Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:9:p60
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 9 (pt 60/71)
Character Range: 377739–380678

325 K (52 °C) prior to the introduction of the exhaust in the dilution tunnel;

                —    may be insulated.

              P Sampling pump (Figures 21, 22)

              The particulate sampling pump shall be located sufficiently distant from the tunnel so that the inlet gas temperature is maintained constant (± 3 K), if flow correction by FC3 is not used.

              DP Dilution air pump (Figure 22)

              The dilution air pump shall be located so that the secondary dilution air is supplied at a temperature of 298 K ± 5 K (25 °C ± 5 °C), if the dilution air is not preheated.

              FC3 Flow controller (Figures 21, 22)

              A flow controller shall be used to compensate the particulate sample flow rate for temperature and backpressure variations in the sample path, if no other means are available. The flow controller is required if electronic flow compensation EFC (see Figure 20) is used.

              FM3 Flow measurement device (Figures 21, 22)

              The gas meter or flow instrumentation for the particulate sample flow shall be located sufficiently distant from the sampling pump P so that the inlet gas temperature remains constant (± 3 K), if flow correction by FC3 is not used.

              FM4 Flow measurement device (Figure 22)

              The gas meter or flow instrumentation for the dilution air flow shall be located so that the inlet gas temperature remains at 298 K ± 5 K (25 °C ± 5 °C).

              BV Ball valve (optional)

              The ball valve shall have an inside diameter not less than the inside diameter of the particulate transfer tube PTT, and a switching time of less than 0,5 seconds.

                  Note: If the ambient temperature in the vicinity of PSP, PTT, SDT, and FH is below 293 K (20 °C), precautions should be taken to avoid particle losses onto the cool wall of these parts. Therefore, heating and/or insulating these parts within the limits given in the respective descriptions is recommended. It is also recommended that the filter face temperature during sampling be not below 293 K (20 °C).

                  At high engine loads, the above parts may be cooled by a non-aggressive means such as a circulating fan, as long as the temperature of the cooling medium is not below 293 K (20 °C).

3.                                DETERMINATION OF SMOKE

3.1.                            Introduction

              Sections 3.2 and 3.3 and Figures 23 and 24 contain detailed descriptions of the recommended opacimeter systems. Since various configurations can produce equivalent results, exact conformance with Figures 23 and 24 is not required. Additional components such as instruments, valves, solenoids, pumps, and switches may be used to provide additional information and coordinate the functions of the component systems. Other components which are not needed to maintain the accuracy on some systems, may be