DK162148B

DK162148B - Apparatus for producing a chemically reactive blend of at least two components

Info

Publication number: DK162148B
Application number: DK176886A
Authority: DK
Inventors: Adolf Bauer
Original assignee: Krauss Maffei Ag
Priority date: 1985-07-12
Filing date: 1986-04-17
Publication date: 1991-09-23
Also published as: EP0218802B1; JPH0628853B2; JPS6216108A; EP0218802A2; CN1007137B; DK176886D0; CN86104568A; EP0218802A3; DK176886A; DE3525004C2; DK162148C; ATE62442T1; DE3525004A1

Abstract

The device comprises a mixing chamber, leading into which there are feed lines and from which there are return lines for the plastics components and which has an outlet opening for the mixture of the said components, as well as a control and displacement plunger, which can move back and forth within the mixing chamber, interconnects the feed and return lines of each component when in a recirculation position and releases the inlet into the mixing chamber when in a mixing position. In order to achieve a transfer from the feed line to the return line without any flow resistance for at least one plastics component when in the recirculation position, it is proposed that the feed line and the return line of at least one component are arranged in line with each other and the control plunger has at least one radial slit, via which the feed line and the return line can be connected in the recirculation position and that from the feed line there branches off a bypass line, which in a radial plane opens out into the mixing chamber in a discharge opening, which in the mixing position of the control plunger is opened simultaneously with the discharge openings for the remaining plastics components, the connection between feed line and return line being closed by the control plunger. <IMAGE>

Description

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Den foreliggende opfindelse angår et apparat af den i indledningen til krav 1 eller 7 angivne art.The present invention relates to an apparatus of the kind set forth in the preamble of claims 1 or 7.

Et apparat af denne type er kendt fra beskrivelsen til tysk patent nr. 12 82 522, ved hvilket der på omkredsen af 5 et styrestempel er aksialt forløbende omløbskanaler, gennem hvilke indløbsåbningerne fra tilførselsledningerne i recirkulationsstilling af styrestemplet bliver forbundet med de tilsvarende returledninger. På grund af fordringen om et lille blandekammer har styrestemplet en forholdsvis lille ID diameter, således at der ved arrangementet med to overfor hinanden beliggende omløbskanaler med så stort gennemstrømningstværsnit som muligt kan der kun blive en tynd skillevæg tilbage i styrestemplet mellem omløbskanalerne. Herved er der risiko for at denne mellemvæg eroderer og bliver gennembrudt 15 under virkningen af de med højt tryk i omløbskanalerne indsprøjtede formstofkomponenter, en risiko, som især er til stede ved formstofkomponenter, som indeholder fyldstoffer. Endvidere er de aksiale omløbsnoter strømningsteknisk ugunstige, da de under højt tryk transporterede komponenter to 20 gange må ombøjes 90°, hvorved der på grund af indre friktion sker en uønsket opvarmning af komponenterne og en beskadigelse af fyldstofbestanddelene, fx kan giasfiberstykker knække.An apparatus of this type is known from the specification of German Patent No. 12 82 522, in which, at the circumference of 5, a guide piston has axially extending bypass channels through which the inlet ports from the supply lines in recirculation position of the control piston are connected to the corresponding return lines. Due to the requirement for a small mixing chamber, the control piston has a relatively small ID diameter, so that at the arrangement of two opposite bypass channels with as large a flow cross section as possible, only a thin partition can be left in the control piston between the bypass channels. Thereby, there is a risk that this partition will erode and be pierced under the action of the high-pressure injection components injected into the orifices, a risk which is particularly present in plastic components containing fillers. Furthermore, the axial orbital notes are flow technically unfavorable, since the components transported under high pressure must be bent twice 90 °, thereby causing undesirable heating of the components and damage to the filler components, for example gias fiber pieces may break.

På grund af fordringen om så store tværsnitsarealer 25 som muligt i omløbskanalerne forbliver der mellem to overfor hinanden liggende omløbskanaler kun en forholdsvis ringe omkredsflade tilbage på styrestemplet, således at der i omkredsretningen kun findes en kort tætningsspalte ved cylindervæggen. Herved er der risiko for at de under højt tryk 30 stående formstofkomponenter strømmer forbi uden om omløbskanalerne og reagerer ukontrolleret med hinanden på uønskede steder.Due to the requirement for as large cross-sectional areas 25 as possible in the bypass ducts, only two relatively low circumferential surfaces remain on the guide piston between two opposite passageways, so that in the circumferential direction there is only a short sealing gap at the cylinder wall. Thereby, there is a risk that the high-pressure plastic components 30 flow past around the orbits and react uncontrollably with each other in undesirable places.

