Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:1800:p10
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 1800 (pt 10/12)
Character Range: 528844–531643

The particulate sampling system is required for collecting the particulates on the particulate filter and is shown in Figures 16 and 17. In the case of total sampling partial flow dilution, which consists of passing the entire diluted exhaust sample through the filters, the dilution and sampling systems usually form an integral unit (see Figure 12). In the case of fractional sampling partial flow dilution or full flow dilution, which consists of passing through the filters only a portion of the diluted exhaust, the dilution and sampling systems usually form different units.
               For a partial flow dilution system, a sample of the diluted exhaust gas is taken from the dilution tunnel DT through the particulate sampling probe PSP and the particulate transfer tube PTT by means of the sampling pump P, as shown in Figure 16. The sample is passed through the filter holder(s) FH that contain the particulate sampling filters. The sample flow rate is controlled by the flow controller FC2.

              For a full flow dilution system, a double dilution particulate sampling system shall be used, as shown in Figure 17. A sample of the diluted exhaust gas is transferred from the dilution tunnel DT through the particulate sampling probe PSP and the particulate transfer tube PTT to the secondary dilution tunnel SDT, where it is diluted once more. The sample is then passed through the filter holder(s) FH that contain the particulate sampling filters. The diluent flow rate is usually constant whereas the sample flow rate is controlled by the flow controller FC2. If electronic flow compensation EFC (see Figure 15) is used, the total diluted exhaust gas flow is used as command signal for FC2.

              Figure 16
              Scheme of particulate sampling system
              a = from dilution tunnel

              Figure 17
              Scheme of double dilution particulate sampling system
              a =  diluted exhaust from DT  b = optional  c = vent  d = secondary diluent

A.2.2.6. Components of Figure 16 (partial flow system only) and Figure 17 (full flow system only)
 PTT Particulate transfer tube
 The transfer tube:
(a) Shall be inert with respect to PM;
(b) May be heated to no greater than 325 K (52 °C) wall temperature;
(c) May be insulated.
 SDT Secondary dilution tunnel (Figure 17 only)
 The secondary dilution tunnel:
(a) Shall be of sufficient length and diameter so as to comply with the residence time requirements of paragraph 9.4.2.(f) of this annex;
(b) May be heated to no greater than 325 K (52 °C) wall temperature;
(c) May be insulated.
 FH Filter holder
 The filter holder:
(a) Shall have a 12.5° (from center) divergent cone angle to transition from the transfer line diameter to the exposed diameter of the filter face;
(b) May be