Pasch, Lothar (Pr. Johan Frisohof 34, WV Terborg, NL-7061, NL)
| 1. | Measuring station for determining the degree of filling of a container having a tillable volume, comprising: closing means for the airtight closing off of a volume that comprises the tillable volume of the container, pressure measuring means that can be brought into contact with the volume, and a drive means for driving the airtight closing off of the volume by the closing means, and for changing the volume with a known volume change. |
| 2. | Measuring station according to claim 1 , wherein the drive means is adapted for consecutively ' closing off the container airtight and subjecting the volume to a known volume change. |
| 3. | Measuring station according to claim 1 or 2, wherein the drive means is adapted for in one continuous motion closing off the container airtight and subjecting the volume to a known volume change. |
| 4. | Measuring station according to any one of the preceding claims, wherein the closing means for closing off the volume airtight can be brought into contact with the container. |
| 5. | Measuring station according to any one of the preceding claims, wherein the closing means comprise a stamp or lid suitable for being placed into airtight contact with an opening in the container. |
| 6. | Measuring station according to any one of the preceding claims, comprising prebiassing means for keeping the volume or the container closed off airtight. |
| 7. | Measuring station according to claim 6, wherein the prebiassing means comprise a spring. |
| 8. | Measuring station according to any one of the preceding claims, wherein the closing means comprise resilient sealing means. |
| 9. | Measuring station according to claim 8, wherein the sealing means comprise rubber or a similar material. |
| 10. | Measuring station according to claim 5 and 8 or 9, wherein the sealing means are disposed at a side of the stamp or lid in order to be placed against the container. |
| 11. | 1 1. |
| 12. | Measuring station according to claim 10, wherein the sealing means are disposed on the stamp or lid according to a contour, preferably of an upper edge of the container. |
| 13. | Measuring station according to any one of the preceding claims, comprising a hollow cylinder having a piston therein which is movable with respect to and in the longitudinal direction of the hollow cylinder, wherein the cylinder comprises a portion of the volume that is subjected to a known volume change due to the movement of the piston. |
| 14. | Measuring station according to claim 12, wherein at least one stop is disposed in the hollow cylinder, which stop limits the freedom of movement of the piston, preferably over a set distance. |
| 15. | Measuring station according to claim 12 or 13, wherein the piston is actively connected with the drive means. |
| 16. | Measuring station according to any one of the claims 1214, wherein the hollow cylinder is actively connected with the closing means. |
| 17. | Measuring station according to claim 1 5, wherein an end of the hollow tube or cylinder is attached to the closing means. |
| 18. | Measuring station according to claim 15 or 16, wherein a through hole has been made through the closing means to which hole the hollow tube or hollow cylinder connects. |
| 19. | Measuring station according to any one of the claims 1217, wherein the prebiassing means prebias the hollow cylinder in the direction of the container. |
| 20. | Measuring station according to any one of the preceding claims, wherein the drive means move the closing means along a straight line. |
| 21. | Measuring station according to any one of the preceding claims, wherein the drive means comprise a pneumatic or hydraulic drive cylinder. |
| 22. | Measuring station according to claim 20 and any one of the claims 1219, wherein a connecting rod of the pneumatic or hydraulic drive cylinder is connected with the piston. |
| 23. | Measuring station according to any one of the preceding claims, wherein the pressure measuring means are suitable for comparing a measured pressure to a predetermined reference pressure. |
| 24. | Measuring station according to any one of the preceding claims, suitable for processing foodstuff. |
| 25. | Measuring station according to any one of the preceding claims, suitable for determining a quantity of dough in a bread pan. |
| 26. | Production line comprising a measuring station according to any one of the preceding claims. |
| 27. | Method for determining the degree of filling of a container having a fillable volume, comprising the following steps: the airtight closing off of a volume that comprises the fillable volume < of the container; changing the volume and determining a related pressure change. |
| 28. | Method according to claim 26, wherein the volume is closed off airtight and the volume is subsequently subjected to a known volume change. |
| 29. | Method according to claim 26 or 27, wherein the airtight closing off of the volume and changing the volume is carried out by one drive assembly. |
| 30. | Method according to any one of the preceding claims 2628, wherein the pressure change is compared to a known reference pressure change. |
| 31. | Method according to any one of the preceding claims 2629, applied for determining the degree of filling of a container with foodstuffs. |
| 32. | Method according to any one of the preceding claims 2630, applied for determining the degree of filling of a container, wherein the filling comprises heterogeneously divided portions or units. |
| 33. | Method according to any one of the preceding claims 2631 , applied for determining the degree of filling of a bread pan with dough portions. |
| 34. | Measuring station for determining the degree of filling of a container having a tillable volume, comprising: closing means for the airtight closing off of a volume that comprises the tillable volume of the container, pressure measuring means that can be brought into contact with the volume, and a drive means for both driving the closing means and for changing the volume with a known volume change. |
| 35. | Measuring station according to claim 33, wherein the drive means is adapted for consecutively driving the closing means and changing the volume. |
| 36. | Measuring station according to any one of the claims 1 24, or claim 33 or 34, wherein the closing means comprise a closing wall, wherein a wall section thereof is movable with respect to the other sections of the closing wall for changing the volume. |
| 37. | Measuring station provided with one or more of the characterising measures described in the attached description and/or shown in the attached drawings. |
| 38. | Method comprising one or more of the characterising steps described in the attached description and/or shown in the attached drawings. |
The invention relates to a measuring station for determining the degree of filling of a container having a tillable volume.
