Control Valve Actuator Sizing and Valve Action Selection

Control valves are used to change process conditions such as flow, temperature, level, and pH. A complete control system would include: a sensor, controller, positioner or current to pressure transducer, and control valve.  Globe valves, such as the Dwyer Series 2000VA/ 3000WA Hi-Flow™ Control Valve, are a very common type of control valve.

Hi-Flow™ Valve

The Dwyer Hi-Flow™ Series control valves have pneumatic actuators that modulate the valve for flow control. The opening, closing and throttling of the valve plug is accomplished by varying the air pressure to the diaphragm in the actuator. Typically the control pressure signal is 3 to 15 psig. There are two types of actuators: Air-To-Lower and Air-To- Raise. Continue reading “Control Valve Actuator Sizing and Valve Action Selection”

An Introduction to Lead-Free Product Requirements

In a world of constantly changing approvals and requirements, is it realistic to expect a customer to stay up-to-date with the latest and greatest information? Things that were once deemed acceptable are now found to cause serious health complications. Consequentially, there are all kinds of agencies in place designed to keep products safe, regulate material composition, and educate the consumer.

But how does an individual, not experienced in the industry, know what is necessary (or pertinent) to their specific application? If I want to purchase a water meter for my home or business and am unfamiliar and unlicensed with those specific regulations, am I putting myself or my business at risk? Particularly something like lead, which according to the CDC ,“[…] can affect nearly every system in the body.” Continue reading “An Introduction to Lead-Free Product Requirements”

Air Balancing HVAC Systems

Methods of Air Balancing

Air balancing a distribution system is needed to properly direct the air flow in order to optimize the system’s design. Flow rates are tested, adjusted, and balanced as cubic feet per minute (CFM) or cubic meters per hour (m3/h). There are two traditional methods for balancing airflow at the terminals. The first is sequential balancing, which involves setting the zone and branch dampers in sequence. However, the most common method of air balancing is called proportional balancing.

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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”