EP1261476B1 - Extruder for vegetable small parts, which are mixed with a binding agent, for producing compact strands - Google Patents

Abstract

The invention relates to an extruder (1) for producing compact strands (2) from vegetable small parts, which are mixed with a binding agent, for producing pallet bearers, profiles or the like. In order to reduce the structural complexity and the space requirements of the extruder, the invention provides that, while avoiding the provision of a piston-type extruder, the system for shaping and conveying the strand is composed of conveyors (12, 13, 14) which continuously revolve like a chain and in whose feed gap thermal energy, especially saturated steam, is introduced into the small part mixture (7) that has not yet been compacted. The condensation of the steam initiates the hardening of the strand during the shaping thereof and during its advance in the passages.

Description

The invention relates to an extrusion press for with Binding agents mixed vegetable small parts for education compact strands for the production of pallet blocks, Moldings, profiles or the like with an arrangement for Forming, compacting and conveying the strand as well with an arrangement for the purpose of introducing thermal energy Setting of the binder.

With the designation "compact strands" the 'Invention of the prior art for the production of Differentiate chipboard. According to DE-44 23 632 A1 grit mats made of glued or unglued grit formed, first preheating with a Air-conditioned fluid carried out from air and water vapor which flows through the spreading material. Doing so Condensation of the water vapor in the grit to be bought taken. Then the pre-treated in this way Spreading mat in a continuous press or in a cycle press by hot pressing to the final one Particle board deformed.

Such technology is used to form compact strands unsuitable, especially when it comes to the Form strands using an extruder and end the curing of the individual benefits, e.g. B. by sawing, separate.

In the known extrusion press according to DE-29 32 406 the strand first in a piston cold extrusion press formed, calibrated and heated by a Hardening channel pressed. The length of this extrusion press is depends on the cross section of the strand and requires one extraordinary space requirements. Besides, the performance such an extrusion press because of the small Limited thermal conductivity of the material.

Such extrusion presses have also been tried to work with steam. With EP 0 376 175 B1 proposed that compacted in an extruder Batch by one at the extrusion press subsequent reactor to be transported by the Edge zone of the strand by water, water vapor or additional liquid or vaporous binder higher humidity is brought. With these The process is all about the surface structure to change the strand. A shortening or This does not improve the setting time.

Finally, it is known from DE-A-24 54 280, the extruded from intermittent extrusion Waste products from vegetable fibers with the help of to encircle the shaped jaw conveyors and advance to move. In this case, however, the mold jaw conveyors have only the task of closing the previously rigid curing channel replace. In addition, the state of the art requires that the strand is formed in a piston extrusion press before it can run into the mold jaw conveyor. The The strand is bound by the penetration of heat what in the area of the curing zone from the outside Brings difficulties to the core of the strand cure.

Another press is from EP 0 383 572 A. previously known.

The invention is based on the object continuous extrusion press for manufacturing to develop more compact strands, both from constructive effort and space requirements much easier than the previous ones Piston extrusion works.

This task becomes the characteristics of the unit Claim 1 solved.

As Shaped jaw conveyors trained conveyors include the Strand across its entire circumference from all sides. They serve to educate and maintain the Strand form, as well as for applying the press energy.

The areas of the conveyor facing the line, especially the pairs of shaped jaws should preferably be used at least in the funding area a smooth as well form continuous shape retention area for the The outer contour of the strand being formed is flat and is generated smoothly.

a) die Zufuhr der Wärmeenergie erfolgt im Wesentlichen vornehmlich durch Einbringen von Dampf in das lose Kleinteilgemenge in einem Förderbereich vor oder während der Formgebung;

b) der Wärmeenergiestrom ist in den Innenbereich des Kleinteilgemenges derart gerichtet, dass eine Durchströmung vorwiegend von innen nach außen erfolgt;

c) die Abbindung des Stranges erfolgt bei Anwendung von Sattdampf durch dessen Kondensation;

d) der geformte Strang durchläuft eine erwärmte formerhaltende Führung unter Meidung zusätzlicher Press- oder Wärmeenergie.