The invention particularly relates to a measuring station for determining the degree of filling of a container having a fillable volume, wherein the filling comprises a number of individual units or portions of a certain size, or a heterogeneous filling.
Such measuring stations usually are incorporated into a production line, for instance a production line including a dosing machine at which a number of dough portions are put into a bread pan. In this example the measuring station checks whether sufficient, or in any case not too many dough portions have been put into the bread pan. To that end the contents of the bread pan can be checked by (opto-)electronically scanning the height of the contents of a filled bread pan from above, so that based on the height of the all the dough portions the degree of filling of the bread pan can be derived. A drawback of such an (opto- )electronic height measurement, however, is that it is unreliable, as the heterogeneously divided dough portions may partially lie on and over each other wile leaving intermediate spaces free which from above are difficult to perceive. Moreover, the necessary electronic equipment is technically complex and costly as a result.
It is an object of the invention to provide a measuring station for determining the degree of filling of a container having a certain tillable volume, with which the degree of filling of the container can be reliably determined.
It is a further object of the invention to provide a measuring station for determining the degree of filling of a container having a certain tillable volume, with which the degree of filling of the container can easily be determined.
It is a further object of the invention to provide a measuring station that has a simple structure and is cheap as a result for determining the degree of filling of a container having a certain tillable volume.
According to a first aspect the invention provides a measuring station for determining the degree of filling of a container having a tillable volume, comprising: closing means for the airtight closing off of a volume that comprises the tillable volume of the container, pressure measuring means that can be brought into contact with the volume, and a drive means for driving the airtight closing off of the volume by the closing means, and for changing the volume with a known volume change.
An advantage of the measuring station according to the invention is that the degree of filling of the container can be derived from a pressure change caused by the known volume change of the volume measured by the pressure measuring means, wherein the measuring station can be simple as regards structure due to the combined action of the drive means. The pressure change here depends on the volume taken up by the filling of the container. In case of a known and constant homogeneous density of the filling, even the mass of a (heterogeneously divided) filling can be derived from the pressure change.
The volume change will be the same as much as possible per measurement when the drive means is adapted for consecutively closing off the container airtight and subjecting the volume to a known volume change.
The drive of the drive means can be designed simple when the drive means is adapted for in one continuous motion closing off the container airtight and subjecting the volume to a known volume change.
In a simple embodiment the closing means for closing off the volume airtight can be brought into contact with the container.
For a proper closing off of the container the closing means comprise a stamp or lid suitable for being placed into airtight contact with an opening in the container. With respect to the container they can be brought into contact with the container from above, particularly with an upper edge of the container.
During volume change the drive means can be substantially used for effecting the volume change when the measuring station comprises pre-biassing means for keeping the volume or the container closed off airtight.
In a simple embodiment the pre-biassing means comprise a spring. When the closing means comprise resilient sealing means, an airtight contact between the sealing means and the container can be effected despite small deviations or dents in the container.
Preferably the sealing means comprise rubber or a similar material, as in combination with a container that usually retains its shape this results in proper sealing properties.
In an efficient embodiment the sealing means are disposed at a side of the stamp or lid in order to be placed against the container.
