The overpressure blast valve is used as air outlet valve in Civil Defense and military shelters to block out the destructive effects of explosions and to maintain the specified overpressure in the shelter for preventing the entry of toxic agents through the air outlet openings.

Specification

The overpressure blast valve block comprises three closing elements supported by a lever mechanism. Under normal ventilation conditions the lever allows the valve to open when the internal overpressure exceeds 50 Pa. In case of positive or negative blast load from the outside, the closing elements are instantly pushed against the valve seats thus closing the valve. The valve blocks are mounted in structural steel wall frames that can house 1 to 10 blocks. The wall frames are of flush design leaving no parts to extent beyond the concrete wall surface. The valve is completely corrosion resistant. The special aluminum alloy closing elements are epoxy powder coated, all springs are made of stainless steel, and the valve body and wall frame made of structural steel are hot dip galvanized.

The overpressure blast valve is made in compliance with all known UK, NATO and international security and performance standards.

The valve is designed and tested to withstand multiple long duration (positive phase duration ? 70 ms) blast loads having peak reflected overpressure of 10 bar while retaining its full functional ability.

Pass through (leakage) pressure and impulse of the valve do not exceed the values of 0.60 bar and 0.65 bar ms respectively as measured on the average tributary wall area occupied by the valve.

The valve is designed to function within the operating temperature range of -20 …+200?C.