DE1068219B - Thin film evaporator - Google Patents

Description

F 26402 IVc / 12a

REGISTRATION DAYS AUGUST 14, 1958

NOTICE LOGIN AND ISSUE OF THE EDITORIAL:

NOVEMBER 5, 1959

The invention relates to a thin film evaporator with a stirrer for spreading the to be treated Liquid on a heated wall and with a built-in condenser, the condensation surfaces of which are at least partially the evaporation surfaces are opposite at the same axial height.

With the thin-film evaporators of this known type there is a risk that parts during the evaporation of the film detach themselves from the wall and in the form of foam droplets or mist from the steam stream Capacitor are fed. Although the use of the usual agitator blades is already a considerable one Improvement of the film and deposition ratios compared to the simple free-fall evaporator, it is still one important task of completely preventing the drops from spraying off, as these should concentrate as much as possible Dilute the residue again or contaminate the distillate.

The danger that such unevaporated liquid ao particles are fed to the capacitor, is particularly present when the capacitor is in is arranged of the type described above. With this type of construction, however, there is also a considerable amount Reduction in the effectiveness of the condenser. when heat rays from the evaporation surfaces can hit the condensation surfaces. The performance of the evaporator surface is also reduced Heat radiation, whereby the heat requirement increases unfavorably.

It has now been found that an improvement in the separation of droplets and at the same time a prevention the heat radiation occurs between evaporation and condensation surfaces if according to the invention the edges facing the evaporation surface of the Rühnverksflügel compared to the edges facing the condensation surface in the direction of rotation run backwards and the wings overlap like a blind at such a distance that a A view from anywhere on the evaporator surface to one of the condenser surfaces is prevented. the Agitator blades can be designed as articulated wipers or as agitator blades rigidly attached to the agitator and be arcuately curved so that the rotating flow of the inside of the evaporator body rising vapor is aerodynamically improved. The blade-shaped agitator blades are on their long sides incised radially, and the lobes between the incisions are out of the plane of the wing bent out. The lobes form individual helical elements for spreading the Liquid, the edges of which are close to the evaporator inner wall stroke past or drag on it. Each wing has a larger number of them Thin film evaporator

Applicant:

Paint factories Bayer Aktiengesellschaft, Leverkusen-Bayerwerk

Dipl.-Ing. Rudolf Schneider, Krefeld-Uerdingen,

Emil Gruber, Zurich (Switzerland),

Dipl.-Ing. Werner Strittmatter, Butzbach (Hess.), And Dipl.-Ing. Dieter Pinkwart, Cologne-Mülheim, have been named as inventors

Lobes that are all bent out of the plane of the wing in the same direction. To now the dwell time To shorten or lengthen the liquid in the vaporizer, you can use the lobes of a rühifflügel or alternately the adjacent impeller are tilted so that they move the liquid down or swipe up. If a long dwell time is desired, all flaps are tilted upwards, so that they convey against the liquid running down as a result of gravity. To shorten it the dwell time, all flaps are placed at an angle downwards.

There are the most varied combinations of wiping partly upwards and partly downwards Flaps possible. There are thin film evaporators with louvre-like internals known; these serve however, themselves as capacitor surfaces and have no wiping effect. There are also built-in blinds known, which serve as spray filters. These internals also have no wiping effect and do not give complete protection against radiation. Due to the blind-like close together according to the invention The vane arranged on the agitator simplifies the evaporator construction with built-in condenser; it saves space, reducing the distance between the evaporation surface and the condensate surface can be kept smaller, which is especially useful for high vacuum distillation and molecular distillations is beneficial. Due to the closer assembly and the saving of a special radiation protection the construction becomes more economical.

Exemplary embodiments of the subject matter of the invention are shown schematically in the drawing. Here in shows

SW 647 / Ϊ71

Fig. 1 a longitudinal section through the evaporator with built-in condenser and with hinged, impellers acting as wipers and

Fig. 2 shows a cross section through this evaporator according to 2-2; in the

Fig. 3 and 4 is an evaporator with rigid agitator blades shown in cross section;

Fig. 5 shows a piece of an impeller edge, seen in the radial direction towards the axis;

Fig. 6 illustrates part of an evaporator cross-section with agitator blades in the shape of eccentric mounted wiper arms formed angled wings.