Another embodiment advantageously describes the following features:

a) the supply of thermal energy takes place primarily by introducing steam into the loose batch of small parts in a conveying area before or during shaping;

b) the heat energy flow is directed into the inner region of the mixture of small parts in such a way that a flow mainly takes place from the inside to the outside;

c) the binding of the strand takes place when saturated steam is used by its condensation;

d) the shaped strand passes through a heated shape-maintaining guide while avoiding additional pressing or thermal energy.

The subject of the invention is thus a new one Process feasible, according to which as a heat energy source mainly steam into the small parts batch is introduced before this is formed into a strand. The thermal energy introduced must be so large that binding only through the condensation of the steam of the binder and thus a hardening of the strand in the paths are led. To the efficiency of To increase steam delivery, the invention teaches steam in To direct the interior of the small parts batch in such a way that a flow through the small parts mixture predominantly done from the inside out.

If one starts from this teaching, then the educated needs and only strand that is already curing to be guided with little friction until the shape is maintained the setting is complete. The necessary ones Guide means should be warmed to none To let heat losses occur. But it is not intends to additional in the areas of this tour Introduce curing energy into the strand.

The principle of operation of the invention thus consists in the reaction of the Binder in motion so that a a relatively short span of the strand is sufficient, to bring about the binding.

The one introduced into the loosely poured mixture of small parts Vapor is said to largely condense there Pressure build-up in the compression afterwards, but not yet completely cured product strand is avoided.

Suitable as conveyors are particularly by chain type rotating mold jaw conveyors. In their place, however also encircling steel belts or other equivalent effects Conveyor with appropriate stability and tear resistance be used.

The conveyor entry area is through wedges gently approaching each other, whose wedge angle is a measure of the compression of the Small parts mixture is. In practice there has been one Compression of 3: 1 proved to be useful, but expediently this wedge angle can be adjustable should according to the compaction of the small batch Desire to change.

Only those conveyors in the inlet area are preferred wedge-shaped, the upper and Form bottom. The others, on the sides of the Strands acting on the conveyor form according to one Embodiment of the invention in the inlet area Shaft, the height of which is adapted to the wedge angle. Several Shaft-forming conveyors are on the same level arranged one above the other. A middle sponsor owns the width corresponding to the height of the to be formed Side surface of the strand and runs over the entire Conveyor line with. The up or down on it adjacent conveyors only cover the gusset from the side and have only one length until the strand is completely enclosed by the sponsors.

An embodiment of the invention is also an arrangement with the controlled feeding of the small batch in the infeed area of the conveyor must be ensured can. In the exemplary embodiment, it is provided that in the inlet area of the arrangement for shaping and Promote the strand at least one parallel or Conveyor aid extending slightly at an angle to the strand axis the small parts batch is arranged. This grant can, for example, be driven by rotating Screw conveyors exist.

If the conveying aids are hollow, can by these supplied the thermal energy, especially the steam and be directed into the interior of the small parts batch. Because of the tapered shape of the Infeed area, the conveyor aids can be recommended tapered in the direction of conveyance.

With the help of such an arrangement it is also possible to run a longitudinal one in the strand to be formed Channel. For this purpose, the Strand axis a conveyor aid as a rotating conveyor mandrel trained, but which must not be open on the front, because otherwise the one brought into the mandrel Thermal energy, mainly steam, through the formed Strand channel could escape.

In another embodiment of the invention the conveyor in the infeed area and along the Conveyor line supported by heated pressure rollers, the are stored in heated pressure holder rails. Thereby the result is that there are none along the conveyor line Cooling of the strand can take place and that accordingly Condensation of the steam in the line takes place unhindered can.

At the end of the infeed area and at the beginning of the The conveyor section of the conveyor is according to the invention Pressure roller pair arranged, the distance for the maximum height of the strand is decisive. If you can You measure the contact pressure of this pair of pressure rollers control over the density of what is being formed Strand. You can use this contact pressure, for example can be determined by a load cell as Use control means to control the speed of the conveyor aids, located in the inlet area of the arrangement change. In this way the constancy of density of the strand generated.

