The metrological backup for measurements of the flow rate and volume of liquids and gases in Russia

Gutkin, M. B.; Mishustin, V. I.; Chistyakov, Yu. A.

doi:10.1007/s11018-010-9496-8

Cited by 2 publications

(1 citation statement)

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“…Maximum total absolute error of a flow rate doesn't exceed dimensionless size 0,02 at E 0 = 0,8. Here it is necessary to represent that though the relative error is much more often used in practice because of convenience, however, the essence (physics) of an error always contains in its absolute value [15].…”

Section: Operational Accuracy Of the Dosermentioning

confidence: 99%

About the Precision of the Liquid Doser of Slit Type with Waveformated Surfaces

Nekrasov¹

2018

CTAC&R

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The device is used as an executive element of systems of biomedical assignment and can is used as the precision doser of liquid. The doser represents the slot-hole camera with waveformated surfaces. In contrast to the devices of peristaltic type with an elastic hose the considered device has no essential restrictions of downstream pressure and doesn't contaminate the transported liquid. In work the current of an incompressible fluid in a flat slot of infinite width is considered. Two cases of creation of the waveformated movement in an operating slot are analyzed: the movement in the form of the running wave and the movement in the form of the fluctuations modulated by the running wave. In the latter case, it is possible to implement, irrespective of the required frequency of the running wave, rather big resonant fluctuations of elements of the piezoelectric transducer. It, in turn, allows to receive, at high resonance frequency, a small-size design of the piezoelectric transducer. At the same time in its operating slot there is a longitudinal movement of waves of resonant vibration, and the pressure differentials corresponding to them. Flow of an incompressible liquid in a flat gap is considered. The equation of Reynolds is used for the description of driving of the fluid environment, the decision concerning pressure is brought to analytical expressions or quadratures. The lubricant flow rate and difference of pressure is defined on working length in an explicit form. Increase in pressure and expense in thin layers of an incompressible fluid with growth of amplitude and frequency of wave movements is shown. It is noted that it is slightly less magnitude of pressure differentials and expenses in layers with the fluctuations modulated by the running wave, than in layers with the running wave. These results are assessment from above and can be significantly less at emergence of cavitation in liquid. The analytical results received in work allowed to consider also questions of ensuring accuracy of operation of the doser in the different modes of its operation. It is shown that the largest accuracy of dispensing is reached when transporting liquid from a vessel in a vessel with identical pressure or in case of overlapping of a gap crests of a running wave.

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Section: Operational Accuracy Of the Dosermentioning

confidence: 99%

About the Precision of the Liquid Doser of Slit Type with Waveformated Surfaces

Nekrasov¹

2018

CTAC&R

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Contactless Measurement of Low Liquid Flow Rates

et al. 2014

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A sensor for precise measurements of low flow rates of specialized liquids, including medical liquids, is developed. Through the use of the sensor, it is possible to automate the process of precision dosing of liquids in real time. Keywords: flow sensor, contactless method, drip chamber of infusion system, translucent element.Special attention is now being paid to the problem of increasing the efficiency and precision of measurements of the rate of flow of liquids [1][2][3]. Precision in the measurement of low flow rates of liquids is of great importance in the chemical and biochemical branches of industry and in medicine, for example, for measurements of the rates of flow of solutions of medicines in infusion systems, liquid chemical substances, including catalysts and titers when dosing medicinal compounds, solutions, etc. [4].Existing methods of measurements and devices for implementing these methods [3, 5-7] suffer from a number of drawbacks, for example, large overall dimensions of the devices and the complexity of their construction, low precision of measurements of low flow rates of liquid, and low sensitivity. In addition, with the use of the contact method of measurement, which is employed in practically all devices, a sensor cannot be employed in corrosive and toxic media. These drawbacks reduce the precision with which low liquid flow rates are measured and limit the range of application of the sensors.A measurement instrument by means of which high precision may be achieved and, at the same time, an output signal from the sensing element transformed for subsequent processing, analysis, and generation of control actions is needed for automatic control of the rate of flow.A sensor [8] of low liquid flow rates ( Fig. 1) has been developed to realize precise measurements of low flow rates of specialized liquids. The sensor consists of a case 3 with opaque covers 1, 14 within which mounting screws 2, 13, lens mounts 4, 12, and plates with slit-like horizontal slots 5, 11 are installed. A transparent element 8 is situated in an opening 22 perpendicular to the axis of the case 3. A source of radiation (laser light-emitting diode) 20 with leads 21 is placed in mounting screw 2 while a photodetector (optoelectronic transistor or photodiode) 16 with leads 15 is placed in mounting screw 4. A scattering lens 19 designed in the form of a glass cylinder is mounted in lens mount 4 and a collecting lens 17 in lens mount 12. The translucent element 8 is supplied with an inlet 9 and outlet 18 for liquid and a drop former 10. The two lens 17 and 19 and the two plates with slit-like horizontal slots 5 and 11 form an optical system 6 that transforms the light flux from the radiation source 20 and creates a measurement plane 7 within the transparent element 8.The diameter of the transparent element 8 must be at least three times the diameter of a drop of the liquid being measured and must be greater than the length of the slots in plates 5 and 11. The length of the slot in plate 11 is slightly greater

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The metrological backup for measurements of the flow rate and volume of liquids and gases in Russia

Cited by 2 publications

References 0 publications

About the Precision of the Liquid Doser of Slit Type with Waveformated Surfaces

About the Precision of the Liquid Doser of Slit Type with Waveformated Surfaces

Contactless Measurement of Low Liquid Flow Rates

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