EP3812583A1 - Pump unit, storage device equipped with the same and method for operating the storage device - Google Patents

Abstract

In order to make the two pump units (1), which are present in an emptying device for a storage container (101), alternately conveying on the one hand as inexpensive as possible and on the other hand with little wear and tear, both pump units (1) are equipped with a feed pump (1.1) in Equipped in the form of a diaphragm pump which is driven by a working cylinder unit (1.2); which is operated pneumatically in particular. Regardless of the type of drive of the feed pump (1.1), the axial position of the drive plunger (9) for the membrane (4) or the membrane (4) is constantly detected and the pump unit (1) is detected via this controlled.

Description

I. Field of application

The invention relates to a pump unit for transporting liquid and, above all, viscous substances such as adhesives and resins, as well as a storage device which comprises a storage container for such materials, from which these materials are pumped to a downstream consumer by means of such a pump have to.

II. Technical background

Pasty materials in particular, e.g. casting compounds to encapsulate electronic circuits in a moisture-proof manner or adhesives to connect components tightly to one another, are often applied to the relevant components in the industry by means of appropriate, automated application processes using automatic dispensing machines, and must accordingly be constantly applied to the relevant components Material are supplied.

For this purpose, such a consumer is connected via lines to a storage device in which the corresponding material is located in a mostly pot-shaped storage container. In the line that leads from a mostly deep removal opening of this storage container to Consumer leads, a pump unit is arranged, which causes the transport of this viscous material.

One problem is that these materials often contain abrasive solids in finely divided form, which is why certain pump designs, such as continuously operating screw pumps, cannot be considered.

Instead, piston pumps are often used which, even with abrasive material to be conveyed, wear less quickly and can also be manufactured more cost-effectively, but do not offer a continuous flow rate.

For this reason, two non-continuously delivering feed pumps, especially in the form of piston pumps, are operated in parallel, which are usually connected to the same storage container via separate connections and which are controlled in such a way that one piston pump just completes a working stroke, i.e. material in Ejects towards the consumer, while the other piston pump is currently completing a return stroke, i.e. its pump chamber is currently being filled with new material from the storage container.

Nevertheless, depending on the material to be conveyed, piston pumps also wear out during such use and have to be replaced from time to time, which on the one hand results in system downtimes and, of course, on the other hand, the costs for repair and assembly of the pump.

However, a very precise volume to be maintained with each pump stroke is not necessarily a prerequisite for transporting to the container, because there only has to be a sufficient, preferably always, in the supply line to the consumer and thus in the outlet opening of the feed pump constant pressure is present so that the consumer is always adequately supplied with material:
This material pressure, which is present when the consumer is not removing any material, i.e. when the outlet opening is virtually closed, can collapse when the consumer removes material from the pump unit, especially if this happens relatively quickly. However, the supply pressure present there when the consumer is inactive should not drop to zero, which is why - in particular depending on the consumer - the material pressure at the outlet opening when the consumer is inactive should be a predetermined setpoint pressure pset.

As soon as this removal has ended, the material pressure at the outlet opening of the pump unit, in particular the feed pump, and thus the supply pressure of the consumer, will rise again.

• ein zusätzliches Rührwerk aufweisen, um das Sedimentieren schwererer Inhaltsstoffe zu verhindern,
  und/oder
• eine Heizung aufweisen, um das viskose Material durch Temperaturerhöhung dünnflüssiger zu machen,
  und/oder
• vor allem eine Entgasungseinheit aufweisen, um eventuell in dem Material noch vorhandene Lufteinschlüsse zu beseitigen, bevor das Material zum Verbraucher gepumpt wird.

Since it is often sensitive to their handling and storage materials, such storage containers

• have an additional agitator to prevent the sedimentation of heavier ingredients,
  and or
• have a heater to make the viscous material thinner by increasing the temperature,
  and or
• in particular have a degassing unit in order to remove any air inclusions that may still be present in the material before the material is pumped to the consumer.

III. Presentation of the invention a) Technical task

It is therefore the object of the invention to provide a pump unit - especially for the bearing device described - that is simple and inexpensive to manufacture, is subject to the least possible wear, and enables a constant delivery pressure with little structural effort, including materials can cope with abrasive ingredients and which can also be quickly and easily replaced if necessary.

Furthermore, it is the object of the invention to provide a method for operating such a pump unit which enables a defined, constant pressure at the outlet opening of the pump unit with little effort.

b) Solution of the task

This object is achieved by the features of claims 1, 10 and 12. Advantageous embodiments emerge from the subclaims.

Like every pump unit , a generic pump unit for pasty material also comprises a feed pump, which has a pump element that can be moved relative to the feed pump housing, and a feed pump drive for this feed pump.

According to the invention, the wear of the conveyor pump due to the material to be conveyed is reduced in that the pump element comprises at least one elastic element, preferably the elastic element itself is the pump element.

The elastic element is arranged in such a way that it is only in contact with the material to be conveyed on one side during pumping operation, and thus divides the space inside the feed pump housing into a conveying space in which the material to be conveyed is located, and a drive space through which the feed pump drive extends and in which there is no material to be conveyed.

Since the material to be conveyed cannot get between the elastic element on the one hand and other elements moving along the surface of the elastic element on the other hand, only little wear will occur, in particular caused by the abrasive properties of the material.

Such a pump unit preferably also comprises a controller, as a rule an electronic controller, which controls at least all movable components of the pump unit.

There are different types of pumps that include an elastic element as part of the pump element:
On the one hand, a bellows pump in which a pump piston is axially movable in a pump housing, but the pump piston does not lie tightly against the cylinder wall with its outer circumference - be it via seals or piston rings - and moves along it , but ends radially at a distance from the inner circumferential wall of the cylinder, whereby a sleeve-shaped, elastic bellows, usually a bellows, is tightly fastened with its one annular end edge on the outer circumference of the pump piston and with its other annular end edge on the pump housing.

