METHOD FOR CONTROLLING AN INFLATABLE SEALING SLEEVE IN A FILLING DEVICE AND FILLING DEVICE FOR FILLING FLEXIBLE CONTAINERS

Description

[0001] The invention relates to a method for controlling an inflatable sealing sleeve in a filling device for flexible containers and to such a filling device.

[0002] For filling flexible containers, such as valve bags, filling devices are used that have a filling nozzle onto which the valve bag is pushed for filling. To seal the filling nozzle against the container, such as a valve bag, it is known that the filling nozzle has an inflatable sealing sleeve on its outer circumference. After the container is pushed onto the nozzle, the sealing sleeve is inflated with compressed air to seal the gap between the filling nozzle and the bag. These sealing sleeves are wear parts, so their properties change over time. Furthermore, the quality and dimensions of the valve bags can vary, for example, from batch to batch. For this reason, it is difficult to consistently ensure a sufficient seal using the sealing sleeve and to prevent the valve bags from tearing due to excessive pressure in the sealing sleeve.

[0003] Document US 3 072 208 discloses a method for controlling at least one air-inflatable sealing sleeve in a filling device for flexible containers, in which the sealing sleeve is arranged on a filling nozzle and is designed to seal the filling nozzle against a container placed on it, and a filling device for filling flexible containers, which has a filling nozzle with at least one inflatable sealing sleeve onto which a section of a flexible container to be filled can be slid, and a compressed air supply device connected to the at least one sealing sleeve.

[0004] Against this background, the object of the invention is to improve the reliable sealing effect of a sealing sleeve between a filling nozzle and a flexible container in a filling device for flexible containers.

[0005] This problem is solved by a method having the features specified in claim 1 and by a filling device having the features specified in claim 8. Preferred embodiments are described in the dependent claims, the following description, and the accompanying figures.

[0006] The method according to the invention enables improved control of the inflation of a sealing sleeve in a filling system for flexible containers, thereby enhancing the sealing effect and durability of the sealing sleeve. In the filling device for flexible containers, for example, for filling bags or valve bags, a filling nozzle is provided onto which the container to be filled can be placed or pushed. The filling nozzle has at least one inflatable sealing sleeve arranged around its circumference, which seals the gap between the filling nozzle and the inserted container. The method according to the invention serves to control the inflation of the sealing sleeve in such a way as to achieve a reliable seal. According to the invention, a calibration step is initially provided in which the sealing sleeve is filled with compressed air while no container is placed on the filling nozzle.In this state, the sealing sleeve does not press against the inner wall of a container during filling, but can preferably expand freely without any external force acting upon it. In the calibration step, the sealing sleeve is filled with compressed air until it reaches a predefined expansion, in particular a predefined outer diameter. When this predefined expansion is reached, the pressure in the sealing sleeve, i.e., the pressure of the supplied compressed air, is determined, and the determined pressure value is stored as the target pressure value. This means that the filling pressure of the sealing sleeve at a desired outer diameter or expansion of the sealing sleeve is recorded. In the subsequent filling operation, i.e., during production when containers are filled, the sealing sleeve is filled or inflated with compressed air with the container attached until the filling pressure, i.e.,The pressure of the supplied compressed air, or the internal pressure of the sealing sleeve, corresponds to the previously stored target pressure value. This process ensures that the sealing sleeve is always sufficiently inflated, while simultaneously preventing the internal pressure from becoming too high and thus avoiding the rupture of the attached containers. Furthermore, pressure-controlled inflation of the sealing sleeve compensates for potential wear of the sealing sleeve and variations in the quality and dimensions of the attached containers.

[0007] The described calibration step is preferably performed after replacing the sealing sleeve, i.e., after a new sealing sleeve has been mounted on the filling nozzle, for example, to replace a worn sealing sleeve. Alternatively or additionally, a calibration step can be performed at intervals, for example, at predetermined intervals. The intervals can be regular or irregular. For example, a calibration step can also be performed when a new batch of containers is used, in order to adjust the desired expansion of the sealing sleeve to the selected container. In particular, a calibration step can also be performed if it is determined that the sealing effect of the sealing sleeve is insufficient.

