Ecotech HiVol 3000

HiVol 3000 User Manual 1.7 Calibration
55
calibration, if required. The zero flow-rate point is not used as a calibration
point in the HiVol 3000.
The three-point calibration ensures accuracy at any point within the range of
the sampler. The HiVol fits a quadratic curve to linearise the signal to display
conversion automatically. The flow-rate may be changed to a flow-rate other
than the calibration flow-rate without introducing non-linearity errors.
After calibration of the HiVol, the flow rate indication should be checked at a
minimum of 3 flow rates spaced over the range 61 to 75 m
3
/hour to comply
with U.S. EPA requirements.
4.1.3 Flow rate calibration procedure
1. Where an Orifice Plate is being used to calibrate the HiVol 3000, use the
Calibration Chart supplied with the Orifice Plate (or the formula given in
Equation 1) to obtain the manometer pressures, *H (mm of H2O or kPa),
at the three flow-rate used for calibration – 60, 70, 80m
3
/h.
2. Raise the inlet hood. Remove the filter from the filter cassette then install
the orifice plate on top of the cassette. The assembly is fastened with two
thumb screws, one on either side of the filter cassette. Firmly finger
tighten the two thumb screws to ensure a good seal (without bending the
plate). Connect a U-tube water manometer to the port on the side of the
orifice plate, with a length of flexible tubing. If necessary, add or remove
water or slide the tube up and down until the water sits level in the tube
and reads zero. See Figure 19. Alternatively, a digital manometer may be
used in place of the water manometer.
Note: ensure the thumb screws are tightened
firmly as the failure to do this will result in leak
through the seal and an invalid calibration.
3. Make sure there are no leaks between the sampler and orifice plate.
Check that the flexible tube is connected securely.
4.
From the Main Screen, go to the Main Menu  Calibration Menu 
Start Cal then press Enter. The HiVol motor will automatically start up.
Allow at least 5 minutes for the sampler to warm-up.
5.
Use the arrow keys to go to the second line: MOTOR ADJUST. Press
Select and the cursor will appear under ADJUST. Use the Up and Down
arrows to adjust the motor speed until the manometer indicates the
pressure that corresponds to the flow rate indicated on the first line.
Allow the manometer a few seconds to stabilise between each
adjustment.
Note: the HiVol remembers each point from
previous calibrations so that the required
adjustments are minimised.