Another embodiment of the invention relates to Spatial shape of the mold jaws or the mold jaw conveyor.

After that are the facing edges the pairs of shaped jaws interlocking in a cylindrical shape convex and concave and centric to the Curvatures mounted on each other in such a way that even at slightly angled mold jaws one maintain uninterrupted shape maintenance area remains.

In this way it is achieved that the Mold jaw conveyor no gaps between the mold jaws arise, the evasion of small plant parts would enable. On the other hand, they face each other Edge with a certain play between them distanced so that one in the strand might forming overpressure of the steam by escape of the Steam can be broken down.

In order to facilitate the production of such shaped jaws, The invention provides that the single mold jaw is composed of several parts, after which a middle part its frontal edges are convex and concave Has shape, the middle part along its length lateral edges is connected with webs, which at one The front edge of the neighboring one Grasp the middle part in a fork shape and the limb joint form.

Such webs are also preferably used for the Strand to produce beveled edges, as with Pallet blocks are required. Grasp the webs hence the shape-forming surface of the middle section and point the required bevels in the overlapping part.

Of course, the webs are also on the front concave or convex to avoid any at these points Changes in shape of the bevelled edge surfaces of the To create strands.

Figur 1:

eine schematische Teil-Seitenansicht einer kontinuierlichen Strangpresse,

Figuren 2 und 3:

Teil-Seitenansichten des Einlaufbereiches der Strangpresse gemäß Figur 1 in verschiedenen Ausführungsarten,

Figur 4:

einen Querschnitt durch die Förderstrecke der Strangpresse entlang der Linie IV-IV mit einem von Formbackenpaaren umgriffenen Strang,

Figur 5:

einen Vertikalschnitt durch den Einlaufbereich der Strangpresse längs der Linie V-V in Figur 1 und

Figuren 6 bis 8:

Seitenansicht, Draufsicht und Querschnitt (teilweise im Schnitt) durch aneinander gelenkte Formbacken.

Exemplary embodiments of the invention are shown schematically and for example in the drawing. Show it:

Figure 1:

2 shows a schematic partial side view of a continuous extrusion press,

Figures 2 and 3:

Partial side views of the inlet area of the extrusion press according to FIG. 1 in different types,

Figure 4:

3 shows a cross section through the conveyor line of the extrusion press along the line IV-IV with a strand encompassed by pairs of shaped jaws,

Figure 5:

a vertical section through the inlet area of the extrusion press along the line VV in Figure 1 and

Figures 6 to 8:

Side view, top view and cross-section (partly in section) through articulated jaws.

In the embodiment of Figure 1 is a side view the front part of an extrusion press (1) to form a compact strand (2) shown, which an arrangement (3) for Shape and compression of the strand (2), one Arrangement (4) to promote the strand (2) and one Arrangement (5) for introducing thermal energy primarily in the form of steam in a loose batch of small parts (7) contains.

It is assumed that the small parts batch (7), which is mixed with binders and from vegetable Small parts exist through a feed channel (6) any shape in the inlet gusset (8) of the arrangement (3) the shape.

The arrangement for shaping, compacting and conveying the strand (2) consists of the embodiment rotating mold jaw conveyors (12,13,14). The strand upper and lower bounding jaw conveyors (12,13) are circumferentially guided and form over deflecting rollers (16) in the inlet gusset (8) a wedge, the wedge angle decisive for the size of the compression of the introduced loose batch of small parts (7). In the embodiment is considered appropriate, a compression of about 3: 1 to choose, but largely as required can be changed. It is conceivable to close the wedge angle change, for example by changing the distance between the Deflection rollers (16) changed from each other.

Arrive at the inlet end of the inlet gusset (8) the runs (23, 24) of the upper and lower Mold jaw conveyor (12,13) in the effective range of a Pressure roller pair (17), the distance of which is the cause is how thick or high the strand (2) in its final form is.