Another design is a so-called diaphragm pump, in which an elastic, approximately plate-shaped diaphragm covers the interior of the pump housing - usually formed by two bell-shaped or cup-shaped housing parts, which are fastened tightly against each other with the open sides - the interior space in the pump housing is divided into a pumping chamber and a working chamber, and is fastened on its outer edge tightly against the pump housing, for example between the two screwed against each other Housing halves is tightly attached.

By moving the membrane transversely to its main plane, the conveying space is alternately enlarged and reduced, so that the material contained therein is pressed out through an outlet opening by means of corresponding inlet and outlet valves by means of the membrane from the conveying space filled with the material at maximum volume when its volume is reduced and is conveyed to the consumer and is filled with material when increasing its volume through the inlet opening.

The construction as a diaphragm pump, which is in the foreground of the present invention, is very simple and inexpensive to manufacture, since the individual components for this are inexpensive to manufacture due to only a few and also flat fitting surfaces, in contrast to a piston pump.

While the inlet valve is preferably an active, i.e. drivable and in particular controllably drivable, valve which, however, preferably only needs to be movable back and forth between the fully open and fully closed position, the outlet valve can be a simple, passive, i.e. not driven by a valve drive Be an outlet valve, for example in the form of a check valve. It will only be an active valve that can be driven in a controlled manner in special cases.

The outlet valve prevents material already in the outlet line from being returned to the pumping chamber of the diaphragm pump during the filling stroke arrives, in which, by increasing its volume, material is to pass through the inlet opening, in particular from the storage container to be emptied, and this is to be filled.

The non-return valve can be arranged with the larger side of its passage facing upwards and only assume the closed position by the weight of the valve element, usually a ball, and / or additionally be biased into the closed position by means of the force of a spring the effort for the manufacture of the required valves, especially the exhaust valve, is very low.

If, however, two pumps that do not deliver continuously, such as two diaphragm pumps, are operated alternately in parallel in order to achieve a flow to the consumer that is as constant as possible, the outlet valves are preferably controlled valves in order to be able to precisely control the open and closed intervals of the two outlet valves with respect to one another.

Such a pump can be driven in different ways:
A first possibility is to alternately apply negative pressure or positive pressure of a drive medium, for example air, directly to the drive space of the feed pump.

For this, however, a high pressure of the drive medium is required, and it is difficult to achieve reproducible delivery strokes.

The preferred second option is the feed pump, in the case of the diaphragm pump design the diaphragm of the pump, via a drive tappet whose front end is in operative connection with the side of the diaphragm facing away from the material to be conveyed, i.e. usually in the drive chamber. in particular attached to this, driven transversely to its main plane. The rear end of the drive tappet, on the other hand, is in operative connection with the pump drive or the drive tappet is part of the pump drive.

In the case of a bellows pump, the delivery piston is driven by the drive tappet.

The main plane of the elastic element, in particular a membrane, is understood to mean the plane defined by the annular restraint of this elastic element, in the case of a bellows one of these two planes, which, however, are generally parallel to one another.

The drive tappet and thus, for example, the diaphragm of the feed pump can be set in motion by different drives, be it an electric motor, an eccentric drive, another diaphragm pump or - preferred according to the invention - the piston of a working cylinder, which is preferably operated pneumatically.

The position of the feed pump drive, in particular the drive tappet, is monitored by a position sensor, at least the reaching of its end positions. The position of the feed pump drive, in particular the drive tappet, is preferably detected over the entire movement path.

If the feed pump drive is a working cylinder unit, a distance sensor can be used as the position sensor, which is usually arranged on the rear side of the drive plunger facing away from the pump element, usually the membrane, which in this case is also the piston or the piston rod of the The working cylinder is, and the distance from the distance sensor, which is usually fixedly mounted in the cylinder, to this rear side measures.

The same thing, that is to say a measurement of the axial distance from a distance sensor mounted in a stationary manner, preferably in the working space, can instead or in addition also be provided for the position of the diaphragm of the feed pump.

Alternatively, the lateral surface of the piston could run obliquely to the axial direction of the piston, at least in one area of the circumference, and a distance sensor arranged stationary in the wall of the cylinder could measure the radial distance to this incline, which changes depending on the axial position of the piston . For this, however, the movement path of the piston must not be greater than its axial extent.

Instead or in addition, the same can also be provided for the position of the diaphragm of the feed pump.

The contact surface of the drive plunger, in particular the piston rod of the working cylinder, to the diaphragm is not small and quasi punctiform, viewed in the direction of movement, but rather disc-shaped or ring-shaped with a considerable extent of up to 5%, better up to 10%, better up to to 20%, better up to 25% of the effective surface area of the membrane, that is to say that the material comes into contact during operation, and is preferably arranged centrally. However, the contact area should not be greater than 80%, better not greater than 70%, better not greater than 60%, better not greater than 50%, better not greater than 40% of the effective area of the membrane.

This avoids punctual overloading of the membrane when it is applied.

The membrane preferably has a main part of the membrane in addition to the continuous main part of the membrane that separates the interior space in the pump housing Concentric, ring-shaped membrane extension on the drive side of the membrane, in particular formed in one piece therewith. The annular membrane extension merges with its radially outer edge into the continuous part of the membrane and protrudes from this with its free, radially inner edge and is designed to be resilient in the direction of movement with respect to the continuous main part of the membrane.

The membrane extension is preferably arranged in a ring-shaped circumferential manner between the outer edge and the central region of the main part of the membrane.

A mushroom-shaped membrane support is located as a tension plate with the outer peripheral edge area of its head in the space between the continuous and the annular part of the membrane, and the stem of the mushroom shape extends through the central opening of the annular extension away from the membrane and is releasably connected to the piston rod or directly to the piston of the cylinder, for example screwed.