Fra tysk offentliggørelsesskrift nr. 30 19 548 er det allerede kendt at fremskaffe et så lille blandekammer som 35 muligt og om muligt store recirkulationsnoter ved at styrestemplet er aftrappet i diameter, idet recirkulationsnoterne er placeret i en del af styrestemplet med større diame-From German Publication No. 30 19 548, it is already known to provide as small a mixing chamber as possible and, if possible, large recirculation notes by steering the plunger in diameter, the recirculation notes being located in a portion of the plunger with larger diameters.

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2 meter og afgrener tilløbskanaler til indsprøjtningsåbningerne. Ved denne udførelsesform er der dog en risiko for at materiale, som afsætter sig ved aftrapningen påvirker styringsfunktionen af styrestemplet.2 meters and branch inlet ducts for the injection openings. In this embodiment, however, there is a risk that material depositing at the step-down affects the steering function of the guide piston.

5 Den opgave, som ligger til grund for opfindelsen, er at tilvejebringe en blandingsindretning af den indledningsvis nævnte type, i hvilken der i recirkulationsstillingen for mindst en formstofkomponent er en strømningsmodstandsfri overledning af formstofkomponenten fra tilførselsledningen til 10 returledningen.The object of the invention is to provide a mixing device of the type mentioned in the introduction, in which, in the recirculation position of at least one plastic component, there is a flow-resistant free transfer of the plastic component from the supply line to the return line.

Denne opgave løses som angivet i den kendetegnende del af krav 1 eller krav 7.This task is solved as set forth in the characterizing portion of claim 1 or claim 7.

I recirkulationsstillingen bliver komponenterne ledt over fra tilførselsledningen uden hindringer i den i flugt 15 med tilførselsledningen anbragte returledning, idet der opnås den fordel, at tilførsels- og returledningerne kan tætnes ved hjælp af i styrestemplet eller cylinderen anbragte ringtætninger. Dermed kan man med enkle midler sikre sig, at der fra tilførsels- og returledningen for den ene komponent 20 ikke kan nå nogen komponentbestanddele frem til området ved en anden, aksialt forskudt tilførsels- og returledning for en anden komponent.In the recirculation position, the components are passed over from the supply line without obstructions in the return line arranged in flight 15 with the supply line, obtaining the advantage that the supply and return lines can be sealed by means of ring seals located in the guide piston or cylinder. Thus, with simple means it can be ensured that from the supply and return line for one component 20 no component constituents can reach the area by another axially displaced supply and return line for another component.

Videre fordelagtige udformninger og videreudviklinger fremgår af underkravene.Further advantageous designs and further developments are stated in the subclaims.

25 Opfindelsen skal i det følgende beskrives nærmere un der henvisning til udførelseseksempler på tegningen. På tegningen viser:The invention will now be described in more detail with reference to exemplary embodiments of the drawings. In the drawing:

Fig. 1 et snit gennem et blandekammer med et i recirkulationsstilling placeret styrestempel med aftrappet ende-30 flade, fig. 2 et snit langs snitlinien II-II ifølge fig. 1, fig. 3 et snit igennem et blandekammer med et i blan-destillingen placeret styrestempel med aftrappet endeflade, fig. 4 et snit gennem et blandekammer med et i recir-35 kulationsstilling placeret styrestempel med en aksial recirkulationsnot, fig. 5 et snit langs snitlinien V-V ifølge fig. 4,FIG. 1 is a section through a mixing chamber with a recirculating guide piston with a stepped end surface; FIG. 2 is a sectional view along section line II-II of FIG. 1, FIG. 3 is a section through a mixing chamber with a control piston located in the blend distillation with a stepped end surface; FIG. 4 is a section through a mixing chamber with a control piston located in the recirculation position with an axial recirculation groove; FIG. 5 is a section along section line V-V of FIG. 4

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3 fig. 6 et snit gennem et blandekammer med et i recirkulationsstilling placeret styrestempel med en aksialt forskudt returledning for en af komponenterne, fig. 7 et snit langs snitlinien VII-VII ifølge fig.3 FIG. 6 is a section through a mixing chamber with a control piston placed in a recirculating position with an axially displaced return line for one of the components; FIG. 7 is a section along section line VII-VII of FIG.

