Downstream-Orifice Pressure Probe for Dust-Resistant Airflow Sensing
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Solution Overview
Problem
HVAC systems face inaccurate pressure readings due to dust accumulation and clogging of pressure probes in airflow ducts, which affects the monitoring and control of system conditions.
Innovation Solution
The design of pressure probes with pressure orifices axially aligned on a downstream side of an axial run, positioned laterally across airflow channels, reduces clogging and allows for accurate measurement of static pressure by orienting orifices in the downstream direction, eliminating the need for orifices on the upstream side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure probes are installed in airflow ducts to monitor system conditions, then system monitoring capability is improved, but the probes become susceptible to dust accumulation and clogging which degrades measurement accuracy
Solution Approach 1:
The pressure probe is segmented into multiple functional zones: a upstream side without orifices that acts as a dust shield, and a downstream side with axially aligned orifices that perform measurement. This segmentation allows the upstream portion to protect against dust accumulation while the downstream portion maintains measurement capability, resolving the contradiction between reliability and measurement precision.
Solution Approach 2:
The internal passage of the pressure probe serves as an intermediary element that channels airflow from the downstream orifices to the pressure sensor while being protected by the upstream section. This intermediary structure allows accurate pressure measurement without exposing the measurement orifices directly to dust-laden airflow, maintaining both reliability and precision.
2Measurement precision
If pressure orifices are positioned on both upstream and downstream sides of the axial run, then pressure measurement coverage is improved, but the upstream orifices become clogged with dust which degrades measurement reliability
Solution Approach 1:
The invention extracts the pressure orifices from the upstream side of the axial run, leaving only the downstream side with orifices. This extraction eliminates the problem of upstream orifice clogging while maintaining sufficient pressure measurement coverage through the downstream orifices and internal passage configuration, resolving the contradiction between measurement coverage and reliability.
Solution Approach 2:
Instead of placing orifices on the upstream side where they are exposed to dust, the invention inverts the approach by positioning all orifices on the downstream side where they are protected from direct dust exposure. This inversion maintains measurement capability while eliminating the clogging problem, resolving the contradiction between coverage and reliability.
3Reliability
If pressure orifices are axially aligned on the downstream side only, then clogging is minimized improving reliability, but measurement coverage may be reduced
Solution Approach 1:
The invention compensates for the reduced spatial distribution of orifices by utilizing the internal passage dimension to distribute pressure sampling along the axial run. The internally communicated pressure orifices sample pressure at multiple axial positions, providing comprehensive measurement coverage equivalent to having orifices on both sides, while maintaining the reliability benefits of downstream-only external orifices.
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 configuration enhances the accuracy of pressure measurements in HVAC systems by minimizing clogging and ensuring reliable differential static pressure data for monitoring unit conditions, improving the overall performance and efficiency of climate control systems.
Implementation Method 1
pressure orifices axially aligned along a downstream side of the axial run and in communication with the output end through the internal passage
Data Source
AI summary
A pressure probe includes a tube having an output end, an internal passage, an axial run, and pressure orifices axially aligned along a downstream side of the axial run. The pressure orifices are in communication with the output end through the internal passage and an upstream side of the axial run that is opposite from the downstream side of the axial run and does not include a pressure orifice. The downstream side is perpendicular to airflow.