packing nut to form a watertight seal. The packing
operates on the principle that an increase in
nut has a set screw that screws into a groove in the
electrolytic impurities (salt) will increase the
cell tube to prevent axial displacement of the tube by
conductivity of the water. Therefore, the higher the
the hydrostatic pressure. A steel ring stop on the cell
impurities, the higher the current.
tube, between the packing nut and the nipple, locates
The salinity cell is a self-contained unit consisting
the cell properly in the piping.
of a nipple, packing nut, cell tube, and electrode
assembly. The cell tube provides a means of
A 6-foot, three-conductor cable connects the cell to
extending the electrode assembly through the valve
the salinity indicating panel and the ship's 115-volt,
and is connected to the tee through the nipple and
Figure 10-41.--Salinity indicator panel.