This means that the membrane can not only be pushed but also pulled. The head of the membrane carrier either sits only in a form-fitting manner between the two parts of the membrane or is firmly connected to one or both of these parts, for example glued.

The continuous main part of the membrane, viewed in a radial section, is preferably designed in such a way that in the unloaded initial state in the central, middle area, in particular in the area of the contact surface, there is a bulge towards the conveying space and / or in the radially outer edge of the membrane, in particular radially away from the contact surface, there is an annular bulge in the direction of the drive space.

This annular bulge is increasingly smoothed and tightened as the diaphragm approaches the feed pump housing and enables the necessary radial length compensation of the diaphragm during operation.

The drive working cylinder is preferably operated pneumatically and therefore has a connection both in its drive space and in its coupling space, i.e. on both sides of the piston of the working cylinder, via which a drive medium, usually compressed air, is used to operate the working cylinder controlled both in the drive space and in the coupling space.

The effective area of the piston of the working cylinder that can be acted upon is preferably greater than the effective area of the diaphragm by at least a factor of 1.4, better by a factor of 1.6, better by a factor of 1.8, better by a factor of 2.0 Diaphragm feed pump.

As a result, even low pressures of the drive medium, mostly air, are sufficient to operate the then pneumatic drive working cylinder.

In addition, the drive space of the feed pump can have a vacuum connection and can be subjected to negative pressure, preferably with the same negative pressure as usually prevails in the storage container to be emptied.

This ensures that the membrane can be actively moved into the fully retracted filling position during the return stroke, and the membrane is not sucked in the direction of the inlet opening by a pressure difference prevailing there in the area of the inlet opening.

A heating device, in particular in the form of electrical heating coils for a heated liquid heating medium or electrical lines, can also be provided upstream of the feed pump housing or in the feed pump housing in order to heat the material to be pumped and thus become more fluid and pumpable to let. Conversely, a cooling device may also be necessary in individual applications, which may include pipelines for a cooled liquid cooling medium.

A liquid sensor is preferably arranged in the drive space of the feed pump, which detects material entering the drive space in the event of a leak, such as a rupture of the membrane, and reports it to the controller, which then emits at least one alarm signal.

In the pumping chamber of the pump or in its ports, at least one pressure sensor may be present at all times to know the pressure conditions in the pump and in particular in the delivery room. As a result, an associated control can react to this, either by changing the pre-pressure of the drive medium or, if necessary, by emitting an alarm signal if the measured pressure exceeds a limit value or a minimum pressure is not reached.

However, there is preferably no pressure sensor in the conveying space, above all in order to keep the number of components susceptible to wear low

With regard to the storage device, in addition to the storage container for the material to be conveyed, at least one of the pump units described above comprises, this object is achieved in that the pump unit is designed according to one of the preceding claims.

The storage device preferably comprises two such pump units, which can be driven in opposite synchronism in order to ensure a quasi-continuous conveyance of the material into the common outlet line to the consumer.

Preferably, however, the two pump units can be controlled independently of one another, so that temporal overlaps of the return stroke of one pump unit and the working stroke of the other pump unit or a time interval between them can also be achieved.

The feed pump, in particular the diaphragm feed pump, is preferably arranged on the storage device in such a way that its inlet valve is located below the outlet opening of the storage container, so that when the inlet valve is open, the material flows into the pumping chamber of the diaphragm pump solely due to gravity.

The main plane of the diaphragm of the diaphragm feed pump can be inclined at an angle of at most 40 °, better at most 30 °, better at most 20 °, better at most 10 ° to the vertical, while the reservoir preferably stands vertically with its open side up stands in the storage device. This results in a particularly space-saving arrangement and thus a compact storage device.

However, the diaphragm feed pump is arranged horizontally with the main plane of its diaphragm in the bearing device.

The feed pump drive of the one or two feed pumps is preferably on the one with respect to the feed pump from the storage container arranged away from the side, so that the pump drive, in particular the drive working cylinder, is easily accessible for repairs.

The tightly closed storage container is preferably subjected to negative pressure in order to prevent air from mixing into the material in the storage container, in particular if the latter is equipped with a mixer.

The air space of the storage container is then preferably connected to the drive space of the feed pump, and this connection can optionally be opened and closed via a valve.

As a result, the same pressure prevails on both sides of the diaphragm in the feed pump, so that when the feed pump is filled, the diaphragm is brought into the optimally close end position to the housing on the drive side and a maximum pump volume is achieved.

• des Antriebs-Stössels
  und/oder
• des den Antriebs-Stössels antreibenden Förderpumpen-Antriebes
  und/oder
• der Membran, insbesondere eines definierten Punktes oder Bereiches der Membran,

direkt oder indirekt ermittelt wird und abhängig davon der Druck des Antriebsmediums, meist Druckluft, mit dem die ihn antreibende Arbeitszylinder-Einheit beaufschlagt wird, gesteuert wird.With regard to the method for operating such a pump unit, in particular in such a storage device, the existing object is achieved in that the axial position of a monitored element, namely

• of the drive tappet
  and or
• of the feed pump drive that drives the drive tappet
  and or
• the membrane, in particular a defined point or area of the membrane,

is determined directly or indirectly and, depending on this, the pressure of the drive medium, usually compressed air, with which the working cylinder unit driving it is acted upon, is controlled.

This is necessary because, depending on the current axial position of the membrane, the change in volume in the delivery space is different for each axial distance covered by the delivery pump drive and thus the drive plunger.

The pump unit therefore does not have a constant transmission ratio between the drive pressure and the material pressure in the delivery space, in particular near its outlet opening, over the path of the feed pump drive and thus the membrane.

Therefore, depending on the respective axial position of the drive tappet or, alternatively, the diaphragm, which is axially fixedly coupled to it anyway, at least in the mutual connection area, a different drive pressure or a different drive force must be present on the feed pump drive in order to maintain a constant, especially with regard to the Set height to provide material pressure in the conveying space, in particular near its outlet opening.

