EP2098452B1 - Method and device for filling a container - Google Patents

Description

The present invention relates to a method and a device for filling a flexible container, in particular a bag, with pourable materials and in particular with bulk materials, wherein the flexible container is filled by means of a filling member. The invention is used for filling of powdery products or granules and in particular for filling light and very fine powder products, such as aerosils, as well as used for color production carbon black particles or TiO ₂ particles or TiO ₂ containing materials or the like, in which the bulk material during filling contains a considerable amount of air. However, the invention is also suitable for filling other pourable or flowable materials or for filling toxic or environmentally hazardous products.

Various systems for filling bulk materials have become known in the prior art. In conventional systems for filling pourable goods into valve bags, the bulk goods contain a certain proportion of air during filling. The air content contained in the bag is released slowly via corresponding openings in the bag wall to the outside.

Nevertheless, there is an overpressure in the bag during the filling process, which is for example about 150 to 250 millibars. This pressure is still in the moment of switching off the Promoter. Now, if at the moment of shutdown of the conveying member, the bag is withdrawn from the filling member, the pressure prevailing inside the bag abruptly discharges over the still open valve, so that a certain and especially for light materials significant amount of product from the bag into the open is transported. This leads to a weight loss of the bag and also to contamination of the system and the bags. During the filling of, for example, soot particles or TiO ₂ particles, even small amounts of escaping product lead to a very considerable pollution of the environment.

In order to reduce the product leakage and to increase the cleanliness of the equipment and the sacks, it is therefore in the prior art before waiting for the bag to wait until the pressure inside the bag has degraded over the wall, or the pressure must be via a bypass be dissipated. The pressure reduction over the wall requires a considerable amount of time, in particular for light bulk goods, so that a drastic reduction of the filling performance must be expected. If the pressure is removed via a bypass, the pressure reduction is accelerated, but does not prevent the product from being discharged through the bypass, which then leads to a weight loss of the bags. This also results in significant weight fluctuations. In addition, the escaping product usually has to be discarded. Overall, this condition means an increase in operating costs.

In the prior art is with the US 3,533,454 a device has become known, are filled with the materials in bags. During the filling process, the lateral surfaces of the bag are first pressed in. During the filling process, the side walls are then expanded so that the pored sidewalls of the bag do not become clogged during the filling process by the filling material. Through the open pores should During the filling process a continuous venting done. Due to the constant ventilation, the filling rate during filling can be increased. This known technique only leads to a relatively small shortening of the entire filling process, because this is considerably determined by the maximum pressure in the bag at the end of the filling process and the resulting waiting time after the end of the filling process. Since the maximum pressure is unchanged, the time for the pressure reduction and thus the waiting time remain unchanged.

In the prior art is further with the DE 195 41 975 A1 a method and an apparatus for forming and venting open bags after the filling process has become known in which the upper edges of the projections of the bag wall are clamped in a slidable manner with clamping jaws and in which, after filling, the clamping jaws are rolled in the direction of the filling material level present in the bag; to remove the contained air from the sack via a lance inserted through the upper opening of the sack and subject to vacuum. This can effectively shorten the waiting time. A disadvantage of the known device is that not only air, but also filling material is discharged through the introduced into the bag lance.

From the DE 37 03 714 A1 a bagging machine for filling powdery goods has become known with a filler neck, in which at the filler neck provided with a filter and connected to a vacuum source air outlet opening is provided which serves to extract the air contained in the bag. With such a device powdery bulk materials can be filled into valve bags. A disadvantage of the known device, however, is that when using a coarse-pore filter material still a significant proportion of contents is discharged through the outlet, while using a fine-pored filter material, the pores quickly through the contents, so that the effect is significantly reduced.

In such devices known from the prior art, wherever the air product is able to escape, the sack must therefore be overfilled with the expected weight loss in order to reduce or compensate for the weight deviations of the filled sack. But since this weight loss varies, a greater spread of the weights is inevitable, which must be filled to maintain a minimum weight usually more material in the bags, as would actually be necessary. Alternatively, the settling time can be extended after the end of the filling process to reduce the overpressure.

In all cases described a procedural disadvantage, which is a noticeable cost increase by a significant reduction in performance and / or by material loss and possibly dirty bags.

Furthermore, in the unpublished international patent application PCT / EP2007 / 010252 describes an apparatus and a method for filling bags with pourable goods, wherein a container to be filled via a filling member is filled by means of a filling process. The filling process has a filling section, a calming section and a picking section. During the filling section, a pourable material is filled into the container, in the calming section, a calming phase is provided for depressurization and in the removal section, the container is removed from the filling member. The filling process is thereby shortened by reducing the volume available to the container during a substantial part of the filling process in order to keep the pressure prevailing in the container high, while at the end of the filling process, the available volume Volume of the container is increased in order to reduce the pressure prevailing in the container quickly. In this method, the pressure is held up during the filling of the bulk goods in the bag. When the target total weight is reached, the filling section is terminated, and thereafter, in the settling section, the available volume is increased to accelerate the filling process as a whole.

Compared to the prior art, it is the object of the present invention to provide a method and an apparatus available, with or with which a rapid filling of flexible containers is possible, with the decrease only a small or even virtually no weight loss occurs.

This object is achieved by a method having the features of claim 1. The device according to the invention is the subject of claim 11. Preferred developments of the invention are the subject of the dependent claims. Further advantages and features emerge from the exemplary embodiment.