5 6, fig. 8 et snit gennem et blandekammer med et styrestempel i blandestilling, hvor samtlige returledninger er placeret således, at de flugter med de tilsvarende tilførselsledninger, og 10 fig. 9 et snit langs snitlinien IX-IX ifølge fig. 8.6, FIG. 8 is a section through a mixing chamber with a control piston in the mixing position, where all return lines are arranged so that they align with the corresponding supply lines; and FIG. 9 is a section along section line IX-IX of FIG. 8th

Fig. 1-3 viser et blandekammerhus 1, i hvilket et styrestempel 2 med aftrappet endeflade 3 er bevægeligt frem og tilbage mellem en recirkulationsstilling (fig. 1 og 2) og en blandestilling (fig. 3), ved hjælp af et arbejdsstempel 15 4. Blandekammerhuset 1 indeholder endvidere to tilførsels ledninger 5 og 6, samt to til disse svarende returledninger 7 og 8. Styrestemplet 2 indeholder radiale slidser 9 og 10, gennem hvilke udmundingsåbningerne 11 og 12 for tilførselsledningerne 5 og 6 i recirkulationsstillingen ifølge fig.FIG. 1-3 show a mixing chamber housing 1 in which a steering piston 2 with stepped end surface 3 is movable back and forth between a recirculation position (Figures 1 and 2) and a mixing position (Figure 3), by means of a working piston 15 4. The mixing chamber housing 1 further contains two supply lines 5 and 6, and two corresponding to these return lines 7 and 8. The guide piston 2 contains radial slots 9 and 10, through which the outlet openings 11 and 12 for the supply lines 5 and 6 in the recirculation position according to FIG.

20 1 og 2 uden strømningshindringer ligger umiddelbart overfor og i flugtende arrangement i forhold til indmundingsåbningerne 13 og 14. Fra tilførselsledningen 5 er der afgrenet en sideledning 15, som indmunder i det radiale plan for tilførselsledningen 6 med en indløbsåbning 6 i blandekammeret 17 (fig.20 1 and 2 without flow obstructions lie immediately opposite and in flush arrangement with respect to the orifices 13 and 14. From the supply line 5, a lateral line 15 is branched, which opens into the radial plane of the supply line 6 with an inlet opening 6 in the mixing chamber 17 (fig.

25 3). Ved blandekammerets udgangsåbning 18 er der vinkelret til sluttet en kanalombøjning 19, i hvilken et stempel 20 er bevægeligt frem og tilbage. Endefladen 3 af styrestemplet 2 indeholder en aftrapning 21, ved hjælp af hvilken returledningen 8 holdes lukket i blandestillingen. Blandekammerudgangsåbnin- 30 gen 18 og et bestemt omkredsområde af tværsnitsfladen for kanalombøjningen 19 er tilpasset til den aftrappede endeflade 3 af styrestemplet 2. Ringtætninger 22 er placeret på begge sider af radialslidserne 9 og 10 i styrestemplet 2.25 3). At the outlet opening 18 of the mixing chamber, there is perpendicular to a duct bend 19 in which a piston 20 is movable back and forth. The end surface 3 of the guide piston 2 contains a step 21, by means of which the return line 8 is kept closed in the mixing position. The mixing chamber outlet opening 18 and a certain circumferential region of the cross-sectional surface of the channel bend 19 are adapted to the stepped end surface 3 of the guide piston 2. Ring seals 22 are located on both sides of the radial slots 9 and 10 of the guide piston 2.

I recirkulationsstillingen, i hvilken styrestemplet 2 35 med dets aftrappede endeflade 3 aflukker udløbsåbningen 18 fra blandekammeret, bliver den i tilførselsledningen 5 tilførte formstofkomponent uden nævneværdig strømningsmodstand fra ud-In the recirculating position, in which the control piston 2 35 with its stepped end surface 3 closes the outlet opening 18 from the mixing chamber, the plastic component supplied in the supply line 5 becomes without appreciable flow resistance from the discharge chamber.

