RU12255U1 - DEVICE FOR MEASURING SPEED AND DIRECTION OF MOTION OF GAS AND / OR LIQUID MEDIA - Google Patents

Abstract

A device for measuring the speed and direction of movement of gaseous and / or liquid media, containing a device for measuring the direction of movement and a device for measuring speed with measurement and indication circuits, characterized in that the device is made mainly of three hot-wire anemometric sensors, each of which is connected to its amplifier EMF, connected, in turn, with the computing unit.

Description

A device for measuring the speed and direction of movement of gaseous and / or liquid media.

dumb

This V belongs to the field of measurement technology and can be used5 to measure the speed and direction of gas or liquid flows.

Known devices for measuring the speed and direction of air or water flow, containing a turntable and a windshield (steering wheel), as, for example, in an automatic radio meteorological station M-107 or a marine turntable VMM (1).

In these devices, the pinwheel is a sensor of the flow rate, which is judged by the speed of rotation of the pinwheel, and the flygar turns all the usposts towards the stream and the direction of flow is judged by the angle of the turn. The disadvantages of these devices are large dimensions, weight, lack of reliability and accuracy of measurement. The disadvantages are due to mechanical principles of implementation.

Also known devices for measuring the speed of flows without moving parts, built on the principle of interaction of a heated sensor with a stream. The flow rate is judged by the degree of cooling of the sensing element when washing with a stream. Such devices belong to the class of hot-wire anemometers (2-5). Hot-wire anemometers compare favorably with the above devices: they are miniature, more accurate and durable, have a wide range of measured speeds, and, as a rule, have a circular radiation pattern.

IPC 6: GOIP 5 / 01.5 / 10.5 / 12.13 / 02.

-2 However, the known hot-wire anemometers only determine the speed

flow and do not serve to determine its direction. Therefore, the closest analogue with respect to the claimed solution is the above-mentioned device - VMM marine turntable (1, p. 214-215), which contains a device for measuring the direction of movement and a device for measuring speed with measurement and indication circuits.

The objective of this solution is to create a small-sized device of the hot-wire anemometer principle of operation, which allows you to determine the speed and direction of flow of gaseous and liquid media, and the technical result is to increase the reliability and accuracy of measurement.

The essence of the claimed solution is that the device is made 11 of four sensors, each of which is connected to its own EMF amplifier, which, in turn, is connected to a computing unit.

The inventive device is illustrated in FIG. 1,2. In FIG. 1 shows the relative position of the sensors and the functional diagram of the hot-wire anemometer, figure 2 - graphs of the dependence of the pressure on the direction of flow.

On the device implementation example, the numbers indicate: 1,2.3 - sensors (hot-wire elements), 4 - medium flow, direction 0,5 - flow acting on the sensors at an angle of 120, 6,7,8, - thermoEMF amplifiers, 9 - calculation unit average value and open decay from the average value, 10 - memory block of the direction according to the data of the initial calibration and decoder, 11 - linearization block

flow rate, 12 - flow direction display unit, 13 - flow rate display unit, 14 - graph of the experimental dependence of thermoEMF of sensor 1 on flow direction, 15.16 - the same for sensors 2,3, respectively.

The inventive device operates as follows.

The device is made of three thermoanemic sensors 1,2,3 located at an angle of 120 relative to the center of the structure. Each of the sensors, as a rule, has a pie chart, but, being a part of a complex sensor, the chart of each is distorted due to shadowing by other sensors and the action of their thermal head. The magnitude of thermoEMF depending on the direction of flow will already be NS od 1KaKOBa, as IT would be for a single. plots of this relationship are shown in FIG. 2.

Considering the case of the direction of flow indicated by the number 4 at an angle of 0 °, we see that sensor 1 is partially blocked from the flow by sensors 2,3, and the conditions for cooling it are worse than the other two. The effect of heat fluxes (tails) from the sensors 2,3 also affects. Thus, in this case, the sensor 1 will be hotter than 2.3, and its thermoEMF will be the largest. ThermoEMF of sensors 2,3 is the same and much less than sensor 1 (points 15.1 and 16.1).

If the flow changes its direction to occupy position 5, then in position similar to sensor 1 at O, sensor 2 will appear.

-4 graph this will correspond to point 15.2.

Considering the graph of figure 2, we see that the value of thermoEMF sensors can uniquely determine the angle of the direction of flow. For example, the direction 0 ° will correspond to the numbers -8.24; -8.24; +16.49. These figures determine the deviation of the thermopower of the sensors from the average value in%. When the flow direction changes by 10 °, these numbers will have a value of -7.2; -9.2; +15.97 (points 15.3,16.3,14.3).

Thus, the ratio of thermopower for any direction is determined uniquely. From the graph of figure 2 we see that, despite the deliberate distortion of the directivity diaphragm of each sensor, due to which it was possible to determine the flow direction, the directivity pattern of the set of sensors is very close to circular, because for any direction of flow, the averaged value of thermopower is close to 1940 μV. This value should be taken as a measure of the flow velocity (in the experiment, this is a velocity of 2 m / s).

The output of the sensors 1,2,3 is fed to the input of amplifiers 6,7,8, from which the signals are sent to block 9 to determine the average value and deviation in% of each channel from the average value. The drastic ones U, U, U are received in the memory block 10 and decrypted, then they are sent to the digital block indicating the flow direction 12. The calculated average value is also sent to the linearization block of the flow rate 11 and then to the digital block (scoreboard) of the flow rate 13.

It should be noted that the number of sensors in the inventive device may be different from three and from the angle of their placement 120 however.

the essence remains the same: a complex flow sensor is formed from separate sensors that mutually influence each other, which leads to distortion of the radiation patterns of each sensor, but at the same time to the formation of a pie chart of the total sensor.

The claimed solution allowed to design a device with the following technical data:

- the range of the measured air flow velocity is from 0.1 to 20 m / s;

- speed measurement error - no more than 5%;

- directional diagram - circular;

- the error in determining the flow direction is not more than ± 5;

- head diameter of the integrated sensor - 2.0 mm;

- the number of individual sensors in the head - 3, located at an angle of 120

Sources of information:

1.A.B. Reifer, M.I. Alekseenko et al. Handbook of hydrometeorological instruments and installations. Gidrometeoizdat, Leningrad,, p. 214-215, 297-300.

2.Temnov P.M. et al. Flow rate sensor. Application for invention NQ 2331507 / 18-10, a decision on the issuance of a certificate of the USSR of 04.22.77, MPK2S01R5 / 12.

3.Patent of Poland No. 56523, cl. 420, 1973.

4. Japanese patent No. 48-32152, class. 111A131, 1973.

5. The author's certificate of the USSR No. 1556340, GO IP 5/12, 1986.

Claims (1)

A device for measuring the speed and direction of movement of gaseous and / or liquid media, containing a device for measuring the direction of movement and a device for measuring speed with measurement and indication circuits, characterized in that the device is made mainly of three hot-wire anemometric sensors, each of which is connected to its amplifier EMF, connected, in turn, with the computing unit.