In the further course of the direction of funding Mold jaw conveyors (12, 13) are made of pressure rollers (18) in their determined by the pair of pressure rollers (17) Location held. The pressure rollers (18) are supported Pressure holding rails (19). Both the pinch rollers (18) as well as the pressure holding rail (19) are heated to a Cooling of the strand (2) during the passage of the Avoid conveyor section (4).

For binding the one in the small parts batch Binder is in the embodiment of the invention Steam used, mainly along the arrows 5 from inside into the still loose batch of small parts (7) is introduced in such a way that the steam inside out can flow outside. This ensures a uniform Moisturize the loose small batch with steam the aim is to bind the binder exclusively by condensing the steam.

The embodiment of the invention therefore differs from the prior art Technique in that to bind the binder required heat energy in the loose small batch (7) is introduced before it is shaped and compressed becomes.

In the loose batch of small parts to be pressed from small plant parts it is a so-called non-climbable mixture. Accordingly expected in the inlet gusset (8) batch of small parts located at an angle to each other running run (23,24) of the mold jaw conveyor (12,13) taken along and compressed accordingly.

Nevertheless, it is suggested additional subsidies in the infeed area of the Extrusion press (1), for example in the form of one or to provide several screw conveyors (9) which the Have task, that in the feed channel (6) Small batch (7) targeted in the inlet gusset (8) To promote trums (23,24). It lends itself to this Conveying aids (9) hollow, with holes in the To provide wall and thereby the thermal energy or Steam inside the loose batch of small parts (7) initiate. Of course, the tie closes not out the steam through other centric Introduce cables into the small parts batch (7). With (11) are the steam outlet holes in the conveyor aids (9).

Because of the inlet gusset (8) it is recommended that Conveying aids taper conically in the conveying direction train to ensure an even supply of Bring small parts (7).

In the embodiment of Figure 2 is a variant represented such that several in the inlet gusset (8) Subsidies (9), for example in the form of Screw conveyors, sometimes arranged at an angle, whose direction of conveyance is targeted to the point between the Pressure roller pair (17) are directed.

It is also shown that one of the pressure rollers (17) is equipped with a load cell (20), which the Spreading pressure that the small parts mixture (7) measures Passing the pair of pressure rollers (17) exercises. This Pressure measuring device (20) can do this for control purposes exploited, the flow rate of the small parts batch (7) change, for example by changing the Speed of the conveyor aids (9) can happen. To this Way becomes a dependent function between the pressing pressure of the pair of pressure rollers (17) and the delivery rate of Small parts batch (7) achieved to stabilize the To bring the density of the strand (2).

In the exemplary embodiment in FIG. 3 it is shown that a middle rotating conveyor mandrel (22), whose axis of rotation in the strand axis lies in those in formation Strand (2) up to a point behind the pair of pressure rollers (17) protrudes. This rotating mandrel turns a Strand channel (21) formed in the strand (2) as he for example for the production of pallet blocks is appropriate. This rotating conveyor mandrel (22) can be hollow and loaded with steam.

However, the conveyor mandrel (22) must be on the front be completed to prevent the steam can escape through the strand channel (21).

In the embodiment of Figure 4 is a cross section along the line IV-IV in Figure 1 through the strand (2) shown over its entire scope of Mold jaw pairs (25,26) is encompassed. With this strand (2) it is a compact strand that especially for the production of pallet blocks is used. Accordingly, the longitudinal edges are of the strand (2) with bevels (39).

The upper and lower pair of mold jaws (25) is thus like this trained to produce this bevel (39). The lateral mold jaw pairs (26) are in cross section however, simply prismatic and determine the Side faces of the strand (2). The inside Areas of the mold jaw pairs (25, 26) are as Shape maintenance areas (27) are formed and procured in such a way that during the passage of the strand through the Conveyor line (4) a flat and uninterrupted surface form to irregularities on the mantle of the strand (2) to avoid.

Grip the outer surfaces of the pairs of mold jaws (25, 26) Pressure rollers (18) in the pressure holding rails (19) are stored. Both the pressure rollers (18) and the Pressure holding rails (19) are heated and prevent that Drain the heat of the strand (2).

