Measuring Instruments Project

Alfonso FigueroaTeam F4

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Name: Alfonso Figueroa _ Team: F4_____________

1. Self Evaluation Assessment Symbol/Color α Date 3/22/15_________

2. Instr/Grader Evaluated by Assessment Symbol/Color Date _______________

Yes No Self-Regulation Issues (to be completed by Instructor/Grader)

A. The assignment was submitted on time

B. The top sheet of the submitted assignment was this checklist with all Features self-assessed

Required ItemsYes No Checklist Item

α 1. The work meets all expectations of the Assignment Formatting document.

α 2. There is Pre-Reflection and a Post-Assignment Reflection written in the first person.

α 3. The work is professional and ethical

α 4. All quoted and non-original work is properly cited

5. All required items, (with all subtasks), are present.

α a. Task 1 (temperature measurement, 3 methods)

α b. Task 2 (pressure measurement, 3 methods)

α c. Task 3 (flow rate measurement, 2 methods)

α d. Task 4 (concentration measurement, 2 methods)

α 6. There is a references section, appropriately and consistently formatted

Comments on the quality of the expected features and/or how they might be improved

1Figueroa_Assignment_2


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Rating*0 - 5

Rated Features: Rate the Quality of each of these Features: 0 = Missing; 1 or 2 = Weak, 3 = OK/Good, 4 = Superior, 5 = Clearly outstanding

5 7. Rate the quality of the information provided for Task 1 (All elements present; thorough, concise, presented in clear sentences and paragraphs)There is good information about how electrical signals can be applied to the non-electrical instruments. There are two extra facts for each instrument in the additional information. The formulas derived go in an organized process were every step is clear and concise. There is history about McLeod in the McLeod Gauge section. The illustrations correlate to the formulas precisely

5 8. Rate the quality of the information provided for Task 2 (All elements present; thorough, concise, presented in clear sentences and paragraphs)All information is in good order and two additional facts are under additional information for each instrument. I also put information for a company that has produced a camera for IR pyrometers that can display thermal images.

5 9. Rate the quality of the information provided for Task 3 (All elements present; thorough, concise, presented in clear sentences and paragraphs)Nasty and long equations are derived where the reader is able to understand each step for it being clear and to the point. Two extra facts for each instrument where there are comparisons with other instruments. Clear illustrations that show where each variable correlates too from the formulas.

5 10. Rate the quality of the information provided for Task 4 (All elements present; thorough, concise, presented in clear sentences and paragraphs)Two extra facts are given under additional information for each instrument. The graphs are illustrated properly to show how the equations relate to them.

5 11. Rate the overall technical quality of the work (Appropriate technical level and tone; useful to a non-expert)This paper is written in a straight forward manner where nothing but facts are written. Besides the equations, this can be understood by a non-expert. The writing is to the point and the illustrations give the user a good idea of how a certain instrument works.

5 12. Rate the quality of the overall presentation of the work (in addition to meeting all format requirements, work is neat, of appropriate size, etc.)Everything is in the order that was required from the assignment 2 guidelines. Everything is clean and no parts are in the wrong order.



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Rating*0 - 5

Rated Features: Rate the Quality of each of these Features: 0 = Missing; 1 or 2 = Weak, 3 = OK/Good, 4 = Superior, 5 = Clearly outstanding

5 13. Rate the quality of the Pre-reflection and Post-assignment Reflection (addresses issue as described in Assn_reqs.doc)The pre and post reflections were written in their designated times. Everything written shows how I truly felt about the assignment. Whether it be my weaknesses or strengths, every detail of how I viewed this assignment is truly me.

Extra Credit* (each can add up to 0.15 to Rated Item Average)

Yes Describe features of your work that you believe qualify for “Extra Credit”

1.

2.

* If you self-assess rated item at 4 or 5, or claim Extra Credit, you MUST explain WHY, and ideally explain why using the reasons given in the course’s Assessment/Grading document.

Results of Initial Assessment (to be completed by Instructor/Grader)

If substantially incomplete (NC), grade is 0; if any requirements not met or average of Rated features less than 2.8, grade is 50 (NI); otherwise, Grade = average of Rated Features + Extra Credit

E M NI NC

E, all Yes’s for Required Items, no Rated Items below 3, Rated Item average above 4.6

M, all Yes’s for Required Items, Rated Item average at or above 3

NI, any No’s for Required Items or Rated Item average below 3

NC, little or no work to be assessed; more than 3 No’s; Rated item average below 1.8



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Assignment #2

Pre-Reflection

I will start doing this assignment on February 9, 2015 for I was not assigned to do any full or non-technical reports. I will be doing this assignment for Professor Burrows and I will be doing it to learn the different types of measuring instruments. This assignment will help meet my goals in being able to be more effective in reading off measurements with little to no error in lab. Skills I shall be using will range from mass transport phenomenon to fluid mechanics knowledge for instruments that read flow rates. Strengths I plan on using are my effective research skills where I can use them online and at Noble Library. Weaknesses that I may come across could be that my fluid mechanics knowledge is a little rusty but a refresher can help. How I see this all coming together is that I gather all my newly found instruments in an organized manner. Knowing these new instruments and understanding fully how they work will give me a better understanding of reading data accurately.



