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Typical examples of piping
(1) Level measurement on opened tank
An open tank should be piped so that the
fl
ange on
the low pressure side is open to atmosphere.
Level calculation formula:
Zero:
ρ
E +
ρ
’h'
Span:
ρ
(E + h) +
ρ
’h'
LRV: Low limit of measurement (0%)
URV: High limit of measurement (100%)
ρ
: Measuring liquid density
ρ
’: Seal liquid density
(2) Level measurement on closed tank
Connect the highest liquid level tapping of
tank to the low pressure side of transmitter,
and the low liquid level tapping of tank to the
high pressure side of transmitter
Level calculation formula:
Zero: (-h' .
ρ
') +
ρ
.E
Span: (-h' .
ρ
') +
ρ
(E +h)
LRV: Low limit of measurement (0%)
URV: High limit of measurement (100%)
ρ
: Measuring liquid density
ρ
’: Seal liquid density
The transmitter body should be installed below any pressure receiving
unit. This is mandatory where process pressure may become vacuum
due to application.
PRECAUTION
Max. liquid level
Min. liquid level
High pressure
side
Low
pressure
side
h
h’
R
R
’
E
Max. liquid level
Min. liquid level
High
pressure
side
Low
pressure
side
h
R
R
’
E
h’
