Specifications

23
usings pH Housings pH Housings pH Housings pH Housings pH
1. Do I want a Guarded or Unguarded Housing?
The electrode/housing assembly can accidentally “ bump”
into the 25 mm por t when being installed. If the pH sens-
ing glass bulb of the electrode is not protected by a hous-
ing bulb guard, the electrode can easily be shattered. A
guarded housing design is often the engineer’s first choice
when choosing an electrode housing.
However, sometimes the media is so viscous that it will
clog the housing guard and effectively smother the pH
s
ensing glass bulb. In this case, an unguarded housing
must be used to ensure that the pH sensing glass bulb is
always in contact with fresh media.
2. When do I Choose a Longer Housing Length?
Sometimes the tank wall can become coated with a thick
layer of viscous material that does not mix well with the
rest of the media. If the pH sensing bulb of the electrode is
located just a couple of inches inside the tank wall, the
bulb might be smothered by this viscous layer. Subsequent
pH readi
ngs may not be representative of the bulk of the
media circulating in the rest of the tank. In the illustration
at the right, the pH electrode’s bulb is trapped in this slow
moving viscous layer near the tank wall. The electrode is
only measuring the pH of this layer.
A solution to the problem described above is to choose an
electrode and a matching housing that extends further into
the tank.This will position the pH sensing bulb away from the
tank wall and place it closer to the circ
ulating media further
inside the tank. The subsequent pH measurements will be
much more representative of the circulating media. In the
illustration to the right, the electrode and the housing pro-
trude past the viscous zone and into the area of well stirred
and circulated media within the production tank.
The F-615/326
assembly with
unguarded housing.
Recommended for
viscous media to
ensure that the pH
sensing bulb of
the electrode is
always in contact
with fresh media.
The F
-615/336
assem
bl
y with
guarded housing to
protect the pH glass
bulb of the electrode
during installation.
Bulb of electrode is trapped in thick viscous layer near the wall of the tank.
A longer electrode and housing extend further into the tank. The sensing bulb of
the pH electrode is past the viscous zone.
Two Most Frequently asked Questions
Broadley-James Corporation (U.S. & Canada) Toll-Free: 800-288-2833 E-mail: [e-mail]
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