TN5FCXA2VG-E
18
Cautions on impulse piping
• For liquid, the impulse pipes should have an downward slope of 1/10 or more between the pro-
cess connection and the transmitter to prevent accumulation of gas, etc. in the detecting unit.
• For gas, the impulse pipes should have a upward slope of 1/10 or more between the process
connection and transmitter to prevent accumulation of liquid or condensat, etc. in the detecting
unit.
• Avoid any sharp bends in impulse pipe which may cause gas or liquid to accumulate in the
impulse pipe.
• Do not apply an excessive force to impulse pipe during the connection.
• Install condensate chambers or vent drain when impulse pipes can not be inclined.
• The impulse pipes used should be suitable for the working temperature, pressure standards.
• During installation, avoid mechanical constrains of the transmitter connections.
• In case of external degradation (corrosion, overflow, shock ... etc) or in case of fire, the concerned
transmitter must be checked before commissioning.To avoid the deterioration of the transmitter
mounted externally, it will be mounted in a box protection.
• The transmitter should never be exposed to fire. In case of fire, the transmitter characteristics
need to be checked before started up. The transmitter must not be reused if it has been partially
or totally exposed to fire and heat.
• Freeze protection.
If the fluide can freeze, the transmitter and the impulse pipe must be warmed up with steam or a
heater.
Do not exceed the temperature limits (measuring cell: 120°C maxi and transmitter: 85°C).
Even when the installations shut down the heat must be maintained, if not the transmitter and
impulse pipes must be drained to prevent freezing.
H
1
ρ
h
ρ
1
Max. liquid
level
Min. liquid
level
Atmospheric
air inlet
Manifold
High
pressure
side
Low
pressure
side
(2) Reference column empty
For an open tank, leave the low pressure side of transmitter open to atmosphere.
Level calculation formula
LRV:
ρH
1
URV:
ρH
1
+ ρ
1
h
LRV: Low limit of measurement (0% point)
URV: High limit of measurement (100% point)
ρ,ρ
1
: Density
H
1
: Liquid level,
h : Liquid level change