UMSITRPDS3-1 Installation
November 2005
4-9
MG00348b
Closed Tank, Non-Condensing Atmosphere, Level Measurement
Blowdown
Valve
Non-Condensing
Atmosphere
Dry Line Leg
Open Tank, Level Measurement
Span
H
1
Low Pressure
Side Vented to
Atmosphere
Flange on High
Pressure Side
Closed Tank, Condensing Atmosphere, Level Measurement
Blowdown
Valve
Condensing
Atmosphere
Flange on High
Pressure Side
Low Pressure
Side
H
1
Plugged
Filling "T"
Filled
Reference
Line
Max. Level
Min. Level
Span
H
1
Max. Level
Min. Level
Span
H
2
Min. Level
Max. Level
Notes:
1. Transmitter may be mounted at or below the
minimum level to be measured.
2. Open or vented vessels require only a high pressure
(HP) connection.
3. High pressure line senses static pressure plus level.
Low pressure line senses pressure only. The two
pressures oppose each other, canceling the effect
of static pressure.
4. Distance "X" can be any distance since both high
and low pressure lines have equal and opposite
forces which cancel the forces created by this
distance.
5. Entire length of low pressure pipe is kept full of
condensate to act as a reference.
6. See Appendix C for information on calculating
suppressed and elevated zero ranges.
FIGURE 4-5 Open and Closed Tank Level Measurement, Flange Mounted Transmitters
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