Industrial Instrumentation for Continuous Processes

Outline the course structure, reviewing measured properties and units, signals used by instruments, and transducers, to guide selection of devices for temperature, pressure, level, vibration, flow, and composition.

The lecture defines and describes units for length, area, volume, mass, velocity, force, pressure, vibration, temperature, level, flow, composition, and electricity, and introduces unit conversion and dimensional analysis.

Explore how length, area, and volume are defined and measured using SI units and prefixes, and compare common US customary units for land and fluid quantities.

Mass is the intrinsic property contributing to inertia, described in metric and US customary units. Velocity denotes motion, and together with mass forms inertia; a force accelerates or deflects objects.

Explore pressure as force per area, its hydrostatic origins, and the differences among absolute, differential, and gauge pressure, using common units such as pascal, psi, bar, and torr.

Explore vibrations as oscillations around an equilibrium, driven by rotating motion or tense structures, and learn how sound, decibels, and Fourier transforms model periodic motion and frequency content.

Explore how temperature reflects particle movement, from molecular vibrations to skin sensors, and how heat transfers by conduction, convection, and infrared radiation. Compare Celsius, Fahrenheit, Kelvin, Rankine, and absolute zero.

Understand how level measures the height of the interface to estimate phase volume, using ullage and fullage, simple and composite shapes, while noting temperature and deformation effects.

Explore flow principles in continuous processes, distinguishing mass flow from volumetric flow, and understand the units and standard conditions used for gases and liquids.

Explore how composition is reported in bases and units such as molar, mass, ppm, ppb, and mass or volumetric fractions; examine particle size distribution, sieving, and equivalent diameter concepts.

Explore standardized electric units, including coulomb, elementary charges, ampere, volt, and farad, with si prefixes and their relationships in continuous processes instrumentation.

Delve into viscosity, Newtonian and non Newtonian fluids, and flow regimes by Reynolds number, exploring laminar and turbulent behavior and common viscometers.

Explore the basic physics of electricity: define current as the average movement of charges and distinguish direct and alternating currents, applying Ohm's law and series and parallel circuit rules.

Identify measurement errors, understand their types, and learn to calculate and minimize them. Examine calibration, instrument range, noise considerations, and the dynamic response.

Distinguish statistical precision from systematic errors, and assess repeatability and accuracy in instrument data, using averaging, confidence intervals, and considerations like deadband, hysteresis, and discretization.

Learn to minimize errors using maximum and differential error methods, propagate uncertainties in mass and volume to density, and apply significant-figure rules for instrument precision and rounding.

Calibrate instruments using direct known values or certified references, perform replicates across the full range, and test on site to ensure accuracy before operation.

Understand instrument operation across nominal, non deterioration, nondestructive, and destruction ranges. Recognize how fullscale output (FSO), analog output, low and upper range values, present value, and set point guide accuracy.

Analyze how noise from thermal vibrations, instrument precision, and interference affects measurements in continuous processes, and apply filters—from rc filter and digital averages to Kalman and Butterworth—to improve signal accuracy.

Explore how instrument lag and the inertia of the system, via a first order time constant, shape dynamic response, illustrated by a thermometer-like delay and time markers.

Explore how output signals convey information in industrial instrumentation for continuous processes by tracing the signal path, examining signal types by medium and form, and introducing troubleshooting and line representations.

Identify process variables with a sensor, perform signal processing via a transducer to format signals, and send them to controllers, where actuators influence the process through feedback or feed-forward loops.

Analyze signal types by transmission medium and shape, covering electrical 4–20 ma and voltage ranges, pneumatic and hydraulics, wireless options, and major protocols like Hart, Foundation Fieldbus, and Profibus.

Troubleshoot by checking line wear, corrosion, and temperature effects on resistance; verify voltage across two points and interpret current signals (sub-4 mA; over-20 mA) with a clamp-on ammeter.

Explore how drawings represent signals, from bold process flow lines to electric dash lines, waveguides with sigmoidal signals, pneumatic double slashes, backslashes for discrete signals.

Explore how drawings convey instrument information, starting with block flow diagrams and process flow diagrams, then P&ID, and finally loop diagrams, highlighting levels of detail in instrumentation diagrams.

