EP1306141A2 - Method and device for cleaning pneumatic conveyor lines using a bypass pig - Google Patents

Abstract

The cleaning method uses a pneumatically-driven pig (1) displaced longitudinally along the feed line (2) and provided with peripheral cleaning tools (18), e.g.brushes, contacting the inside wall of the feed line, with the pressurised air discharged via openings (14,15) spaced in the longitudinal direction of the pig, for removal of solid material from the feed line wall. The ratio of the pig feed velocity to the feed air velocity is less than 1, the feed air velocity having an angular component. <??>An Independent claim for a device for cleaning a pneumatic feed line is also included.

Description

The invention relates to a method and an apparatus for cleaning pneumatic delivery lines with a bypass pig according to the generic term of claim 1.

In general, a bypass pig is a subspecies of the displacement or Conveying pigs for pigging solids in pipelines.

In the "Handbuch der Molchtechnik", Essen: Vulkan-Verlag, 2000 (Bernd Skerra (ed.) "Are such pigs for cleaning pipelines described.

A bypass pig is shown and described on page 164, in which as Propellant air is used which is tubular from behind Openings of the pig towards the front (in the direction of movement) is blown and through the nozzles arranged in the pig an air vortex on the The inner wall of the delivery line to be cleaned causes. In this airflow powders and granules are whirled in front of the pig.

The disadvantage of the known bypass pig is, however, that only air vortices are generated by nozzle-like, forward-facing openings, which at appropriately loaded pneumatic conveying lines do not become one Carry out cleaning of the inner wall. In the worst case, this leads to the fact that the pig is protruding radially inwards into the delivery line Adhesion is fixed and can no longer be moved. The newt described is not for cleaning pipelines with conveyance of granules in Flight promotion is suitable because its cleaning effect is insufficient and he is moving at an unsuitable speed. The one used Compressed air is not suitable, as it is in the delivery line for delivery Take the intended granules with you.

For the flight conveyance of granules in pneumatic conveying lines a conveying speed of the granulate of at least 25 m per second required. If this speed falls below, then moves the granulate is no longer in the flight promotion phase, settles and becomes pushed in front of the cleaning pig. This is what happens described clamping effect, especially on pipe switches and Flange connections.

With the arrangement of forward-facing nozzles, which the Only clean the pipe wall with air vortices, but it is not possible the conveying speed of the pig to, for example, about 2 m per Second and at the same time the conveying air speed to Cleaning and flight conveyance of the granules at 25 m per second observed.

The nozzles used for cleaning therefore ensure that the known one The pig is only traversed with a relatively low air throughput, which is what granules brought in front of him do not make it fly. Such a newt will So push the granulate to be conveyed in front of you and will soon be on wedge the corresponding pipe switches and flanges.

Brush pigs based on the bypass principle have also become known are suitable for cleaning pipes through which liquid flows. such Cleaning pigs have brush bodies on radially adjustable ones Sealing sleeves arranged.

Due to the liquid introduced under excess pressure, the Brush sleeves against the pipe wall, the brushes rub against it the inner wall of the pipe wall and thus lead to one Cleaning effect. However, water powered pigs are in pneumatic Delivery lines for conveying powder or granules cannot be used.

In particular, the use in pneumatic conveyor lines is therefore not given because the distribution ratio between pig speed and The brushing effect should be coordinated so that it is satisfactory Degree of cleaning of pipes and the pipe switches installed in them can be achieved.

The reason for the difficulty lies in the transfer of the excellent functioning pigging technology from the wet area with the for it necessary sealing sleeves in the pneumatic conveyor technology.

The invention is therefore based on the object, a method and one pig operated by the process, and a pig itself to further train that in pipelines carried by flight promotion Granules and dusts have a superior cleaning effect.

The object is by a method according to claims 1 and 11 and solved by a device according to claims 3 and 13. The procedure according to claim 1, characterized in that the ratio of Pig speed to conveying air speed c / v is less than 1. This means, the pig speed is compared to the conveying air speed reduced. The pig moves more slowly than the conveying air.

C is the pig speed, while v is the gas speed Conveying air is.

A preferred embodiment of the pig provides that a number of interchangeable brush disks arranged on the pig axis predetermined different bristle hardness are provided and that at least these brush disks to a significant extent from the conveying air are enforced.

