DE102018214410A1 - Mixing device and method for forming a component - Google Patents

Abstract

The invention relates to a mixing device for mixing and dispensing at least two, preferably three, reacting components. The mixing device comprises a mixing chamber for mixing reactive components, the mixing chamber having an outlet opening, and injection devices which are each configured to inject one component into the mixing chamber, the amount of the respective component applied by at least one of the injection devices being changeable.

Description

Technical field

The invention relates to a mixing device for mixing and dispensing at least two, preferably three, reacting components. The invention further relates to a method for forming a component, in particular a fiber composite component.

State of the art

The DE 10 2007 023 239 A1 describes a method and a device for producing a polyurethane from at least two liquid starting components, the starting components coming from opposite directions being injected into a mixing chamber under high pressure, mixed with one another, brought to a chemical reaction and ejected from the outlet opening of the mixing chamber. The mixing device, also known as the mixing head, is characterized in that the injection nozzles are directed against an opposing baffle wall of the mixing chamber and that the extensions of the injection nozzles intended in the direction of the baffle wall penetrate the baffle wall at a distance B from one another.

Although the mixing device mentioned has proven itself, it is shown that the cycle time, in particular in the case of workpieces of comparatively large dimensions, depends more clearly on the hardening time of the material last introduced into a mold. This last injected material also takes the full curing time, although other portions of the workpiece to be formed that are distant from the gate area have already cured. These areas of the workpiece to be formed, which are close to the gate, then specify the cycle time.

Subject of the invention

One of the objects of the invention is to provide a mixing device and a method with which the cycle time can be shortened and thus the productivity can be further increased.

The subject matter of claim 1 provides a corresponding mixing device. Further preferred embodiments of the mixing device are listed in the dependent claims and / or described below. The invention further relates to a method for forming a component, in particular a fiber composite component. Within the scope of the method, features of individual claims or the forms described below can each be used independently. Conversely, the mixing device can be set up to use individual method features, which are described in particular in the method claims or described below, independently of one another.

According to the invention, a mixing device is provided which has: a mixing chamber for mixing reactive components, the mixing chamber having an outlet opening, injection devices which are set up to inject one component each into the mixing chamber. It is further provided that the quantity of the respective component that is applied by at least one of the injection devices can be changed.

The mixing device has the advantage, among other things, that the use of the mixing device can be adapted to the manufacturing component to a certain extent and the mixing device thus has a high degree of flexibility. In addition, a resource-saving process is made possible.

Furthermore, it can be provided that the mixing device has a first injection device, a second injection device and a third injection device, the amount applied of the respective component of the first injection device and the second injection device being changeable relative to one another.

Thus, three components can be mixed and the amount of the first injector and the second injector applied during the mixing process can be varied relative to one another.

In a further embodiment it is provided that the first injection device and the second injection device are set up to inject a polyol into the mixing chamber, and the third injection device is set up to inject isocyanate, in particular di-isocyanate, into the mixing chamber. The mixing device thus has great variability.

At least one of the injection devices (preferably the aforementioned first and second injection device) can have a throttling needle for changing the nozzle cross section. In this context, it is particularly provided that the discharge rate is varied by means of one or more high-pressure pumps. Since the pressure depends on the discharge rate and the outlet cross-section, if the discharge rate is varied, the cross-section can be adjusted accordingly in order to keep the pressure constant (constant pressure regulation). The cross-sectional area of the nozzle is changed when the throttling needle (needle) is adjusted. Thus, this embodiment provides a practical solution.

It can be provided that the outlet openings of the injection devices are arranged at the same or substantially the same angle relative to an axis of the mixing chamber. A compact design of the mixing device can thus be realized.

It is preferred that at least one of the injection devices has an actuator with a servo motor. This actuator can be used to move the aforementioned throttling needle. A precise, variable adjustment is made possible with a servo motor.

An actuating piston can be accommodated in the mixing chamber, the actuating piston being movable relative to the outlet opening. In particular, the movement of the actuating piston can be used to switch between an operating position in which the components can be introduced into the mixing chamber and a rest position. It is thus possible to switch the mixing process on or off.

The injection devices can be set up to inject the respective component at an angle to the axial direction of the mixing chamber, it being preferred that the angle deviate from a 90 ° angle.

A control device is preferably provided, which is set up to control the mixing device in such a way that the pressure is kept constant when the amount of the respective component is increased or decreased. In particular, the quantity / discharge rate is varied by means of one or more high-pressure pumps on the metering machine. Since the pressure depends on the discharge rate and the outlet cross-section, if the discharge rate is varied, the cross-section is adjusted accordingly in order to keep the pressure constant (constant pressure regulation). The cross-sectional area of the nozzle is changed, for example, by adjusting a throttle needle.

