HK1021302A - Device for detecting the tobacco-temperature in the process of manufacturing the cigarette - Google Patents

Description

Device for detecting tobacco temperature during cigarette production

The invention relates to a device for detecting measured values corresponding to the tobacco temperature as a correction value for a temperature-dependent control function associated with the cigarette production process.

In the tobacco processing industry, measuring devices of the type described above are often used in combination with program control in order to compensate for the effects of temperature differences or drastic temperature changes in the tobacco on the regulating function or its control means.

An example of such a method is disclosed in applicant's US-PS 5063943.

The aim of the invention is to obtain a reliable temperature value that represents the temperature of the entire cross-section of the tobacco rod to be corrected for the regulating function.

The above object is achieved according to the invention in that: the device is constructed and arranged to indirectly sense the temperature of the tobacco. An additional feature of the invention provides that the measuring sensor detects the temperature of a medium which interacts with the tobacco flowing through the production process by temperature exchange.

By means of such a measuring device, the measuring accuracy can be ensured, since it avoids the difference between the internal and surface temperature of the tobacco rod, which is caused by direct measurement of the tobacco rod. For example, machine parts can be used as a substitute medium for determining the tobacco temperature, in particular after a longer period of operation, which parts have a determined operating temperature or tobacco temperature. According to a preferred embodiment, a particularly reliable and simple temperature measurement in terms of measurement technology is achieved in the following manner: the measuring sensor is configured to measure the temperature of process air involved in the formation of the tobacco rod in a dispenser of the tobacco rod forming machine. With such a measuring device with a measuring sensor, precise measurement results can be obtained with the simplest structure, for example in the form of a platinum wire resistor.

According to a preferred embodiment, another advantage of the above-mentioned measuring device is achieved: the above-mentioned measuring sensor is mounted at the end of the suction belt where the tobacco rod is prepared and located on the cigarette making machine, wherein it is further proposed to mount the measuring sensor in the area immediately behind the passing suction belt in the flow path of the aspirating air. In the region of the tobacco rod conveyor, the tobacco heats the air which is drawn through the suction belt in the following manner: the measured air temperature optimally corresponds to the tobacco temperature.

The measurement signal obtained in this way, which corresponds to the tobacco temperature, can be used, for example, as a correction signal for correcting the measured hardness during hardness adjustment or as a correction signal for temperature compensation during moisture measurement. In one embodiment, a preferred use of the measurement signal is to connect the measurement sensor to a switching device of a rod microwave weight regulator.

By means of the measuring device described above, not only the strongly varying temperature of the surface of the tobacco rod, which is directly influenced by the environment, can be measured, but also the actual tobacco temperature is measured in the vicinity of the measuring and receiving element by contacting the air flowing through the entire cross-section of the tobacco rod, in order to correct the regulating measured value.

Indirect tobacco temperature measurement makes possible economic investment, in particular, a simplified measuring device in the gas stream.

The invention will be further described with reference to the following examples which are illustrated in the accompanying drawings.

The figure shows a schematic representation of the temperature measurement in the region of a tobacco rod smoking and conveying band of a cigarette maker dispenser in combination with a microwave weight regulating device.

In the drawing SZ, the rod forming zone is indicated, in which the tobacco is conveyed from a distributor of a known tobacco rod machine (as described in US-PS 4373538), and in which the tobacco passes through a shaft 1 to an air-permeable tobacco rod conveyor suction belt 2, which is guided by an orifice plate 3, behind which orifice plate 3 a negative pressure chamber 4 is arranged. The negative pressure is maintained by a schematically depicted line 6 leading from a negative pressure source, such as a fan 7. The cut tobacco is formed into a tobacco rod S in a forward movement by the suction air flowing through the air-permeable suction belt 2 and is discharged in the direction of the arrow 8. To drive the suction belt 2 around the rollers 9 and 11, one of the rollers is driven. A known (e.g., US-PS3030966), and thus only schematically illustrated, ecreteur 12 removes excess tobacco, the ecreteur 12 preferably comprising a rotating tangential, tobacco-retaining tab or impeller to remove excess tobacco projecting from the trimming plane (cut-off plane E). The tobacco rod S is thus flattened and subsequently compacted in a cigarette device into the shape 13 schematically shown in the drawing and then rolled up with a cigarette paper strip 14, thus producing a rod which is further divided into individual cigarettes. The removed excess tobacco T is returned to the dispenser via a hopper 16.

