RU92176U1 - DEVICE FOR MEASURING THE CONSUMPTION OF MASS OF GAS AND LIQUID PRODUCTS - Google Patents

Abstract

1. A device for measuring the mass flow of gaseous and liquid products, containing a U-shaped sensing element, both branches of which are located in the same plane and fixed at the ends by mounting brackets, and in the center - in the oscillation mechanism of the sensing element, creating oscillations of the branches in a plane perpendicular to the plane their location, as well as sensors for the dynamic position of the branches of the sensing element, mounted symmetrically on each of the branches. ! 2. The device according to claim 1, in which the sensing element is made in the form of two U-shaped tubes located in parallel in the plane of the working vibrations. ! 3. The device according to claim 1, which is equipped with a displacement sensor installed in the location of the oscillation mechanism.

Description

The utility model relates to measuring equipment and can be used in the gas, oil, chemical and food industries.

The prototype of the utility model is a mass flow rate measuring device containing a tuning-fork type sensitive element made of two U-shaped tubes mounted on a sensitive element of a signal pick-up adapter, an excitation and signaling device, including a series-connected amplifier with an automatic adjustment device and an excitation electromagnet, phase discriminator and voltage-to-frequency converter, as well as precision integrators, a rectifier and a low-pass filter - and t. testimonial. USSR No. 1739204, G01F 1/84, 1992

In the known device during its operation, the moments of the Coriolis forces cause the appearance of a turn of each U-shaped tube, moreover, the angle of the turn is proportional to the mass flow rate of the current flowing through the device.

The disadvantage of the prototype is its significant structural rigidity, due to which the Coriolis forces for turning the tubes must overcome both the moment arising from torsion twisting in the tubes themselves and the reaction time of the support of their fastening. The result is low sensitivity and repeatability of measurement results at low flow rates.

In this regard, the technical problem solved by the utility model is to increase the sensitivity and accuracy of measurements by reducing the rigidity of the structure due to the exclusion of the reaction time of the supports of the sensitive element.

This problem is solved in a device for measuring the mass flow of gaseous and liquid products containing a U-shaped sensing element, both branches of which are located in the same plane and fixed at the ends by mounting brackets, and in the center - in the oscillation mechanism of the sensing element, creating oscillations of the branches in the plane, perpendicular to the plane of their location, as well as sensors for the dynamic position of the branches of the sensing element, mounted symmetrically on each of the branches.

One of the private implementations of the device is the implementation of the sensitive element in the form of two U-shaped tubes located in parallel in the plane of the working vibrations.

Another particular embodiment of the device is the use in it of a displacement sensor installed at the location of the oscillation mechanism.

The drawing shows a view of the device in the plane of the U-shaped sensitive element.

The device contains a U-shaped sensing element 1, both branches 2, 3 of which are located in the same plane and are fixed at the ends by mounting brackets 4, 5, as well as fixed in the center, in the mechanism 6 of the oscillations of the sensitive element 1, creating oscillations of the branches 2, 3 in a plane perpendicular to the plane of their location. Sensors 7, 8 of the dynamic position of branches 2, 3, respectively, are located symmetrically on each of the branches.

The device operates as follows.

The measured flow 9 is pumped through a U-shaped sensing element 1, held by mounting brackets 4, 5. In this case, the mechanism 6 creates operating vibrations of the sensing element 1 in a plane perpendicular to the plane of its location. The Coriolis forces arising in the branches 2, 3 lead to the appearance of the rotation angles of the tubes of the sensing element 1 and, consequently, to the lag and ahead of the corresponding branches 2, 3 relative to the working vibrations of the device. Since the mounting brackets 4, 5 are located as close as possible to each other, the reaction of their supports, compensating for the moment of Coriolis forces, is minimal and does not reduce the angle of rotation of the sensitive tubes, which increases the overall sensitivity of the device.

A computing device (not shown in the drawing), using signals from the sensors 7, 8 of the dynamic position, determines the mass flow P of the pumped stream 9 by the formula:

P = Kφ,

where: K is the calibration coefficient determined experimentally for a particular measuring device, φ is the phase difference of the oscillations of the branches of the U-shaped sensing element 1, determined using sensors 7, 8.

Table 1 shows examples of determining the mass flow rate by the specified formula.

Table 1 K φ P glad kg / s 34.35 0,0356 1.2232 34.35 0,0383 1,3146 34.35 0.0425 1.4595

If in the device the sensing element 1 is made in the form of two U-shaped tubes parallel to the plane of the working vibrations, the oscillation mechanism 6 creates vibrations of the tubes relative to each other, and the sensors 7, 8 of the dynamic position of the branches measure their relative position, determining the phases of the vibrations of the branches 2, 3. In this case, the mass flow rate is determined similarly to the above.

The device when it is executed with the displacement sensor 10, which allows to determine the density of the medium, works as follows.

During oscillations of the sensing element 1 under the action of the mechanism 6, the displacement sensor 10, installed at the location of the mechanism 6, produces a signal proportional to this displacement, which, as a feedback signal, is supplied to the oscillation generator (not shown in the drawing). As a result, the oscillation frequency of the sensing element 1 using the oscillation generator is set corresponding to mechanical resonance.

A computing device (not shown in the drawing), using signals from the displacement sensor 10, determines this resonant frequency f and calculates the density according to the formula:

where: A, B, C are calibration coefficients, f is the frequency of resonant vibrations, ρ is the density of the medium being measured.

Table 2 shows examples of determining the density of the measured medium according to the specified formula.

table 2 f A B C ρ hz 85 96 fifteen 0.75 0.9398 one hundred 96 fifteen 0.75 0.9096 150 96 fifteen 0.75 0.8543

Thus, the proposed device has increased sensitivity and accuracy of the results of measurements of mass flow due to the fact that it minimally influences the moment of fastening reaction, and, as a result, the moments of Coriolis forces overcome only the moment of torsion twisting. In addition, with its help it is also possible to measure the density of the medium.

Claims (3)

1. A device for measuring the mass flow of gaseous and liquid products, containing a U-shaped sensing element, both branches of which are located in the same plane and fixed at the ends by mounting brackets, and in the center - in the oscillation mechanism of the sensing element, creating oscillations of the branches in a plane perpendicular to the plane their location, as well as sensors for the dynamic position of the branches of the sensing element, mounted symmetrically on each of the branches. 2. The device according to claim 1, in which the sensing element is made in the form of two U-shaped tubes located in parallel in the plane of the working vibrations. 3. The device according to claim 1, which is equipped with a displacement sensor installed in the location of the oscillation mechanism.