One common misconception about pressure regulators is that they only control pressure immediately upstream or downstream of the valve. However, most pilot-operated regulators and some self-operated regulators operate using an external control or sensing line. This line can be used to control pressure at a remote location in the process pipeline, and there are a variety of reasons for doing so.
Some reasons for using an external control line include:
- Wanting to control pressure more accurately at a specific location in the process upstream or downstream from the regulator
- Lack of space which might require a remote regulator installation
- Regulator monitor setups that require an external control line
Whatever the reason for using an external control line, it is important to remember that the control line is the nervous system of the regulator. One common cause of system pressure control issues is incorrect installation of control lines. Some things to keep in mind when using control lines are:
The above tips are just general guidelines, and as every application is different customers may find themselves unable to follow them to the letter. If you have questions about control line installations or best practice recommendations, please feel free to comment.