The inventive method is provided for filling formed as a valve bag flexible containers with pourable goods and is preferably used for filling valve bags with in particular light pourable goods. The valve bag to be filled is filled with a filling member or with several filling members by means of a filling process. The filling process comprises at least one filling section, a calming section and a removal section. During the filling section, at least one pourable material is filled into the valve bag, and at least one calming phase for venting is provided in the calming section. In the removal section of the valve bag is removed from the filling member. During at least part of the filling section, a venting pressure is exerted on the valve bag from the outside with at least one pressing device in order to reduce the volume available to the valve bag. Furthermore, at least in the calming phase with the at least one pressing device exerted a pressing pressure on the container to vent the valve bag and reduce the volume available to the valve bag. The pressing pressure is exerted until a predetermined reduction of the volume available to the valve bag is achieved, whereupon the pressing pressure of the pressing device is reduced to the valve bag and the valve bag is removed from the filling element.

Preferably, at the end of the filling process before the decrease in the volume of the container and in particular the volume available to the container is increased in order to reduce the pressure prevailing in the container.

For the purposes of this application, the term "filling process" is understood to mean the process from putting on or arranging the container until the removal or removal of the filled container. The filling process comprises in particular the placement or attachment of the container, the actual filling of the container and the removal of the filled container.

The term "filling process" is understood to mean the process of filling, that is to say the filling section, in which at least one phase with coarse flow filling and at least one phase with fine flow filling can be provided. For the purposes of this application, the term "during the filling process" is understood to mean that the corresponding process takes place in terms of time after the start of the filling process, ie after arranging or plugging on and before the container is taken off.

A significant advantage of the invention is the reduction of the volume in the settling phase until a predetermined reduction of the volume available to the container is achieved. This ensures that the internal pressure is sufficiently reduced, so that a decrease without material leakage is possible. The predetermined reduction is preferably based on empirical values for individual ones to be filled Products set. The calming phase follows the filling process. During the calming phase, usually no filling material is filled into the container.

By increasing the volume available to the container before the decrease, the pressure prevailing in the container is reduced directly in proportion to the increase in volume, so that the volume increase directly achieves a pressure reduction, since the flexible container will immediately take up the increased volume due to the increased internal pressure. Consequently, the take-off pressure can be quickly reached, so that the decrease of the container no high loss of material arises because the pressure inside the container is reduced by the increase in volume.

Another advantage of the method according to the invention is better bag venting during the settling phase.

Preferably, a pourable material is filled during the filling section with the addition of air in the container. Optionally, a welding of the bag can be done after the filling process.

The filling process can also be further shortened by reducing the available volume of the container during a substantial part of the filling process, in order to keep the pressure prevailing in the container high during filling. In the calming phase, a further increased pressure is then exerted until finally at the end of the filling process the pressing pressure is reduced and thus the available volume of the container is increased in order to rapidly reduce the pressure prevailing in the container.

Basically, a bag starts to vent when there is overpressure, ie when there is a pressure difference to the environment. This time typically occurs from about 50% of the weight to be filled. Due to the fact that in this development of the method only a reduced volume for the container is available at an early stage, the pressure level in the bag increases steeper during the filling process than in a conventional method, so that overpressure in the bag is achieved at a considerably earlier point in time , which causes an automatic bag venting. Since the venting rate of the container depends on the pressure difference between the interior of the bag and the environment, there is optimal ventilation due to the pressure level prevailing during the filling section. The venting of the container is significantly accelerated.

Applying the pressure prevailing in the sack over time, the area under the curve is a measure of the work of venting. This area, which refers to the period of the actual filling, is greater in the inventive method, so that according to the invention a faster filling can be achieved.

Experiences in a specific case have shown that overpressure is already reached there after about half of the otherwise required time, so that during the filling process an effective venting already takes place over a much longer period of time.

The volume is reduced towards the end of the filling process, in particular in the calming section after the filling process has ended, while the container is still arranged on the filling nozzle or the filling member. For this purpose, the previously existing venting pressure on the container is again increased and the pressing pressure adjusted to the available Volume and thus reduce the container volume by venting the container.

In particular, a high and in particular temporal constant pressing pressure is applied to the container immediately after switching off the conveying member, which leads to an increased venting of the container and thus a reducing volume of the container.

The measures can shorten the filling process and considerably reduce the required waiting time. In one specific case, the duration of the settling phase was reduced from about 20 seconds to 5 seconds, while the duration of the filling section remained constant at about 30 seconds, so that the time for the filling process could be reduced by 20 to 30%.

Preferably, at least one detection device is provided, which reduces the pressing pressure on the container when the predetermined amount for the volume available to the container is reached. The detection device may be provided in the form of a mechanical curve control or, in a preferred development, may be embodied as an electrical detection device which outputs a pick-off signal.

For example, the detection device may be designed as a limit switch in a simple case. If the volume of the container is predetermined reduced or reaches a predetermined level, the limit switch is actuated, whereupon the limit switch or a control device outputs the acceptance signal. Following the acceptance section is initiated and the container finally removed.

It is also possible that a plurality of limit switches or position switches is provided, one of which is selectable for the indication of the predetermined measure. It is also possible an adjustable limit switch or position switch to set the predetermined level, for example, depending on the material or container dependent.

In particular, the detection device detects a value that is approximately proportional to the volume that is available to the container. The detection device or an associated control device preferably outputs a decrease signal when the value has reached the predetermined level. Then the pressing pressure is reduced to the container and the container is removed.

In advantageous developments, the volume available to the container in the settling phase is reduced to a predetermined level. This value can be selected fixed and specified for all containers to be filled with a product.

It is also possible that the volume available to the container in the calming phase is reduced by a predetermined amount. For example, regardless of the starting width, which depends on the filling product and the dimensions of the bag, the width may be adjusted by e.g. 4 cm or 6 cm can be reduced. This offers advantages, especially if the product properties fluctuate.

