WO1997019286A2

WO1997019286A2 - Pipe bend for feed pipes for feeding liquids or gases which may possibly be laden with solids

Info

Publication number: WO1997019286A2
Application number: PCT/DE1996/002166
Authority: WO
Inventors: Mehmet Yavuz Dedegil; Manfred Weber
Original assignee: Mehmet Yavuz Dedegil; Manfred Weber
Priority date: 1995-11-20
Filing date: 1996-11-14
Publication date: 1997-05-29
Also published as: EP0862711A2; AU1765697A; WO1997019286A3

Abstract

The invention concerns a pipe bend for feed pipes for feeding liquids or gases which may possibly be laden with solids. According to the invention, there is provided a preferably straight centre bend segment (2) of which the outer internal wall generating line meets with the outer internal wall generating line of an outlet bend segment (3) on the pipe bend exterior at a point (S) which forms the point of intersection between the imaginary extension of the inner internal wall generating line of an inlet bend segment (1) and the outer internal wall generating line of the outlet bend segment (3).

Description

Pipe elbow for conveyor lines for the conveyance of liquids or gases which may be contaminated with solids

DESCRIPTION

The invention relates to a pipe bend for pipes for the pneumatic transport of bulk goods, and generally for the passage of gases and any solids-laden liquids.

In such pipelines, the elbows wear considerably faster than the straight pipe sections because the solid particles have a higher inertia due to their higher density and cannot follow the gas or the liquid quickly enough when changing direction. They hit the manifold wall on the outside of the pipe bend and cause greater material removal, i.e. Wear.

The local wear rate depends, among other things, on the impact angle, the speed and the number of particles that strike a surface element of the inner wall per unit of time.

If a solid-fluid flow is deflected by a continuous, generally circular, curved elbow, the particles entering the elbow at different points in the cross-section hit the wall of the elbow at a different angle The outside of the manifold. As a result, the inner wall where the impact takes place at a particularly unfavorable angle wears out considerably more quickly than at other points on this bend.

As soon as the manifold wall becomes so thin in one place that it can no longer withstand the internal pressure, the wall is broken and the manifold becomes unusable.

Attempts have already been made to increase the service life of the elbow using a special shape. These developments are essentially shown in [1]. The most important and simplest measure seems to be the choice of a large radius of curvature; However, because of the space available, this radius cannot be chosen to be as large as desired. As a further measure, it has been proposed, for example, to design the circular bend with a square cross section so that the particle collisions are distributed over a larger area. The necessary transitions from circular to square cross section and vice versa, however, cause too much effort. Another type of deflection was achieved by means of a T-piece, where the nozzle was closed against the flow with a blind flange and the flow was passed on through the lateral nozzle. The filler neck should fill with the pumped solid and thus protect against wear. The disadvantage of this type of deflection is, on the one hand, the significantly higher pressure loss and, on the other hand, that it cannot be installed in all positions, as is the case, for example, with deflections from one direction vertically upwards to a horizontal direction. Finally, the filling in the blind socket can come loose and fall back into the line, which represents a risk of clogging. The Vortice-Ell manifold [2] represents a further development of this form of deflection. Instead of the T-piece with blind spigot, the blind spigot is closed with a spatially rounded rear wall and the flow is deflected starting at a favorable angle. The rotational flow generated in the dead space is intended to prevent solid particles from hitting the opposite wall, but this is not always possible; in addition, it can be observed that the vortex in this space also provides additional wear. The shape of these elbows is quite complex, their mass is large and they can practically only be produced as castings.

In many cases, the pressure loss of the Vortice-Ell bend is considerably higher than that of a circular bend and the service life extension achieved is relatively modest.

