SU1112237A1 - Stand for graduating liquid flowmeters - Google Patents

Abstract

STAND FOR GRADUATION OF A FLUID-FLOW METER, containing a drain tank and a measuring tank located above its bottom with a high-speed hydraulic lock, made in the form of a vertical pipeline of constant cross section, enclosing. Since, in order to reduce the graduation error, the lower end of the measuring tank is located at the distance from the bottom of the drain tank not less than the height of the vertical pipeline to be filled with liquid.

Description

The invention relates to a measurement technique, in particular, to means of calibration and calibration of liquid flow meters.

Known volumetric metrological stand that contains the measuring capacity in videcolen, a system of valves that ensures the flow of fluid from one branch of the knee to another, and recording equipment. The work of this stand is based on determining the dependence of the velocity (volume) of a fluid on O. time.

The disadvantage of the test bench is the error of graduation that occurs during unsteady fluid movement in the test section due to the error of the means of controlling the movement of the interface, as well as the controls of the stand.

The closest technical solution to the proposed one is a stand for calibration of liquid flow meters, containing a base with a drain tank installed on it with a high-speed hydraulic lock made in the form of a vertical pipeline of constant cross section Hg.

However, the known stand also has insufficient accuracy due to the presence of an error associated with the distortion of the readings of the measuring device during unsteady fluid flow.

The aim of the invention is to reduce the calibration errors of liquid flow meters.

This goal is achieved by the fact that in the stand for calibration of liquid flow meters containing a drain tank and a measuring tank located above its bottom with a fast-acting hydraulic lock, made in the form of a vertical pipeline of constant cross section, the lower end of the measuring tank is located at a distance from the bottom of the drain container not less than the height of the part of the vertical pipeline to be filled with liquid.

The drawing shows the scheme of the stand.

The stand includes measuring tank 1, graduated flow meter 2, hydraulic lock 3, ejection device A, drain tank 5 and recording equipment 6 (t, is the height of the measuring tank or its filled part.

counted from the surface of the separating element of the hydraulic lock to the mark that determines the degree of filling of the measuring capacity; -n height of the free fall section of the fluid is counted from the surface of the separating element of the hydraulic seal to the bottom of the drainage tank).

The stand works as follows.

After installing the calibrated flow meter 2, the lower opening of the measuring tank 1 is hermetically sealed with a hydraulic lock 3, after which the ejection device 4 is charged and the measuring tank 1 is filled with liquid to a given level.

Using the trigger signal, the catapult device 4 opens the hydraulic lock 3, and the liquid column starts its movement inside the measuring tank 1 with the acceleration of free fall. The recording equipment 6 records the readings of the flow meter 2 in time, which is counted from the moment of the full opening of the hydraulic shutter 3 by the ejection device 4.

To construct the metrological characteristics of the flow meter 2, its readings recorded by the recording equipment 8 are compared with the actual values of the flow rate GI (i-) calculated by the formula

a (0-qi-S

where o free fall acceleration

S is the area of the living section of the moving volume of fluid in the measuring capacitance

. i is the time counted from the moment of full opening of the hydraulic shutter 3. The main dependences between the initial height of the liquid column in the measuring capacity and the speed Vli of its movement are obtained from the differential equation describing the movement of the liquid in a vertical pipeline

where 1 is the vertical coordinate

numerically equal to the path traveled by the liquid column, M,

311122374

C is the coefficient of aerodynamic f frfit. Bv -, - g A R / h. Whom is the resistance of the column - (- (.-))} fluid J

11 - coefficient of hydrodynamics-D.1.g

5 K resistance

vertical pipeline; gaL ii M - mass: liquid in dimensional R

capacities, kg; “- integral of probability, —density of liquid, kg / m; Rj is the hydraulic radius P — the perimeter of the midsection section of a multi-split section of the measuring capacity, m; capacity; m.

9. Air density, kg / m. The proposed stand provides

Dependence for speed V (tl-1 reduction of graduation error

derived from the solution of a given liquid flow meter due to

When zero initial conditions are missing, the process of measuring the liquid flow through the races (iy.jr "/% exo / -i-- r (the meter, in addition, it is of design and operation).

Claims (1)

A STAND FOR GRADING LIQUID FLOW METERS, containing a drain tank and a measuring tank located above its bottom with a quick-acting water seal, made in the form of a vertical pipeline of constant cross section, revealing that, in order to reduce the calibration error, the lower end of the measuring tank is located from the bottom of the drain tank at a distance not less than the height of the vertical pipeline to be filled with liquid.