Ins. Flow OTI.ppt

8/17/2019 Ins. Flow OTI.ppt

1/65

Level 1 - Flow

1

Level 1

Fundamental TrainingFundamental Training


2/65

Level 1 - Flow

2

Topics: Slide No:

• Why measure flow? 3 - 4

• Flow terminology 5 - !

• Flowmeter selection " - #4

• $% flowmeters #5 - 4&

• 'elocity flowmeters 4( - 55

• )ass flowmeters 5& - &

• $isplacement meters

• *osemount flow products summary &3

• +,ercise &4 - &5

ontentsontents


3/65

Level 1 - Flow

3

Safety

• Uncontrolled flow rates may cause

– temperature & pressure to reach dangerously high levels – turbines & other machinery to overspeed

– tanks to spill

ustody Transfer

• the measurement of fluid passing from a supplier to a customer

–cash register o the system

– e!ample a local gas station measures how much gas being pumped into the

vehicle or billing

– re"uires high measurement accuracy

%roduct .ntegrity

• ensuring right amount of blended materials in for example processed food &

gasoline

Why measure flow?Why measure flow?5 Common Reasons5 Common Reasons


4/65

Level 1 - Flow

#

+fficiency .ndication• to determine efficiency of process by – measuring the amount o each input that has gone into the

product

– comparing the above measurement to the amount o product

produced%rocess 'aria/le ontrol

• Flow rate is measured & controlled during energy transfer

application, for example

– heat e!changer

$ fluid temperature controlled by varying the flow rate ofsteam

Why measure flow?Why measure flow?5 Common Reasons5 Common Reasons


5/65

Level 1 - Flow

%

Flow terminologyFlow terminologyFlow Control LoopFlow Control Loop

.0% F.

TTFT

• Flow 1oop .ssues:

– May be a ery Fast !rocess

$ 'oise( in )easurement *ignal

⇒ May Re"uire Filtering $ )ay +e"uire Fast-+esponding ,"uipment

– #ypically Re"uires #emperature Compensation


6/65

Level 1 - Flow

• $ensity: ρ rho2 m0' mass0olume

– )ass per unit volume at given operating conditions. – /ommon units0 kgm3 or lbt3

– ensity o a li"uid varies with temperature

– ensity o a gas varies with temperature and pressure

Flow terminologyFlow terminologyFluid !ropertiesFluid !roperties

1iuids 6ases

↑ emperature 4 ↓ ensity ↑ emperature 4 ↓ ensity

↓ emperature 4 ↑ ensity ↓ emperature 4 ↑ ensity

↑ 5ressure 4 'o change ↑ 5ressure 4 ↑ ensity↓ 5ressure 4 'o change ↓ 5ressure 4 ↓ ensity


7/65Level 1 - Flow

6

For 1iuids7

• $pecific %raity

For 6ases7

• $pecific %raity

Density of liquid at process temperature

Density of water at 15.6°C

Molecular Weight of gas

Molecular Weight of air



8/65Level 1 - Flow

7

• %as Compressibility Factor' ()factor ()factor

– 8sed to correct gas e"uations or real-gas eects. 9ccounts or the deviation rom the ideal( situation.

$ For an ideal gas 8 and %'n*T9.deal 6as 1aw2

$ The True 6as 1aw: %'8n*T

$ 8 ; n an /e found in engineering ta/les

$ * is dependant on units chosen for %7 T ; '

PV = nRT

Absolute pressure

Volume

Molecular weight

Universal gas constant

9bsolute temperature



9/65Level 1 - Flow

:

• 'iscosity

– Measure of a fluid*s tendency to resist a shearing force, or to resist flow

$ 9 greater orce is re"uired to shear high viscosity luids than low viscosity luids ;viscosity 4 shear stressshear rate


10/65Level 1 - Flow

1?

• Fluid Type

– Clean Fluid$ 9 luid that is ree rom solid particles> e.g. clean water.

– +irty Fluid

$ 9 luid containing solid particles> e.g. muddy water.

– $lurry

$ 9 li"uid with a suspension o ine solids> e.g. pulp and paper> or oatmeal.