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4 mundingsåbningen 11 via radialslidsen 9 umiddelbart ledt over i indmundingsåbningen 13 for returledningen 7. På grund af arrangementet med den flugtende tilførselsledning 5, udmundingsåbningen 11, radialslidsen 9, indmundingsåbningen 13 og 5 returledningen 7 er der ingen prelflader, på hvilke materialet af funktionselementerne på grund af højt tryk på formstof-komponenten og et eventuelt indhold af slibende fyldstofmateriale kan erodere.4, the orifice 11 via the radial slot 9 immediately leads into the orifice 13 for the return line 7. Due to the arrangement of the volatile supply line 5, the orifice 11, the radial slot 9, the orifice 13 and the return line 7, there are no baffles on which the material of the functional elements is due. of high pressure on the plastic component and any content of abrasive filler material can erode.

På analog måde ledes komponenten fra tilførselslednin-10 gen 6 via radialslidsen 10 ind i returledningen 8 i recirkulationsstillingen af styrestemplet 2. Indløbsåbningen 16 for sideledningen 15 er herved lukket af omkredsfladen på styrestemplet 2.In an analogous manner, the component from the supply line 6 is guided via the radial slot 10 into the return line 8 in the recirculation position of the guide piston 2. The inlet opening 16 for the side line 15 is thereby closed by the circumferential surface of the guide piston 2.

I blandestillingen, i hvilken styrestemplet 2 er truk-15 ket så langt tilbage, at det danner blandekammeret 17 og udmundingsåbningen 12 af tilførselsledningen 6 og indløbsåbningen 16 for sideledningen 15 er åbnet, er udmundingsåbningen 11 for tilførselsledningen 6 og returledningerne 7 og 8 lukkede, idet returledningen 8 lukkes af trinnet 21, der bibringer blan-20 dekammeret en ønsket, blandeeffekten forøgende formindskelse af blandekammervoluminet 17 i det umiddelbare indsprøjtningsområde .In the mixing position, in which the guide piston 2 is pulled so far back as to form the mixing chamber 17 and the orifice opening 12 of the supply line 6 and the inlet opening 16 of the lateral line 15 is opened, the orifice opening 11 of the supply line 6 and the return lines 7 and 8 is closed. the return line 8 is closed by the step 21 which provides the mixing chamber with a desired mixing effect increasing the mixing chamber volume 17 in the immediate injection region.

Fig. 4 og 5 viser et blandekammerhus 101 med et styrestempel 102 med plan endeflade 103 i recirkulationsstillingen, 25 i hvilken de fra blandekammerudløbsåbningen 118 fjernestlig-gende tilførsels- og returledninger 105 og 107 står i forbindelse med hinanden ved hjælp af en radialslids 109. De tilførsels- og returledninger 106 og 108, der er anbragt nærmest udgangsåbningen fra blandekammeret 118 er placeret over 30 hinanden og står i forbindelse ved hjælp af en i omkredsfladen af styrestemplet 102 udformet aksial recirkulationsnot 110. Ved denne udførelsesform ledes fortrinsvis den formstof-komponent, som indeholder abrasivt fyldstofmateriale, gennem tilførsels- og returledningerne 105 og 107, da der på 35 grund af den retliniede cirkulationsvej ikke findes strømnings-hindringer. I modsætning hertil danner den i og for sig kendte recirkulationsnot 110 en ugunstigere strømningsvej, da denFIG. 4 and 5 show a mixing chamber housing 101 with a guide piston 102 with flat end surface 103 in the recirculation position, 25 in which the supply and return lines 105 and 107, remote from the mixing chamber outlet opening 118, are connected to each other by means of a radial slot 109. and return lines 106 and 108 disposed closest to the exit opening of the mixing chamber 118 are positioned above each other and are connected by an axial recirculation groove 110 formed in the circumferential surface of the guide piston 102. In this embodiment, the plastic component containing abrasively is preferably guided. filler material, through the supply and return lines 105 and 107, as there are no flow barriers due to the rectilinear circulation path. In contrast, the recycle note 110 known per se forms a less favorable flow path as the

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5 på denne vej to gange ombøjede og under højt tryk transporterede formstofkomponent kan opvarmes utilladeligt og tillige er der risiko for, at den skarpe stråle kan medføre en overfladeerosion i bunden af recirkulationsnoten 110.5 on this road, twice-bent and high-pressure plastic component can be heated inadvertently and there is also a risk that the sharp jet may cause a surface erosion at the bottom of the recycle groove 110.