In EP 0 111 589 A1, a similar elbow is presented which shows a bulge on the outside of the arc and whose geometry is no less complicated than that of the Vortice-Ell elbow. It can be recognized as an advantage that the impact surface is reinforced in the material thickness, but its positive effect is partially compensated for by the less favorable impact angle. In contrast, the gamma manifold shown in [1] is geometrically simpler and lighter; moreover, it does not cause a greater pressure loss than the circular elbow. The counter wall is designed as a plane, which results in a constant angle of impact and results in better wear distribution on this flat wall. Due to the geometric concept, however, the angle of incidence is very steep and therefore very unfavorable in terms of wear. Both the Vortice-Ell, Both the gamma manifold and the manifold according to EP 0 111 589 AI have the disadvantage in common that they offer the solid particles a dead space. However, this cannot always be tolerated because, for example, there are chemical and / or biological-hygienic reasons.

The object of the present invention is to provide a pipe bend of the type mentioned at the outset which is distinguished on the one hand by extremely low wear and tear and which is geometrically simple and has no dead space, is economical and easy to produce in terms of material expenditure and moreover no longer Space takes up than a conventional circular elbow.

This task is carried out by the im

Claim 1 specified construction solved,

Further developments and special configurations of the pipe bend according to the invention are the subject of the subclaims.

A special training consists in the fact that the wear protection measures defined in the subclaims can also be used in connection with curved pipe elbows in the manner according to the invention.

The invention is explained below with reference to the drawing. This shows in

Figure 1 shows a first and a second embodiment of a pipe bend.

Figure 2 shows a third and a fourth embodiment of a pipe bend.

3 shows a representation relating to the manufacture of the pipe bend according to FIGS. 1 and 2 with regard to the required pipe cuts;

Fig. 4 shows a fifth and a sixth

Embodiment of a pipe bend;

5 shows a seventh and an eighth exemplary embodiment of a pipe bend;

6 shows a ninth and a tenth exemplary embodiment of a pipe bend, as well as various exemplary embodiments for the wear protection measures;

7 shows a first exemplary embodiment with regard to exchangeable wear protection means;

8 shows a second exemplary embodiment with regard to exchangeable wear protection means;

9 shows an eleventh embodiment of a pipe elbow; 10 shows a curved pipe bend with various exemplary embodiments of the wear protection inserts.

The elbow according to the present invention ensures that a constant angle w is always guaranteed between the direction of approach and the impact surface, in contrast to the known circular elbow, (FIG. 1A). The wear is thus largely evenly distributed over the middle manifold segment 2. This fact alone prolongs the service life of the pipe bend, because a "worst point" at which a hole generally arises no longer exists. The wear load of this point is now distributed over a much larger area. It is precisely here that the present invention differs from the manifolds consisting of segments, as described for example in DE 39 01 618 AI, and from the manifold with segment inserts made of wear-resistant material according to DE 35 30 987 C1. In the last two publications, a large number of segment elements were used to simulate an elbow, with the disadvantage of changing the angle of impact.

The individual elbow segments of the pipe elbows shown in FIGS. 1 and 2 can be cut out of a straight piece of pipe and, depending on the material, can be joined together by welding, gluing, soldering or in another suitable way (see FIG. 3). It is important to choose the cutting angle OC (Fig. 2B and Fig. 3) half as large as it corresponds to the deflection angle &"intended for this cut, since an elliptical ring surface with variable thickness (Fig. 3C) only by adhering to regulation 6 ~ = Oc / 2 that when assembling the pipe pieces to form an elbow (FIGS. 3D, E, F), the surface elements of the same thickness always face each other and no steps arise. (Compare also the angle constellation | ^ / t according to FIG. 2 for the transition from the middle elbow segment 2 to the outlet elbow segment 3).

With suitable pipe materials, the pipe elbows can also be produced by bending (Fig. 4A, B).

