艾默生質(zhì)量流量計原理

艾默生質(zhì)量流量計原理第一頁，共41頁。(=

Transparency

2)Note:

TX-2

depicts

a

systembased

on

the

RFT9739.

For

the

same

systemwith

the

RFT9712,

use

TX-144;

for

the

IFT9701,

use

TX-145.Use

TX-2

to

orient

the

class:Point

out

corresponding

components

on

the

PMDs.Don’t

spendalot

of

time

atthis

point

explainingwhat

particular

components

do

orhow

to

operate

them.

Also,

don’t

confuse

things

at

this

point

by

usingmodel

designations.Make

sure

class

understands

the

distinction

between

the

transmitter

interface

(used

to

communicate

with

the

transmitter

but

generally

not

required

fornormal

operation)

and

the

peripheral

interface

(which

is

usually

the

operatinginterface

with

the

flowmeter).議程科里奧利質(zhì)量流量計原理安裝、投用和基本維護Micro

Motion

Confidential第二頁，共P4a1g頁e。2(=

Transparency

2)Note:

TX-2

depicts

a

systembased

on

the

RFT9739.

For

the

same

systemwith

the

RFT9712,

use

TX-144;

for

the

IFT9701,

use

TX-145.Use

TX-2

to

orient

the

class:Point

out

corresponding

components

on

the

PMDs.Don’t

spendalot

of

time

atthis

point

explainingwhat

particular

components

do

orhow

to

operate

them.

Also,

don’t

confuse

things

at

this

point

by

usingmodel

designations.Make

sure

class

understands

the

distinction

between

the

transmitter

interface

(used

to

communicate

with

the

transmitter

but

generally

not

required

fornormal

operation)

and

the

peripheral

interface

(which

is

usually

the

operatinginterface

with

the

flowmeter).流量計系統(tǒng)部件流流量量變變送送器器((RRFFTT99773399))流量傳感器(ELITE

CMF)頻率/脈沖輸出(0-10

kHz)毫安輸出(4-20

mA)后位設(shè)備后位設(shè)備(ALTUS

Model

3300)變送器接口(HC275)Micro

Motion

Confidential第三頁，共P4a1g頁e。3(=

Transparency

9)Other

factors

besides

temperature

and

pressure

come

into

play

when

using

most

volumetric

flow

measurement

technologies.

These

factors

don’taffect

Coriolis.Perhaps

the

best

way

to

get

at

this

is

to

ask

the

question

first:

Is

volumetric

measurement

affected

by

other

factors?If

there’s

no

response,

just

give

the

answer,

as

shown

on

the

transparency.

If

the

audience

has

some

knowledge,

make

aquick

list.

There’s

no

need

todiscuss

flow

regime

or

Reynolds

numbers.One

important

point

is

that

Coriolis

measures

mass

directly.

Until

relatively

recently,

this

technologywasn’t

available.

If

you

wanted

to

measure

massusingavolumetric

method,

how

would

you

do

it?

The

answer

involves

density,

whichleads

to

the

next

topic.Micro

Motion

Confidential第四頁，共P4a1g頁e。4(=

Transparency

8)Perhaps

better

question:

Why

measure

volume?The

volume

of

afluid

(and

its

density)

varies

with

its

temperature

(and

pressure).

What

about

mass?If

you

are

paying

by

the

gallon,

do

you

want

to

buy

the

834

poundsat

200

degrees

or

at

60

degrees?Micro

Motion

Confidential第五頁，共P4a1g頁e。5(=

Transparency

10)Coriolis

density

measurement

is

direct

and

virtuallycontinuous.

Why

is

that

better

than

sampling?Remember

that

density

varies

with

temperature

and

pressure.

What

happens

when

you

remove

material

from

the

process?What

if

your

process

is

inconsistent?