5 Tillige er der en risiko for, at fyldstofbestanddele som fx glasfibre, kan knække. I blandestillingen (ikke vist) er styrestemplet 102 trukket tilbage og åbner udmundingsåbningen 112 og indgangsåbningen 116, idet returledningen 107 og returledningen 105 lukkes af styrestemplets omkredsflade.5 There is also a risk that filler components such as glass fibers may break. In the mixing position (not shown), the guide piston 102 is retracted and opens the orifice opening 112 and the inlet opening 116, the return line 107 and the return line 105 being closed by the circumferential surface of the guide piston.

10 Samtidig bliver komponenten fra tilførselsledningen 105 ledt om i sideledningen 115 og indsprøjtet via indgangsåbningen 116 i blandekammeret. I blandestillingen er den vinkelret på blandekammeret tilsluttede kanalombøjning ligeledes åben, men efter afslutning af blandefasen og efter uddrivning af form-15 stofblandingen af blandekammeret ved hjælp af styrestemplet 102 renses den ved hjælp af stemplet 120.At the same time, the component from supply line 105 is routed into the lateral line 115 and injected via the inlet opening 116 into the mixing chamber. In the mixing position, the duct bending perpendicular to the mixing chamber is also open, but after completion of the mixing phase and after expulsion of the molding mixture of the mixing chamber by means of the piston 102, it is cleaned by means of the piston 120.

Fig. 6 og 7 viser et blandekammerhus 201 med et styrestempel 202 med plan endeflade 203 i recirkulationsstillingen, i hvilken tilførsels- og returledningerne 205 og 206, samt 20 207 og 208 står i forbindelse med hinanden ved hjælp af ra diale slidser 209 og 210.FIG. 6 and 7 show a mixing chamber housing 201 with a guide piston 202 with flat end surface 203 in the recirculation position, in which the supply and return lines 205 and 206, and 20 207 and 208 are connected to each other by means of radial slots 209 and 210.

I modsætning til de med hinanden flugtende placerede tilførsels- og returledninger 205 og 207 ligger tilførsels-og returledningerne 206 og 208 aksialt forskudt for hinanden, 25 således at efter tilbagetrækningen af styrestemplet 202 i blandestillingen lukkes tilførselsledningen 205 og returledningerne 207 og 208 af omkredsfladen på styrestemplet 202 og udmundingsåbningen 212 og den med tilførselsledningen 205 Via sideledningen 215 forbundne indgangsåbning 216 åbnes.In contrast to the flush-fed supply and return lines 205 and 207, the supply and return lines 206 and 208 are axially offset to each other, so that after the retraction of the control piston 202 in the mixing position, the supply line 205 and the return lines 207 and 208 are closed by the circumferential surface of the guide piston. 202 and the orifice opening 212 and the inlet port 216 connected to the supply line 205 are opened.

30 På grund af den aksiale forskydning af returledningen 208 kan der således med plan endeflade 203 på styrestemplet 202 i blandestillingen (ikke vist) opnås en aflukning af den nærmest blandekammerudgangsåbningen 218 beliggende returledning 208. Fortrinsvis er radialslidsen 210 forsynet med en ledefla-35 de 210', ved hjælp af hvilken den fra indførselsledningen 206 udstrømmende formstofkomponent kan afbøjes i retning mod returledningen 208.Thus, due to the axial displacement of the return line 208, with a flat end surface 203 on the control piston 202 in the mixing position (not shown), a closure of the return line 20 located closest to the mixing chamber outlet 218 can be obtained. Preferably, the radial slot 210 is provided with a guide surface 210. by which the plastic component flowing from the feed line 206 can be deflected in the direction of the return line 208.

66

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Fig. 8 og 9 viser et blandekammerhus 301 med et styrestempel 302 med plan endeflade 303 i blandestilling, i hvilken tilførselsladningerne 305 og 306 og returledningerne 307 og 308 er aflukket ved hjælp af styrestemplets 302 om-5 kredsflade. I denne udførelsesform er begge returledninger 307 og 308 arrangeret således at de flugter med tilførselsledninger 305 og 306 og i den (ikke viste) recirkulationsstilling indrettet til at blive forbundet med hinanden ved hjælp af radialslidser 309 og 310. Begge tilførselsledninger 10 305 og 306 er forsynet med sideledninger 315 og 323, der ved hjælp af indløbsåbninger 316 og 312 indmunder i blande-kammeret 317.FIG. 8 and 9 show a mixing chamber housing 301 with a guide piston 302 with flat end face 303 in the mixing position, in which the supply charges 305 and 306 and the return lines 307 and 308 are closed by the circumferential surface of the guide piston 302. In this embodiment, both return lines 307 and 308 are arranged so that they align with supply lines 305 and 306 and in the (not shown) recirculation position arranged to be connected to each other by radial slots 309 and 310. Both supply lines 10 305 and 306 are provided with side conduits 315 and 323 which open into the mixing chamber 317 by means of inlet openings 316 and 312.

