30.2. Calculation of a damper curtain

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For premises with explosive production facilities, spark-proof fans must be used, and the temperature of the coolant for the heaters through which the recirculated air passes must not exceed 80% of the autoignition temperature of gases, vapors or dust. If hot water is used as a coolant, its temperature for production categories A, B, and E in the presence of flammable and explosive dust in the premises must not exceed 1100 C, and in its absence, not exceed 1500 C. In the absence of appropriate spark-proof equipment, the curtain in premises with categories A, B and E may be allowed to take outside air or air from adjacent premises of categories B, G and D, if there is no flammable dust in it.

The automation means of air curtains must ensure: starting poland mobile database fan when the serviced opening opens and when the temperature near the closed opening drops below the set value; switching off the fan after the serviced opening closes and when the air temperature near the closed opening returns to the set value.


The total air flow rate supplied by a damper curtain is determined by the formula

, (30.1)

where is the curtain characteristic – the ratio of the air flow rate supplied by the curtain to the air flow rate passing into the room through the opening when the curtain is operating; is the opening flow rate coefficient when the curtain is operating (taken as a function of and ) ; Fpr is the area of ​​the opening equipped with a curtain, m2; is the difference in air pressure on both sides of the outer enclosure at the opening level, Pa; is the density, kg/m3, of the mixture of air supplied by the curtain and outside air at a temperature tcm equal to the standard.

The pressure difference is determined by calculation as a result of solving the air balance equations taking into account the wind pressure for the cold season of the year.