It is also possible to reduce the available volume by a predetermined or adjustable percentage.

In particular, a venting pressure is exerted on the container from outside during at least part of the filling section, To reduce the volume available to the container already during filling and to promote the venting.

During the filling section, a predetermined pressure in the container is preferably built up quickly and then held approximately. The volume can be greatly increased at the end of the calming section, in particular after the calming phase in one step.

The available volume during the filling section essentially results from an equilibrium of the internal container pressure and the venting pressure which is applied from the outside.

Advantageously, a predetermined pressure in the container is built up quickly and then held approximately during the filling. The built-up pressure can be the maximum buildable pressure or a pressure that is selected while maintaining safety tolerances. In particular, the built-venting pressure is below the producible by the conveying member filling pressure.

In all embodiments and developments, the pressing jaws are preferably pressure-controlled, but may have a position detection or a position detection.

By the comparison with the venting pressure increased pressure in the calming section, the vent is reinforced, so that the calming section can be shortened.

The characteristic value for the weight of the container or of the contents contained in the container during the filling process can, in particular during filling or during the filling process be recorded periodically or continuously. In this case, the weight can be determined via a net method, and particularly preferably a gross method. It is also possible that a bag chair, on which the container is arranged, is part of the weighing system. Since the weights of the components involved are known, it is possible to deduce from the measured total weight on the current weight of the contents contained in the container back. Preferably, when the target weight of a container is reached, the feed of the bulk material is stopped. Also possible is a weight-dependent control of the filling process or the filling process, wherein the filling rate is reduced upon reaching a predetermined weight or weight fraction of the coarse flow rate to the Feinstromfüllrate. The filling rate can also be lowered continuously on reaching a predetermined weight or weight fraction up to a minimum filling rate in order to achieve optimum filling.

The reduction of the pressing pressure at the end of the calming phase can take place in particular abruptly or approximately abruptly. As a result, the available volume in the calming section is greatly increased in a short period of time. Also possible is a continuous increase in volume after reaching the predetermined reduced volume.

In all other embodiments, the volume available to the container can be initially limited by lateral limiting devices, pressing devices, press jaws the like, the pressing jaws or the like to increase the available volume of the container then at the end of the filling process and in particular at the end of the Be calming section to the outside. In preferred embodiments, the limiting devices act or pressing jaws or the like on the longitudinal sides of the container. In particular, the pressing jaws are pressure-controlled at least in the settling phase.

It is also possible that the volume available in the calming phase is predeterminedly reduced by a path-controlled movement of the pressing jaws.

In preferred developments of the invention, the volume available to the container is increased by up to 50% or more, in particular by up to 30%. Preferably, the volume increase is between about 3% and 20% and more preferably between about 5% and 15%. Depending on the material to be filled, the percentage of particularly fine and light fabrics may be even greater.

Preferably, after the stopping of the conveying member, the pressing pressure is applied to the container, since the pressure reduction in the preceding period is faster at higher pressures.

If towards the end of the settling phase there is an overpressure of e.g. 100 millibars so the internal pressure is about 1.1 bar. By increasing the volume by 10%, the overpressure contained in the bag can be completely reduced, for example. According to the invention, the waiting time and the calming section can be shortened considerably.

In all embodiments of the invention, a characteristic value for the inner bag pressure or the filling pressure in the container can be detected preferably by means of a pressure sensor. In particular, a characteristic value for the air pressure prevailing in the container is determined.

For example, a probe with a measuring channel can be provided on a filling element designed as a filling tube or filler neck, which extends into the interior of the container to be filled so that a sensor connected to the measuring channel acquires a characteristic value for the pressure prevailing in the container. In other embodiments, a characteristic value for the pressure prevailing in the container can also be derived via a sensor connected to the filling element or to the container.

Advantageously, the filling process as a whole or at least the filling process is controlled as a function of the determined characteristic value. This allows compliance with limits during the filling process. Preferably, the filling process is controlled such that a predetermined maximum pressure is not exceeded, e.g. to avoid a sack break. On the other hand, the conveying member is preferably controlled such that the pressure present in the container or in the bag is as close as possible to the maximum pressure in order to accelerate the filling process as a whole.

In preferred developments of the invention, the volume available to the container is varied at least over a period of time as a function of the determined characteristic value for the filling pressure or inner bag pressure prevailing in the container.

If a pressure sensor is provided for determining a characteristic value for the in-bag pressure prevailing in the container, the acceptance time of the container from the filling member or the filler neck can preferably be selected as a function of the inner bag pressure, to ensure that almost no material escapes during the decrease. For this purpose, the pressing jaws can be opened and the prevailing in the container bag pressure can be detected. If a suitable take-off pressure is present, the bag can be removed. Otherwise, the pressing pressure be rebuilt until a suitable take-off pressure results.

In all embodiments, in particular valve bags are filled, which are closed after the filling or can also be executed self-closing.

In all embodiments, a diaphragm pump is preferably used to convey the bulk goods. Although the diaphragm pump is basically a machine for the conveyance of liquids or gases, this system has also proven itself for the conveyance of free-flowing goods and in particular of free-flowing goods.

The operating principle of the diaphragm pump is similar to that of the piston pump, with the diaphragm pump being completely separated from the bulk material to be filled and the drive. The separation is achieved by a membrane, by which the moving mechanical components of the engine are shielded from the effects of the bulk material to be conveyed.

The actual mechanical drive of the diaphragm pump can conventionally be effected via an electric motor by means of a connecting rod fixed to the diaphragm or by means of suitably controlled compressed air.

