4.2Piping ST 3000 Transmitter

Summary

The actual piping arrangement will vary depending upon the process

 

measurement requirements and the transmitter model. Except for

 

flanged and remote diaphragm seal connections, process connections are

 

made to ¼ inch or ½ inch NPT female connections in the process head

 

of the transmitter’s meter body. For example, a differential pressure

 

transmitter comes with double ended process heads with ¼ inch NPT

 

connections but they can be modified to accept ½ inch NPT through

 

optional flange adapters. Some gauge pressure transmitters may have a

 

½ inch NPT connection which mounts directly to a process pipe.

 

The most common type of pipe used is ½ inch schedule 80 steel pipe.

 

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 rezero a transmitter without interrupting the process. It

 

also accommodates the installation of blow-down valves to clear debris

 

from pressure lines to the transmitter.

 

Figure 11 shows a diagram of a typical piping arrangement using a

 

three-valve manifold and blow-down lines for a differential pressure

 

transmitter being used to measure flow.

Figure 11

Typical 3-Valve Manifold and Blow-Down Piping

 

 

Arrangement.

 

 

 

 

 

 

 

 

 

To Downstream Tap

To Upstream Tap

 

 

 

 

Blow-Down

 

3-Valve

 

Blow-Down

 

 

Valve

 

Manifold

 

Valve

 

 

Blow-Down

 

 

Blow-Down

Piping

 

 

 

 

Piping

 

 

 

 

 

 

 

 

To Low Pressure

 

To High Pressure

Side of Transmitter

 

Side of Transmitter

To Waste

 

 

To Waste

 

 

 

21010

 

 

 

 

 

 

 

 

 

 

 

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ST 3000 Release 300 Installation Guide

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