The fire breathing breathing manhole, manhole is installed in the tank safety emergency ventilation device on the top, and usually use the fire breathing valve, both to avoid accidental reasoncreated tank sharp overpressure or vacuum, damaged tanks and accidents, and can play the role of the safety flame, is a safety device protection tank in particular, in the material storage vault atmospheric tank cap with nitrogen.

Shell material: carbon steel, stainless steel (SUS304, SUS304L, SUS316, SUS316L), thermal insulation jacket
Internal core components: valve disc, valve seat, valve stem, valve sleeve.
Internal core material: stainless steel or ptfe.
Sealing ring material: ptfe.
Ambient temperature: -30~+60.
Operating pressure: -392Pa (-40mmH2O) ~+1765Pa (180mmH2O).
Explosion proof grade: 5501:IIA IIB, BS, IIC.
Flange standard: GB, HG, SH, HGJ, JB, ANSL, JIS and other standards.

1, with all-weather seal structure instead of edge plane sealing, improve sealing performance.
2, to the suction valve disc weight instead of spring adjustment for the control of opening and closing the suction valve disc, effectively improve the flexibility of open and close the suction valve disc.
3, stainless steel anti fire ripple plate for the fire resistance layer, to prevent the flame through. And a double drawer mouth, shorten the time of cleaning, installation of fire resistance board.

DN	400	450	500	600	650	700	750
in	16	18	20	24	26	28	30
L	370	370	590	720	720	890	890
H	658	658	760	880	880	955	955

The fire breathing valve under normal operating conditions, the fire breathing manhole remained sealed, under normal pressure tank. When the breathing valve work can not meet the accidental reasoncreated tank sharp overpressure, pressure cover is automatically opened breathing manhole, emergency relief, the pressure in the tank to keep normal; when the tank pressure or vacuum rapid decompression when the suction valve opens sharply inhaling atmosphere, maintain normal pressure when the tank; the atmosphere with inhalation sparks, flame, fire resistant layer to "wall effect" to prevent flame through, to protect the safety of the storage tank.