UA147610U - METHOD OF DETERMINING THE VOLUME OF A VESSEL - Google Patents

Abstract

The method of determining the volume of the vessel includes changing the volume of the vessel by the amount and determining the gas pressure in the vessel before and after the change in volume. The measured vessel is pre-filled with air, the change in volume of the measured vessel is carried out by connecting it to a reference vessel with a predetermined volume, before and after changing the volume its pressure and temperature are measured after establishing a constant ratio, and the volume of the measured vessel determined by the formula:, where, - pressure and temperature in the measured vessel before changing the volume; , - pressure and temperature in the measured vessel after change of volume.

Description

The useful model belongs to non-destructive measurement methods and can be used to measure in an air environment the volume of the internal cavity of a vessel with a complex geometric shape in various branches of mechanical engineering.

There is a known method of measuring the volume, which consists in replacing the desired volume with a liquid (water, oil, etc.) and then measuring its volume with a measuring device, which uses a measuring flask, burette, cylinder, beaker, etc. (Hauzner S.1I., Kivilis S.S., Osokina A.P.,

Pavlovsky A.M. Measurement of mass, volume and density. Moscow: Standards Publishing House. 1972. 623 p.).

The disadvantage of the known method is the need to clean the vessel of liquid after measurements, which increases the measurement error, since not all the liquid is measured by the meter - part of it remains on the walls of the vessel. The presence of the procedure for filling and removing liquid from the vessel complicates and increases the duration of measurements. In addition, the indicated method has limited possibilities for application, since it can be used only for those vessels for which contact with the liquid does not cause harmful consequences in the form of its absorption by the surface layer, swelling, dissolution, corrosion, clogging of micropores, etc.

There are known technical solutions that allow you to determine the volume of vessels in an air environment.

In particular, a number of methods of measuring the volume of vessels in various versions are known, based on the measurement of the resonant frequency of the vessel (pat. RF Mo 2131590, MPKO (401E 23/28; pat.

BA Mo 4640130, publ. MPK (01M 29/00, SOTE 17/00; pat. OBA Me 7578183, MPKO SOTE 23/28, SOTE 17/00), which allow determining the volume of vessels in an air environment. The essence of the methods is that acoustic oscillations are excited in the measured volume of the vessel with a frequency equal to the resonant frequency of the measured volume, the value of which is used to calculate the value of the measured volume using certain formulas. The disadvantages of the methods are the complexity of their technical implementation and the low accuracy of measurements for vessels of complex shape.

Known methods of determining the volume in closed vessels, based on the measurement of gas leakage parameters (pat. RF Mo 2079112, MPKO) СО1Е 17/00; stalemate. RF Mo 2217721, MPKO SO1M 3/26,

Sauté 17/00; stalemate. RF Mo 2292536, IPC (201М 3/26, СОТ1Е 17/00). The essence of the methods is to create excess pressure in the vessel, determine the pressure and temperature in it, make air flow through calibrated flows, determine the pressure drop time intervals and calculate

Based on measurement of time intervals, pressure and temperature of the gas in the vessel, its volume.

The disadvantage of the methods is the low measurement accuracy due to the fact that the formulas used to calculate the volume are quite complex, the result depends on many parameters, and the calculated dependence of the volume on the pressure drop time is non-linear. The disadvantage of the methods is also the increased duration of the measurement procedure, which is associated with the need to use the procedure of air supercharging and its release through calibrated flows, to determine the parameters of which additional tests are required using a reference volume and composition of the air environment that has characteristics close to to measurable. During the measurement, the parameters of the air environment, in particular, the temperature, can change, be unevenly distributed inside the vessel, which changes the flow conditions and introduces an uncontrolled error into the measurement result.

The closest in terms of purpose and technical essence is the method of measuring a vessel (pat. RF Mo 2494352С1, IPC СО1Е 17/00), according to which the volume of the vessel is changed by the amount of DM and the change in gas pressure in the vessel is determined before and after the change in volume. to him, on the basis of which the desired volume of the vessel Mo is determined, at the same time, the pressure in the hermetically closed vessel is first equalized with the environment, by moving the rod, its volume is changed by the value of АМі and the pressure АРИ inside the vessel relative to the external environment is measured, they make sure that it does not change over time, change the volume of the vessel by the value of ADM, equalize the pressure in the vessel with the environment, again change the volume of the vessel by the value of DM", measure the pressure of AR" inside the vessel relative to the external environment and again make sure that it is not changes over time, and the desired volume of the vessel is recognized by the formula: (АР» / АМо - АР, / АМ.) where K-1, if the volume of the vessel is reduced, and K--1, if it is increased.

