PROCESS INDUSTRY JARGON RECAP 4-3

"Words are free.
It's how you use them that may cost you." -KushandWizdom

PTOA Segment #101: Instrument Tech Must-Knows: Uses of Liquid-In-Glass Temperature Measurement

No additional process industry jargon was presented in this PTOA Segment.

PTOA Segment #102: Instrument Tech Must-Knows: Uses of Fluid-Filled Temp Measurement (Part 1)

Averaging Bulb: A style of bulb in a fluid-filled temperature measuring device that is longer than a Plain Bulb, and which therefore decreases measurement response lag by providing a greater surface area through which conductive heat transfer can take place.

Case Compensated (Bourdon Tube): A type of technology/strategy used to offset the measurement error that occurs in fluid-filled systems when heat is transferred between the ambient conditions surrounding the capillary and the working fluid inside the capillary.

In fluid-filled systems with short capillaries, case compensation will adequately offset the measurement error that would otherwise occur.

Capillary Bulb: A style of bulb in a fluid-filled temperature measuring device that is helically-wound and thus has more surface area for heat transfer to take place than is available for a Plain Bulb and is also shorter in length than an Averaging Bulb yet still successfully reduces measurement response lag.

Plain Bulb: A style of bulb in a fluid-filled temperature measuring device that is stubby looking and sturdy.

Fully Compensated (Bourdon Tube): A type of technology/strategy used to offset the measurement error that occurs in fluid-filled systems when heat is transferred between the ambient conditions surrounding the capillary and the working fluid inside the capillary.

A Fully Compensated bourdon tube has an entire complementary bourdon tube designed into the instrument that subtracts the bourdon tube movement attributable to ambient conditions so that the net instrument deflection more accurately approximates just the deflection of the measuring bourdon tube.

PTOA Segment #103: Instrument Tech Must Knows: Uses of Filled Temp Measurement (Part 2)

C-Shaped Bourdon Tube: A device that is a transducer because the movement of its tip changes the force applied on its internal walls into a "mechanical motion" ... aka a "deflection."

Helically -Wound Bourdon Tube: A transducer that is fabricated by winding the multiple turns of a Spiral-Wound Bourdon Tube into a stack instead of around the same center.

This bourdon tube design maximizes the sensitivity of process variable measurement because the most mechanical movement (aka deflection) results from an applied force on the interior tube walls.

Spiral-Wound Bourdon Tube: A C-Shaped Bourdon Tube that is redesigned as a more straight and more long tube, then rolled around the same center in wider and wider circles for the purpose of increasing the measuring sensitivity of the instrument because a larger deflection will result from a change in force applied to the internal walls of the tube.

Transducer: A device that changes one type of energy into a totally different type of energy.

PTOA Segment #104: Bend Me, Shape Me, Any Way You Want Me!

Bi-Metallic Strip (Thermometers): A temperature-measuring technology fabricated by welding together the adjacent sides of two metal strips of the same length but widely different coefficients of thermal expansion (for example Brass and Invar). One end of the bi-metallic strip is fixed.

Deflection (of a Bi-Metallic Strip): The mechanical movement of a bi-metallic strip that results when the metal with the greatest coefficient of thermal expansion appears to make the strip "bend" or "curl" upon experiencing a change in environmental temperature.

On-Off Control: A binary control scheme that allows a process variable situation to completely occur or to not occur at all ... as opposed to having a control scheme that allows a process variable to vary between a minimum and maximum and all points in between (aka "Analog Control").

A household smoke alarm being "on" or "off" is a common example of an on-off control scheme because the alarm is either "on" or "off."

PTOA Segment #105: Instrument Tech Must-Knows: Uses of Bimetallic Strips

No additional process industry jargon was presented in this PTOA Segment.

PTOA Segment #106: We Gonna Rock Down To Electric Avenue

Amperes (aka Amps): The units of electrical current.

The units of very small currents are measured in milliAmps (mA).

Current: The flow of electrons in an electrical circuit from a higher voltage area to a lower voltage area. Current is symbolically represented as capital letter "I."

Ohms: The units of electrical resistance. Ohms are symbolically represented as the capitalized Greek letter Omega (Ω).

Ohm's Law: A series of linear relationships (shown below) that define how to determine the magnitude of electrical current (I, measured in amps), electrical resistance (R, measured in ohms), and voltage (V ... but sometimes represented as E for Emf).

The mathematical relationships that appear in all three of the Ohm's Law representations simultaneously predict how each of these defined entities will behave in a simple electrical circuit as one or the other of their defining factors is increased or decreased.

V= I*R I=V/R R=V/I

Potential (of an Electric Circuit): The difference in voltage measured at two different points in a circuit.

The "potential" of a circuit refers to the voltage difference that exists. Current will not flow without a "potential difference." The magnitude of voltage differential (aka potential) determines the amount of current in the circuit.

The device known as a potentiometer is used by Instrument Technicians to measure voltage differential.

(Electrical) Resistance: The amount of volts divided by the amount of current measured at any point in an electrical circuit. Resistance is symbolically represented as the capital letter R.

Resistance is added into an electrical circuit via the electronic component called a resistor for the purpose of controlling the current flowing through the circuit.

Thermocouple: An electrical temperature measuring device that successfully infers a measured temperature because of the linear relationship that naturally exists between the millivolt output generated by the junction of two dissimilar metals upon being exposed to a change in temperature.

Voltage (aka Electromotive Force or Emf): The amount of current (I) multiplied by the electrical resistance (R) at a point in an electrical circuit.

A voltage differential (aka "potential difference" which is usually truncated to just "potential") must exist in an electrical circuit otherwise current will not flow (which is an analogous phenomena compared to a Temperature Differential providing the driving force for heat to flow ... or transfer).

Volts: The units of voltage (as well as Electromotive Force aka emf). For example, the electrical output from a thermocouple is in the form of milliVolts (mV).

You need to login or register to bookmark/favorite this content.