The invention provides a pig, which according to the prior art known bypass pigs resembles, but is different by the same Conveying air volume moves like the previous bulk transport, whereby its moving speed of a predetermined c / v proportion corresponds and the resulting combination of flow and mechanical cleaning influence on the bulk good Performs wall cleaning of the pipeline.

According to the invention, it was recognized that a superior Cleaning effect with bypass pigs in pneumatic conveying lines only is reached when the pig at less than 25 m per second, e.g. 2 m per second, but the flow rate is nevertheless through the newt is in the range of 25 m per second, around which to enable conventional granulate transport as flight promotion.

The contradicting demands (on the one hand the relative reduced speed of the newt and on the other hand the high Flight conveyor speed of the granules) according to the invention solved that the bypass pig assigned relatively large bypass openings be, whereby part of the bypass air flows through the brushes themselves and a other part of the bypass air through in the axis of the cleaning pig arranged bypass holes, which in the assigned spaces penetrates between the brush discs and also the core of the pig axially interspersed.

According to the state of the art, pure brush pigs were always included Chained or pushed with bendable bars. This will be after the Invention avoided, and the invention proposes a free movement of which Conveying air driven bypass pig in a pneumatic delivery line in front.

This prevents the granules in front of the pig settles; it will therefore continue to receive funding in the form of flight promotion. The Granulate is therefore not displaced, but flies in front of the newt.

This removes the parts detached from the pipe wall by the brushes the pig accelerated, guided and at high speed moved away. With this new funding principle, superior Cleaning results achieved.

The invention is therefore not a displacement pig that cleans a "gun barrel" in the manner of a "cannon cleaner", but a bypass pig that moves at a slow speed and through which the conveying gas flows at high speed, so that this conveying gas flows in the direction of flight the granulate is transported away from the pig and cannot be deposited.
The brushes with their individually attached and essentially radially designed bristles have the advantage that, with appropriate elastic bending, they also graze along the corresponding edges of pipe switches, welded seams and flange connections and there also remove the adhering granules and convey them away in front of them.

Due to the significant airflow that blows through the brushes these are also kept free from buildup, are free to move and become cleaned.

In a preferred first embodiment of the invention, it is provided that that interchangeable or non-interchangeable on the pig axis fixed brush disks are arranged.

With fixed brush discs the advantage of a simple structure achieved.

Instead of filling the brush discs with individual bristles, you can also bristle-like functional features are used. For example lobe-like, trapezoidal, cylindrical or other shapes, in substantially radially outwardly directed bristles are used.

It is only important that a cleaning effect through elastic contact of corresponding tips of such bristles or rags on the inside of the tube is achieved. In addition, these elements should have a corresponding axial Allow air flow.

In a second embodiment of the invention it is provided that the pig axis in addition to several fixed brush disks rotatable brush disks are arranged.

No separate active rotary drive is assigned to these brush disks. she are only passively rotatable, e.g. B. because the bristles are arranged in a swirl and in the longitudinal conveyance of the bypass pig through the line itself Twist brush disks automatically and helically, making them one Clean the inside of the pipe.

In a further preferred embodiment it is even provided that some or more of these brush disks are also actively rotating. Such an active rotary drive takes place, for. B. via a turbine drive due to the conveying air flowing through.

These brush disks are equipped with guide vanes, and the air flow through these guide vanes leads to an active rotary drive of the respective Brush disc in the manner of a jet drive.

The types of brush disks mentioned at the beginning (rigid, passively rotatable and active rotary drives) can be a single one Form bypass pig, or a bypass pig can only consist of one or several of the above combinations can be put together.

In a further embodiment of the present invention, it is provided that that the pig axis is not necessarily rigid. It can also be articulated be trained.

The pig axis can thus also consist of several joints Pig axle sections exist, with some of the brush discs firmly on the axis is arranged, while again part of the brush discs is rotatably arranged on the pig axis and the rotation of the Brush discs through a turbine-like design with the help of the conveying air he follows. The direction of rotation of the brush discs can vary depending on the type of installation Pig axis (orientation to the conveying air) must be the same or opposite. The subject matter of the present invention does not only result from the subject of the individual claims, but also from the Combination of the individual claims.

As a further embodiment is a spherical brush pig provided that also works with an air flow so that the already o. a. Correlations come into play accordingly. The essential The difference to the form described so far is that the Air flow not directly through the body of the brush pig itself passes through, but between the inner wall of the delivery line and the Surface of the spherical brush pig, from which the individual Bristles protrude, as well as between the individual bristles themselves preferred application of the spherical brush pig is included Delivery pipes with relatively small diameters, for example 3D, 5D and the like.

