EP3440010B1 - Emptying device for viscous materials, and method for same - Google Patents

Description

I. Field of application

The invention relates to the emptying of highly viscous, ie pasty, substances from delivered containers, in particular barrels.

II. Technical background

When processing highly viscous substances, e.g. B. in the adhesive technology or cosmetics industry, there is often the problem that these substances or their base materials are delivered in transport containers such as 200 I-drums or in 20 I-buckets and the viscous material from there to a consumer, for example a dispensing gun or a mixer.

In the following, only one barrel is mentioned, which for the purposes of the present invention, however, should include all containers open on one side, because z. B. in the case of a cartridge, the front side, which is open in principle, is usually closed by an axially movable, tightly closing, stopper, and in addition the cartridge usually has a removal opening on the opposite front side.

The removal from the container and the transport to the remote consumer should take place automatically and as required, and one if possible residue-free emptying of the barrel without time-consuming manual reworking.

Due to the properties of the viscous material, it is often not permissible to heat it before it is removed and transported via pipes in order to increase its flowability.

In this context, so-called. Barrel presses are already known in which a press plate is placed on the viscous material in the barrel to be emptied, which z. B. in the middle has a through opening to which a delivery line for the viscous material is connected.

This pressing plate is designed to fit tightly on its outer circumference relative to the inner circumference of the barrel. By pressing down the pressure plate with sufficient force and corresponding to the path, the viscous material is pressed into the delivery line and delivered in this way to the consumer removed from the barrel in the desired quantity and with sufficient pressure at the consumer, depending on Length of the delivery line in the course of which one or more pumps can also be arranged.

• Zum Einen steigt der Kraftaufwand zum Herabpressen der Pressplatte mit zunehmender Viskosität, also Zähigkeit, des zu fördernden Materials stark an, sodass gerade über weitere Förderstrecken ein Fördern von relativ zähem, hochviskosem, Material ohne eine zusätzliche Pumpe in der Entleervorrichtung oder im Verlauf der Förderstrecke kaum möglich wird.
• Ein weiteres Problem besteht darin, dass beim Aufsetzen der Pressplatte auf das viskose Material unter der Pressplatte Luft eingeschlossen wird, die beim Fördern des Materials in die Förderleitung gelangt, was grundsätzlich unerwünscht ist, da das Material vom Verbraucher häufig genau dosiert ausgebracht werden soll, und diese Dosierung bei in der Förderleitung befindlichen Luftblasen nicht mehr möglich ist, und dadurch ein z. B. erzeugter Kleberauftrag lückenhaft und damit fehlerhaft werden kann.

• Des Weiteren wäre es zur Verringerung der notwendigen Presskraft gerade bei hochviskosen Materialien sinnvoll, das Fließen des Materials in die Förderleitung hinein zu begünstigen durch eine kegelförmige Ausbildung der Pressplatte. Dies jedoch führt zu einer hohen Restmenge, die in dem Fass gegen Ende der Entleerung verbleibt.
• Ferner muss vermieden werden, dass durch die relativ hohen Kräfte auf die Pressplatte die Pressplatte oder der Antrieb der Pressplatte beschädigt wird, wenn die Pressplatte den Boden des Fasses erreicht und der Antrieb nicht rechtzeitig abgestellt wird.
• Ein weiteres Problem besteht darin, dass mit zunehmender Viskosität des Materials der Druckverlust über die Förderlänge massiv ansteigt, und aus dem in oder nahe bei der Fasspresse vorliegenden Druck in dem zu fördernden Material nicht auf den beim Verbraucher anliegenden Druck im Material geschlossen werden kann.
  Entleert man einen solchen Behälter dagegen konventionell, also mittels einer Pumpe, zum Beispiel einer Kolbenpumpe, so besteht das Problem darin, dass in vielen verschiedenen Materialien sehr abrasive Füllstoffe enthalten sind, die bewirken, dass jede Pumpe innerhalb kurzer Zeit verschlissen ist.
• In diesem Zusammenhang besteht ein Problem auch darin, dass der Staudruck in der Förderleitung so hoch werden kann, dass die Dichtung zwischen dem äußeren Rand der Pressplatte und der Innenumfangswand des Fasses von dem Material durchdrungen wird und Material auf die Oberseite der Pressplatte gelangt.