The disadvantage of this method is the increased duration and complexity of ensuring high accuracy of volume measurement.

These disadvantages are caused by the fact that in the known method of determining the volume of the vessel, it is carried out using the effect of constancy of gas compressibility at constant gas pressure and temperature. But a change in the gas volume inevitably leads to a change in its temperature, which in turn leads to an additional change in pressure, which is not taken into account in the formula used in the known method to calculate the measured volume. This leads to an uncontrolled error in determining the volume of the vessel. In addition, the requirements for carrying out measurements after establishing a constant pressure specified in the known method are provided only if a constant temperature is established due to heat exchange between the environment, the vessel and the gas inside it, which takes a long time, taking into account the low thermal conductivity of gases. This significantly increases the time of determining the volume of the vessel when using the known method.

The useful model is based on the task of increasing the accuracy of determining the volume of the vessel while simultaneously reducing the measurement time.

The problem is solved by the fact that the method of determining the volume of the vessel includes changing the volume of the vessel by the value AM and determining the gas pressure in the vessel before and after the change in volume. The measuring vessel is pre-filled with air, the volume of the measuring vessel is changed by connecting it to a reference vessel with a predetermined volume

AM, before and after the change in volume, its pressure Р and temperature 7 are measured after establishing a stable pressure Р/; and the volume of the measured vessel is determined by the formula: и (Р/то - Р» Ti) de Ri ; t pressure and temperature in the measured vessel before the change in volume;

R"; i.e. pressure and temperature in the measuring vessel after the change in volume.

The method is implemented as follows. The reference vessel with the defined volume of ADM is connected to the measured vessel using a normally closed tap or valve. At the same time, all elements of the gas tract are filled with air. Compressed air is fed into the measuring vessel.

At the same time, it simultaneously changes both pressure and temperature, which are measured using sensors. These changes take place both in the process of filling the vessel with compressed air and after its supply is stopped and continue until the temperature equilibrium is established between the structural elements of the gas tract, the air inside it and the surrounding atmospheric air. The duration of this process is determined by the thermal conductivity of the air and can take a long time. But it is not necessary to establish such a balance for measurements. For this, it is sufficient to establish constant parameters that determine the mass of gas in the gas tract. Based on the equation of state of an ideal gas, PM-tAT is necessary for this

On reaching the condition of R/G-sop5i. After its execution, the values of pressure Pi and temperature Ti should be measured at an arbitrary moment in time. After that, the tap or valve connecting the measured and reference vessels is opened, and air flows from the measured vessel to the reference vessel. After re-establishing a constant value of the value of P//-:sop5i, new values of pressure Po and temperature T" are measured. Based on the fact that the mass and composition of gas during both ee Ky sho D

From where the volume of the measured vessel is determined as: (Pi - P»)

At the same time, due to taking into account the simultaneous change in pressure and temperature of the gas in the measured vessel, the accuracy of determining its volume increases due to taking into account the effect of temperature on pressure. Using the condition of achieving a constant R/T ratio does not require establishing a constant temperature due to the heat exchange between the environment, the vessel and the gas inside it, which, taking into account the low thermal conductivity of air, significantly reduces the time for determining the volume of the measured vessel. Thus, the proposed method of determining the volume of the vessel allows you to achieve the set technical result, namely, it allows you to increase the accuracy of determining the volume of the vessel while simultaneously reducing the measurement time.

Claims (1)

USEFUL MODEL FORMULA The method of determining the volume of a vessel, which includes changing the volume of the vessel by the amount M and determining the gas pressure in the vessel before and after the change in volume, which is characterized by the fact that the measured vessel is pre-filled with air, the volume of the measured vessel is changed by its connection with a reference vessel with a predetermined volume В, before and after the change in volume, its pressure P and temperature 7 are measured after establishing a constant ratio P/T, and the volume of the measured vessel is determined by the formula: mo - AM-- 21 o - --fЧЯ -2 хЯ« (5 х(:(|Я Я 6 -tya (R/to - Rot) de Ri ; t pressure and temperature in the measuring vessel before the change in volume; P; ; t. pressure and temperature in the measuring vessel after the change in volume.