Picture this: You wake up with a start to the sound of crackling flames and the screech of an alarm. A nearby apartment room has caught fire, and you need to get out before it spreads to the rest of the building. You go through the motions; grab the keys, check the door knob, keep low to the ground. You head to the stairs and make your way outside to safety.
We often don’t think about the effects that relative humidity can have. It doesn’t stand out the way that the temperature of a room does, where a person might have to turn on a fan or turn up a heater. In fact, relative humidity is crucial to promoting good indoor air quality and is important to the health and safety of several different applications and areas.
Dwyer Instruments offers a multitude of sensors for monitoring air velocity in HVAC systems. Some of this instrumentation has a simple construction (Pitot tubes, for example) while others are more complex, such as hot-wire anemometers.
The initial term and first “hot-wire anemometer” was developed back in 1914 by Louie Vesso King. He is also accredited for King’s Law, which mathematically describes heat transfer in air flows using a heated wire. As the air moves over the wire, it causes a loss of temperature in the wire and removes some of the wire’s heat energy. Continue reading “The Basics of Air Velocity Sensors”
Have you ever wondered why there are a multitude of sensor output signals that can be configured on pressure, temperature, humidity, or gas sensing instrumentation used in process or HVAC applications? Most of these offerings were originally set up to allow sensor manufacturers to better align with the inputs offered by manufacturers of programmable logic controllers (PLCs) and direct digital controllers (DDCs), which are used for controlling processes for both automation and HVAC control.
I’d like to focus on two of the most commonly used output signals and zero in on the advantages and/ or disadvantages these output signals offer. Two of the most commonly used output signals include analog current, typically 4 to 20mA, and analog voltage, typically 0-10V. Continue reading “Understanding Sensor Output Signals”
Question: Is there a kit I can buy with the Magnehelic® Differential Pressure Gage for monitoring air filters, so that I don’t have to buy all the tubing, static pressure tips, and a bracket separately?