This type of drum emptying has several problems:

• On the one hand, the force required to press down the press plate increases sharply with increasing viscosity, i.e. toughness, of the material to be conveyed, so that relatively tough, highly viscous material can hardly be conveyed over further conveying routes without an additional pump in the emptying device or in the course of the conveying route becomes possible.
• Another problem is that when the press plate is placed on the viscous material under the press plate, air is trapped, which enters the conveying line when the material is conveyed, which is fundamentally undesirable, since the material should often be applied by the consumer in a precisely dosed manner, and this dosage is no longer possible when there are air bubbles in the delivery line. B. generated glue application can be incomplete and thus faulty.

• Furthermore, in order to reduce the necessary pressing force, especially in the case of highly viscous materials, it would be sensible to encourage the flow of the material into the conveying line by a conical design of the pressing plate. However, this leads to a large amount of residue that remains in the barrel towards the end of emptying.
• Furthermore, it must be avoided that the press plate or the drive of the press plate is damaged by the relatively high forces on the press plate if the press plate reaches the bottom of the barrel and the drive is not switched off in time.
• Another problem is that with increasing viscosity of the material, the pressure loss increases massively over the conveying length, and the pressure in the material to be conveyed in or near the drum press cannot be used to determine the pressure in the material at the consumer.
  If, on the other hand, such a container is emptied conventionally, i.e. by means of a pump, for example a piston pump, the problem is that very abrasive fillers are contained in many different materials, which cause every pump to wear out within a short time.
• In this connection, there is also a problem that the back pressure in the delivery line can become so high that the seal between the outer edge of the pressure plate and the inner peripheral wall of the barrel is penetrated by the material and material reaches the top of the press plate.

From the DE 1808241 A1 , which represents the closest prior art, an emptying device for barrels is known, wherein from the back of the press plate of the press cylinder extends in the retraction direction and a check valve with a flow direction from the front to the rear is located in the press plate. The press cylinder is not movable in both directions and the delivery piston, which does not rest with its outer edge on the circumferential wall of the press cylinder, has no through-opening to the rear of which the delivery line could be connected.

III. Presentation of the invention a) Technical task

It is therefore the object of the invention to create an emptying device with a drum press that works reliably even with highly viscous materials and has a sufficient service life, and to provide a method for emptying such highly viscous materials.

b) Solution of the task

With regard to the emptying device, this object is achieved in that the conveying line is not attached directly to the through opening of the press plate.

Instead, extends from the back, usually the top, the press plate from a press cylinder in the retraction direction, which with his front, usually lower, end is tightly connected to the press plate, which thus forms part of its bottom.

Because since this press cylinder moves into the container together with the press plate when the container is emptied, the press cylinder has a free inner diameter that is smaller than the free inner diameter of the container to be emptied, and the outer circumference of the press cylinder is also included positioned a radial distance from the outer edge of the press plate, so set back radially inward.

In the press cylinder, a delivery piston is axially displaceable close to the inner circumference of the press cylinder, just like the press plate itself, both in the conveying direction and in the retraction direction, and is driven by its own conveyor drive, which can be controlled independently of the press drive, which moves the press plate axially .

In the delivery piston, a through opening is arranged, mostly in the center, on the rear side of which the delivery line is tightly fastened, through which the material to be removed can flow.

So that the material from the barrel can reach this through opening in the delivery piston, one or more check valves are provided in the press plate so that the material only penetrates the press plate from the front to the rear, i.e. usually from bottom to top, i.e. in the direction of the delivery piston can, but not the other way around.

The check valves should preferably not protrude beyond the rear of the press plate and / or not beyond its front.

With this arrangement, the following procedure is possible: First, the press plate and delivery piston are brought into their starting position. For the press plate, this means that it is moved into the container through the open end face of the latter and placed on the surface of the material to be removed from it.

For the delivery piston, this means that it is brought into an axial starting position which is usually as close as possible to the rear of the press plate, in that it preferably rests on this rear of the press plate.