[0008] Furthermore, it is possible to perform a calibration step for several different predefined expansions in the sealing sleeve and to save several corresponding target pressure values, with each target pressure value being assigned to a specific expansion of the sealing sleeve. This makes it possible to save different settings, which are adapted, for example, to different containers to be filled, especially bags of varying dimensions. Depending on the selected container or bag, a corresponding previously saved target pressure value can then be accessed to inflate the sealing sleeve.

[0009] Preferably, a stored target pressure value is assigned to a type of container. The target pressure value is specifically adapted to the inner diameter of the section of the container to be placed on the filling nozzle, for example, the inner diameter of a valve section of a valve bag.

[0010] During the calibration step, the achievement of the predefined expansion of the sealing sleeve during inflation with compressed air can be manually recorded. For example, an operator can measure the expansion of the sealing sleeve or record it with a suitable gauge and then manually stop the inflation process and record the measured pressure value. However, it is also possible to detect the achievement of the predefined expansion of the sealing sleeve during inflation with compressed air using at least one sensor or expansion sensor. This allows for an automated design of the calibration process and greater calibration reliability.

[0011] In one possible embodiment of the invention, the achievement of a predefined expansion of the sealing sleeve during filling with compressed air can be detected by at least one optical sensor, one electrical sensor, and / or one touch sensor. In principle, however, any suitable sensor devices can be used that are capable of detecting the expansion, in particular the diameter of the outer circumference of a sealing sleeve, with sufficient accuracy. Electrical sensors, for example, can detect contact or touching of the sealing sleeve on the sensor via electrical contacts. This is particularly suitable if the sealing sleeve has electrically conductive properties. For example, two diametrically opposed electrodes could be brought into an electrically conductive connection by the sealing sleeve when the sealing sleeve touches the electrodes.However, mechanical sensors are also conceivable that react to contact with the sealing sleeve and, for example, actuate switching contacts. An optical sensor, such as a laser sensor, could be used to detect the distance to the outer wall of the sealing sleeve. Furthermore, a camera system could also detect the dimensions through suitable image analysis. In another possible configuration, the circumferential length of the sealing sleeve could be determined by a sensor rolling along its surface.

[0012] According to another possible embodiment, the predefined expansion of the sealing sleeve could also be determined by measuring the volume of compressed air supplied. For this purpose, the volume flow rate of the supplied compressed air could be determined, thus calculating the supplied volume. At a predetermined volume corresponding to a predetermined expansion, the pressure can then be measured and stored as the target pressure value.

[0013] In addition to the method described above, the invention relates to a filling device for filling flexible containers, preferably a filling device in which the method described above is used. It should be understood that the preferred embodiments of the filling device described below also represent preferred variants of the method described above, and that the described preferred method features are also to be regarded as preferred features of the filling device.

[0014] The filling device according to the invention is designed for filling flexible containers, for example, valve bags. The filling device has a filling nozzle with at least one inflatable sealing sleeve. The sealing sleeve is arranged on the filling nozzle such that it surrounds the outer circumferential wall of the filling nozzle in an annular manner. A section of the container to be filled, for example, a valve section of a valve bag, can be pushed onto the filling nozzle. The sealing sleeve serves to seal the gap between the filling nozzle and the inside of the pushed-on container. The filling device also has a compressed air supply device, which is connected to the sealing sleeve and by means of which the sealing sleeve can be inflated. The sealing sleeve is inflated after the container is pushed onto the nozzle in order to achieve its sealing effect.After filling the container, the compressed air is released from the sealing sleeve to reduce the diameter of the sealing sleeve and to allow the container to be removed from the filling nozzle.

