WHERE DO WE GO FROM HERE? (#4 … Part 1)
He landed on Earth. He created. He went back to where he came from. RIP and Thank You David Bowie
Pressure
Pushing down on me
Pressing down on you
No man ask for
("Under Pressure," by David Bowie and Queen, 1981-82)
PREVIEW OF
THE PTOA'S
PROCESS VARIABLE PRESSURE
FOCUS STUDY AREA
Now that PTOA Readers and Students ...
who are reading the PTOA Segments in the intended sequential order ...
have acquired core competency with respect to understanding all aspects of the Process Variable Temperature ...
and more than likely know how to operate temperature-related process industry equipment more efficiently than most currently employed Process Operators do ...
It is time to move on to PTOA's
PROCESS VARIABLE PRESSURE
FOCUS STUDY AREA!
Who amongst us by now doesn't automatically know that "PV" stand for "Process Variable?"
Several dozen integrated PV Pressure topics are going to be presented pretty much in the same format that was used to communicate the several dozen integrated PV Temperature topics.
The first two of the four separate PV Pressure Focus Studies are listed below and are previewed in this PTOA Segment.
The preview of the third and fourth PV Pressure Focus Studies will be featured in the next PTOA Segment.
Naturally, the boundaries between the four separate studies overlap ... because they are intimately related:
- 1. PV Pressure Introduction.
- 2. The Interrelationship of the PV Pressure with the PV Temperature, the PV Flowrate, and the PV Level which will include:
How Pressure Impacts Boiling Points
The Driving Force for Flowrate: Delta P
Delta P and Level Monitoring
The Pressure-Velocity Swap
PREVIEW:
THE PTOA'S PV PRESSURE INTRODUCTION
PTOA Readers and Students must first understand why monitoring, recording, and controlling the PV Pressure is important in the process industries.
The ISA symbols for the PV Pressure instrumentation will also be reviewed.
Most of the Introduction to PV Pressure Focus Study will be devoted to showing PTOA Readers and Students how pressure-related phenomena they have observed all of their lives can be counted on to predict how the real world functions.
Integrated STEM topics that support the PTOA Process Variable Pressure Focus Study Area
By now all PTOA Readers and Student should know that STEM is an acronym for:
- S=Science
- T=Technology
- E=Engineering
- M=Math
The PTOA PV Pressure Introduction Focus Study will reveal how each of the following STEM topics is relevant to how the real world functions:
- Industrial Applications of the PV Pressure.
- ISA Symbols for PV Pressure.
- The Definition of Pressure: P = Force/Area.
- SI and English Units of Pressure Measurement.
- The Definition of Force: F = mass*acceleration.
- The Difference between a Pound of Mass and a Pound of Force.
- The Definition of a Weight Force = mass * the downward pull of gravity.
- The Pressure Created by a Liquid in a Container.
- Density and "Relative Density" (aka Specific Gravity).
- Hydrostatic Head Pressure.
- The Differences Between Atmospheric, Gauge, and Vacuum Pressure.
- Predictable Gas and Liquid Behavior Called "Laws."
PREVIEW:
THE INTERRELATIONSHIP OF PV PRESSURE WITH PV TEMPERATURE, PV FLOW, AND PV LEVEL FOCUS STUDY
How PV Pressure and PV Temperature
Relate to Each Other
Life is all about relationships!
PTOA Readers and Students will learn that the PV Pressure works hand in hand with the PV Temperature to determine the sliding scale of how much of a liquid will move into the gaseous phase and vice versa at the liquid's saturation point.
Hey, don't stress out, Fred!
PTOA Readers and Students have already learned this!
The PTOA has already featured saturated liquids and their vapors.
Remember learning about how Package Boilers generate saturated steam from BFW as was described in PTOA Segment #26 (entitled "Houston ... You Fixed the Problem")?
And "Instrument Techie" PTOA Readers and Students will remember that the fastest responding fluid-filled temperature-measuring systems have volatile liquids as their working fluid ... so that is old news from PTOA Segment #102
In both cases, the temperature at which the vapor-liquid interface existed was emphasized.
Well, it would have been Too Much Information at the time ...but now is the appropriate time to reveal that the pressure maintained in both environments was really important, too!
A Difference in Pressure
Provides the Driving Force That Makes Stuff Flow
The "3 Transport Phenomena" by which the Universe rules were first mentioned in PTOA Segment #57(entitled "Where Do We Go From Here #2).
So ... smart PTOA Readers and Students who are reading the PTOA in the intended sequential order already know that ...
A Temperature Differential (aka "Delta T" or ΔT) must exist before heat can transfer from an area with a higher temperature to an area with a lower temperature.
No Delta T, no heat transfer!
The greater the Delta T, the more heat transfers!
And PTOA Readers and Students have also learned that ...
A Difference in Voltage (aka "Potential Difference" or ΔV) is required before a current can flow through a circuit.
No Potential Difference, no current!
The current will always flow from the highest voltage to the lowest voltage ... and ...
The greater the Difference in Voltage, the greater the current!
The third and final "Transport Phenomena" PTOA Readers and Students will learn concerns a Difference in Pressure (aka "Delta P" or "dp" or ΔP) and Flow (aka Flowrate).
A Delta P is required to create a Flowrate!
The greater the Delta P, the faster the Flowrate!
No kidding!
The Greater the Differential Pressure (Y Axis) ... The Greater the Flowrate (X Axis)
PTOA Readers and Students will learn that the Process Variable Pressure is totally responsible for creating the Process Variable Flowrate.
No Pressure Differential ...
No Flow!
It's that simple!
These two PVs are forever linked together!
The Pressure-Velocity Swap that occurs in flowing fluids describes another fundamental relationship that Mankind has figured out and put to good use ...
like making air travel possible for just one example.
When a fluid's velocity decreases, pressure increases and vice versa.
And ...
since a fluid's Velocity is just a component of Flowrate ...
The "Pressure-Velocity Swap of Fluids" is just a different Pressure-Flowrate relationship!
THE PTOA PV PRESSURE FOCUS STUDY AREA PREVIEW WILL BE CONTINUED IN THE NEXT PTOA SEGMENT ...
©2016 PTOA Segment 0138
PTOA Process Variable Pressure Focus Study Area
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