EP3020974A1 - System for conveying viscous media, method of operating such a system and corresponding transport unit - Google Patents

Abstract

Method and system for conveying viscous media with a positive displacement pump (10) and a delivery unit (20) arranged in the flow direction of the viscous medium before the positive displacement pump (10) and fluidly connected to the positive displacement pump (10), wherein the positive displacement pump (10) and the conveyor unit (20) independent of each other drive units (11, 21) and are arranged in a line, so that a conveying direction of the conveyor unit (20) coaxially aligned with a rotational axis of the positive displacement pump (10).

Description

The invention relates to a system for conveying viscous media and a method for operating such a system. Furthermore, the invention relates to a conveyor unit for a previously mentioned system.

From practice systems for the promotion of viscous media are known, which are composed of a positive displacement pump and a conveyor unit. The delivery unit and the positive displacement pump are coupled to each other in a fluid-tight manner. Such systems are used, which combine a displacement pump with a delivery unit, in particular when transporting viscous media. Such media are usually difficult or impossible to flow, so that for a continuous pumping forced delivery of the medium is required in the pump.

The supply of the media in the positive displacement pump takes place from above or from the side, so that the medium to be conveyed undergoes a change in direction before the compression in the positive displacement pump. In practice, it has been shown that such systems are susceptible to failure, in particular because of the change in the conveying direction. Consequently, process reliability can not be completely guaranteed.

Other systems lead the medium to be pumped horizontally in the positive displacement pump. For this purpose, the delivery unit is coupled to the drive of the positive displacement pump to achieve the forced supply of the medium. The delivery movement of the delivery unit is therefore directly dependent on the pumping movement of the positive displacement pump. This has the disadvantage that the system can not be used arbitrarily for different viscous media. Rather, the possibilities are very limited.

The object of the invention is to provide a system for conveying viscous media, which offers increased reliability and thus improves process reliability, and to promote different media is customizable. It is another object of the invention to provide a method for operating such a system as well as a suitable conveyor unit.

According to the invention, this object is achieved with respect to the system by the subject-matter of patent claim 1, with regard to the method of operation by the subject-matter of claim 13 and with regard to the conveyor unit by the subject-matter of claim 15.

In particular, the invention is achieved by a system for conveying viscous media, which has a positive displacement pump and a delivery unit. The delivery unit is arranged in the flow direction of a viscous medium before the positive displacement pump and fluidly connected to the positive displacement pump. In this case, the positive displacement pump and the delivery unit can have mutually independent drive units. The displacement pump and the delivery unit are preferably arranged in a line, so that a conveying direction of the delivery unit is aligned parallel, in particular coaxially, to a rotational axis of the positive displacement pump.

It has been shown that the line-consistent or rectilinear alignment of the delivery unit to the positive displacement pump reduces the susceptibility of the system as a whole. By transferring the medium to be conveyed from the delivery unit into the positive displacement pump essentially without a change of direction, a particularly reliable and continuous transport of the medium is ensured. This increases process reliability. Overall, a particularly efficient, active promotion of the medium is achieved in the positive displacement pump in this way.

The controllability of the system is improved in the invention in that both the positive displacement pump and the delivery unit have a drive unit, wherein the drive units of the positive displacement pump and the delivery unit are independent of each other. In other words, there are each associated with a separate drive unit of the positive displacement pump and another separate drive unit of the conveyor unit. Thus, the system can be used for different viscous media, with the appropriate for the transport of the respective medium parameters are easily adjustable. Overall, the change of media to be funded is easy and fast to implement.

In a preferred embodiment of the system according to the invention, the positive displacement pump, a first drive unit and the conveyor unit to a second drive unit, wherein at least one speed of the first drive unit is independent of a speed of the second drive unit adjustable.

The speed of the positive displacement pump and the delivery unit is a relevant parameter for promoting different viscous or non-flowable media. The independently adjustable speed of the positive displacement pump and the delivery unit therefore allows a good adaptation to different viscous media and thus increases the capabilities of the system.