1. a) Die Pressplatte wird zusammen mit dem daran befestigten Presszylinder weiter in Pressrichtung in den Behälter, also in Richtung des Bodens des Behälters, eingefahren. Das dadurch im Behälter unter Druck gesetzte Material strömt dementsprechend durch das eine oder die mehreren Rückschlagventile durch die Pressplatte hindurch auf deren Rückseite und beginnt, den Presszylinder zu füllen und dabei den Förderkolben im Presszylinder von seiner Ausgangslage aus in Rückzugsrichtung zurück zu schieben:
   Da der freie innere Durchmesser des Behälters größer ist als der freie innere Durchmesser des Presszylinders, bedeutet ein Vorwärtsschieben der Pressplatte um eine Längeneinheit in Förderrichtung, dass der Förderkolben - um das dadurch verdrängte Material-Volumen aufzunehmen - sich um mehr als diese Längeneinheit von seiner Ausgangslage aus relativ zum Presszylinder in Rückzugsrichtung zurückgeschoben wird.
   Wenn im Presszylinder auf diese Art und Weise ein vorgegebener Füllstand erreicht ist, also der Förderkolben eine vorgegebene axiale Soll-Lage erreicht hat, wird
2. b) die Axialbewegung der Pressplatte angehalten.
3. c) Bei weiterhin angehaltener, also stillstehender, Pressplatte wird nun der Förderkolben in Pressrichtung bewegt, also auf die Pressplatte zu bewegt, bis er eine vorgegebene Ziel-Position erreicht hat, meist anliegend oder unmittelbar benachbarte zur Pressplatte. Da das zwischen Förderkolben und der Rückseite der Pressplatte eingeschlossene Material durch die Rückschlagventile nicht entweichen kann, wird das Material dadurch in die Durchgangsöffnung im Förderkolben und die daran angeschlossene Förderleitung - die anschließend an den Förderkolben in der Regel zunächst aus der hohlen Kolbenstange des Förderkolbens besteht - hineingepresst und damit in Richtung Verbraucher transportiert.

The following process is then carried out - depending on the material requirement more or less quickly, but usually several times in succession - until finally no more material is required or the container is empty:

1. a) The press plate, together with the press cylinder attached to it, is moved further in the pressing direction into the container, that is to say in the direction of the bottom of the container. The material thus pressurized in the container flows accordingly through the one or more check valves through the press plate on its rear side and begins to fill the press cylinder, thereby pushing the delivery piston in the press cylinder back from its starting position in the retraction direction:
   Since the free inner diameter of the container is larger than the free inner diameter of the press cylinder, pushing the press plate forward by a unit of length in the conveying direction means that the conveying piston - in order to take up the volume of material displaced by it - moves more than this unit of length from its starting position is pushed back relative to the press cylinder in the retraction direction.
   When a predetermined fill level is reached in the press cylinder in this way, that is to say the delivery piston has reached a predetermined axial target position, is
2. b) the axial movement of the press plate stopped.
3. c) With the press plate still stopped, i.e. stationary, the delivery piston is now moved in the pressing direction, that is, moved towards the press plate until it has reached a predetermined target position, usually in contact with or directly adjacent to the press plate. Since the material trapped between the delivery piston and the back of the press plate cannot escape through the check valves, the material is thus drawn into the through opening in the delivery piston and the delivery line connected to it - which then comes to the delivery piston, as a rule, initially from the hollow piston rod of the delivery piston - pressed in and thus transported towards the consumer.

This has the advantage that when the material is pressed out of the press cylinder into the delivery line, higher pressures can also be applied than the maximum value permissible for the press plate seal.

The seal between the outer circumference of the delivery piston, which can be precisely matched to one another, and the inner circumference of the press cylinder - which can also be made more stable than a barrel - is, however, generally much more resilient than the seal of the press plate against the interior circumference of the barrel, which is subject to great manufacturing inaccuracies.

In this way, even with very viscous material, reliable conveyance of the material is possible without material being pressed through the seals.

The starting position, the target position and the target position of the delivery piston can of course preferably be adjustable, as can the distance that the press plate takes in each delivery process.

In addition, the pressure in the material is measured to control the process, for example on the front of the press plate and / or on the front of the delivery piston and / or in the delivery line, be it close to the delivery piston and / or close to the consumer.

On the basis of these pressure values and the known parameters of the material to be emptied, the movement of the press plate and / or delivery piston is controlled with regard to the time sequence, duration and speed of these components.

In order to avoid air inclusions in the material to be conveyed, either before and especially when the press plate is placed on the top of the material in the container, the space in between is subjected to negative pressure or the entire container to be emptied is sealed in an enclosure at least with its open side recorded, which is acted upon with negative pressure above all before and when the press plate is placed on the material in the interior in order to reliably avoid air inclusions.

