DE19720147A1 - Container volume measuring and displaying method - Google Patents

Abstract

The method is used to determine and display the empty and full volumes of a container. The container has rigid walls and can be any desired shape. The container can be closed from the atmosphere or a reference gas pressure. The volume is determined by means of an electronic calculator. The remaining volume (Vo) in the container is calculated by an isothermal volume change when the container is closed. The gas pressure is measured before and after the volume change. The values of the volume change (DV), the initial pressure and the difference in pressure before and after the volume change are input into the computer and the residual volume is calculated according to a given equation and displayed.

Description

The invention relates to a method for determining and displaying the volume of an arbitrarily shaped, opposite to the atmosphere or another reference gas pressure lockable rigid-walled container or the volume of the solid or liquid contents in this container, by means of which the residual volume V ₀ in the container an isothermal volume change DV with the container closed and the gas pressures p ₀ and p measured before and after the volume change by DV (Delta V). In general, the empty volume or the remaining volume of the container is filled with the gas, air, and vapor mixture of the environment. The patent DE 35 40 768 discloses how to determine the remaining volume of this container in an arbitrarily shaped container with solid or liquid filling material and to measure and display the volume of this filling material by differential formation with the total volume.

For reasons of missing characters in the computer, the description below, in the claims, in particular in the mathematical formulas, the Greek character for "Delta" as a difference sign by the one written in bold Letters D are shown (e.g. DV for volume difference or Dp for pressure difference).

After the container has been sealed off from the atmosphere or another reference gas pressure, the resulting gas pressure difference Dp is determined in the gas space or residual volume of the container by a small isothermal volume change DV and entered into an electronic or similarly effective computer for calculating the size of the residual volume V ₀ of the formula:

where the correct sign arises if "only" the "amounts" of the measured values of DV and Dp are entered. In the formula, p _{0 is known} by calibration or is measured in the container gas space after the container has been closed; Dp = p - p ₀ is determined by gas pressure measurement before and after the known volume change DV, DV being known to the computer. By calculating the difference in the computer from V ₀ with the known total volume of the container, the volume of the product is determined and displayed.

The method described above with the approximation formula given above is sufficient for most determinations of empty space and filling volume. In the current development of the electronic computer, however, high measurement accuracy can also be achieved when determining the volume of the product, which can be of great importance, for example, for remaining tank fillings in aircraft, motor vehicles and other vehicles, and also for the exact calibration of any rigid-walled container or would find many applications for volume determination of high-quality contents. According to the invention, the following is proposed:

• 1. For example, a formula (or the same effect) described below for calculating the residual volume V _{0 must be} entered into the electronic computer;
• 2. By means of temperature measurement in the gas space volume V of the container it must be ensured that before and after the volume change DV exactly the same temperature prevails and only after this Temperature match Dp is determined.

Out

with V = V ₀ + DV follows a quadratic equation for V ₀

there

is always negative and

»2 is the value before Root positive. (DV is positive if the remaining volume expands; DV is negative when compressing the remaining volume).

Only then is the volume to be determined, displayed and / or saved by the computer as the difference between the container volume and V ₀ . Finally, it should be pointed out again at point 2 that the value Dp is only entered into the computer after the temperature equality of the residual volume gases and / or vapors or their mixtures in the container before and after the volume change DV.

The method according to the invention is both for exact determination of the empty container volume as well as the container filling volume from the atmosphere or another reference gas pressure lockable, arbitrarily shaped containers with rigid walls suitable.

Claims (1)

Method for determining and displaying the empty volume and the volume of a product of an arbitrarily shaped rigid-walled container that can be locked against the atmosphere or another reference gas pressure by means of an electronic computer, with which the residual volume Vo in the container is changed by an isothermal volume change DV when the container is closed and the gas pressures Po and are measured p is determined before and after the volume change by DV, characterized in that the values DV, p ₀ and Dp = P ₀ - p are entered into an electronic computer and V ₀ by means of this computer according to the formula
is calculated and displayed.