KST – KROMSCHRÖDER SYSTEM TECHNOLOGY
The safety time and total closing time shall not vary by more than 20 % when the electrical supply voltage is varied between 85 % and 110 % of the nominal value.
188.8.131.52.4.2 Maximum safety times for natural draught burners
The safety time and total closing time for natural draught burners shall not exceed the values given in Tables 1 and 2.
184.108.40.206.4.3 Maximum safety times for forced and induced draught burners
The maximum start gas rate and the corresponding safety time for forced and induced draught burners shall not exceed the values given in Table 3.
The total closing time shall not exceed 3 s.
Burner start-up shall be achieved in accordance with one of the following methods:
- direct ignition of the main burner at full rate (see Table 3, Column 2); or
- direct ignition of the main burner at reduced rate e.g. by using slow opening valve; (see Table 3, Column 3); or
- direct ignition of the main burner at reduced rate with by-pass start gas supply to a separate gas inlet of the burner or two step safety valve; (see Table 3, Column 4); or
- ignition of the main burner by means of an independent pilot burner; (see Table 3, Column 5).
For methods of burner start-up see Annex D.
Higher start gas rates than those specified in Table 3 may be achieved at the end of the safety time provided that it is proved that the total amount of energy released in the combustion chamber during the safety time is not greater than the energy release calculated by multiplying the values of maximum start gas heat input and safety time given by Table 3.
The following chapters are printed with the permission of the DIN Deutsches Institut für Normung e.V. (German Institute for Standardization). For the implementation of the DIN Standard, the version with the most recent issue date is deemed authoritative. This is available from Beuth Verlag GmbH, Burggrafenstrasse 6, 10787 Berlin, Germany.