DE2815460B2 - Mixing device for multi-component plastics, especially polyurethane - Google Patents

Description

The invention relates to a mixing device for multicomponent plastics, in particular polyurethane, with a mixing chamber that has inlet openings for the individual components and an outlet opening for the component mixture, as well as with a control element that moves between a position that leaves the inlet openings open and a position that closes the inlet openings to the mixing chamber - and can be moved forward, the control member being designed as a hollow piston containing an independently controllable ejection piston, the end face of which facing the mixing chamber forms the mixing chamber wall opposite the outlet opening, the outlet opening being followed by an outlet pipe with a smaller cross-section than the mixing chamber cross-section through which the with the same cross-section designed ejector piston can be moved therethrough. 4 ^r >

In a known mixing device of the type mentioned above, the ejection piston serves as a Cleaning piston for the outlet opening and the outlet pipe (DE-OS 25 50 334).

With differently designed mixing devices for "> It is known in principle for multi-component plastics to have a piston in the outlet area Make throttling of the mixture (DE-OS 24 13 337 and 26 12 812).

In such a mixing device in ■> ■> In many cases, sufficient mixing results can be achieved because the outlet opening is smaller Has cross section than the mixing chamber, whereby the mixing result is positively influenced. If higher Requirements are placed on the mixing quality, w> i.e. if, for example, in open forms Manufacture of high-quality shoe soles made of polyurethane or similar parts should be filled - this is currently done with mixing devices with a mechanical stirrer, which operate in the low-pressure process ·> ■> work - then the mixing result is often not sufficient.

The invention is based on the object of providing a mixing device of the type mentioned at the beginning create, through which the mixing quality is improved, d. H. in which very good mixing results are achieved even with components that are difficult to mix processed and if necessary filled into open forms.

This object is achieved according to the invention in that the ejection piston for throttling the Inlet of the component mixture to the outlet opening on this with adjustable axial distance is approachable

The mixing device according to the invention is not only a high-pressure mixing device, which is characterized by the Movement of the two pistons can be mechanically forced cleaning, but by the movement of the ejector piston the outlet opening can be throttled accordingly, whereby the mixing process as desired being affected. The setting of the outlet cross-section can depending on the type of component used and taking into account the one to be manufactured Product.

In the following the invention is explained with reference to the drawing on the basis of various exemplary embodiments explained in more detail. It shows

F i g. 1 shows a longitudinal section through an embodiment according to the invention;

FIG. 2 shows a cross section along the line AA of FIG.

F i g. 3 shows a cross section along the line AA through another embodiment with a different hollow piston cross section;

F i g. 4 one of the F i g. 1 corresponding section through another embodiment; and

F i g. 5 shows a section along the line B-B of FIG . 4th

The mixing device shown in the drawing consists of a mixing chamber housing 1 in which a Mixing chamber 2 is formed. An outlet pipe 3 connects to the mixing chamber 2. The outlet opening the mixing chamber 2 is denoted by 15. Flow lines lead into the mixing chamber via inlet openings 4 and 5.

In the mixing chamber 2, a hollow piston 6 is arranged, which via a hydraulic piston 7 back and is moveable. In the hollow piston there are return grooves 8 and 9 for connection to return ducts 10 and 11 formed in the return or closed position, not shown. The return grooves 8 and 9 run helically, as the return channels 10 and 11 in relation to the flow lines leading to the Inlet openings 4 and 5 lead, are arranged offset. Sealing grooves 12 are above and below the Return grooves provided.

An ejector piston 13 can be moved back and forth in the hollow piston, which piston moves via a hydraulic piston 14 is controllable. This discharge piston 13 is the same size as the outlet pipe 3 and over aligns with this.

The embodiment according to FIG. 2 has a hollow piston 6 with a circular cross section.

The embodiment according to FIG. 3 has a hollow piston 6 'with an elliptical cross section equipped.

The embodiment of Figures 4 and 5 is with a Hollow piston 6 ″ elongated in cross section is provided. When looking at FIGS. 4 and 5, it becomes clear that that the inlet openings 4 and 5 in the area of the elongated side walls of the mixing chamber 2 lie and so a relatively small distance

have from each other. With regard to the outlet pipe 3 or the ejection piston 13, they are laterally offset. that the ejection piston 13 can be controlled to further narrow the outlet opening 15.

In the illustration of FIG. 4 and 5, no return grooves and corresponding lines have been illustrated, although such return means g also in the embodiment of Figures 4 and 5 corresponding to the illustration of R i. 1 to 3 can be provided.

During operation, there is a mixture of those injected with pressure through the openings 4 and 5 Components in de? Mixing chamber 2, as the hollow piston 6 allows entry. The ejector piston 13

can be used to regulate the .. cross-section of the Outlet opening 15 are controlled. When a mixing process or a shot is to be ended, will the hollow piston moves downwards so that the inlet openings 4 and 5 are closed, wherein at the same time a mechanical forced cleaning of the mixing chamber 2 by pushing out any residues he follows. The ejector piston 13 then provides a final cleaning by moving through the Outlet pipe 3. The ejection piston 13 can thus fulfill two functions, namely a throttle function in the Area of the outlet opening 15 during the mixing process and a cleaning function after completion of the mixing process.

For this purpose 2 sheets of drawings

Claims (1)

Claim: 28! 5 Mixing device for multi-component plastics, in particular polyurethane, with a mixing chamber, the inlet openings for the individual components and an outlet opening for the Has component mixture, as well as with a control member, which is between one of the inlet openings leaving open position and a position closing off the inlet openings to the mixing chamber is reciprocable, wherein the control member as an independently controllable ejection piston containing hollow piston is formed whose end face facing the mixing chamber that of the outlet opening opposite mixing chamber wall forms, with a Outlet pipe with a smaller cross-section than the mixing chamber cross-section, through which the ejection piston with the same cross-section can be moved through, characterized in that, that the ejection piston (13) to throttle the inflow of the component mixture to the outlet opening (15) to this with adjustable axial distance can be approached. 25th