while preserving precise control capability
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 reduces system complexity and costs while maintaining draft pressures within precise bi-directional tolerance (+/−0.25″ WC), optimizing space usage and operational efficiency.
Implementation Method 1
an electronically commutated motor (ECM), and a controller. The ECM is configured to rotate the axial fan blade in a first direction to increase the draft in the chimney and to rotate the axial fan blade in a second direction (opposite to the first direction) to decrease the draft in the chimney
Data Source
AI summary
Reversible draft controllers and exhaust systems incorporating reversible draft controllers are disclosed. One system for controlling draft in a chimney includes a sensor for determining condition data, an axial fan blade, an electronically commutated motor (ECM), and a controller. The ECM is configured to rotate the fan blade in a first direction to increase draft in the chimney and in a second, opposite direction to decrease draft. The controller has a processor and a program of instructions executable by the processor to perform steps for controlling draft in the chimney with the fan blade. The steps include: comparing condition data from the sensor to set point data to determine if an intervention is required; addressing insufficient draft by actuating the ECM to rotate the axial fan blade in the first direction; and addressing excessive draft by actuating the ECM to rotate the fan blade in the second direction.