FIELD: determination of specific surface of dispersive and porous materials. SUBSTANCE: invention refers to determination of specific surface of dispersive and porous materials by method of thermal desorption of gases- adsorbates ( nitrogen or argon ) from flow of mixture of adsorbates with helium at temperature of 77 K. Stationary flow of mixture of helium and adsorbate with specified constant composition is created, surface is aged by heating to temperature of 350-700 K, adsorbate is adsorbed from flow of mentioned mixture at temperature of 77 K, adsorbate is desorbed into flow of mixture by heating to temperature of 200-300 K and concentrations of adsorbate in flow of mixture are measured. At least one continuous flow of helium and at least one continuous flow of adsorbate with specified flow rates are created in addition, one flow of helium as minimum and one flow of adsorbate as minimum are mixed, stationary flow of mixture of helium and adsorbate homogeneous in composition is prepared, composition of mixture is varied discretely within limits of 1 to 50% of adsorbate. Argon or nitrogen are used in the capacity of adsorbate. When nitrogen is used as adsorbate flow of mixture is injected in addition with flow of helium with flow rate twice as large as flow rate of helium used to prepare mixture. General-purpose device including adsorber and detector is supplemented with adsorbate metering pump and two helium metering pumps. First helium metering pump is located ahead of adsorbate metering pump, second helium metering pump is positioned ahead of detector, mixer of flow of first helium metering pump and of flows of adsorbate and mixer of flow of second helium metering pump and flow of mixture. Helium and adsorbate metering pumps are single-channel analogous gas metering pumps or multichannel discrete gas metering pumps. Detector based on distinction of thermal conductivity of nitrogen and helium can be manufactured in the form of Wheatstone bridge incorporating one active arm- measurement cell of diffusion type with constant temperature of sensitive element and three passive arms. One general-purpose device can measure specific surface by all known dynamic single-point and multipoint methods. One bottle of helium and one bottle of adsorbate can be used to feed device with gases. EFFECT: increased efficiency and productivity of procedure and device. 13 cl, 1 dwg, 1 tbl