Diaphragm pumps have the advantage over conveyor turbines that they have a lower dependence of the filling capacity of the pressure prevailing in the bag overpressure, so that the prevailing during the filling process increased pressures affect the flow rate only slightly.

Preferably, double diaphragm pumps are used, which can also be controlled by compressed air. For this purpose, a double housing is provided, which has a connecting rod two Containing connected membranes. The membranes are acted upon on the outside by the conveying bulk material and on its inside by compressed air. Over the connecting rod a valve is actuated which reverses the compressed air to the respective other membrane when an end position is reached. Such a diaphragm pump controlled by compressed air transfers the air pressure directly to the bulk material to be conveyed. By throttling the pressure, the transported bulk material can be adjusted well.

In all embodiments, in particular light and possibly also elastic bulk material having a density of less than 300 kg per m ³ or with a density of less than 300 g per dm ^{3 is} filled. Preferably bulk material is filled with a density of less than 250 kg per m ³ and in particular with a density between 30 and 150 kg per m ³ .

The device according to the invention for filling flexible containers formed as a valve sack is provided in particular for filling valve sacks with pourable goods and comprises a control device and at least one filling member with which a valve sack to be filled is filled by means of a filling process, in particular with the addition of air. The filling process comprises at least one filling section, a depressurization settling section and a take-off section. In the removal section of the valve bag is removable from the filling member. In this case, a pressing device is provided with which pressure can be exerted on the valve bag from the outside. The control device and the pressing device are suitable and structured to exert a venting pressure on the valve bag from the outside by means of the pressing device at least during at least part of the filling section, in order to reduce the volume available to the valve bag and, at least in the settling phase, press from outside onto the valve bag Apply valve bag to vent the valve bag and reduce the volume available to the valve bag until a detection device detects a predetermined reduction of the valve bag available volume, whereupon a decrease signal is output and the pressing pressure of the pressing device is reduced to the valve bag and the valve bag is removed from the filling member. In particular, the filling process can also be shortened by the volume available to the container being reduced by means of the pressing or limiting device during a substantial part of the filling process and greatly increased at the end of the calming section in order to increase the pressure prevailing in the container during the filling section and to circulate the calming section after the filling section.

Preferably, the pressing device has two pressing jaws, which can act on lateral areas of a container.

In particular, the detection device is suitable for determining a value for the volume available to the container, wherein the detected value is preferably approximately proportional to the volume which is available to the container. In particular, the detection device comprises at least one distance sensor or a position sensor or a displacement sensor. It is possible, e.g. an ultrasonic distance sensor or a laser distance sensor or other sensor capable of detecting a path or distance. It is possible with motor systems, e.g. an incremental encoder.

In preferred developments, at least one pressure sensor is provided with which a characteristic value for a pressure prevailing in the container can be determined. Preferably, a comparison device is provided which compares the prevailing pressure with a predetermined pressure and which triggers a decrease signal when the prevailing pressure is less than the predetermined pressure.

In all cases, preferably at least one diaphragm pump is provided for transporting the bulk material.

With the device according to the invention, which is particularly suitable for carrying out one of the methods described above, valve sacks can be effectively filled in particular, wherein the predetermined volume reduction after the filling section enables effective venting of the sacks.

A filling member according to the present invention is z. B. a filling tube on which a valve bag is plugged. The filling member is formed generally hollow and through the interior of the filled material to be filled is passed to get into the container. The transport of the filling material through the filling member is usually carried out by a conveying member. A conveying member in the sense of the present invention is an organ or a device for transporting the contents to be filled. For example, the conveying member may be formed as Doppelmembranpmpe. The use of conveyor turbines or other known in the art conveyor organs is possible. The conveying member may be part of the filling member, but may also be arranged separately and in particular in front of it.

Further advantages and possible applications of the invention will become apparent from the embodiments which are described below with reference to the accompanying figures.

Fig. 1

eine schematische Darstellung einer erfindungsgemäßen Vorrichtung;

Fig. 2

eine weitere erfindungsgemäße Vorrichtung in einer perspektivischen Ansicht;

Fig. 3

eine perspektivische Ansicht deines Sackstuhls für eine Vorrichtung nach Figur 1 oder 2;

Fig. 4

eine Vorderansicht des Sackstuhls nach Figur 3 mit einem angehängten leeren Sack;

Fig. 5

eine Vorderansicht des Sackstuhls nach Figur 3 mit einem gefüllten Sack nach dem Abschalten des Förderstroms;

Fig. 6

eine Vorderansicht des Sackstuhls nach Figur 3 mit einem gefüllten Sack nach dem Pressvorgang;

Fig. 7

eine schematische Schnittdarstellung durch ein Füllrohr einer erfindungsgemäßen Vorrichtung; und

Fig. 8

eine stark schematisierte Darstellung des Füllstatus, Füllgewichts, Sackinnendrucks und des dem Sack zur Verfügung stehenden Volumens über der Zeit während eines Füllprozesses.

Show:

Fig. 1

a schematic representation of a device according to the invention;

Fig. 2

a further device according to the invention in a perspective view;

Fig. 3

a perspective view of your sack chair for a device according to FIG. 1 or 2 ;

Fig. 4

a front view of the sack chair after FIG. 3 with an attached empty sack;

Fig. 5

a front view of the sack chair after FIG. 3 with a filled bag after switching off the flow rate;

Fig. 6

a front view of the sack chair after FIG. 3 with a filled bag after the pressing process;

Fig. 7

a schematic sectional view through a filling tube of a device according to the invention; and

Fig. 8

a highly schematic representation of the filling status, filling weight, internal bag pressure and the volume available to the bag over time during a filling process.

