Apparatus and method for emptying containers, with control of a drive torque

Abstract

An apparatus is provided for emptying containers, including first and second holding devices which are suitable for holding first and second regions of containers that are to be emptied, wherein the second region is a distance from the first region, including a movement device which suitable for moving the first holding device towards the second holding device to compress the container located between the first holding device and the second holding device, and including a withdrawal device which has a flow connection to the interior of the container and via which liquid located in the container can be withdrawn as a result of compression of the container, including a drive device for driving the movement device, and including a control device which controls the relative movement of one holding device relative to the other holding device as a function of an internal pressure inside the container.

Claims

1. An apparatus for emptying containers, comprising: a first holding device which is suitable for holding a first region of a container that is to be emptied, a second holding device which is suitable for holding a second region of the container that is to be emptied, wherein the second region is at a distance from the first region, a movement device which is suitable for moving the first holding device towards the second holding device in order to compress the container located between the first holding device and the second holding device, a withdrawal device which has a flow connection to the interior of the container and via which liquid located in the container can be withdrawn as a result of compression of the container, a drive device for driving the movement device, wherein the movement device has a first drive spindle, the rotational movement of which brings about a movement of one holding device relative to the other holding device, and wherein a revolving element connects the drive device to the first drive spindle, and further wherein the detection device detects a force acting on the revolving element, a control device which controls the movement of one holding device relative to the other holding device as a function of an internal pressure inside the container, wherein the control device is configured in such a way that it controls the movement of one holding device relative to the other holding device as a function of a drive torque of the drive device, and a detection device adapted to directly detect the drive torque of the drive device acting on the movement device, wherein the detection device directly measures the drive torque instead of directly measuring the internal pressure in the container.

2. The apparatus according to claim 1, wherein the movement device has a second drive spindle and a rotational movement of the second drive spindle is coupled to the rotational movement of the first drive spindle.

3. The apparatus of claim 1, wherein the revolving element comprises at least one of a toothed belt and a revolving chain, further wherein both the drive device and the first drive spindle act on the revolving element.

4. The apparatus of claim 3, wherein the revolving element is driven by a gear.

5. The apparatus of claim 1, wherein the detection device is included in the drive device and is selected from at least one of a rotary encoder and a current measuring device.

6. The apparatus of claim 1, wherein the control device is configured to keep the drive torque and the internal pressure within predefined limits.

7. The apparatus of claim 1, wherein the movement device comprises an entire drivetrain from the drive device to at least one holding device, including the revolving element and the first drive spindle.

8. The apparatus according to claim 2, wherein the movement device has a third drive spindle, and the rotational movement of the first, second, and third drive spindles brings about a movement of one holding device relative to the other holding device.

Description

BRIEF DESCRIPTION

(1) Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

(2) FIGS. 1a-1c show three diagrams of an apparatus in different operating states;

(3) FIG. 2 shows a plan view of an apparatus;

(4) FIG. 3 shows a diagram of an apparatus in a further embodiment;

(5) FIG. 4 shows a diagram of an apparatus in a further embodiment;

(6) FIG. 5a shows a diagram to illustrate a relationship between a drive torque and a container pressure; and

(7) FIG. 5b shows a diagram to illustrate measurements of a relationship between a torque and a container pressure.

DETAILED DESCRIPTION

(8) FIGS. 1a to 1c show three side views of an apparatus 1 according to embodiments of the invention. Here, a container 10 is provided which is arranged between a first holding device 2 and a second holding device 4. The holding device 2 serves to hold a mouth region 10a of the container including a cap 10c of the container, and the holding device 4 serves to hold a base region 10b (this is hidden). In order to withdraw liquid, the second holding device 4 is moved upwards and thus towards the first holding device 2. In this way, liquid can be withdrawn from the container via a withdrawal device 40, which in particular has a withdrawal hose 42. References 32 and 34 denote two drive spindles, the rotation of which brings about here a movement of the second holding device 4 in the upward direction. A third spindle is also provided, but this is not visible in the figures.

(9) Reference 8 denotes a drive device, in particular a drive motor, which drives the spindles 32 and 34 here via toothed wheels 33 and 35 and a drive belt 24, which serves here as force transmission means.

(10) FIG. 1b shows the apparatus of FIG. 1a in a further operating state. Here, the second holding device 4 is already halfway up the spindles 32 and 34 and thus the container 10 has already been partially rolled. It can be seen here that in particular the first holding device 2 has a stamp 26, the cross-section of which is smaller than a cross-section of the container, so that the mouth region having the cap 10c can be rolled into the container. In this way, very substantial emptying of the container is possible.

(11) In the situation shown in FIG. 1c, the second holding device 4 has already been moved almost completely towards the first holding device 2 and the container has thus been almost completely emptied.

(12) FIG. 2 shows a plan view of an apparatus according to the invention in a first embodiment. It is once again possible to see here the container 10 having a container cap 10c. It is also possible to see three drive spindles 32, 34 and 36, which are respectively coupled to toothed wheels 33, 35 and 37. These toothed wheels are driven by the revolving force transmission means 24, which is embodied here as a toothed belt. Reference 8 denotes a drive device, and reference 9 denotes a gearing via which a toothed drive wheel 18 is driven, which in turn drives the force transmission means 24. In this embodiment, a torque detection may be provided within the drive device 8, for example a drive torque may be detected via a rotary encoder or also via a current measuring device which detects a current that is necessary for driving the drive device 8.

