Liquid Level Measurement - Pressurized Tank; Figure 42 Typical Piping Arrangement For Liquid Level Measurement With Dp Type Transmitter And Pressurized Tank - Honeywell ST 3000 User Manual

7.7

Liquid Level Measurement - Pressurized Tank

Procedure
Figure 42 Typical Piping Arrangement for Liquid Level Measurement with DP Type
Tap location at the
minimum level to be
measured
ATTENTION
6/05 ST 3000 Release 300 and SFC Model STS103 User's Manual
The procedure in Table 42 outlines the steps for starting up a differential
pressure (DP) type transmitter in a liquid level measurement application
for a pressurized tank with a liquid-filled (wet) reference leg. Refer to
Figure 42 for the piping arrangement identification and Figure 38 for
typical SFC and meter connections.
Transmitter and Pressurized Tank
Valve B
Plug C at
zero level
Valve A
h
For the procedure in Table 42, we are assuming that:
• The tank is empty and the reference leg is filled.
• The high pressure (HP) side of the transmitter is connected to the
wet reference leg. Note that the transmitter will work if the HP side
is connected to the bottom of the tank, but not within the guaranteed
accuracy specifications.
• The transmitter is mounted below the zero level of the tank, so "h" is
greater than zero. If h equals zero, plug C is eliminated from the
piping and the LP vent is opened instead.
Plug D
H 1
Differential
Pressure
Transmitter
HP side of transmitter
Continued on next page
137