– $team

$ @ater vapour

– %as

$ 'atural gas



11/65Level 1 - Flow

11

Laminar Flow #urbulent Flow

Transition Flow


• Flow %rofile

Aigher velocity in the middle

Lower velocity at the edge

Lower velocity at the edge

5ipe @all


12/65Level 1 - Flow

12

< #


13/65Level 1 - Flow

13

Flow conditions= 'elocity g0m

Temperature #5@

'iscosity


14/65Level 1 - Flow

1#

• %ressure ; Temperature changes inside process pipe determines which state

the steam is in – *aturated steam ;all vapor<

$ Steam e,actly at its saturation point 9S%2

⇒temperature ( pressure at which li)uid turns to vapor "as pressure increases, saturationtemperature increases'

– *uperheated steam

$ Steam when pressure drop /elow S%

$ Steam when temperature rise a/oe S%

⇒e$g$ at *+0 psia, saturation temperature for water is -.$⇒/team at *+0 psia ( -. includes +2-. of super heat

– Cuality steam ; mi!ture o water li"uid & vapor<

$ ondensed steam when pressure rise a/oe S%

$ ondensed steam when temperature drop /elow S%



15/65Level 1 - Flow

1%

• Te,ture of inner walls

– smooth wall slightly increase fluid elocity

– rough wall slightly decrease fluid elocity

• .nside diameter

– eg, doubling the diameter increase flow rate byas much as - times

$ =ol. low rate;Cv< 4 /ross-section area D =elocity

4 π2# D =elocity

4 2;π# ! =elocity<

Flow terminologyFlow terminology!ipe %eometry & Conditions!ipe %eometry & Conditions

Q v = ( 2 2 D) 2 * ( π/4 x Velocity)

Qv = 4 4 (D 2 * ( π/4 x Velocity))


16/65Level 1 - Flow

1

• Flow %rofile $istur/ance

– factors that cause flow profile to become irregular $ symmetrical proile

⇒caused /y reducers or e,panders pipe sections⇒eliminated /y inserting appropriate length of straight pipes

$ asymmetrical proile

⇒caused /y el/ows7 ales and tees⇒eliminated /y inserting appropriate length of straight pipes

$ swirl

⇒caused /y pumps7 compressors7 or two pipe el/ows in differentplanes

⇒eliminated /y inserting flow conditioners

Flow terminologyFlow terminology!ipe %eometry & Conditions!ipe %eometry & Conditions


17/65Level 1 - Flow

16

• )etric 8nit- m3 0s

• Ethers

⇒ $tdCuft.s 3 /tandard .ubic feet per second ⇒ $tdCuft.min 3 /tandard .ubic feet per minute

⇒ $tdCuft.h 3 /tandard .ubic feet per hour ⇒ $tdCuft.d 3 /tandard .ubic feet per day ⇒ $tdCum.h 3 /tandard .ubic meter per hour ⇒ $tdCum.d 3 /tandard .ubic meter per day

⇒ /mlCum.h 3 4ormal .ubic meter per hour ⇒ /mlCum.d 3 4ormal .ubic meter per day

'olumetric Flow *ate

t! " re#erence to $4%&'& si tm% at & !e+%F ,ml " re#erence to $-$%.2 tm% t - !e+%0

Flow terminologyFlow terminology0ngineering Units0ngineering Units


18/65Level 1 - Flow

17

)ass Flow *ate

• )etric 8nit- >g0s

• Ethers

⇒ lbs.sec 3 Pounds per second ⇒ lbs.min 3 Pounds per minute

⇒ lbs.hour 3 Pounds per hour ⇒ lbs.day 3 Pounds per day ⇒ gram.sec 3 grams per second ⇒ grams.min 3 grams per minute

⇒ grams.hour 3 grams per hour ⇒ 1g.min 3 %ilograms per minute⇒ 1g.hour 3 %ilogram per hour

Flow terminologyFlow terminology0ngineering Units0ngineering Units


19/65Level 1 - Flow

1:

Flowmeter selectionFlowmeter selection$pecification$pecification

• Accuracy

– 2 of rate$ uncertainty o low proportional to low rate

– 2 of full scale

$ uncertainty o low remains constant

+ate o Flow o +ate 9ccuracy 8ncertainty +ange

100 gpm 56 of 100 gpm 7310 gpm

+0 gpm 56 of +0 gpm 873+1 gpm0 gpm 56 of 0 gpm 17$230$8 gpm

+ate o Flow o +ate 9ccuracy 8ncertainty +ange

100 gpm 56 of 100 gpm 7310 gpm

+0 gpm 56 of +0 gpm 873+1 gpm

0 gpm 56 of 0 gpm 17$230$8 gpm

Fl l i


20/65

Level 1 - Flow

2?