In order to carry out this process, it makes sense to provide further details for the emptying device :
The inner diameter of the press cylinder is by no means as large as possible relative to the inner diameter of the container to be emptied, in particular the barrel, but preferably at least 5%, better at least 10%, better at least 15%, better at least 20%, better at least 30% smaller chosen to keep the circumferential length of the seal between the delivery piston and press cylinder as small as possible.

The press plate drive and the conveyor plate drive can be controlled independently of one another and preferably contain one or two parallel threaded spindles as a drive element or a working cylinder, for example a hydraulic cylinder or a pneumatic cylinder.

Simple ball valves or other forms of check valves can be provided as check valves. Preferably, however, the check valves should not protrude beyond the back of the press plate - otherwise the delivery piston could not be moved all the way to the back of the press plate - and / or not protrude over the front of the press plate - otherwise the front of the press plate would not completely touch the Bottom of the barrel could be approached.

Therefore, the pressure plate should preferably have such a thickness in the axial direction that the one or more check valves have full space in it in the axial direction.

In order to ensure a quick passage of the material through the press plate in the direction of the delivery piston, the sum of the free passages of the total check valves - which may only be located in the radial area within the free diameter of the press cylinder - should be at least 15% in their open state, better at least 20%, better at least 30%, better at least 40%, better at least 50% of the bottom surface of the press cylinder.

In order to avoid a leakage problem between the press plate and the adjoining press cylinder, the safest solution is to make the press plate in one piece with the press cylinder, which, however, requires a lot of manufacturing effort and is usually only chosen for extremely thin-bodied materials.

In contrast, the press plate is preferably fastened to the press cylinder in a simple manner so that it can be detached, that is, it can be both dismantled and assembled.

This has several advantages:
On the one hand, the press plate can be removed from the press cylinder for cleaning purposes.

Above all, however, in this way, adapted to the diameter of the drum to be emptied, a corresponding press plate can be attached to the press cylinder so that the emptying device can be used for drums of different diameters.

To control the method , pressure sensors are used on the one hand, in particular at the aforementioned points, and on the other hand position sensors that are present either on the press plate and / or on the delivery piston, and with which the axial position on the one hand of the press plate within the emptying device, i.e. when in use relative to the barrel, and on the other hand the axial position of the delivery piston relative to the press cylinder.

In order to intensify the conveyance of the material, a peristaltic pump which acts on the hose from the outside is preferably provided in the conveying line, which consists at least in sections of a flexible hose.

In order to avoid air inclusions in the conveyed material, a vacuum connection can be provided in the front of the press plate - radially away from the area of the press cylinder - and / or in the conveying line.

Another possibility to avoid air inclusions in the conveyed material is that the frame of the emptying device also comprises a housing into which either the entire container or at least the part of it containing the open side of the container is placed and at least the open side is tightly closed can be. The housing has a vacuum connection via which the interior of the housing can be connected to a vacuum source.

In order to minimize the pressure increase due to friction of the material on the inside of the delivery line, the inner surface of the delivery line can have a friction-reducing surface design.

Since there is no continuous conveyance of the material through the conveying piston in the described method, a buffer for material is preferably present in the conveying line in order to be connected to the material from the buffer even when the conveying piston is stationary in the press cylinder To continue to supply consumers with material from the buffer.

Such a buffer in the delivery line can for example be a piston pump or a diaphragm pump with a sufficiently large volume.

As a rule, the piston rod of the delivery piston, and possibly even the press cylinder, will then have to extend through the housing.

c) Embodiments

Embodiments according to the invention are described in more detail below by way of example.

