Piping The St 700 Transmitter; Piping Arrangements; Figure 11 - Typical 3-Valve Manifold With Blow-Down Piping - Honeywell ST 700 User Manual

3.5 Piping the ST 700 Transmitter

3.5.1 Piping Arrangements

Piping arrangements vary depending upon process measurement requirements and the Transmitter
model. For example, a differential pressure transmitter comes with double-ended process heads with
¼-inch NPT connections, which can be modified to accept ½-inch NPT through optional flange
adapters. Gauge pressure transmitters are available with various connections for direct mounting to a
process pipe.
A ½-inch, schedule 80, steel pipe is commonly used for Transmitter integration into a process system.
Many piping arrangements use a three-valve manifold to connect the process piping to the
Transmitter. A manifold makes it easy to install and remove or re-zero a Transmitter without
interrupting the process. A manifold also accommodates the installation of blow-down valves to clear
debris from pressure lines. Figure 11 represents a typical piping arrangement using a three-valve
manifold and blow-down lines for a differential pressure transmitter being used to measure flow.
To Downstream Tap
Blow-Down
Valve
Blow-Down
Piping
Figure 11 – Typical 3-Valve Manifold with Blow-Down Piping
Page 72
3-Valve
Manifold
To Low Pressure
Side of Transmitter
To Waste
ST 700 SmartLine Pressure Transmitters User's Manual
To Upstream Tap
Blow-Down
Piping
To High Pressure
Side of Transmitter
To Waste
Blow-Down
Valve
Revision 1.0