Flowmeter selectionFlowmeter selection$pecification$pecification

• *angea/ility 9Turndown2

– Meter maximum

$ ma!imum low rate that a lowmeter is capable o reading

⇒commonly used for magnetic7 orte, and oriolis meters

– 3pplication maximum

$ ma!imum lowrate that occurs in the process low o a

particular application⇒commonly used for orifice plates7 flow noBBles7 and enturi

tu/es

• *epeata/ility

– the ability of a flowmeter to produce the same

measurement each time it measures a flow

Fl t l ti


21/65

Level 1 - Flow

21

Flow Technologies

Mass Volumetric Head

VelocityMeter

PositiveDisplacement

Meter

Coriolis Meter

Thermal Meter

DP FlowMeter

TargetMeter

Annubar

Orifice

Venturi

Nozzle

Elbow Taps

Magnetic

Vortex

Ultrasonic

Turbine

Oval

Nutating disc

Gear

Gerotor

Flowmeter selectionFlowmeter selectionClasses of FlowmetersClasses of Flowmeters

Fl l iFl t l ti


22/65

Level 1 - Flow

22

.• $isplacement )eters – measure olume flow rate 4 directly by

repeatedly trapping a sample of the fluid

$ total volume 4 sample volume D number o samples

⇒Cigh pressure loss• Cead )eters 9$% Flow )eters2

– measures fluid flow indirectly by creating &

measuring a differential pressure by means of a

restriction to the fluid flow


Fl t l tiFl t l ti


23/65

Level 1 - Flow

23

A reliable flow measurement is dependent upon the correct

measurement of 3 and $

• 'elocity )eters

– FL6 is measured inferentially by measuring0LC7#8 through a 1nown 3R03

$ @ith this indirect method> the low measured is the

volume low rate> D. *tated in its simplest term

$ Q V = * v where⇒ 90 cross3sectional area of the pipe

⇒v0 fluid velocity

1 m./s = m2 * m/s


Fl t l tiFl t l ti


24/65

Level 1 - Flow

2#

• )ass )eters

– 7nfer the mass flow rate ia the e"uation9

1 Qm = Qv * ρ where>⇒Cm0 the mass flow rate

⇒Cv 0 the volume flow rate

⇒ρ 0 fluid density 1 +/s = m./s * +%m.

– Consist of : deices9

$ Ene device will measure luid velocity

$ he other device will measure luid density


$% fl t$% fl t


25/65

Level 1 - Flow

2%

Flow *estriction in 1ine cause a differential %ressure

Line 5ressure

Eriice 5late;5rimary ,lement<

QV= K DP

onstant

$% flowmeter $% flowmeter +! Flow 0"uation+! Flow 0"uation

H.P. L.P.

$% fl t$% fl t


26/65

Level 1 - Flow

2

FE

FT

FIC

Outputs represent true flow only under specified conditions.

Using “constants” in flow equations assumes a static flow

environment. For DP flowmeter output to represent true flowtrue flow t!e following

fluid properties must "e constant#

Fluid density

Fluid viscosity

D3 volumetric#low

QV= K DP%rimary

+lement

%ressure

Transmitter

Flow ontroller

ontrol

'ale


$% fl t$% fl t


27/65

Level 1 - Flow

26

$ For arying fluid densityfluid density and iscosityiscosity

– Compensation is re"uired to represent #RU0 flow

QM= K DP!P"T# Partial

CompensationTakes care of

Density only

Mass Flow, QM = Volumetri !low " Densit#= m$/s " %&/m$

= %&/s


$% fl t$% flowmeter


28/65

Level 1 - Flow

27

Traditionally way of partially compensated $% mass$% mass

flowflow has /een accomplished using a Esystem

F,

F

5 F/ FB/%ressure

Transmitter

9A%2

%ressure

Transmitter

9$%2

Temperature

Transmitter G

Sensor

Flow omputer

Flow

ontroller

ontrol

'ale

%rimary+lement

QM= K DP!P"T#


$% fl t$% flowmeter


29/65

Level 1 - Flow

2:

• 3


30/65

Level 1 - Flow

3?