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TASK 1

For this task three different instruments that measure temperature will be researched with great detail. This includes finding the equations that correlate with each instrument, the advantages/disadvantages, and even detailed pictures.

Mercury Thermometer

The physics involved in this type of thermometer is volumetric expansion. This is caused by a change in temperature which correlates to the liquids coefficient of expansion and which then forces the liquid to expand in a linear tube. Wherever the top of the fluid head ends up stopping at in the vessel is where the temperature is read off from.3

Equations that govern physics

Thermometer with bulb acting as a reservoir is gained by1

(1)

∆ VV

=∆ TT

Where V is the volume of mercury in reservoir, ∆ V is the change in volume, T is the temperature in K, and ∆ T is the change in temperature.

The change in volume is related to the rise in the column

(2)

∆ V =A ∆ L

Where Ais the area of a circle and ∆ L is the change in length

Plugging (2) into (1) comes out as

(3)

∆ L=V ∆ TAT



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Formula for thermal coefficient of expansion (β=αV ¿ is as follows3

(4)

β=αV = ∆ VV ∆ T

Rearranging (1) and subbing in β for T

(5)

T=∆ T∗V∆V

= 1β

Now subbing (5) into (3) and knowing that VA

=L° comes out as4

∆ L=L°∗∆T∗β

This is the formula that governs the physics of a liquid filled thermometer

Figure 1: Mercury Thermometer



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A manufacturer of mercury thermometers is Thermco’s. A thermometer with a catalog No. of ACC001C with a length of 327 mm has a range of -20 ℃ to 150℃. The material used for the thermometer is annealed glass which has been aged so that there is a minimal amount of error when reading temperature. This Thermometer meets the ASTM standards for accuracy tolerance and uncertainties.2

An advantage of a mercury filled thermometer is that Mercury can have a range from -35 ℃ to 510℃. As compared to alcohol’s range from -80℃ to 70℃, this shows that mercury has better application in industry. It has a broad appeal and is applicable in not only industrial and laboratory use, but also in home and medical fields.3

A problem that can occur is just from reading the thermometer itself. If one is reading the thermometer from above or below a misreading in temperature will occur. For no error to occur, one must keep their eye level the same as the top of the mercury column. Errors can occur through glass aging over years of use. This is caused from all the times the glass is heated to high temperatures and then cooled. This causes the glass bulb to contract slowly so that the zero mark ends up being too low on the stem.3

The mercury in the glass thermometer is a good electrical conductor which can be used to generate electrical on and off switches. Two platinum wires can be bored on the head and bottom of the thermometer where they meet at an electrical circuit. The circuit is limited to 25 mA where the current can be used to operate an electronic control circuit. These are called contact thermometers and are used in a variety of settings including fluidized beds and incubators. Temperature can then be controlled by increments of 0.1 C˚.3

The reason mercury is used in glass thermometers is because mercury had a cubical expansion eight times that of glass. This is the reason why mercury will expand in the tube at a much faster rate compared to the negligible expansion of glass. There are some industries where they abide from using mercury and use other liquids like alcohol, toluene, etc. This is so for if a bulb broke the mercury can cause damage to products.3

Infrared Pyrometer

The infrared pyrometer is capable of measuring temperatures with no contact. It measures radiation coming off any object that is in the infrared pyrometer’s temperature range. The radiation goes through the lens of the infrared pyrometer where it is focused in an infrared detector. The kind of infrared detector used is a semiconductor which projects a current from the wattage of radiation. Depending on the waveform emitted together with the Stefan-Boltzmann law the temperature can be emitted from the output amperage.22



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Equation that governs Physics22

Q=εσ T 4

Where Q is the thermal radiation, T is the temperature, σ is the Stefan-Boltzman constant, and ε is the emissivity of object through Stefan-Boltzmann law

Figure 8: Infrared Pyrometer22

A manufacture that produces infrared pyrometers is Optrics. The infrared pyrometer optrics CS LT is capable of measuring temperature levels from -40 ˚C to 1,030 ˚C. It is capable of gathering multiple employments of infrared measurement points at high precision. At standard temperature ranges it has an accuracy of ∓ 1.5 ˚C.23

A great advantage of the infrared pyrometer is that it is a non-contact device. This means that safe measurement readings are possible from thermoforming, blow molding applications, and more. It is capable of having fast response times since the infrared detector is a semiconductor. The temperature is also transmitted as radiation which compared to heat conduction is much faster.22

