Bidirectional Pressure Sensor Flow Direction Detection for VAV Installation

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Solution Overview

Problem

Bidirectional pressure sensors in VAV controllers can lead to confusion and incorrect installations of airflow hoses, resulting in increased costs and downtime due to the need for manual verification of airflow direction.

Innovation Solution

A computerized method using a processing circuit to receive pressure information from a bidirectional pressure sensor, evaluate it over time, and determine the airflow direction by comparing current pressures to past pressures, eliminating the need for manual verification by assigning a flow direction based on dynamic thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a bidirectional pressure sensor is used to measure airflow in both directions, then the measurement capability is improved, but installation confusion and errors increase due to technicians not knowing which side to connect hoses

Engineering Contradiction:

Improvemeasurement capabilityVSAvoidinstallation ease

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system automatically determines airflow direction by monitoring pressure differential signs without requiring technician intervention or manual verification. The processor circuit autonomously evaluates pressure signals, detects flow direction changes, and adjusts measurements accordingly, eliminating the need for technicians to manually verify hose connections or understand sensor orientation.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system changes the interpretation of pressure sensor readings based on detected flow direction. By monitoring the sign of the pressure differential over time and detecting when it transitions from positive to negative (or vice versa), the system dynamically adjusts which pressure reading corresponds to inlet versus outlet, allowing the same bidirectional sensor to accurately measure both flow directions without reconfiguration.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If manual verification of hose installation is performed to ensure correct airflow direction, then installation accuracy is improved, but installation time and downtime increase

Engineering Contradiction:

Improveinstallation accuracyVSAvoidinstallation time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The system continuously monitors pressure differential signals and provides real-time feedback about airflow direction. By evaluating the sign of the pressure reading over time and detecting transitions, the system automatically verifies correct installation and identifies flow direction changes, eliminating the need for manual verification while maintaining high installation accuracy.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces manual mechanical verification procedures with an automated electronic detection system. The processor circuit electronically monitors pressure signals, detects flow direction through signal analysis, and automatically adjusts measurements, substituting the mechanical/manual process of hose verification with an automated sensor-based system that reduces both time and potential for human error.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If differently colored tubes are used to designate installation sides, then installation confusion is reduced, but device complexity and cost increase

Engineering Contradiction:

Improveinstallation easeVSAvoiddevice complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The bidirectional pressure sensor system performs self-identification of flow direction through automatic detection of pressure differential signs. Rather than requiring external differentiation mechanisms like colored tubes, the sensor autonomously determines which direction airflow is moving by monitoring pressure sign changes, making the system self-configuring and eliminating the need for additional identification components.

Inventive Principle:

Principle #25Self-service

4Manufacturing precision

If technicians are required to know the correct installation orientation, then installation accuracy is improved, but the skill requirement and training needs increase

Engineering Contradiction:

Improveinstallation accuracyVSAvoidskill requirement

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The system performs self-configuration by automatically detecting airflow direction through pressure differential monitoring. The processor circuit evaluates pressure signals, detects when the sign transitions from positive to negative (indicating flow direction change), and automatically adjusts measurements accordingly. This eliminates the need for technicians to understand sensor orientation or installation orientation requirements, making the system accessible to technicians with minimal training while maintaining high installation accuracy.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9528865B2Methods and systems for determining flow direction using a bidirectional pressure sensor

Publication Date: 2016.12.27 JOHNSON CONTROLS TECHNOLOGY CO

AI summary

Computerized methods and systems for determining flow direction relative to a bidirectional pressure sensor are provided. The method includes receiving pressure information from the bidirectional pressure sensor. The method includes using the pressure information to evaluate, at a processing circuit, pressure at the bidirectional pressure sensor over time, The method includes assigning a flow direction to a current pressure of the bidirectional pressure sensor by comparing the current pressure to at least one past pressure.