Functional Description - Hach PHOSPHAX sigma Manual Básico Del Usuario

Figure 8 Hose plan
1 Pump outlet
2 Drain hose violet
3 Safety valve
4 Digestion cuvette
5 Pump reagent A
6 Pump reagent C, D
7 Dosing hose yellow
8 Dosing hose black
9 Dosing hose orange
10 Lower cuvette holder
English 96
11 Hose pinch valve Q1
12 Sample/reagent/standard B
pumps
13 Sample hose blue
14 Hose pinch valve QA
15 Hose pinch valve Q2
16 Valve hose red
17 Refrigerator
18 Standard
19 Drain
20 Sample feed

Functional description

Total phosphorus determination
In the measurement operation, the cuvette is first rinsed with the
sample, before reagent A and the homogenized sample is fed into the
cuvette. After successful mixing, the solution is briefly heated under
pressure and immediately cooled again. To determine the phosphorus
compounds now converted to orthophosphate, the reagents C and D are
fed simultaneously via the reagent dosing pump into the cuvette and
mixed. The LED photometer now determines through the intensity of the
developing blue coloration, taking into account the zero value
determined shortly before, the total phosphorus concentration.
Orthophosphate determination (depending on design)
In the measurement operation, the cuvette is first rinsed with the
sample. Then reagent A is fed into the cuvette. Through the heating, the
thermal conversion of the oxidant into sulfuric acid occurs. After the
cooling, the sample, reagent C and reagent D are fed in via the dosing
pumps. After the mixing- and reaction phase, the measurement occurs
via the LED photometer.
Calibration (approximately 15 minutes)
The process photometer PHOSPHAX Σ sigma is calibrated
automatically through a two-point measurement. The first measurement
point is determined in the course of zero point determination for each
individual measurement, the second measurement point is determined
in the course of calibration with the standard solution. The exact
concentration level for the standard solution is located on each individual
bottle
(1.95–2.05 mg/L P) and is entered in the [+SETTINGS] menu under
menu item [STANDARD].
Calibration should always then be triggered if changes have been made
to the following device components:
• Reagents
• Dosing hoses
• Dosing pumps
• Cuvette