RU137373U1 - REMOTE METHANE SENSOR - Google Patents

Abstract

1. A remote methane sensor containing a laser diode emitting light at a wavelength corresponding to the absorption band of methane, an optical detector that receives and measures part of the laser radiation back-reflected from a distant target and transmitted through a cloud of detectable gas; a signal processing board connected to an optical detector, a processor module connected to a signal processing board, characterized in that it further comprises a transmitting lens with a mirror system connected to a fiber optic divider that is connected to the laser diode using an optical fiber, a receiving lens collecting signal reflected back from a distant target and passed through a cloud of detected gas, and a focusing signal to the receiving platform of the optical detector, a multi-pass cell the other part of the laser radiation, separated by a fiber optic divider and introduced by the collimator into the multipass cell, and then received by the second optical detector, the collimator and the second optical detector are mounted on opposite sides of the multipass cell, and the pump is installed at the output of the multipass cell, simultaneously swinging through it for due to the created vacuum, detectable gas coming from a sampler located at the inlet of a multi-pass cell. 2. The remote methane sensor according to claim 1, characterized in that the part of the laser radiation directed to the transmitting lens with a system of mirrors is from 90 to 98%. The remote methane sensor according to claim 1, characterized in that the part of the laser radiation guided by means of

Description

Technical field

The utility model relates to the field of measurement technology, and is designed to remotely determine the excess concentration of methane against the background of the natural level of methane in the atmosphere using lidar technology (laser absorption spectroscopy), namely, a remote methane sensor based on lidar technology.

State of the art

Thousands of pumping stations with tens of thousands of installed compressors are engaged in providing natural gas to enterprises. To maintain the safety and integrity of this huge system and to comply with all regulatory requirements, regular inspections of gas pipelines are required to detect leaks. Regular periodic inspections for leaks, as a rule, are carried out using walking walks, mobile aerial photography, etc.

Known systems for inspecting pipelines for methane leakage, for example, flammable gas indicators operating on the principle of catalytic combustion of the detected gas [http: //gastechno.rf/category/gazovoe-oborudovanie/gazoanalizatori/sistemi-kontrolja-zagazovannosti-i] or flame ionization detectors operating on the principle of measuring the electrical conductivity of a flame [http://chromatography.narod.ru/lecture/detection.html]. Known devices operate with an open flame placed inside the device, which is not safe. In addition, these devices have low sensitivity, the sampler must be located as close as possible to the leak.

Known portable natural gas leak detector [US 7710568, 2010], containing a laser light source; Multipass optical cell with a fixed optical path length. According to the invention described in US Pat. No. 7,710,568, the detected gas is pumped through the cell using a pump; At the end of the cell, a detector is installed at the output of the optical path, into which the laser beam that previously passed through the cell enters. The detector is connected to the signal processing board. Concentration data is displayed. A hard (possibly telescopic) probe is used to take air samples near the ground.

A disadvantage of the known detector is that the probe for sampling must be brought as close as possible (close) to the place of gas leakage. This is not always convenient and feasible, since the leak may be located, for example, behind the fence, that is, it is difficult to access.

The prior art device for remote laser detection of methane leakage at a level exceeding the natural background level using absorption laser spectroscopy based on tunable wavelength diode laser [US 7075653, 2006]. The device described in US patent 7075653, consists of a laser capable of emitting light at a wavelength corresponding to the absorption band of methane; an optical detector capable of receiving and measuring a portion of said laser radiation back-reflected from a remote target and transmitted through a cloud of detectable gas; a signal processing module coupled to the detector; a statistical detection processor module operably connected to said detector capable of calculating an estimate of the level of natural background of methane, an estimate of the noise level of the measurements, distinguishing which of the indicated levels exceeds the permissible alarm limits; a user interface operatively coupled to said processor module. The device is arranged in two parts, including a hand gun and a shoulder bag, connected by a functional cable.

A disadvantage of the known device is the low accuracy of localization of the leak.

