RU35428U1 - Device for measuring fluid flow - Google Patents

Description

Device for measuring fluid flow

The utility model relates to flow measuring equipment and can be used to measure the flow of fluids in pipelines.

A device for measuring the speed (flow rate) of a fluid stream 1, consisting of a streamlined body mounted on the end of the connecting rod, which is placed in a protective tube. The other end of the connecting rod is fixed in the meter body. A device for measuring the velocity (flow rate) of a fluid flow 1 measures the flow velocity by converting the fluid velocity into a force measured by strain gauges mounted on a connecting rod.

The disadvantage of this device for measuring the speed (flow rate) of a liquid flow is the dependence of the measurement results on temperature. In addition, a device for measuring the velocity (flow) of a fluid flow cannot be used to measure mass flow without significant structural improvements.

A number of other devices are also known that implement the measurement of the velocity (flow rate) of a fluid (gas) flow with a flow of fluid onto a sensitive elastic element, the movement of which is used to judge the flow rate (flow rate) of 2-4. The main disadvantage of these devices is their limited functionality, namely the impossibility of measuring mass flow.

The closest technical solution (prototype) to the claimed device is a device 5 for measuring the flow of liquids and gases, containing a measuring section of the pipeline,

pm

a sensitive element in the form of an elastic elastic ferromagnetic plate pulled together by springs in the longitudinal direction and an induction sensor. The device measures the frequency of deformation of the elastic plate proportional to the flow rate from the incoming flow of liquid (gas).

A disadvantage of the known technical solution of the device for measuring the flow of liquid (gas) in the pipeline is also its limited functionality, otherwise the impossibility of measuring the mass flow. In addition, the accuracy of the flow measurement is greatly affected by the temperature of the fluid.

Thus, the purpose of the claimed object (otherwise, the required technical result) is to provide the well-known technical solution of higher consumer properties by expanding the functionality, namely, providing measurement of the mass flow rate of the fluid in the pipeline.

The required technical result in the inventive device is achieved by the fact that according to the prototype device, it contains a measuring section of the pipeline with two cross sections, the second of which is slightly smaller than the first, static pressure sensors of the fluid on the wall of the measuring section of the pipeline in both its sections, and an elastic element with a structurally predetermined area of frontal resistance to flow, cantilevered in the wall inside the channel of the measuring section, and this element is equipped with a force The measuring sensor, as well as the calculator connected to the sensors, the channel of the measuring section, along its length, consists of two parts with a standard, structurally specified, section ratio, part of the channel of the measuring section - each of these two sections is made of the same length and calibrated in diameter , it (the claimed device) is equipped with a second, additional and identical to the first, elastic element installed in the second, smaller, section of the measuring section of the pipeline, while the second elastic element is so

it is also equipped with a force measuring sensor, and both elastic elements are installed in the measuring section of the pipeline in the same horizontal plane diametrically opposite to each other.

Additional differences of the device for measuring fluid flow is that the regular decrease in the second section of the measuring section is 0.7 -t - 0.9 relative to the first; that the length of each part of the channel of the measuring section is three diameters of a smaller section, and the length of the transition from one calibrated section to another is equal to one of the diameters of the channel; that two elastic elements, two static pressure sensors and two force measuring sensors in both calibrated sections are installed in the corresponding parts of the channel of the measuring section of the pipeline at a distance equal to two-thirds from the beginning of each part of the channel with a specific section size.

The presence of the essential features characterizing the inventive device for measuring fluid flow of the above distinctive features and the non-detection in the public sources of patent and technical information of equivalent technical solutions with the same properties, as well as industrial applicability suggest that the claimed object meets the criteria of a utility model.

The drawing shows a schematic diagram of a device for measuring the flow of fluids in a pipeline.

The device consists of (see Fig.) A measuring section 1 of the pipeline with two calibrated internal sections with diameters DI and DI, respectively. The second section is nominally reduced relative to the first. In the parts of the channel with two nominally (structurally) different-sized sections of the measuring section, there are 2 and 3 static pressure sensors (Pi and PI); the outputs of the sensors are connected to the calculator (controller) 4.

in addition, structurally identical elastic elements in the form of plates 5 and 6 with sensors 7 and 8 of the FI and Fi forces located on them, perceiving the bending mechanical stresses of the plates and also connected to each input of the absorber 4 (controller )

It should be noted that (as it turned out experimentally) the optimal ratios of the main structural parameters of the claimed device, made in the form of an insert into the pipeline (as shown in Fig.) Are: the lengths LI and L of both parts of the measuring section 1 should be no more than three diameters D2 parts a channel with a smaller cross section; a smaller, second along the flow section (S2) should be within 0.7-bO, 9 8b identical elastic elements 5 and 6 should not be projected onto each other in the cross section of the flow, and it is desirable that they be located in the horizontal plane diametrically to each other ( to eliminate errors due to the heterogeneity of the fluid along the height of the stream); all measuring elements of the device — in each of the sections Si and 82 — are preferably located at a distance of two thirds of the lengths LI (or L2) from the beginning of each part of the channel of the measuring section with a specific section size; the length of the transition Ln from one section to another should preferably be within the value of one of the diameters (Di or D2), and the transition should be made geometrically smoothed (see Fig.), that is, with the most smooth curvilinear generatrix.

