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How Thermal Flowmeters Work

Thermal flowmeters use the thermal properties of the fluid to measure the flow of a fluid flowing in a pipe or duct. In a typical thermal flowmeter, a measured amount of heat is applied to the heater of the sensor. Some of this heat is lost to the flowing fluid. As flow increases, more heat is lost. The amount of heat lost is sensed using temperature measurement(s) in the sensor. The transmitter uses the heat input and temperature measurements to determine fluid flow. Most thermal flowmeters are used to measure gas flows. Thermal flowmeters represent 2% of global flowmeter sales. Continue reading “How Thermal Flowmeters Work”

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Mitigating Methane in Landfills

landfill degassing

landfill degassingIn the ongoing narrative of environmental conservation, few adversaries are as concerning as methane gas emissions from landfills. This potent greenhouse gas poses a substantial threat to both our climate and community health, demanding immediate attention and sustainable solutions. 

Landfills contain several different gases and volatile organic compounds (VOCs) caused by the breakdown of waste, with methane and carbon dioxide making up over 90% of them (health.ny.gov). Once waste breaks down and forms landfill gas and particulates, it can potentially spread to nearby buildings or structures through openings like cracks, windows, or ventilation systems and settle in areas of poor ventilation like basements or crawl spaces (health.ny.gov).   Continue reading “Mitigating Methane in Landfills”

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Navigating Health and Comfort in Airports

In the expansive world of modern travel, airports serve as dynamic hubs connecting people across the globe. However, amid the seamless connectivity and operational efficiency, there exists a nuanced concern—the potential health implications associated with prolonged stays in these bustling environments. From temporary discomforts to potential long-term health risks, both passengers and airport employees may encounter various challenges unique to airport spaces.  

Although the COVID-19 pandemic brought concerns about the impact of the built environment on health out of the proverbial “back room,” experts have been mulling over solutions to these problems for decades. Airports are of particularly high concern as they act as something of a mini city. Jet fuel, exhaust, and other chemicals have a large environmental impact on the outdoor air quality, while carbon dioxide and volatile organic compounds (VOCs), like formaldehyde, can greatly impact the health and indoor air quality (IAQ) of airport occupants.  Continue reading “Navigating Health and Comfort in Airports”

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Flow Measurement with Orifice Plates

Dwyer Instruments offers many types of flow measuring products including orifice plates, which are used as a flow sensing element with a differential pressure monitor.

Orifice Plates

Orifice plates are a primary flow element, detecting the flow of a fluid passing through the plate by sensing the pressure drop across the plate. When a fluid flows through a restriction in a pipe, it creates a pressure difference between upstream and downstream of the restriction. This pressure difference is proportional to flow rate according to Bernoulli’s principal, similar to a Pitot tube.  Orifice plates are commonly used as they are simple to use, low cost, work with gases or liquids, and require low maintenance.  Adversely, they do have large pressure losses with about 50% of the pressure drop not recoverable.  Continue reading “Flow Measurement with Orifice Plates”

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How Electromagnetic Flowmeters Work

Electromagnetic flowmeters, also known as magnetic flowmeters or magmeters, use Faraday’s Law of Electromagnetic Induction to determine the flow of liquid in a pipe. In an electromagnetic flowmeter, a magnetic field is generated and channeled into the liquid flowing through the pipe. Following Faraday’s Law, flow of a conductive liquid through the magnetic field will cause a voltage signal to be sensed by electrodes located on the flow tube walls. When the fluid moves faster, more voltage is generated. Faraday’s Law states that the voltage generated is proportional to the movement of the flowing liquid. The electronic transmitter processes the voltage signal to determine liquid flow.

In contrast with many other flowmeter technologies, electromagnetic flowmeter technology produces signals that are linear with flow. As such, the turndown associated with magnetic flowmeters can approach 20:1 or better without sacrificing accuracy. Continue reading “How Electromagnetic Flowmeters Work”