[0015] According to the invention, at least one pressure sensor is arranged in the compressed air supply device, via which the pressure of the supplied compressed air and thus the internal pressure of the sealing sleeve can be determined. The pressure sensor is connected to a control unit, which is also connected to the compressed air supply device and controls it, i.e., in particular, initiates the filling or inflation of the sealing sleeve and the release of the air from the sealing sleeve. The control unit is designed such that it can perform a calibration step, or performs one in the sequence described below. The calibration step is carried out without a container being pushed onto the filling nozzle. In the calibration step, the sealing sleeve is inflated by actuating the compressed air supply device. Inflation continues until the sealing sleeve reaches a predetermined expansion, in particular a predetermined outer diameter.Once this expansion is reached, the compressed air supply can be stopped by appropriately controlling the compressed air supply device. The pressure is then measured by the pressure sensor, and the pressure value measured by the pressure sensor is stored as a target pressure value in the control unit. In a subsequent operating mode of the filling device, in which containers are filled, the sealing sleeve is inflated by controlling the compressed air source after each container is placed on the device until the pressure in the sealing sleeve, or the pressure in the compressed air supply to the sealing sleeve, reaches the stored target pressure value. Upon reaching the target pressure value, the compressed air supply device is controlled to stop the compressed air supply. After the container is filled, the compressed air supply device is controlled to release the compressed air from the sealing sleeve, allowing it to return to its original size.This process is repeated for each container to be filled, which is pushed onto the filling nozzle.

[0016] In the calibration step, the expansion of the sealing sleeve can be determined manually, as described above. Preferably, however, the filling device has an expansion sensor designed to detect the expansion of the sealing sleeve and connected to the control unit. The expansion sensor can then transmit either a measurement of the expansion or a signal indicating that a desired expansion level has been reached to the control unit, allowing the control unit to then initiate pressure measurement and storage of the target pressure value. The expansion sensor can be configured in any suitable way, for example, as described above.

[0017] The expansion sensor can be, for example, an optical sensor, a mechanical sensor, an electrical sensor, a touch sensor, and / or a sensor device for detecting the volume of compressed air supplied to the sealing sleeve. For exemplary designs of the expansion sensor, please refer to the description above.

[0018] In another possible embodiment of the filling device, the expansion sensor can be attached to a positioning device, which allows the expansion sensor to be positioned differently. The positioning device is preferably designed such that the at least one expansion sensor is positioned in a first position adjacent to the sealing sleeve and in a second position away from the sealing sleeve. The positioning device can be connected to the control device in such a way that the control device can initiate the desired positioning of the positioning device. Thus, the expansion sensor can be moved to the first position via the positioning device during the calibration step in order to detect the expansion of the sealing sleeve. During production, i.e.,During the filling of containers, the expansion sensor is preferably located in a position away from the filling nozzle so that it does not obstruct the placement of the containers. The control device can therefore be designed to move the expansion sensor to the second position by activating the positioning device when no calibration step is performed.

[0019] In a further possible embodiment of the invention, the compressed air supply device comprises at least one valve and / or one compressor that can be controlled by the control device. This enables the control device to switch the compressed air supply to the sealing sleeve on and off and also to cause the pressure to be released from the sealing sleeve by appropriately controlling at least one valve and / or the compressor.

[0020] In a particular embodiment of the invention, the filling device can be designed as a vacuum filling device, which has a vacuum chamber for receiving a container to be filled. That is, during filling, the container is located in a vacuum chamber, so that a negative pressure is exerted on the container from the outside, which assists or causes the filling of the container through the filling nozzle. Especially with such vacuum filling devices, it is important that the gap between the filling nozzle and the inserted container is sealed so that no product can escape through this gap into the vacuum chamber.

[0021] The control device of the filling device is preferably designed in such a way that it applies or executes the method as described above.

[0022] The invention is described below by way of example with reference to the accompanying figures. These show: Fig. 1 schematically shows a filling plant for valve bags, Fig. 2 schematically shows a top view of the filling supports of the filling plant according to Figure 1 , Fig. 3 schematically a side view of the filling nozzle according to Figure 2 , Fig. 4 schematically shows the filling plant according to Figure 1 during a calibration step, Fig. 5 schematically shows an expansion sensor according to a first embodiment, Fig. 6 schematically shows an expansion sensor according to a second embodiment, Fig. 7 schematically shows an expansion sensor according to a third embodiment, Fig. 8 schematically shows an expansion sensor according to a fourth embodiment, and Fig. 9 schematically shows an expansion sensor according to a fifth embodiment.