The device operates as follows.

Moving in the measuring pipeline 1, a fluid flow (liquid, gas), running on the elastic elements 5 and 6, creates mechanical stresses in them. These voltages with the help of force sensors 7 and 8 are converted into electrical signals that are fed to the input of the calculator (controller) 4.

The forces (FI and RE), the resistance of the elastic elements 5 and 6 to the fluid flow are determined by the expressions:

p, -5h; (1)

., (2)

where p is the density of the working medium; Vi, 2 are the linear velocities of the working medium, respectively, in sections Sj and 82 of the measuring section of the pipeline; 8c and 84 are the surface areas of the elastic elements perceiving the pressure of the flow. To further simplify the argument, it is accepted that 8c 84 8.

The flow calculation algorithm is reduced to the following operations.

From the known static pressures PI and P2 in the initial part of the channel of the measuring section of the pipeline and in the nominally narrowed part (respectively in sections 8i and 82), the static pressure difference AP is determined:

AP-: Pi-P2. (3)

Using the well-known mathematical apparatus, we express the linear flow velocity through the AP:

DR R, P, / 1 | (,), (4)

At the same time, therefore

Shish

V. -V, - (5)

AR- .K 1-1

Then

V

--f

From work 6 it is known that:, where

- AR and DR2 - dynamic pressure (pressure head) on the elastic elements 5 and 6; these dynamic pressures (pressure head) are determined from formulas (1) and (2):

-X, - coefficient taking into account the unevenness of the energy contribution from the flow rates along the pipeline section, which is in the range 1,, 15.

-Ktr - coefficient of friction of the inner surface of the measuring section of the pipeline (dimension -).

The known AR and p determine the linear velocity of the flow (formulas 7 and 8) and, accordingly, the volume and mass flow rates (Qv and Q):

, S, V, S ,,

imo

2AR

(7)

(8)

 other)

(9)

TR

  ;

(10) 2 S,

  . (AND)

2 5,

or specialized flow transducers, using for this only a measuring section of the pipeline with a two-part channel with nominally different sections, two static pressure sensors, two identical elastic sensing elements cantilever in the channel with force sensors placed on them, perceiving their bending stresses in the material of the elastic elements and connected to the input of the calculator (controller), but it should be noted that the inventive device is quite simple to implement, operate and obs Tinning is especially effective for homogeneous or finely dispersed (i.e., almost uniform) fluids, but for the purpose of commercial accounting of products it requires additional refinement and / or structural complication.

The set of essential features (including distinguishing ones) of the inventive device for measuring fluid flow rate ensures the achievement of the required technical result, meets the criteria of a utility model and is subject to protection by a security document (patent) of the Russian Federation in accordance with the request of the applicant.

SOURCES OF INFORMATION USED IN THE COMPOSITION 1. DESCRIPTION OF THE INVENTION

1. The certificate of authorship .№ 284464, cl. G01P5 / 02, 1970

2. U.S. Patent No. 3,698,245, cl. G01F1 / 00, 1972

3. Certificate of authorship No. 754310, cl. G01P3 / 36, G01P5 / 02, 1980

4. Copyright certificate No. 1037180, cl. G01P5 / 00, 1982

5. Copyright certificate No. 901823, cl. G01F1 / 00, 1982, prototype

6.Journal "Measuring equipment, 1993, No. 6, p. 35 and 36.

Claims (4)

1. A device for measuring fluid flow, containing a measuring section of the pipeline with two cross sections, the second of which is slightly smaller than the first, sensors of static pressure of the fluid on the wall of the measuring section of the pipeline in both its sections, as well as an elastic element with a structurally set frontal drag area flow cantilever mounted in the wall inside the channel of the measuring section, and this element is equipped with a load sensor, as well as a calculator connected to the sensor characterized in that the channel of the measuring section along its length consists of two parts with a standard, structurally defined ratio of sections, the parts of the channel of the measuring section — with each of these two sections — are made of the same length and are calibrated in diameter, it is equipped with a second, additional and identical to the first, elastic element installed in the second, smaller section of the measuring section of the pipeline, while the second elastic element is also equipped with a force sensor, and both elastic elements are installed in and Tonnage pipe section in one horizontal plane diametrically opposite each other. 2. A device for measuring fluid flow according to claim 1, characterized in that the regular reduction of the second section of the measuring section is 0.7-0.9 relative to the first. 3. The device for measuring fluid flow according to claim 1, characterized in that the length of each part of the channel of the measuring section is three diameters of a smaller section, and the length of the transition from one calibrated section to another is equal to one of the diameters of the channel. 4. The device for measuring fluid flow according to claim 1, characterized in that two elastic elements, two static pressure sensors and two force measuring sensors in both calibrated sections are installed in the corresponding parts of the channel of the measuring section of the pipeline at a distance equal to two-thirds of the beginning of each part of the channel part of the channel with a specific section size.