Patent ID: 6040777
Filing Date: 2000-03-21
Classification: B01D

Abstract:
A device for determining the exhaustion of an adsorption filter for toxic gases in the ambient air, the device comprising:a gas concentration-measuring device for determining the toxic substance content in the ambient air;a temperature-measuring device for determining the temperature of the ambient air;a memory unit with a first memory field, in which filter data sets associated with adsorption filters are stored, with a second memory field, in which data sets for the toxic substance to be adsorbed are contained, and with a third memory field, which contains preset values for the ambient air humidity and the respiratory minute volume,an input unit for selecting the preset values from at least said first memory field, said second memory field and said third memory field;a timer with a start button, which times a service life t of the adsorption filter;an evaluating circuit, which determines the maximum service life t.sub.max from the selected preset values, the toxic substance content in the ambient air and the temperature of the ambient air and forms a remaining capacity of the adsorption filter from the difference t.sub.max minus t; andan indicator for generating a filter exhaustion indication when the remaining capacity is lower than or equal to a preset limit value.