The positive displacement pump may be an eccentric screw pump or a screw pump. Such pumps are particularly gentle to the product and are characterized by a simple and hygienic cleaning ability. In this respect, such pumps are particularly suitable for use in the food industry, for example for conveying doughs in bakery production.

Alternatively, a rotary piston pump, a rotary piston pump or a gear pump can be used as positive displacement pump. In each case, it is provided that the delivery unit can be positioned and connected to the positive displacement pump such that a rectilinear supply of the medium to be delivered takes place in the positive displacement pump.

The delivery unit may have a stuffing piston or a moving floor or a screw conveyor. For a continuous supply of the media to be conveyed is particularly suitable a screw conveyor. Depending on the nature of the medium to be pumped, the use of a stuffing-type piston or a sliding bottom can also be used as a conveying unit. The skilled person selects here depending on the purpose of the appropriate type of conveyor.

It is particularly preferred to use a screw conveyor as the conveying unit. The screw conveyor may have at least one screw. It is also possible that the screw conveyor comprises a plurality of screws, which are arranged parallel to each other. In that sense, the supply of the viscous Medium into the positive displacement pump by a twin screw conveyor or a multi-screw conveyor.

The at least one screw of the screw conveyor has an axis of rotation, which may preferably be arranged parallel, in particular coaxially to a rotational axis of the positive displacement pump. This ensures that a rectilinear feed of the medium to be pumped takes place in the positive displacement pump.

The screw can be configured as a full screw or as a hollow screw. The full screw generates a relatively larger delivery thrust and thus ensures a good supply of the medium in the positive displacement pump. For media that tend to stick, but there is a risk of conveyor stop by rolling. The hollow screw on the other hand has advantages in terms of kneading and also provides good ventilation and compaction of the medium to be delivered.

In a further preferred embodiment of the invention, the conveyor unit has a closed area, an open area and an ejection area. The closed area may be located between the open area and the ejection area. The tripartite division of the delivery unit is preferably accompanied by a separation of functions.

Thus, the open area for the supply of the medium can be used in the conveyor unit. The closed area serves for compaction and compression of the medium. The ejection area forms a transition between an interior of the delivery unit and the positive displacement pump.

In a particularly preferred variant, the closed area has an exchangeable bearing. The bearing can be designed as a plain bearing, in particular as a plain bearing sleeve. In particular, the closed region may comprise an inner wall which is designed as a sliding surface. As a result, a screw conveyor of the screw conveyor can be supported and stored by the housing of the conveyor unit itself. The worm is thus slidably mounted at a longitudinal axial end in the closed area, wherein the inner surface of the housing of the conveyor unit forms a sliding surface on which the worm rotates. This simplifies the design of the conveyor unit.

In a preferred embodiment, the ejection region can taper conically to form an outlet opening. A cone-shaped design of the ejection region is particularly useful for transporting flowable media. In the transport of non-flowable, in particular puncture resistant, media, however, it has proven to be advantageous if the ejection region is longitudinally limited by a plate having an outlet opening. The plate is preferably aligned perpendicular to a longitudinal axis of the conveyor unit.

Also advantageous is an embodiment of the system according to the invention, in which the conveyor unit, in particular in the closed area and in the ejection area, has a continuous rectilinear inner floor, preferably aligned in a horizontal plane. In particular, a lower foot line of the inner bottom of the positive displacement pump and the delivery unit may be rectilinear.

The outlet opening of the conveyor unit is advantageously arranged so that its lower edge is arranged in the foot line and is aligned with the rectilinear inner bottom. This has the advantage that rinsing water, which is used to clean the system, collects on the inner bottom and is thus easily removable. Overall, therefore, the downtime of the system can be reduced for cleaning purposes.

In this context, it is particularly advantageous if the delivery unit, preferably in the open area, has a cleaning opening which extends through the inner bottom. The cleaning opening is preferably arranged at the lowest point of the system, so that cleaning liquid, for example rinsing water, can flow well through the cleaning opening. The cleaning opening can be closable.

