Functions of Pressure Detectors
Pressure Detector Functions Although the pressures that are monitored vary slightly depending on the details of facility design, all pressure detectors are used to provide up to three basic functions:…
Functions of Temperature Detectors
Functions of Temperature Detectors Although the temperatures that are monitored vary slightly depending on the details of facility design, temperature detectors are used to provide three basic functions: indication, alarm,…
Resistance Type Pressure Transducers Principle
Resistance-Type Pressure Transducers Included in this category of transducers are strain gauges and moving contacts (slidewire variable resistors). Figure 1 illustrates a simple strain gauge. A strain gauge measures the…
Inductance Type Pressure Transducers Principle
The inductance-type transducer consists of three parts: a coil, a movable magnetic core, and a pressure sensing element. The element is attached to the core, and, as pressure varies, the…
Capacitive Type Pressure Transducers Principle
Capacitive-type transducers, illustrated in Figure, consist of two flexible conductive plates and a dielectric. In this case, the dielectric is the fluid. As pressure increases, the flexible conductive plates will…
Bridge Circuit Construction
Figure 1 shows a basic bridge circuit which consists of three known resistances, R1, R2, and R3 (variable), an unknown variable resistor RX (RTD), a source of voltage, and a…
Thermocouple Construction
A thermocouple is constructed of two dissimilar metal wires joined at one end. When one end of each wire is connected to a measuring instrument, the thermocouple becomes a sensitive…
Resistance Temperature Detectors (RTD) Construction
The RTD incorporates pure metals or certain alloys that increase in resistance as temperature increases and, conversely, decrease in resistance as temperature decreases. RTDs act somewhat like an electrical transducer,…
Applications of Needle Valves
A needle valve is a type of valve having a small port and a threaded, needle-shaped plunger. It allows precise regulation of flow, although it is generally only capable of relatively low flow rates. Applications of Needle Valves…
Blowout preventer (BOP) Principle
A blowout preventer (BOP) is a large, specialized valve or similar mechanical device, used to seal, control and monitor oil and gas wells to prevent blowouts, the uncontrolled release of crude oil and/or natural gas from a…