[0023] The bottling plant 2 as shown schematically in Figure 1The device shown has a filling nozzle 4 onto which a flexible container, such as a valve bag 6 with its valve section 8, can be slid, so that the filling nozzle 4 extends into the interior of the valve bag 6 and a material to be filled, in particular a powdered material, can be introduced into the valve bag 6 through the filling nozzle 4. The material can be filled into the valve bag 6 through the filling nozzle 4 by means of overpressure. Alternatively or additionally, the valve bag 6 can be surrounded by a vacuum chamber 10 in which a negative pressure is generated and acts on the valve bag 6 from the outside. To seal the filling nozzle 4 in its circumferential region against the inner wall of the valve section 8 of the valve bag 6, a sealing sleeve 12 is arranged on the filling nozzle 4, which can be filled and inflated with compressed air or a pressurized gas.The sealing sleeve 12 can thus be enlarged in its expansion to press itself against the inner wall of the valve section 8, creating a seal. To remove the valve bag 6 from the filling port 4, the pressure in the sealing sleeve 12 can be released, so that the sealing sleeve 12 expands in its size or diameter D (see figure). Figure 2 ) reduced in size.

[0024] As in Figure 4As shown schematically in more detail, the sealing sleeve 12 is connected to a compressed air supply device 14, through which the sealing sleeve 12 can be filled with compressed air and through which the compressed air can be released from the sealing sleeve 12. In this example, the compressed air supply device 14 has a compressed air source 16, which is connected to the sealing sleeve 12 via a compressed air line 18. The compressed air source 16 can include a compressor or be connected to a central compressed air supply. Furthermore, a control device 20 is provided, which controls the compressed air source 16 and is connected to it for this purpose. The control device 20 can, for example, control a compressor and / or at least one valve in the compressed air source 16, in particular to switch the supply of compressed air on and off.A sensor 22, configured as a pressure sensor 22, is arranged on the compressed air line 18 and is also connected to the control unit 20 for communication purposes, so that the measured values ​​output by the pressure sensor 22 are forwarded to the control unit 20. Furthermore, an expansion sensor 24 is provided, which detects the expansion of the sealing sleeve 12. The expansion is, in particular, the diameter D of the sealing sleeve 12. The expansion sensor 24 can be configured to continuously measure the expansion and transmit the measured value to the control unit 20. Alternatively, as described in more detail below, the expansion sensor 24 can be configured only to detect when a predetermined expansion, i.e., a predetermined diameter D, has been reached.

[0025] With the in Figure 4In the illustrated embodiment, the sealing sleeve 12 can be calibrated by first filling it with compressed air without the valve bag 6. For this purpose, the control unit 20, in a calibration step, activates the compressed air source 16 so that compressed air is directed into the sealing sleeve 12. For example, the control unit 20 opens a controlled valve or switches on a pump or compressor. During the filling process, the pressure sensor 22 detects the pressure in the compressed air line 18, which essentially corresponds to the internal pressure of the sealing sleeve 12. Simultaneously, the expansion sensor 24 detects the expansion or diameter D of the sealing sleeve 12.When the expansion reaches a predetermined value, which is stored in the control unit 20, the pressure measured by the pressure sensor 22 is detected, and the control unit 20 shuts off the compressed air supply to the sealing sleeve 12 by appropriately controlling the compressed air source 16. The detected pressure value is stored by the control unit 20 as the target pressure value. In the subsequent production mode, in which valve bags 6 are filled, the valve bags 6 are operated as described in [reference to relevant section]. Figure 1The sealing sleeve 12 is shown being pushed onto the filling port 4. Then, by activating the compressed air source 16, the control unit 20 fills the sealing sleeve 12 with compressed air until the pressure sensor 22 detects a pressure value corresponding to the previously stored target pressure value. The compressed air supply is then stopped by switching off the compressed air source 16, and the sealing sleeve 12 reaches a predetermined expansion at which it seals against the valve section 8 as desired. This means that the predefined expansion used for calibration is matched to the diameter of the valve section 8. Different target pressure values ​​can also be determined and stored for different expansions, so that a corresponding setting can later be selected on the control unit 20 according to a specific valve type.After the valve bag 6 is filled, the control device 20 switches the compressed air source 16 so that the pressure is released from the sealing sleeve 12 and its diameter D decreases.