/ d 9ctualHlow

3heoreticalHlow

• C d is a correction factor to the theoretical e"uation

,"uations or calculating /d are derived rom e!perimental data.

/d is a unction o beta ratio and +eynolds number> and is dierent

or each primary element.

$ischarge oefficient 9d2

• +ensity is /# constant for gasesI 1 1I 1 >>>β k ∆5 5 1 $or %i&uids'

> is the isentropic e,ponent7 a

property of gases:k

/ p

/ v

6as +,pansion Factor 9I2

= ( )

"9eta ratio # restriction diam$ & pipe diam$'


QM= K DP!P"T#

$% flowmeter$% flowmeter


31/65

Level 1 - Flow

31

Cd

* D


32/65

Level 1 - Flow

32

? % 1?#

1 1?%

1.% 1?%

2 1?%

2.% 1?%

3 1?%

3.% 1?%

# 1?%

#.% 1?%

% 1?%

?.%:

?.

?.1

?.2

?.3

?.#

?.%

?.

Keta (5

Keta &Keta 5

Keta 4

Keta #

Lrifice %late $ischarge oefficients

%ipe *eynolds Num/er

2 i s c h a r g e / o e i c i e n t

( 4” !"#g$ T"%s &

$ischarge oefficient s *$ ; β

ri#ice Diam% / 3ie Diam% = 5eta !/D = β

Jeta =alues are

almost constant




33/65

Level 1 - Flow

33

? 2? #? ? 7? 1?? 12? 1#? 1? 17? 2?? 22? 2#? 2??.7%

?.:

?.:%

1


34/65

Level 1 - Flow

3#

Secondary - measures the dierential pressure.

S)CONDAR*

Using well3established conversion

coefficients which depends on the type

of head meter used and the diameter of

the pipe, a measurement of the

differential pressure may be translated

into a volume rate$

$% Flow )eters consist of two main components:

+R-AR*

%rimary - placed in the pipe to restrict the low.

Eriice> =enturi> noGGle> 5itot-static tube> elbow>and wedge.

$% flowmeter $% flowmeter ComponentsComponents



35/65

Level 1 - Flow

3%

• Simplest and least e,pensie

• onstrict fluid flow to produce diff pressure across the plate

• %roduce high pressure upstream and low pressure

downstream

• Flow proportional to suare of the flow elocity

• 6reater oerall pressure loss compared to other primary

deices• ost does not increase significantly with pipe siBe 9adantage2

$% flowmeter $% flowmeter rifice !laterifice !late



36/65

Level 1 - Flow

3

• 6radually narrows the diameter of pipe

• *esultant drop in pressure is measured• %ressure recoers at the e,panding section of the meter

• For low pressure drop and high accuracy reading applications

• Widely used in large diameter pipes

$% flowmeter $% flowmeter enturi #ubeenturi #ube

:igh Pressure /ide ;ow Pressure /ide

/ross section

9rea 92

/ross

section

9rea 91 Flow

51 52

C ;9ctual< 4 / ! 91 ! 92 2 ! ; 51 -52 <

; 912 - 92

2 < ρ!



37/65

Level 1 - Flow

36

• Cigh elocity flow meter

• +lliptical restriction of flow at noBBle opening• No outlet area for pressure recoery

• For application where tur/ulence is high 9*e M 5


38/65

Level 1 - Flow

37

P V

g

P f

f

f

c

f

f

% %

&

&

& ρ ρ + =

P P f f % &

V f

f

%

ρ

=ernoulli*s energy balance for an

incompressible, non)iscous fluid'

Bn order to measure accurate low rate> a pitot traverse is re"uired.

• Stagnation %ressure Sensing - measures a point elocity

( )V g P P

f %

c f f

f

& %&= − ρ

T$$("! +#( V$!(

$% flowmeter $% flowmeter !itot #ube!itot #ube



39/65

Level 1 - Flow

3:

Fluid Flow

Low ;*tatic< 5ressure apAigh ;Bmpact< 5ressure ap

*tatic pressure portAigh pressure port

$% flowmeter $% flowmeter

!itot #ube!itot #ube

• Lne-point elocity measurement

– accuracy affected by changes in velocity profile

– tube must be moved bac% ( forth in the flow

stream for average measurement



40/65

Level 1 - Flow

#?

Aigh 5ressure ap Low 5ressure ap

/ross section

o 9nnubar

Jlunt

Front

*harp ,dge

Jlunt

+ear A.5. L.5.