It is not capable of absolute accuracy with a measurement at 200 ˚C, the accuracy comes off at ∓ 2 ˚C.When measuring heated polymer, temperature is dependent on the emissivity of the polymer. The emissivity ends up varying with every type of polymer, filler, and color. This means it has to be calibrated for every different type of emissivity outputted which can come out very time consuming.22

It is already capable of reading electrical signals so does not need any modifications. Infrared pyrometers can be mounted by a process line where it is aimed at a given point. There are also handheld devices which can be used for maintenance, diagnostics, quality control, and spot measurements.24 Lumasense technologies inc. developed an infrared pyrometer that has a built in camera. This camera can record infrared readings which can then be outputted on LumaSense's



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InfraWin software via usb. A thermal image is then produced on the software where temperature, data logging, and analysis are outputted. This is ideal for knowing the temperature of an object and knowing the uniformity across that object’s temperature.25

Silicon Bandgap Temperature Sensors

The Silicon Bandgap Temperature Sensors are similar to that of transistors and integrated circuits. It is capable of measuring temperature in electronic circuits. How it functions is that the forward voltage of the sensor is temperature dependent. Comparing band gap at two currents, the change in the band gap voltage can thus be used to calculate temperature.33 Also by tuning resistors and number of bipolar junction transistors results in direct relationship between voltage of PTAT and temperature.36


(1)

V BE=V G0(1− TT 0 )+V BE 0( T

T 0 )+( nKTq ) ln( T 0

T )+( KTq ) ln ( IC

I C0 )Where T is the temperature in Kelvins, V G0 is the band gap voltage at absolute zero, V BE 0 is the band gap voltage at T 0 & I C0, V BE is the band gap voltage, IC is the current, K is the Boltzmann’s constant, q is the charge on electron, and n is the device-dependent constant

Only having to compare band gap voltages at two different currents reduces equation (1) to33

(2)

∆ V BE=(KTq ) ln( IC

I C0 )Tuning in resistors and BPTs results in direct relationship between VPTAT and temperature36

(3)

V PTAT=2 R 1(V BE−V N)

R 2=2

R 1R 2

∗KT

qln (N )

Where V PTAT=¿ band gap voltage at PTAT, R=¿ resistance, N=¿ number of BPTs



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Figure 12: Silicon Bandgap Temperature Sensor36

A manufacturer that produces silicon bandgap temperature sensors is NXP. The KTY82 silicon temperature sensor is able to read a range of -55 to 150 ˚C. With a positive temperature coefficient and fail-safe behavior, optimal precision is endured. With long-term stability and reliability, high accuracy is achieved. 35

With the sensor being made out of silicon, it is capable of being stable for long periods and under harsh conditions. The device does not need to be calibrated in any given condition unlike thermistors and thermocouples which need to be recalibrated consistently.34 With great advantages though come with some disadvantages. When the temperature goes above 250 ˚C, leakage currents become large and mess up data.33 If one ever tries to calibrate the device then corruption can occur.34

It is already capable of reading electrical signals so does not need any modifications. What it can be used for in circuits is a way to notify when the system is close to overheating. It is used in cars to control heating, air-conditioning, engine oil, coolant, and transmission.32

For task 1 I would have started off with using a temperature device described by Professor Burrows. Then I started to research for a temperature device that can read off solids. The last instrument was then researched regularly through websites and Knovel.



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Task 2

For this task the same principles are applied but now for pressure readers. Three pressure instruments will be researched. One of the instruments has to be able to measure pressure readings from below 100 torr and one is able to measure liquid pressure.

McLeod Gauge

Physics involved in this instrument are similar to that of a manometer. The difference is that one end is sealed and the other end can be opened and closed. An unknown fluid is put in the tube where a piston is put atop the mercury. The mercury is pushed up through the column where the column’s volume is then calculated from the height of the mercury. All of the physics fundamentally correlated to the Boyle’s law which calculates P unknown.5


Gauge is based off Boyle’s Law

(1)

Pu V u=Pc V c

Where Pu is the unknown pressure of fluid, V u is the unknown volume of fluid, Pc is the compressed pressure of fluid, and V c is the compressed volume of fluid

The compressed volume of fluid correlates to height to height of mercury and area of tube

(2)

V c=hA

Where h is the height of mercury and A is the area of tube

Plugging into (1)

(3)

Pu V u=Pc (hA)

The compressed pressure of the fluid is related is related to the manometer equation

(4)



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Pc=Pu+hρg

Where h is the height of mercury, ρ is the density of mercury, and g is gravity

Inserting into (3)

(5)

Pu V u=(P¿¿u+hρg)(hA)¿

Rearranging in terms of Pu results in

(6)

Pu=h2 ρgA

(V u−hA)

Since for the most part V c ends up being smaller than original volume, equation reduces down to5

(7)

