Emerson Rosemount 3051 Reference Manual page 57

Reference Manual
00809-0100-4007
B
A. Drain/vent valves
B. Flow
Best practices
The piping between the process and the transmitter must accurately transfer the pressure
to obtain accurate measurements. There are five possible sources of error: pressure
transfer, leaks, friction loss (particularly if purging is used), trapped gas in a liquid line,
liquid in a gas line, and density variations between the legs.
The best location for the transmitter in relation to the process pipe is dependent on the
process. Use the following guidelines to determine transmitter location and placement of
impulse piping.
• Keep impulse piping as short as possible.
• For liquid service, slope the impulse piping at least 1 in./ft. (8 cm/m) upward from the
transmitter toward the process connection.
• For gas service, slope the piping at least 1 in./ft. (8 cm/m) downward from the
transmitter toward the process connection.
• Avoid high points in liquid lines and low points in gas lines.
• Make sure impulse legs are the same temperature.
• Use impulse piping large enough to avoid friction effects and blockage.
• Vent all gas from liquid piping legs.
Reference Manual
A
A
B
Hardware installation
August 2019
B
A
57