Flame detection device

A flame detection device for a furnace, comprising a flame signal receiver, a flame signal passage and a flame signal transmitting mechanism, wherein, the flame signal passage passes into an inner portion of the furnace through a furnace shell and comprises an outside-furnace passage portion and an inside-furnace passage portion;

• wherein a pressure-resistant optical mechanism is configured to be directly or indirectly connected to an outermost end of the outside-furnace passage portion on one side thereof and to the flame signal receiver on the other side, so as to transparently separate the flame signal receiver from the flame signal passage and thus prevent a gas within the furnace from affecting the flame signal receiver;
• the pressure-resistant optical mechanism including a mounting flange having a planar mounting surface with a recess and a passage formed therein, a compressing flange having a passage formed therein, the compressing flange being seated on the mounting surface surrounding the recess and being coupled to the mounting surface via a plurality of bolts that are received in through-holes formed in the compressing flange, a transparent member received within the recess and arranged between the mounting flange passage and the compressing flange passage, and a temperature-resistant sealing member surrounding the transparent member such that tightening of said bolts compresses the temperature-resistant sealing member;
• and
• a pressure-resistant protective enclosure that is seated on the mounting surface and that includes a plurality of bolt holes formed therein for sealingly coupling to the mounting flange and that is arranged such that the pressure-resistant protective enclosure envelops the compressing flange and the flame signal receiver;
• wherein the inside-furnace passage portion is provided with a cooling mechanism.