De ovenfor beskrevne udføreIsesformer indeholder kun tilførselsledninger for to formstofkomponenter, men antallet 15 af tilførselsledninger med i flugt placerede returledninger og med fra tilførselsledningerne afgrenede sideledninger er ikke begrænset. Eksempelvis kan der i udførelseseksemplet ifølge fig. 8 og 9 også indsprøjtes fire formstofkomponenter gennem indgangsåbninger, der er placeret 90° forskudt fra hin-20 anden, i blandekammeret, idet indløbsåbningerne hver for sig står i forbindelse med en tilhørende tilførselsledning ved hjælp af en sideledning.The above-described embodiments contain only supply lines for two plastic components, but the number of 15 supply lines with flush return return lines and side lines branched from the supply lines is not limited. For example, in the embodiment of FIG. 8 and 9, four plastic components are also injected through inlet openings located 90 ° offset from each other into the mixing chamber, the inlet openings each communicating with an associated supply line by means of a lateral line.

Radialslidserne 9,10;109;209,210;309,310 er udformet som længdeslidser, der forløber midt gennem styrestemplet og 25 i dettes længderetning. Principielt er også andre former for gennemføringer egnet til dette formål, såsom fx indsnit fra omkredsfladen på tværs af styrestemplet, til i recirkulationsstilling af styrestemplet at sikre en uhindret gennemstrømning mellem tilførselsledning og returledning.The radial slots 9,10; 109; 209,210; 309,310 are formed as longitudinal slots extending midway through the guide piston and longitudinally thereof. In principle, other types of passages are also suitable for this purpose, such as, for example, incisions from the circumferential surface across the guide piston, in order to ensure in the recirculation position of the guide piston an unobstructed flow between supply line and return line.

30 En anden form for gennemføring kan bestå af en i om kredsfladen udformet ringnot, gennem hvilken komponenterne i recirkulationsstilling fra tilførselsledningen opdeles i to delstrømme, der ved indføring i returledningen igen forenes.Another type of feedthrough may consist of a ring groove formed around the circular surface through which the components in the recirculation position from the feed line are divided into two partial streams which, when introduced into the return line, are reunited.

3535

Claims

An apparatus for producing a preferably chemically reactive mixture of at least two plastic components and with a mixing chamber, in which supply lines for said components open and return lines, and which have an outlet opening for the plastic mixture and one in the mixing chamber. and retractable guide and displacement piston which in a recirculation position connect the supply and return lines of each component with each other and in the mixing position release the inlet to the mixing chamber, characterized in that the orifices (11,12; 111,112; 211,212) of the supply lines 15 (5, 6; 105,106; 205,206) are located in different radial planes in the mixing chamber (17; 117; 217) and at least one of the orifices (13; 113; 213) on one or more of the ones from the mixing chamber inlet opening (18; 118; 218) located return lines (7; 107; 207) are approximately in the same radial plane as the corresponding supply lines (5,105, 205), wherein at least one radial slot (9,10; 109,209) or a circular groove on the guide piston (2; 102; 202) in its recirculating position connects the supply and return lines 25 (5; 105; 205) located in the same radial plane and 7; 107; 207) and that from the inlet conduit (5; 105; 205) which is farthest from the mixing chamber outlet opening (18; 118; 218), a lateral conduit (15; 115; 215) is always branched into a plane in the mixing chamber (17; 117; 217) corresponding to the radial plane of the inlet conduit 30 (6; 106; 206) which is closest to the mixing chamber outlet (18; 118; 218), with the side conduit (15; 115; 215) in the recirculation position of the guide piston (2; 102; 202) is closed by its circumferential surface and in the mixing position of the guide piston (2/102; 202) is open at the same time as the supply line (6; closest to the mixing chamber outlet opening (18; 118; 218)). 106; 206).

