A sliding-stem valve body is one where the moving parts slide with a linear motion. Some examples of…
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An on/off valve is the fluid equivalent of an electrical switch: a device that either allows unimpeded flow or…
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The following collection of photographs chronicles the complete disassembly of a Fisher E-body globe valve…
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When a high-energy photon strikes an atom, it may eject one of the lower-level electrons from its shell,…
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In some process applications, it is important that the control valve be able to completely stop fluid flow…
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The Law of Continuity for fluids states that the product of mass density (\(\rho\)), cross-sectional pipe area…
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The purpose of a control valve actuator is to provide the motive force to operate a valve mechanism. Both…
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A sliding-stem valve body is one where the moving parts slide with a linear motion. Some examples of…
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Displacer level instruments exploit Archimedes’ Principle to detect liquid level by continuously…
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An important design parameter of a control valve is the position it will “fail” to if it loses…
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Control valves are supposed to deliver reliable, repeatable control of process fluid flow rate over a wide…
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There are many process control applications in the industry where it is desirable to have multiple control…
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Current is the name we give to the motion of electric charges from a point of high potential to a point of low…
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Another category of control strategies involves the use of signal relays or function blocks with the ability…
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This section shows some of the many instrument symbols found in different types of technical diagrams used to…
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Fluid pressure exerts force on any surface area it contacts, as described by the formula \(F = PA\). One…
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So far we have just looked at instruments that sense, control, and influence process variables. Transmitters,…
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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…
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Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
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The disadvantages of pneumatic instruments are painfully evident to anyone familiar with both pneumatic and…
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Valve actuators provide force to move control valve trim. For precise positioning of a control valve, there…
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Some analyzers measure the composition of a process stream by directly immersing the sensing element in that…
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Self-balancing pneumatic instrument mechanisms are very similar to negative-feedback operational amplifier…
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Control strategies such as cascade, ratio, feedforward, and those containing limit and selector functions can…
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Current is the name we give to the motion of electric charges from a point of high potential to a point of low…
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“Feedforward” is a rather under-used control strategy capable of managing a great many types of…
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As a general rule, high achievement only takes place in an atmosphere of high expectations. Sometimes these…
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Many traditional flowmeter technologies respond to the volumetric flow rate of the moving fluid.…
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Learning how to tune PID controllers is a skill born of much practice. Regardless of how thoroughly you may…
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An electromechanical relay is an electrical switch actuated by an electromagnet coil. As switching devices,…
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“Polyphase” means “many phases,” describing a form of AC electrical system where…
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Data-processing modules within FF systems are known as function blocks. Sometimes these blocks serve merely to…
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At the next OSI Reference Model layer (layer 4) is a set of protocols specifying how reliable communication…
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A laser is a light source emitting waves of light that not only share the exact same frequency (color)…
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Perhaps the most important rule of controller tuning is to know the process before attempting to adjust the…
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Sample sizes of chemical substances are often measured in moles. One mole of a substance is defined as a…
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One of the simplest classes of temperature sensor is one where temperature effects a change in electrical…
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Diagnostic ability is arguably the most difficult skill to develop within a student, and also the most…
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“Radio” systems use electromagnetic fields to communicate information over long distances through…
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Flow, by definition, is the passage of material from one location to another over time. So far this chapter…
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Self-balancing mechanisms consisting solely of a baffle/nozzle detector coupled to a feedback bellows, while…
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A wise PLC programmer once told me that the first thing any aspiring programmer should learn about the PLC…
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