WO2003001148A1

WO2003001148A1 - Method and device for volume measuring

Info

Publication number: WO2003001148A1
Application number: PCT/SE2002/001114
Authority: WO
Inventors: Leif Henryson
Original assignee: Viken Investments Limited
Priority date: 2001-06-26
Filing date: 2002-06-10
Publication date: 2003-01-03
Also published as: SE0102275D0; SE519299C2; SE0102275L

Abstract

Method of measuring the volume of a bakery product (2), comprising the stages that an ultrasonic transmitter (10) for measuring destance is held at a known distance from a reference point (R) in the bakery product throughout the measurement, a relative movement is created between the bakery product (2) and the ultrasonic transmitter (10) so that essentially the entire surface of the bakery product is struck successively during the relative movement by a measuring signal from the ultrasonic transmitter, the distance for the path of the measuring signal from the ultrasonic transmitter (10) to the surface of the bakery product 82) is measured repeatedly during the relative movement, the volume of the bakery product is calculated with the aid of the distances measured and the distance from the ultrasonic transmitter to the refeence point in the bakery product. According to the invention, the distance for the path of the measuring signal between the ultrasonic transmitter (10) and the surface of the bakery product (2) is set up to longer than the shortest distance between the ultrasonic transmitter and the surface of the bakery product in each given position of the relative movement. A device for executing the method is also shown.

Description

METHOD AND DEVICE FOR VOLUME MEASURING

TECHNICAL FffiLD

The present invention relates to a method for measuring the volume of a bakery product, comprising the stages that:

- an ultrasonic transmitter for measuring distance is held at a known distance from a reference point in the bakery product throughout the entire measurement,

- a relative movement is created between the bakery product and the ultrasonic transmitter so that essentially the entire surface of the bakery product is struck successively during the relative movement by a measuring signal from the ultrasonic transmitter,

- the distance of the measuring signal's path from the ultrasonic transmitter to the surface of the bakery product is measured repeatedly during the relative movement,

- the volume of the bakery product is calculated with the aid of the distances measured and the distance from the ultrasonic transmitter to the reference point in the bakery product. The invention also relates to a device for executing the method.

PRIOR ART AND PROBLEMS In the industrial production of bakery products, such as loaves, rolls, cakes etc., it is important to be able to carry out spot tests on the quality of the bakery products. One such important measurement consists of the volume of the bakery product in relation to its weight. The weight of the bakery product is measured easily by means of a weighing machine. However, the volume can be harder to measure considering the irregular appearance that bakery products often have. Especially if the measurement is to be nondestructive and one does not wish to immerse the bakery product in a liquid or other medium, the problem exists of being able to carry out non-destructive testing in a repeatable, precise and standardized manner. Another occasion when it is desired to carry out volume measurement of a bakery product is when the quality of a raw material for the bakery product, e.g. flour, is to be determined by means of a standardized baking test. A satisfactorily functioning method and a satisfactorily functioning device for measurement of this kind of the volume of a loaf is presented in WO 95/22744, ultrasound being utilized in this case. Volume measurements carried out according to the principle described therein are both precise and repeatable and also well suited to use in industrial bakeries or the like. However, there is room for a certain improvement in the method and device according to WO 95/22744. In the case of ultrasonic measurements, the ultrasonic transmitter must namely be arranged at a certain minimum distance from the object that is to reflect the ultrasonic signal, owing to the natural resonance of the ultrasonic transmitter. It has proved to be the case that a certain minimum distance must normally be maintained, e.g. around 4- 15 cm at least depending on the design of the ultrasonic transmitter, between the ultrasonic transmitter and the object that is to reflect the ultrasonic signal, in order to avoid the effects of the ultrasonic transmitter's natural resonance. In the method and device according to WO 95/22744, a relative movement is created between the loaf and the ultrasonic transmitter so that essentially the entire surface of the loaf is struck successively during the relative movement by the measuring signal from the ultrasonic transmitter. This means that the entire device must be dimensioned so that said minimum distance between the ultrasonic transmitter and the loaf or the bakery product is maintained throughout the relative movement. Due to this, the device becomes unnecessarily large and unwieldy.

BRIEF ACCOUNT OF THE INVENTION

The object of the present invention is to offer a method and a device for measuring the volume of a bakery product by means of ultrasound precisely, repeatably and in a manner well suited to industrial requirements, h particular, the object of the invention is to offer a device and a method for using the device, which device is dimensionally adapted to be small and neat at the same time as a certain minimum required distance can be maintained between the ultrasonic transmitter and the bakery product that shall reflect the ultrasonic signal. This object is achieved by means of the method according to claim 1 and the device according to claim 6.

