EP3372305A1 - Low pressure mixing system and method for liquid and pasty mixed components with gaseous and solid mixed components, in continuous operation and individual mixed portions in any outlet position - Google Patents

Abstract

Low-pressure mixer also for hardenable mixtures of liquid, pasty with gaseous and solid components, in which a slanted rotor axis with mixing chamber centerline and generatrices of a conical rotor intersect in a Taumelpunkte (T). The rotor performs a tumbling motion in addition to its own rotation. At the same relative speed of rotor and tumbling motion to the mixing chamber wall solid components can be mixed with. Impurities in the mixing components do not affect the function of the mixing process. The mixing process allows any discharge direction of the mixture by the emptying process.

Description

In the production of foams after the high-pressure mixing system, mixing components are injected at high pressure into a mixing chamber whose jets penetrate one another and thus form a mixture. Impurities in the mixing components lead to blockage of the mixing nozzles and thus to an undefined mixing ratio.

For curable mixtures deposits are built up on the mixing chamber wall which is removed at a mixing interruption by a piston stroke of the mixing chamber wall.

In a low pressure mixing system, the mixing components are mixed together in a mixing chamber by a rotor. The rotor carries out a circulation movement in addition to its own rotation.

If the cured foams are used for insulation, it is possible to save about 50% of the mixing components with the same insulation values in the case of low-pressure systems due to their lower foam weight and significantly better λ values. In addition, the useful volume to be insulated is increased or the outer dimensions of the insulation are reduced. Also impurities in the mixing components lead to no disturbance.

Due to the low energy input during low-pressure mixing, this is also suitable for adding pentane. This again leads to an improvement of the λ values.

Low pressure mixing head EP2271421 is designed for vertical material cutting and designed for continuous operation. Due to the eccentric bearing and the conical shape of the rotor, the ratio of the relative velocities along the contact line of rotor and eccentric movement changes.

The aim of the invention is in addition to the production of high-quality foams and mixtures with liquid and pasty mixing components with solid and gaseous components, regardless of position, in continuous operation and for mixing individual portions.

This object is achieved by a low-pressure mixer according to claim 1 to 4 and mixing method according to claim 5 to 8.

The positional independence is achieved by the use of a displacement medium (e.g., air), with interrupted mixing components supply and ongoing rotor and tumble motion

In the storage area, the storage can be kept free of the mixing components by an overpressure at a vertical outlet upwards.

When mixing with solid mixing components, the relative velocity along the line of contact from the rotational movement of the rotor and the pigeon movement should be the same. As a result, a pressure is built up by the wedge shape.

sein damit die Berührlinie frei von festen Mischkomponenten gehalten wird.The ratio of rotor speed n _R to the speed of the tumble motion n _T should $${\mathrm{n}}_{\mathrm{R}}={\mathrm{d}}_{\mathrm{M}}/{\mathrm{d}}_{\mathrm{R}}\times {\mathrm{n}}_{\mathrm{T}}$$

so that the contact line is kept free of solid mixing components.

(Fig.1) mit A

als Mischbereich

B

als Taumelpunkt

C

als Lagerbereich

$$\mathrm{B}/\mathrm{A}\ne \mathrm{\infty }$$

This is achieved by a conical shape of rotor and mixing chamber in which the center lines of rotor axis and mixing chamber and the generatrices of the rotor intersects in a point, the wobble point.

(Fig.1) with A

as a mixing area

B

as a stumbling block

C

as storage area

$$\mathrm{B}/\mathrm{A}\ne \mathrm{\infty }$$

The mixing takes place by a vortex formation, which changes its position by the tumbling motion and results in a homogeneous mixture due to the adhesion to the mixing chamber and rotor surface.

Other types of rotor are possible but with significantly higher rotor speeds and higher energy contribution.

If the mixture is to be introduced through a small opening into a cavity over a distance, then the exit jet should have a round shape as possible. This can be achieved for example by a spherical shape in which the end of the mixing chamber and rotor is the same. ( Fig. 2 )

By Tangentenhilfspunkte (h1, h2, etc.) which run along the rotor center line continuously this shape can be formed which has good mixing results. For solid mixed components this form is not suitable.

In the case of the crowned shape, the rotor's speed and mixing chamber's diameter mean that the rotor's speed should be significantly higher.

When admixing gaseous mixed components, it is possible, for example in the case of CO _{2, to} reduce the ignitability of the foam.

The wobble point may also be behind the drive opening in front of the outlet opening.

If the wobble point in front of the outlet opening creates a squat design.

If the wobble point in the drive area or behind it creates a slim design with which can be immersed through small openings in a cavity and the foaming begins at the rearmost position and is moved by a displacement of the position of the mixer (eg for foaming body parts).

As a result, the displaced air can escape through the opening and air bubbles in the foam can be prevented.

View A from Fig. 1 and Fig. 2 shows the different shape in the Austrittsqerschnitt conical and spherical rotor with the effect on the outlet jet cross section.

Fig. 3 shows mixing component connections for the different mix variants and possible execution of the shutdown mode.

Inlet D for higher viscosity mixed components optionally with admixture of solid and / or gaseous mixed components.

Inlet F for low-viscosity mixed components with gaseous mixed components.

Fig. 4 shows with connection F a possibility to keep the drive area free of mixing components.

Port P1a shows a possibility with a gaseous displacement medium and a pressure accumulator volume V in port G to empty the contents of the mixing chamber at the end of a mixture.

Port P2b one way with a liquid displacer and a pressure accumulator volume V in port G to empty the contents of the mixing chamber at the end of a mixture.

Fig. 5 shows an embodiment of a mixer with a feed region, a mixing region and an outlet region with a plurality of outlet openings in which the material in the outlet region V2 consists of non-stick material.

Claims (10)

Low-pressure mixing system and mixing method of liquid or pasty with gaseous and solid mixing components with a mixing chamber, with at least two inlet openings and at least one outlet opening in which an inclined rotor mixes the components to be mixed by its rotational speed and performs a tumbling motion about a Taumelpunkt next to its own revolution and flows through the mixing chamber of the components to be mixed is characterized in that the tumbling point is outside the mixing chamber and the intersection or the smallest distance from the mixing chamber center line and the rotor center line. Low-pressure mixing system according to claim 1, characterized in that the material of the rotor and mixing chamber has at least one of a mixing component good adhesion. Low pressure mixing system according to claim 1, characterized in that in the mixing mode, the rotor shape and the mixing chamber shape in the mixing region has a continuous contact line. Low-pressure mixing system according to claim 1, characterized in that the outlet has the smallest diameter of the mixing chamber. Mixing method according to claim 1, characterized in that the storage area has an overpressure whose size is dependent on the position of the outlet opening and the flow losses in the mixing chamber. Mixing method according to claim 5, characterized in that at the end of the mixing process with interrupted Mischkomponententufuhr and ongoing wobble and rotor movement a displacement medium (eg., Air) pressure and speed-dependent emptied the mixing chamber contents. Mixing method according to claim 5, characterized in that the displacement medium storage is tuned to the volume of the mixing chamber volume. Mixing method according to claim 5, characterized in that the outlet direction of the mixture can be adjusted by the pressure in the displacement medium storage. Mixing method according to claim 5, characterized in that Depending on the viscosity of the mixture and the local rotational speed by the wedge-shaped course on both sides of the contact line, a pressure is built up. Mixing method according to claim 9, characterized in that with a tapered shape of the rotor and the mixing chamber along the contact line to the outlet towards the pressure decreases and thereby supports a flow in the near-touch material to the outlet towards.

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