Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p42
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 42/108)
Character Range: 1002127–1005274

Pp, m3/rev;
           Qs is the air flow at 101.325 kPa and 273.15 K (0 °C), m3/min;
           Tp is the pump inlet temperature, Kelvin (K);
           Pp is the absolute pump inlet pressure, kPa;
           n is the pump speed, min-1.
              3.4.2.5.4. To compensate for the interaction of pump speed pressure variations at the pump and the pump slip rate, the correlation function  between the pump speed , the pressure differential from pump inlet to pump outlet and the absolute pump outlet pressure shall be calculated using the following equation:
           where:
           x0 is the correlation function;
            is the pressure differential from pump inlet to pump outlet, kPa;
            Pe absolute outlet pressure (PPO + Pb), kPa.
              A linear least squares fit shall be performed to generate the calibration equations having the following form:
              where B and M are the slopes, and A and D0 are the intercepts of the lines.
              3.4.2.6. A CVS system having multiple speeds shall be calibrated at 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.
              3.4.2.7. The calculated values from the equation shall be within 0.5 per cent of the measured value of V0. Values of  will vary from one pump to another. A calibration shall be performed at initial installation and after major maintenance.
              3.4.3. Calibration of a critical flow venturi (CFV)
              3.4.3.1. Calibration of a CFV is based upon the flow equation for a critical venturi:
           where:
           Qs is the flow, m³/min;
           Kv is the calibration coefficient;
           P is the absolute pressure, kPa;
           T is the absolute temperature, Kelvin (K).
           Gas flow is a function of inlet pressure and temperature.
              The calibration procedure described in paragraphs 3.4.3.2. to 3.4.3.3.3.4. inclusive of this annex establishes the value of the calibration coefficient at measured values of pressure, temperature and air flow.
              3.4.3.2. Measurements for flow calibration of a critical flow venturi are required and the following data shall be within the limits of accuracy given:
           Barometric pressure (corrected), Pb ±0.03 kPa,
           LFE air temperature, flow meter, ETI ±0.15 °C,
           Pressure depression upstream of LFE, EPI ±0.01 kPa,
           Pressure drop across LFE matrix, EDP ±0.0015 kPa,
           Air flow, Qs ±0.5 per cent,
           CFV inlet depression, PPI ±0.02 kPa,
           Temperature at venturi inlet, Tv ±0.2 °C.
              3.4.3.3. The equipment shall be set up as shown in Figure A5/7 and checked for leaks. Any leaks between the flow-measuring device and the critical flow venturi will seriously affect the accuracy of the calibration and shall therefore be prevented.

Figure A5/7
CFV calibration configuration
              3.4.3.3.1. The variable-flow restrictor shall be set to the open position, the suction device shall be started and the system stabilized. Data