The sealing means are efficiently used when the sealing means are disposed on the stamp or lid according to a contour, preferably of an upper edge of the container.
Preferably the measuring station comprises a hollow cylinder having a piston therein which is movable with respect to and in the longitudinal direction of the hollow cylinder, wherein the cylinder comprises a portion of the volume that is subjected to a known volume change due to the movement of the piston. An advantage thereof is that such parts are commonly available and cheap as a result.
The change of the first or second volume can be set when at least one stop is disposed in the hollow tube or hollow cylinder, which stop limits the freedom of movement of the piston, preferably over a set distance. When stopped, it is moreover possible to let the hollow tube or cylinder move along with the piston in at least one direction.
In a simple embodiment the piston is actively connected with the drive means. When the closing means are actively connected to the closing means via the hollow tube or hollow cylinder, the closing means can be moved along with the hollow cylinder of hollow tube by the stops in the hollow cylinder or hollow tube.
In a simple embodiment an end of the hollow tube or cylinder is attached to the closing means.
A fluent connection between the hollow tube or hollow cylinder is very direct when a through-hole has been made through the closing means to which hole the hollow tube or hollow cylinder connects.
The closing means in the direction of the container are pre-biassed and thus kept in contact with the container when the pre-biassing means pre-bias the hollow tube or hollow cylinder in the direction of the container.
In a simple embodiment the drive means can move the closing means along a straight line.
A movement of the closing means, particularly a movement of the closing means in a straight line can be effected when the drive means comprise a pneumatic or hydraulic drive cylinder.
In an embodiment that is simple as regards structure a connecting rod of the pneumatic or hydraulic drive cylinder is connected with the piston.
When the pressure measuring means are suitable for comparing a pressure to a pre-determined reference pressure, it can easily be determined whether a container is filled too much or too little, so that an incorrectly filled container can be approved of or rejected prior to carrying out a follow-up treatment.
Preferably the measuring station is suitable for processing foodstuff.
Preferably the measuring station is particularly suitable for determining a quantity of dough in a bread pan.
The invention furthermore relates to a production line comprising the measuring station discussed above.
According to a further aspect, the invention relates to a method for determining the degree of filling of a container having a certain tillable volume.
The invention particularly relates to a method for determining the degree of filling of a container having a certain tillable volume, wherein the filling comprises a number of individual units or portions having a certain size, or is heterogeneously divided.
Such methods are usually carried out in a production line, for instance in a production line having a dosing machine for dough as described in the previous example, wherein the degree of filling is (opto- )electronically determined. A drawback of such a method with electronic measurement is, however, that it is unreliable, as the heterogeneously divided dough portions may partially lie on and over each other while leaving intermediate spaces free which from above are difficult to perceive.
It is an object of the invention to provide a reliable method for determining the degree of filling of a container having a certain tillable volume. It is a further object of the invention to provide a method for determining the degree of filling of a container having a certain tillable volume for a heterogeneously divided filling.
At least one of the above-mentioned objects is achieved, according to a further aspect, using a method according to the invention for determining the degree of filling of a container having a tillable volume, comprising the following steps: - placing closing means for the airtight closing off of a volume that comprises the tillable volume of the container; - changing the volume and determining a related pressure change.
An advantage of the method according to the invention is that the degree of filling of the container can be derived from the pressure change caused by the known volume change. Particularly a heterogeneously divided filling in this case does not affect the measuring result, as the degree of filling is determined by the residual volume of the container that is left in addition to the filling. The pressure change in this case depends on the volume taken up by the filling of the container. In case of a known and constant homogeneous density of the filling, even the mass of the (heterogeneously divided) filling can be derived from the pressure change.
For a reliable volume change the volume is closed off airtight and the volume is subsequently subjected to a known volume change.
The method is simple when the airtight closing off of the volume and changing the volume is carried out by one drive assembly.
When the pressure or pressure change is compared to a known reference pressure or reference pressure change, it can easily be determined whether a container is filled too much or too little, so that an incorrectly filled container can be approved of or rejected prior to carrying out a follow-up treatment.
As the filling of the container is not contacted during measuring the method can be applied for determining the degree of filling of a container with foodstuffs.
The method can particularly be applied for determining the degree of filling of a container, wherein the filling comprises heterogeneously divided portions or units, particularly of a bread pan with dough portions.