In comparison of Figure 4 to Figure 1 one should assume that only the top and bottom Mold jaw pair (25) in the inlet gusset (8) each other approach in a wedge shape, whereas the side ones Mold jaw pairs (26) from the very beginning in FIG. 4 take the position shown. The spatial assignment is shown in Figure 5, which is a cross section along the Line V-V in Figure 1 shows. The cross section of the strand (2) is shown here in symbolic dash-dotted lines. The upper and lower mold jaws (25) are still in Distance to this.

Of the side mold jaw pairs (26) and the attached additional lateral sides adjoining on both sides Guide conveyors (30) becomes a shaft (28) in the area of the inlet gusset (8), which prevents the Small parts batch located between the runs (23, 24) can dodge sideways. This side Leaders (26.30) are common across verticals Deflection rollers (29) performed. Like the figure 1 symbolically shows is the length of the side mold jaw conveyor (14, 26) over the entire length of the extrusion press (1) led, whereas the adjacent side Guide conveyor (30) only a length to the end of the gusset (8). The dimensions are in figure 1 shown in dash-dot lines.

The spatial shape shown in Figures 6 to 8 chain-like interlocking mold jaws (25,26) disclose an independent subject of the invention Registration.

After that are the facing edges (32,33) of the mold jaw pairs (25,26) interlocking cylindrical convex and concave and centric to the curvatures, so that also with slightly angled mold jaws (25) one uninterrupted shape maintenance area (27) upright preserved. If the mold jaws (25, 26) give shape like this are trained that they also the bevels (39) of the Can produce strands (2), then the Crosspieces (37) spanning mold jaw pairs (25, 26) exhibit. With such a constellation, it is natural difficult to create the individual concave edges (33).

For this reason, FIGS. 6 to 8 disclose to form the individual mold jaw (25, 26) in several parts. On Middle part (31) is on its side edges (36) Bridges (37) connected to the shape preservation area (27) tower. In this way it is possible for the Middle part (31) the concave or convex face Edge formation (32.33) to convey.

On the other hand, the side webs (37) are on one End face fork-forming (38) arranged. This fork (38) dominates the concave front edge (33) of the Middle part (31) and encompasses the convex edge (32) of the adjacent central part (31). In the area of this The fork is the swivel joint (34), which in the Embodiment consists of an articulated bushing (35). The edges of the webs (37) also fit into one another convex and concave, because that's what it takes care of must be that the bevels (39) (see Figure 4) of the strand (2) must be continuously mapped.

The webs (37) and the middle part (31) are in conventionally connected together, for example pinned or screwed.

The drive of the shaped jaw conveyors (12, 13, 14, 15) can be in be designed in the usual way, for example by that the individual mold jaws (25, 26) are rack-like Have profiles that match Intervene the profiles of the deflection rollers (16). It is also conceivable, the deflecting rollers (16) in cross section to be prismatic in order to create a Form fit with the form jaw conveyors (12,13,14,15) to bring about. Finally, it is also conceivable driver elements between the individual mold jaws to arrange the tensile load from the swivel joints (34) to reduce.

PARTS LIST

1

extruder

2

strand

3

Arrangement for shaping

4

Order for funding

5

Arrangement for introducing thermal energy

6

feed

7

loose batch of small parts

8th

inlet pocket

9

Conveying aid (screw conveyor)

10

conical taper

11

Steam outlet hole

12

upper mold jaw conveyor

13

lower mold jaw conveyor

14

lateral mold jaw conveyor

15

Shaft-forming shaped jaw conveyor

16

deflecting

17

Pair of pressure rollers

18

pinch

19

Pressure retaining rail

20

Load cell

21

strand channel

22

rotating mandrel

23

Trum

24

Trum

25

upper / lower pair of molded jaws

26

pair of side mold jaws

27

Shape retention area

28

shaft

29

vertical deflection roller

30

lateral guide conveyor

31

midsection

32

convex front edge

33

concave front edge

34

swivel

35

joint bush

36

side edge

37

web

38

fork

39

Bevel of the strand

Claims (16)