For often used redirections, i.e. for larger quantities, such as 90 °, 45 ° etc., the pipe elbows can also be made, depending on the material, by casting, drawing or bending (Fig. 4A, B). In particular, the prefabricated elbows can be manufactured at one or both ends with suitable connecting elements such as flanges, threads, welding sockets, etc. (FIGS. 5A, B). The pipe elbow consisting of straight sections offers the possibility of using additional elements to reduce wear on the elbow wall. Already the attachment of a round rod - see reference numeral 6 - on the outer surface line of the middle elbow segment (FIG. 6C, top) results in an extension of the tool life by approx. 60%. From a fluidic point of view, it is advisable to round off or bevel the edge of such a rod 6 on the entry side (FIG. 6A). This rod 6 can also have a rectangular cross section (FIG. 6C, middle) or an oval deformed round rod (FIG. 6C, below). As long as the cross section of such a rod 6 is not more than 20% of the inner tube cross section, no or no appreciable increase in the pressure loss is found.

Depending on the grain size of the conveyed particles, the rods 6 can also have a certain distance from one another, so that a small amount of the fine partly fix and can also act as wear protection; the mass of the insert rods is reduced. Other inserts 8 (FIG. 6G) made of more wear-resistant material can also be accommodated in the spaces between these (spaced-apart) rods 7, which take over the actual wear protection, the elements firmly connected to the elbow 7 perform the function of a holder.

In order to secure this function and make it independent of the position, the holding rods 7 and the inserts 8 can be provided with matching profiles. The inserts can also protrude above the holding rods 7 (FIG. 6G). The inserts 8 are to be exchanged at certain time intervals, so that only these inserts are lost and the manifold itself is reused.

It is a little more complex, but more effective, to arrange several rods next to each other on the outer surface line of the middle manifold segment, so that they cover about a quarter of the circumference, but without taking up more than 20% of the cross-section (Fig. 6D). Instead of bars lying next to one another, a circular segment (FIG. 6E) or a shell-shaped insert can also be used, which can be produced, for example, from a tube or round bar divided in the longitudinal direction (FIG. 6F).

The circular rods or wear shells to be used in particular in the middle elbow segment can be designed as complete inserts for subsequent installation or replacement, as shown in FIGS. 7 and 8. According to the invention, a wear protection insert consists of three Main parts, namely a retaining disk 11 or a retaining ring 12, a spacer 13 and a wear comb 14 or a wear shell 15.

The holding disc 11 (FIG. 7) is primarily suitable for installation between two flanges (FIG. 7D). Seals 19 must be provided on both sides of the disk. The retaining washer itself can also carry a seal, for example an O-ring in a groove or a glued-on flat seal. The washer 11 can be centered on the inner wall by the flange screws from the outside or with centering tongues 18. The centering tongues 18 are small leaflets which little obstruct the flow, but can fall off over time due to wear. If this is absolutely undesirable, the centering must take place from the outside, on the screws or by means of centering tongues pulled outwards, on the outer flange edge.

The holding disc carries the spacer 13 on its inner edge, for which purpose an inwardly projecting tongue can also be provided.

The retaining ring 12 (FIG. 8), on the other hand, is primarily intended for installation in bends that are installed using screw connections or sleeves. The thin ring, which extends to about half of the inner circumference, has the task of securing the direction. The spacer 13 is attached to it. The retaining ring 12 and the spacer 13 are attached to the manifold by, for example, one or more screw (s), pin (s), etc.

If an exact direction is not necessary, the retaining ring 12 or the 10

Retaining washer 11 is dispensed with and the spacer is fastened directly to the intake manifold segment 1 by screws, pins, spot welding or in another suitable manner.

The spacer 13, which carries the actual wear protection elements, comb or shell, at the lower end, should protrude slightly beyond the holding disc or the holding ring against the flow direction in order to deflect the incoming particles as deflectors and thus protect the fastening point against wear. Furthermore, the fastening between the retaining disk or the retaining ring and the spacer should be designed such that the spacer, which is somewhat oversized in length, can be displaced in the longitudinal direction. This measure allows a wear insert in the form of a modular system to be adapted to various segment elbows. The connection between the spacer and the wear comb or ring should be such that the angle O between these elements can be adjusted. This can also be achieved by bending the spacer. This multiple variability enables the wear inserts to be assembled as a modular system from prefabricated sub-elements as required.