Furthermore, the invention relates to a device for producing a component, in particular a fiber composite component, the device having a mixing device according to one of the preceding aspects, the device further comprising a tool having a cavity. The mixing device can be set up to introduce mixed components into the cavity. The advantages of the mixing device already explained can thus be integrated into the device for producing a component.

The invention further relates to a method. The method for forming a component, in particular a fiber composite component, is intended to mix reactive components in a mixing chamber and to inject a component into a cavity of a tool, the amount of at least one of the components introduced into the mixing chamber being changed.

It is preferred that a first component, a second component and a third component are injected into the mixing chamber, the amount of the first and second components being changed relative to one another, in particular during the injection of the first and second components. The composition of the three-component material can thus be adapted to the respective circumstances, depending on the stage of the process.

It is preferred that different reactive polyols and isocyanate, in particular di-isocyanate, are injected into the mixing chamber, the amount of the polyols being changed relative to one another.

It is further preferred that the amount is changed continuously. Thus, the composition of the mixed material can be continuously adjusted.

It can further be provided that the pressure of the components injected into the mixing chamber is kept constant. In this way, a high quality manufacturing result is guaranteed.

list of figures

• 1 shows a perspective view of an embodiment of a mixing device according to the invention.
• 2 shows a sectional view of the in 1 shown mixing device.

Detailed description of the preferred embodiment

A preferred embodiment of a mixing device according to the invention, with which polyurethane is produced from several components, will now be illustrated with the aid of the accompanying drawings. In the mixing device, the particularly liquid components are mixed with one another at high pressure in a mixing chamber and discharged from an outlet opening of the mixing chamber, the polyurethane prepared or produced in this way preferably being introduced into a cavity of a tool.

Modifications of certain individual features of the embodiment described below can each be combined with other features of the Embodiment can be combined to form further variants of the invention. Although the embodiment described below is presented purely by way of example, individual features of the embodiments can also be used to characterize the invention.

The mixing device 1 comprises a first plate 2 as well as one from the first plate 2 spaced apart second plate 3 , Between the plates 2 . 3 is a mixed body 10 added to a mixing chamber 11 includes. The mixing chamber 11 is in the area of an outlet opening 12 opened so one in the mixing chamber 11 mixed reaction mixture from the outlet opening 12 can be applied. The mixing body 10 is in the area of the outlet opening 12 designed for attachment to a tool.

In the mixing chamber 11 is an actuating piston 13 added, which is movable in the axial direction. The actuating piston 13 can be moved at the beginning of the mixing process to start the mixing process (movement from a rest position to an operating position). The mixing process is reversed by moving the actuating piston 13 ended from an operating position to a rest position.

To the mixing body 10 around are a first injector 20 , a second injector 30 and a third injection device (in 1 through the mixing body 10 covered) provided, each with the mixing body 10 are connected. Relative to the axis of the mixing chamber 11 the injection devices are arranged at a respective angle of 120 ° to one another.

The first injector 20 includes an actuator 21 , The actuator 21 is by a servo motor 22 driven, the servo motor 22 in the longitudinal direction of the mixing device 1 is arranged. The actuator 21 serves a nozzle cartridge 23 to operate, the nozzle cartridge 23 a choke needle 23a with which the nozzle cross-section for introducing a component through the first injection device 20 can be changed.

For supplying a first material (polyol) through the first injection device 20 is a feed line 25 intended. There is also a return line 26 intended.

Through the feed line 25 the first material passes through the holes in the nozzle cartridge 23 and from there through the nozzle into the mixing chamber 11 , By adjusting the nozzle needle 23a the injector 20 , which can be driven manually or by motor, the pressure of the first material is adjusted by changing the outlet cross section in the event of a change in the discharge capacity by means of a high-pressure pump used for this purpose to convey the first material.

With the (servo) motorized adjustment of the throttle needle 23a the discharge performance itself is not changed. The discharge rate is varied using the high pressure pumps on the dosing machine. Because the pressure of the mixing device 10 depends on the discharge rate and the outlet cross-section, if the discharge rate is to be varied, the cross-section is also adjusted accordingly in order to keep the pressure constant (constant pressure control). The cross-sectional area of the nozzle is changed when the throttle needle is adjusted 23a ,

The second injector 30 is similar to the first injector 20 constructed, and in particular comprises an actuator 31 as well as the actuator 31 actuating servo motor 32 , By the actuator 31 similar to the first injector 20 , a throttle needle (not shown) operated to change a nozzle cross section.

