Non-Dispersive Infrared, NDIR, Carbon Dioxide Sensors

Non-Dispersive Infrared, NDIR, CO2 Sensors

Dwyer offers several carbon dioxide measuring products that use non-dispersive infrared sensors as the sensing element. Carbon dioxide sensors are commonly used in building automation systems to monitor air quality.  The level of carbon dioxide is indirectly proportional to the amount of people in a space and can be used to adjust ventilation for the space.


There are two basic types of gas sensing technologies: chemical reaction and infrared spectroscopic. Most chemical reaction sensors are electrochemical sensors, which are not as reliable as they can interact with multiple gases and wear from interaction with the gas. Continue reading “Non-Dispersive Infrared, NDIR, Carbon Dioxide Sensors”

The Operation of Gages and Switches in Hazardous Environments

In many industrial processes, the materials and the end product or by-products of the process, such as dust or vapors, can create conditions for a hazardous environment. Processes that have potential for hazardous environments include: water treatment, oil drilling, gas and chemical processing, power generation, pharmaceutical, and food manufacturing. The measurement and control of these processes are essential in maintaining optimal conditions of the manufacturing system and preventing catastrophic events.  Continue reading “The Operation of Gages and Switches in Hazardous Environments”

The Making of a Market Leader – The Magnehelic® Differential Pressure Gage

The name of the Magnehelic® Differential Pressure Gage was derived from the terms Magnet and the Helix. The Magnehelic® Gage is a simple yet elegant solution, which solved a problem faced by customers who wanted to measure low differential pressure. Historically the industry measured differential
Molded Plastic Manometers Series Mark II

pressure with a liquid filled manometer. The manometer worked on the principle that the difference in air pressure is measured as a function of gravity and liquid density. The challenge, however, was that the liquid in the manometer evaporates over time. This means that individuals would need to regularly add more liquid and re-calibrate the device. Continue reading “The Making of a Market Leader – The Magnehelic® Differential Pressure Gage”

Balancing a HVAC System with Multiple Diffuser Types

The Problem

  • Standard air flow hoods do not correct for diffuser type when balancing a system.
  • Proportional balancing is extremely difficult when a mixture of diffusers are present, due to the inaccuracy of standard hoods on slot diffusers.
  • Below is a sample of diffusers tested on Dwyer’s Precision Air Calibration Station (Figure A) with a standard air flow hood followed by the Dwyer SMART Air Hood™ Balancing Instrument (Series SAH).

Figure A: Precision Air Hood Calibration Station
Continue reading “Balancing a HVAC System with Multiple Diffuser Types”