© Siemens AG 2008

SITRANS P measuring instruments for pressure

Remote seals

Measuring setups without remote seals

Measuring setups for closed containers

Static

pressure

2

Ho

Hu

Maximum level

Full-scale value

Start-of-scale value

r

Gas-filled negative pressure line

Level measurement, Version 1

Start-of-scale: DpMA = r · g · HU

Full-scale:

DpME = r · g · HO

Legend

 

DpMA

Start-of-scale value to be set

DpME

Full-scale value to be set

rDensity of medium in vessel

gLocal acceleration due to gravity

HU

Start-of-scale value

HO

Full-scale value

Transmitter reference line

Maximum level

Static

pressure

Constant level

Static

pressure

Separation layer measurement

Start-of-scale: DpMA = g · (HU · r1 + (HO - HU) · r2 - HV · r'2)

 

 

 

Max. separation layer

 

 

 

 

Full-scale value

 

 

 

 

Start-of-scale value

r2

 

 

 

H o

 

 

r1

 

 

H

 

u

 

 

 

 

 

 

 

r' 2

Transmitter reference line

Full-scale:

Legend

DpMA

DpME

r1

H v

r2

 

r'2

g

HU HO HV

DpME = g · (HO · r1 - HV · r'2)

Start-of-scale value to be set Full-scale value to be set

Density of heavier liquid with separation layer in vessel

Density of lighter liquid with separation layer

Density of liquid in the negative pressure line

(corresponding to the temperature existing there) Local acceleration due to gravity Start-of-scale value

Full-scale value

Distance between the measuring points (spigots)

2/186

Siemens FI 01 · 2009

Page 186
Image 186
Siemens P technical specifications 186, Measuring setups for closed containers