By varying the spherical body in diameter, shape, length and Arrangement of the bristles and their elasticity can be the volume flow through the conveying air in relation to the conveying speed are achieved, whereby the ratio c / v <1 already reached here can be. This is the above. Method also with this embodiment possible.

All disclosed in the documentation, including the summary Information and features, especially those shown in the drawings spatial training, are claimed as essential to the invention, insofar as they individually or in combination are new compared to the prior art.

In the following, the invention is based on several ways of execution illustrative drawings explained in more detail. Here go from the Drawings and their description further features essential to the invention and advantages of the invention.

Figur 1:

Schnitt durch eine erste Ausführungsform eines Bürstenmolches mit feststehenden Bürstenscheiben,

Figur 2:

der Bürstenmolch nach Figur 1 in perspektivischer Darstellung,

Figur 3:

Stirnansicht auf die Anordnung in Figur 1,

Figur 4:

Schnitt durch eine zweite Ausführungsform eines Bürstenmolches mit drehbar angetriebenen Bürstenscheiben,

Figur 5:

Stirnansicht gemäss Pfeilrichtung V in Figur 4,

Figur 6:

Schnitt gemäss der Linie VI-VI in Figur 4.

Figur 7:

Draufsicht auf eine weitere Ausführungsform

Show it:

Figure 1:

Section through a first embodiment of a brush pig with fixed brush disks,

Figure 2:

1 in perspective representation,

Figure 3:

Front view of the arrangement in Figure 1,

Figure 4:

Section through a second embodiment of a brush pig with rotatably driven brush disks,

Figure 5:

Front view according to arrow direction V in FIG. 4,

Figure 6:

Section along the line VI-VI in Figure 4.

Figure 7:

Top view of another embodiment

FIGS. 1 and 2 show a first embodiment of a brush pig 1 shown, which consists of a fixed axis 8 on which a number of fixed brush discs 4,5,6,7 lying one behind the other and parallel are threaded to each other.

There are individual spacer disks 10 between the brush disks arranged, and the pig 1 has a front tip 11. The mutual distance between the brush discs can thus be chosen the length of the spacer 10 can be selected.

The axis 8 is at the rear end by a closure piece 9 closed, which essentially consists of two split washers 13th exists, which are held together by a clamping ring 12.

In this way it is prevented that the brush disks 4-7 together with the spacers 10 from the continuous axis 8 to the rear getting deported.

The closure piece 9 is very much due to the clamping ring 12 used easy to open and close.

Instead of the mounting method of the brush discs described here Of course, all other types of fastening are also possible.

For example, it can be provided that the axis 8 consists of a There is a threaded bolt which is connected at the front to the tip 11 and which its rear side instead of the closure piece 9 a corresponding Threaded nut, which also carries the brush disks 4-7 and holds the associated spacers 10 together.

It is of course also possible to pass through each individual brush disk 4 to fix a corresponding clamping device on an axis.

Likewise, the rear closure piece 9 can also be used as a clamping device be trained.

The brush pig 1 thus formed is conveyed in the direction of arrow 3 through the delivery line 2 promoted, each brush disk 4 according to Figure 3 from one Brush ring 18 is made with any number of radial outside bristles is occupied.

The bristles are held in a holding disc 19, which in turn is part of a Carrier disc 20 is, which is threaded on the axis 8.

The conveying air now flows through the pig in the direction of arrow 3, initially through a central center bore 14, which is air-tight in the area of Spacers 10 is opened by a number of bypass holes 15.

The air flows in the direction of arrow 16 through these bypass holes (Bypass air flow) into the spaces between the individual Brush disks 4 - 7 and clean these brush spaces from the From the inside and then flows axially through the respective brush disk Direction.

At the same time, another air flow flows as a direct air flow 17 in a straight line (axial) direction through the corresponding brush disks 4 - 7 and provides the desired conveying air speed of about 25 m per second the line in front of the brush pig 1. This turns the pipe in front of the pig Granules in the manner of a flight promotion moved and before settling in the Management preserved.

The newt therefore does not run the risk of stowing the granulate in front of it; on This prevents jamming in a granulate piled up in front of it.

The perspective view of a brush pig 1 with fixed Brush disks 4-7 are shown in Figure 2. It can be seen here that the Bypass air flow flows out of the bypass bores 15 16 and through the individual brush wreaths 18 goes through.

