SU398829A1 - METHOD FOR DETERMINING VOLUME OF CAPACITIES - Google Patents

Description

one

The invention relates to the field of measurement technology and can be used, in particular, to determine the volume of untight containers.

When determining the volume of containers by known methods based on measuring the pressure change of the gas flowing out of them over time, it is necessary to seal them, which is not always possible to provide.

In order to expand the range of application, the proposed method additionally measures the gas flow depending on the pressure and, using the data obtained by calculation, determines the desired volume.

FIG. Figure 1 shows a plot of overpressure (or vacuum) P in the internal floor (tank) versus time / gas outflow through leakages. The time interval from ti to / 2 is indicated. during which a change in overpressure (vacuum) is considered; in fig. 2 is a graph of the weight flow of gas G as a function of the overpressure (vacuum) of the DS in the tank; in fig. 3 - a graph of the dependence of the weight of the gas flow through the lack of capacity of the tank from time to time (t). The shaded area indicates the weight of the gas that has passed through leaks over time.

2

t., - t, G (f) dt). fi

The volume of the container according to the proposed method is determined in the following manner.

They create an overpressure (vacuum) in the internal cavity, for example, with a fan. Close the channel through which create pressure (vacuum) in the tank. The excess pressure is measured over time. The dependence P f (t) is constructed (Fig. 1).

The gas is supplied (sucked off) into the internal cavity, by means of the same fan. At various steady flow conditions through non-containment, the excess pressure (vacuum) in the internal gas and gas flow rate is measured. The dependence G f (APj (Fig. 2)) is constructed.

Consider the process of changing the overpressure (vacuum) in the internal floor of the tank for running the weft time from

/ 1 to t2.

Determine the weight of the gas that has passed through the heatiness during this period, for example, by constructing the dependence 0 f (t) (Fig. 3) using the dependences

(AP) and DYa / ()

thirty

and subsequent graphical integration.

Calculate the internal volume by the formula:

t, RT G G (t) dt

v,

APi - DR.,

where R is the specific constant of the gas in the inner KGM

Cavities

kg-hail

the temperature of the gas in the tank, ° K;

weight of gas passing through

leakages in the period from t to / 2, kg;

APi; - overpressure (rarefaction) in the internal cavity at times ti and / 2, respectively.

The formula is valid for the case of creating an overpressure in the measured capacity, as well as for the case of creating a vacuum. In the latter case, the weight of the gas and the difference between the initial and final pressures have negative signs.

Subject invention

The method of determining the volume of containers by measuring the pressure change of gas flowing out of them over time, characterized in that, in order to broaden the application range, the gas flow is additionally measured depending on the pressure and the volume sought is obtained from the calculated data.

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