SU1720019A2 - Device for measuring flow velocity - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure velocities in a suspension fluid stream. The aim of the invention is to increase accuracy for. the expense of automating the process of obtaining measured speed values. Under the action of the velocity head, the fairings 7 and 8 are displaced in the direction of flow. When this happens, the volumes of the chambers of the full pressure receivers change: the volume of the chamber, the first in the direction of flow, decreases, the second increases. A change in the volumes of the chambers leads to a change in the fluid levels in the gauging tubes 1 and 2. Electrolytes with equilibrium reactions with different electrical conductivities are used as the working fluids in the tubes. Therefore, the occurrence of level differences in tubes 1 and 2 leads to a change in the resistance of the electric current in tube 1 between electrodes 11 and 13. As a result, a voltage drop occurs between electrodes 16 and 17, which carries speed information and is recorded by a voltmeter 18. 2 Il. (L

Description

The invention relates to a measurement technique and can be used to measure velocities in a suspension fluid stream.

A device for measuring the speed of a contaminated flow is known, which contains two hydrometric tubes assembled in one package and forming a V-shaped siphon. The inlets of the tubes communicate with hermetically connected full-pressure receivers, which consist of rigid plates connected by elastic nozzles and with a holding plate rigidly fixed to the hydrometric tubes.

The disadvantage of such a device is the need to visually determine the level difference between the working fluids directly at the installation site of the device by counting the levels in the flow tubes and converting the obtained level differences to the local velocity value. This reduces the accuracy of measurements.

The aim of the invention is to improve the accuracy of the device by automating the process of obtaining measured speed values.

This goal is achieved by the fact that in a device for measuring the flow rate, containing two hydrometric tubes, assembled in one package and forming a V-shaped siphon, the inlets of the tubes communicate with hermetically connected full-pressure receivers connected to them, connected by elastic pipes

Yu

Yu

by cuttings and with a plate holder rigidly fixed on hydrometric tubes, hydrometric tubes are filled with working fluids in the form of electrolytes with equilibrium reactions having different electrical conductivities, with pairs of electrodes located at the same level as well as at the level of contacts of the working fluids, connected in parallel to a power source, between which additional electrodes are also located at the same level, connected to a voltage indicator.

FIG. 1 shows the structure of the device; in fig. 2 - his electrical circuit.

The device contains two hydrometric tubes 1 and 2, collected in one package and forming a V-shaped siphon. The inlets of tubes 1 and 2 are connected with hermetically connected full-pressure receivers, which consist of rigid plates 3, which are rigidly connected to each other and elastic nozzles 4 and 5 with a plate holder b fixed on the hydrometric tubes 1 and 2.

On the plates 3, fairings 7 and 8 are mounted. In the upper part of the flow tubes 1 and 2, taps 9 and 10 are located to fill the device with working fluids. At the level of contacts of working fluids, in both tubes 1 and 2 at zero speeds in the flow, when these levels are at the same level, electrodes 11 and 12 are located, and in the upper part of tubes 1 and 2 - electrodes 13 and 14, through which the parts of tubes 1 and 2 located between these electrodes and filled with working fluids are connected in parallel to the source 15 of electric current. Between Electrodes 11 and 13, 12 and 14 are located electrodes 16 and 17, respectively, in tubes 1 and 2, interconnected through a voltmeter 18, graduated from the measured speed, and / or a self-recording voltmeter. The lower working fluid 19, for example, an aqueous solution of blood salt paint, is located in the lower part of the tubes 1 and 2, and the fluid 20, which has a lower specific density and is mutually insoluble with water, is located in the upper part of the tubes 1 and 2. Electrical conductivity (resistance) of liquids 19 and 20 different. A voltmeter 21 (or a recorder voltmeter) is connected to the electrodes 12 and 14, the electrodes 11, 12, 13, 14 and 16, 17 are made, for example, in the form of rods arranged perpendicular to the tubes 1 and 2.

The device works as follows.

Under the action of the velocity head, the fairings 7 and 8 are displaced in the direction of flow. When this happens, the volumes of the chambers of the full pressure receivers change: the volume of the chamber, the first in the direction of flow, decreases, the second increases. A change in the volume of the chambers leads to a change in the fluid levels in the gauging tubes. The appearance of the level difference in tubes 1 and 2 leads to a change in the resistance of the electric current in tube 1 between electrodes 11 and 13, since the liquid columns 19 and 20 have different electrical conductivities in

This tube height. As a result, a voltage drop of electric current occurs between the electrodes 16 and 17, the magnitude of which is measured by a voltmeter 18, and / or recorded by a self-recording voltmeter.

The operating voltage of the sources is monitored by a voltmeter 21,

For the circuitry of the device shown in FIG. 2, the force in the tube 1 is equal to

fl G20L (L-h) -f p Iol

where U is the operating voltage of the current source 15; n and hey. - resistivity, respectively, of liquids 19 and 20; wi is the cross-sectional area of the tube 1; L is the distance between the electrodes 11 and 13, 12 and 24; h is the distance between the level of contact of working fluids in the tube 1 at the measured speed and at the flow rate equal to zero.

The voltage of the tube 1 on the electrode 16, when the contact level is below the electrode, is equal to

LW1P2 U

UiHiwira j. (L-h) + {2)

The voltage in the tube 2 on the electrode 17 corresponds to

From here AU Ui-Uii,

di

G2§i

U

r2 (L-h) + nh 2

h (r2-n) U (L-h) + nh

(four)

55

or

(five)

For the case when n p, from relation (5) we have

AU-Uh I .ffiv

2 L., n (6)

1 L

From relation (6) we find h AU

h AU.

L + 2L or, taking in charge that

h-prv2, (8)

where v is the average flow rate flowing on the device sensor;

 coefficient of proportionality. Substituting the value of h from formula (8) in dependence (7), we get

1AUt

(9)

G pi (AU + 0.511)

Relationship (9) allows you to set the relationship scale A U with known U and L, with a measured value of averaged speed v for a voltmeter 18, and, therefore, to use it to measure the speed in a stream. Relationship (9) can also be used to calibrate tapes of a recording voltmeter. When,

five

ten

15

0 5

when condition G2p is not met, dependencies (5) and (8) are used for similar purposes.

Claims (1)

The invention The device for measuring the flow rate according to ed. No. 1037180, which differs from the fact that, in order to increase accuracy by automating the process, recording information about the flow rate, the hydrometric tubes are filled with working fluids in the form of electrolytes with equilibrium reactions having different electrical conductivities, while each of the tubes is located one above the other; the contact zones of working fluids are located at the same level, and three pairs of electrodes are installed in the tubes, each electrode of a pair of electrodes is located at the same height in each of the tubes OK, one of the electrode pairs is located in the contact zones of the working fluids, and the other two, respectively, above and below the contact zones, the electrodes are connected in parallel to the power source, and the electrodes in the contact zone are connected to a voltage indicator. FIG. 2