Fig. 1a:

in der Frontansicht,

Fig. 1b:

in der Seitenansicht,

Fig. 1c:

in der Aufsicht von oben,

Fig. 2:

im Vertikalschnitt in Blickrichtung von vorne und

Show a barrel press according to the prior art with the vacuum container open

Fig. 1a:

in the front view,

Fig. 1b:

in the side view,

Fig. 1c:

in the supervision from above,

Fig. 2:

in vertical section looking from the front and

Figur 3:

im gleichen Vertikalschnitt wie Figur 2,

Figuren 4a bis e:

in unterschiedlichen Funktionsstellungen der Fasspresse gemäß der Figur 3

Show a barrel press according to the invention

Figure 3:

in the same vertical section as Figure 2 ,

Figures 4a to e:

in different functional positions of the barrel press according to Figure 3

The Figures 1a , b, c and 2 show an emptying device in the form of a barrel press in external views and in sectional views:
Material 52 should be made from the Figures 1a and 2 shown, open-topped, barrel 50 are promoted by the press plate 2 , which is in the inner circumference of the barrel 50 can be pushed in tightly from above, and exerts pressure on the material 52 with its pressure side 2a , so that this - as best shown in FIG Fig. 2 to be seen - is then pushed upwards by the hollow piston rod 17 protruding from the opposite rear side 2b and through the feed line 4 connected to it to the only in the Fig. 2 indicated consumer 53 is pushed.

Since this process should take place under negative pressure, ideally under vacuum, the barrel 50 is first set in a housing 6 , which consists of a solid housing 6 a and the door 6 b shown here in the pivoted state, which in the closed state Housing 6 seals, in the interior 9 of which the desired negative pressure is generated. For this purpose, the housing 6 has a vacuum connection 7 , via which the housing 6 is connected to a vacuum source 8 .

The only element extending through the top of the housing 6 into the interior 9 is the piston rod 17, at the front end of which the pressure plate 2 is attached and which moves the pressure plate 2 , the passage being sealed accordingly to prevent air from outside into the to let penetrate under pressure interior 9 .

Since very high forces of up to 100 tons have to be applied to the press plate 2 or the piston rod 17 driving it with highly viscous materials, the housing 6 is located in a solid frame 1 , in the upper area of which there are two vertically arranged parallel lines next to each other Threaded spindles 15 or ball screw spindles are arranged, which act together on a transverse yoke 12 , which is connected to the rear, upper end of the hollow piston rod 17 , which extends up to the pressure plate 2 .

So that the drum 50 is not radially deformed or even bursts by the pressure exerted on the material 52 in the drum 50 by means of the press plate 2, a stable enclosure is usually provided around the drum 50 in the prior art 13 - see Figure 1a - Attached, which rests closely on the outer sides of the barrel 50 and withstands the pressure therein.

Nevertheless, in this case, too, the press plate seal is not completely tight due to the deformation of the barrel, and in addition such a stable enclosure 13 not only creates an expense in the manufacture of the machine, but also, depending on the dimensions of the barrel 50 , mostly for the barrels from different manufacturers, a separate matching enclosure 13 is required.

Even when a new barrel 50 is placed in an enclosure with such a stable enclosure for the barrel, this makes the setting process of each barrel cumbersome and prone to errors.

Another disadvantage is the fact that barrels have a relatively large range of fluctuation in their actual dimensions, especially with regard to wall thickness, inner diameter and outer diameter.

According to the invention , therefore, a design of the emptying device according to Fig. 3 suggested having the same view as Fig. 2 used:
It can be seen that a press cylinder 22 extends from the rear side 2b of the press plate 2 upwards, i.e. in the retraction direction 10b of the axial direction 10, and in the cross section of the press plate 2 within the inner circumference of this press cylinder 22 for the material 52 to be conveyed at least one, usually several, through-openings 3 are present, which are now each designed as check valves 19 , in this case with a ball 19a as the valve body. The flow direction of this at least one check valve 19 is exclusively the direction from bottom to top, that is to say into the interior of the press cylinder 22 , and not vice versa.

The pressing plate 2 is about usually several in the axial direction 10 consecutively arranged press plate seals 14 on the inner circumference of the wall 50b of the barrel 50 slidably mounted.

The press cylinder 22 is hollow in the axial direction 10 and a press piston 24 is guided in it so that it can be moved in the axial direction, sealed by a plurality of delivery piston seals 23 arranged one behind the other in the axial direction .

The delivery piston 24 has a central through-opening 3 ' which opens into the axially hollow piston rod 17 extending upwards from the plunger 24 , i.e. in the retraction direction 10b, to which the delivery line 4 is connected in its upper, downstream end area leads to consumer 53 .

The pressing plate 2 on the one hand and the delivery piston 24 on the other hand can be moved independently of one another in the axial direction 10 both in the pressing direction 10a and in the retraction direction 10b.

