EP3020974B1 - System for conveying viscous media, method of operating such a system and corresponding transport unit - Google Patents

Description

The invention relates to a system for conveying viscous media and to a method for operating such a system.

Systems for pumping viscous media are known from practice, which are composed of a displacement pump and a delivery unit. The delivery unit and the displacement pump are coupled to one another in a fluid-tight manner. Such systems are used which combine a positive displacement pump with a delivery unit, especially when transporting viscous media. Such media are usually not or only with difficulty flowable, so that a forced supply of the medium into the pump is necessary for a continuous pumping process.

The media is fed into the displacement pump from above or from the side, so that the medium to be conveyed undergoes a change of direction before it is compressed in the displacement pump, as in the WO 02/18792 A2 . In practice it has been shown that such systems are prone to failure in particular because of the change in the conveying direction. As a result, process reliability cannot be completely guaranteed.

Other systems feed the medium to be conveyed horizontally into the displacement pump. For this purpose, the delivery unit is coupled to the drive of the positive displacement pump in order to achieve the forced supply of the medium, as in FIG DE 101 60 335 A1 . The delivery movement of the delivery unit is consequently directly dependent on the pumping movement of the positive displacement pump. This has the disadvantage that the system cannot be used for different viscous media at will. Rather, the possible uses are very limited.

The object of the invention is to provide a system for conveying viscous media which offers increased reliability and to that extent improves process reliability, as well as for conveying different media is customizable. Another object of the invention is to specify a method for operating such a system.

According to the invention, this object is achieved with regard to the system by the subject matter of claim 1 and with regard to the operating method by the subject matter of claim 13.

In particular, the invention is achieved by a system for conveying viscous media which has a displacement pump and a conveying unit. The delivery unit is arranged upstream of the displacement pump in the direction of flow of a viscous medium and is fluidly connected to the displacement pump. The displacement pump and the delivery unit have independent drive units. The displacement pump and the delivery unit are arranged in a line so that a delivery direction of the delivery unit is aligned coaxially with an axis of rotation of the positive displacement pump.

It has been shown that the true-to-line or straight alignment of the delivery unit with respect to the displacement pump reduces the overall susceptibility of the system to failure. Since the medium to be conveyed is transferred from the conveying unit to the displacement pump essentially without a change in direction, a particularly reliable and continuous transport of the medium is ensured. This increases the process reliability. Overall, a particularly efficient, active delivery of the medium into the displacement pump is achieved in this way.

The controllability of the system is improved in the invention in that both the displacement pump and the delivery unit have a drive unit, the drive units of the displacement pump and the delivery unit being independent of one another. In other words, a separate drive unit is assigned to the displacement pump and a further separate drive unit is assigned to the delivery unit. The system can thus be used for different viscous media, with the parameters appropriate for the transport of the respective medium being easily adjustable. Overall, the change from the media to be funded can be implemented quickly and easily.

In a preferred embodiment of the system according to the invention, the displacement pump has a first drive unit and the delivery unit has a second drive unit, at least one speed of the first drive unit being adjustable independently of a speed of the second drive unit.

The speed of the displacement pump and the delivery unit is a relevant parameter for pumping different viscous or non-flowable media. The independently adjustable speed of the displacement pump and the delivery unit therefore enables good adaptation to different viscous media and thus increases the application possibilities of the system.

The positive displacement pump can be an eccentric screw pump or a screw pump. Such pumps are particularly gentle on the product and are characterized by a simple and hygienically perfect cleaning option. In this respect, pumps of this type are particularly suitable for use in the food industry, for example for conveying dough in the production of baked goods.

Alternatively, a rotary piston pump, a rotary piston pump or a gear pump can be used as the positive displacement pump. It is provided in each case that the delivery unit can be positioned and connected to the positive displacement pump in such a way that the medium to be delivered is fed into the positive displacement pump in a straight line.

The delivery unit can have a stuffing piston or a push floor or a screw conveyor. A screw conveyor is particularly suitable for a continuous supply of the media to be conveyed. Depending on the nature of the medium to be conveyed, the use of a stuffing piston or a push floor as a conveying unit can also be useful. The person skilled in the art selects the suitable type of conveyor unit depending on the intended use.

It is particularly preferred to use a screw conveyor as the conveyor unit. The screw conveyor can have at least one screw. It is also possible that the screw conveyor comprises several screws which are arranged parallel to one another. In this respect, the supply of the viscous Medium into the positive displacement pump through a twin screw conveyor or a multiple screw conveyor.

The at least one screw of the screw conveyor has an axis of rotation which can be arranged preferably parallel, in particular coaxially, to an axis of rotation of the positive displacement pump. This ensures that the medium to be conveyed is fed into the positive displacement pump in a straight line.

The screw can be designed as a full screw or as a hollow screw. The full screw generates a comparatively larger delivery thrust and thus ensures that the medium is well fed into the positive displacement pump. In the case of media that tend to stick, however, there is a risk of the conveyor stopping due to roller formation. In contrast, the hollow screw has advantages in terms of kneading ability and also offers good ventilation and compaction of the medium to be conveyed.

In a further preferred embodiment of the invention, the delivery unit has a closed area, an open area and an ejection area. The closed area can be arranged between the open area and the ejection area. The division of the delivery unit into three is preferably accompanied by a separation of functions.

The open area can thus be used to feed the medium into the delivery unit. The closed area is used to compact and compress the medium. The discharge area forms a transition between the interior of the delivery unit and the displacement pump.

In a particularly preferred variant, the closed area has an exchangeable bearing. The bearing can be designed as a slide bearing, in particular as a slide bearing sleeve. In particular, the closed area can 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 screw is thus slidingly mounted at a longitudinal axial end in the closed area, the inner surface of the housing of the conveyor unit forming a sliding surface on which the screw slides in a rotating manner. This simplifies the construction of the conveyor unit.

In a preferred embodiment, the ejection area can taper conically to form an outlet opening. A conical design of the ejection area is particularly useful for the transport of flowable media. In the case of the transport of non-flowable, in particular puncture-proof, media, however, it has proven to be advantageous if the ejection area is delimited longitudinally and axially by a plate which has an outlet opening. The plate is preferably aligned perpendicular to a longitudinal axis of the conveyor unit.

An embodiment of the system according to the invention is also advantageous in which the conveyor unit, in particular in the closed area and in the ejection area, has a continuously straight inner base, preferably oriented in a horizontal plane. In particular, a lower base line of the inner base of the displacement pump and the delivery unit can be designed in a straight line.

The outlet opening of the conveyor unit is advantageously arranged in such a way that its lower edge is arranged in the base line or is flush with the straight inner base. This has the advantage that rinsing water, which is used to clean the system, collects on the inner floor and can therefore be easily removed. Overall, the downtimes of the system for cleaning purposes can thus be reduced.

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 base. The cleaning opening is preferably arranged at the lowest point of the system, so that cleaning liquid, for example rinsing water, can easily flow off 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 is advantageously guided in a straight line from the delivery unit into the displacement pump. In addition, it can be provided that the delivery unit and the displacement pump are controlled or regulated independently of one another.

With the method described it is possible to react quickly and easily to a change in the composition of the medium to be conveyed. In particular, the separate control or regulation of the delivery unit and the displacement pump can advantageously influence the overall process, which increases the overall efficiency in production.

It is preferred to regulate a speed of the delivery unit and / or the displacement pump as a function of a pressure of the medium within the displacement pump and / or as a function of a temperature of the displacement pump. In the method, a regulation can thus advantageously take place which takes into account the pressure of the medium and / or the temperature of the displacement pump.

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

In a delivery unit for a previously described system for delivering 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 delivery unit described in connection with the overall system apply analogously to the stand-alone delivery 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 conical outlet area of the conveyor unit, the outlet area having a central outlet opening;

Fig. 2

a top 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 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 conical outlet area of the conveyor unit, the outlet area being asymmetrical 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 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 area has a plate with a central outlet opening.

The exemplary embodiments described in detail below each represent a system for conveying viscous media which has a displacement pump 10 and a conveying unit 20. The 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 piston 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 delimits an inlet opening. The positive displacement pump 10 can be coupled to the delivery unit 20 in a fluid-tight manner through the connecting flange 13. A pump outlet 12 is also provided, which can be connected to a pipeline, for example. In the exemplary embodiments illustrated here, the pump outlet 12 is each aligned at right angles to the connecting flange 13. In other words, there is a change in the delivery direction for the viscous medium in the 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 only takes place after the viscous medium has been introduced into the displacement pump 10. The supply into the positive displacement pump 10 through the inlet opening on the connecting flange 13 takes place in a straight line. For this purpose, the delivery unit 20 is designed accordingly.

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

The use of a push floor or a stuffing piston is also 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 the medium to be conveyed does not experience a change in direction upstream of the displacement pump 10, which has proven to be advantageous for the efficiency of the system.

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

The two drive units 11, 21 of the displacement pump 10 and the delivery unit 20 are preferably connected to a common control, the control being designed such that both drive units 11, 21 can be controlled independently of one another. In particular, the speed of the first drive unit 11 and of the second drive unit 21 can be set independently of one another.

The control can comprise a regulation which, on the basis of predetermined parameters, brings about an automatic setting of the rotational speeds of the drive units 11, 21. For example, the speed of the first drive unit 11, which acts on the displacement pump 10, can be adjusted as a function of a temperature of the displacement pump 10 and / or a pressure of the medium to be conveyed at the pump outlet.

Likewise, the speed of the second drive unit 21, which acts on the screw 24, can be adjusted as a function of a pressure of the medium in the ejection area 16. It is preferably provided that the control or regulation of the system takes place mainly on the basis of the flow rate of the medium to be conveyed through the displacement pump 10. This is for process security. As part of a protective function, provision is preferably made for the power consumption of the second drive unit 21 of the delivery unit 20 to be used as a parameter for the control or regulation. The power consumption of the second drive unit serves as an indicator of an overload of the delivery unit.

As soon as a predetermined threshold value is exceeded, the system is switched off to protect against damage or at least the speed of the second drive unit 21 is reduced. To determine the aforementioned parameters, the system preferably has corresponding sensors that are connected to the control or regulation.

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

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

The sliding bearing sleeve 26 thus forms a guide and bearing for the worm 24. The sliding bearing sleeve 26 is exchangeable. For this purpose, two retaining rings 27 are provided, which are connected to one another via threaded rods 28 ( Fig. 4 ). The sliding bearing sleeve 26 is fixed in a clamping manner between the retaining rings 27. To change the plain bearing sleeve, only the threaded rods 28 are closed loosen so that the plain bearing sleeve 26 can be separated from the retaining rings 27. A new plain bearing sleeve 26 is then positioned between the retaining rings 27 and fixed by means of the threaded rods 28.

It is also possible for the sliding bearing sleeve 26 or, in general, a bearing for the screw 24 to be constructed 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 tensionable 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 delivery unit 20 and simplifies the replacement of the bearing. The above applies to all exemplary 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 conveyor unit 20 is constructed identically in the exemplary embodiments described here. However, there are differences in the shape of the ejection region 16.

In the embodiment according to Figs. 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 displacement pump 10. This is according to the side view Fig. 1 as well as in the plan view according to Fig. 2 good to see.

As in the Figures 3 and 4 As can be seen, the concentric cone 34 of the ejection region 16 is formed in one piece with a retaining ring 27. Thus, the concentric cone 34 can easily be exchanged analogously to the plain bearing sleeve 26. 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 shown in FIGS Fig. 5 and 6th is shown.

In general, the use of a conical ejection area 16 for conveying or transporting flowable medium is expedient. The asymmetrical cone 35 according to Fig. 5 and 6th has the additional advantage that in this way at least in the ejection area 16 and in the closed area 15 a straight inner bottom 29 is formed. This makes it easier to clean the delivery unit 20.

In detail is in the Fig. 5 and 6th It can be seen that the inner base 29 merges in a straight line into an inner circumferential surface of the positive displacement pump 10. In this respect, in the exemplary embodiment according to FIG Fig. 5 and 6th the medium to be conveyed is fed straight into the displacement pump 10. The axes of rotation of the screw 24 and the displacement pump 10 are offset from one another, but run parallel. The straight inner floor 29 is lowered in the open area 14, so that the lowest point of the entire system is located in the open area 14.

Provision is advantageously made for a cleaning opening 32 to be arranged in the open area 14. The cleaning opening 32 is thus arranged at the lowest point of the overall system, so that rinsing liquid that is introduced into the delivery unit 20 during cleaning can flow off automatically. This makes the cleaning process easier and faster. The device can therefore also be used well in hygienically sensitive areas.

A further exemplary embodiment which is particularly suitable for the transport or conveyance of solid or non-flowable media is shown Fig. 7 . The difference to the previously mentioned exemplary embodiments is that the ejection area 16 is formed by a plate 30. The plate 30 replaces the conical ejection region 16 of the previous exemplary embodiments. At the same time, the plate 30 forms a retaining ring 27 which fixes the plain bearing sleeve 26.

An outlet opening 31 is arranged centrally in the plate 30. 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 shown that the plate 30 supports a particularly uniform supply of media into the positive displacement pump 10 when the system is used to convey media that have a high internal shear resistance. In particular, these are solid or non-flowable media.

For all the exemplary embodiments, a full screw can also be used instead of the screw 24, which is designed as a hollow screw. It is also conceivable to provide the screw axially with shaft bearings on both sides, in order to achieve stable guidance of the screw 24. However, the design effort is increased. In addition, the shaft bearings on both sides interfere with the delivery path to the displacement pump 10.

Furthermore, it applies to all exemplary embodiments that the outlet opening 31 can be designed differently geometrically 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 opening 31 can have an oval cross-section, which is widespread in the inlet openings 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 circular inlet opening 31.

List of reference symbols

10

Positive displacement pump

11

First drive unit

12

Pump outlet

13

Connecting flange

14th

Open area

15th

Closed area

16

Ejection area

20th

Delivery unit

21st

Second drive unit

22nd

Connection flange

23

drive shaft

24

slug

25th

Feed opening

26th

Plain bearing sleeve

27

Retaining ring

28

Threaded rod

29

Interior floor

30th

plate

31

Outlet opening

32

Cleaning opening

33

Deflection Gear

34

Concentric cone

35

Asymmetrical cone

Claims (14)

1. System for conveying viscous media with a positive displacement pump (10) and a conveying unit (20), which is arranged in the direction of flow of the viscous medium before the positive displacement pump (10) and is fluidly connected to the positive displacement pump (10), whereby the positive displacement pump (10) and the conveying unit (20) have mutually independent drive units (11,21),
   characterized in that
   the positive displacement pump (10) and the delivery unit (20) are arranged in a line, so that a conveying direction of the conveying unit (20) is aligned coaxially with an axis of rotation of the positive displacement pump (10).
2. System according to claim 1,
   characterized in that
   that the positive displacement pump (10) has a first drive unit (11) and the delivery unit (20) has a second drive unit (21), whereby at least one rotational speed of the first drive unit (11) being adjustable independently of one rotational speed of the second drive unit (21).
3. System according to claims 1 or 2,
   characterized in that
   that the positive displacement pump (10) is an eccentric screw pump or a screw pump.
4. System according to one of the preceding claims,
   characterized in that
   that the delivery unit (20) has a tamping piston or a push floor or a screw conveyor.
5. System according to claims 4,
   characterized in that
   that the screw conveyor has at least one screw (24), whereby an axis of rotation of the screw (24) is arranged parallel to an axis of rotation of the positive displacement pump (10).
6. System according to claim 5,
   characterized in that
   that the screw (24) is designed as a full screw or as a hollow screw.
7. System according to one of the preceding claims,
   characterized in that
   that the conveyor unit (20) has a closed region (15), an open region (14) and an ejection region (16), whereby the closed region (15) is arranged between the open region (14) and the ejection region (16).
8. System according to claim 7,
   characterized in that
   that the closed region (15) has an exchangeable bearing.
9. System according to claim 7 or 8,
   characterized in that
   that the ejection region (16) becomes smaller in a conical way to an outlet opening (31).
10. System according to claim 7 or 8,
    characterized in that
    that the ejection region (16) is limited longitudinally and axially by a plate (30), which is aligned perpendicular to a longitudinal axis of the conveyor unit (20) and has an outlet opening (31).
11. System according to one of the preceding claims,
    characterized in that
    that the conveyor unit (20) has a completely straight inner bottom (29).
12. System according to claim 11,
    characterized in that
    that the conveyor unit (20) has a cleaning opening (32), that extends through the inner bottom (29).
13. Method for conveying a viscous medium with a system according to one of the preceding claims, whereby the medium is guided in a straight line from the delivery unit (20) into the positive displacement pump (10) and whereby the delivery unit (20) and the displacement pump (10) are independent of one another controlled or regulated.
14. Method according to claim 13,
    characterized in that
    that a rotational speed of the delivery unit (20) and/or the positive displacement pump (10) is regulated depending on a pressure of the medium within the positive displacement pump (10) and/or a temperature of the displacement pump (10).

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