RU2625234C1 - Device for selecting air samples in engine nacelles of aircraft gas turbine engines - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: device comprises a cylindrical sampler housing with a risk-loaded rod and a rubber-sealed piston located inside, a handle attached to the rod for manual piston movement and a lid covering the over-piston space. The sampler housing is made with an inlet nozzle, to which a solenoid valve is attached by a pipeline, connected with the control panel. Between the lid and the housing of the sampler there is an annular rubber seal of smaller diameter, on which a lid with a side spring-loaded latch and stuffing box are screwed. An annular rubber gasket is attached to the inner end surface of the sampler lid, within the circumference of which on the lid there is a through hole with a closing shut-off valve. The stuffing box seal sealing the gap between the rod and the sampler lid is designed to seal the over-piston space when the rod is moved. The lid is provided with a side spring-loaded rod latch to maintain the vacuum until the sample is collected and stored under excess pressure after it has been withdrawn. The lateral surface of the rod is made with ruler graduations extending beyond the lid.

EFFECT: increased accuracy of determining fire extinguishing concentrations in the air of the engine nacelles of aircraft gas turbine engines by preventing dilution of the sample with air before and after its collection, and reduced time of the ground and flight experiment to assess the fire resistance of the engines.

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Description

The invention relates to a technique for sampling air of engine nacelles of aircraft engines (LA) to study the vapor content of fire extinguishing agents (freons, carbon dioxide, SF6 and others) in the air of a nacelle when a fire extinguishing system is triggered and to improve the accuracy of their determination.

When the engine fire extinguishing system is triggered on an aircraft, a certain amount of a fire extinguishing agent such as freon and others is injected into the engine nacelle. The regulatory documents determine the sufficiency for fire extinguishing of the concentration of these substances in the engine nacelle over time depending on the type of extinguishing agent.

The proposed device can be used in factory and certification tests of aircraft for compliance with the requirements of §1195 AP-25 (Aviation Rules. Part 25. Airworthiness standards of transport aircraft. 2008), similar to AP-29 (helicopters) and AP-23 ( civilian light aircraft).

Known devices for sampling and storing air samples in the form of glass non-calibrated gas pipettes with two single-pass valves, made in accordance with GOST 18954-73 "Glass apparatus and pipettes for sampling and storage of gas samples."

Similar devices are made in the form of canisters described in ASTM (2001): “Standard Test Method for Determination of Volatile Organic Chemicals in Atmospheres (Canister Sampling Methodology), West Conshohocken, PA, American Society for Testing and Materials (ASTM Standard D5466-01 ) ". In this case, a canister with a shut-off valve is used either pre-evacuated, or the selection is made by gas exchange (purging the canister with a large amount of air). The last option for fire extinguishing tests is not suitable, since gas exchange requires a long selection (regulatory documents establish restrictions on the time of selection). Typically, in tests to test a fire extinguishing system, metal evacuated containers with electromagnetic valves are used, assembled several in containers. Such devices are described in departmental methodology No. 12-16-III, developed by OJSC “LII them. M.M. Gromova. " To date, it is these structures that are used in appropriate tests. However, these devices have a significant drawback. Tanks are evacuated under laboratory conditions in the ground and the vacuum after installing them in the nacelle is not controlled. For various reasons, quite a lot of time elapses before the start of testing (sometimes several days). Vacuum control immediately before the flight (ground race), as a rule, is impossible, as this requires complex installation work. Meanwhile, practice has shown that unpredictable air leakage into these containers is quite possible, which leads to distortion (underestimation) of the results of a subsequent analysis of the content of fire extinguishing agent in them. Such errors lengthen the costly testing of aircraft.

The closest in technical essence to the proposed device is a manual pump-sampler, RU patent number 89701, publ. 12/10/2009. The trade name is NP-3M (hereinafter referred to as NP-3M), intended for the collection of single samples of gas-air mixtures for the subsequent determination of their chemical composition using indicator tubes in accordance with GOST P 51712-2001, GOST 12.1.014 -84, GOST P 51945-2002. The manual NP-3M sampler pump is an original development of Crismas + CJSC and is produced according to KRMF.418311.002TU.

This device, selected as a prototype, contains: a cylindrical body, a rod with risks and a handle, a piston with a rubber seal, a cover covering the over-piston space. However, the disadvantages of this design include the fact that the pump does not have a locking device and the vacuum created by it is not intended for long-term preservation due to the significant leakage of air through the piston seal.

The technical result, which is achieved by the claimed device, is to increase the accuracy of determining fire extinguishing concentrations in the air of engine nacelles of aircraft gas turbine engines by preventing dilution of the sample with air before and after sampling, and, consequently, reducing the time of the ground and flight experiment to evaluate the fire protection of engines.

To achieve a technical result in the device for sampling air in the nacelles of aircraft gas turbine engines, comprising a cylindrical body of the sampler with a risk stem located inside the piston and a rubber seal, a handle attached to the rod for manual movement of the piston and a cover covering the over-piston space, the housing the sampler is made with an inlet pipe to which a solenoid valve connected to the control panel is connected by a pipeline. An annular rubber seal of smaller diameter is mounted between the lid and the body of the sampler, onto which the lid is screwed on with a lateral spring-loaded latch and an oil seal. An annular rubber gasket is attached to the inner end surface of the sampler lid, inside the circumference of which there is a through hole with a closing shut-off valve on the lid. In this case, the stuffing box seal, which seals the gap between the stem and the sampler cover, is made with the possibility of sealing the over-piston space when moving the rod, the cover is made with a lateral spring-loaded rod clamp to preserve the sample under overpressure, the side surface of the rod is made with the divisions of the ruler beyond the cover.

