GB2121175A - Liquid level measurement - Google Patents

Abstract

An apparatus for measuring liquid fuel quantities delivered in bulk from calibrated compartments of a road-tanker, comprises at least 25 optical detectors situated in a vertical array on a carrier in a given compartment, the said detectors being adapted to be connected through optical guide means to a light source and to a processing device. The device converts changes in fuel level to quantity delivered. <IMAGE>

Description

SPECIFICATION A method and apparatus for liquid fuel delivery measurement in fuel carrying road-tankers The present invention relates to a method and apparatus for measuring liquid fuel deliveries from fuel carrying road-tankers.

More in particular the invention relates to such measurements in an optical way.

Presently an extensive liquid fuel distribution network exists in many countries in order to provide customers with liquid fuel they need. An example of such liquid fuel is petroleum. Such a distribution may be carried out by road-tankers, which carry and deliver the liquid fuel in bulk at places from which the fuel can be distributed further in relatively small quantities.

It will be clear that it is desirable to obtain an accurate determination of the quantity of liquid fuel, when delivered in bulk from a road-tanker in order to avoid wrong deliveries.

At present it is an accepted and well established way to measure liquid fuel delivered in bulk from a road-tanker by means of diprod, when such deliveries are made from a calibrated compartment of the road-tanker.

A typical petroleum carrying vehicle of say 30,000 litres capacity has 6 compartments of 5,000 litres each and it is necessary for each compartment to be certified with its related diprod. During this process a calibration card is prepared and from this chart a diprod for each compartment is made.

In the calibration of a diprod the blank rod is placed in a jig, saw cuts are then made across the face to the dimensions given in the chart and the related figures are inscribed accordingly. The marking and scribing of a blank rod without the calibration chart would have to be carried out at the time of calibration of the compartment.

It will be clear that the above procedure is very time consuming. Further it is always possible that misreadings of the diprod will take place.

Another disadvantage is that a diprod is not a very suitable instrument to be handled.

Therefore it is an object of the invention to provide an apparatus for measuring liquid fuel quantities which are delivered in bulk by roadtankers, the said apparatus determining accurately and easily the quantities of delivery.

Itls another object of the invention to provide such an apparatus which determines and indicates the said quantities in a very fast way without the risk of misreadings.

It is still another object of the invention to provide a method for measuring liquid fuel quantities delivered by road-tankers in order to provide accurate delivery data.

The invention therefore provides an apparatus for measuring liquid fuel quantities delivered in bulk from a fuel-carrying road-tanker, these deliveries being made from calibrated compartments of the road-tanker, said apparatus comprising at least 25 optical level detectors, each detector comprising a prismatic surface, the said detectors being situated below each other on preselected levels on a carrier over the entire depth of a given compartment, the said detectors being adapted to be connected through optical guide means to a light source and to a processing device, which is adapted to provide the required delivery data.

The invention also provides a method for measuring liquid fuel delivered in bulk from a fuelcarrying road-tanker, these deliveries being made from calibrated compartments of the road-tanker, comprising the steps of measuring and determining the liquid level in the said compartment on preselected levels by means of at least 25 optical detectors, each detector comprising a prismatic surface, and processing the signals thus obtained in order to provide the required delivery data.

In advantageous embodiment of the invention up to 50 optical detectors are used.

A very advantageous embodiment of the invention comprises optical detectors, which are attached to the compartment-wall by using metric pitch rack teeth.

The invention has been based upon the principle that optical detectors, for example prismatic bodies can be used to detect liquid levels in vessels or containers. The physical principle is as follows: light from a suitable light source is passed into the said detectors in any suitable way; if the liquid level in the vessel or the container is above the relevant optical detector the light is reflected internally by the surfaces of the said detector; this reflection can be used to generate a signal in a suitable device such as a photodiode detector; such a signal can be processed further in order to electronically produce the required level data. From the said level data the quantities of delivery can be obtained. Such a conversion as such is known to those skilled in the art and will not be described in detail.

As already indicated in the above, the minimal number of detectors is 25. This number of detectors brings about 200 litre increments in a 5000 litre capacity compartment. It will be clear, that if 50 detectors are used, a liquid level signal can be obtained at every 100 litre increment on a 5000 litre capacity compartment.

The invention will now be described in more detail with reference to the accompanying drawings in which: fig. 1 a and b represent schematically the principle of the invention; fig. 2a and b represent schematically an example of an embodiment of the invention.

Referring now to fig. 1 a and 1 b two suitable light guides such as optical fibres 1, 2 have been represented. A suitable optical sensing body such as a triangular prism 3 has been connected in any suitable way to one end of each of the optical fibres 1, 2. The prism 3 may be attached to a suitable carrier (not shown, for reasons of clarity) which is connected in any way suitable for the purpose to the wall 5 of the compartment of the road-tanker. The compartment itself has not been shown for reasons of clarity. The optical fibre 1 has its other end connected in any suitable way to a light source (not shown, since known per se).

