41-艾默生质量流量计原理

1.高准质量流量计客户培训质量流量计工作原理和安装、投用、基本维护Flow

Application

Team第一页，共四十一页。(=

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

oftime

at

this

point

explaining

what

particular

components

do

orhow

to

operate

them.

Also,

don’t

confuse

things

at

this

point

byusing

modeldesignations.Make

sure

class

understands

the

distinction

between

the

transmitter

interface

(used

to

communicate

with

the

transmitter

but

generally

not

required

for

normaloperation)

and

the

peripheral

interface

(which

is

usually

the

operatinginterface

with

the

flowmeter).议程科里奥利质量流量计原理安装、投用和基本维护Micro

Motion

Confidential第二页，共四P十ag一e页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

oftime

at

this

point

explaining

what

particular

components

do

orhow

to

operate

them.

Also,

don’t

confuse

things

at

this

point

byusing

modeldesignations.Make

sure

class

understands

the

distinction

between

the

transmitter

interface

(used

to

communicate

with

the

transmitter

but

generally

not

required

for

normaloperation)

and

the

peripheral

interface

(which

is

usually

the

operatinginterface

with

the

flowmeter).流量计系统部件流流量量变变送送器器((RRFFTT99773399))流量传感器

(ELITE

CMF)频率/脉冲输出(0-10

kHz)毫安输出(4-20

mA)后位设备后位设备(ALTUS

Model

3300)变送器接口(HC275)Micro

Motion

Confidential第三页，共四P十ag一e页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

to

discussflow

regime

or

Reynolds

numbers.One

important

point

is

that

Coriolis

measures

mass

directly.

Until

relativelyrecently,

this

technologywasn’t

available.

If

you

wanted

to

measure

mass

using

avolumetric

method,

how

would

you

do

it?

The

answer

involves

density,

which

leads

to

the

next

topic.Micro

Motion

Confidential第四页，共四P十ag一e页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第五页，共四P十ag一e页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第六页，共四P十ag一e页6

。Micro

Motion

Confidential第七页，共四P十ag一e页7

。传感器操作原理动画演示Micro

Motion

Confidential第八页，共四P十ag一e页8

。Coriolis

Meters

operate

byvibrating

the

flow

tubes

at

their

natural

frequency.科里奥利流量计–弯管结构Micro

Motion

Confidential第九页，共四P十ag一e页9

。An

RTD

is

attached

to

the

flow

tubes

to

provide

compensation

for

the

change

in

elasticity

of

the

tubes

as

the

temperature

changes.

This

temperature

signal

isalso

available

as

an

monitoring

or

control

variable.科里奥利流量计–弯管结构Micro

Motion

Confidential第十页，共四P十ag一e

1页0。科里奥利流量计–弯管工作原理Micro

Motion

Confidential第十一页，共四Pa十ge一11页。科里奥利流量计–弯管工作原理Micro

Motion

Confidential第十二页，共四Pa十ge一12页。Micro

Motion

ConfidentialPage

13科里奥利流量计–弯管工作原理第十三页，共四十一页。Micro

Motion

Confidential第十四页，共四Pa十ge一14页。Micro

Motion

Confidential第十五页，共四Pa十ge一15页。Micro

Motion

Confidential第十六页，共四Pa十ge一16页。变送器怎样计算质量流量流量标定常数

(

在工厂或现场标定)流量标定常数，4.5523g/s/us

X

(1-1)usKflow

=每产生1

μs

相差所对应的流量(单位为克每秒)零流量偏移，调零(满管,静止,等温)K

zero

=

传感器无流量时的相差流量温度修正，5.13%/100CFTC

=

温度变化100C时由于流量管刚性变化而引起的流量百分比误差质量流量计算

(由变送器进行)质量流量

=

KX

(△t-

Kflow

zero)X(1-(FTC

X

TDegC))Micro

Motion

Confidential第十七页，共四Pa十ge一17页。密度工作原理1.当质量增加时，系统的谐振频率就减少。2.