The axial position of the monitored element is determined over its entire movement path - continuously or in steps - and the control of the pump unit uses this position signal to set the drive pressure as a function of this, which is based on the Figures 4a - d will be explained.

If two or more pump units are present, the ejection movement of the drive ram of one pump unit is started before the delivery movement of the drive plunger of the other pump unit has ended in order to continuously offer the connected consumer material with the same material pressure.

The drive chamber of the diaphragm feed pump can also have negative pressure applied to it, in particular with the same negative pressure as the air space of the storage container, in particular as soon as the ejection movement of the drive plunger has ended or permanently to prevent deformations of the Avoid diaphragm in the direction of the material inlet opening.

In order to prevent material from flowing back into the inlet opening during the delivery stroke, the inlet valve is closed as soon as the position sensor reports that the drive key has reached its end position and thus the diaphragm of the delivery pump is in the filling position.

If a liquid sensor is present, the controller can report the entry of liquid into the drive chamber upon receipt of a corresponding signal and emit an alarm signal so that the diaphragm pump is repaired, in particular the diaphragm is replaced, or the entire pump unit is replaced with a new one becomes.

As a result, the interruption in operation of the storage device is kept to a minimum, especially since only the actively controllable inlet valve of the corresponding pump unit has to be closed for this and the pump unit can be detached from its connections and removed after completing a last delivery stroke.

If the pump unit contains a pressure sensor in the conveyed space - which is not the focus of the invention - the drive pressure could of course be regulated directly on the basis of the measured material pressure, but both The control algorithm for this is complex and the susceptibility of the pressure sensor speaks against such a solution.

c) Embodiments

Figur 1a:

die Pump-Einheit am Ende des Füll-Hubes,

Figur 1b:

die Pump-Einheiten in Mittelstellung (Normalstellung),

Figur 1c:

die Pump-Einheiten am Ende des Förder-Hubes,

Figur 2:

die gesamte Lagervorrichtung mit einer Pump-Einheit,

Figur 3a:

eine Aufsicht auf den Vorratsbehälter von oben,

Figur 3b:

einen Horizontalschnitt durch den Vorratsbehälter entlang der Linie B - B der Figur 2,

Figur 4a - d:

Kennlinien zum Betrieb der Pump-Einheit.

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

Figure 1a:

the pump unit at the end of the filling stroke,

Figure 1b:

the pump units in the middle position (normal position),

Figure 1c:

the pump units at the end of the delivery stroke,

Figure 2:

the entire storage facility with a pump unit,

Figure 3a:

a plan view of the storage container from above,

Figure 3b:

a horizontal section through the storage container along the line B - B of Figure 2 ,

Figure 4a - d:

Characteristic curves for operating the pump unit.

The structure of the pump unit 1 can best be seen on the basis of the sectional illustration in FIG Figures 1 detect:
The pump unit 1 consists of a feed pump 1.1 in the form of a diaphragm pump, and a feed pump drive 8 in the form of a pneumatically operated working cylinder, which is located coaxially in front of this diaphragm pump in the direction of movement 10 of the diaphragm 4 serving as the pump element 3 and is connected to it. Unit 1.2, i.e. a pneumatic cylinder 8.

Both the diaphragm 4 and the drive piston 1.2a arranged coaxially with it are designed to be rotationally symmetrical, viewed in the direction of the longitudinal center axis 1 ', which is perpendicular to the main plane of the diaphragm 4 and the drive piston 1. 2a, which is approximately horizontal here and at the same time the direction of movement of the drive piston is 1.2a.

The delivery chamber 1.1a has an inlet opening 5a in the upper area, via which the material M can flow into the delivery chamber 1.1a when the inlet valve 5 arranged in the inlet opening 5a is open, the outlet valve 6 then generally being closed.

In the upper area, the delivery chamber 1.1a also has an outlet opening 6a, at which an outlet valve 6 is arranged, so that material M can flow out of this outlet opening when this outlet valve 6 is open, the inlet valve 5 then generally being closed.

In this way, the delivery space 1.1a is filled with material M when the membrane 4 moves away from the inlet opening 5a (filling stroke) and the material M located in the delivery space 1.1a is ejected into the outlet opening 6a when the membrane 4 moves towards the outlet opening 6a (delivery stroke)

The feed pump 1.1 is driven, that is, its diaphragm 4 is alternately moved back and forth transversely to its main plane 4 ', by means of a drive plunger 9 that engages in the center of the diaphragm 4 on its rear side, ie from the drive space 1.1b.

The feed pump drive 8 in the form of a pneumatic cylinder 8 comprises a drive piston 1.2a, which can be moved back and forth in a drive cylinder 1.2b between two end positions, in particular two stops preferably in the same direction of movement in which the membrane 4 of the membrane feed pump 1.1 coupled to the feed pump drive 8 can also move.

The effective area of the drive piston 1.2a is larger, about twice as large as that of the diaphragm 4, in order to apply the necessary force to the diaphragm with a relatively low pressure of the drive medium introduced into the drive cylinder 1.2b, here compressed air 4 to be able to apply.

The pneumatic cylinder 8 has a compressed air connection 13 at least as shown on the pressure side of the drive piston 1.2a facing away from the membrane 4 and the feed pump 1.1 in the working chamber of the drive cylinder 1.2b, but such a compressed air connection is usually also on the on the other side of the drive piston 1.2a, the pulling side, in order to be able to actively and thus more quickly withdraw the membrane 4 from the inlet opening 5a and to accelerate the filling of the feed pump 1.1.

The compressed air connection 13 is preceded by a proportional valve 18 which is connected to the controller 1 * of the pump unit 1 and can be controlled by it, as described above. Constant knowledge of the position of the drive piston 1.2a is essential for this, which is why a position sensor 17 is arranged in the bottom of the drive cylinder 1.2b, preferably in the form of a distance sensor, which measures the distance between the drive piston 1.2a and the bottom of the cylinder 1.2b and reports 1 * to the controller.