The problem is thus solved according to the invention in that the distance for the path of the measuring signal between the ultrasonic transmitter and the surface of the bakery product is set up to be longer than the shortest distance between the ultrasonic transmitter and the surface of the bakery product in each given position of the relative movement. Due to the fact that the path of the measuring signal is deflected so that it is longer than the shortest distance between the ultrasonic transmitter and the surface of the bakery product, the path can be located in such a way that its extension lies within the device, without extra space having to be used for the path of the measuring signal, which accordingly has to be a certain minimum distance.

According to an aspect of the invention, said distance for the path of the measuring signal is extended by means for deflecting the measuring signal, which means preferably consist of one or more reflectors and even more preferredly of one or more angled sheets.

According to another aspect of the invention, this reflector or these reflectors is/are arranged so that it/they retains/retain the same position and direction in relation to the ultrasonic transmitter throughout the relative movement.

According to yet another aspect of the invention, said distance for the path of the measuring signal is set up to be 4-15 cm, preferably 5-12 cm and even more preferredly 5-10 cm longer than the shortest distance between the ultrasonic transmitter and the surface of the bakery product.

Other aspects of the method and device according to the invention correspond entirely to what is described in WO 95/22744, for which reason this text is hereby incorporated in the present description through reference. DETAILED ACCOUNT OF THE INVENTION

The invention will be described below with reference to the drawings, in which:

Fig. 1 shows a diagrammatic side view of an embodiment of a device for measuring the volume of a bakery product according to the invention, Fig. 2 shows a diagrammatic side view, which is partly in block diagram form and which shows the device in Fig. 1 seen from a different direction, Fig. 3 shows, seen in side view, an ultrasonic transmitter that is mounted on an arm together with a means of deflecting the ultrasonic signal, Fig. 4 shows Fig. 3 seen from a different direction.

In the detailed account of the invention, the invention shall be exemplified for the sake of simplicity by the volume measurement of bread. However, it shall be understood that the invention is equally applicable to other bakery products.

The bread volume meter shown in Fig. 1 comprises a holder 1 for carrying a loaf 2, which is shown by dashed lines in Fig. 2. The holder 1 is fitted on a mounting 3, which is supported rotatably in a base 4. Fitted to the base 4 is a first motor 5, λvhich has an output shaft 6, which via a belt 7 can cause the mounting 3 to rotate. On the base 4 is also a stand 8, on which an arm construction 9 with a first vertical arm 9a and a second transverse arm 9b are mounted movably. "Vertical" arm 9a here is taken to mean an arm that can be turned in a vertical plane. An ultrasonic transmitter 10 and an angled sheet 22 are fitted to one end of the transverse arm 9b. The ultrasonic transmitter 10 contains a transmitter and a receiver. The transmitter emits a well-focused beam with a focal distance of 10 cm, for example. The operating frequency can advantageously lie e.g. in the range 100 kHz to 1000 kHz, but other frequencies are also conceivable. The angled sheet 22 forms a reflector for a measuring signal that is emitted by the ultrasonic transmitter 10.

The transverse arm 9b can be fastened in various positions along the length of the vertical arm, e.g. by using a fastening groove 11 in the vertical arm 9a or in an equivalent way. Adjustment of the arm construction 9 to different sizes of bakery products can hereby be undertaken.

A second motor 12 is also fitted in the base 4. This motor 12 has an output shaft 13, which drives a belt 14, which in turn drives a shaft 15, which is supported in the stand 8 and on which the arm construction 9 is fitted. The arm construction 9 is set up to guide the transmitter 10 in a semi-circular movement around a reference point R, which is formed by the point of intersection between the geometrical longitudinal axis LI and L2 around which the holder 1 and the arm construction 9 respectively are turned. The transmitter 10 is thus located at a constant distance from the reference point R throughout the movement.

The device also comprises the angle sensors 16 and 17 for measuring the angle of rotation of the holder 1 and the angle of rotation of the arm construction 9 respectively. The two angle sensors 16 and 17 are, like the ultrasonic transmitter 10, connected to a calculating organ 18, preferably a personal computer, with a keyboard 19 and screen 20. A temperature sensor 21, for measuring the temperature at which the volume measurement is carried out, is preferably also connected to the calculating organ 18.

