CIGARETTE MACHINE COMPRISING A SUCTION BELT CONVEYOR

Abstract

A cigarette machine comprises a suction belt conveyor including a rod guide channel, wherein the rod guide channel is delimited on one side by a material-conveying suction belt. Two channel cheeks are positioned opposite one another and configured to adjoin the rod guide channel An electromagnetic measuring apparatus comprises a resonator. The resonator comprises a first resonator half positioned on the side of the rod guide channel with the conveying suction belt, and a second resonator half of which is provided on the side which is situated opposite the first resonator half. The first resonator half is connected to the suction belt conveyor.

Claims

1-18. (canceled)

19. A cigarette machine comprising: a suction belt conveyor including a rod guide channel, wherein the rod guide channel is delimited on one side by a material-conveying suction belt; two channel cheeks positioned opposite one another and configured to adjoin the rod guide channel; and an electromagnetic measuring apparatus comprising a resonator, wherein the resonator comprises, a first resonator half positioned on the side of the rod guide channel with the suction belt conveyor, and a second resonator half of which is provided on the side which is situated opposite the first resonator half, wherein the first resonator half is connected to the suction belt conveyor.

20. The cigarette machine according to claim 19, wherein the electromagnetic measuring apparatus is a microwave resonator comprising a resonator cavity defined by the first resonator half and the second resonator half.

21. The cigarette machine according to claim 19, wherein the first resonator half is positioned adjacent to the suction belt conveyor.

22. The cigarette machine according to claim 19, wherein the second resonator half is positioned adjacent to the rod guide channel.

23. The cigarette machine according to claim 19, further comprising: a rod formation zone; and one or more trimming discs, wherein the electromagnetic measuring apparatus is positioned between the one or more trimming discs and the rod formation zone.

24. The cigarette machine according claim 19, wherein the electromagnetic measuring apparatus comprises a heating apparatus configured to heat at least one of the first resonator half and the second resonator half.

25. The cigarette machine according to claim 19, further comprising a compressed air apparatus configured to clean the first resonator half and the second resonator half.

26. The cigarette machine according to claim 19, wherein the electromagnetic measuring apparatus is configured to measure at least one of: (1) a mass; (2) a density; and (3) a moisture content of material conveyed on the suction belt conveyor.

27. The cigarette machine according to claim 26, wherein measurement results from the electromagnetic measuring apparatus are used to measure a tobacco mass in relation to a reference length.

28. The cigarette machine according to claim 27, wherein the tobacco mass is regulated using the measurement results.

29. The cigarette machine according to claim 27, wherein a taring measurement is configured to be carried out on an empty suction belt conveyor.

30. The cigarette machine according to claim 29, wherein a closing of the rod guide channel is configured to initiate the taring measurement.

31. The cigarette machine according to claim 29, wherein the taring measurement is performed in at least one position of the suction belt conveyor and is compared with one or more previously measured values, wherein the taring measurement is discarded if a deviation by more than a predetermined minimum amount occurs.

32. The cigarette machine according to claim 29, wherein the taring measurement is carried out in at least two positions on the suction belt conveyor and the measured values are compared with one or more previous measured values, and wherein a measured value with a smallest deviation from the pervious measured values is adopted as the measured value.

33. The cigarette machine according to claim 19, further comprising an evaluation apparatus configured to detect a joint of the suction belt conveyor using a peak detection in measurement signals.

34. The cigarette machine according to claim 33, wherein a mass value of the joint is determined during an empty measurement and is used to correct a measured mass signal at the joint.

35. The cigarette machine according to claim 33, wherein the evaluation apparatus is configured to detect the joint when measuring an empty suction belt conveyor by one of: (1) a rise in a measurement signal that is indicative of a mass; and (2) a lack of a rise in a measurement signal that is indicative of moisture.

36. The cigarette machine according to claim 33, wherein the evaluation apparatus is configured to detect the joint when measuring a filled suction belt conveyor by one of: (1) a rise in a measurement signal that is indicative of a mass; and (2) a decline in a measurement signal that is indicative of moisture.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] A preferred embodiment of the invention with the arrangement of the two resonator halves is described in greater detail below. The following is shown:

[0023] FIG. 1a illustrates a perspective view of an embodiment of a suction belt conveyor comprising a suction belt and a measuring apparatus;

[0024] FIG. 1b illustrates a close-up perspective view of a portion of the embodiment of FIG. 1a;

[0025] FIG. 2a schematically illustrates an embodiment of the resonator halves on the conveyor channel in a closed position

[0026] FIG. 2b schematically illustrates an embodiment of the resonator halves of FIG. 2b in an opened position; and

[0027] FIG. 3 illustrates the curve of the measurement signals of an empty belt with a joint.

DETAILED DESCRIPTION OF THE INVENTION

[0028] FIG. 1 shows a suction belt conveyor 1 comprising a suction belt 2 that extends in the conveying direction. The tobacco that is to be processed is conveyed into a zone 4 for rod formation by means of the suction belt 2. Paper 3 is supplied to the zone 4. The trimming discs 5 are arranged near the rod formation zone. The detailed view in FIG. 1b from the head end of the suction belt conveyor shows the suction belt conveyor 1 with its suction belt 2 and the trimming discs 5. In this instance, a sensor position 6 is arranged near the end of the suction belt conveyor, for example. The trimming discs in a cigarette machine are the apparatuses for controlling the tobacco mass that is inserted. They are arranged in pairs and positioned on both sides of the endless tobacco rod. They trim the transported tobacco at a particular height, wherein the mass is controlled either by varying the vertical position of the discs or by modifying the height of the belt relative to the trimming discs. Preferably, two trimmer discs that are disposed opposite each other are arranged on each channel.

