Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor
Reexamination Certificate
2000-07-28
2003-07-29
Warden, Jill (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
C422S130000, C422S091000, C422S240000, C422S241000
Reexamination Certificate
active
06599483
ABSTRACT:
The invention relates to a model reaction pressure vessel made of metal for carrying out chemical reactions at various pressures, having a cup-shaped bottom part and a welded-on lid, and to a reaction arrangement consisting of an autoclave and such a reaction pressure vessel inserted into the autoclave. In particular, the invention relates to such a reaction pressure vessel of the aforesaid type which is provided with various built-in components and lid mountings and permits a pressure correction, the feeding of reagents and a temperature measurement and pressure measurement in the reaction pressure vessel.
Cylindrical metal vessels are normally used as model reaction pressure vessels on a laboratory scale for testing chemical reactions. In most chemical companies, such model reaction pressure vessels are preferably used in a standardized size of about 50 mm diameter and with an equally large height in order to create uniform boundary conditions and thus comparable test conditions.
In this case, the model reaction pressure vessels serve to simulate reactors which are used on a large industrial scale for carrying out chemical reactions. In such reactors for chemical reactions, chemical preparations are made to react with one another, in which case, during the subsequent reaction, pressures which generally can only be affected slightly from outside occur in the interior space of the reactor. In order to be able to reconstruct such chemical reactions on a model scale, model reaction pressure vessels having a relatively thin wall must be used so that the mass of the wall has as little effect as possible on the chemical reactions, in particular also on the temperature of the chemical reactions. When thin walls are used for the model reaction pressure vessel, however, the pressure produced in the reaction pressure vessel, which pressure may partly increase very rapidly during chemical reactions, can generally no longer be absorbed. Therefore such model reaction pressure vessels are inserted into autoclaves, so that the pressure difference between the interior space of the model reaction pressure vessel and the interior space of the autoclave can be kept small by appropriate control of the pressure in the interior space of the autoclave. Thus generally only relatively small pressure differences act on the walls of the model reaction pressure vessel. Since the readjustment of the pressure in the interior space of the autoclave is carried out with a corresponding deviation and time delay, a vacuum relative to the interior space of the autoclave may also occur in the interior space of the model reaction pressure vessel.
At present, model reaction pressure vessels are produced by the cylindrical wall first of all being bent from sheet metal and being butt welded longitudinally. The lid and the base are produced from flat sheet-metal blanks, the margin of which is given a raised flange. They are then inserted into the sheet-metal cylinder and are flange or seam welded.
This production sequence has several disadvantages. At the longitudinal seam and during the flange welding with the arc welding process, scale formation in the vessel interior cannot be avoided. The scale layer has an effect on the chemical reaction of the test medium and leads to non-reproducible results.
A wedge-shaped dead space is produced between the base or the lid and the side wall by the flanging, and this dead space traps, for example, non-reactive gas residues after the vessel has been filled. Furthermore, this dead space may lead to incomplete mixing of a plurality of reaction partners poured in one after the other. This results in an inhomogeneous mixture ratio, which impairs the reaction and thus the test results.
Furthermore, the thermodynamic equilibrium will be affected by the gas trapped in the dead space as non-reactive component.
The dead space and the scale formation are disturbing in particular in the base region, since the vessel is used in the upright position and the reaction components come directly into contact therewith. In the lid region, the disruptive influence is less.
The aforesaid scale layer, which is produced in the vessel interior during the arc welding process, can certainly be avoided to the greatest possible extent by the use of seam resistance welding for joining the lid and base to the cylinder wall. However, on account of the minimum diameter of the rollers of the welding tool, which diameter must not be less than a certain value, pipe connections and the like can only be attached in the lid at a subsequent stage, since these pipe connections and the like otherwise hinder the welding rollers. This means that the pipe connections or the like have to be soldered in place subsequently, with the disadvantage that the ingress of soldering and flux residues into the vessel cannot be avoided. In addition, the soldering material is rigid and does not follow the movements of the more elastic metal under pressure loading. The result of this is that the soldered joint only withstands the pressure loading to a limited extent and in particular that the soldered joint suffers fatigue during operation due to pressure fluctuations.
From the user's point of view, there is a great need to be able to equip the vessels with pipe connections and screw fittings as far as possible individually. This requirement also cannot be fulfilled by the production processes described. The setting-up times are relatively long, so that only the respective production of a very large quantity is viable. The prefabrication of closed universal vessels is also no solution, since the openings for the pipe connections and screw fittings can only be made subsequently by means of piercing the lid and thus not in a true-to-size manner. The problems described with regard to the soldering are further increased and lead to an incalculable risk with regard to the reproducibility of the test results.
On account of the requisite chemical passivity, the vessels are preferably produced from high-grade steel. For reactions with especially aggressive substances, even this material is not sufficiently resistant, especially in the case of reactions which run for several hours. It is therefore desirable to apply coatings in the vessel interior, as also used on a production scale in large reactors (e.g. enameling). This is no longer possible at a subsequent stage in the case of fully welded vessels in the known form. Coating before the welding entails the disadvantage that the coating will be partly destroyed during the subsequent welding or will not withstand the high temperatures, so that decomposition products may pass into the interior space of the vessel.
The object of the invention is to provide a reaction pressure vessel which has the required pressure resistance and in which the abovedescribed problems which occur in the prior art are avoided to the greatest possible extent.
In particular, a reaction pressure vessel which can be used as a reaction vessel and for this purpose can be equipped individually with built-in lid components and lid mountings in an efficient manner even in smaller quantities is to be provided.
Furthermore, a reaction arrangement consisting of an autoclave and a model reaction pressure vessel inserted into the autoclave, in which the problems of the prior art are largely avoided, is to be provided.
This object is achieved by a model reaction pressure vessel as claimed in claim
1
.
On account of the one-piece construction of the bottom part, all the disadvantages which are associated with the welding-in of the base are avoided. These are essentially the scale layers and the dead space between base and vessel wall. In addition, the pressure retaining strength in the case of a one-piece construction is markedly higher. It is thus possible to design a reaction pressure vessel which has a small wall thickness and in which the effect of the wall of the reaction pressure vessel on the chemical reactions can be kept slight.
The lid is welded onto the cup-shaped bottom part. The special lid form according to the
Ihlenfeld Gerd
Seiffert Volkhard
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