With reference to the FIGS. 1 to 8 Now, an embodiment of the invention will be explained. In the FIG. 1 shown inventive device 1 is executed here in the embodiment as a packing machine 1 with a single filling member in the form of a filling tube 3.

The packing machine 1 is used to fill sacks 4 with pourable filling goods 18 and is executed here fully automatically in the embodiment. It is also possible to form the packing machine rotating and distributed with several over the circumference arranged to provide filling organs. Likewise, manual hand attachment is possible.

The packaging machine 1 comprises a frame 8 and a filling element 3 designed as a filling member, on which the valve bags 4 are pushed with openings 25. An operating unit 22 serves to operate and display the status of the packaging machine 1. With a suction device 21, e.g. sucked out when sack changing trickling product.

Valve bags 4 are stored in a empty bag magazine 50. For filling a valve bag 4 is gripped and lifted. In Fig. 1 is the bag bottom 4a of an empty valve bag 4 recognizable. The valve bag 4 is pushed onto the filling tube 3 with the attachment device 51 (or by hand). For this purpose, the track unit 52 is moved in the direction of the filling tube 3.

After filling and removal of the valve bag 4, the valve is closed. It may also be e.g. be welded. The sacks 4 are thrown onto the discharge device 26. In the subsequent discharge line, the actual weight of the valve bags 4 can be checked again before the valve bags 4 are removed.

As in FIG. 1 illustrated, the filling tube 3 is associated with a pressing device 5, each comprising two pressing jaws 5a and 5b. When attaching the pressing jaws 5a and 5b are moved apart, so that the valve bag 4 can be easily pushed onto the filling tube 3. Subsequently, the pressing jaws 5a and 5b are moved from the side to the valve bag, so that the volume available for the valve bag 60 (see. FIG. 4 ) is practically already reduced from the beginning of the filling process and is smaller than the possible bag volume of the valve sack. 4

A highly schematic and only principally applied course of the bag weight 30 and of the pressure prevailing in the bag 31 is inter alia in Fig. 8 represented over time T.

At the time t0 of the filling section 40 starts. The empty bag 4 is attached and the pressing jaws 5a and 5b are driven together with the compressed air cylinder 6 maximum, so that the volume available for the bag 60 starting from its starting volume 61 its minimum value 62 for Time t1 occupies. At the same time, the filling process starts and filling material 18 is filled. The bag 4 expands due to the filled product 18 and takes up the available volume, but that is initially limited by the pressing jaws 5a and 5b to the minimum volume 62. Subsequently, an overpressure builds up in the valve bag 4, which is typically up to 100 or 250 millibars and may even be greater and depends on the filling material and the other conditions. At time t2, an approximately stationary state is reached. In particular, the local in-bag pressure 31 or overpressure in the bag corresponds approximately to the venting pressure 32 of the pressing jaws 5a and 5b applied from the outside in this filling section 40.

Until reaching a predetermined weight at time t3 is filled with the coarse flow S1. This is followed by the fine flow S2. At time t4, the intended weight 30a is reached, the product supply is stopped, and the filling portion 40 is finished.

This is followed by the calming section 41. At time t4, the pressure exerted by the pressing jaws 5a and 5b from the outside on the pressing pressure 34 is preferably increased directly. The pressing pressure 34 of the pressing jaws is preferably applied here by the compressed-air cylinder 6. As a result, the pressure in the bag rises from the pressure 32 to the pressure 34 and remains there approximately constant. At the same time vented the valve bag 4 and the bag volume 2 and the bag available volume 60th decreases along the curve 64. The high internal pressure causes a rapid and effective venting of the bag. 4

The volume available to the bag decreases until the time t5 when the available predetermined volume 65 is reached, which may be predetermined as an absolute value, or results as a volume difference 67 to the volume at time t4.

The reaching of the available predetermined volume 68 is detected by the detection device 70, which outputs a signal which is processed by the control device 14. The control device 14 outputs a decrease signal and the acceptance section 42 is initiated. The pressing pressure 34 of the pressing jaws 5a, 5b is reduced. The opposite of the ambient pressure still increased bag pressure ensures that the pressing jaws 5a and 5b are driven up. As a result, the volume 60 available to the valve bag 4 between the pressing jaws 5 a and 5 b is increased rapidly to the final volume 66.

Alternatively, the pressing jaws 5a and 5b can also be actively opened by the cylinder 6, so that the available volume 60 is increased abruptly or almost abruptly to the final volume 66.

The valve bag 4 now assumes an increased volume due to the overpressure prevailing in the interior of the valve sack 4, as a result of which the pressure prevailing in the interior of the valve sack 4 is correspondingly reduced. This leads to the fact that directly after the opening of the press jaws 5a and 5b, the inner bag pressure 31 is equal to the withdrawal pressure 36, so that practically immediately after the time t5, the bag can be removed. The calming portion 41 is shortened considerably.

Due to the filling process, the necessary waiting time until the valve bag 4 can be removed from the filling tube 3, significantly reduced, so that the filling speed compared to conventional Filling process is increasing. At the same time, a material discharge during the removal of the filling tube 3 is avoided, since the internal pressure is reduced, so that the valve bags 4, the packaging machine 1 and the environment are not so much or in particular not polluted. It is possible to control the filling process so that usually no product or only a very small proportion of product exits the valve bag 4.

With the packing machine 1 according to the invention, preferably lightweight materials and in particular aerosils, carbon black and other light products are filled. However, it is also possible to use other products such as To fill cement or the like with the packaging machine 1 according to the invention.

