Multi-Stage Orifice Damper for Wide-Range HVAC Flow Measurement
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Solution Overview
Problem
Current fluid flow measurement devices are expensive and have limited turndown ratios, making them ineffective for accurately measuring low fluid flows, leading to inefficient energy consumption and operational challenges in HVAC systems.
Innovation Solution
A fluid flow measurement and control system using a multi-stage damper with a variable orifice plate and actuator assembly, coupled with a controller that determines flow rates based on pressure differentials and magnification coefficients, enabling precise measurement and control of fluid flows across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow measurement devices are used, then measurement capability is provided, but cost is high and turndown ratio is limited
Solution Approach 1:
The patent replaces conventional mechanical flow measurement devices with a magnetic field-based measurement system. The system uses a magnetic sensor to detect the position of a magnetic element on the orifice plate, substituting mechanical linkages and moving parts with magnetic field interactions. This reduces device complexity and cost while maintaining measurement precision.
Solution Approach 2:
The patent introduces a magnetic element as an intermediary between the orifice plate position and the magnetic sensor. This magnetic intermediary enables non-contact measurement of the orifice opening area, allowing accurate flow measurement without complex mechanical coupling or direct physical contact between measurement components.
2Adaptability or versatility
If conventional flow measurement devices are used, then measurement capability is provided, but turndown ratio is limited to less than 10:1
Solution Approach 1:
The patent implements a dynamically adjustable orifice plate system where the opening area can be continuously varied from nearly closed to fully open positions. The magnetic sensor tracks the orifice plate position throughout the entire range of motion, enabling accurate measurement across a wide turndown ratio exceeding 100:1, unlike conventional fixed-orifice devices.
Solution Approach 2:
The system changes the opening area parameter of the orifice plate dynamically to accommodate varying flow requirements. By combining variable orifice area with magnetic position sensing, the system maintains measurement accuracy across different flow conditions while achieving high adaptability through turndown ratios greater than 100:1.
3Use of energy by moving object
If HVAC systems operate without accurate flow measurement, then system simplicity is maintained, but energy consumption increases due to inability to modulate flow
Solution Approach 1:
The patent implements a feedback control system where the magnetic sensor continuously monitors the orifice plate position and provides data to a controller. The controller adjusts the actuator to maintain the desired flow rate, enabling energy-efficient modulation of HVAC systems. This feedback mechanism allows precise flow control while managing system complexity through integrated electronic control.
4Adaptability or versatility
If multi-stage damper with variable orifice plate is implemented, then turndown ratio is increased to greater than 100:1, but device structural complexity increases
Solution Approach 1:
The patent employs a nested damper structure where an inner damper is positioned within an outer damper assembly. This nested configuration allows both dampers to operate independently or in combination, achieving high turndown ratios through staged flow restriction. The nested design compactly integrates multiple control stages without proportionally increasing overall device complexity.
Solution Approach 2:
The damper system is segmented into multiple independent stages (inner damper and outer damper) that can be controlled separately. This segmentation allows each stage to handle specific portions of the flow range, collectively achieving turndown ratios greater than 100:1 while keeping each individual damper component relatively simple in structure.
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 system provides high turndown ratios, reducing energy consumption, improving accuracy, and streamlining product portfolios by enabling precise measurement and control of fluid flows, thus enhancing HVAC system efficiency and compliance with energy standards.
Implementation Method 1
a first sensor disposed upstream of, and a second sensor disposed downstream of, the orifice plate... determine a pressure differential based on a first pressure obtained by the first sensor and second by the second
Implementation Method 2
A multi-stage damper can be used to address limitations of a standard butterfly damper... the vena contracta of the inner disk can be controlled, not by the area projected normal to the duct as in the standard butterfly damper, but by the projection of the inner annulus opening A0 normal to the faces of the annulus and opening disk itself
Data Source
AI summary
Systems and methods for measuring and controlling fluid flow comprises an orifice plate defining a variable opening, wherein the orifice plate includes an outer assembly comprising a central opening and an inner assembly extending through the central opening. Another embodiment comprises a plurality of blades disposed parallel to each other, wherein the blades are pivotable along its longitudinal axis and include at least one low-flow blade or partial blade and a plurality of high-flow blades The flow device regulates high and very low volumes of fluid with precision, inexpensively, with superior acoustics, reduced energy, a simpler design, and prevents building infiltration. The high turndown device permits use at lower velocities, thereby reducing noise generation and eliminating need for sound-attenuating liners. The high rangeability device combines several part numbers into fewer parts, thereby streamlining product portfolios. Cost benefits associated with the flow device allow equipment to be scaled back 100:1 rather than legacy 4:1, providing energy savings, fewer product variations, simple and more robust applications. The device meets new and old building fresh air, comfort and energy codes. The flow device can be engineered, selected, and sized without sophisticated software programs.