Furthermore, the direct air flow 17 is also shown, which is also the individual Brush wreaths 18 interspersed.

It can be seen that the granules 32 fly in front of the pig 1 and the Brush wreaths 18 have a superior cleaning effect on the inner wall unfold the delivery line 2.

Should it turn out that the brush pig 1 according to the invention flies fast, d. H. at a speed of e.g. B. more than 2 m per Second, then you can use the corresponding reduction inserts from the Center bore 14 are taken out to the flow in the Increase center axis in direction of arrow 3. This changes the c / v value.

The invention also sees in an embodiment not shown for example that some of the brush disks, e.g. B. the brush discs 5, 6, are arranged passively rotatable. This would be the respective brush wreath 18 have a helical contour and each of the brush disks 5, 6 passively twists in the manner with the longitudinal movement of the brush pig 1 a swirl movement in the pipeline.

It can also be provided that the two brush disks 5, 6 come together turn in opposite directions if a corresponding opposite Helical toothing in the outer area of the respective brush ring 18 is provided. For this purpose it can be provided that one Brush disc with its orientation towards the front and the same trained Brush disk 6 is installed with its orientation to the rear, so one generate opposing swirl movement.

Figure 4 shows as a further embodiment that it is also active rotationally driven brush disks 22, 23 on a brush pig 21 there.

With regard to the remaining parts, all explanations apply as well were given with reference to Figures 1-3.

In the exemplary embodiment according to FIG. 4, the middle brush disks 22, 23 turbine-like rotary drive. Each is a front, fixed Brush disk 24 (see Figure 5) and a rear fixed brush disk 7 provided between which the rotating brush discs 22, 23rd are arranged.

The front fixed brush disk 24 according to FIG Circumferentially distributed recesses 25 through which the direct air flows in the direction of arrow 3. The brush ring 19 is through corresponding spokes 26 supported against the axis 8. The Recesses 25 are intended to cause that of the nozzle-like Guide vanes 27 of the rotating driven brush disks 22, 23 flowing out Air in a large cross section can penetrate the front brush disk 24.

Each rotary brush disk 22, 23 is approximately according to FIG. 6 educated. There are radially inward the washer 19 obliquely staggered vanes 27, each forming a nozzle vane.

As soon as there is air in (perpendicular to the plane of the drawing according to Figure 6) through this Guide blade 27 flows through, an angular momentum, for example, in Direction of arrow 33 generated. The rotary bearing of each individual brush disc 22, 23 takes place here via needle bearing 28. The needle bearing consists of a fixed inner ring 29, the needles for storage and a rotating outer ring 30.

The turbine ring 31, which adjoins the needle bearing radially outwards includes the aforementioned vanes 27.

In this embodiment, too, it is possible to remove the brush disks 22, 23 in to incorporate the opposite orientation so that the one Brush disc for example in the direction of arrow 33 and the other Brush disk actively rotated in the opposite direction.

FIG. 7 shows a spherical embodiment of a brush pig 34 out. This embodiment effects a completely free movement the pipe system of the delivery lines 2. Bypass bores for the air flow through the brush pig 34 are not provided here because the conveying air between the inner wall of the delivery line and the surface of the spherical brush pig 34, from which the individual bristles 36 protrude, as well as between the individual bristles 36 themselves through strikes.

The bristles 36 are in turn elastic, so that they are in the the manner already described the inner wall of the conveyor line 2 clean. In the division and training, the bristles 36 are designed that sufficient air 38 can flow through between them, and on the other hand, a sufficient cleaning effect is achieved. To do this Clearances 35 are formed between the bristles 36 through which the air 38 flow along the individual paths 37 and the cleaned particles can carry with him.

A major advantage of this embodiment is that the spherical brush pig 34 always in bends and knee areas optimally touches the inner wall of the delivery lines 2 and thus also reliably cleans. This is particularly so because it is free in every direction is movable in the conveyor lines 2, making it particularly small Pipe diameters can be used in which others Embodiments already tend to jam or stick.

The bristles 36 themselves can be designed as individual bristles or also as bristle groups.