[0026] The expansion or diameter D can, in principle, be determined or measured in any suitable way during the described calibration step, for example, manually. For this purpose, an operator can use a ruler or suitable gauge and manually input the achievement of the desired expansion into the control unit 20, for example, by activating a corresponding control element. Preferably, however, an expansion sensor 24 is provided that detects when the predefined expansion has been reached. Such an expansion sensor 24 can be designed in a variety of ways. Based on the Figures 5 to 9 Examples of the design of the expansion sensor 24 are described.

[0027] Figure 5 Figure 1 schematically shows an expansion sensor 24a, which is designed as an electrical sensor. The expansion sensor 24a has two diametrically opposed electrodes 26, which are spaced apart by a distance corresponding to the predetermined expansion or diameter D of the sealing sleeve 12. If the sealing sleeve 12 is made of an electrically conductive material, the electrodes 26 come into electrical contact with the sealing sleeve 12 at the moment the sleeve makes contact with the electrodes 26, thus allowing the attainment of the predefined expansion to be determined.

[0028] Figure 6Figure 24b shows an example of a mechanical expansion sensor. This sensor has two stop elements 28, which are diametrically spaced apart by a distance corresponding to the predefined expansion or predetermined diameter D. The stop elements 28 can be equipped with sensors, such as force transducers or contacts, which detect a deflection caused by contact with the sealing sleeve 12. The predetermined expansion can also be achieved in this way.

[0029] Figure 7Figure 24c shows a variant in which the predetermined expansion of the sealing sleeve 12 is detected using a pressure sensor. The expansion sensor 24c has a special plug 30 with a recess that has an inner diameter corresponding to the predetermined expansion of the sealing sleeve 12. This plug 30 is pushed over the sealing sleeve 12, and the sealing sleeve is filled with compressed air. If compressed air is simultaneously supplied through the filling port 4, it flows out as long as the sealing sleeve 12 does not come into contact with the inner circumference of the plug 30. When the sealing sleeve 12 enters a sealing contact with the inner circumference of the plug 30, no more compressed air escapes through the filling port 4, which can be detected by a pressure increase in the filling port 4.

[0030] A fourth way to determine the extent or diameter of the sealing sleeve 12 is based on Figure 8As explained below, in this embodiment, the expansion sensor 24d is designed to detect the length of the outer circumference of the sealing sleeve 12. For this purpose, the expansion sensor 24d has a roller 32 which can roll along the outer circumference of the sealing sleeve 12. By counting the revolutions of the roller 32, the length of the outer circumference of the sealing sleeve 12, and thus its expansion or diameter D, can be determined.

[0031] In another variant, an optical expansion sensor 24e could be used, as shown schematically in Figure 9The optical expansion sensor 24e can be a camera in whose camera image the expansion of the sealing sleeve 12 is determined by image analysis. Alternatively, the expansion sensor 24e can be designed as a laser sensor, which uses laser beams to determine, for example, the distance between the outer diameter of the sealing sleeve 12 and the expansion sensor 24e. The resulting expansion or diameter D can then be determined.

[0032] In another possible measuring principle, the expansion of the sealing sleeve 12 can be determined via the supplied volume of compressed air. For this purpose, the compressed air source 16 can have a volume flow sensor, or a suitable volume flow sensor can be arranged in the compressed air line 18, for example also in combination with the pressure sensor 22.