The cutting plane E of the trimming member 12 is controlled by a servo motor controlled by the adjuster 18 to move the trimming member 12 in a direction toward and away from the suction belt 2. The controller 18 receives a density (flow) setpoint signal from a setpoint transmitter 19, while a density measurement transmitter 21 provides an actual value signal. A density measuring device suitable for this purpose is, for example, the switching device 22 disclosed in DE-OS19705260, which is used for microwave weight regulation of tobacco rods and which, after the tobacco shaping 13, receives a density-related signal on the wrapped tobacco rod.

The switching device 22 constitutes a high-frequency resonator, which is provided with a resonator 23 inside a housing 24 shown in cross-section in the figure. Coaxial cables 28 and 29 are used for the input coupling of the microwave signal of the generator 26 and for the output coupling of the signal to an evaluation device 27. The resonator 23 made of a dielectric material is made in a cylindrical shape and fixed in a housing 24 in a manner not shown.

Said housing 24 extends between its inlet and outlet with a tubular guide 31 of electrically non-conductive material, by which said tobacco rod S wrapped by the band 14 of cigarettes is guided along the arrow 8 to detect its dry and/or wet quality and/or total mass or dielectric constant. The microwave signal from the generator 26 is transmitted to the switching device 22 via a circulator 32 which prevents feedback. The output signal of the switching device 22 is transmitted via the coaxial cable 29 and a circulator 33 to a microwave diode 34, which converts the microwave signal into a voltage-equalizing signal. The output signal then passes from the diode 34 via an a/D converter 36 to the evaluation device 27, which converter 36 digitizes the output signal of the diode 34. In addition, the converter also acts as a gate since it allows the signal to pass only when it gets a release pulse from the frequency controller 37 via the conductor 38.

Since the signal of the microwave diode 34 is dependent on the temperature of the tobacco, a compensation is determined for this purpose, wherein the temperature of the tobacco is detected indirectly, i.e. the temperature of the above-mentioned suction air which comes into contact with the tobacco rod S and flows through it, according to the invention. For this purpose, a measuring sensor 39, for example a commercially available platinum resistor or thermistor, is installed in the vacuum chamber 4 in a given region of the suction belt 2 and is connected to the evaluation device 27 via a signal line 41. The corrected or compensated output signal of the above-mentioned evaluation device 27 is passed on to the density measured value transmitter 21 via a signal line 42.

Claims (6)

1. Device for detecting a measured value corresponding to the tobacco temperature as a correction value for a temperature-dependent control function associated with the cigarette production, characterized in that: the device is constructed and arranged to indirectly sense tobacco temperature.

2. The apparatus of claim 1, wherein: the measuring sensor (39) detects the temperature of a medium which interacts with the tobacco conveyed in the production process by means of temperature exchange.

3. The apparatus of claim 1 or 2, wherein: the measurement sensor (39) is configured to measure the temperature of air involved in the rod forming process in the dispenser of the rod forming machine.

4. The apparatus of one of claims 1 to 3, wherein: the measuring sensor (39) is mounted at the end of the suction belt (2) where the tobacco rod (S) is prepared and located on the cigarette making machine (13).

5. The apparatus of one of claims 1 to 4, wherein: the measuring sensor (39) is mounted in the area of the flow path of the suction air which lies against the rear side of the passing suction belt (2).

6. The apparatus of one of claims 1 to 5, wherein: the measuring sensor (39) is connected to a switching device (22) for microwave weight control of the tobacco rod (S).