The optical fibre 2 has its other end connected in any suitable way to a suitable processing device, which generates the level data and/or delivery data required. This device may for example consist of an electronic micro-processor with digital display (not shown, since known per se).

The reference numbers 4, 4a respectively indicate the relevant liquid level in the compartment.

According to the invention at least 25 prismatic bodies 3 are situated below each other on predetermined positions on the compartment wall 5. However, for the sake of clarity only one prism has been represented in fig. 1 a and 1 b.

If the liquid level in the compartment is below the prism 3 as shown in fig. 1 a light from the light source (not shown) is passed through the optical fiber 1 from the light source (not shown) into the prism 3. According to known physical principles, which will not be described here in more detail, the light is now reflected internally by the prism surfaces 3a, 3b and will return through the optical fiber 2 which may for example terminate at photodiode detectors (not shown). Such photodiode detectors will generate a signal which may be amplified and processed further in a suitable device such as an electronic microprocessor (not shown). The results may be represented on a digital display (not shown).

However, if the liquid level is above the prism 3 as indicated in fig. 1 b no internal reflection through the fiber 2 will take place since the light will follow a path through the liquid as known to those skilled in the art. This path is indicated by the arrow "A".

It will be appreciated that a single light source can be used for all separate optical fibres.

Fig. 2a, b represent schematically an example of an embodiment of the invention.

Fig. 2a represents a front view of a carrier 6 provided with a rack thread 7 of a suitable pitch for example 1 mm and attached in any suitable way to the wall of a compartment (not shown).

The carrier 6 consists of any material suitable for the purpose and has been provided with a suitable scale indicating level increments 30, 40 .... 70, 80 110,120,130....).

Fig. 2b represents a plan view of an optical detector consisting of a prismatic body 3 provided with an optical fibre 1 from the light source (not shown) and with an optical fibre 2 leading to suitable opto electronics (not shown). The optical detector has its own serrated carrier 10, which has been provided with a rack thread 8 of a suitable pitch, for example 1 mm, on each of its vertical sides so as to match the rack thread 7 on the carrier 6.

As already indicated in the above at least 25 optical detectors are situated below each other on predetermined positions on the carrier 6, only one being shown in fig. 2b for reasons of clarity.

Each detector is retained its position by any means suitable for the purpose, for example a keeper plate (not shown) secured by screws in holes 9 which are spaced at any suitable spacings on the carrier. Other methods of attachment may be used such as spring clips (not shown). It will be appreciated that any suitable light guide, light source, prismatic body and number of light sources can be used. Further it will be appreciated that any number of optical detectors suitable for the purpose can be used provided that this number is at least 25. As already indicated earlier in the specification the number of detectors is dependent on the desired increments. It will also be appreciated that road-tankers having any suitable capacity can be used. Thus, any suitable number of compartments in the road-tanker and compartments having any suitable capacity can be used.

Various modifications of the invention will become apparent to those skilled in the art from the foreging description and accompanying drawings. Such modifications are intended to fall within the scope of the appended claims.

Claims (10)

1. An apparatus for measuring liquid fuel quantities delivered in bulk from a fuel-carrying road-tanker, these deliveries being made from calibrated compartments of the road-tanker, said apparatus comprising at least 25 optical level detectors, each detector comprising a prismatic surface, the said detectors being situated below each other on preselected levels on a carrier over the entire depth of a given compartment, the said detectors being adapted to be connected through optical guide means to a light source and also to a processing device, which is adapted to provide the required delivery data.

2. The apparatus as claimed in claim 1, comprising up to 50 optical detectors.

3. The apparatus as claimed in claim 1 or 2, wherein the said optical detectors carry rack threads so as to match a rack thread on the said carrier.

4. The apparatus as claimed in claim 3, comprising rack threads of 1 mm pitch.

5. The apparatus as claimed in any one of claims 1-4, wherein the said optical detectors are retained in position by a keeper plate.

6. The apparatus as claimed in claim 5, wherein the keeper plate is secured by screws.

7. The apparatus as claimed in claim 5, comprising an attachment by spring clips.

8. A method for measuring liquid fuel quantities delivered in bulk from a fuel-carrying road-tanker, these deliveries being made from calibrated compartments of the road-tanker, comprising the steps of measuring and determining the liquid level in the said compartment on preselected levels by means of at least 25 optical detectors, each detector comprising a prismatic surface, and processing the signals thus obtained in order to

9. Apparatus substantially as described in the processing the signals thus obtained in order to provide the required delivery data.

9. Apparatus substantially as described in the specification and/or represented in fig. 2a, b of the accompanying drawings.

10. Method as claimed in claim 8 substantially as described in the specification by reference to the drawings.