1. Brief introduction of product:
All-weather antifreezing breathing valve, also known as all-weather (fireproofing) antifreezing breather valve, is mainly used for the cold season or cold area of crude oil, gasoline, kerosene, light diesel oil, aromatics and other fixed roof storage tank, the breathing valve equipment for antifreezing insulation treatment, to prevent the failure of valve caused by freezing weather, leading to respiratory valve failure, protection of storage tanks at the damage from overpressure or vacuum effect, while preventing the evaporation loss of oil, usually with the fire facilities.

2. Characteristics of product:
2.1 All-weather antifreezing breather valve has a large amount of ventilation, a small amount of leakage, corrosion resistance and other characteristics and has the electrostatic grounding wire, so that the valve body and keep such potential. The breathing valve products are comply with SY/T0511-1996 standards.
2.2 The range of operated pressure:
positive pressure: 353Pa(36mmH2O) 980Pa(100mmH2O) +1765pa（180 mmH2O）
negative pressure: 295Pa(30mmH2O)

2.3. There are three operated pressure: A,B and C for breather valve:
A：-295pa—+355pa

B：-295pa—+980pa

C：-295pa—+1765pa

3. Technical parameters: