EP1563745A1 - Rod making machine, method of operating the same, and air conveyor system - Google Patents

Abstract

Process for operating a strand machine (10) used in the tobacco-processing industry comprises sorting a tobacco flow (38) in a chamber (20) of the machine using a first air flow to remove the tobacco ribs (39). The sorted tobacco flow (38') passes through the first and/or a second air flow in the chamber. A third and a fourth air flow remove the air from the chamber. The sum of the air throughput of the third and fourth air flow is constant regardless of the product output of the machine. Independent claims are also included for: (1) Strand machine for the tobacco-processing industry; and (2) Air-conveying system for a strand machine.

Description

The invention relates to a method for operating a stranding machine the tobacco processing industry, by means of a first air stream a tobacco stream in a room of the strand machine is sighted so that tobacco stems from the tobacco stream be separated, wherein the sighted tobacco stream through the first and / or a second air flow is conveyed in the space, wherein a third and a fourth air flow are provided, the air out of the room. The invention further relates to a Strangmaschine the tobacco processing industry comprising a tobacco sifter, a Saugstrangförderer and a device for conveying tobacco to the suction belt conveyor, wherein the Device for conveying tobacco defines a space, wherein for sighting and conveying a stream of air in the room einbringbar is.

The invention finally relates to an air conveyor system for a Extrusion machine of the tobacco processing industry, comprising Recirculating fan and a Saugluftgebläse, by means of the circulating air blower Air is conveyed into a room into which a stream of tobacco in particular by the conveyed air, aussichtbar and is conveyable, and wherein the Saugluftgebläse connected to the room is, with air from the room is sucked.

A corresponding method, a corresponding stranding machine and a corresponding air conveying system is known from EP 0 727 156 A1 known. A corresponding stranding machine is from the Applicant sold under the name Protos 100.

In such a method, such a stranding machine and such an air conveyor system, however, the effect occurs that the rib discharge from the tobacco stream to be sighted with the production performance of the strand machine changes. For example in throttling production more tobacco which leads to a deterioration of the efficiency of the Procedure and the strand machine leads. This leads in the end to ensure that the corresponding manufactured cigarettes different Have properties.

In contrast, the invention is based on the object Method for operating a stranding machine, a stranding machine and an air conveying system for a rod making machine of the tobacco indicate the manufacturing industry by which it is possible to produce qualitatively uniform cigarette strands.

This problem is solved by a method for operating a Extrusion machine of the tobacco processing industry, by means of a first stream of air a tobacco stream in a space of the strand machine is sighted so that tobacco stems from the tobacco stream be separated, wherein the sighted tobacco stream through the first and / or a second air flow is conveyed in the space, wherein a third and a fourth air flow are provided, the air out of the space, that is further developed by that regardless of the production capacity of the stranding machine the Sum of the air flow of the third and fourth airflow in Is essentially constant.

In the context of the invention, the term production means especially the speed of one of the sighted Tobacco stream formed strand or a length of a cigarette rod per time unit. Within the scope of the invention is the space in particular a room in the strand machine, which has a rolling room, includes a fluidized bed room and a room in which a Tobacco stream is spotted. The tobacco sifter may be a cautious be. The tobacco sifter may also include a permissive.

Furthermore, in the context of the invention the term air flow means the delivery rate of air per unit time or subsidized Air volume per unit of time.

By holding the sum of the air flow of the third and fourth air flow to a substantially constant value, and regardless of the production output of the stranding machine, is it possible to influence the air pressure in the room in such a way that a uniform sighting of the tobacco stream is made possible. The lower the production capacity of the stranding machine, the better The suction belt of the suction belt conveyor, which seals in the Frame of the invention may also be a Saugbandförderer, by Applying tobacco, so that less air in the form of the third Air flow discharged from the room via the Saugstrangförderer becomes. Accordingly, then the promoted out of the room should Air flow can be increased in the form of the fourth air flow, so that the air speed at the sifter, comprising a caution and possibly a Nachsichter, not too changed and preferably remains constant, so that the rib discharge from the Tobacco flow also remains constant. This effect essentially occurs because of that, because the pressure in the room is essentially constant remains so that the air speed on the sifter does not change must become. The sum of the air flows of the third and the fourth air flow is automatic or with running strand machine kept constant.

If an air distributor is upstream of the room, taking out of the Air distributor air is drained into the environment is one particular given effective and easy way out of the Space funded by the fourth air flow out air flow to change. The first, second and fourth airflow are usually part of a recirculation system, by a circulating air blower is operated. In the event that air from the air distributor in the environment is drained, with the air distributor also Part of the air circulation system is and between the circulating air fan and the room is arranged, promotes the circulating air fan due the lower pressure difference between input and output one larger air volume; i.e. the air flow increases. hereby is automatically the extracted from the room air flow elevated.

The air distributor can also have an air line with a branch be. Furthermore, in the environment air from the air manifold over another air line to be drained. Preferably, the changed in the environment discharged air flow. If to Change of the deflated air flow a throttle in a discharge line of the air distributor is adjusted, is a special cost-effective implementation of the method possible. The In the context of the invention, the discharge line can also be an outlet line and in particular is a diffuser or ends in one Diffuser.

Preferably, a substantially constant pressure in the room set. The space here includes in particular the rolling space or fluidized bed space of the stranding machine.

Preferably, the pumped out of the room air flow the fourth air flow controlled or regulated. The control or regulation can be done continuously, so that too continuously changed the production capacity of the strand machine can be without affecting the quality of the produced cigarette rod would be impaired. For this example, the air pressure measured in the room and preferably in the area of the classifier or in the rolling room. If the control happens step by step, for example, by specifiable positions of the throttle valve is a particularly cost-effective process management possible.

The object is further by a rod maker of the tobacco processing industry comprising a tobacco sifter, a Saugstrangförderer and a device for conveying tobacco to dissolved the Saugstrangförderer, wherein the means for conveying of tobacco defines a room, where to sift and to Promote an airflow is introduced into the room, being independent from the production output of the stranding machine of the Space taken out air flow substantially constant is. This happens according to the invention automatically or at running machine.

In the context of the invention, the term includes the device for Conveying tobacco means for conveying and / or directing a Air flow or multiple air streams, by means of the tobacco movable is. Further, the means for conveying tobacco comprises, for example also fall shafts, a fluidized bed and other means in a rod maker of the tobacco processing industry.

Preferably, an air distributor in the conveying direction of the air flow arranged upstream of the room, the air distributor has an outlet in the environment. This is a special accurate air flow promotion possible in the stranding machine. When the air flow rate that can be discharged into the environment is changeable is realized is a particularly effective and easy way a uniform tobacco rod even with different To realize production services of the stranding machine. A Particularly cost-effective implementation is provided by that a throttle valve is provided in the outlet.

Preferably, a pressure sensor is provided in the room. through of the pressure sensor, it is easily possible to use a controller or Control of the airflow which can be discharged into the environment realize. For this purpose, the pressure sensor is preferably in the region of Classifier arranged or in the rolling room of the fluidized bed. To the Control or regulate the airflow that can be discharged into the environment a control or regulating device is provided. In a particularly preferred embodiment of the invention is the Control or regulation continuously allows. This is it possible, also continuously the production capacity of the stranding machine change without compromising the quality of the cigarette rod suffer from. If the control or regulation is gradual allows predetermined production outputs can be set in any case, those in these production services resulting cigarette lines have a good quality.

Between the corresponding production achievements one can Interpolation take place, which also makes a correspondingly good Quality of the cigarette rod for non-specified production is possible. Preferably, at least two Throttle valve positions can be specified. This is a special simple and cost-effective realization of the stranding machine given, especially in operation usually two different production services in cigarette production or cigarette rod production to be used by cigarette manufacturers.

The object is further by a rod maker of the tobacco processing industry, comprising a tobacco sifter, a Saugstrangförderer and means for conveying Tobacco to the Saugstrangförderer, the means for Promoting tobacco defines a space, being for sifting and for conveying an air flow into the room can be introduced, wherein upstream of the room, with respect to the conveying direction of the Air flow at least a portion of the air flow into the environment is deliverable, the air flow, which can be discharged into the environment is, depending on the production capacity of the stranding machine is. This makes it possible in a simple way that the out of the room through a recirculation system outfeed air flow depending on the production output of the stranding machine is changeable, so that in the room is essentially a constant Pressure can be achieved and so that the tobacco sifter a Air flow of a substantially constant speed Has available.

Preferably, the deliverable in the environment air flow is at lower production capacity can be increased. A special Effective embodiment of the strand machine according to the invention then given when an air distributor in the conveying direction of the air flow is arranged upstream of the room, wherein the Air manifold has an outlet in the environment. An inexpensive Solution is given when to change in the Environment deliverable air flow provided a throttle is.

The invention is finally achieved by an air conveyor system for a Strand machine of the tobacco processing industry comprising a Circulating air fan and a Saugluftgebläse solved, by means of the Recirculation blower air is conveyed into a room, in which a Tobacco stream, in particular by the conveyed air, aussichtbar and is conveyable, and wherein the suction fan with the room is connected, wherein air is sucked out of the room, wherein regardless of the production output of the stranding machine Essentially, air flow that can be conveyed out of the room is constant.

Preferably, downstream of the recirculation fan and upstream arranged an air distributor of the room. If the constant of the air flow which can be conveyed out of the room by venting air upstream of the room, is a particularly effective air flow in the air conveyor system allows. It is expedient a throttle in a the air Provide in the environment draining line. Preferably is a substantially constant pressure in the room adjustable. For this purpose, for example, a pressure sensor in the room is used. If a control device for controlling or regulating the in the environment drained air flow is provided, can very effectively the task is solved. The control or regulation is preferably continuous or incremental, in the latter alternative, preferably two Positions or three positions of the throttle are provided or two or three predeterminable air flow rates can be specified.

Fig. 1

eine schematische Darstellung einer Strangmaschine in einer erfindungsgemäßen Ausführungsform, und

Fig. 2

eine schematische Darstellung eines erfindungsgemäßen Luftsystems einer Strangmaschine.

The invention will be described below without limiting the general inventive idea by means of embodiments with reference to the drawings. With respect to all details of the invention not explained in detail, reference is expressly made to the drawings. Show it:

Fig. 1

a schematic representation of a stranding machine in an embodiment of the invention, and

Fig. 2

a schematic representation of an air system according to the invention a strand machine.

Fig. 1 shows schematically a strand machine according to the invention 10. In the stranding machine 10, some elements are dashed shown in the following.

Tobacco is made from a tobacco stock by means of a steep wall conveyor 11 promoted to a stowage 12. From the stowage 12 Tobacco by means of a removal roller 13 and a racket roller 14 taken and essentially isolated in a manhole 15 delivered. In the shaft 15, a down forms directed tobacco stream 38.

The tobacco stream 38 enters the area of a classifier and in particular first in the area of a cautionary 16, in which by means of an air flow from an air flow line 32 _1, the tobacco stream 38 is pre-sighted, such that the light tobacco stream components are conveyed in the direction of a fluidized bed 18 and the Heavy tobacco stream components, mainly tobacco ribs, fall through down. The downwardly falling tobacco stream constituents are rearranged in a Nachsichter 17. The sifting of tobacco is known per se, so that the sizing itself will not be discussed further here.

By means of the air flow, which is given from an airflow line 32 _{2 of} the Nachsichters on the tobacco stream 38 'and by means of the air flow from the cautery 16 the sighted tobacco stream 38' reaches the fluidized bed 18, in which through further air flow lines 32 ₃ air streams through corresponding nozzles, For example, Coanda nozzles, the sighted tobacco stream 38 'is further promoted in the direction of Saugstrangförderer 19.

The exposed ribs pass over the rib shaft 25 in Direction of a Schüttelrinne 26, from the smaller tobacco components be shaken out so that essentially just ribs be dissipated.

In the strand machine according to the invention some air flow lines 32 ₁ , 32 ₂ , 32 ₃ , 32 ₄ , 32 ₅ , 32 ₆ , 32 ₇ , 32 ₈ , 32 ₉ , 32 ₁₀ , 32 ₁₁ and 32 _{12 are} provided to promote the corresponding air streams ,

There is a recirculation system 44 is provided which comprises a circulating air fan 24. The circulating air blower 24 conveys or regulates compressed air via a throttle valve 23 into an air distributor 21, from which compressed air is passed via a throttle valve 22 to the warden 16. Further, the air manifold 21 directs compressed air to the indenter 17 and via other lines 32 ₃ to the nozzles in the fluidized bed 18. The air is then removed from the rolling chamber 20 via an air line 32 ₄ to a Entstaubungszyklon which separates the air from air-borne tobacco dust , Another part is supplied via lines 32 ₅ the air circuit of Saugstrangförderer blower.

Part of the corresponding air flow or air flow is controlled or regulated by the throttle valve 23 again Convection fan 24 supplied. Furthermore, an air flow from the Rolling 20 discharged by means of the Saugstrangförderers 19 and two throttle valves 28 and 29 a Saugstrangförderer blower 27 supplied. The throttle valve 28 serves to Suction air is shut off when the suction belt conveyor is raised. The Throttle 29 is used to control the air flow of the Saugstrangförderer blower 27 to reduce at standing strand machine.

Further, the Saugstrangförderer blower 27 draws air from the environment via another line 32 ₆ , which opens between the throttle valve 29 and the Saugstrangförderer blower 27. From the Saugstrangförderer blower 27 compressed air is blown to the air center, wherein the throttle valve 31 is provided for adjusting the negative pressure in the Saugstrangförderer and the throttle valve 30 sets a pressure-free transition, such that the extracted air from the center air is slightly larger than that of the machine discharged air volume. As a result, the pressure fluctuations of the central dedusting be compensated and the resulting heat from the machine at least partially dissipated. Finally, a further pressure line 32 _{7 leads} from the vibrating channel 26 into the discharge line from the suction-strand conveyor-fan 27, so that there is also entrained an air flow.

With decreasing production capacity, it is now at strand machines of the prior art or in corresponding methods for Operation of a stranding machine of the tobacco processing industry come to that with falling production output of the rib discharge or tobacco discharge or the percentage rib discharge has increased. It has been recognized that when falling Production output the rising rolling pressure or the rising Pressure in the area around the sifter, the cautious 16 and the Nachsichter 17, throttling on the respective Classifier 16 and 17 affects, so that the rib amount or the strained amount of ribs or amount of tobacco increases.

It has now been found according to the invention that by keeping constant the sum of the from the rolling room or from the Sichterraum promoted air flow the percentage rib discharge or the percentage tobacco output can be kept constant, even with reduced production capacity. This happens for example, according to the embodiment of FIG. 1 by automatic adjustment of the throttle valve 34, through the one corresponding air flow through a line 32 'to a Diffuser 35 is guided, whereby a corresponding air flow discharged into the environment.

The automatic adjustment of the throttle valve 34 for the diffuser 35 may preferably be done by a compressed air cylinder. For this purpose, in particular two positions, in particular with precisely adjustable stops when two production outputs find the machine use. For example, the Production services 10,000 cigarettes per minute and 6,000 respectively 4,000 cigarettes per minute are used. At reduced Production output will be an increased air flow from the Rolling room sucked through the circulating air fan 24, which thereby is achieved that a larger air flow from the air manifold 21 is discharged via the line 32 'in the environment. By the discharge of compressed air through the diffuser or the conduit 32 'in the environment is a smaller pressure difference between the Input and output of the circulating air fan, so that the air flow is increased by the circulating fan, eventually causes the air flow of the discharged from the rolling room Air flow is increased, resulting in reduced air flow with reduced production through the suction belt conveyor essentially compensated.

The production capacity of the strand machines, for example throttled when the between the stranding machine and a corresponding storage machine is full memory. In this respect, it comes in the production of cigarettes and the subsequent Packing actually also provides that machine performance or production capacity must be throttled. This can happen, for example, when the packaging machine comes to a standstill and the stranding machine still working properly.

In Fig. 2 is a schematic representation of the air system of a inventive stranding machine in a further embodiment shown. Compressed air is via the circulating air fan 24 to the Air distributor 21 out. For this purpose, an air flow 320 is provided. From the air distributor 21 is a via a throttle 45th controllable or adjustable airflow 321 led to the caution. In the air distributor 21, for example, prevails a pressure of in Range between 10 and 80 mbar. Further, an air flow 322 becomes too a Nachsichterdüse out of the air manifold 21. Furthermore is an air stream 323, which is divided into three air streams, to the Fluid bed nozzles brought.

In the area of the caution, air streams 326, 327 also escape the atmosphere into the rolling room. The air distributor 21 leads also an airflow 337 for rib suction. The corresponding discharged ribs get to earth gravity and an air stream 336 in a vibrating trough 26 and then over spent an airflow 332 to the ribbed bearing 37. By the out the air distributor 21 to the defaulter guided airflow 322nd also creates a 335 air flow from the atmosphere, which in one Airflow 324 passes. In addition, from the rolling room 36 arrives an air flow 330 to the Entustaubungszyklon 33, from the one Air flow 334, which is controllable or controllable with a throttle flap, is returned to the circulating air fan 24 again.

The air distributor 21 also leaves a flow of air 325 over the Throttle 34 is controlled or regulated, from. This airflow 325 ends in a diffuser 35 and then in the ambient air. about the air flow 325 is from the Wälzraum 36 via the air flow 330 conveyed air flow controlled or regulated. By doing Embodiment of Fig. 2 takes place a control. One In this case, the control parameter is the rolling room pressure, which by means of a pressure sensor 42 whose signal via a measuring line 41 a control or regulating device 40 is supplied, measured becomes.

The control device 40 controls or regulates via a Control line 43, the throttle valve 34. It can be a continuous Control take place, as this is indicated in Fig. 2 or from another point of the machine production in the control or regulating device 40 are controlled, so that a corresponding control of the position of the throttle valve 34th is possible. The rolling room pressure changes due to the fact because at different production capacities of the stranding machine the discharged from the rolling chamber 36 airflow 340 its throughput changes, since the suction power of the Saugstrangförderers 19 itself with stranding machine also reducing production output reduced.

Due to the suction of tobacco or the negative pressure in the Saugstrangförderer 19 is also an air stream 328 located, the comes from the atmosphere. The pressure in the Saugstrangförderer is in the range of -80 mbar. From the Saugstrangförderer is a Air flow 329 led to the Saugluftgebläse. The suction fan or Saugstrangförderer blower 27 operates at a power of 7.5 kW and leads to an air flow in the air flow 333 Headquarters, both in production and at a standstill in the has a substantial constant air flow. Correspondingly leads yet another air flow from the ribbed bearing 37 to the center.

Further, an air flow 338 is provided to dust on a To introduce return conveyor into the system. From the dump gear another air flow 339 arrives at the suction belt conveyor fan 27. The air circulation system and the suction air system are over the air streams 331 connected to each other.

The circulating air fan operates at a power of approximately 5.5 kW. The fluidized bed space has approximately a pressure of 0 mbar. A Control of the throttle valve 34 for the so-called diffuser air 325 with two or more discrete positions represents a very simple and inexpensive solution. A regulation of Position of the throttle valve 34 to a constant rolling space pressure leads to a consistency of the function of the classifier in all production services.

LIST OF REFERENCE NUMBERS

10

rod machine

11

Steep wall conveyor

12

accumulating shaft

13

out roller

14

Beater roller

15

shaft

16

preliminary separator

17

sifter

18

fluidized bed

19

suction rod

20

Wälzraum

21

air distributor

22

throttle

23

throttle

24

circulation fan

25

rib shaft

26

vibrating conveyor

27

Suction rod blower

28

throttle

29

throttle

30

throttle

31

throttle

32 ₁ - 32 ₁₂

Air flow line

32 '

drain line

33

dedusting

34

throttle

35

diffuser

36

Fluidized bed space

37

ribs camp

38

tobacco stream

38 '

faced tobacco stream

39

tobacco stems

40

Control or regulating device

41

Measurement line

42

pressure sensor

43

control line

44

Forced air duct system

45

throttle

320 - 340

airflow

Claims (26)