The invention will be elucidated on the basis of a number of exemplary embodiments shown in the attached drawings, in which:
Figure 1 shows a view in perspective of a measuring station according to the invention; and
Figures 2A, 2B and 2C show a cross-section of the measuring station according to figure 1 , in three different positions. The position in figure 2A in this case corresponds to the position in figure 1 .
Figure 1 shows a measuring station 1 for determining the degree of filling of a bread pan 5 filled with a number of dough portions 6. The bread pan 5 is part of a number of bread pans 5 in a row that are supplied and discharged one by one by a conveying mechanism that is not shown to a measuring station in order to be measured.
The measuring station 1 according to figure 1 has a frame 2 having a vertical column 3 and a hollow cross girder 4 mounted transverse thereto. The cross girder 4 is a U-shaped angle section that is open at the rear side that is not shown. By means of two flanges 7 the cross girder 4 is fixed to an upper end of the column by means of four bolts 8 that have been inserted through four holes 9 in the two flanges 7.
The measuring station 1 according to figure 1 has a metal stamp 15 which via a movement mechanism 17 is connected to the cross girder 4. The stamp 15 has a rectangular level plate 18 having raised edges 19 around it. The raised edges 19 are integrally formed at the level plate 18 by means of turning. The raised edges 19 ensure rigidity of the plate 18.
At a bottom side (20, see figures 2A-2C) of the rectangular level plate 18 (in the direction of the bread pans 5) a rubber sealing 21 is disposed. Said sealing 21 is a rubber strip which according to the contour of an upper edge 16 of the bread pan 5 is attached to the rectangular level plate 18 along the circumference of the rectangular level plate 18. As a result the stamp 1 5 is able to close off the bread pan 5 airtight from above.
At an upper side 22 of the stamp 1 5 a hollow round cylinder 23 is attached in the centre of the plate 18. At an end opposite the stamp the cylinder 23 is closed off by an end plate 24. There is a round piston 25 in the hollow cylinder 23, which piston is connected to a connecting rod 28 of a pneumatic drive cylinder 27 which connecting rod is inserted through a hole (14) in the end plate 24. Between the end plate 24 and the cross girder 4 there is a spring 26 around the connecting rod 28 which spring pre-biasses the stamp 1 5 via the end plate 24 and the hollow cylinder 23 in the direction of the bread pan 5. The stamp 15 at one side abuts the pillar guides 49 at the column 3, as a result of which rotation of the stamp 15 about the connecting rod is blocked. When instead of a round cylinder and piston an unround cylinder, such as a square cylinder having a similarly shaped piston, is used, the pillar guide 49 is unnecessary. The drive mechanism 17 will be further elucidated below in figure 2A.
A hose 29 is attached to the stamp 15 by means of a connecting nipple 31 which hose connects the stamp to an electronic pressure gauge 30. Via a hole through the plate 18 the nipple 31 brings air at the bottom side 20 of the stamp 15 in flowing connection with the hose 29 and thus with the pressure gauge 30. The pressure gauge 30 is connected to a control unit that is not shown with which also the pneumatic drive cylinder 27 is controlled.
Figure 2A shows a cross-section of the device according to figure 1 . As shown in figure 2A a housing 34 of the pneumatic drive cylinder 27 is attached to an upper side 10 of the cross girder 4 by means of bolts 35. The connecting rod 28 of the pneumatic drive cylinder 27 in this case protrudes vertically through the holes 12 and 13 in the upper side 10 and the bottom side 1 1 , respectively, of the hollow cross girder 4. The connecting rod 28 of the pneumatic cylinder 27 in its extension in the direction of its centre line is connected to the piston 25 via a coupling piece 33. The connecting rod 28 and the coupling piece 33 are attached to each other with a threaded connection 37 that is known per se.
Between the spring 26 and the connecting rod 28, and in their extension the coupling piece 33 a spring guide 39 is attached around the connecting rod 37 and the coupling piece 33, on the end plate 24 of the hollow cylinder 23. The spring guide 39 prevents the spring 26 from buckling or deforming in a direction transverse to the connecting rod or the coupling piece 33.
The piston 25 is attached to the coupling piece 33 with a threaded end 46 at one end of the coupling piece 33. The threaded end 46 is in this case inserted through a hole 45 in the piston 25, the piston 25 being secured around the threaded end 46 with a bolt 47.
