RU2120111C1 - Flowmeter - Google Patents

Abstract

FIELD: instrumentation engineering. SUBSTANCE: flowmeter has two resonators positioned along pipeline, on external side of the latter. Each resonator has flexible wall in common with pipeline. It also includes units connected to each resonator for generation of electromagnetic oscillations in resonator and recording of resonant frequency of resonator electromagnetic oscillations. These units are connected with their outputs to inputs of comparison units of resonator resonant frequencies. Each resonator is made as U-shaped waveguide. Its second end wall is also flexible and common with pipeline wall. It is positioned in the same transverse section of pipeline. EFFECT: enhanced sensitivity. 2 dwg

Description

 The invention relates to the field of measurement technology and can be used to measure the flow of substances transported through pipelines.

 A non-contact flow meter is known, comprising two volume resonators mounted outside the pipeline in different sections along its length (US Pat. No. 3,939,406). Each of these resonators has a common elastic end wall (membrane, diaphragm, etc.) with the pipeline, as well as blocks connected to each resonator for generating electromagnetic oscillations in the resonator and registering its resonant frequency and a unit for comparing the resonant frequencies of these resonators. The output signal of the comparison unit corresponds to the measured flow. To increase the sensitivity, the distance between the resonators along the pipeline must be increased, which is often not possible. So, when using this device to determine the liquid sodium velocity in the pipeline, equal to ~ 1.8 m / s (minimum value) from the pressure drop, the distance between the resonators should be ~ 3 m. With a shorter distance, the sensitivity of the device is not high enough.

 The objective of the claimed technical solution is to increase the sensitivity of the device to the measured flow.

 The solution to this problem is achieved by the fact that in a flow meter containing two pressure sensors that are located along the length of the pipe from the outside in two sections, each of the sensors is made in the form of a microwave waveguide resonator having a first elastic end wall in common with the pipe, each waveguide resonator is connected with the corresponding unit for generating electromagnetic waves and registering the resonant frequency of electromagnetic waves, and a unit for comparing resonant frequencies with two inputs, sub li ne respectively to the outputs of said two blocks generation of electromagnetic oscillations and registration of resonance frequencies of electromagnetic waves and an output indicator coupled to each waveguide resonator is made U-shaped and the second elastic end wall, as is common with the conduit wall.

 The essence of the invention, characterized by a combination of the above features, is that an increase in sensitivity to the measured flow rate is achieved.

 The salient features in the aforementioned aggregate are the design of each resonator in the form of a U-shaped waveguide resonator, the execution of each end wall of each U-shaped resonator is also elastic, the presence of such a second elastic end wall in common with the pipeline wall, the location of both end walls of each waveguide resonator in the same corresponding cross section. The combination of these distinctive features determines a new property of the proposed flowmeter: it is possible to perceive a useful signal simultaneously by both end walls of each waveguide resonator. This property provides a useful technical result - increased sensitivity to the measured parameter.

 The invention is illustrated by drawings. In FIG. 1 is a functional diagram of a device with a schematic representation of resonators and a pipeline. In FIG. 2a and FIG. 2b is a cross section of a pipeline and a waveguide resonator located on its outer side with elastic end walls, which are respectively at a certain distance (a) and in close proximity to each other (b).

 The device (Fig. 1) contains waveguide resonators 1 and 2 with both end walls in each of them 3 and 4, respectively, common with pipeline 5, blocks for generating electromagnetic waves and recording resonant frequencies 6 and 7, a unit for comparing resonant frequencies 8, indicator 9 In FIG. 2a and FIG. 2b, the designations are indicated for one of the waveguide resonators 1, for the second resonator 2, these drawings are similar.

 The device operates as follows. In resonators 1 and 2, with the help of blocks 6 and 7, respectively, they excite electromagnetic oscillations at frequencies corresponding to the resonant (natural) frequencies of these resonators. In the same blocks, the resonance frequencies of the resonators 1 and 2 are determined. Next, in the resonance frequency comparison unit 8, the measured frequencies are converted to values corresponding to the pressure inside the pipe 5 in the region of the first and second resonators, and the pressure drop is functionally related to the flow rate of the substance . In the device, the end diaphragms of each resonator, for example, resonator 1 with end walls 3 (see Fig. 2), can be located in the same cross section or at some distance (Fig. 2, a) from each other, in particular diametrically opposite, or next to each other (Fig. 2, b). Each waveguide resonator has a U-shape.

 The same pressure in the area of each resonator in this device can be measured at half the magnitude of the deflection of each diaphragm than in the resonators of the prototype device. On the other hand, this means that when using the same designs of elastic end walls, such a flow meter allows you to measure twice the pressure in each area of the installation of the resonator. This allows us not to present, firstly, such stringent requirements for the parameters of the resonators (size and material of the diaphragms) compared with similar requirements in the prototype device. Secondly, this makes it possible to expand the measurement range due to the possibility of measuring large flows, since the deflections of the elastic walls by the same amount as before, now correspond to the high flow rates of the substance in the pipeline. An increase in the sensitivity of pressure perception by resonators also makes it possible to reduce the distance between the resonators, since a decrease in pressure drop causes larger than before (in the prototype) changes in the resonant frequencies of the resonators. That is, the same as previously a change in the resonant frequencies corresponds to a reduced pressure in the region of the resonators.

 Thus, in this flowmeter, due to the organization of obtaining useful information using two U-shaped waveguide resonators with two elastic end walls in each of them, a technical result is achieved - an increase (twice) in sensitivity. Such a flow meter is applicable for determining the flow rate of various substances transported through various pipelines, without introducing any device elements into the pipeline.

Claims (1)

 A flowmeter containing two pressure sensors that are located along the length of the pipeline from the outside in two sections, each of the sensors is made in the form of a microwave waveguide resonator having a first elastic end wall in common with the pipeline, each waveguide resonator is connected to a corresponding electromagnetic oscillation generation and registration unit resonant frequency of electromagnetic waves, a unit for comparing resonant frequencies, having two inputs connected respectively to the outputs of these Vuh blocks generation of electromagnetic oscillations and registration of resonance frequencies of electromagnetic waves, and an output coupled to an indicator, characterized in that each waveguide resonator is made U-shaped and the second elastic end wall, as is common with the conduit wall.

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