According to the national standard "code for fire protection design of petrochemical industry > (GB50160-90) regulations," a fixed roof tank B liquid, application of flame arrestor and breather valve. Breather valve and flame arrestor are indispensable safety devices.
It can not only maintain the tank pressure balance, ensure the tank overpressure or vacuum in the rabbit when damaged, and can reduce the volatilization and loss in the tank. The tank pressure breathing valve is to maintain balance, reduce product safety and energy saving medium volatile, often associated with the use of flame arresters. The valve is mainly used for recycling pollution of the environment, endangering personal safety toxic and harmful gases.
1, storage: the above products are shipped to the site, if not installed or after the factory overhaul, rainproof facilities should be stored in a warehouse; emergency vent manhole series products not inverted during transportation.
2, maintenance:
A, the breathing valve series, the staff should be monthly on the tank top check, check valve plate, valve seat, valve stem, valve cover and other parts of any dust, dirt, if any, should be clean dry static; every six months, to the valve sleeve and the valve rod wipe of transformer oil.
B, each half staff should check the fire breathing manhole fire resistant layer at a time, if there is dirt, impurities clogging the fire resistant layer, fire resistant layer should be removed, remove stains with corresponding solvent, then rinse clean dry static fire resistant layer, put in ventilated dry and then put in the shell in.
C, more than the product shell inside and outside the surface of the paint should be re painted every year again.

Shell material: carbon steel, stainless steel (SUS304, SUS304L, SUS316, SUS316L), fluorine, plastic.
Internal core: valve disc, valve seat, valve stem, valve cover.
Internal core material: stainless steel or ptfe.
Sealing ring material: ptfe.
Fire retardant material: stainless steel.
Ambient temperature: -40~+60.

Our company produces the respiration valve, with compact structure, ventilation, small amount of leakage and corrosion resistance, good seal performance, etc., has developed an international advanced level of explosion-proof flame arrester breathing valve (HXF - IZ type), flame arrester is located in the respiration valve at the entrance of suction, put an end to fire into the breathing valve housing. The advantages of small volume, light weight, maintenance, cleaning, convenient replacement, etc.
The valve disc is made of polytetrafluoroethylene, which has the advantages of low temperature resistance and anti-freezing. The valve is equipped with an electrostatic output device to keep the valve at constant potential with the tank.

Operating pressure:
Type A: +355Pa (+36mmH20), -295pa (-30mmh20)
Type B: +980Pa (+100mmH20), -295pa (-30mmh20)
Type C: +1750Pa (+180mmH20), -295pa (-30mmh20)
Type D: special pressure, specified by user.
Explosion-proof level: BS 5501: IIA, IIB, IIC.

DN	20	25	32	40	50	65	80	100	125	150	200
in	3/4	1	11/4	11/2	2	21/2	3	4	5	6	8
L	160	160	160	160	160	213	213	265	306	355	420
H	160	255	255	255	255	260	260	290	330	330	350

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.
Flange standard: GB, HG, SH, HGJ, JB, ANSL, JIS and other standards. (user specified, please specify pressure level)
Manufacturing, testing standards: according to (oil tank breather valve) SY7511-87, (petroleum tank fire arrester performance and test methods) GB5908-86 standards such as manufacturing and acceptance; or user specified standards.