Measuring and testing – Instrument proving or calibrating – Volume of flow – speed of flow – volume rate of flow – or mass...
Patent
1995-05-16
1997-02-25
Raevis, Robert
Measuring and testing
Instrument proving or calibrating
Volume of flow, speed of flow, volume rate of flow, or mass...
G01F 2500
Patent
active
056061099
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to apparatus for determining volume of a liquid, and in particular though not limited to apparatus for determining the deviation of a volume of liquid from a predetermined volume. The invention also relates to a vessel, the volume of which is substantially constant over a range of temperatures.
Apparatus for determining the deviation of a volume of liquid from a predetermined volume is typically used for checking the volumetric measuring accuracy of a dispensing and metering pump, such as, for example, the metering pump of a petrol pump of the type used in the forecourt of a service station. Such apparatus, in general, comprises one or more vessels of known volume. The quantity of liquid whose deviation from a predetermined volume is to be determined is delivered into one of the vessels. A suitable scale is provided for enabling the deviation in the volume of the liquid to be read. These known apparatus suffer from a number of disadvantages. In order to achieve the relatively high degree of accuracy required for determining the deviation of volume, known apparatus tend to require a relatively high degree of operator skill and have significant operational restrictions.
Furthermore, in general, such apparatus are calibrated at a predefined temperature, generally, 20.degree. C. Where the apparatus is used at a temperature other than 20.degree. C. during measuring of the volume of the liquid, the resultant volumes or deviations from a predetermined volume determined from the apparatus will be incorrect. In general, three main factors influence the temperature of the apparatus during measuring, firstly, the temperature of the ambient surrounds of the apparatus, secondly, and in many cases, more importantly, the temperature of the liquid being measured, and thirdly, the thermal response time of the apparatus. This thermal response time varies depending on the thermal conductivity of the material of the apparatus, in other words, the rate at which heat is transferred through the apparatus. For example, where the apparatus is to be used for determining the deviation of a volume of petrol from a predetermined volume, such apparatus, in general, are calibrated at 20.degree. C. It is quite common for the petrol to be at a temperature anywhere from 5.degree. C., and even lower to 20.degree. C. and even higher. Thus, even where an apparatus is stored at a temperature of 20.degree. C., on coming into contact with the petrol, the temperature of the apparatus will be reduced or increased depending on the temperature of the petrol, and this will affect the volume of the apparatus, and in turn the accuracy of the apparatus.
Typical of such apparatus for measuring the deviation in volume of a liquid from a predetermined volume, known heretofore are disclosed in U.S. Pat. Nos. 1,377,577 and 4,928,514. In both cases, the apparatus comprises a container which defines a relatively large hollow interior region for the liquid, and a neck extending upwardly from the container which defines a throat to the hollow interior region of the container. A scale which comprises plus and minus graduations, respectively, above and below a zero datum graduation is mounted in the neck, and enables the deviation of the volume of liquid from the predetermined volume to be measured. The level of the meniscus of the liquid in the throat is read from the scale, and this gives the deviation above or below the predetermined volume. Although, the transverse cross sectional area of the throat in both containers is somewhat less than the transverse cross sectional area of the hollow interior region of the container, it is still relatively large. The accuracy of the results obtained from these apparatus is relatively low. Firstly, because of the relatively large cross sectional area of the throat the vertical distance on the scale corresponding to a unit deviation in volume is relatively small. Thus, without considerable operator skill, inaccuracies may occur when reading the meniscus level from the scale. Secondly, because o
REFERENCES:
patent: 1075025 (1913-10-01), Drautzburg
patent: 1377577 (1921-05-01), Hanson
patent: 1460873 (1923-07-01), Werbeck
patent: 1839809 (1932-01-01), Smith
patent: 2696738 (1954-12-01), Lupfer
patent: 4033190 (1977-07-01), Hudspeth
patent: 4587993 (1986-05-01), Hartl
patent: 4706053 (1987-11-01), Giavarini
patent: 4928514 (1990-05-01), Beaston
Comerford Kieran A.
Hood Oliver S.
Madden John J.
O'Sullivan Niall A.
Sisk Henry B.
Burgee Limited
Raevis Robert
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