In the context of the present application, a method for conveying a viscous medium is also disclosed and claimed, in which a previously described system is used. In the method according to the invention, the medium can advantageously be guided in a straight line, in particular without a change in direction, from the delivery unit into the positive displacement pump. In addition, it can be provided that the delivery unit and the positive displacement pump are controlled or regulated independently of each other.

With the described method can be reacted quickly and easily to a change in the composition of the medium to be delivered. In particular, can be favorably influenced by the separate control or regulation of the delivery unit and the positive displacement pump, the overall process, which increases the overall efficiency in production.

It is preferred to regulate a rotational speed of the delivery unit and / or of the positive displacement pump as a function of a pressure of the medium within the positive displacement pump and / or as a function of a temperature of the positive displacement pump. In the method, therefore, a control can take place in an advantageous manner, which takes into account the pressure of the medium and / or the temperature of the positive displacement pump.

For example, the speed of the delivery unit can be reduced if the pressure of the medium exceeds a predetermined maximum. Likewise, the speed of the positive displacement pump and / or the delivery unit can be reduced if the temperature of the positive displacement pump exceeds a predetermined maximum. Overall, this ensures process reliability and enables optimal transport performance with low failure risk.

Another subsidiary aspect of the invention relates to a delivery unit for a system described above for the promotion of viscous media. It is provided that the delivery unit has a connection flange for fluid-tight connection with a positive displacement pump. The features and advantages of the conveyor unit described in connection with the overall system apply analogously to the single conveyor unit.

Fig. 1

eine teilweise geschnittene Seitenansicht eines erfindungsgemäßen Systems nach einem bevorzugten Ausführungsbeispiel mit einem konusförmigen Auslassbereich der Fördereinheit, wobei der Auslassbereich eine zentrale Auslassöffnung aufweist;

Fig. 2

eine Draufsicht auf das System gemäß Fig. 1;

Fig. 3

eine teilweise geschnittene Seitenansicht der Fördereinheit des Systems gemäß Fig. 1;

Fig. 4

eine perspektivische Ansicht der Fördereinheit gemäß Fig. 3;

Fig. 5

eine teilweise geschnittene Seitenansicht eines erfindungsgemäßen Systems mit einem konusförmigen Auslassbereich der Fördereinheit, wobei der Auslassbereich asymmetrisch ausgebildet ist, so dass die Auslassöffnung mit einem Innenboden der Fördereinheit fluchtet;

Fig. 6

eine teilweise geschnittene Seitenansicht der Fördereinheit des Systems gemäß Fig. 5; und

Fig. 7

eine teilweise geschnittene Seitenansicht des erfindungsgemäßen Systems nach einem weiteren bevorzugten Ausführungsbeispiel, wobei der Auslassbereich eine Platte mit einer zentralen Auslassöffnung aufweist.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying schematic drawings. Show in it

Fig. 1

a partially sectioned side view of a system according to the invention according to a preferred embodiment with a cone-shaped outlet region of the conveyor unit, wherein the outlet region has a central outlet opening;

Fig. 2

a plan view of the system according to Fig. 1 ;

Fig. 3

a partially sectioned side view of the conveyor unit of the system according to Fig. 1 ;

Fig. 4

a perspective view of the conveyor unit according to Fig. 3 ;

Fig. 5

a partially sectioned side view of a system according to the invention with a cone-shaped outlet region of the conveyor unit, wherein the outlet region is formed asymmetrically, so that the outlet opening is aligned with an inner bottom of the conveyor unit;

Fig. 6

a partially sectioned side view of the conveyor unit of the system according to Fig. 5 ; and

Fig. 7

a partially sectioned side view of the system according to the invention according to a further preferred embodiment, wherein the outlet region has a plate with a central outlet opening.

The embodiments described in detail below each represent a system for conveying viscous media, which has a positive displacement pump 10 and a delivery unit 20. The positive displacement pump 10 can be designed as an eccentric screw pump or as a screw pump. Other positive displacement pumps 10 are possible. For example, a rotary piston pump, a rotary pump or a gear pump can be used.