(13) A control device can control the drive device 8 as a function of this drive torque. The control may be carried out in such a way that the drive torque (and thus also the pressure inside the container) always lie within predefined limits. Reference 6 denotes in its entirety the control device which controls the relative movement of one holding device relative to the other holding device. Preferably, this control device controls the drive device 8.

(14) Reference 20 denotes in its entirety the movement device which serves for achieving the relative movement between the first holding device 2 and the second holding device 4. This movement device 20 preferably comprises the entire drivetrain from the actual drive device to at least one holding device, that is to say in particular including the force transmission means and the drive spindles.

(15) Preferably, the drive torque of the drive device is determined via the effect of this drive torque on at least one element of said drivetrain.

(16) FIG. 3 shows a further embodiment of the present invention. In this embodiment, once again the three drive spindles are provided which bring about the emptying of the container and move the holding devices towards one another. In this embodiment, a force measuring device or a sensor device 62 is provided. This may be, for example, an electric force sensor, such as a piezo element or a strain gauge. Reference 28 denotes a carrier, by means of which the drive device 8 is mounted here in a pivotable manner. When the drive torque or the force necessary to compress the container increases, this carrier 28 would pivot to the left, as illustrated by the arrow, and accordingly would load the force measuring device 62. Reference 66 denotes a regulating device which regulates the motor or the drive device 8 as a function of a signal output by the force measuring device 62. The elements described here represent in their entirety the control device 6.

(17) FIG. 4 shows a further embodiment of the apparatus according to the invention, wherein here a relatively simple force switch is provided. First, a spring device 72 is provided which biases the carrier 28 counter to the arrow direction in FIG. 4, that is to say to the right. When the drive torque increases, the carrier 28 will once again pivot to the left and in this case can trigger a switching device 74 and thus for example stop the drive device 8. As soon as the drive torque decreases again, the switch 74 can be closed again and the motor will again be actuated.

(18) Within the context of experiments carried out by the applicant, use was made of an electric force sensor having a measurement range between 0 and 2 kN. The lever length of the carrier 28 was selected as 10 mm. The three spindles 32, 34 and 36 compress the container 10, wherein a pitch of the spindles is advantageously between 2 mm and 10 mm, particularly preferably between 3 mm and 8 mm and particularly preferably between 4 mm and 6 mm. The drive takes place here, as shown, via the force transmission device or the toothed belt 28 without any further gear reduction. In this way, for different pressures inside the container, the torque was determined for maintaining the pressure in the container on the one hand and on the other hand for increasing said pressure or for maintaining the pressure when pressing against an overpressure valve.

(19) Due to the efficiency of the spindles and the resistance when pressing against an overpressure valve (which corresponds to the dispensing), these values differ, which in turn leads to a hysteresis effect. This hysteresis effect is useful so that the drive device 8 does not switch on and off as frequently. Therefore, as mentioned above, the pressure inside the container is also determined and/or regulated by means of a torque on the drive spindles 32, 34, 36 and/or the drive device. Preferably, as mentioned above, an electrically measuring force measurement system is provided, which is used for evaluation and regulation purposes.

(20) Overall, this is a very simple and accurate method for measuring the container pressure or for controlling the drive device as a function of the container pressure, without making contact with the product itself. This effect can also be used for safety reasons in a dispensing system so that, due to a maximally achievable torque, the container pressure can never rise above a bursting pressure. Different methods are conceivable for limiting the torque of the drive device, both electrical and electronic methods and also the embodiments shown in FIG. 3 or 4.

(21) FIGS. 5a and 5b schematically show the relationships between the measured force and the container pressure. The force and thus the torque necessary for rolling the container under pressure and for maintaining the pressure within the rolled container can be determined at a measuring device, for example the measuring device 62 (cf. FIG. 3). Here, the tensile force (FZ) on the container can be obtained as follows:
FZ=(M*2*):(S*)

(22) Here, M denotes the torque, S denotes the spindle pitch and denotes the spindle efficiency.

(23) FIG. 5a shows the relationship between the container pressure and the torque. The left-hand diagram shows the relationships for the holding torque and the right-hand diagram 5b shows the relationships for the force on the container. From the values measured by the measuring device 62, for example voltage values, it is possible to deduce a force, and from this force it is in turn possible to deduce a torque, and from the torque it is in turn possible to deduce the force on the container. It has been shown that the force when rolling the container is considerably higher than the holding force or the theoretical force. This is based on the one hand on the efficiency of the spindles and on the other hand on the force that is necessary in order to press the air through an overpressure valve in order to keep the pressure constant. In the case of the measurement, the voltage rise on the force sensor was 145 mV/bar. With such a structure, the voltage can be accurately determined to approximately 20 mV at a pressure of 2.5 bar. This corresponds to a pressure change of approximately 140 mbar at this pressure. The pressure can thus be accurately regulated to 0.14 bar using the apparatus according to the invention. This accuracy can be increased even further with an optimized torque support or an optimized carrier 28.

(24) Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

(25) For the sake of clarity, it is to be understood that the use of a or an throughout this application does not exclude a plurality, and comprising does not exclude other steps or elements. The mention of a unit or a module does not preclude the use of more than one unit or module.

LIST OF REFERENCES

(26) 2 first holding device 4 second holding device 6 control device 8 drive device 9 gearing 10 container 10a mouth region 10b base region 10c cap 18 toothed drive wheel 20 movement device 24 drive belt 28 carrier 32, 34, 36 drive spindles 33, 35, 37 toothed wheels 40 withdrawal device 42 withdrawal hose 62 sensor device/force measuring device 66 regulating device 72 spring device 74 switching device