How

often

do

you

need

to

sample

in

order

to

be

able

to

approximate

average

density?It’s

performed

automatically

and

almost

instantaneously,

so

it’s

more

convenient

and

the

information

is

much

more

useful

for

controlling

the

process.Micro

Motion

Confidential第六頁，共P4a1g頁e。6Micro

Motion

Confidential第七頁，共P4a1g頁e。7傳感器操作原理動畫演示Micro

Motion

Confidential第八頁，共P4a1g頁e。8Coriolis

Meters

operate

byvibrating

the

flow

tubes

at

their

natural

frequency.科里奧利流量計–彎管結(jié)構(gòu)Micro

Motion

Confidential第九頁，共P4a1g頁e。9An

RTD

is

attached

to

the

flow

tubes

to

provide

compensation

for

the

change

in

elasticity

of

the

tubes

as

the

temperature

changes.

This

temperaturesignal

is

also

available

as

an

monitoring

or

control

variable.科里奧利流量計–彎管結(jié)構(gòu)Micro

Motion

Confidential第十頁，共P4a1g頁e

1。0科里奧利流量計–彎管工作原理Micro

Motion

Confidential第十一頁，共Pa4g1e頁11?？评飱W利流量計–彎管工作原理Micro

Motion

Confidential第十二頁，共Pa4g1e頁12。Micro

Motion

ConfidentialPage

13科里奧利流量計–彎管工作原理第十三頁，共41頁。Micro

Motion

Confidential第十四頁，共Pa4g1e頁14。Micro

Motion

Confidential第十五頁，共Pa4g1e頁15。變送器怎樣計算質(zhì)量流量流量標定常數(shù)

(

在工廠或現(xiàn)場標定)流量標定常數(shù)，4.5523g/s/us

X

(1-1)usK

flow

=每產(chǎn)生1μs相差所對應的流量(單位為克每秒)零流量偏移，調(diào)零(滿管,

靜止,

等溫)K

zero=傳感器無流量時的相差流量溫度修正，5.13%/100CFTC=溫度變化100C時由于流量管剛性變化而引起的流量百分比誤差質(zhì)量流量計算(由變送器進行)質(zhì)量流量

=

KX

(△t-

Kflow

zero)X(1-(FTC

X

TDegC

))Micro

Motion

Confidential第十六頁，共Pa4g1e頁16。密度工作原理1.當質(zhì)量增加時，系統(tǒng)的諧振頻率就減少。2.

當質(zhì)量減少時，系統(tǒng)的諧振頻率就增加。在高準質(zhì)量流量計中，質(zhì)量和諧振頻率之間的關(guān)系是密度測量的基礎(chǔ)。去理解這個關(guān)系，就認為是彈簧和質(zhì)量系統(tǒng)。Micro

Motion

Confidential第十七頁，共Pa4g1e頁17。密度工作原理Micro

Motion

Confidential第十八頁，共Pa4g1e頁18。Micro

Motion

Confidential第十九頁，共Pa4g1e頁19。密度標定系數(shù)密度標定系數(shù)(在標定時得出)K

1D

1K

2D

2Tc傳感器注入低密度標定介質(zhì)(空氣)時的管道周期低密度標定介質(zhì)的密度傳感器注入高密度標定介質(zhì)(水)時的管道周期高密度標定介質(zhì)的密度溫度變化100C時由于流量管剛性變化而引起的密度百分比誤差Micro

Motion

Confidential第二十頁，共Pa4g1e頁20。密度工作原理Micro

Motion

Confidential第二十一頁，P共ag4e12頁1

。(=

Transparency

19)We

need

to

knowtemperature

to

compensate

for

its

affect

on

the

elasticity

and

rigidity

of

the

metal

flow

tubes,

which

determine

how

the

tubes

respondsspecifically

to

flow

and

density.

We’ll

discuss

that

againlater.The

temperature

indicated

by

the

RTD

also

represents

the

temperature

of

the

process

with

considerable

accuracy.