The positive displacement pump 10 has a first drive unit 11, which forms a direct drive for the positive displacement pump 10. The first drive unit 11 is preferably designed as a separately controllable electric motor.

The positive displacement pump 10 has a connecting flange 13 which limits an inlet opening. Through the connecting flange 13, the positive displacement pump 10 can be coupled in a fluid-tight manner to the delivery unit 20. Furthermore, a pump outlet 12 is provided which can be connected, for example, to a pipeline. In the embodiments illustrated here, the pump outlet 12 is aligned at right angles to the connecting flange 13. In other words, there is a change in the conveying direction for the viscous medium in the positive displacement pump 10. This applies to all illustrated embodiments. It is advantageous in the system described here that the change in the conveying direction or transport direction takes place only after the introduction of the viscous medium in the positive displacement pump 10. The supply in the positive displacement pump 10 through the inlet opening on the connecting flange 13 is rectilinear. For this purpose, the conveyor unit 20 is designed accordingly.

In general, the delivery unit 20 has an open area 14, a closed area 15 and an ejection area 16, respectively. Through the open area 14 and the closed area 15 extends a screw 24, which is designed here as a hollow screw. Alternatively, it is possible to use a full screw as a screw conveyor.

The use of a push floor or Stopfkolbens is conceivable instead of a screw conveyor. In any case, it is provided that the conveying direction is aligned parallel, in particular coaxially, to a longitudinal axis of the positive displacement pump 10. This ensures that before the positive displacement pump 10, the medium to be conveyed undergoes no change in direction, which has been found to be advantageous for the efficiency of the system.

The conveyor unit 20 has a second drive unit 21. The second drive unit 21 may be formed by a separately controllable electric motor.

The two drive units 11, 21 of the positive displacement pump 10 and the delivery unit 20 are preferably connected to a common control, wherein the controller is designed such that both drive units 11, 21 are independently controllable. In particular, the rotational speed of the first drive unit 11 and the second drive unit 21 can be independently adjustable.

The controller may include a control, which causes an automatic adjustment of the rotational speeds of the drive units 11, 21 based on predetermined parameters. For example, the speed of the first drive unit 11, which acts on the positive displacement pump 10, depending on a temperature of the positive displacement pump 10 and / or a pressure of the medium to be delivered at the pump outlet be adjustable.

Likewise, the speed of the second drive unit 21, which acts on the screw 24, depending on a pressure of the medium in the ejection region 16 may be adjustable. It is preferably provided that the control or regulation of the system takes place mainly by means of the flow rate of the medium to be delivered by the positive displacement pump 10. This serves process reliability. As part of a protective function is preferably provided to use the power consumption of the second drive unit 21 of the conveyor unit 20 as a parameter for the control or regulation. The current consumption of the second drive unit serves as an indicator of an overload of the conveyor unit.

Once a predetermined threshold is exceeded, therefore, the system is switched off to protect against damage or at least reduces the speed of the second drive unit 21. To determine the aforementioned parameters, the system preferably has corresponding sensors which are connected to the controller or regulation.

As can be seen in the figures, the second drive unit 21 of the conveyor unit 20 may be coupled via a deflection gear 33 with the worm 24, which is connected by a drive shaft 23 to the deflection gear 33. The worm 24 extends through the open area 14, which has a feed opening 25. The feed opening 25 can be connectable, for example, to a pouring funnel in order to introduce the medium to be conveyed into the feed unit 20.

A free end of the screw 24 is arranged in the closed area 15. The closed region 15 has a plain bearing in the form of a plain bearing sleeve 26, the inner diameter of which essentially corresponds to the outer diameter of the screw 24. The plain bearing sleeve 26 may have at least on its inner surface a sliding coating, which may be formed for example by a plastic. Alternatively, it is possible that the plain bearing sleeve 26 as a whole consists of a material, in particular a plastic, which has sliding properties.