According to previous experience in filling with light filling materials, such as. Fumed silica, results in a significant increase in performance at the same time higher weight accuracy. While the waiting time after the end of the filling process, while the overpressure in the bag is reduced, was about 15 to 20 seconds for a filling material in conventional machines, in the system according to the invention the bag can be almost or even removed directly after the pressing pressure the volume Predetermined reduced and the bag available volume was increased. The time saved in this example is about 12 to 17 seconds per bag. With an average duration of filling of about 30 seconds, this means a shortening of the filling process from about 50 seconds to about 35 seconds and thus a very significant increase in plant capacity by about 20 or 30 - 40%. With heavier materials or with materials that are filled with a lower air content, a lower performance increase may occur.

In FIG. 2 a further embodiment of a packaging machine 1 according to the invention is shown in a perspective view, which is designed here as a stationary machine and also as a non-rotating system. The bag chair 20 is part of weighed system in the so-called gross weighing method, in which the bag chair 20 and the pressing device 5 and the valve bag to be filled with 4 are weighed to from the determined weight on the contents contained in the valve bag 4 18 (see. Fig. 7 ), since the weights of the sack chair 20 and the other components involved are known.

The pressing device 5 in turn comprises a right pressing jaw 5a and a left pressing jaw 5b, which are arranged approximately parallel to each other and spaced from each other in the starting position and which are pivotally mounted here at the lower ends of pivot axes 7. The two pressing jaws 5a and 5b are connected to each other at the upper ends via an upper linkage 5d, on which a drive 6 is arranged, which is designed here as a motor or compressed air cylinder. By actuating the motor 6, the upper distance between the pressing jaws 5a and 5b is reduced, so that the volume 60 present between the pressing jaws 5a and 5b is influenced, as in particular also in the illustration FIG. 4 is recognizable. With the in Fig. 6 visible detection device 70, which is designed for example as a displacement sensor, a path-controlled control of the pressing jaws 5a and 5b take place. As an alternative to the motor 6, another actuator for actuating the pressing jaws may be provided, which comprises, for example, a compressed air cylinder or hydraulic drive.

Instead of the rotatable bearings at the lower ends of the pressing jaws 5a and 5b, which are each provided with pressing plates 5c, the lower linkage 5e can be made adjustable in length via a pneumatic cylinder or a motor 6 or other actuator.

By length-adjustable linkage 5d and 5e, a parallel displacement of the pressing jaws 5a and 5b can be achieved.

According to the invention, the pressing jaws 5a and 5b of the bag chair 20 at the beginning of the filling process or the filling process in such a way moved the valve bag 4 that they initially significantly reduce the available bag volume 60 during filling, for example, by 30% or more. This means that for a weight size of eg 10 kg only a reduced volume is available. Now, if the valve bag 4 has reached its desired weight and the filling process is thus completed, the valve bag 4 is initially under the usual pressure of eg 100 or 250 millibar or the like.

At this moment, the two lateral pressing jaws are brought together with increased pressing pressure. This increases the deaeration rate and the sack volume decreases. The increased pressing pressure is reduced only when the volume available to the bag has been predetermined reduced. For example, the lateral pressing jaws 5a and 5 can be moved towards each other to a predetermined distance. It is also possible to adjust the width of the bag by a predetermined amount of e.g. 2, 4, 6 or 8 cm is reduced. The predetermined amount may depend on the product to be filled and the bag dimensions. Only when the predetermined volume reduction has been reached is the pressing pressure 34 reduced or switched off so that the volume available to the valve bag 4 increases virtually abruptly and thus the overpressure in the interior of the bag is compensated.

After moving apart of the pressing jaws 5 a and 5 b, the valve bag 4 can therefore be removed as a rule, without a detrimental product loss occurs during the decrease. Consequently, this system allows a high filling performance, since only a small residence time after the filling process is required, with no 18 or only small quantities are discharged during the decrease.

It is also possible that the pressing jaws 5 a and 5 b are first opened after the filling process has ended and then again lightly pressed against the sack 4 in order to prevent the bag from being removed by the bag removal device 24 (cf. Fig. 3 ) to support. At the in Fig. 3 illustrated embodiment is the bag chair 20 including the pressing device 5 and the bag removal device 24 part of the weighed system, which is weighed during filling to determine the filled product weight and to control the filling accordingly. The bag chair 20 is suspended on the frame 8 via the counter links 23 and is weighed via the load cell (not shown) attached to the load cell attachment 26.

In preferred embodiments, the packing machine comprises a double-diaphragm pump 16 for conveying the filling material 18. A double-membrane pump 16 is suitable in particular for filling light filling materials or filling material 18. The filling performance of filling materials having a bulk density of less than 100 g per dm ³ at about 60 bags per hour and filler, but can also be larger or smaller.

It should be noted that according to the invention not only single or batch packing machines can be provided, but it can also rotary packing machines are used with more than one filling tube or series packing machines with several in-line filling tubes.

In the filling process, the control of the filling process is carried out by a balance control, which controls the filling speed in dependence on the bag weight 30 or of the filling weight already present in the valve bag 4.

In Fig. 4 a bag chair 20 is shown in a front view with an attached empty bag 4. The available volume 60 is reduced to a minimum volume 62 since the pressing jaws 5a and 5b have been retracted. The distance 54 on the cylinder 6 is a measure of the available bag volume. The distance 54 is in the in Fig. 4 shown state, since the available volume was reduced to the minimum volume 62. The sack volume 2 is still almost zero, since there is still no product 18 in the bag. 4 was filled. With the beginning of filling, the actual bag volume 2 quickly reaches the available volume 62, whereupon the bag inner pressure 31 rises to the venting pressure 32 of the pressing jaws 5a and 5b. As the filling progresses, the pressing jaws 5a and 5b are pushed apart and the available volume 60 and the sack volume 2 increase until the intended end or sack weight 30a is reached.

