Jet-type direct-fired preheating system

A jet direct fire preheating system, which comprises:

• a direct fire furnace, a preheating furnace;
• wherein
• the direct fire furnace comprises:
• a furnace shell, wherein a furnace top roller chamber and a furnace bottom roller chamber are respectively provided at the upper and lower ends;
• steering rollers are respectively arranged in the furnace top roller chamber and the furnace bottom roller chamber;
• a plurality of direct fire heating zones are arranged in the furnace shell along the height direction, and a plurality of direct fire burners are arranged in the direct-fire heating zone;
• at least two through-holes are provided on the upper side wall of the furnace shell, and are symmetrically arranged on the left and right;
• the preheating furnace comprises:
• a furnace body, which is provided with at least two connecting holes on the upper side wall, symmetrically arranged on the left and right, wherein the connecting holes connect through holes of the upper part of the furnace shell of the direct fire furnace through a communicating pipe respectively;
• wherein the top of the furnace body is provided with a furnace throat corresponding to the furnace top roller chamber of the direct fire furnace for passing the strip steel;
• the bottom of the furnace body is provided with a strip steel inlet and a corresponding sealing device and a steering roller;
• the upper part of the furnace body is provided with an upper partition plate with a threading hole to form an upper gas collection chamber for direct fire exhaust gas;
• a secondary combustion chamber for direct fire combustion exhaust gas is provided below the upper gas collection chamber for direct fire exhaust gas, and at least one open flame burner is provided in the secondary combustion chamber for direct fire combustion exhaust gas;
• the lower part of the furnace body is provided with a lower partition plate with a threading hole to form a lower gas collection chamber for direct fire exhaust gas, which connects an exhaust gas fan through an exhaust gas discharge pipeline;
• a plurality of heat exchange and jet bellows units, which are arranged on two sides below the secondary combustion chamber for direct fire combustion exhaust gas in the furnace body along the height direction of the furnace body, wherein a threading channel for passing the strip steel is formed in the middle;
• wherein each heat exchanger and jet bellows unit comprises,
• a bellows body, which is vertically provided with a plurality of heat exchange pipes, wherein the bellows body is provided with a plurality of nozzles on the side opposite to the threading channel;
• wherein an exhaust gas secondary mixing chamber that is communicated with the heat exchange pipe is provided between the bellows bodies that are arranged up and down;
• a circulating fan, wherein an inlet pipeline port is arranged in the threading channel, and an outlet pipeline port is located in the bellows body;
• a plurality of sealing devices that can be passed through by the strip steel are respectively arranged at the upper and lower ports of the threading channel and the threading holes of the upper and lower partition plates.