The pump unit 1 preferably also has a negative pressure connection 12, specifically in the drive chamber 1.1b of the feed pump 1.1, whereby the filling process can be supported, especially when the storage container 101 from which the material M is removed also is under negative pressure.

A liquid sensor 15 is preferably arranged in the side of the membrane 4 facing away from the conveying chamber 1.1a, the drive chamber 1.1b, which detects material M which has penetrated there, which is at most in the event of a leak in the membrane 4 itself or its circumferential side Restraint occurs.

The drive piston 1.2a is connected to the diaphragm 4 via a drive plunger 9, which is arranged centrally, that is to say running along the axial direction 10, and is attached to the diaphragm 4 on its rear side, that is to say the side of the drive chamber 1.1b is.

The drive tappet 9 is constructed in several parts:
On the one hand, it comprises the shaft 9.1, which essentially bridges the distance from the drive piston 1.2a to the membrane 4, and a pressure plate 9.2, which is located on the membrane-side end of the shaft 9.1 and with a large-area contact surface 9a on the membrane 4 is applied.

In cross-section, the membrane 4 has, in addition to the main part 4, which is continuous between the edge-side clamps, an annular extension 4.1 on the drive side, the inner circumference of which ends freely and the outer circumference of which is integrally connected to the rear of the main part 4.

In the space between the main part 4 and the extension 4.1 there is a tension plate 9.3, which has a handle centrally on its rear side which protrudes through the opening of the extension 4.1 in the direction of the shaft 9.1 and is connected to it, preferably screwed into it.

This tension plate 9.3 can only be positively connected to the membrane 4 and used again after the membrane 4 has been changed, or it can be firmly connected to the membrane 4, for example glued, and must then be changed together with it.

The pulling plate 9.3 is used to be able to retract the membrane 4 with a large contact surface in the form of the extension 4.1 in the event of a rapid backward movement of the drive piston 1.2a, which is effected by means of compressed air.

The Figures 1a 1 to c show the various functional positions of the drive piston 1.2a and of the membrane 4.

As can be seen, in the middle position of the drive piston 1.2a according to FIG Figure 1b the membrane 4 slightly arched in the center in the direction of the conveying space 1.1a in the form of a bulge 4a, and in the edge area between the outer restraint and the central part resting on the tension plate 9.3, viewed in cross section, slightly curved in the direction of the drive space 1.1b in the form of a annular bulge 4a, creating a radial length reserve for the two end positions:
When the drive piston 1.2a is at the end of the delivery stroke, in particular it rests against an axial stop formed on the drive cylinder 1.2b according to FIG Figure 1c , this bulge is pulled smooth, and the membrane 4 almost reaches the inlet opening 5a and the outlet opening 6a, but not until contact, in order to avoid damage to the membrane 4 by the edges of these openings.

In the other end position according to Figure 1a , at the end of the filling stroke and the beginning of the delivery stroke, that is, when the delivery space 1.1a is completely filled with material M and the piston 1. 2a is at another axial stop of the cylinder 1.2b is applied, the middle area of the membrane 4 lies further away from the inlet opening 5a and the outlet opening 6a than the edge of the membrane 4, which is tightly clamped in the pump housing 2, so that in the radial area in between in particular the Membrane 4 is curved in the opposite direction to the curvature in the central, central area.

The inlet valve 5 as well as the outlet valve 6 is in the Figures 1a - c designed as an active, ie driven, shut-off valve 14.

The outlet valve 6, on the other hand, can also be designed as a simple check valve 7, as in FIG Figure 1b in that in this case a ball as valve body 7.1 rests on the upward-facing valve seat 7.2 due to gravity when the pressure is the same on both sides of the valve body 7.1, and of course even more so when on the side of the valve body 7.1 facing away from the valve seat 7.2 higher pressure than on the other side.

For this reason, the valve unit 6 should preferably be arranged within the storage device 100 with an outlet valve 6 pointing upwards with the valve seat 7.2 and preferably lower than the storage container 101.

The Figures 4a to 4d show how the control at the outlet opening 6a can provide a constant material pressure which is also predetermined with regard to the absolute height, exclusively by means of the monitored axial position of the drive tappet 9 or the drive piston 1.2a as input.

A maximum of 10%, better still a maximum of 5%, is permitted as a deviation from the absolute target value. A constant material pressure is understood to mean that the difference between the highest and the lowest value is a maximum of 10%, better a maximum of 5% of the lowest value.

For this purpose, the control merely controls the drive pressure pA of the drive medium, in the regulating air with which the driving pneumatic cylinder 8, that is to say the drive piston 1.2a in the cylinder 1.2b, is acted upon.

Since the drive pressure pA is controlled via the position of a pressure regulating valve 18, here in the form of an electrically operated proportional valve 18 in the supply line for the drive medium, the controller only changes the current yV with which the electric proportional valve 18 is controlled becomes.

The controller thus controls the drive pressure in the form of the current yV of the electric proportional valve 18 as a function of the axial position xK of the drive tappet 9, in particular of the piston 1.2a of the working cylinder unit, i.e. according to a drive pressure-position characteristic curve, as shown in FIG Figure 4c is shown.

• entweder in Kenntnis der Form der Membran 4 sowie der Größe des Förder-Raumes 1.1a und des Antriebs-Raumes 1.1b, gegebenenfalls unter zusätzlicher Berücksichtigung der Elastizität der Membran 4 und/oder der Viskosität des zu fördernden Materials M
• oder in Kenntnis des Übersetzungsverhältnisses der Pumpeinheit 1 an jeder axialen Position xK durch Vergleich von Antriebsdruck pA oder Stromstärke yV mit dem Materialdruck pM.