Pu=h2 ρgA

V u

for hA≪V u



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Figure 2: McLeod Gauge7

A manufacturer of McLeod Gauges is HYVAC Products, Inc. A McLeod gauge with a catalog number of 94163-020 that contains 14 ml of mercury has a lowest reading of 10 -6 and has a pressure range of 0 – 10-3 torr. Since measurement follows Boyle’s Law volume per unit length of tube is found with high precision. Once the correct volume is formed during manufacturing, little can change its calibration so it can be used as a reference standard. The instrument measures non-condensable permanent gases correctly but errors can occur if vapor is present.6

The error that is possible with a McLeod gauge is only at ∓1 %. Because of this it is used as a standard for other gauges to be calibrated to. It is capable of measuring pressure from 0 torr to all the way down to 10-4 torr. Even lower pressures can be measured if pressure-dividing techniques are applied.5

It can be easy for water and mercury vapors to cause error to the measurement reading. A way to bypass vapors that can occur is to do a nitrogen cold trap so non-condensable gases are only being measured.6 During the compression stage, there is a chance that condensation can occur from the low-pressure gas.7

It can be a challenge to accurately measure where the head of the mercury ends up leveling at in the tube causing misreading’s. A way to bypass this is by adding a Tungsten wire through the top of the head of the gauge. When the mercury passes the tip of the wire, the wire connected to a relay activates an electromagnet that makes a clicking sound. The level where the mercury is at



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is then recorded by the observer. Once the mercury goes down another click is made and the observer then records the level. The levels are then averaged giving a higher accuracy of measuring pressure. The electromagnet is operated at low voltages and current is limited by non-conductive resistance at a low value.9

Electronic replacements have come into the market but the McLeod gauge is still more common in labs today. McLeod was an Anglican and he and his colleagues made a declaration that objected against science research going against views of religious believers. This was during 1864 where science and religion was in high debate where the declaration ended up making little to no impact. Even though the declaration made little impact McLeod would be remembered for his scientific papers in the Royal Society and of course, his gauge.8

Piezometric Tube

The Piezometric tube sticks out on the side of a tank where it is capable of reading pressure at a certain point. The height of the liquid column is then measured where it is proportional to the liquid’s specific weight. This then can calculate the pressure at a specified point.17

Equation that governs physics17

P=wh

Where Pis the pressure at a certain point, w is the specific weight of liquid, and h is the height of liquid in tube

Figure7: Piezometric Tube17

A manufacturer of the piezometric tube is BAT. This tool is capable of real time pressure readings where range is varied depending on units being used. It has an internal pressure sensor where pressure can be read with spot on precision. BAT provides high accuracy combined with flexibility and long-term reliability.20



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Since they are cheap and easy to manufacture, they can be replaced with little to no effort.

Installation only requires a low amount of material technical requirements.19 With great advantage though come with some disadvantages. Pressure readings are only capable in gauge reading and cannot reach negative values of pressure.18 It is not capable of reading gas pressures because a gas forms no free surface.18

The company BAT added a pressure sensor to the device where it is capable of measuring pore pressures with great accuracy. The pressure value that is displayed can also be switched into preferred units.20 Piezometric tubes can be used to measure underground water pressure.21 The height of the liquid in the tube can also measure the piezometric liquid levels.17

Strain Gauge Pressure Sensors

Strain is the deformation of a material where stress is the force that causes the deformation. The strain can be measured by a strain gauge device. There are multitudes of wire that are connected to a stationary frame and a movable armature. The armature is connected to pressure-sensing bellow. The littlest pressure changes are sensed by the wire where resistance is changed when stretched.37

Equations that governs physics

Resistance of a metal wire

(1)

R0=rl0

A0

Where R0 is the initial wire resistance, r is the resistivity of wire, l0 is the initial wire length, A0 is the initial cross-sectional area

When wire is stretched, volume is constant

(2)

V=l 0 A0=(l0+∆ l ) ( A0−∆ A )

Where V is the volume, ∆ l is the change in wire length, and ∆ A is the change in cross-sectional area



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Because of this change in A and l, resistance changes as well

(3)

R=r(l0+∆ l )

( A0−∆ A )

Combining equations (2) and (3) results in

R ≈ rl0

A0 (1+2 ∆ ll0 )

Which reduces to the change of resistance37

∆ R ≈ 2 R ∆ ll0

Figure 13: Strain Gauge Pressure Sensors37

A manufacturer that produces Strain Gauge Pressure Sensors is HBM. The LY series are designed for strain measurements in one direction where the resistance ranges from 120, 350, 700, and 1000 ohms. The measuring grid contains constantan where the measuring grid carrier is made of polyimide providing good precision. The pre-wired strain gauges no longer need to be soldered to strain gauges which reduces error thus increasing accuracy. 41

It can be used for monitoring different structures including bridges and buildings. The tool can be installed under extreme conditions which include radiation spots, areas with great vibrations,



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and temperature ranges from -269 ˚C to 1300 ˚C.40 With great advantage though come with some disadvantages. When installing the instrument, it is vary labor intensive.40 When it is applied to a new area it has to be calibrated.39

It is already capable of reading electrical signals so it does not need any modifications. They are used in research and development which includes automotives, aerospace, medical, and more.40

There are also mechanical strain gauges but are bulky, have long gauge lengths, and are limited in actual application.38

For task 2 I started off with researching for a pressure device that can read pressures below 100 torr. My next step was to research for a pressure device that can read off liquid pressure. Then I would finally use an instrument that can measure pressure described by Professor Burrows.