In Fig. 5 the filled state is shown, wherein the available volume 60 reaches about its intermediate maximum. Depending on the contents 18 and filling conditions, the volume of the bag here has its maximum or even earlier during the filling with the fine stream S2.

Subsequently, the pressing jaws 5a and 5b are pressed with increased pressing pressure 34 on the side surfaces of the bag 4 and the bag 4 is due to the high pressing pressure 34 vented conditionally quickly. The actual bag volume decreases until the available volume 60 has been predeterminedly reduced and either decreased by a predetermined volume difference 67 or by a fraction, or reaches a predetermined minimum available volume 68. This condition is in Fig. 6 shown. The distance 56 is significantly smaller than the distance 55 in the bulging state, the in Fig. 5 is shown.

The distances 54 to 56 are here approximately proportional to the available volume 60. The respective current distance is detected here by the detection device 70, which works as a displacement, distance or length measuring device and a measure of the distance of the two pressing jaws 5a and 5b detected. Then the pressing process is terminated and the decrease of the bag 4 is initiated. The termination of the pressing operation is initiated here when the distance 56 is reached, which represents a certain available minimum volume 68. In other embodiments, a laser or ultrasonic distance sensor or other displacement or length sensor may be provided.

In FIG. 7 a schematic cross section through a filling tube 3 is shown. In this filling tube 3, at least one pressure sensor 10 is additionally provided, with which a characteristic value for the pressure prevailing in the valve bag 4 pressure can be detected.

In FIG. 7 the filling tube 3 is shown cut, on which a valve bag 4 is pushed with its opening 25. The valve bag 4 is held with a mounted on an outer side 3 a of the filling tube 3 Blähmanschette 27 and sealed to the environment. In the inflated state, the inflation sleeve 27 engages an inner wall 28b of a portion 28 of the valve sack 4 which serves to fasten the valve sack 4 to the filling tube 3.

By means of the pressing device after the Figures 3 - 6 For example, the volume 60 available for the valve bag 4 is reduced even before the beginning of the filling section.

Furthermore, a value characteristic of the pressure in the valve bag 4 is received via the pressure sensor 10 during the filling process. In this case, the pressure sensor 10 may be arranged in a region 3 c of the filling tube 3, which directly adjoins a region 3d occupied by the section 28 of the valve sack 4. The pressure sensor 10 extends through a wall of the filling tube 3, so that it receives the pressure in the interior of the filling tube 3, which essentially corresponds to the pressure prevailing in the valve bag.

Alternatively, a pressure sensor 10 may be provided which receives the pressure prevailing in the interior of the bag via a pressure receiving opening 9 or a measuring channel or a measuring line 13. The pressure-receiving opening 9 may be provided, for example, in a front region of the filling tube 3 in the vicinity of the outlet opening for the filling material 18. The measuring line 13 may have a first channel 13 as a running portion in the filling tube and a second portion 13 b, which is designed as a flexible or rigid conduit and is connected to the pressure sensor 10. Because pressure disturbances propagate at the speed of sound, the measuring line 13 can have a considerable length.

The pressure values measured with the pressure sensor 10 are temporarily stored in the assigned digital evaluation unit 11 and transferred to a central control unit 14. Based on the data measured by means of the weighing system 12 and by means of the pressure sensor 10, the filling process is controlled. The measured values measured by the weighing device 12 are sent to an electronic processing unit 15, which is connected to the central control unit 14, which controls the conveying member 16.

For special substances or in special situations, air may be supplied via an air supply 17, e.g. Caking to solve.

The filling process works as follows: After attaching a valve sack 4 by hand or with a slip-on machine to a filling tube 3, the valve sack 4 is fixed by means of the inflation sleeve 27 and the pressing jaws 5a and 5b are brought to the sack to its available volume to limit. Subsequently, the filling process is started, which is controlled by the electronic control unit 14 and in which the filling material 18 and at the same time an air portion 19 are introduced into the bag 4.

The filling material 18 supplied to the conveying member 16 from a silo or the like is introduced through the filling tube 3 into the valve bag 4. The amount of filled material or filling material 18 is continuously detected by the weighing device 12 shown only schematically and the measured values are forwarded to the processing unit 15 and the control unit 14.

At the same time, the pressure prevailing in the valve bag 4 pressure can be detected. If the pressure in the valve bag exceeds a predetermined limit, the filling process is slowed down to avoid bursting of the valve bag 4. Conversely, the filling speed be increased when the pressure prevailing in the valve bag is less than a predetermined pressure.

The position of the pressing jaws can be controlled as a function of the current bag weight 30 and the determined pressure in the valve bag 4. It is possible, e.g. that the pressing jaws 5a and 5b first reduce the volume available to the bag when a predetermined proportion of e.g. 30 or 50% of the intended capacity was filled in the bag. It is also possible for the pressing jaws 5a and 5b to approach one another continuously after the end of the filling operation in order to reduce the volume 60 available to the bag continuously before the bag volume is finally increased before it is taken off.

Preferably, the pressing jaws 5a and 5b are moved apart after the end of the pressing process, so that the pressure in the bag interior drops rapidly or even almost abruptly. Now, if the over-pressure determined inside the bag falls below a predetermined or selectable value, the bag is removed. Since there is no or only a slight overpressure during the removal, only very little or no filling material 18 is blown out of the bag during the removal, so that the sacks 4 and the packaging machine 1 remain considerably cleaner. With the pressure sensor 10, it becomes possible to check the bag inner pressure 31 before the take-off so as to surely prevent the discharge of the filler 18 at the time of take-off.