Apparatus according to claim 1, characterized in that the inlet openings for the supply line (6), which is DK 162148 B closest to the outlet opening (18) of the mixing chamber, and its corresponding return line (8) are approximately in the same radial plane and in the recirculating position of the control piston (2). ) are connected to each other by means of a radial slot (10), and 5 that the end surface (3) of the guide piston (2) is stepped in such a way that in the mixing position of the control piston (2) the nearest opening of the mixing chamber (18) is located. supply line (6) and side line (15) simultaneously open and return lines (7,8) closed.

Apparatus according to claim 2, characterized in that a duct bending (19) having a cross-sectional shape corresponding to the stepped end surface (3) of the guide piston (2) is connected to the mixing chamber (17) at a right angle. in such a way that the outlet opening (18) of the mixing chamber in the recirculation position is flush closed by means of the stepped end surface (3) of the guide piston (2) and forms a fully closed channel bend (19) in which a piston ( 20), whose cross-sectional shape corresponds to the channel bend (19), is movable back and forth.

Apparatus according to claim 1, 2 or 3, characterized in that the inlet openings for the supply line (106) which is closest to the outlet opening (118) of the mixing chamber and its associated return line (108) are located in 25 different radial planes and in the recirculation position of the guide piston (102) is connected to each other by means of a recirculation groove (110) known per se in the circumferential surface of the guide piston (102).

Apparatus according to claim 1, characterized in that the orifice openings for the supply line (206) which is located closest to the outlet opening (218) of the mixing chamber and its associated return line (208) are located in different but closely adjacent radial planes. and in the recirculation position of the guide piston (202) is connected 35 by means of a corresponding radial slot (210), the axial displacement between the supply line (206) and the return line (208) being such that with a flat end surface · (203) of the control plunger (202), the supply opening (212) located near the outlet opening (218) of the mixing chamber (212) and the lateral line (215) and the return lines (207,208) are closed simultaneously.

Apparatus according to any one of claims 1 to 5 for producing a preferably chemically reactive mixture of three or more plastic components, characterized in that the orifices for the supply and return lines for the third of each of the following components are also located. approximately in the same radial plane but axially displaced relative to the orifice openings for the other supply and return lines and connected to each other by corresponding radial slots or annular grooves in the guide piston in its recirculation position, and that from the third and subsequent supply lines 15 is a branch line, all side lines opening in the same radial plane as the supply line located closest to the outlet opening of the mixing chamber.

Apparatus for producing a preferably chemically-reactive mixture of at least two plastic components and with a mixing chamber, in which feed lines for the individual components open and return lines, and which have an outlet opening for the plastic mixture and one in the mixing chamber. and retractable control and displacement piston which in a recirculation position connects the supply and return lines of each component with each other and releases in the mixing position the inlet to the mixing chamber, characterized in that the orifice openings for the supply and return lines (305,306; 307,308) are approximately located in the same radial plane, however, with respect to the second and subsequent supply and return lines with an axial displacement, and in recirculation position of the guide piston (302) connected to each other by means of corresponding radial slots (309,310) or circular grooves in the guide piston (302 ), and that from each supply line (305,306) is branched a side line (315,323) which opens into the mixing chamber (317) in a radial plane located between the outlet opening (318) of the mixing chamber and the supply line (306) which is closest to the mixing chamber. B the outlet opening of the chamber, in the mixing position there is disconnected between the corresponding supply and return lines (305,306; 307,308) and at the same time is opened for the inlets from the side lines (315,323) in the mixing chamber (317).

Apparatus according to any one of claims 1-7, characterized in that each side conduit (15; 115; 215; 315; 323) is controllable via a pressure reducing device depending on the control piston (2; 102; 202; 302). position in such a way that the side cables are fully open only in the mixing position of the guide piston.

Apparatus according to any one of claims 1-8, characterized in that at least the supply and return lines (5; 105; 205) located at the outlet opening (18; 118; 218; 318) 15 305 and 7; 107; 207; 307), the corresponding supply and return lines are positioned so that they align with each other and the radial slots have a width at least equal to the width of the flow cross-sections of the supply and return lines 20.

Apparatus according to any one of claims 1-9, characterized in that axially on both sides of the radial slots (9,10; 109; 209; 309,310) or the circumferential grooves in the guide piston (2; 102; 202; 302 ) are provided with sealing rings (22; 122; 222; 322).