DPHE Process Instrumentation and Automation With References

7/26/2019 DPHE Process Instrumentation and Automation With References

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Double Pipe Heat Exchanger

I. Process InstrumentationA. Resistance Temperature Detector (RTD)

Temperature measuring devices for heat exchangers are most

commonly based on electrical eects, one of which is the resistance

temperature detector. RTD is based on the principle that any material

changes its resistance with temperature. Using a power source, around 1 m

or less current is supplied to the sensor such that the voltage drop due to the

impedance made by the resistor is measured and correlated to determine the

changes in the temperature. The advantages of using resistance

thermometers are its provision for good accuracy and precision, excellent

long term stability and repeatability, and its immunity to electrical noise.

!igure ". #RT!$1%$&$1''$1()$&*$+ Resistance ThermometerSource: Omega Engineering, Inc., n.d.

Specifcations:

aterial of -onstruction -lass / D0 1'' 2hm #latinum wire probes3ire rrangement and -on4guration 5$wire thin$4lm3ire Diameter 1()63ire 7ength &*6

Temperature Range $8' to 8''9- :&&'9- ax at -onnector;B. Temperature Transmitter

Temperature transmitters are electrical instrument that interfaces a

temperature to a measurement or control device. 0t isolates, amplify, 4lter


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noise, lineari


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D?1&&' #E gain F 1G, BR+!F 1.G& B?ampling rate &' samples per second :?#?;2utput Resolution '.&8 ?ystem ccuracy or aximum easured +rror'.11A- :@&''A- to &''A-;'.1%A- :@&''A- to )8'A-;

#ower ?upply 0nHuence Deviation of '.5 from 1' B to 5' BRTD non$linearity@&''A- to )8'A- loo=up table with 1A- resolution implemented in the ?#*5'!irmware to resolve non$linearity of RTD or the -allendar$Ban Dusenrelationship between resistance and temperature. -onnectivity 0nterfaceURT, via a U?/ to URT dongle!orm !actor 1.8))$inch diameter, circular board

C. Current to Pressure (IP) Con!erter0(# -onverter converts an analog signal to a proportional linear

pneumatic output. 0ts purpose is to translate the analog output from a control

system into a precise, repeatable pressure value to control pneumatic

actuators(operators, pneumatic valves, dampers, vanes, etc.

!igure ". 0#&1'$I18 0(# -onverterSource: Omega Engineering, Inc., n.d.

Specifcations:ccuracy '.8J !?

?upply ?ensitivity '.'&8J span per J supply pressure changeKero dLustment 8J !??pan dLustment &'J !?2perating Temp $&' to %'A- :$8 to 1G'A!;-ompensated Temp $1' to G'A- :18 to 1*'A!;

Thermal +ects M'.1J(A- over operating range0nput Resistance M5'' 2hmedia 2il$free, clean, dry air 4ltered to &8 m


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Recommended ?upply #ressure &8 to 5' psig :4ltered air;ax ?upply #ressure )' psig :for 0#&1'$I1&' 158 psi;in ?upply #ressure 1' psi above maximum output pressureir -onsumption :7ea=age; '.'5 scfm!low Rate 1' scfm N G' psiO '.'G PG' psiResponse Time M5' psi Qless than '.8 s :1' to >'J step;O 5' psi & sS

!ailure ode Upon electrical failure, the signal pressure falls to bleedpressure#ressure #ort 1(* !#T+lectrical -onnection D0 *5G8' with screw terminals includedCousing 0#G8 rated, epoxy$painted


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Temperature range $1'A- to V)8A-/R :nitrile;/ody /rass0nternal parts ?tainless steel and brass?prings ?tainless steelDiaphragm W valve disc /R

?eals and pilot disc !#?hading coil -opper-oil insulation -lass !-onnector ?pade plug :cable X G$) mm or X G$1' mm;-onnector speci4cationfor power coil * 3(G,> 3 D0 *5G8', 11 mm, industry standard /for power coil 8(G,>3$)(>3$1&,8(>3 0?2 **'' ( + 1%85'1$)'5, form +lectrical safety 0+- 558+lectrical enclosure protection olded 0#G8 :+ G'8&>;?tandard voltages D- :F; &*B $ *)B

II. Process Automation0n ottingham, United Yingdom, an automation was applied in a seZuence of

heat exchangers for a heat generation plant. ??2 -ontrols supplied the plant

with electric control valves, How regulators, sensors, thermostats, and the TR2B0?

GG'' utomation ?ystem for automation of the heat exchanger seZuence control

loops.+ach heat exchanger is 4tted with an electric control valve in the primary

circuit and a shut$o butterHy valve in the secondary circuit. The How and return

How temperatures are measured in the supply line and in the customer circuit, and

binary operating and fault messages are recorded. These messages are transmitted

to the TR2B0? GG'' utomation ?ystem. The system is scalable with the central

TR2B0? GG1' -#U odule performing the smart plant management. The -#U

module is a freely programmable control unit with &' universal inputs to optionally

record binary or analog signals. 0n addition, twelve binary outputs and eight


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2+E +E0++R0E 0-. :n.d.;. -urrent to pressure converter. Retrieved ay 1),&'1G from

http((www.omega.com(#ressure(pdf(0#&1'.pdf

2+E +E0++R0E 0-. :n.d.;. #latinum thin$4lm resistance thermometers.

Retrieved ay 1), &'1Gfrom http((www.omega.com(pptst(#RT!$1%.html

#R2-+?? 0DU?TR\ !2RU :n.d.;. ?olenoid valves and pressure operated valves.Retrieved ay 1),

&'1G from http((www.processindustryforum.com(article(answers$technical$Zuestions

solenoid$valves$pressure$operated$valves

??2 -2TR27? 0-. :n.d.;. Trovis GG'' automation system. Retrieved ay 1),&'1G from

https((www.samson.de(pdf[en(w'5*G'en.pdfT+I? 0?TRU+T? 0-. :n.d.;. RTD temperature transmitter current loop system.

Retrieved ay 1),&'1G from http((www.ti.com(lit(ug(tidu1)&a(tidu1)&a.pdf

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DPHE Process Instrumentation and Automation With References