SU1712888A1 - Gas and fluid flow direction/rate meter - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the velocities of three-dimensional flows of liquids or gases. The purpose of the invention ffi '"-Mflü00 00 00

Description

The invention relates to a measurement technique and can be used to measure the velocities of three-dimensional flows of liquids or gases.

A device for measuring the velocity and direction of a flow of a liquid or a gas is known, comprising a receiving element and a collector with nozzles for determining the deviation of the receiving element under the action of the flow.

The disadvantage of this device is its low accuracy due to the fact that the lateral collector nozzles are angled to the longitudinal axis of the sensor.

The closest in technical essence to the present invention is a device for measuring the velocity and direction of flow of a liquid or gas, which comprises a cover, a housing, a manifold with channels in it, a membrane connected to a rod and a spherical probe. The channel collector and the rigid center of the membrane are made in the form of conjugated semi-ellipsoids of rotation and form pneumatic sensors of the nozzle-flap type.

However, due to the technological difficulties of ensuring a strict elipsoidality of the collector surface and the hard center, as well as the need to maintain a uniform gap between them, uncontrollable error is deliberately introduced into the output pneumatic signals. It is difficult to maintain the same gap thickness due to the high flexibility (low elasticity) of the membrane, which may be the reason for the insufficiently high accuracy of the measurements. In addition, a disadvantage of the known device is the large measurement error of the pneumatic signals due to the mutual influence of the air jets in the adjacent nozzles, as well as the mutual influence of the pressure values in the signals of the measuring system. For example, as Pi increases and P2 decreases (the velocity of the medium flowing from right to left is measured), the RZ signal may change, falsely indicating the presence of a vertical velocity component. This disadvantage is compensated, but not eliminated, by a large amount of calibration measurements, which, as a result, makes it difficult to decipher the experimental data. The error increases due to the mutual influence of the signals from the horizontal nozzles. The disadvantages include the instability of the output signals due to the high compliance (low elasticity) of the membrane, which is the only elastic structural element. For example, under the action of air pressure from the nozzles

the hard center can overcome the elasticity of the membrane and fall below the permissible value of the deflection, which will cause the device to be practically inoperable or

will create a self-oscillating uncontrollable system with obviously inadequate pneumatic output signals. Thus, the reliability of the device operation is not ensured and the measurement range is deliberately limited (due to the ultimate elasticity of the membrane).

The aim of the invention is to improve the accuracy and the expansion of the measurement range of the device.

5 The goal is achieved by the fact that in a device comprising a lid, a housing and sensors located therein such as a nozzle valve, as well as a membrane fixed in the housing, through which a rod is connected that connects one end to a ball probe and the other end to a rigid center in the form of a damper. , the sensor flap is made in the form of a flat circular disk located horizontally, and below and above

5 perpendicular to its flat surface, nozzles are mounted in pairs, parallel to each other and located at equal distances from the axis, the upper nozzles being placed in a plane perpendicular to the plane in which the lower nozzles are installed, and both indicated planes pass through the axis of the housing wherein the sensor flap is connected to the center of its upper plane with an elastic compensating element, such as a spring, the upper end of which is coaxially fixed inside the body on the lid with the possibility of tension control, and on both surfaces of the flat flap opposite the nozzle sections, deflector grooves are made in the form of spherical segments.

Figure 1 presents the proposed device, a General view; figure 2 - pneumatic sensors such as a nozzle-flap, iso5 metry.

The device consists of a flat cover

1 (Fig. 1), hermetic enclosure 2, at the bottom

parts of which is located tight

. membrane 3, through which the center is passed

0 vertical rod 4. At the upper end of the rod 4 in the horizontal plane, i.e. perpendicular to it, the valve 5 is fixed in the form of a flat circular disc, and a ball valve is mounted on the lower end.

5 probe 6. Through the cover 1, the pneumatic lines 7-11 with nozzles are passed. The pneumatic lines 7 and 8 are pneumatically connected through the gap with the upper plane of the valve 5, and the other two pneumatic lines 9 and with its lower plane. Pneumatic duct 11 connects

the cavity of the housing 2 with a source of pressure of compressed air. The upper plane of the valve 5 is connected to the elastic element 12., for example, by a spring, the upper end of which is fixed coaxially on the cover 1 and the tension of which is regulated by means of a screw 13.

