METHOD FOR DETERMINING THE CONCENTRATION OF FIRE EXTINGUISHING AGENTS IN THE AIR OF ENGINE NACELLES OF GAS TURBINE ENGINES AND A DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2022 - IPC G01N1/22 

FIELD: chemical analysis.

SUBSTANCE: inventions relate to the technology for analyzing the air of engine nacelles of aircraft engines to study the sufficiency of the vapor content of extinguishing agents (refrigerants, carbon dioxide, electronegative gas and others) in the air of the nacelle when the fire extinguishing system is triggered and to increase the accuracy of their determination. A method for determining the concentration of extinguishing agents in the air of a gas turbine engine nacelle (GTE) involves alternately pumping air pre-selected in sealed samplers into a calibrated container (a syringe of fire extinguishing substances with the air of the engine nacelle of the GTE), determination of the actual concentrations of fire extinguishing substances, while the measuring unit in the form of a syringe with a measuring glass container, with a protruding contact on the rod, is placed vertically in a water bath container, thermostatically controlled above the boiling point of the fire extinguishing substance and not below the room temperature of the holder. A thermostatically controlled capillary is connected to the syringe, selected so that at a load pressure of 500 g per syringe stem, its complete emptying with air without a capillary occurs in 2-3 seconds, and with a capillary connected in 30-50 seconds. Then the emptying of a given volume of a container with different concentrations of fire extinguishing agents is carried out between the first and second marks of a given volume in a cylindrical container: from the beginning of passing the control sample to the second mark of emptying the given volume. In this case, the contact on the rod turns on the timer through the upper switch and, after passing the second mark, turns off the timer through the lower switch. The time of emptying of the given volume is fixed, the time of passing control sample volumes is determined, then after analyzing all samples of air mixtures with a known concentration of a fire extinguishing agent control sample and based on the results obtained, a calibration graph is built according to the dependence of the time of emptying of the given volume of the syringe on the concentration of the control sample, comparing the time data for the studied air samples of the engine nacelle with the calibration curve, the values of the concentration of the extinguishing agent in them are used in the certification of the aircraft, at the same time, the operation of the upper timer switch counting the emptying time occurs after emptying 40% of the calibrated container to establish a constant pressure in it at the level of 0.5-0.7 kg/cm, which ensures reproducibility of the analysis results. A device for determining the concentration of extinguishing agents in the air of a gas turbine engine nacelle is studied, including a calibrated cylindrical tank and an air duct for connection to the selected sample, it is made of glass with volume markings, has upper and lower covers. An additional air vent hole is made in the upper cover, and in the lower cover, there is a cone with an external wedge clip for connecting and holding a capillary with a cannula, thermostatically controlled together with a container in a water bath with a temperature controlled by a sensor with a thermoswitch and heated by an electric heating element to avoid condensation of the measured substance in the capillary, which is part of a tripod stand. In the slot of the cover, made in the form of a cylinder with an additional slot for moving the capillary plug with a holder, this container is vertically installed with a piston with a rod freely moving in it, the upper platform of which is made in the form of a disk with sides, which is a holder for a weight piece, under the pressure of which the piston moves. At the same time, a protruding contact is made on the rod, which alternately turns on the upper and lower switches connected to a timer device that fixes the time, located on a rod made parallel to the rod to count the time of emptying the calibrated container, and the base of the tripod is made in the form of a tripod with adjusting screws that ensure the verticality of the calibrated container according to the reading of the level located on the upper the lid of the bath, which makes it possible to obtain reproducibility of the graduations, and consequently, the results of the analysis.

EFFECT: invention provides an increase in the reliability of the assessment of the concentration of fire extinguishing agents in the gas turbine engine nacelles due to the use of evacuated samplers.

2 cl, 1 dwg