The device for remote laser methane leak detection described in US Pat. No. 7,075,653 is adopted as the closest analogue of the proposed technical solution.

Utility Model Disclosure

The present utility model is based on solving a problem aimed at creating a device capable of remotely determining a methane concentration at a leak site with increased localization accuracy of a methane leak site.

The technical result, which can be obtained using the proposed technical solution, is to increase the accuracy of localization of the methane leakage site while remotely determining the methane concentration at the leakage site.

The problem is solved, and the technical result is achieved by the fact that the remote methane sensor containing a laser diode (1) emitting light at a wavelength corresponding to the methane absorption band, an optical detector (8) capable of receiving and measuring part of the laser radiation reflected back from the remote target and detected gas passing through the cloud; a signal processing board (14) connected to an optical detector (8), a processor module (15) connected to a signal processing board (14), characterized in that it further comprises a transmitting lens (4) with a mirror system (5) connected to fiber optic divider (3), which is connected to a laser diode (1) using an optical fiber (2), a receiving lens (7) that collects the signal reflected back from the remote target and passed through the cloud of the detected gas, and the focusing signal to the receiving platform of the optical detector (8), multi a transition cell (10) that transmits another part of the laser radiation, separated by a fiber optic divider (3) and introduced by the collimator (9) into the multipass cell (10), and then received by the second optical detector (11); wherein the collimator (9) and the second optical detector (11) are mounted on diagonally opposite parts of the multipass cell (10); and a pump (13) is installed at the outlet of the multi-pass cell (10), which simultaneously swings through it due to the created vacuum the detected gas coming from the sampler (12) located at the inlet of the multi-pass cell (10).

In an additional aspect, the remote methane sensor is characterized in that a part of the laser radiation directed into the transmitting lens (4) with the mirror system (5) is from 90 to 98%.

In yet another additional aspect, the remote methane sensor is characterized in that the part of the laser radiation directed by the fiber optic splitter (3) and collimator (9) into the multipass cell (10) and then received by the second optical detector (11) is from 2 to 10%.

In yet a further aspect, the remote methane sensor is characterized in that the processor module comprises an LCD screen.

In another additional aspect, the remote methane sensor is characterized in that the laser diode, optical fiber, fiber optic divider, signal processing board, processor module with an LCD screen, a collimator, a multi-pass cell, a second optical detector, and a suction pump are located in one housing made in in the form of a hand gun.

In yet another aspect, the remote methane sensor is characterized in that a sampler with an inlet filter is located in the sample probe.

In yet a further aspect, the remote methane sensor is characterized in that the transmitting lens, the mirror system, the receiving lens, and the optical detector comprise separate optical parts for detecting methane leaks.

Brief Description of the Drawing

The essence of the proposed technical solution is illustrated by a figure. The Figure shows a structural diagram of the proposed remote methane detector.

The proposed remote methane detector (see. Fig.), Contains a laser diode (1) with the ability to quickly rebuild along the wavelength, an optical fiber (2) for transporting laser radiation, an optical fiber divider (3), a transmitting lens (4), a mirror system ( 5), topographic targets (6), receiving lens (7), optical detector (8), collimator (9), multipass cell (10), optical detector (11), sampler (12), with inlet filter, suction pump ( 13), a signal processing board (14), a processor module (15) with an LCD screen.

It is important to note that the proposed technical solution improves the accuracy of localization of the methane leak site when remotely determining the methane concentration at the leak site by introducing an optical fiber divider (3), a collimator (9), a multipass cell (10), and a second optical detector (11 ), a sampler (12) and a pump (13), which are connected according to the circuit shown in FIG.

Since laser radiation is divided into two parts by an optical fiber divider (3). In this case, one of the parts of the laser radiation (large), directed through the transmitting lens (4) with the mirror system (5), makes up from 90 to 98% of the radiation. The other part of the laser radiation (smaller), directed by a fiber optic splitter (3) and a collimator (9) into a multipass cell (10), and then received by the second optical detector (11), accounts for from 2 to 10% of the radiation. This allows the lineman to simultaneously remotely determine not only the concentration of methane at the site of the leak, but also accurately indicate the location of the leak.

