Introduction; General Information; Requirements; Contents Of Kit - Abb 8012 Operating Instructions Manual

1 INTRODUCTION

The Model 8012 Dissolved Oxygen
probe is designed to give a direct readout
of dissolved oxygen concentrations in
parts per million (ppm) in fresh water,
when connected to a conventional pH/
mV meter. Using a simple setting-up
procedure the probe can be calibrated to
measure concentrations in the range 0
to14 ppm directly from the pH meter
scale. The probe can be used for
laboratory dissolved
measurements, and is particularly suited
for the B.O.D. (Biochemical Oxygen
Demand) test, which estimates the
amount of oxygen
microscopic organisms in a water sample
over a prescribed period.
The Model 8012 comprises an oxygen
sensor capsule (a silver/lead galvanic
cell) connected to a miniaturised circuit
within the probe body. This circuit
converts the current output of the
capsule, produced
electrochemical reduction of oxygen
diffusing into it from the sample, to a
millivolt signal compatible with the input
requirements of a pH/mV meter. The
circuit is powered
disposable cells contained in the probe
body. Automatic
compensation is carried out using a
thermistor mounted on the probe stem
close to the
adjustable control at the top of the probe
body is used to calibrate the probe and
meter combination.
The Model 8012 is supplied as part of a
kit which includes two clip-on stirrer
attachments, twelve cells, a spare sensor
capsule, and a displacement funnel (with
adaptor) for the B.O.D. bottle.
2
oxygen
consumed
by
from four
temperature
sensor capsule.

2 GENERAL INFORMATION

2.1 Requirements

In addition to the Model 8012 and the
contents of the kit, the following will be
required:
• A pH/mV with either a millivolt
measuring range of at least 0
to1400mV (i.e. so that 100mV
corresponds to 1 ppm O2) or a 0 to
14pH range (so that 1pH unit
corresponds to 1 ppm O2) with a
back-off zero control capable of
making the zero of the probe
correspond to 0pH on the meter
by
scale.
• A magnetic stirrer.
• A 5% solution of sodium sulphite
(zero-concentration
oxygen).
• A means of producing fully-aerated
the
water at a controlled temperature.
• A mercury-in-glass
scaled 0 to 100°C or 0 to 50°C.

2.2 Contents of Kit

tiny
The complete contents of the Model 8012
kit (Fig 2.1) are:
Qty Description
An
1 Model 8012 Probe body.
2 Stirrer bar attachments, (one
with long spindle, one with short
spindle).
2 Sensor capsules, in protective
containers.
1 Displacement
adaptor) for the B.O.D. test - the
funnel (and cover) may be used
for B.O.D. bottles with narrow
necks, whilst adding the knurled
adaptor enables the funnel to be
used on B.O.D. bottles with wide-
tapered necks.
12 Disposable cells (in two sealed
packs of six cells).
1 Instruction manual.
dissolved
thermometer,
funnel (with