To supply a second material (polyol) through the second injector 30 is a feed line 35 provided the supply line in 1 is shown. There is also a return line 36 intended. The arrangement and / or configuration of the feed line 35 and the return line 36 is similar to that of the feed line 25 and the return line 26 the first injector 20 ,

Through the feed line 35 the second material passes laterally through holes in the nozzle cartridge of the second injection device 30 and from there through the nozzle into the mixing chamber 11 , By adjusting the nozzle needle of the second injection device 30 which can be driven manually or by motor, the pressure of the second material is adjusted by changing the outlet cross section in the event of a change in the discharge capacity by means of a high-pressure pump used for this purpose to convey the first material.

In 1 becomes the third injector through the mixing body 10 covered. However, the third injection device is designed similarly to the first and second injection device, and in particular comprises a feed line 45 , a return line 46 as well as a nozzle cartridge. The third injection device is used to inject a third material, in particular di-isocyanate, into the mixing chamber, so that it is mixed with the first and second material.

The mixing device 1 is intended to be used in operation in the mixing device 1 to introduce mixed polyurethane into the cavity of a tool, it being possible, for example, to insert a fiber blank into the cavity beforehand. In operation, a di-isocyanate component and two polyol components are mixed in opposite directions and continuously in the course of counter-metering, one of the polyol components being more reactive than the second polyol component.

During the mixing of the polyols with the di-isocyanate, the relative ratio of the polyols to one another is changed. In particular, in the course of the mixing process, the amount of the polyol which can be activated more quickly is increased, whereas the amount of the less reactive polyol is correspondingly reduced.

It is thus possible to achieve faster curing of the polyurethane in a region close to the gate, which reduces the overall curing time.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102007023239 A1 [0002]

Claims (15)

Mixing device (1) comprising a mixing chamber (11) for mixing reactive components, the mixing chamber (11) having an outlet opening (12), thereby injecting devices (20, 30) which are set up to inject one component into the mixing chamber characterized in that the quantity of the respective component applied by at least one of the injection devices can be changed. Mixing device (1) according to Claim 1 , characterized in that the mixing device has a first injection device (20), a second injection device (30) and a third injection device, the amount applied of the respective component of the first injection device and the second injection device being changeable relative to one another. Mixing device (1) according to Claim 2 , characterized in that the first injection device (20) and the second injection device (30) are set up to inject a polyol into the mixing chamber, and the third injection device is set up to inject isocyanate, in particular di-isocyanate, into the mixing chamber. Mixing device (1) according to one of the preceding claims, characterized in that at least one of the injection devices has a throttle needle (23a) for changing the nozzle cross section. Mixing device (1) according to one of the Claims 2 - 4 , characterized in that outlet openings of the injection devices (20; 30), relative to an axis of the mixing chamber (1), are arranged at the same or substantially the same angle. Mixing device (1) according to one of the preceding claims, characterized in that at least one of the injection devices (20; 30) has an actuator (21, 31, 41) with a servo motor (22, 32, 42). Mixing device (1) according to one of the preceding claims, characterized in that an adjusting piston (13) is accommodated in the mixing chamber (11) and can be moved relative to the outlet opening (12). Mixing device (1) according to one of the preceding claims, characterized in that the injection devices are set up to inject the respective component at an angle to the axial direction of the mixing chamber (11). Mixing device (1) according to one of the preceding claims, characterized by a control device which is set up to control the mixing device in such a way that the pressure is kept constant when the amount of the respective component is increased or decreased. Device for producing a component, in particular a fiber composite component, comprising a mixing device according to one of the preceding claims and a tool having a cavity, the mixing device being set up to introduce mixed components into the cavity. Method for forming a component, in particular a fiber composite component, wherein reactive components are mixed in a mixing chamber (11) and injected into a cavity of a tool to form a component, wherein the amount of at least one of the components introduced into the mixing chamber is changed. Procedure according to Claim 11 , characterized in that a first component, a second component and a third component are injected into the mixing chamber (11), the amount of the first and second components being changed relative to one another. Method according to one of the Claims 11 - 12 , characterized in that different reactive polyols and isocyanate, in particular di-isocyanate, are injected into the mixing chamber (11), the amount of the polyols being changed relative to one another. Method according to one of the Claims 11 - 13 , characterized in that the amount is continuously changed. Method according to one of the Claims 11 - 14 , characterized in that the pressure of the components injected into the mixing chamber is kept constant.

Images