Document ID: chunk:federal_register_of_legislation:F2024C00356:reg:21:p11
Version: federal_register_of_legislation:F2024C00356
Segment Type: reg
Provision Reference: reg 21 (pt 11/35)
Character Range: 317491–320665

2.2.7. The air flow rate (Qs) at each test point is calculated in standard m3/min from the flow-meter data using the manufacturer's prescribed method.
              2.2.8. The air flow-rate is then converted to pump flow (V0) in m3/rev at absolute pump inlet temperature and pressure.

Where:
 V0     =  pump flow rate at Tp and Pp (m3/rev),
 Qs     =  air flow at 101.33 kPa and 273.2 K (m3/min),
 Tp     =  pump inlet temperature (K),
 Pp     =  absolute pump inlet pressure (kPa),
 N      =  pump speed (min-1).

              2.2.9. To compensate for the interaction of pump speed pressure variations at the pump and the pump slip rate, the correlation function (x0) between the pump speed (n), the pressure differential from pump inlet to pump outlet and the absolute pump outlet pressure is then calculated as follows:

 Where:
 x0      =  correlation function,
 ΔPp     =  pressure differential from pump inlet to pump outlet (kPa),
 Pe      =  absolute outlet pressure (PPO + Pb) (kPa).

               A linear least-square fit is performed to generate the calibration equations which have the formula:

           V0 = D0 - M (x0)

           n = A - B (ΔPp)

           D0, M, A and B are the slope-intercept constants describing the lines.

              2.2.10. A CVS system that has multiple speeds shall be calibrated on each speed used. The calibration curves generated for the ranges shall be approximately parallel and the intercept values (D0) shall increase as the pump flow range decreases.
              2.2.11. If the calibration has been performed carefully, the calculated values from the equation will be within 0.5 per cent of the measured value of V0. Values of M will vary from one pump to another. Calibration is performed at pump start-up and after major maintenance.
              2.3. Calibration of the critical-flow venturi (CFV)
              2.3.1. Calibration of the CFV is based upon the flow equation for a critical venturi:

 Where:
 Qs      =  flow,
 Kv      =  calibration coefficient,
 P       =  absolute pressure (kPa),
 T       =  absolute temperature (K).

                Gas flow is a function of inlet pressure and temperature.
                The calibration procedure described below establishes the value of the calibration               coefficient at measured values of pressure, temperature and air flow.
              2.3.2. The manufacturer's recommended procedure shall be followed for calibrating electronic portions of the CFV.
              2.3.3. Measurements for flow calibration of the critical flow venturi are required and the following data shall be found within the limits of precision given:

                Barometric pressure (corrected) (Pb) 0.03 kPa,

                LFE air temperature, flow-meter (ETI) 0.15 K,

                Pressure depression upstream of LFE (EPI) 0.01 kPa,

                Pressure drop across (EDP) LFE matrix  0.0015 kPa,

                Air flow (Qs) 0.5 per cent,

                CFV inlet depression (PPI) 0.02 kPa,

                Temperature at venturi inlet (Tv) 0.2 K.

              2.3.4. The equipment shall be set up as shown in