METHOD FOR DETERMINING VOLUMES OF CLOSED CAVITIES Russian patent published in 2019 - IPC G01F17/00 G01F23/00 G01L27/00 G01L23/00 

FIELD: measuring equipment.

SUBSTANCE: invention relates to measurement equipment, in particular to measurements of capacity of closed sealed volumes in various complex systems and installations related to vacuum equipment, with possibility of arrangement of porous materials and / or structural elements therein. In the method of determining the volumes of closed cavities, which are sealed rigid structures, consisting in transferring gas of a known portion from a calibrated container to a measuring one and then carrying out a reverse flow of gas from the measuring container to a calibrated one, at which pressure in measuring container before reverse bypass is maintained equal to pressure in calibrated capacity before direct bypass, evacuating the combined volume consisting of series-connected measured volume, one or more auxiliary volumes and calibrated volume, separated by control valves, in a calibrated volume, a control gas pressure is created at a relatively high pressure of a given value, measured by an absolute pressure transducer, on the basis of the condition that an equilibrium pressure should be established in the combined volume after the gas bypass. Corresponding to conditions of molecular flow mode, created portion of gas is held in calibrated volume with specified exposure, and in parallel with holding auxiliary and measuring volumes are subjected to evacuation, wherein depth of vacuum is determined by a given level of rarefaction, recorded by a wide-range manometric converter; simultaneously with pressure measurements, recording gas temperature in said volumes, before expiration of the exposure period, evacuation of the auxiliary and measuring volumes is simultaneously terminated and at a given moment, the portion is directly bypassed from the calibrated volume into the above volumes, control of pressure and temperature after bypass is performed until linear increase of output signal received from absolute pressure manometric converter with measurement range in relatively low pressure region, then combined evacuation of the combined volume to a value not exceeding a given level of rarefaction, when it reaches pumping of calibrated volume is closed for a time equal to duration of holding interval in a given volume of a portion with pressure of control gas of a predetermined value.

EFFECT: high accuracy and reliability when determining volumes of closed cavities, especially relatively small capacities of arbitrary shape, which are part of complex vacuum systems and plants.

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