Drawing Legend

1

brush pig

2

delivery line

3

arrow

4

brush disc

5

"

6

"

7

"

8th

axis

9

Lock Piece

10

spacer

11

top

12

clamping ring

13

Shutter disk

14

center bore

15

bypass bore

16

Bypass airflow

17

Direct air flow

18

brush ring

19

retaining washer

20

carrying disc

21

brush pig

22

brush disc

23

"

24

brush disc

25

recess

26

spoke

27

vane

28

needle roller bearings

29

Inside-

30

outer ring

31

turbine ring

32

granules

33

arrow

34

brush pig

35

free space

36

bristles

37

paths

38

airflow

Claims (17)

Process for cleaning pneumatic conveying lines with a bypass pig, which is moved longitudinally in the conveying line driven by compressed air and cleans the inner wall of the conveying line with its cleaning tools arranged on the outer circumference, whereby the compressed air flows through the longitudinally arranged openings through the pig and in the direction of movement emerges from the front of the pig and removes and takes solids (e.g. granules) from the pipe wall, characterized in that the ratio of the pig speed to the conveying air speed c / v is less than 1, and that the conveying air speed is suitable for the granulate in the manner of a To promote flight promotion. A method according to claim 1, characterized in that the pig is conveyed at less than 25 m per second, for example 2 m per second, and that the flow rate through the pig is in the range of 25 m per second. Device for cleaning pneumatic conveying lines with a bypass pig, which moves longitudinally in the conveying line, driven by compressed air, and cleans the inner wall of the conveying line with its cleaning tools arranged on the outer circumference, whereby the compressed air flows through the longitudinally arranged openings through the pig and forwards in the direction of movement emerges from the pig and removes and takes away solids (eg granules) from the pipe wall, characterized in that the bypass pig (1) is assigned relatively large bypass openings (14, 15), and part of the compressed air by the cleaning tools (4- 7; 22-24) and another part of the compressed air flows through bypass bores (14) arranged in the axis of the pig. Device for carrying out the method according to one of claims 1 or 2 and / or according to claim 3, characterized in that exchangeable and / or non-exchangeable fixed cleaning tools are arranged on the axis (8) of the pig (1). Apparatus according to claim 4, characterized in that the cleaning tools are designed as brush disks (4-7; 22-24). Device according to one of claims 1 to 5, characterized in that the cleaning tools are designed as passively rotatable brush disks (5, 6). Device according to one of claims 1 to 6, characterized in that the cleaning tools are designed as actively rotating brush disks (22, 23). Device according to one of claims 1 to 7, characterized in that the axis (8) of the pig (1) is articulated. Device according to one of claims 1 to 8, characterized in that the direction of rotation of the cleaning tools (5,6; 22, 23) is the same. Device according to one of claims 1 to 9, characterized in that the direction of rotation of the cleaning tools (5,6; 22, 23) is in opposite directions. Method for cleaning pneumatic conveying lines with a bypass pig, which moves compressed air-driven longitudinally in the conveying line and cleans the inner wall of the conveying line with its cleaning tools arranged on the outer circumference, characterized in that the conveying air (38) between the inner wall of the conveying line and the Surface of the brush pig (34), from which the individual bristles (36) protrude, and between the individual bristles (36) themselves. A method for cleaning pneumatic conveying lines according to claim 11, characterized in that the ratio of pig speed to conveying air speed c / v is less than 1, and that the conveying air speed is suitable for moving the granulate in the manner of a flight conveyor. Device for cleaning pneumatic conveying lines with a bypass pig, which moves longitudinally in the conveying line driven by compressed air and with its cleaning tools arranged on the outer circumference, cleans the inner wall of the conveying line, characterized in that the brush pig (34) has bristles (36) on its surface. has, which protrude from it and are arranged on it that the conveying air (38) between the inner wall of the conveying line (2) and the surface of the brush pig (34), as well as between the individual bristles (36) themselves, so that the ratio of Pig speed to conveying air speed c / v is less than 1, and that the conveying air speed is suitable for moving the granulate in the manner of a flight conveyor. Device for cleaning pneumatic conveying lines according to claim 13, characterized in that the free spaces (35) between the bristles (36) are designed such that the conveying air (38) flows through them, along individual paths (37) and the cleaned particles carries with it. Device for cleaning pneumatic conveying lines according to claim 13 or 14, characterized in that the bristles (36) are designed as individual bristles. Device for cleaning pneumatic conveying lines according to one of claims 13 to 15, characterized in that the bristles (36) are designed as bristle groups. Device for cleaning pneumatic conveying lines according to one of claims 13 to 16, characterized in that the brush pig (34) is spherical.

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