[0029] The sensor system 6 represented here is a microwave cavity resonator consisting of two resonator halves. Of these two resonator halves, the first resonator half is arranged above the suction belt, while the second resonator half is arranged below the suction belt and preferably also below the lateral channel cheeks.

[0030] Measuring the density of the tobacco on the suction belt places high demands on the homogeneity of the measuring field. For a precise measurement of the density, the measuring field in the area of the tobacco must be as homogeneous as possible. A high degree of field homogeneity is achieved in the area of the measured material by using a microwave resonator comprising two resonator halves, with the suction belt positioned flat between them, thereby permitting accurate measurement results to be obtained.

[0031] The suction belt transporting the tobacco is a wear part that must be replaced regularly, for example once per shift. For this purpose, the entire suction belt conveyor is mechanically moved upward to permit the suction belt to be replaced. Once the suction belt has been replaced, the suction belt conveyor is returned to its starting position with a high degree of mechanical precision. The suction belt has a uniform distribution of material throughout, which makes a constant contribution to the measurement signals during a density measurement. This constant contribution is eliminated by the taring empty measurement. Only at a joint is the suction belt not homogeneous, and this can cause a disturbance in the measurement signals.

[0032] The sensor 6 comprises a microwave cavity resonator consisting of two half-shells. One half-shell is positioned directly below the lower opening of the rod guide channel and is fastened in the cigarette machine. The second half-shell is positioned with the suction belt conveyor directly above the suction belt and is moved together with the suction belt conveyor when the belt is replaced. The resonator does not function while the suction belt conveyor is moving. As a cavity resonator, the resonator is constructed as small as possible in order to concentrate the measurement field in the transport channel and to interfere as little as possible with the functioning of the suction belt.

[0033] FIG. 2a shows the closed arrangement with a lower resonator half 8 and an upper resonator half 7. The upper resonator half 7 in this instance is the first resonator half, which is arranged on the side of the rod guide channel with the conveying suction belt. The second resonator half 8 is arranged on the opposite, open side of the rod guide channel. The rod guide channel is delimited on the sides by the channel cheeks 9. The upper and second resonator halves 7 and 8 are shown with a semicircular housing shape in FIGS. 2a-b, wherein the measuring range between them extends over the entire area between the channel cheeks 9 and thus also includes the suction belt 2. FIG. 2b shows the open position, in which the suction belt conveyor is raised together with the first resonator half 7 in order to replace the suction belt 2, for example. A greater distance is created between the first resonator half 7 and the second resonator half 8 in this way, and so a measuring operation is not possible in the open position. In order to precisely remount the upper or the second resonator half 7, 8, fitting means can be provided on the channel cheeks, against which the two resonator halves are tensioned against each other into their exact positions, for example with force, thereby ensuring precise relative positioning.

[0034] The coupling and decoupling of the microwave signals preferably occurs on the second resonator half 8, which is securely attached to the cigarette machine. The channel cheeks 9 are made of plastic or ceramic, at least in the area of the sensor, and exert a constant influence on the measuring field of the resonator, which can be eliminated by a taring measurement of the empty resonance values.

[0035] As is also illustrated with reference to FIG. 1b, the trimming discs 5 are located near the zone 4 in which the rod forming is carried out. Rod forming occurs outside of the suction belt conveyor, wherein the trimming disks separate excess tobacco from the suction belt. A well-suited location for the placement of the sensor system is between the trimming discs 5 and the rod formation zone 4.

[0036] The resonator can be encapsulated and heated in order to minimize the influence of temperature fluctuations on the measurement at the location of the measuring apparatus. The heating of the resonator is controlled during operation such that the resonator always has a constant temperature. In the arrangement according to the invention, the risk arises that tobacco will accumulate on the lower half shell during production. It can also be removed during operation by means of compressed air.

[0037] FIG. 3 shows the curve of the measurement signals of an empty suction belt with a joint. The measured values A [MHz] and Phi are plotted. The measured value A refers here to the resonance value shift as it occurs compared to a measurement of the empty resonator. This resonance frequency shift depends upon the mass of the materials located in the measurement area between the resonator halves. Phi denotes a mass-independent moisture value, which can be determined, for example, from the quotient of the resonance frequency shift and the resonance broadening. FIG. 3 shows that a peak in the A value occurs at the joint of the suction belt, while the phi value remains substantially unchanged. This behavior of the measurement signals can be used to detect the joint in the suction belt during the taring measurement. A position determination can be carried out in this way so that, if an uneven distribution of tobacco subsequently occurs, for example, the influence of the joint can be taken into account using its position. In the manufacture of ‘heat-not-burn’ products, the endless tobacco rod is usually filled homogeneously, and so a position determination can be omitted, and the increase in density caused by the joint can be immediately recognized in the A values. At the same time, a minimum for the microwave moisture value phi arises because a different mass ratio occurs in the joint between the suction tape and the tobacco, in which the relative mass of the suction belt to tobacco is greater than in the other positions of the suction belt. The increase in mass in the region of the joint can be measured on the empty belt, and the measured tobacco masses at this location on the belt are corrected during production operation. Position tracking by means of the shaft encoder signal of the cigarette machine can also be utilized to correct the signal of the joint.