The positions of the delivery piston 24 and the press plate 2 can be monitored by one or a common position sensor 55 , one of which is shown in FIG Figure 3 one is arranged on the housing 6 next to the through opening for the piston rod 17 and the other on the piston rod 17. A pressure sensor 54 can also be present, for example in the underside of the delivery piston 24 , to measure the pressure in the material 52 below.

The movement takes place either by means of a common drive 5 , but nevertheless independently of one another insofar as either the press cylinder 22 , i.e. the piston rod of the press plate 2, or the piston rod 17 of the delivery piston 24 or both can be coupled simultaneously with this common drive 5 .

The press cylinder 22 is slidably sealed in the axial direction in the passage in the upper side of the housing 6 , as was also the case in the solution according to the prior art with the piston rod 17 of the press plate 2 .

Of course, it is also possible to drive the press plate 2 on the one hand and the delivery piston 24 on the other hand in the axial direction by means of separate drives, i.e. to couple a drive on the one hand to the press cylinder 22 and on the other hand to the piston rod 17 .

With this embodiment of the emptying, it is possible to introduce the pressing plate 2 in the open upwardly facing side of the barrel 50, to set up and on the to be removed material 52 by further downward drive of the pressing plate 2, the material 52 through the through-holes 3 of the die 2 - the permeability direction 19 'of the check valves 19 - in the area above the press plate 2 and thus into the press cylinder 22 to flow. The prerequisite for this is that the delivery piston 24 does not offer any great resistance when it is reached by the material 52 , but only the sliding friction between the delivery piston seal 23 and the press cylinder 22 and the weight of the delivery piston 24 and its piston rod 17 have to be overcome .

In the case of a common drive of the press plate 2 and delivery piston 24 , when the press plate 2 is pressed down by means of the common drive 5, the delivery piston 24 must not be coupled to this drive but be freely movable with respect to this drive.

In contrast, in order to press the material through the piston rod 17 and the connected delivery line 4 to the consumer, a considerably higher pressure is necessary. This is applied by ending the forward movement, that is to say downward movement, of the press plate 2 after the interior of the press cylinder 22 has been sufficiently filled with material 52 and with the press plate 2 stationary, the delivery piston 24 is pressed downwards. In the case of a common drive 5 , this means that for this purpose the press plate 2 must be decoupled from the drive 5 and instead the delivery piston 24 must be connected directly to it.

The necessary high pressure now only occurs between the upwardly facing back of the press plate 2 including the check valves 19 - which are not permeable to the material 52 in the direction from top to bottom - and the delivery piston 24 and thus also in the piston rod 17 , but not in the area between the bottom 50a of the barrel 50 and the press plate 2. This high pressure does not act on the press plate seal 14 between the press plate 2 and barrel 50 , the sealing effect of which can therefore be significantly less than that of the delivery piston seal 23.

Furthermore, the pressure generated between the press plate 2 and the delivery piston 24 - when the same force is applied as in the known solution according to FIG Fig. 1 and 2 - Significantly higher because of the smaller cross-sectional area of the delivery piston 24 compared to the cross-sectional area of the press plate 2 , as is relevant in the known solution. This means that in the solution according to the invention, a weaker drive 5 is sufficient to generate the same pressure.

In this way, a barrel can now be emptied in one or usually several steps, as with the Figure 4a - e recognizable:
In the first step according to Figure 4a the press plate 2 is moved into the barrel 50, placed on the surface of the material 52 located therein, and moved down until there is a sufficient amount of material in the press cylinder 22 below the delivery piston 24 , which has either been pushed up or is was already in a raised position relative to the press plate 2 .

Connect according to Figure 4b stopping the press plate 2 and as far as possible and ultimately pressed by moving down, thus moving in the forward direction of the delivery piston 24 disposed between the stationary die 2, and located the delivery piston 24 material in the piston rod 17 into the conveying conduit 4 and to the consumer 53rd The forward movement of the delivery piston 24 ends at the latest when the rear side 2b, that is to say the upper side, comes into contact with the press plate 2.

This process can be performed according to the Figures 4c and d can be repeated one or more times.

In a final emptying step, the press plate 2 is then moved down until it rests on the bottom 50a of the barrel 50 , then stopped and the delivery piston 24 lowered until it rests on the rear 2b, the top, of the press plate 2 .

