Dwyer Instruments offers many electrical switch products that make or break a contact based on sensing a parameter such as pressure, temperature, level, and so on.
Most switches are single pole double throw, often referred to as SPDT. This type of switch has one normally open contact and one normally closed contact. Switches can also be double pole double throw, or DPDT, that have two normally open and two normally closed contacts. Single pole single throw switches with just one contact are also available and are specified to be either normally open or normally closed.
Continue reading “What is Deadband? Switch Actuation and Deactuation”
The velocity of an air stream in a duct is not uniform over the cross section of the duct. This is because friction against duct walls causes the air velocity to be lower near the sides than the velocity in the center, creating a parabolic velocity profile. 
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.