Method for operating an extrusion machine (10) of the tobacco-processing industry, wherein a tobacco stream (38) is spotted in a space (20, 36) of the stranding machine (10) by means of a first air flow (321, 322), so that tobacco ribs (39) separated from the tobacco stream (38), wherein the sighted tobacco stream (38 ') is conveyed through the first and / or a second air stream (321, 322, 323) in the space (20, 36), wherein a third one (340) and a fourth (330) air stream is provided to convey the air out of the space (20, 36), characterized in that, regardless of the production output of the stranding machine (10), the sum of the air flow rates of the third (340) and fourth (330) air streams is essentially constant. A method according to claim 1, characterized in that an air distributor (21) the space (20, 36) is connected upstream, wherein from the air distributor (21) air (325) is discharged into the environment (35). A method according to claim 2, characterized in that in the environment (35) discharged air flow rate (325) is changed. A method according to claim 3, characterized in that for changing the discharged air flow rate (325), a throttle valve (34) in a discharge line (32 ') of the air distributor (21) is adjusted. Method according to one or more of claims 1 to 4, characterized in that a substantially constant pressure in the space (20, 36) is set. Method according to one or more of Claims 1 to 5, characterized in that the air flow rate of the third airflow (330) conveyed out of the space (20, 36) is controlled or regulated. A method according to claim 6, characterized in that the control or regulation is done continuously. A method according to claim 6, characterized in that the control is done step by step. A tobacco processing machine extrusion machine (10) comprising a tobacco sifter (16, 17), a suction belt conveyor (19) and means (18, 32 ₁ - 32 ₁₂ , 36, 321, 322, 323, 340) for conveying tobacco (38 38, 38 ') to the suction belt conveyor (19), the means (18, 32 ₁ -32 ₁₂ , 36, 321-323, 340) for conveying tobacco (38, 38') defining a space (20, 36), wherein an air stream (321-323) can be introduced into the space for sifting and conveying, characterized in that, independently of the production output of the stranding machine (10), the air flow rate taken from the space (20, 36) is substantially constant. Extrusion machine according to claim 9, characterized in that an air distributor (21) in the conveying direction of the air flow (321-323) upstream of the space (20, 36) is arranged, wherein the air distributor (21) has an outlet (32 ', 35) in the Environment. Extrusion machine according to claim 10, characterized in that the air flow rate which can be discharged into the environment can be changed. Rope machine according to claim 10 or 11, characterized in that a throttle valve (34) in the outlet (32 ', 35) is provided. Extrusion machine according to one or more of claims 9 to 12, characterized in that a pressure sensor (42) in the space (20, 36) is provided. Extrusion machine according to one or more of claims 9 to 13, characterized in that a control or regulating device (40) is provided for controlling or regulating the air flow rate which can be discharged into the environment. Extrusion machine according to claim 14, characterized in that the control or regulation is continuously enabled. Extrusion machine according to one or more of claims 12 to 14, characterized in that the control or regulation is made possible step by step. An extrusion machine of the tobacco processing industry, comprising a tobacco sifter (16, 17), a suction belt conveyor (19) and means (18, 32 ₁ -32 ₁₂ , 36, 321, 322, 323, 340) for conveying tobacco (38, 38 ') to the suction belt conveyor, said means (18, 32 ₁ -32 ₁₂ , 36, 321-323, 340) for conveying tobacco (38, 38') defining a space (20, 36), wherein for sifting and for Conveying an air flow (321-323) into the space can be introduced, characterized in that upstream of the space (20, 36) with respect to the conveying direction of the air flow (321-323) at least a part of the air flow (321-323) in the Environment is deliverable, wherein the air flow, which can be discharged into the environment, depending on the production capacity of the strand machine (10) is variable. Extrusion machine according to claim 17, characterized in that the air flow rate which can be released into the environment can be increased with lower production output. Extrusion machine according to claim 17 or 18, characterized in that an air distributor (21) in the conveying direction of the air flow (321-323) upstream of the space (20, 36) is arranged, wherein the air distributor (21) has an outlet (32 ', 35) into the environment. Extrusion machine according to one or more of claims 17 to 19, characterized in that a throttle flap (34) is provided for changing the air flow rate which can be released into the environment. Air conveying system for an extrusion machine (10) of the tobacco processing industry, comprising a circulating air blower (24) and a suction air blower (27), wherein by means of the circulating air blower (24) air can be conveyed into a space (20, 36) in which a tobacco stream (38 , 38 '), in particular by the conveyed air, is visible and conveyed, and wherein the Saugluftgebläse (27) with the space (20, 36) is connected, wherein air (340) is sucked out of the room, characterized in that independently from the production output of the stranding machine (10) of the out of the space (20, 36) can be conveyed out flowable air flow is substantially constant. An air conveyor system according to claim 21, characterized in that downstream of the circulating air blower (24) and upstream of the space (20, 36) an air distributor (21) is arranged. An air conveyor system according to claim 21 or 22, characterized in that keeping the air flow rate which can be conveyed out of the space (20, 36) is kept constant by discharging air (325) upstream of the space (20, 36). An air conveyor system according to claim 22 or 23, characterized in that a throttle valve (34) is provided in a conduit (32 ') discharging the air (325) into the environment. Air conveying system according to one or more of claims 21 to 24, characterized in that a substantially constant pressure in the space (20, 36) is adjustable. An air conveyor system according to one or more of claims 21 to 25, characterized in that a control or regulating device (40) is provided for controlling or regulating the air flow discharged into the environment.

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