Along its circumferential wall the piston 25 is provided with a sealing ring 36 that has been disposed in a groove in the circumferential wall of the cylinder 36. The sealing ring 36 partially projects above the circumferential wall and abuts the cylinder 23. Between the piston 25 and the end plate 24 of the hollow cylinder 23 a filler ring 33 is attached to the piston around the coupling piece 33, which filler ring prevents the piston from contacting the end plate 24. As a result de- aeration holes 32 are kept free which have been disposed in the hollow cylinder 23. The de-aeration holes 32 prevent that air pressure is built up in the cylinder 23 between the piston 25 and the end plate 24, when the piston 25 moves with respect to the cylinder 23.
At its bottom side the hollow cylinder 23 is attached to the hollow plate 18, wherein a flow-through opening is formed through the plate 18 through which air in a first space 40 in the cylinder 23 under the piston 25 can be pressed out of the cylinder 23 by the piston 25.
Figures 2A, 2B and 2C show consecutive steps carried out by the measuring station in order to determine how much dough there is in the bread pan 5 that has been placed under the stamp 15 of the measuring station 1 .
In a first position of the piston 25 and the stamp 1 5, as shown in figure 2A, the connecting rod 28 of the pneumatic drive cylinder 27 is fully retracted, as a result of which the piston 25 is in its highest position as indicated by means of dotted line 42. In this case the piston 25 is in abutment with the end plate 24 via the filler ring 38, also due to the pre-biassing in the spring 26. The stamp 15 is in this case high enough in order to be able to place the bread pan 5 under the stamp 15. After placing the bread pan 5 under the stamp 1 5, as shown in figure 2B, the pneumatic drive cylinder 27 is actuated via the control unit, as a result of which the piston 15 via the connecting rod 28 moves in the direction of the bread pan 5 to a centre position as shown by means of dotted line 43. Due to the pre-biassing of the spring 26 the piston 25 remains in contact with the end plate 24 of the hollow cylinder 23 via the filler ring 38, until the rubber sealing 21 comes into contact with the upper edge 16 of the bread pan 5. Due to the pre-biassing in the spring 26 the stamp 15 is pressed firmly onto the upper edge 16 of the bread pan 5, as a result of which the bread pan 1 5 is closed off airtight by the stamp 15. In addition the first space 40 under the piston 25 comes into flowing connection with a free second space 41 around the dough portions 6 in the bread pan 5 via the flow-through opening 48.
Subsequently, as shown in figure 2C, the piston 25 is pressed in the direction of the bread pan 5 by the pneumatic drive cylinder 27 into a lowermost position as shown by means of dotted line 44. The lowermost position 44 of the piston 25 is in this case determined by the ultimate position of the pneumatic drive cylinder 27. However, stops may also have been arranged in the hollow cylinder 23 itself, as a result of which the lowermost position of the piston 25 in the hollow cylinder 23 is set.
Due to the movement of the piston 25 from the centre 43 to the lowermost position 44 the first space 40 is subjected to a known volume reduction, in which said volume reduction is determined by the size of the transverse surface of the hollow cylinder 23 and the length of the stroke of the piston 15 between the centre position 43 and the lowermost position 44. During the known volume reduction an electronic pressure gauge 30 registers a pressure increase. Via gas laws that are known per se, said pressure increase is a measure for the size of the second free space 41 . In case of a known tillable volume of the bread pan 5 the combined volume of the dough portions 6 can be determined in this way. In case of a known constant homogeneous density of the dough of the dough portions 6 the combined mass of the dough portions 6 can also be determined based on the volume of the dough portions 6. The fact that the dough portions 6 may lie over each other does not affect the result of the measurement.
During measuring the volume of the dough portions as described above for figures 2A-2C, the connecting rod 28 of the drive cylinder 27 makes only one downward motion as a result of which the stamp 25 is placed on the bread pan 5 and the first volume 40 is reduced.
After measuring the pressure increase the pneumatic drive cylinder 27 can be actuated in reverse direction, as a result of which the bread pan 5 is released from the stamp 15. Subsequently after placing a next bread pan 5 a new measurement can be carried out.
By comparing the measured pressure increase within a certain margin with a desired pressure increase, it can easily be determined whether there is too much or too little dough in the bread pan 5. In this way a dough filled bread pan 5 can be approved of or rejected prior to further treatment. In this way it is for instance prevented that dough rises out of the bread pan or that too small loaves of bread are baked.