[0033] It is understood that numerous other measuring systems can be used to determine the achieved expansion or diameter D of the sealing sleeve 12 and / or to detect the achievement of a predetermined expansion and transmit it to the control device 20. Reference symbol list

[0034] 2 Filling system 4 Filling nozzle 6 Valve bag 8 Valve section 10 Vacuum chamber 12 Sealing sleeve 14 Compressed air supply device 16 Compressed air source 18 Compressed air line 20 Control device 22 Pressure sensor 24, 24a - 24e Sensor, expansion sensor 26 Electrodes 28 Stop element 30 Plug 32 Roller

Claims

1. A method for controlling at least one sealing collar (12) inflatable by means of compressed air in a filling device (2) for flexible containers (6), in which the sealing collar (12) is arranged on a filling spout (4) and designed to seal the filling spout (4) relative to an attached container (6), characterized in that, in a calibration step, the sealing collar (12) is filled with compressed air without an attached container until the sealing collar (12) reaches a predefined expansion, wherein, at the predefined expansion, the pressure of the supplied compressed air is determined and the determined pressure value is stored as a target pressure value, and that, when subsequently filling a container (6), the sealing collar (12) is filled with compressed air with the container attached until the pressure of the supplied compressed air has reached the stored target pressure value.

2. The method according to claim 1, characterized in that the calibration step takes place after the sealing collar (12) has been replaced and / or in intervals, preferably predetermined intervals.

3. The method according to claim 1 or 2, characterized in that a respective calibration step takes place for several different predefined expansions of the sealing collar (12), and several accompanying target pressure values are correspondingly stored.

4. The method according to one of the preceding claims, characterized in that a stored target pressure value is allocated to a type of container (6).

5. The method according to one of the preceding claims, characterized in that at least one sensor (24) detects when the predefined expansion of the sealing collar (12) has been reached while being filled with compressed air.

6. The method according to one of the preceding claims, characterized in that at least one optical sensor (24e), an electric sensor (24a) and / or a touch sensor (24b) detects when the predefined expansion of the sealing collar (12) has been reached while being filled with compressed air.

7. The method according to one of the preceding claims, characterized in that the predefined expansion of the sealing collar (12) is determined by measuring the supplied volume of compressed air.

8. A filling device or filling flexible containers, which has a filling spout (4) with at least one inflatable sealing collar (12), onto which a section (8) of a flexible container (6) to be filled can be slipped, and a compressed air supply device (14) connected with the at least one sealing collar (12), characterized by at least one pressure sensor (22) arranged in the compressed air supply device (14), as well as a control device (20) that is connected with the pressure sensor (22) and the compressed air supply device (14), and configured in such a way that, in a calibration step, it inflates the sealing collar (12) without an attached container (6) by actuating the compressed air supply device (14), until the latter has reached a predetermined expansion, and once the predetermined expansion has been reached, acquires a pressure value output by the pressure sensor (22) and stores the latter as a target pressure value, and subsequently, once a container (6) to be filled has been slipped onto the filling spout (4), inflates the at least one sealing collar (12) by actuating the compressed air supply device (14) until the stored target pressure value has been reached.

9. The filling device according to claim 8, characterized by at least one expansion sensor (24, 24a-24e), which is designed to acquire the expansion of the sealing collar (12) and connected with the control device (20).

10. The filling device according to claim 9, characterized in that the at least one expansion sensor (24, 24a-24e) is an optical sensor (24e), an electric sensor (24a), a touch sensor (24b) and / or a sensor device for acquiring the compressed air volume supplied to the sealing collar (12).

11. The filling device according to claim 9 or 10, characterized in that the at least one expansion sensor (24, 24a-24e) is fastened to a positioning device, which is configured in such a way that the at least one expansion sensor (24, 24a-24e) can be positioned in a first position adjacent to the sealing collar (12) and in a second position distant from the sealing collar (12).

12. The filling device according to one of claims 8 to 11, characterized in that the compressed air supply device (14) has at least one valve that can be actuated by the control device (20) and / or a compressor that can be actuated by the control device (20).

13. The filling device according to one of claims 8 to 12, characterized in that the filling device is designed as a vacuum filling device with a vacuum chamber (10) for accommodating a container (6) to be filled.

14. The filling device according to one of claims 8 to 13, characterized in that the control device (20) is configured in such a way as to implement the method according to one of claims 1 to 7.