Concentrating evaporators – Film type – Centrifugal
Patent
1993-01-04
1995-05-30
Bascomb, Jr., Wilbur
Concentrating evaporators
Film type
Centrifugal
159 132, 159 49, 159DIG15, 165905, 202236, 2022671, 203 86, B01D 122
Patent
active
054198100
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a thin-film evaporator including a heatable tubular evaporator body with an externally driven rotor equipped with essentially radially oriented vanes being disposed in the product charged interior of the evaporator body.
2. Description of the Related Art
Thin-film evaporator of the above-mentioned type are employed for the concentration of viscous, temperature sensitive and/or coating forming substances. They are all based on the principle of producing, with the aid of a rotating rotor, a thin layer of the product in the interior of a heated cylinder or cone so that the heat introduced through the cylinder wall leads to the evaporation of the liquid. The vapors need traverse only a short path through the product. Thus it is possible to concentrate solids containing liquids to high solids concentrations up to 80 weight % dry substance. The rotor is equipped with rigid vanes which are arranged with a narrow gap of a few millimeters from the heated wall or the rotor is equipped with movable wiper blades so that the product running over the heated walls of the evaporator body can be restricted to a thin film of product. When treating corrosive media, for example for the concentration of acids charged with solids, the corrosion problems cannot be solved with metal materials, particularly since the evaporator body must also be designed as a pressure vessel. Tests with enamel coatings are able to solve the corrosion problem only in special cases, particularly since it is practically impossible in larger units to perform the necessary mechanical work.
SUMMARY OF THE INVENTION
It is the object of the invention to configure a thin-film evaporator of the above-mentioned type so that the evaporator body has good corrosion resistance with good heat conductivity.
This is accomplished according to the invention in that the evaporator body is formed by at least one thick-walled tube of graphite; a plurality of essentially axially extending bores are disposed in the tube wall; and the bore openings at the tube ends each open into an annular channel which is in communication with a connecting pipe stub for a heating medium. Surprisingly, it has been found that such an evaporator body made of a thick-walled graphite tube not only has excellent heat conducting properties but also permits the heating medium to flow through it at high pressures. The interior of such a cylindrical or conical graphite tube can be worked properly and very precisely so that it is possible with the aid of the rotor to apply a uniformly thin product film onto the interior wall of the tube as it is required for high evaporator output.
As an advantageous feature of the invention it is provided that the annular channel is configured as an open groove in a clamping ring that can be placed against the end face of the tube; the tube is held in a sealed manner by way of spring-tensioned clamping anchors between two clamping rings at its ends and the clamping rings are each provided with a connecting pipe stub for the heating medium, with the pipe stub opening into the associated groove. The clamping rings are here made of metal, preferably steel, with their interior faces that come in contact with the product being coated or lined with corrosion resistant materials. Thus, corrosion resistance can also be realized in these regions and advantage is taken of the fact that requirements for precision are less in the regions of the clamping rings that lie outside of the operating range of the rotor vanes. Due to the use of the clamping anchors, the graphite evaporator body is able to retain its simple geometric shape, with the clamping anchors including the required clamping springs being configured in such a way that they are able to withstand the pressures exerted by the heating medium, that is, they keep the clamping rings in close contact with the end faces of the graphite tube.
As a further feature of the invention it is provided that the upper clamping ring, as the head ring,
REFERENCES:
patent: 2721730 (1955-10-01), Clause et al.
patent: 2751339 (1956-06-01), Inman
patent: 2890155 (1959-06-01), Bueche
patent: 2993842 (1961-07-01), Smith
patent: 3054444 (1962-09-01), Robbins
patent: 3054729 (1962-09-01), Smith
patent: 4208243 (1980-06-01), Knotik et al.
patent: 4474233 (1984-10-01), Swozil
Van Der Piepen Rolf
Weimann Lothar
Bascomb, Jr. Wilbur
Buss AG
LandOfFree
Thin-film evaporator made of a corrosion resistant material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thin-film evaporator made of a corrosion resistant material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thin-film evaporator made of a corrosion resistant material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-359308