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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Up until this point, we have explored various types of instrumentation diagram, each one making reference to…
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Valves can experience a number of problems, most of them either preventable or repairable. These problems can…
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Perhaps the simplest form of solid or liquid level measurement is with a float: a device that rides on the…
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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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A fluid is any substance having the ability to flow: to freely change shape and move under the influence of a…
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Tube, like pipe, is a hollow structure designed to provide an enclosed pathway for fluids to flow. In the case…
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The reason why a pneumatic control valve’s stem position corresponds linearly to the amount of air…
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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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This section shows some of the many instrument symbols found in different types of technical diagrams used to…
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Self-balancing pneumatic instrument mechanisms are very similar to negative-feedback operational amplifier…
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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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A limitation inherent to pneumatic valve actuators is the amount of air flow required to or from the actuator…
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Multiple accessories exist for pressure-sensing devices to function optimally in challenging process…
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Sometimes we encounter a diversity of instrument signal standards in one control system. Such is the case with…
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Those familiar with industrial instrumentation will find much within the electric power industry remarkably…
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Given the ability of pressurized fluids to transmit force over long distances, it is not surprising that many…
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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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The disadvantages of pneumatic instruments are painfully evident to anyone familiar with both pneumatic and…
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As discussed at the beginning of this chapter, instrumentation safety may be broadly divided into two…
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As previously defined, calibration refers to the checking and adjustment of an instrument so that its output…
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Regardless of valve type, all stem-actuated control valves require some form of seal allowing motion of the…
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One of the most common, and most useful, pressure measuring instruments in industry is the differential…
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A fluid is any substance having the ability to flow: to freely change shape and move under the influence of a…
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The three “elementary” particles of matter comprising all atoms are electrons, protons, and…
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The very purpose of physics is to quantitatively describe and explain the physical world in as few terms as…
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A proximity switch is one detecting the proximity (closeness) of some object. By definition, these switches…
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While 50 and 51 (instantaneous and time overcurrent) relay functions monitor line current magnitude and guard…
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In our first signal characterization example, we tackle the problem of measuring fluid flow through a pipe. To…
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A very common method for directly controlling low flow rates of fluids is to use a device known as a metering…
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All substances are comprised of various elements in various combinations and proportions. Elements may thus be…
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In the United States, the most common language used to program PLCs is Ladder Diagram (LD), also known as…
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As previously defined, calibration refers to the checking and adjustment of an instrument so that its output…
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Self-balancing pneumatic instrument mechanisms are very similar to negative-feedback operational amplifier…
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At the root of successful system diagnosis is a rigorous adherence to scientific reasoning. There exists no…
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Programmable logic controllers are essentially nothing more than special-purpose, industrial computers. As…
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In addition to Ohm’s Law, we have a set of rules describing how voltages, currents, and resistances…
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Disturbances in the liquid tend to complicate liquid level measurement. These disturbances may result from…
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The advent of “smart” field instruments containing microprocessors has been a great advance for…
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AC induction motors are based on the principle of a rotating magnetic field produced by a set of stationary…
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A unique form of technical diagram for describing the abstract functions comprising a control system (e.g. PID…
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