Compare block flow diagrams and process flow diagrams, showing how BFDs focus on streams and process steps without equipment details, while PFDs use symbols for equipment and defined flow information.

P&IDs illustrate process and piping and instrumentation diagrams, showing instruments, lines, valves, and interconnections with legends and tag conventions per ISA, BS, and ISO standards.

Explore loop diagrams, or loop sheets, that map a single control loop's signals, wire colors, tag numbers, and input-output relationships, including 4 to 20 mA proportional and inverse actions.

Explore displacement sensors and transducers, then examine temperature, pressure, vibration, level, and flow instruments, and conclude with composition or analytical instruments.

Explore how displacement sensors and transducers convert forces and displacements into measurable signals, from strain gauges and differential capacitance to Bragg graded optical fiber and inductance sensors.

Explore temperature measurement techniques for industrial processes by examining thermometers and categories such as mechanical thermometers, electrical thermometers, and radiation thermometers.

Explore the three modes of heat transfer—conduction, convection, and radiation—and how thermal conductivity, R value, and Cp govern thermometer placement, grounding, and thermowell service amid safety constraints.

Examine mechanical thermometers that rely on thermal expansion of liquids, gases, or solids—bulb, ideal gas, and bimetallic strip devices for simple, rugged readings.

Explore electrical thermometers used in processes and electronics, including thermocouples, RTDs, and thermistors; learn about active versus passive measurements, and wiring configurations from two to four wires.

Learn non-contact temperature measurement with radiation thermometers, pyrometers, and infrared cameras, guided by emissivity, Planck's law, and infrared optics for detecting hot or cold spots in continuous processes.

Explore pressure instruments for continuous processes, including hydrostatic measurements and aneroic gauges. Learn how pressure measurements based on electrical effects, low pressure gauges, and switches are applied.

Learn how pressure is measured using various instruments, and how hydrostatic effects, transmission lines, calibration, and ASME and CEN codes influence accurate, safe measurements in continuous processes.

Explore hydrostatic pressure sensors, barometers, u-tubes, and McLeod gauges, and explain how liquid density and height measure pressure against atmospheric or vacuum conditions.

Explore aneroid gauges used in industrial instrumentation, including Bourdon, diaphragm, and bellows styles, their mechanisms, capacitance sensors, advantages, and limitations for pressure measurement.

Compare piezoresistive and piezoelectric pressure sensors, detailing active versus passive measurement, materials like doped silicon and zinc oxide, and their dynamic response, calibration, and environmental considerations.

Explore low pressure gauges for industrial processes, from near atmospheric gauge readings to deep vacuums, including Pirani, McLeod, hot/cold cathode ionization, and radiation gauges.

Explore pressure switches used in continuous processes, including Bourdon gauges and spring-activated types. Note deadband and hysteresis from friction, and manual screw adjustments for normally open or closed states.

Introduce level instruments and survey visual, mechanical, electromagnetic, electric, and vibrational measurement methods as part of level measurement fundamentals for continuous processes.

Explore level measurement in continuous processes, focusing on hydrostatic principles, drift corrections from deformation, corrosion, and fouling, and alarms, plus devices from bubbler tubes to radar, ultrasonic, and capacitive sensors.

Visual measurements use gauging rods and wires, side rulers, and sight glasses to read vessel levels, best for small flows and discontinuous measurements, with emphasis on verticality and contrast.

Explore mechanical measurements for continuous processes, including hydrostatic devices, bubble sensors, weight devices, and various floats, with notes on differential versus absolute pressure and density effects.

Explore electromagnetic measurement methods for continuous processes, including radar and laser time-of-flight techniques, Beer-Lambert law absorption, and slow neutron probes for level measurement in vessels.

Explore electrical level measurement methods using conductivity, capacitive sensors, and ram's horn switch, highlighting how liquid composition, dielectric permittivity, and temperature gradients affect accuracy and practicality.

Learn vibration-based sensing using ultrasound time-of-flight and damping switches with tuning forks and paddle wheels. Understand how speed of sound depends on elasticity, density, temperature, and how coatings affect performance.