1. Extruder for small pieces of vegetable matter mixed with binding agent for forming compact extrudates (2) for the production of pallet bearers, battens, profile sections or the like, wherein the extruder is provided with an arrangement for shaping (3), compressing and conveying (4) the extrudate (2) and with an arrangement for introducing thermal energy (5) for the purpose of curing the binding agent, characterised in that the arrangement for shaping (3), compressing and conveying (4) the extrudate (2) consists of die conveyors (12, 13, 14) circulating continuously in the manner of a chain engaging round the extrudate (2) over its entire perimeter from all sides in whose entry nip (8) the arrangement (5) for introducing the thermal energy is provided.
2. Extruder according to Claim 1, characterised in that the surfaces of the conveyor or the pair of dies (25, 26) form at least in the transport region a smooth and uninterrupted shape-maintenance surface (27).
3. Extruder according to Claim 1, characterised by the following characteristics:

   a) the thermal energy is substantially supplied primarily by introducing steam into the loose mixture of small pieces (7) in a transport region (5) ahead of or during shaping (3);

   b) the stream of thermal energy into the interior of the mixture of small pieces (7) is directed in such a way that flow through it ensues predominantly from the inside to the outside;

   c) the extrudate (2) is cured by using saturated steam through whose condensation;

   d) the moulded and compressed extrudate (2) passes through a heated shape-maintaining guidance system (12, 13, 14).
4. Extruder according to any of Claims 1 to 3, characterised in that the inlet region (8) of the conveyors (12, 13) is formed by wedge-shaped strands (23, 24) gradually approaching one another whose wedge angle is a measure of the compression of the mixture of small pieces.
5. Extruder according to Claim 4, characterised in that the conveyors (15) circulating in different planes form a shaft (28) in the inlet region whose height is adapted to the wedge angle.
6. Extruder according to Claim 5, characterised in that a plurality of shaft-forming conveyors (30) are arranged above one another or beside one another in the same plane.
7. Extruder according to any of Claims 1 to 4, characterised in that in the inlet region (8) of the arrangement for shaping (3) and transporting (4) the extrudate (2) at least one transport aid (9) for the mixture of small pieces (7) is arranged to extend parallel or at a slight slant to the axis of the extrudate.
8. Extruder according to Claim 7, characterised in that the single transport aid (9) consists of screw conveyors driven in circulating manner.
9. Extruder according to Claim 7 or 8, characterised in that the transport aids (9) are of hollow construction and serve to supply thermal energy.
10. Extruder according to Claim 8 or 9, characterised in that the transport aids (9) taper conically in the transport direction.
11. Extruder according to any of Claims 7 to 10, characterised in that the transport aid extending in the axis of the extrudate is constructed as a rotating transport mandrel (22) for forming a central channel (21) in the extrudate (2).
12. Extruder according to Claim 1, characterised in that the conveyors (12, 13, 14) are supported in the inlet region (8) and along the transport segment (4) by heated pressure rollers (18) which are mounted in heated pressure-keeping rails (19).
13. Extruder according to Claim 1, characterised in that at the end of the inlet region (8) and at the start of the transport segment (4) of the conveyors (12, 13, 14) a pair of pressure rollers (17) is arranged whose spacing determines the maximum height of the extrudate (2).
14. Extruder according to any of Claims 7 to 11, characterised in that the transport speed of the transport aids (9) is controllable as a function of the contact pressure of the pair of pressure rollers (17).
15. Extruder according to Claims 1 to 3 of the following, characterised in that the front end edges (32, 33) facing towards one another in pairs of dies (25) in the conveyors (12, 13, 14) meshing in one another are of cylindrical convex and concave construction and mounted (34) centrally on one another relative to the curvatures in such a way that even when the dies (25) are slightly offset relative to one another an uninterrupted shape-maintaining surface (27) is maintained.
16. Extruder according to Claim 15, characterised in that the single die (25) is assembled from a plurality of parts whereby a central section exhibits convex and concave shaping at its front end edges (32, 33) and the central section (31) is connected along its lateral edges (36) to webs (37) which engage in the shape of a fork (38) on a front end of the front end edge of the neighbouring central section and form the link joint (34).

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