Task 3

Just like task 1, measuring instruments will be researched for the following specifications. This time though the instruments that will be researched for will be for measuring flow rates. Two must be researched where one can read liquid flow rates and one can read gas flow rates.

Liquid Turbine Meter

A Liquid turbine meter measures velocity from fluids that flow past a free-turning rotor. The liquid goes through the angled rotor at an angular velocity so that the rotation mimics the flow rate. Readings of the rotor come off from mechanical gearings or magnetic pickup. There is an ideal formula that is derived for no velocity loss. Another formula is derived for velocity change where torque is applied to make the turbine rotate.10, 11


For no velocity loss the ideal angular velocity is proportional to velocity gives a trigonometric formula

(1)



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ωi

V=

tan (β)r

Where ωi is the ideal angular velocity, V is the velocity of flow, β is the angle between pipe axis, and r is the root-mean-square of inner and outer radii of blade.

The formula for r

(2)

r=√ R2+a2

2

Where R is the radius of turbine and a is the radius of blade

Now the formula for a changing velocity which now applies a torque to turbine

(3)

T=∫a

R ρAV (2 πr )r (r ωi−rω)

π (R2−a2)dr

Where T is the torque, ρAV is the mass flow rate of liquid, and ω is the angular velocity

Which reduces down to

(4)

T=ρAV ( ωi−ω )(R2+a2)

2

Subbing equation (2) into (4) results in

(5)

T=ρAV (ωi−ω)¿

Now rearranging in terms of ω



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(6)

ω=ωi−T

ρAV ¿¿

Now subbing (1) into (6) and then making ω proportional to V

(7)

ωV

= tan (β )r

− TρA V 2 ¿¿

Since turbine is rotating at constant speed, torque has an equal amount of resistance torque

(8)

Fd=ρ V 2Cd S

2≈ 0.074 R e

−0.2 ρ V 2 S

Where Fd is the sum of drag force on each blade, Cd is the drag coefficient, S is the distance between blades, and Re is the Reynold’s number

The formula for T then becomes

(9)

T=n( R+a2 ) Fd sin (β)

Where n is the number of blades

Plugging in (8) for (9)

(10)

T=n ( R+a )0.037 Re−0.2 ρ V 2 S sin (β)

Now plugging (10) into (7)



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(11)

ωV

=tan (β )

r−

n ( R+a ) 0.037 Re−0.2 S sin (β)

A ¿¿

Rearranging in terms of VA which is equivalent to Q, we find our volume flow rate formula11

(12)

Q=VA=ω A2¿¿

Figure 3: Liquid Turbine Meter General11



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Figure 4: Liquid Turbine Meter Fins11

A manufacturer that produces liquid turbine meters is Liquid Controls. A liquid turbine meter precision series with sizes between ¼ ’’ to 12’’ can have flow rates from 0.5 to 12,500 gpm. Flow streams are measured from precision-crafted rotor blades. The rotors supported by precision bearings give high precision for years to come. Offering high-accuracy, turbine flow meters provide years of consistently accurate trouble free service. The accuracy ends up being around +/- 0.5% linear and is also capable of +/- 0.25% or +/- 0.15%.12, 13

The meter itself contains good accuracy over a linear range. The meter cost is medium also but a total meter station is cost effective because of high flow rate for given line size. The flowmeter has an electronic output available at a high resolution rate which can prove possible in a limited time period.10 With great advantage though come with some disadvantages. The turbine meter can have large errors produced if ever a secondary fluid is present. Like for instance, for a liquid only turbine which contains 5% air can produce up to 50% error in measurement.5 Depending on a liquid’s viscosity, meters may need different proof curves for different viscosities.10

Already generates electric signal through the electronic output where flowrate can be displayed. There are liquid turbines that can be used to measure high flow rates which is called the helix meter.10 Oil industry uses liquid turbine meters where gas/oil mixtures are common. Since high errors can occur with two different fluids, special procedures are still being developed to avoid large errors.5



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Transit time Liquid/Gas Ultrasonic Flowmeter

