APPARATUS FOR DETERMINING LEAKAGE POINT IN CITY HEAT SUPPLY NETWORK PIPES Russian patent published in 2011 - IPC G01M3/24 F17D5/06 

FIELD: physics.

SUBSTANCE: apparatus for determining a leakage point in city heat supply network pipes is fitted with a +30° phase changer, a -30° phase changer, a +90° phase changer, four multipliers, three low-pass filters and two subtracters. The output of the narrow-band filter is connected in series to the +30° phase changer, the third multiplier, the second input of which is connected to the output of a switch, the second low-pass filter, the first subtracter, the +90° phase changer and the second subtracter, the second input of which is connected to the output of the first low-pass filter, and the output is connected to the input of a decoder. The output of the narrow-band filter is connected in series to a -30° phase changer, the fourth multiplier, the second input of which is connected to the output of a switch, and the third low-pass filter, the output of which is connected to the second input of the first subtracter.

EFFECT: increased noise immunity.

4 dwg