Ge-pw Brand's Products

3 Planning instructions for isolating systems

Chemical seal CSB • for VEGADIF 65

36133-EN-130417

Filling oil Permissible

product temper-

atures

Permissible

product tem-

peratures at

0.05 bar

abs

< p

< 1 bar

abs

Densi-

ty in g/

cm³

Vis-

cosity

in m

s•10

-6

Expan-

sion

coe-

cient 1/K

Cor-

rective

factor

for TK

Application

area

Halocarbon oil

KN21(BAM

tested)

-40…+150°C(-

40 … +302 °F)

-40…+80°C(-

40 … +176 °F)

1.968

up to

20 °C

up to

20 °C

0.00086 0.83 For oxygen

and chlorine

applications

Med. white oil

KN92(FDA

approved)

-10 … +250 °C

(+14…+482°F)

-10 … +160 °C

(+14…+320°F)

0.85

up to

20 °C

5.6

up to

40 °C

0.00065 0.63 suitable for

foodstus

TheimplementedllingoilalsoinuencestheTK

zeropoint

,thepermis-

sible ambient temperature and the step response time of a chemical

seal. See also chapter "

Inuenceofthetemperaturetothezeropoint"

and "Step response time".

Thedierentialpressuretransmitteralsoinuencesthetemperature

applicationrange,theTK

zeropoint

and the step response time of the iso-

latingsystemthroughthevolumeofitslateralangesanditscontrol

volume.

3.2 Inuenceoftemperaturechanges

Thellingoilexpandsasthetemperatureincreases.Theadditional

volumepressesonthechemicalseal.Themorerigidthediaphragm,

the more it counteracts a volume change. The additional volume also

adds to the process pressure on the measuring cell and thus shifts

thezeropoint.Therespectivetemperaturecoecient"TK

Process

" is

listed in chapter "Dimensions and weights".

Thefollowingdiagramshowsthetemperaturecoecientdepending

on the capillary length. The process temperature corresponds to the

calibrationtemperature.Thetemperaturecoecientsdetermined

from the diagram apply to silicone oil and the diaphragm material

316L.Forotherllingoil,thesetemperaturecoecientshavetobe

multipliedwiththecorrectionfactorfortheTKoftherespectivelling

oil.

Dierentialpressure

transmitter

Inuenceofthetempera-

ture to the zero point

The control volume is the volume that must be shifted in order to utilise the

complete measuring range.