DE1529828A1 - Extrusion press or extruder with press screws for pressing out thermoplastic materials - Google Patents

Description

Compagnie des Ateliers et iorges de la Loire, (St Chamond J? Irininy - St Etierme - Jaoob-Holtzer), 12, rue de la Ro & hefoucauld, Paris, France

"Extruder or extruder with press tendon cite n for extrusion of thermoplastic materials "

The invention relates to extrusions or extruders with compression chords for extruding thermoplastic or other behave like such behaving substances.

In the context of the increasing application of such devices it has proven necessary to increase their natural degassing effect by providing systematic degassing zones.

However, it is often found that the sealing of the press " . materials between the sesohiokungsstelle of the screws and the or dgn degassing zone for limited feed quantities

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Bank account: Dresdner Bank AG Herne - Pottscheckfconto: Dortmund 55868 - Telegrem address: Behrpateni · Hermwesttaten

is imperfect. 3s this results in an oxidation of the priced Material, - 'v / eil this at the time in which because of its thermal instability compared to the working temperature, it has the greatest tendency to disintegrate, in fact exactly the air is located. The degree of this oxidation is still increased, if the one or more degassing openings are connected to a vacuum source. The one in the degassing zone The overpressure generated facilitates the passage of the from the loading zone coming air that can move through the interruptions in the continuity of the Y / erstoffes.

Another disadvantage of the known methods and presses is that they do not have a sufficiently large cross-section for the passage of the material into the degassing zone. ■ ^; . . ".";".

On the one hand, the material is not always sufficiently relaxed, to enable the fee contained in the solution to be released and the degassing is imperfect »On the other hand exists when the task of the extrusion press with a Material is charged, which can compress less than that of the cross-son lacing through which it can pass must, corresponds to the risk that the material, in that it relaxes elastically in the degassing zone, by the one or more outlet openings for the gases exits.

Ultimately, this means _{that r is} only a comparatively small one

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Surface in the passage profile is available that Formation- "the thin layer, endangered, which for. The induction the effect of rapid evaporation and distillation .in exchanges -.;, ', velohe with such thin layers work; 'is required'. The general EiitgasuL ^ svorrar-g, V / -SIcher both the distance between the lattrial parts trapped air, such as the evaporation of surface moisture the Js-ilcteti and -absorption, like the discharge; the volatilized elements- which at working temperatures be formed, encompassed, runs imperfectly from this G-round. . ..- .. "-_" .-.,.

Subject matter of the invention are improvements to devices " of the type described, which in particular is an effective ^ asung while at the same time facilitating the operation of the Enable extruders «-. . .

- According to a harvest, i'ferkmal the invention is between a work stage and the subsequent relaxation stage, in which ... the "material is degassed", a stage switched on, through which the regular: material supply the relaxation level is secured .. .-. -. ■ -..- '. ^:

According to a further feature of the invention, between these Work stage and the regular supply of material to the relaxation stage effecting stage switched on a further stage, in which the presoftub speed of the here

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material under free pressure is slowed down and this is homogenized.

A corresponding stage in which the material is degassed is provided on the outlet side of the decompression stage.

The following is merely an example to which the er- ■ but is by no means restricted to an embodiment an extruder with two in the same direction at the same speed rotating screws that run parallel to each other " and their threads intermesh, with the features of the invention using the illustrations, described " Of these is

Pig. 1 an axial longitudinal section through part of the extruder,

and ■ - '-._.-. : ■ '■ ",: .- ■■■■■

.Fig. 2, section along line II-II of Pig. 1. .

1 in the figures denotes the pair of screws which form a working stage through which the material is moved forward and the one or more, downstream other work stages ahead of her can be. On the downstream side of this stage, the material fills the area 2 between the bore of the putter 3 and the pair of screws 4. The snails of this pair of snails know less deeply engaging .Sefe »threads on, ·

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whose bottom diameter is larger 3I3 the bottom diameter Threads of the worms 1, By appropriate dimensioning of the outer diameter of the threads of the worms 4 "remains up to the walls of the holes in the chuck 3 relatively large room 2.