This drive pressure-position characteristic curve can be determined from a material pressure-position characteristic curve of the material pressure pM over the axial position xK of the drive tappet 9, as shown in FIG Figure 4b is shown, which in particular by automatic calculation by means of the controller

• either with knowledge of the shape of the membrane 4 and the size of the conveying space 1.1a and of the drive space 1.1b, possibly with additional consideration of the elasticity of the diaphragm 4 and / or the viscosity of the material M to be conveyed
• or knowing the transmission ratio of the pump unit 1 at each axial position xK by comparing the drive pressure pA or current yV with the material pressure pM.

Such a material pressure-position characteristic is recorded by, in a pump unit 1, which is equipped with a pressure sensor 16a in the delivery chamber 1.1a, with the drive piston 1.2a of the working cylinder unit 1.2 fully retracted and the conveyor filled with material -Raum 1.1a on the working cylinder unit 8, a constant drive pressure, for example 6 bar, is applied - as in Figure 4a shown - which can be the case, for example, with a fully open proportional valve 18 and a corresponding control current yV applied to it.

Then step by step - with pauses of several, in particular at least 5 s, better at least 10 s, better at least 20 s in between - a defined withdrawal volume of material M is withdrawn from the connected consumer from the conveying space 1.1a. As a rule, the material pressure pM falls in each case and, after the withdrawal has ended, i.e. when the piston 1.2a has come to a standstill again, rises again to a material pressure pM which is approximately, but not necessarily exactly, that which was present before the withdrawal Material pressure pM.

The withdrawal volume should correspond to a maximum of a fifth, better to a maximum of a tenth, better to a maximum of a twentieth of a whole stroke volume of the feed pump 1.1.

Between the individual removal steps, when the drive piston 1.2a is at a standstill, its axial position xK and the associated material pressure pM are measured, which corresponds to the desired material pressure-position characteristic curve Figure 4b in the form of a polygon, which can also be smoothed to a curve by interpolation.

The drive pressure-position characteristic curve converted from this according to Figure 4c is used during operation in such a way that the control current yV corresponding to the axial zero position at the proportional valve 18 is set. As a result of the subsequent - step-by-step or continuous - removal of material by the consumer, the drive piston 1.2a moves forward.

The pump units 1 used for operation are identical to the pump unit 1 with which the material pressure / position characteristic curve was determined, except for the fact that they do not require a pressure sensor 16.

As soon as a drive pressure-position characteristic according to Figure 4c In the form of a polygon train, the axial position of the next value pair of the polygon train is reached, the control current yV at the proportional valve 18 is changed to the value of this value pair corresponding to this new axial position and maintained until the axial position of the next value pair of the polygon is reached. Train.

If the polygon was smoothed into a curve, this adaptation of the control current yV is carried out continuously in accordance with the now curved drive pressure-position characteristic.

The drive pressure-position characteristic required for the control can also be determined experimentally from the material pressure-position characteristic:
After a first material pressure-position characteristic curve has been recorded at constant drive pressure pA as described above, this can be repeated several times, but with drive pressures pA adjusted manually at the individual axial positions that of the deviation of the material pressure-position characteristic curve achieved from a horizontal in the diagram of Figure 4b is counteracted.

As a result, a horizontal material pressure-position characteristic curve according to Figure 4d can be achieved, and the Working pressure position characteristic with which this is achieved is the desired characteristic according to Figure 4c .

The Figures 2 and 3a, b show the entire storage device 100, comprising a pot-like storage container 101 which can be tightly closed by a lid 101.2 and which can be filled or refilled with material M via an inlet opening 103, and the two outlet openings 102 in the base 108 possesses - as best in the horizontal section of the Figure 3b can be seen to each of which one of the previously described pump units 1 is connected with its inlet nozzle 5a.

The at least one inlet opening 103 is positioned in such a way that the material M falling down therefrom at an impact point 110a1 - see FIG Figure 3b - meets a truncated cone-shaped discharge surface 110a of a discharge body 110 and flows on this downward and radially outward to its lower drip edge 109 in a thin layer and degassed in the process.

Since the wall of the pot 101.1 is not vertical, but is slightly inclined radially upwards and outwards, and the drip edge 109 is in the upper region of the storage container 101 near the inner surface 107a of the wall 107, the material M flows down from the drip edge 109 and impinges on the inner surface 107a of the wall 107, on which it continues downward as a thin layer and continues to degas.

The pump units 1 are arranged symmetrically to the vertical V, the axial direction 101 'of the storage container 101, with their membrane planes 4' of the feed pumps 1.1 lying horizontally.

As a rule, it should be strictly avoided that air gets into the material M in the form of air pockets, which is why the storage container 101 is usually closed airtight, that is, the lid 101.2 shown here is tightly attached to the pot 101.1 of the storage container 101.

In this case, the storage container 101 is under a negative pressure, in that in addition to the inlet opening 103 there is also a negative pressure connection 104 in the cover of the storage container 101 - see the top view in FIG Figure 3a - is available.

Also show the Figures 2 and 3a likewise at least one container inlet valve 115 for material M - of which two can be present in this case according to Figure 3a , for example once for admitting new material M from the storage container 101 and once for returning recirculated material M - as well as a viewing window 116 through which the interior of the storage container 101 can be seen.

How Figure 2 also shows, the storage container 101 can on the one hand comprise a stirrer 106 which, in particular near the bottom 108 of the storage container 101, prevents heavy constituents of the material M from sedimenting by rotating about an upright axis.

The motor 111, which drives the stirrer 106, together with its connection box 117 is mounted on the top of the cover 101.2 and its motor drive shaft 111a protrudes through this cover 101.2 into the interior of the pot 101.1 in a sealed manner and is with the upper ends of the stirrer blades 112a , b, c - best see the sectional view of the Figure 3b - connected.

