
Insertion style magmeters have a sensor
at the end of a tube mounted in a housing
that is screwed into a threaded nipple.
The sensor electrodes are mounted in the
tip that protrudes into the pipe. A shutoff
valve (a ball valve is less prone to plugging
than a gate valve) is usually placed between
the meter and the nipple to close the hole
when not in use but a simple cap could also
be used.