The plain bearing sleeve 26 thus forms a guide and storage for the screw 24. The plain bearing sleeve 26 is interchangeable. For this purpose, two retaining rings 27 are provided, which are connected to each other via threaded rods 28 ( Fig. 4 ). The plain bearing sleeve 26 is fixed so that it clamps between the retaining rings 27. To change the plain bearing sleeve only the threaded rods 28 are to solve, so that the plain bearing sleeve 26 can be separated from the retaining rings 27. Subsequently, a new plain bearing sleeve 26 is positioned between the retaining rings 27 and fixed by means of the threaded rods 28.

It is also possible that the slide bearing sleeve 26 or generally a bearing for the screw 24 is formed in several parts. For example, two half-shells can be provided, which can be connected to one another to form the bearing, in particular the plain bearing sleeve 26. The use of bracing retaining rings can then be dispensed with. The multi-part design of the bearing or the plain bearing sleeve 26 facilitates the assembly of the conveyor unit 20 and simplifies the replacement of the bearing. The above applies to all embodiments of the invention.

With regard to the open area 14 and the closed area 15 as well as the second drive unit 21, the delivery unit 20 is constructed identically in the exemplary embodiments described here. However, differences exist in the shape of the ejection area 16.

In the embodiment according to Fig. 1 to 4 the ejection region 16 has a conical shape, which opens into a central ejection opening 31. The ejection opening 31 is thus aligned concentrically to the axis of rotation of the screw 24. Likewise, the ejection opening 31 is aligned with the axis of rotation of the screw 24 concentrically or coaxially to the axis of rotation of the positive displacement pump 10. This is in the side view according to Fig. 1 and in the plan view according to Fig. 2 good to see.

As in the 3 and 4 can be seen, the concentric cone 34 of the ejection region 16 is integrally formed with a retaining ring 27. Thus, the concentric cone 34 analogous to the plain bearing sleeve 26 can be easily replaced. For example, depending on the medium to be conveyed, an ejection area 16 can be mounted which has a different geometric design. In particular, an asymmetrical cone 35 can be mounted, as in the Fig. 5 and 6 is shown.

In general, the use of a cone-shaped ejection region 16 for conveying or transporting flowable medium is expedient. The asymmetrical cone 35 according to Fig. 5 and 6 has the additional advantage that in this way at least in the ejection area 16 and in the closed area 15 a rectilinear inner bottom 29 is formed. This facilitates the cleaning of the delivery unit 20.

In detail is in the Fig. 5 and 6 recognizable that the inner bottom 29 passes straight into an inner peripheral surface of the positive displacement pump 10. In this respect, also in the embodiment according to Fig. 5 and 6 fed to the medium to be conveyed in a straight line in the positive displacement pump 10. Although the axes of rotation of the screw 24 and the positive displacement pump 10 are offset from one another, they are parallel. The rectilinear inner bottom 29 is lowered in the open area 14, so that in the open area 14 is the lowest point of the entire system.

Advantageously, it is provided to arrange a cleaning opening 32 in the open area 14. The cleaning opening 32 is thus arranged at the lowest point of the overall system, so that rinsing liquid, which is introduced during the cleaning in the conveyor unit 20, can flow independently. This facilitates and speeds up the cleaning process. The device is therefore also suitable for use in hygienically sensitive areas.

A further embodiment which is particularly suitable for transporting or for conveying puncture-resistant or non-flowable media is shown Fig. 7 , The difference from the aforementioned embodiments is that the ejection region 16 is formed by a plate 30. The plate 30 replaces the cone-shaped ejection region 16 of the preceding embodiments. At the same time, the plate 30 forms a retaining ring 27 which fixes the plain bearing sleeve 26.

In the plate 30, an outlet opening 31 is arranged centrally. The outlet opening 31 is aligned coaxially to the axis of rotation of the screw 24 and to the axis of rotation of the positive displacement pump 10. It has been found that the plate 30 assists a particularly even supply of media into the positive displacement pump 10 when the system is used to deliver media having a high internal shear resistance. These are in particular puncture resistant or non-flowable media.

For all embodiments, it is also possible for a full screw to be used instead of the screw 24 designed as a hollow screw. Moreover, it is conceivable to axially provide the worm on both sides with a shaft bearing, to achieve a stable guidance of the screw 24. However, the design effort is increased. Moreover, the bilateral shaft bearing interferes with the conveying path to the displacement pump 10.