Their vertical arms 118 extend from there downwards and outwards and then parallel to the wall 107 of the pot 101.1 downwards to near the bottom 108 of the pot 101, the vertical arms 118 being made of a flat material exist, the horizontal cross-section of which extends with its main direction tangential to the longitudinal center axis 101 ', the axis of rotation of the stirrer 106, so that they generate only a low resistance when rotated.

At the lower end of the vertical arms 118, a stirring plate 119 is arranged at an angle thereto, that is to say with a component in the radial direction that achieves a stirring effect, but only just above the bottom 108.

The agitator blades 112a-c are connected to one another at the lower end via a cross brace 113 for stabilization by being fastened to an annular central plate 113.1, which leaves a passage from bottom to top open in the middle.

A rod-shaped fill level sensor 114 can extend upwards from the bottom 108 through this passage.

The discharge body 110 can be fixedly mounted on the cover 101.2 or can be attached to the stirrer 106 in a rotating manner, preferably on the upper region of the stirrer blades 112 a - c.

Furthermore, a heating device 107 in the form of heating wires, for example, can be present in the storage container 101, in particular in its wall, in order to heat the material M and thereby make it thinner.

REFERENCE LIST

1

Pumping unit

1'

Longitudinal central axis

1*

control

1.1

Feed pump

1.1a

Funding room

1.1b

Drive room

1.2

Working cylinder unit, drive working cylinder

1.2a

Drive piston

1.2b

Drive cylinder

2

Feed pump housing

3

Pumping element

4th

elastic element, membrane, main part, bellows

4.1

Membrane extension

4a, b

Rejection

4 '

Main level

5

Inlet valve

5a

Inlet opening

5b

Connection piece

6th

outlet valve

6a

Outlet opening

6b

Connection nozzle, outlet nozzle

7th

check valve

7.1

Valve body

7.2

Valve seat

8th

Feed pump drive

9

Drive tappet

9a

Contact area

9.1

shaft

9.2

printing plate

9.3

Tension plate

10

Direction of movement, axial direction

11

vertical

12th

Vacuum connection

13th

Compressed air connection

14th

Lock valve

14a

Valve body

14b

Valve seat

15th

Liquid sensor

16a, b

Pressure sensor

17th

Position sensor

18th

Proportional valve

100

Storage device

100 *

control

101

Storage container

101 '

Longitudinal central axis

101.1

pot

101.2

cover

102

Outlet opening

103

Inlet opening

104

Vacuum connection

105

Vacuum pump

106

Stirrer

107

Wall

107a

Inner surface

108

ground

109

Edge, drip edge

110

Dissipator

110 '

Axis of rotation

110a

Deflection surface

110a1

Impact point

111

Stirrer drive, motor

111a

Motor shaft, output shaft

112a, b, c

Impeller

113, 113a, b, c

Cross bracing

113.1

Central plate

114

Level sensor

115

Inlet valve

116

Viewing window

117

Junction box

118

Vertical arm

119

Stir plate

M.

material

V

vertical

Claims (17)