Figs. 3 and 4 show a hypothetical embodiment of the transverse arm 9b and the ultrasonic transmitter 10 and angled sheet 22. The transverse arm 9b here also comprises a leg-shaped fastening part 23 for attachment to the vertical arm 9a in Fig. 1 and 2. The angled sheet 22 is expediently formed in metal, preferably steel and at best stainless steel. The angled sheet 22 can be arranged fixedly on the transverse arm 9b. In a first part 22b, the extension of the angled sheet 22 initially follows the direction of an ultrasonic pulse that is emitted by the transmitter 10. After a certain distance from the ultrasonic transmitter, the angled sheet 22 is angled off into a second part 22a that has an angle α in relation to the first part 22b. In the preferred embodiment, the angle is 135°. If the ultrasonic transmitter 10 has another initial direction or if two or more reflectors are used, however, then other angles may be appropriate. In the embodiment shown, the distance from the ultrasonic transmitter to a point of impact of the measuring signal on the second, angled part 22a of the angled sheet 22 is the distance that the measuring signal's path is extended according to the invention. The angled part 22a can if necessary be displaceable in relation to the first part 22b, or the entire angled sheet 22 or the transverse arm 9b can also be displaceable in relation to the vertical arm 9a, so that the position of the angled part 22a can be set exactly above the reference point R.

The function of the volume meter shown shall be described below. A loaf 2, the volume of which is to be measured, is placed on the holder 1 and its height is set so that the centre of the loaf lies roughly at the reference point R. Furthermore, the transverse arm 9b is placed in a suitable position for the current loaf on the vertical arm 9a. Thanks to the angled sheet 22, the arm 9b can be placed much closer to the surface of the loaf 2. Now the distance from the transmitter 10 to the reference point R is determined. The motors 5 and 12 are started so that the loaf 2 is caused to rotate around the longitudinal axis LI at a constant angular velocity and the arm construction 9 with the transmitter 10 and angled sheet 22 is caused to swing around the longitudinal axis L2 at a constant angular velocity. In the preferred embodiment, the angular velocity of the holder 1 and thus the loaf 2 is significantly higher than the angular velocity of the arm construction 9.

The calculating organ 18 directs the ultrasonic transmitter 10 to sample the distance to the surface of the loaf 2 at a constant frequency. The ultrasonic transmitter 10 and angled sheet 22 are best arranged so that a measuring signal, i.e. an ultrasonic pulse, from the ultrasonic transmitter 10 is initially emitted perpendicular to the vertical plane in which the vertical arm 9a moves, in order then to be deflected 90° by means of the angled sheet 22, so that the measuring signal, after it has left the angled sheet 22, runs parallel to the vertical plane in which the vertical arm 9a moves, in the direction of the reference point R. However, the measuring signal is reflected against the surface of the loaf 2 and returns via the angled sheet 22 to the ultrasonic transmitter 10. The distance is determined from the time between the transmission of the measuring signal and receipt of the same in the ultrasonic transmitter 10, with reference to the temperature that is provided by the temperature sensor 21. During a measurement, the transmitter 10 is rotated approx. 170° around the reference point R, while the holder 1 rotates a large number of revolutions. Essentially the entire surface of the loaf will be scanned successively in this way by pulses from the transmitter 10 during a measurement, and a large number of distance values are obtained. On each sampling of the distance to the surface of the loaf, the angles of rotation of the holder 1 and the arm construction are also determined by means of the angle sensors 16 and 17. The angle values are supplied together with the distance signal from the ultrasonic transmitter 10 as input signals to the calculating organ 18.

The volume is calculated in the following manner in the calculating organ 18. For each sampling by the ultrasonic transmitter 10, a corresponding distance to the surface of the loaf is determined. Each distance corresponds to a measuring point, the coordinates of which are provided by the angle values of the angle sensors 16 and 17. Each distance thus determined to the surface of the loaf is subtracted from the known distance between the transmitter 10 and the reference point R, a loaf radius being obtained for each measuring point. A partial volume is then calculated for each measuring point, which volume is based on the corresponding loaf radius, the spread of the ultrasonic pulses and the angle of rotation of the holder. The total volume of the loaf is obtained by totalling up the partial volumes calculated. The result is presented on the screen 20.

Since the loaf rotates at a constant angular velocity and the distances are collected at a constant frequency, the relative surface angular velocity between the transmitter 10 and the loaf 2 will vary depending on the angle of rotation of the arm construction 9, which angle is compensated for in that each partial volume is weighted by means of the corresponding angle of rotation for the holder 1.

