US3423782A

US3423782A - Rotor for thin layer evaporator

Info

Publication number: US3423782A
Application number: US624892A
Authority: US
Inventors: Gerhard Klosel
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1967-03-21
Filing date: 1967-03-21
Publication date: 1969-01-28
Anticipated expiration: 1986-01-28
Also published as: CH453297A

Description

Jan. 28, 1969 GKLOSEL 3,423,782

ROTOR FOR THIN LAYER EVAPGRATOR Filed March 21, 1967 INVENTOR. GERHARD KLOSEL BY Z WM 1 Jif /HIE):

United States Patent 2 Claims ABSTRACT OF THE DISCLOSURE coid.

The invention relates to rotors for thin layer evaporators, which have many varied uses.

The use of versatile apparatuses for thin layer evaporation, whose action is based on the employment in the evaporation chamber of rotating bodies of different construction which apply a thin layer (film) of the liquid or solution to be evaporated on to the surface which is to be vapour treated is already known. It is also known that the use of a mechanical thin layer evaporator is a function of the film applicator system and is based substantially on the mode of operation of two known systems, in which:

(a) the rotors have rigid or mobile surfaces arranged parallel to the axis, and application of the film is effected by the centrifugal effect produced and by action of the wiper, and

(b) the rotors have axial thrust and serve as wipers,

in a screw or spiral system.

Furthermore the rotor systems mentioned above may be distinguished from each other by their fundamentally difierent speeds of rotation, which again are characteristic of their possible uses, in that:

(a) the rotors have high speeds of rotation (surface rotors) and may be used for low consistency, nonadhering liquids or solutions; and

(b) the rotors have low speeds of rotation (screws or spiral rotors) and may be used for high consistency, bonding liquids or solutions.

In view of the large variety of systems of materials which one wishes to work up in thin layer evaporators of this type the evaporation of liquids or solutions which are sticky and tend to form incrustations can be particularly difficult in the known apparatuses, in which this problem can only be overcome satisfactorily by use of rotors that have an axial thrust and serve as wipers. However, this arrangement is not particularly suitable for liquid solutions which are difiicult to separate (solutions of similar density, narrow boiling range) since the separating effect produced by the centrifugal force of the rotating surfaces is absent.

The object of the invention is to overcome these disadvantages which in particular may lead to:

(a) a narrow, and in many cases very limited, utility for different liquids or solutions,

3,423,782 Patented Jan. 28, 1969 (b) the absence of a continuous transition of high speed (750 to 1,500 revs/min.) to low speed (50 to 750 revs/min.) film applicators,

(c) the liability of the liquids or solutions concentrated by evaporation to form accretions on the vapour treated surface and (d) contamination of the product by metal filings, due

to the grinding effect of some film applicators.

These disadvantages may be overcome according to the present invention by providing a helix mounted on a shaft by means of radial supports arms, in the turns of which helix are situated blades which are arranged axially along the shaft and offset by 180 between the individual turns of the helix.

Preferred embodiments of the invention will now be illustrated with reference to the accompanying drawings in which:

FIG. 1 is an elevational view of a rotor,

FIG. 2 is a cross-section and FIG. 3 shows such a rotor installed in a thin layer evaporator.

The rotor comprises a flat strip 2 wound round a shaft 1 a tan angle of about 45 thereto in the form of a helix which is fixed to the shaft 1 by means of distance pieces 3. Rectangular blade stumps 4 are arranged on the shaft at intervals of 180 between the turns of the spiral. The blade stumps 4 are staggered in relation to each other in such a manner that the areas swept out by the blades on the evaporator cylinder 5 enclosing them overlap each other.

It has now been found that liquids and solutions which tend to adhere and stick, and also liquid solutions of low viscosity can easily be treated by the arrangement of a helix and blade stumps according to the present invention, which is not the case when using the helix arrangement system alone.

I claim:

1. A rotor for thin layer evaporators, comprising a shaft with a helix attached thereto, said helix being attached to said shaft by means of radial support arms between the turns of which helix are arranged rigid blades which are all coplanar with the shaft axis and with each other and are arranged axially along said shaft and staggered in relation to each other by 180 and is situated between the turns of the helix, said blades having a radial extent at least as great as the inner diameter of the helix.

2. A rotor for thin layer evaporators as claimed in claim 1, comprising said blades overlapping each other in the axial direction.

References Cited UNITED STATES PATENTS NORMAN YUDKOFF, Primary Examiner.

J. SOFER, Assistant Examiner.

US. Cl. X.R.

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