The barrel is thus emptied, the pressing plate 2 can be moved upwards out of the barrel 50 and the empty barrel 50 can be exchanged for a full one.

Both in the prior art and in the solution according to the invention, a spindle nut 25 , through which the threaded spindle 15 extends, can be fixedly mounted in the frame 1 . Each of the two threaded spindles 25 is in the present case driven by a separate electric motor 16 , the rotations of the two spindle nuts 25 , which cause the axial movement of the threaded spindles 15 , are mechanically synchronized by a synchronous connection that acts between the two spindle nuts 25 and is operatively connected to both, in particular in form a clutch.

In order to know the relative position of the pressing plate 2 in the feed direction on the frame, a position sensor 21 is disposed, consisting for example of a sensor bar 21 a which is fixed to the inside of the frame 1 and a position transmitter, for example a position magnet 21 b, in the case of a magnetostrictive sensor, which moves in the vertical, i.e. axial, direction when the unit of threaded spindles 15 , yoke 12 , piston rod 17 and pressure plate 2 moves downwards along the sensor strip 21 a and thus the position of the press plate 2 is detected so that the press plate 2 can be stopped when it has reached the bottom of the barrel 50 and this is thus emptied.

The conveying line 4 conveying away the material is attached to a corresponding connection piece of the yoke 12 , so that the conveying line 4 usually consists of a flexible but high-strength hose that is led away from the rear of the frame 1 , as in the Figures 1b and 2 shown.

REFERENCE LIST

1

frame

2

Press plate

2a

Print side

2 B

back

3, 3 '

Through opening

4th

Delivery line

5

drive

6

Enclosure

6a

casing

6b

door

7th

Vacuum connection

8th

Negative pressure source

9

inner space

10

axial direction, vertical

10a

Pressing direction

10b

Withdrawal direction

11

Cross direction, horizontal

12

yoke

13th

Embracing

14th

Press plate seal

15th

Threaded spindle

16

Electric motor

17th

Piston rod

18th

Spring package, energy storage

19th

check valve

19 '

Direction of permeability

19a

Bullet

20th

control

21a, b

Position sensor

22nd

Press cylinder

23

Delivery piston seal

24

Delivery piston

25th

Spindle nut

26th

coupling

50

barrel

50 a

ground

50b

Perimeter wall

52

material

53

consumer

54

Pressure sensor

55

Position sensor

Claims (14)

1. Emptying device for supplying a consumer (53) with viscous material (52) from a container (50) having an open side (50a) and a peripheral wall (50b) running in the axial direction (10), in particular a barrel (50), the emptying device comprising

   - a frame (1) for receiving the container (50),

   - a movable press plate (2), which

   - can be driven both in the press direction (10a) and in the withdrawal direction (10b) by a press plate drive (5),

   - fits into the container (50) from the open side and, thereby same time, bears closely with its outer edge against the inner surface of the peripheral wall (50b) of the container (50),

   - a conveyer line (4), connected to a through opening (3) of the press plate (2), for the material (52) to be conveyed away,
   characterised in that

   - a press cylinder (22) extends from the rear side of the press plate (2) in the retraction direction (10b),

   - at least one non-return valve (19) with a passage direction (19') from the front side (2a) to the rear side (2b) of the press plate (2) is located in the radial region within the press cylinder in the press plate (2),

   - a conveying piston (24) which can be moved both in the press direction (10a) and in the withdrawal direction (10b) by a conveying drive (5') is present in the press cylinder,

   - the outer edge of the conveying piston (24) lies closely against the inner surface of the peripheral wall (50b) of the press cylinder (22),

   - the conveying piston (24) has a through opening (3') to the rear of which the conveyer line (4) is connected.
2. Emptying device according to claim 1,
   characterised in that

   - the inner diameter of the press cylinder (22) is smaller than the free inner diameter of the peripheral wall (50b) of the container (50) and

   - in particular the inner diameter of the press cylinder (22) is at least 5 %, better at least 10 %, better at least 15 %, better at least 20 %, better at least 30 % smaller than the free inner diameter of the peripheral wall (50b) of the container (50).
3. Emptying device according to one of the preceding claims,
   characterised in that
   the press plate drive (5) and/or the conveyor drive (5'), which may also be functionally combined to a single drive, comprise one or two threaded spindles running in parallel or a working cylinder, in particular a hydraulic cylinder or a pneumatic cylinder.
4. Emptying device according to one of the preceding claims,
   characterised in that