The invention is not restricted to the embodiments described above, but can be varied within the scope of the following claims. The transmitter and bakery product do not have to be moved for example in the manner indicated above in relation to one another. One variant is that the transmitter can be fixed and the loaf rotated in the same way as the embodiment described above, but moved at the same time in a vertical direction. Other variants are also conceivable. The important thing is that the transmitter and the loaf are moved in such a way in relation to one another that essentially the entire surface of the bakery product is scanned by means of a measuring signal from the transmitter and that the distance between the transmitter and a reference point in the bakery product is known. When using several deflectors/reflectors for the measuring signal, the initial direction of the measuring signal can be different to that shown in the drawings. The essential factor is that the measuring signal, following the deflections, is directed towards the reference point R. Following the deflections, it runs preferably parallel to the plane in which the vertical arm 9a moves, or seen in another way parallel to the plane in which the transmitter 10 moves.

Claims

1. Method for measuring tlie volume of a bakery product (2), comprising the stages mat:

- an ultrasonic transmitter (10) for measuring distance is held at a known distance from a reference point (R) in the bakery product throughout the entire measurement,

- a relative movement is created between the bakery product (2) and the ultrasonic transmitter (10) such that essentially the entire surface of the bakery product is struck successively during the relative movement by a measuring signal from the ultrasonic transmitter,

- the distance for the path of the measuring signal from tl e ultrasonic transmitter (10) to the surface of the bakery product (2) is measured repeatedly during the relative movement,

- the volume of tlie bakery product is calculated with tl e aid of the distances measured and the distance from the ultrasonic transmitter to the reference point in the bakery product, characterized in that the distance for the path of the measuring signal between tlie ultrasonic transmitter (10) and the surface of the bakeiy product (2) is set up to be longer than the shortest distance between the ultrasonic transmitter and tlie surface of the bakery product in each given position of the relative movement, said distance for the path of the measuring signal being extended by means (22) for deflecting the measuring signal, which means consist of one or more reflectors, which reflector is arranged or which reflectors (22) are arranged so that it or they retain the same position and direction in relation to tl e ultrasonic transmitter (10) throughout the relative movement.

2. Method according to claim 1, characterized in that said means (22) for deflecting tlie measuring signal consist of one or more an ed sheets.

3. Method according to any of the above claims, characterized in that said distance for the path of the measuring signal is disposed to be 4-15 cm, preferably 5-12 cm and even more preferredly 5-10 cm longer than said shortest distance between the ultrasonic transmitter (10) and the surface of the bakery product (2).

4. Method according to claim 2, characterized in that only one angled sheet (22) is used and that this has a first part (22b) and a second, reflecting part (22a) that is angled 135° in relation to the first part (22b).

5. Device for measuring the volume of a bakery product (2), comprising an organ (1) for supporting the bakery product, an ultrasonic transmitter (10) for measuring the distance for a measuring signal between the ultrasonic transmitter and the surface of the bakery product, which ultrasonic transmitter is arranged so that it is located throughout the measurement at a known distance from a reference point (R) on or close to the supporting organ (1), so that the reference point lies in the bakery product, driving organs (5, 12) for achieving a relative movement between the ultrasonic transmitter (10) and the supporting organ (1), which relative movement is such that essentially the entire surface of the bakery product (2) is struck successively by said distance measuring signal from the ultrasonic transmitter (10) during the relative movement, and a calculating organ (18), which is disposed to receive information about the relative movement and distances measured by the ultrasonic transmitter (10) as input signals and which is disposed to calculate the volume of the bakery product with the aid of the input signals and said known distance from the ultrasonic transmitter (10) to the reference point (R), characterized in that the distance for the path of the measuring signal between the ultrasonic transmitter (10) and the surface of the bakery product (2), when the bakery product is on the supporting organ (1), is set up to be longer than the shortest distance between the ultrasonic transmitter (10) and the surface of the bakery product (2) in each given position of the relative movement, said distance for the path of the measuring signal being extended by means (22) for deflecting the measuring signal, which means consist of one or more reflectors, which reflector or which reflectors (22) retain the same position and direction in relation to the ultrasonic transmitter (10) throughout the relative movement.

6. Device according to claim 5, characterized in that said means (22) for deflecting the measuring signal consist of one or more angled sheets.

7. Device according to any of claims 5-6, characterized in that said distance for the path of the measuring signal is set up to be 4-15 cm, preferably 5-12 cm and even more preferredly 5-10 cm longer than said shortest distance between the ultrasonic transmitter (10) and the surface of the bakery product (2).

8. Device according to claim 6, characterized in that only one angled sheet (22) is provided and that this has a first part (22b) and a second, reflecting part (22a) that is angled 135° in relation to the first part (22b).