RTD Temperature Sensors

Temperature Sensors

Dwyer Instruments, Inc. offers a wide variety of temperature sensors that use RTDs as the sensing element.

RTDs are based on the principal that the electrical resistance of the wire is a function of the temperature, with the resistance increasing as temperature increases. The resistance varies nearly linearly with temperature per the Callendar Van-Dusen equation. The wire used in RTDs as the sensing element is usually constructed of platinum, copper, or nickel.  Platinum is the best material for this element, as it has the widest useful temperature range of these materials. It also has a very repeatable and linear temperature to resistance correlation. Continue reading “RTD Temperature Sensors”

U.S. and International Threaded Connection Standards

Threaded Connections

Threaded connections are often referred to as a process connection type. For Dwyer product specifications, this connection type is typically NPT (National Pipe Thread), which is an American standard thread. These connections allow products to be installed directly into piping or with the use of threaded fittings.

For threaded connections there are two common types, (1.) straight or parallel thread and (2.) tapered thread. Continue reading “U.S. and International Threaded Connection Standards”

Control Valve Sizing

Hi-Flow™ Valve Application

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 Hi-Flow™ Series, are a common type of control valve. In the example shown, a Hi-Flow™ control valve is controlling temperature by varying the amount of steam or cold water added to the process. Continue reading “Control Valve Sizing”