   - the at least one non-return valve (19) is a ball valve
   and/or

   - the sum of the free passages of the non-return valves (19) present in their open state is at least 15 %, better at least 20 %, better at least 30 %, better at least 40 %, better at least 50 % of the bottom area of the compression cylinder (22).
5. Emptying device according to one of the preceding claims,
   characterised in that

   - the press plate (2) is made in one piece with the press cylinder (22)
   and/or

   - the press plate (2) is fastened to the press cylinder (22) in a dismountable and mountable manner.
6. Emptying device according to one of the preceding claims,
   characterised in that

   - at least one pressure sensor (54) is present at the conveying piston (24) and/or close to the consumer, which pressure sensor measures the pressure in the material (52),
   and/or

   - at least one position sensor (55) is present at the press plate (2) and/or at the conveying piston (24), which sensor either measures the axial position of the press plate (2) in the emptying device or measures the axial position of the conveying piston (24) in the press cylinder (22).
7. Emptying device according to one of the preceding claims,
   characterised in that

   - the conveyer line (4) consists at least in sections of a flexible hose and a hose pump acting on the hose from the outside is arranged at the flexible hose,
   and/or

   - a vacuum connection (7) is present in the front side (2a) of the press plate (2) radially away from the press cylinder (22) and/or in the conveyer line (4) at or near the consumer,
   and/or

   - the inner surface of the conveyer line (4) has a friction-reducing surface.
8. Emptying device according to one of the preceding claims,
   characterised in that

   - a buffer for material (52) is present in the conveyer line (4), in particular in the form of a piston pump or a diaphragm pump, having a sufficiently large volume in order to be able to continue to supply the consumer with material (52) from the buffer in case of a standstill of the emptying of the container (50).
9. Emptying device according to one of the preceding claims,
   characterised in that

   - the frame (1) comprises an enclosure (6) which can be tightly closed and/or opened for introducing at least the part of the container with the open side or for introducing the entire container (50),

   - the enclosure (6) has a vacuum connection (7) via which the internal space (9) of the enclosure (6) can be connected to a vacuum source (8),

   - the piston rod (17) of the conveying piston (24) and the press cylinder (22) extend through the wall of the enclosure (6).
10. Method for emptying viscous material (52) from a container (50) which is open on one side, in particular a barrel (50), by means of an emptying device according to one of the preceding claims, in that

    - the press plate (2) is placed on the surface of the material (52) in the container (50), wherein the conveying piston has an axial starting position relative to the press plate (2) and in this case touches in particular the rear side (2b) of the press plate (2), and then

    a) the pressing plate (2) is further moved into the container (50) in the conveying direction (10a) until the material (52) passing through the at least one non-return valve has filled the press cylinder to a predetermined filling level and has thereby in particular pushed the conveying piston in the press cylinder rear side in the withdrawal direction (10b),

    b) the press plate (2) is stopped,

    c) with the press plate (2) stationary, the conveying piston is moved further into the press cylinder in the conveying direction (10a) until it has reached a predetermined target position relative to the press plate (2).
11. Method according to claim 10,
    characterised in that
    steps a) to c) are repeated several times in succession, in particular until the pressing plate (2) has reached the bottom of the container (50).
12. Method according to one of the preceding method claims,
    characterised in that
    the starting position and/or the target position of the conveying piston (24) are adjustable.
13. Method according to one of the preceding method claims,
    characterised in that
    the pressure in the material (52) is measured on the front side (2a) of the pressing plate (2) and/or on the front side of the conveying piston and/or in the conveyer line (4) close to the consumer and is reported to a controller and, depending thereon, the press plate drive (5) and/or the conveying piston drive (5') is controlled by a controller, in particular taking into account the time delay of the pressure progress along the conveyer line (4).
14. Method according to one of the preceding method claims,
    characterised in that

    - before and during placing the press plate (2) on the upper side of the material (52) in the container (50), the space between is pressurised with negative pressure,

    - in particular in that the container (50) open on one side is completely or at least with its open side introduced into an enclosure (6),

    - the enclosure (6) is tightly closed and then the internal space (9) of the enclosure (6) is pressurised with negative pressure.

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