12.3
Pressure Measuring Test
The layout of the test and its setup are depicted in Fig. 12-2 "Setup of pressure
measuring test".
The pressure test checks the pressure chamber, the pressure sensors, and the
pressure measuring to ensure all elements are functioning properly. This test re-
quires the complete Single Use Cassette Tubing and a container filled with water.
The height of the water column (hydrostatic pressure) is used for measuring and
then converted to mm mercury column (mm Hg). The height of the water column
above the pressure chamber has to match the value of the actual pressure dis-
play after conversion.
Conversion formula: p (cm H2O) x 0.74 = p (mm Hg)
1. Hold the instrument tube into a container filled with water.
2. Set the nominal values:
• Nominal pressure = 50 mm Hg
• Max. flow = 1 l/min
3. Start pump.
Warning: The tubing behind the roller wheel must be filled completely with
fluid.
4. Stop the pump.
5. The actual pressure display (bar graph) shows approx. 0 mm Hg.
6. Hold the instrument tube at a level of approx. 67.5 cm above the cassette.
Make sure the tube segment between this point and the cassette is com-
pletely filled with fluid. Also make sure that none of the tube is higher than
the indicated value.
7. The height of the water column is used to calculate the generated hydrostatic
(water) pressure according to 67.5 cm H2O x 0.74 = 50 mm Hg.
8. The actual pressure display has to depict approx. 50 mm Hg (±10 mm Hg).
9. When varying the height of the tubing above the cartridge, the actual pres-
sure display changes accordingly.
The test of the pressure measurement is successfully completed when the values
of the actual pressure display correspond to those of the water column height.
Annual Inspection
Fig. 12-2 Setup of pressure measuring
test
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