Fluid Flow

$% flowmeter $% flowmeter 3eraging !itot #ube >3nnubar? 3eraging !itot #ube >3nnubar?

• .nclude seeral measurement ports oer the entire

diameter of the pipeline

– more accurate flow measurement than the regular

pitot tube

$% Flowmeter$% Flowmeter


41/65

Level 1 - Flow

#1

• Adantages:

– /an be inserted through a small opening.

– /an sample the velocity at many points.

– Low pressure drop> non-obstrusive.

• $isadantages:

– 5itot traverse re"uires a technician> and is time-consuming.

– 5itot tube is ragile ;not suited or industrial app.<

– 5 signal is low.

– 9ccuracy depends on the velocity proile.

– ,asily plugged by oreign material in the luid

$% Flowmeter $% Flowmeter !itot #ube!itot #ube



42/65

Level 1 - Flow

#2

$% flowmeter $% flowmeter 6edge Flow 0lement 6edge Flow 0lement

• inserted in the process pipe

• forms a wedged o/struction on the inner wall ofthe pipe

• usually used with remote seals for measuring

– dirty fluids, slurries ( fluids at high viscosity "low

? ' that tends to build up or clog orifice plates



43/65

Level 1 - Flow

#3

$% flowmeter $% flowmeter )Cone)Cone

• high accuracy

• normally la/-cali/rated• wor> eually well with short and long straight pipes

• for customers who hae limited room for straightpiping reuirements

• can /e used with some dirty fluids

Cead )eterCead )eter


44/65

Level 1 - Flow

##

Cead )eter Cead )eter Rotameter Rotameter

• 'aria/le-area flowmeters

–loat inside the tapered tube rises in response to luid low rate

– pressure is higher at the bottom than the top o the tapered tube

– loat rests where the dp between upper & lower suraces o the

loat balances the weight o the loat

– lowrate read direct rom scale or electronically

• commonly used for indication only



45/65

Level 1 - Flow

#%

Cead )eter Cead )eter #arget Meter #arget Meter

• A disc is centered in the pipewith surface positioned at rightangle to the fluid flow

• Force of the fluid acting againstthe target directly measures thefluid flow rate

• *euires no e,ternalconnections7 seals or purgesystems

• Jseful for dirty or corrosiefluids



46/65

Level 1 - Flow

#

Adantages:

• Low cost

• ,asily installed andor

replaced

•'o moving parts

• *uitable or most gases

or li"uids

• 9vailable in a wide

range o siGes andmodels

$isadantages:

• *"uare-root headlow

relationship

• Aigh permanent

pressure loss

• Low accuracy

• Flow rage normal #01

• 9ccuracy aected by

wear andor damage othe low primary element

especially with corrosive

luids.

Cead )eter Cead )eter #arget Meter #arget Meter

'elocity )eter'elocity )eter


47/65

Level 1 - Flow

#6

3s the conductie process li"uid moes through the field with

aerage elocity , the electrodes sense the induced oltage

• FaradayOs 1aw of electromagnetic

induction• A oltage will /e induced in a

conductor moing through a

magnetic field

• + >K$'

– 0 @ magnitude of induced voltage

– @ velocity of the conductor

– + @ width of the conductor

– = @ strength of the magnetic field

– % # proportionality constant

'elocity )eter 'elocity )eter Magnetic Flowmeter Magnetic Flowmeter

Conductie!rocessMedium

;ining

@ield .oils

/ensing

>lectrodes

// ube

@lange

Magnetic Field A=B >Constant $trength?

B>C

B>C

Variable @low ?ate"@eet Per /econd'

BC

BVC



48/65

Level 1 - Flow

#7

Adantages:

• Ebstructionless low

• 8naected by viscosity>

pressure> temperature and

density

• Kood accuracy• 'o + constraints

• *uitable or slurries and

corrosive> nonlubricating> or

abrasive li"uids

• @ide rangeability ;3?01<

$isadantages:

• Li"uid must be

electrically conductive

• 'ot suitable or gases

• /an be e!pensive>particularly in small

siGes

• )ust be installed so that

the meter is always ull

'elocity )eter 'elocity )eter Magnetic Flowmeter Magnetic Flowmeter



49/65

Level 1 - Flow

#:

3n alternating oltage is produced as each blades cuts the

magnetic lines of flux 0ach pulse represents a discrete olume

of li"uid

• onsist of multi-/lade rotorssupported /y /earings and

enclosed in a pipe section

perpendicular to fluid flow

• Fluid flow dries the rotor

• *otor elocity is proportional tooerall olume flow rate

• )agnetic lines of flu, created /y a

magnetic coil outside the meter

'elocity )eter 'elocity )eter #urbine Meter #urbine Meter

FLE@?otor 9lades

Pic%up Probe



50/65

Level 1 - Flow

%?