This flowmeter is capable of measuring flow rates by use of ultrasonic transducers. There is an angled transmitter that emits ultrasonic energy through the pipe which travels to the receiver. Beams that are travelling upstream and downstream sense the time difference caused by a flowing fluid. The difference in time sensed by the transducers thus allows the velocity to be calculated. Time shifts are measured are usually by a frequency change. This method is used because of it using a high-precision electronic device being able to measure velocity of sound. The electronic devices used are multiplexes which connect to the receiver and transmitter where one ultrasound element is needed in each transducer.5


Forward transit time and backward transit time formulas are given

(1) & (2)

T f =L

C+Vcos(θ);T b=

LC−Vcos(θ)

Where T f is the forward transit time, T b is the backward transit time, c is the velocity of sound, V is the flow velocity, L is the distance between transmitter and receiver, and θ is the angle of ultrasonic beam

The time difference between (1) and (2)

(3)

∆ T=T b−T f =2 VLcos(θ)

c2−V 2 cos2 (θ )

The c value has to be known to solve but using frequency instead will make solving for V simpler.

Frequencies of forward and backward pulse times

(4) & (5)

F f =1

T f=

c−Vcos (θ)L

; Fb=1Tb

=c+Vcos(θ)

L

The frequency difference between (4) and (5)



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(6)

∆ F=Fb−F f =2Vcos(θ)

L

Now V can be calculated without needing to know value of c

Rearranging (6) in terms of V results in5

(7)

V= L ∆ F2cos(θ)

Figure 9: Electronic devices to determine frequencies5

Figure 10: Transit time Liquid/Gas Ultrasonic Flowmeter26

A manufacturer that produces Transit time Liquid/Gas Ultrasonic Flowmeter is Flexim. The FLUXUS G601-The Portable Gas Flow Meter can be used on pipe diameters that range from 0.4 inches to 43 inches. From these given diameter sizes, the flow velocity can range from 0.03 ft/s to 100 ft/s. It has automatic loading of calibrated data and transducer detection reducing set-up



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times which provide precise long-term results. There is 1% to 3% of reading ∓ 0.03 ft/s depending on application. There is also 0.5 % of reading ∓ 0.03 ft/s if field is calibrated.27

Since it is clamped on the outside of the pipe, that means that there is no obstruction in the flow path which also means no pressure drop. Having the ability to clamp on the outside of the pipes, there are portable versions where they can be used for field analysis and diagnosis.26 With great advantage though come with some disadvantages. It is very expensive to have a high initial set up cost and for the complexity of the electronics.5,26 Velocities that vary over a wide range of Reynolds number are not ideal for single pass (one-beam) models.26

It is already capable of reading electrical signals so no further modifications are necessary. There is another ultrasonic flowmeter called a Doppler Shift flowmeter. The Doppler Shift needs to be able to sense scattering elements in the fluid to be able to get a reading of flow, as compared to that of the transit time flow meter which can only read flow of clean and clear fluids.5, 26 There are multiple beam versions where it can overcome the disadvantage of single beam versions not being capable of reading varying velocities.26

For task 3 I started off by researching for a liquid flow rate meter which I found out that Professor Burrows actually ended up discussing in a future class. I of course still used the instrument that I found but I had to do research again which can come off as a nuisance. The last flow meter that I found was capable of reading gas but also liquid flow rates.

Task 4

This task ends up resembling tasks 1 through 3 with the same guidelines. The instruments this time though will be that of ones that can measure liquid levels in a vessel. Two will have to be researched where the professor did not go over these types of instruments in class.

Capacitive Liquid Level Detectors

Capacitors that measure liquid levels can come in different forms. A common capacitor used in measuring non-conductible materials is where there is a metal rod in the center of the tank. The rod acts as one plate and the other plate comes off the tank wall forming the capacitor. When liquid rises in the tank, the gas is displaced by the liquid which contains a different dielectric constant value. The capacitor then senses the change in dielectric constants where a new value is



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outputted. The new capacitance value that is found is proportional to the level of measured material.16


General capacitor equation between two plates

(1)

C=0.255 k ( AD )

Where C is the capacitance, k is the dielectric constant, A is the area of plates, and D is the distance between plates

Equation (1) can be modified in terms of a gas and liquid

(2)

C=0.225(k gas Agas)

Dgas+

0.225(k liquid A liquid)D liquid

Since distance of electrode and tank won’t move and dielectric of gas and liquid are constant, equation (2) reduces down to

C=k gas Agas+k liquid Aliquid

Capacities that is found is directly proportional to level of liquid16



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Figure 5: General Capacitor16

Figure 6: Capacitive Measurement in Non-Conductive liquid and gas16

A manufacturer that produces capacitive liquid level detectors is GILL. An industrial liquid level sensor that is up to 2 meters long and made of 316 stainless steel, can read 0-10 volts of analogue output. At GILL sensors, all their liquid level sensors are factory calibrated with temperature compensation to offer high precision. With no moving parts liquid level measurement comes out at a high accuracy to ∓2%.15