The wear comb 14 (FIG. 7) consists of wear bars (see FIGS. 6C, D, G) which are connected by a spacer to a common support. However, the wear comb or wear protection, as a shell or a circular segment (FIG. 6E) can also be connected directly to the elbow, ie without a spacer. Depending on the expected wear rate, a cast segment elbow with a reinforced outer elbow wall may be sufficient (Fig. 9).

The wear inserts described above, in particular with a wear comb composed of rods or as a single rod with a circular segment cross section (cf. FIG. 6E) can also be used in conjunction with conventional elbow segments (FIG. 10). In this respect, the rods serving to protect against wear need only be bent according to the radius of curvature.

BIBLIOGRAPHY:

Wypych, P.W .; Arnold, P.C .: Minimizing wear and particle demage in pneumatic conweying. Powder handling an processing, Vol. 5 (1993) 2, p .: 129-134

King, H.G .: A new, low-wear elbow for pipeline transport systems. Mineral Processing, (1989) No. 9, S.: 545 - 548

Claims

PATENT CLAIM

1. From an inlet elbow segment, a middle elbow segment and an outlet elbow segment, existing pipe elbows for conveying pipes of liquids or gases which may be contaminated with solids, characterized in that the middle elbow segment (2) is essentially straight _{and un} ςj _a ß whose axis (a) with the axis (b) of the inlet segment (1) forms a smaller angle (f) than it corresponds to half the total deflection angle (o) of the pipe bend, the outer inner wall surface line (21) of the middle elbow segment (2) meets the outer inner wall surface line (31) of the outlet elbow segment (3) at a point (S) which at the intersection of the imaginary extension (V) of the inner inner wall surface line (12) of the Inlet elbow segment (1) with the outer inner wall jacket line (31) of the outlet elbow segment (3) or by extending the middle elbow segment (2) relative to it in flow direction direction (4) is shifted (dimension t).

2. Pipe elbow according to claim 1, characterized in that the individual elbow segments are produced by separating them from a pipe and are assembled by welding, gluing or soldering or in another suitable manner.

3. Pipe elbow according to claim 1 or 2, characterized in that the individual elbow segments from a piece of pipe by Her¬ manufactured by separating at such an angle (Fig. 3A and 3D) and the two cut surfaces (Fig. 3C) according to one coaxial relative rotation by 180 ° (FIG. 3E) are joined (FIG. 3F), the different thicknesses of the cutting surfaces (FIG. 3C) resulting from the oblique cut matching each other exactly and the respectively desired angle of curvature being created between two segments (Fig. 3F).

4. Pipe elbow according to claim 1, characterized in that it is made in one piece by bending, casting, pressing, spraying, drawing or the like, with instead of the cut lines between the elbow segments the manufacturing process correspondingly rounded transitions arise (Fig. 4A, B) .

5. Pipe elbow according to one of claims 1 to 4, characterized in that on at least one end face connecting means such as flanges (4) (Fig. 5A), screw connections (5) (Fig. 5B), sleeves or the like are provided.

6. Pipe elbow according to one of claims 1 to 5, characterized in that the inner wall surface line of the elbow outside at least in the central region a rod (6) (Fig. 6C) with broken (Fig. 6A) or unbroken (Fig. 6B ) Wearing leading edge as wear protection. 97/19286 "-, _-,

PCT / DE96 / 02166

1 4

7. Pipe bend according to one of claims 1 to 5, characterized in that the inner wall surface line of the manifold outside at least in the central region a plurality of side by side arranged rods (6) with broken or unbroken edge (Fig. 6A and Fig. 6B) as Ver ¬ wear protection.

8. Pipe elbow according to claim 6 or 7, characterized in that the / the anti-wear rod / rods each have a circular, elliptical, rectangular or flat cross section / s (Fig. 6C and Fig. 6D).

