GB2095815A

GB2095815A - A treatment vessel having a jacket adapted as a heat exchanger

Info

Publication number: GB2095815A
Application number: GB8207773A
Authority: GB
Original assignee: Mueller & Co Schwelmer Eisen; SCHWELMER EISENWERK MULLER AND CO GmbH
Current assignee: Mueller & Co Schwelmer Eisen; SCHWELMER EISENWERK MULLER AND CO GmbH
Priority date: 1981-03-27
Filing date: 1982-03-17
Publication date: 1982-10-06
Also published as: DE3112154A1; GB2095815B; IT8219800A0; IT1153472B; FR2502765A1

Abstract

A treatment vessel (1) for chemical engineering and like purposes, having a jacket adapted as a heat exchanger, has the jacket formed by a jacket plate (2) and at least one external heat exchange half-tube (3), which is welded in position along a helical line and through which a cooling or heating agent is circulated, and in order to reduce the material consumption for the heat exchange half-tube and the fabrication costs, with particular reference to welding, without influencing the heat exchange efficiency adversely, the half-tube has a semi-elliptical cross-section, the ratio (f/e) between the major and minor axes being in the range 2 to 4, preferably in the range 2.5 to 3.5, and most preferably substantially 3, while the minor axis (e) is disposed orthogonally to the jacket plate (2). <IMAGE>

Description

SPECIFICATION A treatment vessel having a jacket adapted as a heat exchanger This invention relates to a treatment vessel for chemical engineering and like purposes, having a jacket adapted as a heat exchanger, in which the jacket consists of a jacket plate and at least one external heat exchange half-tube welded in position along a helical line. Vessels of this type are used as mixers, receivers, stock tanks and columns in which chemical reactions take place or products are heated or cooled as required. The treatment vessel may be adapted as a pressure vessel or one working without pressue, with or without a coverplate. The jacket may be provided with a single heat exchange half-tube laid along a helical line, or with a plurality thereof laid in the same way as a multiple-start thread.For terminological reasons, the following description will refer exclusively to a single heat exchange half-tube.

In known treatment vessels of this type, the heat exchange half-tube has a semicircular crosssection. It is formed by bending from a plate strip of the required width. The spacing between turns is determined by the heat exchange requirements, so adapted that the operations of welding the heat exchange half-tube on the jacket plate are without practical difficulties. From this requirement, together with other constructionaily and thermodynamically determined parameters, heat exchange in the treatment vessel takes place at a characteristic degree of efficiency.The heat exchange efficiency of this type of treatment vessel is superior to that of the conventional double-jacketed vessel, but the material consumption and fabrication costs are significantly higher than for the conventional double-jacketed vessel, the fabrication costs being determined primarily by the length of the welds deposited to attach the heat exchange halftube to the jacket plate.

The object of the invention is to provide a treatment vessel of the type in question with which the material consumption and fabrication costs can be reduced without influencing the heat exchange efficiency level.

According to the present invention, a treatment vessel for chemical engineering and like purposes has a jacket adapted as a heat exchanger, in which the jacket consists of a jacket plate and at least one external heat exchange half-tube welded in position along a helical line, the heat exchange half-tube having a semi-elliptical crosssection of which the ratio of major to minor axes is in the range 2 to 4 (preferably in the range 2.5 to 3.5) while the minor axis is disposed orthogonally to the jacket plate.

The invention arises from the discovery that significant savings can be made on material consumption and fabrication costs, more specifically the length of welding, in a treatment vessel of the type in question in which the heat exchange half-tube is formed from a plate strip of the required width, when the plate strip of the prescribed width is formed into a semi-elliptical rather than a semicircular cross-section. When the semi-elliptical cross-section has the specified ratio and is disposed with the minor axis orthogonal to the jacket plate, it is possible without adjusting any other constructional and thermodynamic parameter not merely to maintain the original heat exchange efficiency but even to improve it to a surprising extent. The results are particularly favourable when the ratio of major to minor axes is substantially 3.

The invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a fragmentary elevation, partly longitudinally sectioned, of part of a known treatment vessel having a jacket adapted as a heat exchanger; Figure 2 is a similar view to Figure 1 but shows a treatment vessel in accordance with the invention; and Figure 3 shows alternative forms at a, b and c for the semi-elliptical cross-section of the heat exchange half-tube in a treatment vessel in accordance with the invention, corresponding on a larger scale to the portion A of the section in Figure 1.

Each treatment vessel 1 shown in the Figures is intended for chemical engineering and like purposes. It has a jacket 2, 3 adapted as a heat exchanger. The jacket 2, 3 as such consists of a jacket plate 2 and a single external heat exchange half-tube 3 welded in position. This heat exchange half-tube 3 extends along a helical line.

Figure 1 shows the construction of a treatment vessel 1 of this type, of prior art. The crosssection of the heat exchange half-tube 3 is semicircular.

In Figure 2, the cross-section of the heat exchange half-tube 3 is semi-elliptical. The semielliptical cross-section is disposed with its minor axis (e) orthogonal to the jacket plate 2. The ratio (f/e) between the major axis (f) and the minor axis (e) is in the range 2 to 4. In Figure 3a this axial ratio is 2; in Figure 3b it is 3, which is preferred; and in Figure 3c it is 4.

A comparison of Figures 1 and 2 makes it quite clear that when the spacing (m) between turns in the heat exchange half-tube 3 welded helically on the jacket plate 2 is held constant, a significant reduction in the length of the welds is achieved. If the ratio (f/e) between the major and minor axes is about 2 (Figure 3a), the resulting reduction in the length of the welds is about 20%. If the axial ratio (f/e) is 3 (Figure 3b), the resulting reduction in the length of the welds is about 25%. If the axial ratio (f/e) is 4 (Figure 3c), a reduction of about 30% is attained in the length of the welds.

At the same time, a substantial reduction is achieved in material consumption, i.e., a smaller length of plate strip is consumed in forming the half-tube 3. However, the suprising result is also achieved of improving the heat transfer factor, which becomes 11% higher at an axial ratio (f/e) of 3, when the heating or cooling agent is circulated at the same stream velocity as in the corresponding semicircular cross-section. At the same time, the throughput of heating or cooling agent is reduced by 34% at this preferred ratio.

Claims

1. A treatment vessel for chemical engineering and like purposes having a jacket adapted as a heat exchanger, in which the jacket consists of a jacket plate and at least one external heat exchange half-tube welded in position along a helical line, the heat exchange half-tube having a semi-elliptical cross-section of which the ratio (f/e) of major to minor axes is in the range 2 to 4 while the minor axis (e) is disposed orthogonally to the jacket plate.

2. A treatment vessel as in Claim 1 wherein the ratio (f/e) of major to minor axes is in the range 2.5 to 3.5.

3. A treatment vessel as in Claim 1 or Claim 2, wherein the ratio (f/e) of major to minor axes is substantially 3.

4. A treatment vessel substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings and any one of Figures 3a, b or c of the accompanying drawings.