Utility Model Implementation

Remote methane detector, shown in Fig., Operates as follows. The laser diode (1) emits light at a wavelength corresponding to the absorption band of methane. The radiation is transported through the optical fiber (2) to the fiber optic splitter (3), after which most of the radiation is transmitted to the transmitting lens (4) and through the mirrors (5) enters the atmosphere. The laser beam is directed by the operator to possible locations for detecting methane leaks. Part of the radiation reflected back from the topographic targets (6) is collected by the receiving lens (7) and focused on the receiving platform of the optical detector (8). The optical detector (8) converts the optical signal into an electrical signal, and transmits it to the signal processing board (14). A smaller part of the radiation after the fiber optic splitter (3) is fed through the fiber into the collimator (9). Open laser radiation emerges from the collimator (9), which enters the multipass cell (10) with a fixed optical path. An optical detector (11) is installed at the output of the optical path of the cell (10). A sampler (12) (possibly rigid, telescopic) with an input filter mounted at the end is connected to the cell (10) using a flexible tube. Detection gas is sucked through this filter due to the vacuum generated by the suction pump (13) installed at the outlet of the multi-pass cell (10), this pump is pumped through the cell. An optical detector (11) registers an optical signal and converts it into an electrical signal. The optical detector (11) is also connected via electrical wires to the signal processing board (14). The processed signals are sent to the processor module (15) for subsequent processing, the processing results are displayed on the LCD screen as the level of methane concentration in ppm.

Structurally, in a remote methane sensor, such elements as a laser diode, optical fiber, fiber optic divider, signal processing board, processor module with LCD screen, collimator, multipass cell, a second optical detector, and a suction pump can be located in one housing made in the form of a manual the gun. In addition, structurally, a sampler with an inlet filter can be located in the sampling probe.

Claims (7)

1. A remote methane sensor containing a laser diode emitting light at a wavelength corresponding to the absorption band of methane, an optical detector that receives and measures part of the laser radiation back-reflected from a distant target and transmitted through a cloud of detectable gas; a signal processing board connected to an optical detector, a processor module connected to a signal processing board, characterized in that it further comprises a transmitting lens with a mirror system connected to a fiber optic divider that is connected to the laser diode using an optical fiber, a receiving lens collecting signal reflected back from a distant target and passed through a cloud of detected gas, and a focusing signal to the receiving platform of the optical detector, a multi-pass cell the other part of the laser radiation, separated by a fiber optic splitter and introduced by the collimator into the multipass cell, and then received by the second optical detector, the collimator and the second optical detector are mounted on opposite sides of the multipass cell, and the pump is installed at the output of the multipass cell, simultaneously swinging through it for due to the created vacuum, detectable gas coming from a sampler located at the inlet of a multi-pass cell. 2. The remote methane sensor according to claim 1, characterized in that the part of the laser radiation directed to the transmitting lens with a system of mirrors is from 90 to 98%. 3. The remote methane sensor according to claim 1, characterized in that the part of the laser radiation directed by a fiber optic divider and a collimator into a multipass cell and then received by the second optical detector is from 2 to 10%. 4. The remote methane sensor according to claim 1, characterized in that the processor module contains an LCD screen. 5. Remote methane sensor according to claims 1 to 4, characterized in that the laser diode, optical fiber, fiber optic divider, signal processing board, processor module with LCD screen, collimator, multipass cell, second optical detector, suction pump are located in one case made in the form of a hand gun. 6. The remote methane sensor according to claims 1 to 4, characterized in that the sampler with an inlet filter is located in the sampling probe. 7. The remote methane sensor according to claims 1 to 4, characterized in that the transmitting lens, mirror system, receiving lens, and optical detector comprise separate optical parts for detecting methane leaks.

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