Furthermore, for all embodiments that the outlet opening 31 may be designed differently geometric and is preferably adapted to the shape of the inlet opening on the connecting flange 13 of the positive displacement pump 10. For example, the outlet port 31 may have an oval cross-section which is widely used at intake ports 31 of rotary lobe pumps, rotary lobe pumps and screw pumps. Alternatively, the outlet opening 31 can also form a circular cross-section, as a result of which the delivery unit 20 can be easily connected to eccentric screw pumps or gear pumps which also have a likewise circular inlet opening 31.

LIST OF REFERENCE NUMBERS

10

displacement

11

First drive unit

12

pump outlet

13

connecting flange

14

Open area

15

Closed area

16

ejection area

20

delivery unit

21

Second drive unit

22

flange

23

drive shaft

24

slug

25

feed

26

plain bearing sleeve

27

retaining ring

28

threaded rod

29

interior floor

30

plate

31

outlet

32

cleaning opening

33

deflecting

34

Concentric cone

35

Asymmetric cone

Claims (15)

System for conveying viscous media with a positive displacement pump (10) and a delivery unit (20) arranged in the flow direction of the viscous medium in front of the positive displacement pump (10) and fluidly connected to the positive displacement pump (10), wherein the positive displacement pump (10) and the delivery unit (20) independent drive units (11, 21) and are arranged in a line, so that a conveying direction of the conveyor unit (20) parallel, in particular coaxial, is aligned with a rotational axis of the positive displacement pump (10). System according to claim 1,
characterized.
that the displacement pump (10) comprise a second drive unit (21) comprises a first drive unit (11) and the conveying unit (20), wherein at least a rotational speed of the first drive unit (11) independent of a speed of the second prime mover (21) is adjustable. System according to claim 1 or 2,
characterized,
in that the displacement pump (10) is an eccentric screw pump or a screw pump. System according to one of the preceding claims,
characterized,
that the conveyor unit (20) comprises a compaction ram or a walking floor, or a screw conveyor. System according to claim 4,
characterized,
in that the screw conveyor has at least one worm (24), wherein an axis of rotation of the worm (24) is arranged parallel, in particular coaxially, to a rotation axis of the positive displacement pump (10). System according to claim 5,
characterized,
that the worm (24) is designed as a solid screw or as a hollow screw. System according to one of the preceding claims,
characterized,
in that the delivery unit (20) has a closed area (15), an open area (14) and an ejection area (16), the closed area (15) being arranged between the open area (14) and the ejection area (16). System according to claim 7,
characterized,
that the closed area (15) has a replaceable bearing. System according to claim 7 or 8,
characterized,
in that the ejection region (16) tapers conically to form an outlet opening (31). System according to claim 7 or 8,
characterized,
in that the ejection region (16) is bounded longitudinally by a plate (30) which is oriented perpendicular to a longitudinal axis of the conveying unit (20) and has an outlet opening (31). System according to one of the preceding claims,
characterized,
that the conveying unit (20) has a continuous rectilinear, in particular in a horizontal plane aligned, inner bottom (29). System according to claim 11,
characterized,
in that the delivery unit (20), in particular in the open region (14), has a cleaning opening (32) which extends through the inner bottom (29). Method for conveying a viscous medium with a system according to one of the preceding claims,
wherein the medium is guided rectilinearly, in particular without a change in direction, from the delivery unit (20) into the positive displacement pump (10) and wherein the delivery unit (20) and the positive displacement pump (10) are controlled or regulated independently of one another. Method according to claim 13,
characterized,
that a speed of the conveyor unit (20) and / or the positive displacement pump (10) in response to a pressure of the medium within the positive displacement pump (10) and / or a temperature of the displacement pump (10) is regulated. The delivery unit (10) for a system according to any one of claims 1 to 12, wherein the delivery unit (20) has a connection flange for fluid-tight connection with a positive displacement pump (10).

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