(19)
(11) EP 0 121 437 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
23.01.1985 Bulletin 1985/04

(43) Date of publication A2:
10.10.1984 Bulletin 1984/41

(21) Application number: 84302239

(22) Date of filing: 02.04.1984
(84) Designated Contracting States:
AT BE CH DE FR GB IT LI LU NL SE

(30) Priority: 31.03.1983 GB 8308902

(71) Applicant: MONARFLEX LIMITED
 ()

(72) Inventor:
  • Kelsall-Spurr, John Kenneth Francis
     ()

   


(54) Control system for a boiler or furnace


(57) A control system for a boiler or furnace (2) extracts from the flue (4) a sample portion of the burnt flue gas. The level of unburnt oxygen therein is detected and compared with a stored reference level which, for the particular fuel supply rate, is indicative of efficient boiler orfumace operation. If the detected oxygen level differs from said stored reference level by more than a predetermined amountthe relative proportion of fuel and air in the mixture is adjusted in the appropriate sense, priortothe burntflue gas being re-tested. Before detection the sample portion is passed through a trap (18) having a condenser portion from which liquid condensed from the sample portion drains into a sump portion. The condensed liquid is automatically drawn from the sump portion at intervals by a siphonic duct.






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