The nozzles of the pneumatic lines 7 and 8 are located vertically in plane A (Fig. 2), passing through the longitudinal axis of the device, and at equal distances from the axis, and the nozzle sections are spaced from the upper flat-out valve by the size of the gap adopted in nozzle-type devices. - A flap that is 1-3 mm, depending on the range of measured speeds.

The nozzles of the pneumatic lines 9 and 10 are also located vertically, but in such a vertical plane B, which is perpendicular to the plane A and intersects the axis of the device, and is pneumatically connected to the lower plane of the valve 5.

The membrane 3 is fixed on the lower part of the housing 2 by means of a ring 14.

Spherical segment grooves 15-18 are made on the upper and lower planes of the flap 5 opposite to the nozzle cuts of the pneumatic lines 7-10, which allow forming a jet of air entering the nozzle, eliminating undesirable interaction of the jets at the nozzle entrance of the pneumatic line (pressure pulsations) and reducing the registration error pneumatic input signals.

The device works as follows.

Through the air line 11 into the cavity of the housing 2, air is compressed at a predetermined pressure. Through the receiving nozzles of the pneumatic lines 7-10, air enters the corresponding measuring pneumatic lines and then is supplied to the pneumatic signal measurement system, for example, strain gauge micromanometers and a microprocessor based on a vertical computer MS 0585 Electronics, which processes the signals and accurately determines the magnitude of the velocity and flow direction .

In the absence of flow rate and, therefore, the cart; act on ball probe b

PI P4 signals are constant and equal by

magnitude. This is achieved by adjusting the force of the spring 12 with the screw 13. Next, when the probe 6 acts on the probe 6, the rod 4 rotates, overcoming the tension of the spring 12 and causing the valve 5 to move, causing, for example, the nozzle of the pneumatic conduit 8 to cover (the medium moves from left to right ), and the nozzle of the pneumatic line 7 opens slightly.

When exposed to the medium in plane B (Fig. 2), the signals change accordingly in the nozzles of the pneumatic lines 9 and 10, and the pneumatic signals in the nozzles of the pneumatic lines 7

and 8 may remain unchanged.

The measurement of the vertical direction of velocity, HanpviMep from the bottom up, is accompanied by a decrease in the gap of the nozzles of the P1 electrical lines 7 and 8 and an increase in the gap

0 near the nozzles of the pneumatic lines 9 and 10. When flowing from the top to the bottom, the nozzles of the pneumatic lines 9 and 10 are covered, and the nozzles of the pneumatic lines 7 and 8 are opened.

5 When the probe 6 is removed from the medium, thanks to the spring 12, the flap 5 and the rod 4 return to their original position.

By adjusting the tension

0 spring 12 device can be configured for different speed measurement ranges. For example, when it is weakened, the sensitivity of the device increases, which allows for measuring small speeds. With

5 tensioning it and simultaneously reducing the compliance of the device provides measurements of higher speeds.

In addition, the spring 12 stabilizes, the axial position of the valve, not allowing it

0 oscillate spontaneously when measuring the velocity of the medium and thus create false measuring signals.

 Applying the invention improves the accuracy of the flow rate measurement.

5 by eliminating the mutual influence of pneumatic signals and thus increasing the reliability of the information received, as well as increasing the reliability of the device, eliminating the influence of random

0 mechanical effects on the performance of the measurement system, and expand the measurement range by changing the sensitivity.

Absence - in the electronic device,

Claims (2)

01. Device for measuring speed and the direction of the pot. of a liquid or gas, comprising a cover, a housing and sensors of nozzle-flap type located therein, as well as a membrane fixed in the housing, 5 through which a rod with a rigid center in the form of a flap is passed, characterized in that, in order to improve the accuracy and expansion of the working range of measurements, it additionally contains an elastic compensating element, and The sensor slide is made in an ideally flat disk located horizontally, with sensor nozzles arranged in pairs below and above the disk surface, parallel to each other and located at equal distances from the housing axis, with the upper nozzles located in the axial plane, perpendicular to the axial the plane of the bottom nozzles, the center of the flap sensors at the top is connected to the lower end of the elastic compensating element, the upper end of which is coaxially fixed inside the body to the lid, and deflector grooves are made on both flat surfaces of the valve opposite the nozzle cuts. 2. The device according to Claim 1, in connection with the fact that the elastic compensating element is adapted to adjust the tension.