The capacitive liquid detectors are capable of measuring high and low temperature liquids. The types of liquids it can end up reading can range from hot molten liquid metals to freezing liquid gases.5 Since it contains no moving parts, it is easy to install and thus requires minimal



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maintenance.14 With great advantage though come with some disadvantages. Materials with a

light density under 20 lbf t3 can cause errors due to their low dielectric constants.14 It is not capable

of reading solutions with different compositions. This is because of there being different materials with their own dielectric constants. Because of this the overall dielectric constant ends up changing which can cause a misreading.16

It is already capable of reading electrical signals so no further modifications are necessary. Not only are capacitive liquid level detectors only capable of reading non-conducting materials but they are also capable of reading conducting material and proximity measurements.16 The detectors can take different forms including a double plated cylinder.5

Ultrasonic Level Sensor

The ultrasonic level sensor uses a time-of-flight measurement method. This method includes a sensor which acts as both a transmitter and a receiver. A pulse is first sent off from the transmitting phase toward a liquid. Once the pulse hits the surface of the liquid, an echo is produced that travels back to the sensor. Now the sensor acting as a receiver translates the echo via an electronic device. The echoes received are analyzed on how much time it took for the pulse to the liquid surface and back. This is how the distance from the liquid surface to the sensor is found.28

Equation that governs physics28

d= c∗t2

Where d is the distance of liquid surface to sensor, c is the velocity of sound, and t is the time of flight



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Figure 11: Ultrasonic Level Sensor29

A manufacturer of the ultrasonic level sensor is Coulton. The MonoScan is capable of measuring a range of liquid levels from 0 m to 15 m in a tank vessel. Once installed in a tank, it is capable of self-calibration to different conditions for high precision. In the designated range, it is capable of having an accuracy of 0.25%.30

Since it is electronic, there are no moving parts which means it can measure levels without making physical contact with liquid. It is capable of measuring levels in tanks that contain corrosives, boiling, and hazardous chemicals.29 With great advantage though come with some disadvantages. If there is a layer of heavy foam formed on top of the liquid, the sound waves can get absorbed thus resulting in the liquid level not being measured. If the liquid is in high turbulence, the sensor can end up showing fluctuated readings.31

It is already capable of reading electrical signals so no further modifications are necessary. Ultrasonic level sensors are also capable of measuring two or more immiscible liquid levels in one tank.5 The time-of-flight method not only applies to ultrasonic level sensors but also to microwave sensors. If there is a gas or precipitation that forms above liquid in a tank, a microwave sensor is preferred since the density gradient ends up changing. 28



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Knowing for task 4 that Professor Burrows did not go over any instruments that measure liquid in a vessel, both instruments had to be found by research. There were no special requirements for any of the instruments in this task unlike the past tasks that were accomplished. I only had to find two instruments that can measure liquids in a vessel and I feel that this is a straight forward concept overall.



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References

1Stanford University. http://web.stanford.edu/class/me220/data/lectures/lect04/lect_8.html (accessed Jan 10, 2015).

2ThermCo Products,INC. http://www.thermcoproducts.com/ASTM-Thermometers.html (accessed Jan 12, 2015).

3Boyes, Walt. Instrumentation Reference Book, 3rd ed.; Elsevier, 2003.

4Burrows, Veronica. “Lecture 8: Measurement 2 – temperature.” Jan 4, 2015. PowerPoint Presentation.

5Morris, Alan S. Langari, Reza. Measurement and Instrumentation - Theory and Application; Elsevier, 2012

6HYVAC PRODUCTS, INC. http://www.hyvac.com/Products/Gauges/McLeod_gage_specs_files/Other_McLeod_Gauges.htm (accessed Feb 19, 2015)

7efunda. http://www.efunda.com/designstandards/sensors/mcleod/mcleod_intro.cfm(accessed Feb 19, 2015)

8Sella, Andrea. Royal Society Of Chemistry. http://www.rsc.org/chemistryworld/Issues/2011/September/McLeodsVacuumGuage.asp(accessed Feb 19, 2015).

9AIP Scitation. http://scitation.aip.org/content/aip/journal/rsi/22/3/10.1063/1.1745891 (accessed Mar 3, 2015).

10LaNasa, Paul J. Upp, E. Loy. Fluid Flow Measurement - A Practical Guide to Accurate Flow Measurement; Elsevier, 2014.

11efunda. http://www.efunda.com/designstandards/sensors/flowmeters/flowmeter_tbn.cfm (accessed Feb 19, 2015).

12Liquid Controlshttp://www.lcmeter.com/en/Products/productPages/Turbine.html(accessed Feb 20, 2015).

13Liquid Controls.



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http://www.lcmeter.com/en/Literature/Documents/Overviews/IN100-10%20Turbine%20Overview.pdf(accessed Feb 20, 2015).