Pump unit (1) for emptying a storage container (101) filled with liquid or pasty material (M), in particular under negative pressure, in particular a mixing container (101) which is part of a storage device (100), in which
the pump unit (1) comprises a feed pump (1.1) which - A pump element (3) which can be moved relative to the feed pump housing (2) in the direction of movement (10), - A feed pump drive (8), and - a controller (1 *) for controlling at least all movable components of the pump unit (1)
having, where - the pump element (3) at least comprises an elastic element (4), preferably an elastic element (4), - the feed pump drive (8) comprises a drive plunger (9) which is movable and driven in the direction of movement (10) and which is operatively connected to the elastic element (4), preferably on the side of the drive space (1.1b),
characterized in that - A position sensor (17) for determining the respective position of the pump element (3) or the feed pump drive (8), in particular the drive plunger (9), is present along the entire path of movement, in particular - The elastic element (4) is an, in particular, essentially flat, membrane (4) which is attached on its periphery tightly to the inner sides of the feed pump housing (2) and the feed pump (1.1) is a membrane feed pump (1.1) is. Pump unit for according to one of the preceding claims,
characterized in that
the position sensor (17) is designed as a distance sensor (17) and in particular - Is arranged on the rear side of the drive tappet (9) facing away from the pump element (3) and measures the position of the drive tappet (9),
and or - Is arranged in the drive chamber of the feed pump (1.1) and measures the axial position of the pump element (3), in particular the membrane (4). (Shape of contact surface) Pump unit for according to one of the preceding claims,
characterized in that - the contact surface (9a) of the drive plunger (9) to the elastic element (4) viewed in the direction of movement (10) is disc-shaped or ring-shaped and / or - The membrane (4) on the drive side has a membrane extension (4.1) which attaches to the continuous membrane (4) and, viewed in radial cross section, is directed with the association end towards the center of the membrane surface, - Which is arranged in particular in a ring-shaped circumferential manner between the outer edge and the central region of the membrane (4). Pump unit for according to one of the preceding claims,
characterized in that
the membrane (4) in radial cross section in the unloaded initial state - Has an annular bulge (4a) in the direction of the drive chamber 1.1b in the outer edge region of the membrane (4)
and or - Has a bulge (4b) into the conveying space in the central area. Pump unit for according to one of the preceding claims,
characterized in that - The conveyor pump drive (8) is a working cylinder unit (1.2) and - The position sensor (17) is a distance sensor (17) which is arranged in the cylinder (1.2b) of the working cylinder unit (1.2) and - Either the axial distance to a rear end face of the drive tappet (9) or the piston (1.2a) of the working cylinder unit (1.2) measures - or measures the radial distance from the lateral surface of the piston (1.2a), which is inclined to the axial direction, and / or A pressure sensor (16b) is arranged in the drive space 1.1b of the working cylinder unit (1.2).
(Inlet / outlet valve) Pump unit for according to one of the preceding claims,
characterized in that
the diaphragm feed pump (1.1) - an active, controllably movable inlet valve (5)
and or - A passive outlet valve (6), in particular in the form of a check valve (7), includes and thereby - In particular the valve body (7.1) is arranged above the valve seat (7.2) of the check valve (7) and the valve body (7.1) by its own weight, in particular only its own weight, and / or an additional closing force, in particular spring force , is biased into the closed position and / or - Inlet valve (5) and outlet valve (6) are arranged on diametrically opposite sides of the delivery space (1.1a) of the diaphragm delivery pump (1.1). (Vacuum connection) Pump unit for according to one of the preceding claims,
characterized in that
the drive chamber (1.1b) of the diaphragm feed pump (1.1) has a negative pressure connection (12) and can be subjected to negative pressure.
(Drive cylinder) Pump unit for according to one of the preceding claims,
characterized in that - the drive working cylinder (1.2) can be operated pneumatically and, in particular, both working spaces (1.2b) of the working cylinder unit (1.2) each have a compressed air connection (13),
and or - the effective area of the drive piston (1.2a) of the diaphragm drive pump (1.2) is greater by at least a factor of 1.2, better by a factor of 1.4, better by a factor of 1.6, better by a factor of 1.8 than the effective area of the diaphragm (4) of the diaphragm feed pump (1.1). Pump unit for according to one of the preceding claims,
characterized in that - the feed pump housing (2) has a heating device for heating the interior of the feed pump (1.1),
and or - A liquid sensor (15) is present on the drive side of the membrane (4) of the membrane feed pump (1.1)
and or - A pressure sensor (16a) is present in the delivery space (1.1a) or its connection opening. A storage device (100) comprising - A storage container (101) filled with liquid or pasty material (111) in which there is preferably negative pressure, in particular a mixing container (101), and - At least one pump unit (1) according to one of the preceding claims for emptying the container (100),
characterized in that - The storage device (100) comprises two pump units (1), which in particular can be controlled independently of one another,
and or - the inlet valve (5) in the diaphragm feed pump (1.1) is arranged lower than the outlet opening (102) of the storage container (101),
and or - The inlet valve (5) in the assembled state of the diaphragm feed pump (1.1) is arranged at the lowest point and the outlet valve (6) is arranged at the highest point of its delivery space (1.1a). Storage device according to claim 9 or 10,
characterized in that - the diaphragm feed pump (1.1) is arranged with the main plane (4 ') of the diaphragm (4) at an angle of no more than 40 °, better no more than 30 °, better no more than 20 °, better no more than 10 ° to the vertical (11),
and or - the at least one feed pump drive (8) is arranged with respect to the membrane feed pump (1.1) on the side facing away from the longitudinal center (101 ') of the storage container (101) and / or - A connecting line, in particular closable, is present between the air space of the storage container (101) and the drive space (1.1b) of the diaphragm feed pump (1.1), in particular each diaphragm feed pump (1.1). Method for operating the pump unit, in particular for emptying the storage container (101) of a storage device (100) according to one of the preceding claims 6 to 9,
characterized in that
the axial position of a monitored element, namely - the drive tappet (9)
and or - The feed pump drive (8) driving the drive tappet (9) and / or - the membrane (4), in particular a defined point or area of the membrane (4),
is determined directly or indirectly, in particular is constantly determined, in particular the axial position of the monitored element - is determined over the entire movement path and - The control (1 *) of the pump unit (1) uses the position signal to provide a delivery pressure defined for each axial position, in particular a constant delivery pressure, at the outlet opening (6a) of the delivery space (1.1a). Method according to one of the preceding method claims,
characterized in that - The target end positions of the membrane (4) and / or the drive piston (1.2a) are determined by defining the end positions of the membrane (4) once during a calibration run and / or - The controller (1 *) controls the pump drive (8) by changing a control parameter, in particular - The drive pressure (pA) according to a drive pressure-position characteristic between the drive pressure applied to the corresponding drive space (1.1b) of the drive cylinder (1.2) and the axial position as a monitored element. Method according to one of the preceding method claims,
characterized in that
the material pressure (pM) is measured, in particular at the outlet opening (6a), and the controller (1 *) controls the pump drive (8) by changing the drive pressure (pA) according to a drive pressure-material pressure characteristic between the the drive pressure (pA) applied to the corresponding working space of the drive cylinder (1.2) and the material pressure (pM)
and or
the drive pressure is changed by controlling a proportional valve in the supply line for the drive medium.
(Safety function) Method according to one of the preceding method claims,
characterized in that - The characteristic curve is determined, in particular automatically calculated by the control (1 *), knowing the shape of the membrane (4) as well as the conveying space (1.1a) and the drive space (1.1b), from an output characteristic curve , - The output characteristic is recorded by performing a delivery stroke while keeping the drive pressure (pA) constant and recording the material pressure (pM), at least at individual axial positions of the drive piston (1 2a) over the movement path of the drive piston ( 1.2a). Method according to one of the preceding method claims,
characterized in that - The ejection movement of the drive plunger (9) of one pump unit (1) is started before the ejection movement of the drive plunger (9) of the other pump unit (1) has ended
and or - the drive space (1.1b) of the diaphragm feed pump (1.1) is subjected to negative pressure, in particular with the same negative pressure as the air space of the storage container (101), in particular as soon as the ejection movement of the drive plunger (9) finished or permanent and / or - The inlet valve (5) is closed as soon as the position sensor (17) reports that the end position of the membrane (4) has been reached by the feed pump (1.1) in the filling position. Method according to one of the preceding method claims,
characterized in that - The control (1 *) emits an alarm signal as soon as the liquid sensor (15) in the drive space (1.1b) of the conveyor pump (1.1) reports liquid and / or - The control (1 *) stops the feed pump drive (8) as soon as a pressure sensor (16) present in the feed space (1.1a) reports a pressure above a predetermined limit value.

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