Fundamentals of Industrial Control WEEK 4. This week : Temperature Measurement Terminology Temperature Sensing Technology . How was it last Week?. Recap of last Week: Remember the terms? Types of Pressure Sensors When and Where to Use What We Need to Use Did we miss any?
This week : Temperature Measurement
Temperature Sensing Technology
Recap of last Week:
Remember the terms?
Types of Pressure Sensors
When and Where to Use What We Need to Use
Did we miss any?
Did You Read Up?
Pounds per square inch Gauge
= reference to atmosphere on earth
Pounds per square inch Absolute
= Reference to “Space Vacuum”
PSIG= PSIA+ 14.7
Bourdon tubes are circular-shaped tubes with an oval cross-section. The pressure of the media acts on the inside of this tube which results in the oval cross section becoming almost round. Because of the curvature of the tube ring, the bourdon tube bends when tension occurs. The end of the tube, which is not fixed, moves, thus being a measurement for the pressure. This movement is indicated by a pointer. Bourdon tubes bent at an angle of approx. 250° are used for pressures up to approx. 60 bar.
For higher pressure, bourdon tubes are used which have a number of superimposed coils of the same diameter (i.e. helical coils) or helical-shaped coils (i.e. helical springs) at one level. Bourdon tubes can only be protected against overload to a limited extent. For particularly difficult measuring operations, the Wika pressure gauge can be provided with a chemical seal as a separation or protection system.
The pressure ranges are between 0...0.6 and 0...4000 bar with a reading accuracy (or accuracy class) from 0.1 to 4.0%.
Inner ScaleOuter Scale
Inner ScaleOuter ScaleFigure IntervalsMinor Grad.Figure IntervalsMinor Grad.
0/9 oz./in.2 0/15 in. H2O 1 0.2 5 0.2
0/20 oz./in.2 0/35 in. H2O 5 0.5 5 0.5
0/35 oz./in.2 0/60 in. H2O 5 0.5 10 1
0/60 oz./in.2 0/100 in. H2O 10 1 10 1
Size63mm (2.5"), 100mm (4")
Case304 stainless steel, dry (1008A), or liquid filled (1008AL)
Ring304 stainless steel, crimped
DialBlack figures on white background, aluminum
Bourdon tube"C" shaped bronze (vac.-600 psi and compound) Helical bronze (1000 psi-6000 psi) Helical stainless steel (10,000 psi-15,000 psi)
MovementPatented PowerFlexTM with polyester segment
SocketBrass, with O-ring case seal
RestrictorBrass throttle plug 0.013" orifice in all ranges (except vacuum and 15# psi ranges)
Connection.25 NPT lower and back
RangesVac. thru 15,000 psi and compound. Equivalent metric ranges available
AccuracyASME B40.1, Grade B, 3-2-3
Operating temperatureDry gauge: -40° F to 150° F Glycerine filled: 20° F to 150° F Silicon filled: -40° F to 150° F
CaseSealed case, field-fillable (LJ) Silicone filled (GV)
Mounting hardwareU-clamp (UC), front flange (FF), retrofit flange (RF)
SocketThrottle plugs 0.007", 0.02", 0.063"
are .5% accuracy
Pressure psiCompound psi
0/15 30" Hg/15 psi
0/30 30" Hg/30 psi
0/60 30" Hg/60 psi
0/100 30" Hg/100 psi
0/160 30" Hg/150 psi
0/200 30" Hg/300 psi
0/600 30/0 in. Hg
0/800 34/0 ft H20
0/5000 NOTE: Equivalent standard kg/cm2, and kPa metric ranges are available.
Expansion of An Alcohol based susbstance
to expand within a fixed volume area in a direct correlation to a fixed mechanical scale
Similar to a spiralhelic pressure gauge in its Construction
Standard DIN Curve
1% at best!!
Connectors - Electrical connections can gradually loosen the connector, and generate heat as a result of repeated heating (expansion) and cooling (contraction), and/or dirt, carbon deposits, and corrosion. A noncontact thermometer quickly determines temperature increases that indicate serious problems.Electric Motors - To maintain lifespan of motors, inspect supply power connections and circuit breakers (or fuser) for equal temperatures.Motor Bearings - Detect hot spots and schedule repairs or replacements before problems lead to equipment failure.Motor Winding Insulation - Prolong the life of winding insulation by measuring its temperature.Phase-to-Phase Measurement - Check cables and connectors for equal phase-to-phase temperatures for induction motors, large computers, and other equipment.Transformers - Check the windings of air-cooled units for hotspots that indicate winding flaws.
Non-contact IR thermometers are quickly becoming an integral part of HACCP routines. Many food service professionals are familiar with the food safety procedure known as HACCP and which is now mandated for meat, poultry, and seafood production plants, as well as fruit and egg process plants. HACCP looks at the flow of food as it travels in and out of the Temperature Danger ZoneAlso Food and Drug Administration (FDA) suggests the use of infrared thermometers in the 1999 Federal Food Code, Annex 4, Section 8. and recognizes that quick scans of the surface temperature with an infrared thermometer facilitates general food safety:"The infrared thermometer quickly registers surface temperatures, which facilitates general food safety system surveillance by allowing the scanning of numerous food temperatures over a short period of time." MiniTempFS assures the greatest accuracy in the food critical zone called Danger Zone where harmful bacteria grow most rapidly. The term Danger Zone describes temperatures above 40°F (4.4°C) and below 140°F (60°C.) If potentially hazardous foods such as dairy products, shellfish, meats, etc., remain within this range for more than four hours, foodborne bacteria can grow. While precautions are taken and enforced by health and food safety inspections, the owners, operators, and service personnel bear every day responsibility of providing healthy quality food which means an awareness and plan of action to ensure foods are out of the Danger Zone.
Infrared Noncontact Thermometers Are Effective Equipment Performance Monitoring & Diagnostic ToolsNoncontact thermometers give you instant, accurate temperature readings of most key HVAC components. Diagnose duct leakage, supply and return air temperatures, plumbing lies, and other heat-related problems with infrared thermometers.Technicians quickly and efficiently gather temperature data from these applications:• Room Balancing: scan walls for unbalanced temperatures• Duct Work: scan the surface of ductwork to reveal temperature spikes and poor insulation• Steam Distribution Systems: diagnose blown or plugged steam traps from a safe distance• Furnace Performance: test furnace performance by checking the flue temperature• Supply/Return Registers: evaluate temperature differential between supply/return registersOther Applications:• Check for coil sweating of condensate lines• Check emergency relief value temperature• Scan wet wallboard for water leaks• Measure existing air from a coil and at a supply air grill
Homework design 5 loops combination of pressure and temperature applications……..!
Next Week Process ControlPages 199-225
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