The Measurement / Reference Cycle; Table 10-2: T700 Photometer Measurement / Reference Cycle - Teledyne T700 Operation Manual

Principles of Operation

10.7.1.2. The Measurement / Reference Cycle

Table 10-2: T700 Photometer Measurement / Reference Cycle

TIME INDEX STATUS
0 sec. Measure/Reference Valve Opens to the Measure Path.
0 – 2 sec. Wait Period. Ensures that the absorption tube has been adequately flushed of any
previously present gases.
2 – 3 Seconds
Calibrator measures the average UV light intensity of O
during this period
3 sec. Measure/Reference Valve Opens to the Reference Path.
3 – 5 sec. Wait Period. Ensures that the absorption tube has been adequately flushed of O
bearing gas.
5 – 6 Seconds
Calibrator measures the average UV light intensity of Non-O
during this period
288
I
o
C = ln
I
The T700 photometer:

Measures each of the above variables: ambient temperature; ambient gas pressure;
the intensity of the UV light beam with and without O

Inserts know values for the length of the absorption path and the absorption
coefficient, and:

Calculates the concentration of O
In order to solve the Beer-Lambert equation, it is necessary to know the intensity of the
light passing through the absorption path both when O
valve called the measure/reference valve, physically located on front-left corner of the
O generator assembly (see Figure 3-6 and Figure 10-13) alternates the gas stream
3
flowing to the photometer between zero air (diluent gas) and the O
generator. This cycle takes about 6 seconds.
.
.
CYCLE REPEAT EVERY 6 SECONDS
Teledyne API – Model T700 Dynamic Dilution Calibrator
9
10
× ×
α
L
273
present in the sample gas.
3
Τ
29 . 92 inHg
×
Ρ
o
Κ
present;
3
is present and when it is not. A
3
output from the O
3
bearing Sample Gas
3
bearing Sample Gas
3
06873E DCN7106
3
(I)
3
(I )
0