Adantages:• Aigh accuracy

• +angeability 1?01

• =ery good repeatability

• Low pressure drops

• /an be used on high

viscosity luids ;but with

lower turndowns<

$isadantages:• )oving parts subect to wear

• /an be damaged by

overspeeding

• Aigh temperature>overspeeding> corrosion>

abrasion and pressure transient

can shorten bearing lie

• +ather e!pensive• Filtration re"uired in dirty luids

'elocity )eter y#urbine Meter #urbine Meter



51/65

Level 1 - Flow

%1

'elocity )eter yortex Flowmeter ortex Flowmeter

*hedder Jar

=ortices

FLE@

Force on$ensor

$ensor

!ioting 3xis

$hedder =ar

ortex$hedderForce

@;ortex

shedding?

– As fluid pass a /luff /ody7 itseparates and generates small

eddies0ortices that are shed

alternately along and /ehind

each side of the /luff /ody

– This ortices cause areas offluctuating pressure that are

detected /y a sensor

– The freuency of orte,

generation is directly

proportional to fluid elocity

'elocity )eter 'elocity )eter


52/65

Level 1 - Flow

%2

Adantages:

• Kood accuracy

• 8sually wide low range

• 8sed with li"uids> gases

and steam

• )inimal maintenance ;no

moving parts<

• Kood linearity over the

working range

$isadantages:

• 'ot suitable or abrasive or

dirty luids

• *traight upstream pipe

re"uired e"ual to 3? times

pipe diameter or longer

• Limited by low velocity ;+

M 1?>???<

yyortex Flowmeter ortex Flowmeter



53/65

Level 1 - Flow

%3

yyUltrasonic FlowmetersUltrasonic Flowmeters

• uses sound waes to determine flow rates of fluids

– #ransit)#ime Method

$ 2 pieGoelectric transducers mounted opposing> to ocus

sound waves between them at #%N angle to the direction o

low within a pipe. Bn a simultaneous measurement in the

opposite direction to luid low> a value ;determined

electronically< is linearly proportional to the low rate.

+eceiver

ransmitter

F1LW

8pstream ransducer

ownstream ransducer



54/65

Level 1 - Flow

%#


• uses sound waes to determine flow rates of fluids

– +oppler 0ffect Method

$ Ene o the 2 transducer mounted in the same case on oneside o the pipe transmits sound waves ;constantre"uency< into the luid. *olids or bubbles within the luidrelect the sound back to the receiver element. Fre"uencydierence is directly proportional to the low velocity in the

pipe.



55/65

Level 1 - Flow

%%

Adantages:

• 'on-intrusive>

obstructionless

• @ide rangeability ;1?01<

• ,asy to install ;especially

or clamp-on version<

• /ost virtually

independent o pipe siGe

• he low measurement is

bi-directional

$isadantages:

• )a!imum temperature 1%?N/

• 5articular luid conditions are

re"uired ;EF-type0 clean

li"uidsO oppler-type0 particles

or impurities in the stream<

• 'ot very high accuracy ;about

P2<

• oppler lowmeter clamp-on

type re"uires a pipe ohomogeneous material

;cement or ibreglass linings

must be avoided<


)ass )eter )ass )eter


56/65

Level 1 - Flow

%

• Lperating %rinciple

– Uses a obsructionless U)shaped tube as a sensor – 3pplies /ewton*s :nd Law of Motion to determine flow rate

– Force mass , acceleration

– #he flow tube ibrates at its natural fre"uency by an

electromagnetic drie system

Coriolis Meter Coriolis Meter



57/65

Level 1 - Flow

%6

• oriolis +ffect

– Fluid flowing through the upward moing tube, pushesdownward against the tube

– Fluid flowing out through the downward moing tube,

pushes upward against the tube

– #he combination of upward and downward resistie forces

causes the sensor tube to twist >coriolis effect?