14Sakshat Virtual Labs.http://coep.vlab.co.in/?sub=33&brch=91&sim=449&cnt=1(accessed Feb 22, 2015)

15GILL.http://gillsc.com/content/industrial-liquid-level-sensor.html(accessed Feb 23, 2015)

16omega.http://www.omega.com/GREEN/pdf/CAP_LEV_MEAS.pdf(accessed Feb 23, 2015)

17S. K. Likhi. Hydraulics: Laboratory Manual; New Age International, 1995.

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19Jingxian County Xinsheng rubber metal products Co., Ltd.. http://www.xinsheng-hose.com/info/Piezometric-tube-156-1.htm (accessed Feb 24, 2015).

20environmental-expert. http://www.environmental-expert.com/products/bat-piezometer-88755 (accessed Feb 24, 2015).

21GEO-HYDROMECHS (INDIA). http://www.geohydromechsindia.com/porous-tube-piezometers.htm (accessed Feb 24, 2015).

22Kazmer, David O. Plastics Manufacturing Systems Engineering - A Systems Approach; Hanser Publishers, 2009.

23optrics. http://www.optris.com/optris-cs (accessed Mar 1, 2015).

24omega. http://www.omega.com/prodinfo/infraredthermometer.html (accessed Feb 28, 2015).

25FOUNDRY. http://foundrymag.com/testingqc/infrared-pyrometer-thermal-imaging-capabilities (accessed Feb 28, 2015).

26efunda. http://www.efunda.com/designstandards/sensors/flowmeters/flowmeter_ustt.cfm



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(accessed Mar 2, 2015).

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28Kress-Rogers, E. Brimelow, C.J.B.. Instrumentation and Sensors for the Food Industry, 2nd ed.; Woodhead Publishing, 2001.

29COULTON. http://www.coulton.com/beginners_guide_to_ultrasonic_level_transmitters.html (accessed Mar 2, 2015).

30COULTON. http://www.coulton.com/Ultrasonic_Level_Transmitters.html (accessed Mar 2, 2015).

31sensore ONLINE. http://www.sensorsmag.com/sensors/leak-level/the-principles-level-measurement-941 (accessed Mar 2, 2015).

32AZO SENSORS. http://www.azosensors.com/Article.aspx?ArticleID=369 (accessed Mar 2, 2015).

33Sensors Web. http://www.sensorsweb.com/diodes_silicon_bandgap_temperature_sensor (accessed Mar 2, 2015).

34QUALITYDIGEST. http://www.qualitydigest.com/inside/metrology-article/benefits-silicon-based-temperature-sensors.html (accessed Mar 2, 2015).

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36University of Illinois at Urbana-Champaign. http://coecsl.ece.illinois.edu/ge423/sensorprojects/gilliam%20-%20temp%20sensors.pdf (accessed Mar 2, 2015)

37Hughes, Thomas A.. Measurement and Control Basics 4th ed.; ISA, 2007.

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40PCM. http://www.pcm-uk.com/straingauge-whatisastraingauge.html

(accessed Mar 3, 2015).

41HBM. http://www.hbm.com/en/menu/products/strain-gages-accessories/strain-gauges-for-stress-analysis/y-series-universal/ly-linear/ (accessed Mar 3, 2015).



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Discussion

For the 4 tasks given in assignment 2, research was the bulk of these tasks. This paper provides tons of useful information for each instrument. I feel that this paper can definitely be used in real world applications. It can be used to give new interested engineers an idea of what is to be expected if they decide to major in chemical engineering. This work accomplishes all that was given and actually more with all the additional information for each instrument. All tasks follow in an orderly fashion with no unidentified parts appearing.



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Post-Reflection

For this assignment I was more than surprised by how much work went into completing it. It was a good idea to start early, but even then I still had four more instruments to do a couple of days before it was due. How I ended up approaching this assignment was that I would alternate between tasks. This helped in keeping my interest in this work fresh because doing research on the same types of instruments in a row would get very tedious. A weakness that I ended up having was just trying to find the time to do this project. Even though I did not have any lab reports to do during this time period, it was still hard to find time. What I ended up deciding on doing was to start staying up to 2:30 AM on the weekdays. This helped tremendously in getting instruments researched even though I had to lose a lot of sleep out of it. When doing this research I ended up learning lots of cool and interesting information about each instrument. This can definitely help in applying to companies that require some knowledge about the instruments that I researched. Deriving formulas at times required a great deal of my algebra skills when formulas ended up getting bigger and nastier. I feel that this project has taught me a lot of what real chemical engineers go through in their daily lives. This includes scheduling times in the week to work on it, staying up late at nights to accommodate for time, and getting used to a strict deadline. Assignment 2 has taught me a lot and it does not need any additions to it. It has increased my interest in the different types of measuring devices, especially in flow meter devices.


Measuring Instruments Project

Engineering

Transcript of Measuring Instruments Project