In FIG. 1 shows a longitudinal section of a device for sampling air in the nacelles of aircraft gas turbine engines.

The proposed device (Fig. 1) contains a cylindrical housing 1 with an inlet pipe 2 to which a solenoid valve (EMC) 4 is connected by a pipe 3, a piston 5 with an annular rubber seal 6 moves inside the housing, the rod 7 with risks 8 and a ruler 9 is attached to the piston and ends with a handle 10, a cover 12 with a lateral spring-loaded latch 13 and an oil seal 14 is screwed onto the housing with an annular rubber seal 11, an annular rubber gasket 15 is attached to the inner end surface of the lid, inside of which the cover has a through hole 16 with a shut-off valve 17. Solenoid valves are opened by applying a voltage through the wires 18, 19 with external control.

The device operates as follows.

They prepare the sampler for work, create a vacuum inside the cylindrical body 1 of the sampler. For this, the inlet pipe 2 is connected through a pipe 3 to a closed solenoid valve (EMC) 4, and inside the cylindrical body 1 of the sampler it moves through a gland 14 of the rod 7 with the piston 5 and the ring rubber seal 6, if the latch 13 of the cover 12 does not fall into one of the pictures 8. The fixation is removed by rotation of the rod by the handle 10. At the same time, air from the over-piston space leaves through the hole in the cover 16 and the open shut-off valve 17. With the rod fully extended, which corresponds to mark 100 on the line 9, the piston abuts the ring rubber gasket 15. This position (cocking) is fixed by getting the latch 13 of the cover 12 in the extreme left risk 8 and corresponds to a complete vacuum. In this state, the samplers (the number of samples is determined by the test program) are delivered to the facility several hours before the start of the tests to check the fire extinguishing systems.

Immediately before the start of the test, all the samplers are removed from the clamps by a circular rotation of the rod handle and are retracted with light pressure until a weak stop. If it is possible to retract the rod to 0 line division, then this corresponds to 100% preservation of vacuum and such a sampler can participate in further tests. If the stem cannot be retracted by less than 5 divisions out of 100 (vacuum is less than 95% of the initial one), then such a sampler is rejected and is not involved in further tests (disassembly and repair of seals - if time permits, then before the start of the test). Samplers that have passed vacuum control are re-cocked and placed in the engine nacelle according to the test program. EMC 4 wires 18 are connected to the control panel 19 with a voltage source. During the tests, after the fire extinguishing system is triggered when voltage is applied to the corresponding valves 4, they open and air samples of the engine nacelle are taken. After testing, the samplers are dismantled. Each sampler is removed from the clamp and the rod handle is pushed into the body until it stops to create some excess pressure of the sample taken. This position is fixed by hitting the tip of the latch retainer in one of the nearest pictures 8 of the rod 7. The shut-off valve 17 on the lid closes for additional preservation of the sample. To enter the sample into the analyzer, for example, into the loop of the metering valve of a gas chromatograph, no intermediate devices are needed that increase the error. In laboratory conditions, the shut-off valve 7 on the cover 13 opens, and the output of the EMC 4 is connected to the input of the metering device. It opens by applying voltage to the EMC and, since the gas in the sampler is under pressure, it enters the dispenser. For control at the outlet of the dispenser, a tube is usually mounted dipped in water. The appearance of gas bubbles in it indicates the supply of a sample to the dispenser. If the pressure is not enough, then the sampler rod is removed from the clamp and with a light pressure on the handle the air sample is squeezed into the dispenser. This procedure can be done repeatedly, because the volume of the dispenser loop is usually about 1 ml, and the capacity of the sampler, depending on the overall dimensions, can be from 100 to 500 ml.

Thus, by analyzing parallel samples, the accuracy of the analysis of the gas mixture can be further improved.

A device for sampling air in the nacelles of aircraft gas turbine engines provides representative sampling due to the long-lasting and controlled vacuum prior to sampling due to the use of an electromagnetic valve and additional sealing of the nadporshny sample space prior to sampling and for a long time saves the sample without dilution by keeping it under overpressure and isolation of the nadporshnego space from the atmosphere with an annular rubber seal, shut-off valve and oil seal com.

Claims (1)

A device for sampling air in the nacelles of aircraft gas turbine engines, comprising a cylindrical body of the sampler with a risk stem located inside and a piston with a rubber seal, a handle attached to the rod for manually moving the piston and a cover covering the over-piston space, characterized in that the sampler body made with an inlet pipe, to which a solenoid valve connected to the control panel is connected by a pipe, is installed between the cover and the body of the sampler a smaller diameter ring rubber seal was inserted onto which the cap with a lateral spring-loaded lock and gland is screwed on, a ring rubber gasket is attached to the inner end surface of the sampler cap, inside of which there is a through hole on the cap with a closing shut-off valve, while the packing gland sealing the gap between the stem and the cover of the sampler, made with the possibility of sealing the piston space when moving the rod, the cover is made on with a lateral spring-loaded rod clamp to maintain a vacuum until the moment of sampling and preservation of the sample under overpressure after sampling, the lateral surface of the rod is made with divisions of the ruler that extends beyond the cover.

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