58/65

Level 1 - Flow

%7Coriolis Meter Coriolis Meter

• Signal Transmission

– #he amount the tube twist is proportional to the mass flowrate of the fluid flowing through it

– 0lectromagnetic sensors located at each side of the tubemeasures the respectie elocity of the ibrating tube atthese points

– #he sensor sends this information to the transmitter whichgies an output signal directly proportional to mass flowrate



59/65

Level 1 - Flow

%:

Adantages:

• Aigh accuracy0 P?.2%

• +elatively low pressure

drops

• *uitable or li"uid andgas low

• ,asy to install

• Flow range ;1?01<

$isadantages:• ,!pensive

• )ounting is critical ;no

vibration<

• Aeat-tracing is re"uiredin some applications




60/65

Level 1 - Flow

?

• Wor>s on the principle of heat transfer /y the fluid flow

– Made up o ; elements arranged along the direction of motion

$ high accurate temperature sensor at upstream

$ an electrical heater in between

$ high accurate temperature sensor at downstream

– #he difference between the two temperature readings is

proportional to the mass flow rate >if the thermal properties ofthe fluid being metered are constant and 1nown?

#hermal Meter #hermal Meter



61/65

Level 1 - Flow

1

Adantages:

• 'o moving parts• *uitable or large siGe

pipe ;insertion type<

• Kood rangeability ;%?01<

• 9ccuracy0 P1 F*• Low permanent pressure

losses

$isadantages:

• )eter sensitive to luid heatconductivity> viscosity> and

speciic heat

• )ostly gas service ;only rare

li"uid service<• *peciic heat o the luid

must be known and constant

i.e. the gas must have a

constant composition

• 5roper operation re"uires no

heat losses due to

conductive e!changes

though the pipe walls

#hermal Meter #hermal Meter

$isplacement flowmeter $isplacement flowmeter


62/65

Level 1 - Flow

2

• An e,ample of positie displacement meter

– #wo meshing oal gears rotate as fluid flows through them – %ears trap a 1nown "uantity of fluid as they rotate

– 0ach complete reolution of both the gears @ - amount of

fluid that fills the space between the gear and the meter

body

– olumetric flow rate is directly proportional to the rotational

elocity of the gears

al %ear Meter al %ear Meter

*osemount flow products*osemount flow products


63/65

Level 1 - Flow

3

Meter

DP'Orifice

()'Orifice

()'*nnu"ar

(agmeter

)orte+

,oriolis

-ur"ine

Fluids

Liquidassteam

Liquidassteam

Liquidassteam

,onductive Fluids

Liquidassteam

*ll

Liquidassteam

Dirty

Fluids

/o

/o

0ome

1es

0ome

1es

/o

iscosity

Low2(edium

Low2(edium

Low

*ny

Low2(edium

*ny

Low2(edium

!ipe

"i#e

3.4 2 53in

3.4 2 53in

3.4 2 6&7in

3.& 2 89in

3.4 2 :in

3.4 2 9in

3.4 2 &5in

Ma$imum

!ressure

9333psig

9333psig

9333psig

%533psig

%533psig

5333psig

9333psig

Ma$imum

%emp.

%64;,

&33;,

&33;,

!ressure

&oss

(edium2Hig!

(edium2Hig!

Low

)ery Low

Low

Hig!<

Hig!

$ummary #able$ummary #able

+,ercise+,ercise


64/65

Level 1 - Flow

#+,ercise+,ercise

1. @hich o the ollowing would generally provide the best turndown Q

;9< 5 - Eriice 5late ;/< )agnetic Flowmeter

;J< =.9.)eter ;< urbine )eter

Which of the following directly measures mass flow rate, and which

volume flow rate$ !ndicate BMC or BVC 2. )agnetic Flowmeter R S

3. =orte! )eter R S

#. /oriolis )eter R S

%. 'on-compensated 5 Flowmeter R S

. Fully-compensated 5 Flowmeter R S

+,ercise+,ercise


65/65

%

6. he ollowing lowmeters all create some pressure loss. 'umber

them in order> beginning with that which create the least loss.;9< =enturi tube R S

;J< 5ositive displacement meter R S

;/< )agnetic lowmeter R S

;< =orte! )eter R S;,< 9nnubar R S

;F< Eriice plate R S

+,ercise+,ercise

Ins. Flow OTI.ppt

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