In Fig. 1, 1 means a feed for the liquid to be evaporated, 2 a liquid distributor- ^ 5 ring, 3 an evaporator tank, 4 a heating jacket of the evaporator tank, 5 an outlet for the not evaporated residue, 6 an outlet nozzle for the non-condensable gases, which is connected to the (not shown) Vacuum device is connected,

On the shaft 7 sit concentrically attached rings 8, which are connected to stiffening rods 8a are and carry the movable about pin 9 agitator blades in the form of wipers 10; Brush these impellers the inside of the container 3 and thus distribute the liquid film running down there. At the At the end of the shaft there is one designed as a race 11 Sliding surface that slides on the inner surface of the container and ensures that the shaft is centered, perform.

As can be seen in Fig. 2, the wipers 10 are arranged like louvers so that the on the surface of rotation sliding edges of the wiper, from the shaft center point 16 as well as from any point of the As seen from the capacitor 12, lie hidden behind the edge of the respective next following wiper.

By this arrangement it is achieved that drops spraying off the wall with a high degree of certainty detected by the next following wiper and returned to the wall by centrifugal force will. Inside the cylindrical thin-film evaporator a capacitor 12 is arranged. Due to the blind-like overlapping arrangement of the wipers there is direct heat radiation from the heated evaporator surface to the cooled condenser surface prevents and thus not only the thermal efficiency, but also the volume output at the same time of the evaporator is increased and the heat consumption is reduced. To also have a heat transfer To avoid reflection on the wings, these can be done with a surface layer that does not radiate warmly be provided. With 16 the supply pipe for the cooling medium is designated, with 13 the derivation: the condensate flowing down along the condenser 12 is passed through the collecting line 14a provided pipe 14 derived.

In Fig. 3 and 4 cross sections are illustrated through an evaporator, the blades 17 rigidly on Agitator are attached.

The wings 10 and 17 have tabs 18 on their outer edges, which between the incisions 19 are bent out of the plane of the wings 10 and 17, so that they are helically curved, small Form blades, the edges of which brush past the inner wall 3.

In Fig. 6, the wiper blades are designed as eccentrically mounted angular blades 20. The longer one The wiper leg 21, which brushes along the evaporator wall, serves to spread the liquid on the heated wall and as radiation protection, the shorter leg 22 as a scraper for the condensation layer.

Claims (7)

Patent claims: 1. Thin-film evaporator with a stirrer for spreading the liquid to be treated on a heated wall and with a built-in condenser, whose condensation surfaces at least partially opposite the evaporation surfaces at the same axial height, thereby characterized in that, viewed in the radial direction, the one closest to the evaporation surface (3) Edge of the agitator blades (10, 17 or 21) in a manner known per se compared to the Condenser (12) facing edge runs backwards in the direction of rotation of the agitator and the The blades (10, 17 or 21) of the agitator are arranged so close together that they are louvre-like, but still at a distance from one another, cover them in such a way that any one can see through Point of the cooled condenser surface (12) to the opposite evaporation surface (3) impossible is. 2. Thin film evaporator according to claim 1, characterized in that the agitator blades (17) are rigidly attached to the agitator (8). 3. Thin film evaporator according to claim 1, characterized in that the agitator blades (10) are articulated are attached to the agitator (8). 4. Thin film evaporator according to claim 1, characterized in that the agitator blades (20) as eccentrically mounted angular wings (21,22) are formed. 5. Thin film evaporator according to claim 2, characterized in that the agitator blades (17) on their long sides are incised radially and the tabs (18, 19) between the incisions the wing plane are bent out. 6. Thin film evaporator according to claim 5, characterized in that the tabs (18, 19) are adjacent The agitator blades (17) are offset in the axial direction. 7. Thin film evaporator according to claim 5, characterized in that the tabs (18,19) are adjacent The agitator blades (17) rotate in the opposite direction. 1 sheet of drawings 909 647/371 cl.