9. Pipe elbow according to claim 6 or 7, characterized in that the / the wear protection rod / rods is / are made by flat rolling or flat grinding of a round rod (Fig. 6C and Fig. 6D).

10. Pipe bend according to one of claims 7 to 9, characterized in that the rods are fixed so spaced that solid particles are deposited and can protect the pipe wall against wear (Fig. 6D above and middle).

11. Pipe elbow according to claim 1, characterized in that the inner wall surface line of the elbow outside carries at least in the central region a shell-shaped wear protection body which extends circumferentially only to the area at risk of wear (Fig. 6F).

12. Pipe bend according to claim 11, characterized in that the shell-shaped wear protection is made by Tei¬ len a suitable pipe.

13. Pipe bend according to one of claims 6 to 11, characterized in that the wear protection elements are made of metal, ceramic, plastic, rubber or a combination of these substances.

14. Pipe bend according to one of claims 7 to 10, characterized in that selected rods (7) (Fig. 6G) are firmly connected to the tube wall and serve as a holder for interchangeable wear elements (8) inserted between these rods (7) .

15. Pipe bend according to claim 14, characterized in that the replaceable wear elements (8) protrude above the selected rods (7) in height (Fig. 6G).

16. Pipe elbow according to claim 15, characterized in that the replaceable wear elements (8) are made of a particularly wear-resistant material.

17. Pipe bend according to claim 16, characterized in that the selected rods (7) and the interchangeable wear elements (8) have mutually complementary profiles in order to ensure the function of the fixing regardless of the position. 1 6

18. Pipe bend according to one of claims 6 to 17, characterized in that the inserts serving to protect against wear are fastened by a detachable connection and can be exchanged after reaching a certain material removal (Fig. 7).

19. Pipe bend according to one of claims 6 to 18, characterized in that the inserts used for wear protection from three main parts, namely a holder on the pipe by means of a retaining disc (11) (Fig. 7) or a retaining ring (12) (Fig. 8 ), a spacer (13) (Fig. 7 / Fig. 8) and a wear comb (14) (Fig. 7) or a wear shell (15) (Fig. 8).

20. Pipe bend according to one of claims 6 to 19, characterized in that the angle between the spacer (13) and the wear comb (14) or the wear shell (15) by an articulated connection (16) or by bending the spacer ver ¬ is changeable or adjustable.

21. Pipe elbow according to claim 19 or 20, characterized in that the spacer (13) (Fig. 7) on the inlet side against the flow direction protrudes so far into a front delivery pipe that this elevation the connection point between the bracket on the pipe and protects the spacer against wear of the solids.

22. Pipe bend according to one of claims 19 to 21, characterized in that the length of the part of the spacer (13) (FIG. 7) protruding into the elbow can be changed by sliding the spacer against the holder on the tube (11, 12).

23. Pipe elbow according to one of claims 19 to 22, characterized in that the wear comb (14) or the wear shell (15) on the circumference of the Krümmersegmentε by rotating or moving relative to the spacer (13) or by turning or Tor¬ dieren the spacer ( 13) is relocatable.

24. Pipe bend according to one of claims 19 to 23, characterized in that the holder on the tube (11, 12) either by the flange screws and / or by one or more tongues (18) on the circumference or, in particular with screw connections and Sleeves, is centered on the end face of the elbow by a fully or partially formed circular collar (12) which bears against the inner wall.

25. Pipe bend according to one of claims 1 to 24, characterized in that the inner wall surface line of the bend outside is formed at least in the central region with a thicker wall thickness (Fig. 9).

26. Bent pipe elbow for pipelines for conveying liquids or gases which may be contaminated with solids, characterized in that the inner wall surface line of the outside of the elbow, at least in the central region, has at least one Rod with broken or unbroken leading edge as wear protection, this / these rod / rods are bent according to the radius of curvature (Fig. 10).