当质量减少时，系统的谐振频率就增加。在高准质量流量计中，质量和谐振频率之间的关系是密度测量的基础。去理解这个关系，就认为是弹簧和质量系统。Micro

Motion

Confidential第十八页，共四Pa十ge一18页。密度工作原理Micro

Motion

Confidential第十九页，共四Pa十ge一19页。Micro

Motion

Confidential第二十页，共四Pa十ge一20页。密度标定系数密度标定系数(在标定时得出)K

1D

1K

2D

2Tc传感器注入低密度标定介质(空气)时的管道周期低密度标定介质的密度传感器注入高密度标定介质(水)时的管道周期高密度标定介质的密度温度变化100C时由于流量管刚性变化而引起的密度百分比误差Micro

Motion

Confidential第二十一页，共P四ag十e

2一1页。密度工作原理(=

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

RTDalso

represents

the

temperature

of

the

process

with

considerable

accuracy.

In

current

Micro

Motionsensor

design,theRTD

temperature

is

equivalent

to

a

thermowell

sensor

in

terms

of

indicating

process

temperature.Micro

Motion

Confidential第二十二页，共P四ag十e

2一2页。Micro

Motion

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2一3页。Micro

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2一4页。标准安装方式适当的重力支撑结构适当的法兰连接结构无需直管段Micro

Motion

Confidential第二十五页，共P四ag十e

2一5页。Micro

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2一6页。质量流量计的安装传感器的安装管线：上下游都不需要有直管段；调节阀要装到流量计的下游；在传感器的两侧安装截止阀；在传感器的两侧管段设置稳固的支撑；为便于调试及维护，考虑安装旁路。在测量易汽化介质时，传感器后建议工艺管与流量计保持同口径一段距离，以及传感器后安装阀门可以用以调节适当的背压，防止汽化或气穴发生。Micro

Motion

Confidential第二十七页，共P四ag十e

2一7页。质量流量计的安装变送器的安装位置要易于数据查看和维护。便于过程数据查看方便仪表组态与检查专用的仪表电源，保证仪表运行稳定，避免硬件损坏Micro

Motion

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2一8页。施工注意问题如为新建管线，在吹扫过程结束后再安装传感器；在管线上进行焊接作业时，要取下传感器；在安装大口径传感器时，不要将支撑物支撑在传感器外壳上。Micro

Motion

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2一9页。投表准备工作传感器、变送器接线检查及设备上电。检查仪表参数。仪表基本组态。仪表组态数据记录。注：上述组态项目可通过变送器的显示器、手操器或组态软件完成。Micro

Motion

Confidential第三十页，共四Pa十ge一30页。投表准备工作传感器、变送器接线检查及设备上电。专用信号电缆电源接线输出接线Micro

Motion

Confidential第三十一页，共P四ag十e

3一1页。投表准备工作仪表参数检查–传感器特性化参数、仪表系数等与设备铭牌、校准证书是否一致。Micro

Motion

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3一2页。投表准备工作仪表基本组态组态测量单位，根据需要选择过程变量的单位，包括质量流量、体积流量、温度、密度等；组态毫安输出或脉冲输出的过程变量与量程；组态过程变量阻尼，包括流量，密度，温度；组态流向；回路测试（数据远传）；仪表调零（并不总是需要）。Micro

Motion

Confidential第三十三页，共P四ag十e

3一3页。Qm

=

FCF

*

(△t

-

△t0)Qm：质量流量FCF：Flow

Cal

Factor

流量标定系数△t：由真实质量流量引起的相位差△t0

：FlowSignalOffsetAt

Zero

Flow(Zero

offset)零流量点的流量信号偏量零点影响零点影响不正确的零点会带来什么?改变了在Y轴的截距斜率

(仪表系数)没有变化ATrue

Mass

Flow

RateIndicated

Mass

Flow

RateA”A’%

Mass

Flow

Error

=(A”

–

A’)A’X

100

%MFMicro

Motion

Confidential第三十四页，共P四ag十e

3一4页。零点影响零点误差

(A’’-A’)流量

(A’)%误差1010,0000.1%101,0001.0%1010010.0%%质量流量误差=对不同的流量的影响是怎样的?(A”

–

A`