RU2254579C1 - Fiber-optic measuring instrument of speed and consumption of optically opaque liquids - Google Patents

Abstract

FIELD: the invention refers to measuring technique and may be used for measuring speed and consumption of various liquids including optically opaque for example oil, run-off and technical water, tap water in tubes of large diameter, in an open channel and in seas in extreme conditions.

SUBSTANCE: the arrangement has a submersible sonde which has a body, a shielding window, an oscillator and a photoreceiver located outside of the controlled liquid and a fiber-optic image converter. The input butt-ends of its optical guidewaves form a measuring raster the plane of which is located under an angle to the axis of the flow and output butt-ends are optically connected with the photoreceiver. The output of the photoreceiver is connected with the input of an electronic block. At that the oscillator is optically connected with output even butt-ends of the guidewaves of the converter and the photoreceiver is optically connected with uneven butt-ends of the waveguides.

EFFECT: possibility of using any types of liquids and simplify the construction.

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Description

The device relates to measuring equipment and can be used to measure the speed and flow rate of various liquids, including optically opaque, for example, oil, sewage and industrial water, tap water in pipes of large diameter, in open channels and seas in extreme operating conditions.

Known small-sized laser fluid velocity meter [1]. However, it does not provide a measure of the speed of opaque and contaminated liquids.

Closest to the proposed invention is a fiber optic spot meter with spatial frequency filtering [2]. It consists of a measuring probe placed in a controlled hydrochannel and an electronic unit. The probe is a cylindrical tube with a diameter of 8 mm and a length of 280 mm, at the end of which there is a flow hole with a diameter of 8 mm, in which two spatial frequency filters are installed in the form of a fiber optic array, consisting of two lattices shifted by half the pitch, each of which is formed from the input ends of the seven gradient fibers. The light source is a powerful LED with gradient optics mounted on the outer end of the probe. When the fluid moves, the scattered radiation enters the grating and then through the output ends of the fiber to two photodiodes connected to a differential amplifier. The frequency of the signal at the output of the amplifier is proportional to the flow rate.

In the electronic unit, which is a controller with a fast Fourier transform, this signal is processed and the flow rate is calculated taking into account the diameter of the hydrochannel and the calibration curve.

The disadvantages of the considered device are the impossibility of measuring the flow rate of optically opaque and contaminated liquids, since the measurement takes place at a “clearance”, a certain design complexity, the need for individual calibration, and the inability to work in liquids with a temperature of more than 100 ° C.

The problem to which the invention is directed, is to create a speed and flow meter, characterized by the possibility of reliable operation on virtually any liquid (or gas) under extreme operating conditions, simplicity of design, and also not requiring individual graduation.

The proposed device contains an immersion measuring probe, which includes a housing, a protective window, an emitter, a photodetector and a fiber-optic image converter, the input ends of the optical fibers of which form a measuring raster, and the output ones are optically coupled to a photodetector, the output of which is connected to the input of the electronic unit and characterized in that the emitter is optically coupled to the output even ends of the optical fibers of the converter, and the photodetector is optically coupled to the odd output ends of the optical fibers, at ohm emitter and light detector are located outside the controlled fluid, and measuring the raster plane disposed at an angle to the flow axis.

The essence of the device is illustrated in figure 1 and figure 2.

The device (figure 1) consists of a measuring probe 1, a mounting device 2 and an electronic unit 3. The measuring probe (figure 2) consists of a housing 4, a protective window 5, a fiber-optic converter 6, the input ends of the optical fibers of which are glued together and form a measuring raster 7, the output odd ends of the optical fibers 8 are optically connected through the focal point 9 to the photodetector 10, and the output even ends 8 are optically connected to the emitter 11.

The device operates as follows. The luminous flux of the emitter 11 through the even optical fibers of the fiber-optic converter 6 fall into a controlled environment and are scattered by the microinhomogeneities of the stream. The scattered radiation through the odd ends of the optical fibers 8 and the focon 9 falls on the photodetector 10. When the controlled fluid moves, the frequency of the signal at the output of the photodetector 10 is proportional to the flow velocity and the step of the measuring raster 7.

Then

where V is the flow rate,

F is the output frequency of the photodetector,

d is the diameter of the optical fibers,

K is the calibration factor.

The output signal of the photodetector 10 is processed in the electronic unit 3 in order to obtain information about the speed and flow rate. To reduce the hydraulic resistance of the probe and ensure maximum stability of the calibration coefficient in the required speed range, the planes of the measuring raster and, accordingly, the protective window are located at an angle to the flow axis.

The proposed device is characterized by the possibility of application for various optically transparent and opaque, explosive and aggressive liquids in difficult operating conditions, both in open channels and in large diameter pipes.

The device has been successfully tested at various facilities of Mosvodokanal.

Sources of information

1. Utility model No. 2001122487/20. Small-sized laser speed meter.

2. Kalibrirung des faseroptisches Ortsfilter-Einpunkt-Durchflussgebers. Petrak D., Mahr P. "tm", 2000, 67, No. 11, 474-478 (German).

Claims (1)

A device for measuring the speed and flow rate of optically transparent and opaque liquids, containing an immersion measuring probe, which includes a housing, a protective window, an emitter, a photodetector and a fiber-optic image converter, the input ends of the optical fibers of which form a measuring raster, and the output ones are optically connected to a photodetector, the output of which is connected to the input of the electronic unit, characterized in that the emitter is optically coupled to the output even ends of the optical fibers of the converter, and the photodetector ISRC is optically coupled to the odd output ends of optical fibers; the emitter and photodetector are located outside the controlled fluid; the plane of the measuring raster is located at an angle to the axis of the flow.

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