Claims (15)

1. A method for filling valve bags (4) with loose materials (18), wherein by means of a filling element (3) a valve bag to be filled (4) is filled by means of a filling process, which filling process comprises at least a filling stage (40), a settling stage (41) and a discharge stage (42), wherein during the filling stage (40) at least one loose material (18) is filled into the valve bag (4) and during the settling stage (41) at least one settling phase (37) for venting is provided, and wherein during the discharge stage (42) the valve bag is discharged from the filling element (3), characterized in that at least during part of the filling stage (40) a venting pressure (32) is externally applied to the valve bag (4) by way of at least one squeezing device (5) so as to reduce the volume (60) available to the valve bag (4), and that at least in the settling phase (37) the at least one squeezing device (5) applies a squeezing pressure to the valve bag (4) for venting the valve bag (4) and reducing the volume (60) available to the valve bag (4) until a predetermined reduction of the volume available to the valve bag is achieved, whereupon the squeezing pressure (34) of the squeezing device (5) on the valve bag (4) is reduced and the valve bag (4) is discharged from the filling element (3).
2. The method according to claim 1, wherein at least one detector device (70) captures a value for the volume (60) available to the package and emits a discharge signal when a predetermined reduction is achieved, whereupon the squeezing pressure on the valve bag (4) is reduced and the valve bag (4) is discharged.
3. The method according to claim 1 or 2, wherein the detector device (70) captures a value approximately proportional to the volume (60) available to the valve bag (4).
4. The method according to claim 1, 2 or 3, wherein the predetermined reduction is achieved when in the settling phase (37) the volume (2) available to the valve bag (4) is reduced to or by a predetermined measure.
5. The method according to any of the preceding claims wherein during the filling stage (40) a specified venting pressure (32) is rapidly built up in the valve bag (4) and subsequently roughly maintained.
6. The method according to any of the preceding claims wherein the volume (60) in the settling stage (41) is expanded greatly in one step.
7. The method according to any of the preceding claims wherein a parameter for the weight of the valve bag (4) is captured during the filling stage (40) and as the target weight (30a) of the valve bag (4) is reached, feeding of the material (18) is cut off.
8. The method according to any of the preceding claims,
   wherein the pressure is applied to the valve bag (4) externally by means of squeezing jaws (5a, 5b) of a squeezing device (5) which act in particular on the longitudinal sides of the valve bag (4) and/or wherein the squeezing jaws (5a, 5b) are pressure-controlled at least in the settling phase (37) and/or wherein the available volume is reduced in the settling phase (37) as predetermined by means of a distance-controlled displacement of the squeezing jaws (5a, 5b).
9. The method according to any of the preceding claims,
   wherein a pressure sensor (10) captures a parameter for the internal bag pressure (31) in the valve bag (4) and the filling process is controlled at least in part in dependence on the internal bag pressure (31) and/or wherein the discharge time (t5) is selected in dependence on the internal bag pressure (31) wherein in particular after reduction of the squeezing pressure (34) the internal bag pressure (31) in the valve bag (4) is checked and as it falls beneath a specified discharge pressure (36) the discharge time (t5) is selected.
10. The method according to any of the preceding claims,
    wherein the squeezing jaws (5a, 5b) apply a slight pressure on the valve bag (4) at discharge of the valve bag (4) to assist in discharge.
11. An apparatus for filling valve bags (4) with loose materials (18), comprising a control device (14) and at least one filling element (3) for filling a valve bag (4) to be filled by means of a filling process, which filling process comprises at least a filling stage (40) for filling the valve bag (4), a settling stage (41) with at least one settling phase (37) for venting and a discharge stage (42), and wherein in the discharge stage (42) the valve bag (4) can be discharged from the filling element (3) wherein a squeezing device (5) is provided which can apply external pressure on the valve bag (4), characterized in that the control device (14) and the squeezing device (5) are suitable and structured such that at least during part of the filling stage (40) a venting pressure (32) is externally applied to the valve bag (4) by means of the squeezing device (5) so as to reduce the volume (60) available to the valve bag (4) and at least in the settling phase (37) an external squeezing pressure (34) is applied to the valve bag (4) for venting the valve bag (4) and reducing the volume (60) available to the valve bag (4), until a detector device (70) detects a predetermined reduction of the volume available to the valve bag (4), whereupon a discharge signal is emitted, the squeezing pressure (34) of the squeezing device (5) on the valve bag (4) is reduced and the valve bag (4) is discharged from the filling element (3).
12. The apparatus according to the preceding claim wherein the squeezing device (5) comprises a pair of squeezing jaws (5a, 5b) which can act on areas on the sides of a valve bag (4) disposed on the filling element (3).
13. The apparatus according to any of the preceding claims 11 or 12, wherein the detector device (70) is suitable to determine a value for the volume (60) available to the valve bag (4) which determined value is preferably approximately proportional to the volume (60) available to the valve bag and/or wherein the detector device (70) comprises at least one distance or displacement sensor.
14. The apparatus according to any of the preceding claims 11 to 13 wherein at least one pressure sensor (10) is provided by means of which a parameter for a pressure prevailing in the valve bag (4) can be determined and wherein preferably a comparator device (14) is provided which compares the prevailing pressure (31) against a specified discharge pressure (36) and which triggers a discharge signal when the prevailing pressure (31) is beneath the specified discharge pressure (36).
15. The apparatus according to any of the preceding claims 11 to 14, wherein at least one diaphragm pump (16) is provided for conveying the bulk material (18).

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