In

current

Micro

Motionsensordesign,

the

RTDtemperature

is

equivalent

to

a

thermowell

sensor

in

terms

of

indicatingprocess

temperature.Micro

Motion

Confidential第二十二頁，P共ag4e12頁2

。Micro

Motion

Confidential第二十三頁，P共ag4e12頁3

。Micro

Motion

Confidential第二十四頁，P共ag4e12頁4

。標準安裝方式適當?shù)闹亓χ谓Y(jié)構(gòu)適當?shù)姆ㄌm連接結(jié)構(gòu)無需直管段Micro

Motion

Confidential第二十五頁，P共ag4e12頁5

。質(zhì)量流量計的安裝傳感器的安裝管線：上下游都不需要有直管段；調(diào)節(jié)閥要裝到流量計的下游；在傳感器的兩側(cè)安裝截止閥；在傳感器的兩側(cè)管段設(shè)置穩(wěn)固的支撐；為便于調(diào)試及維護，考慮安裝旁路。在測量易汽化介質(zhì)時，傳感器后建議工藝管與流量計保持同口徑一段距離，以及傳感器后安裝閥門可以用以調(diào)節(jié)適當?shù)谋硥?，防止汽化或氣穴發(fā)生。Micro

Motion

Confidential第二十六頁，P共ag4e12頁6

。質(zhì)量流量計的安裝變送器的安裝位置要易于數(shù)據(jù)查看和維護。便于過程數(shù)據(jù)查看方便儀表組態(tài)與檢查專用的儀表電源，保證儀表運行穩(wěn)定，避免硬件損壞Micro

Motion

Confidential第二十七頁，P共ag4e12頁7

。施工注意問題如為新建管線，在吹掃過程結(jié)束后再安裝傳感器；在管線上進行焊接作業(yè)時，要取下傳感器；在安裝大口徑傳感器時，不要將支撐物支撐在傳感器外殼上。Micro

Motion

Confidential第二十八頁，P共ag4e12頁8

。投表準備工作傳感器、變送器接線檢查及設(shè)備上電。檢查儀表參數(shù)。儀表基本組態(tài)。儀表組態(tài)數(shù)據(jù)記錄。注：上述組態(tài)項目可通過變送器的顯示器、手操器或組態(tài)軟件完成。Micro

Motion

Confidential第二十九頁，P共ag4e12頁9

。投表準備工作傳感器、變送器接線檢查及設(shè)備上電。專用信號電纜電源接線輸出接線Micro

Motion

Confidential第三十頁，共Pa4g1e頁30。投表準備工作儀表參數(shù)檢查–傳感器特性化參數(shù)、儀表系數(shù)等與設(shè)備銘牌、校準證書是否一致。Micro

Motion

Confidential第三十一頁，P共ag4e13頁1

。投表準備工作儀表基本組態(tài)組態(tài)測量單位，根據(jù)需要選擇過程變量的單位，包括質(zhì)量流量、體積流量、溫度、密度等；組態(tài)毫安輸出或脈沖輸出的過程變量與量程；組態(tài)過程變量阻尼，包括流量，密度，溫度；組態(tài)流向；回路測試（數(shù)據(jù)遠傳）；儀表調(diào)零（并不總是需要）。Micro

Motion

Confidential第三十二頁，P共ag4e13頁2

。Qm

=

FCF

*(△t

-

△t0)Qm：質(zhì)量流量FCF：Flow

Cal

Factor流量標定系數(shù)△t：由真實質(zhì)量流量引起的相位差△t0

：FlowSignal

Offset

AtZeroFlow(Zerooffset)零流量點的流量信號偏移量零點影響Micro

Motion

Confidential第三十三頁，P共ag4e13頁3

。零點影響不正確的零點會帶來什么?改變了在Y軸的截距斜率(儀表系數(shù))沒有變化ATrue

Mass

Flow

RateIndicated

Mass

Flow

RateA”A’%

Mass

Flow

Error

=(A”

–

A’)A’X

100

%MFMicro

Motion

Confidential第三十四頁，P共ag4e13頁4

。零點影響零點誤差(A’’-A’)流量

(A’)%誤差