In this space steht'das material under a clear Dructo The purpose of the circulating in it threads 4 substantially, a gegenaeitige cleaning the surface is to prevent the uewindegänge and the formation of ledges on its bulbous shaped spindle ^7.

The material that accumulates in the room 2 then becomes sucked into the feed zone te4Hfte formed by the screw pair 5. These snails have only a small number of Threads, whereby considerable mechanical friction is prevented, leading to the formation of overheating zones in the material would lead. The outer diameter of the threads of these screws is equal to the diameter of the bore the fodder 3 »reduces what is unhindered for you i; en required ^ if game.

, Quörseianitt, b the threads of the worms 5 is smaller

• as the cross section of the; G-turns of the screws 1.

The decompression and degassing stage created by the screws 5 is regularly supplied with the material

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from worms 6, their cross-section c between the threads largeiMind is at least equal to the cross section a is »I) ie! form of the G-thread turns is chosen so that a large ', / heat exchange area and results in a layer of the material that is as thin as possible in order to avoid the "usual" η, / poor of exchange for thinner Bring about shift.

The one or more openings 7 provided in the i'utter 3 are connected to a UhterdBuekquelle, through which all gaseous elements are sucked out to the outside of the housing of the putter. ., -. ' ■ -. .. .-.,; -

On the downstream side of this decompression and degassing stage there is a further stage in which the material is again subjected to free compression and homogenization takes place, which is designed similarly to the stage provided upstream. This stage is formed by worms 8, the threads of which are small and interlocking in their mutual cleaning "securing" manner. The free tree 9 forms a zone in which the feed rate of the material slows down, which here before its entry In a new work step 1Ö a free pressure action and homogenization will be subjected. Through work step 10 'the material is directed to the outlet opening of the press ^ You can peel one or more more painful further work steps afterwards the son corners, 10 is slightly smaller than the straight cross-section b

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between the threads _c lengths of the screws 5.

If substances to be processed, which are loaded in a particularly high -Kaße with gaseous to remove products, so the worm can also be arranged so that the stage which is formed by the screw 8 _t a further supply stage, as indicated at 5 , then a decompression stage like the one marked 6, with renewed withdrawal of the gaseous substances, then a stage of free pressure action, like the one marked 8 _; e work stage, like the one marked with 10 ', etc. υ a ch ge sch afc et v / erden.

It goes without saying that the invention is not limited to the embodiment described above and the embodiment shown in the figures limited, but numerous changes are possible. So the invention is also strengthened on " Extrusion or extruder, in the case of soft.-the screws run in opposite directions. In all cases, the number of each other cooperating snails auolx be coarser than two and this can be in one and the same level or in different Levels to be arranged.

Claims;

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Claims (5)

Patent claims: 1. Screw press (extruder) for the extrusion of thermoplastic resins or similarly behaving substances, characterized in that between a Arbeitsagbufe and the one following it Decompression and degassing stage of the compressed material a stage through which an even supply of the liekorapi-e ssi ons level is secured is switched on. 2 .. screw press according to claim 1, characterized in that the * intermediate stage consists of screws with a small number of SKkK threads ^ än ^ eη, the cross-section between the sewing turns than the cross-section between the threads, lengths of the screws of the preceding Feed or work stage and as the cross-section between the Szkxs threads of the following decompression stage. • * 3. Screw press according to claim 1 and 2, characterized in · that between the feed or working stage and the Be schickungsstufe for the following stage, a stage is turned on, in which the material is under a non-impact printing, its Fortbewegun ^ sgeschwindigkeit slows and is homogenized. 4. Screw press according to claim 5, characterized in that that between the feed or bed stage and the feed stage switched on stage off with each other in on » 909881/1177 BATH ORIGINAL handle standing snails, whose G-thread turns a • have a larger base diameter than the threads of the. The working stage and its outer diameter are dimensioned in such a way that "'up to the walls of the bore of the chuck a free space * space remains. 5. Screw press according to tinem of claims 1 to 4 »characterized in that on the downstream side of the decompression stage also a stage of free pressure _? in which the speed of movement of the material is slowed down and the material is homogenized. 909881/1177 Blank page