GB1603361A - Jacketed vessel - Google Patents

Description

(54) A JACKETED VESSEL (71) We, G. U. ENGINEERING LnUITED, a British company of Coppermill Court, West Hyde, Rickmansworth, Hertfordshire, WD3 2XS (formerly of Maple Cross, Denham Way, Rickmansworth, Hertfordshire WD3 2RS), do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement :- This invention relates to vessels provided with temperature regulating jackets which may be supplied with fluid. at desired temperatures to heat, cool or maintain at a desired temperature the contents of the vessel.

In our co-pending Application No.

24996/76 (1, 582, 836) there is described and claimed a vessel having a jacket adjoining a wall thereof, a chamber for a temperature controlling fluid being defined between the jacket and the wall of the vessel, an inlet and an outlet to said chamber being provided in the jacket and a flow guiding member being disposed within said chamber between the jacket and the wall of the vessel for guiding the flow of fluid in the course of its passage through the chamber from the inlet to the outlet, the vessel wall being of sheet metal in the form of a metal sheet spaced from the vessel wall over the major part of the area of the jacket, the jacket having, distributed thereover at intervals, a plurality of localised indentations at which the jacket engages the wall of the vessel, each said indentation being entirely encircled by a respective zone over which the jacket is out of contact with, and spaced from the wall of the vessel.

In a vessel provided with a temperature regulating jacket which has an inlet and an outlet in the form of tubular spigots extending radially from the jacket and via which steam can be supplied to the jacket to heat the contents of the same, the impingement of the steam on the wall of the vessel may, unless appropriate preventive measures are taken, give rise to thermal shock and localised thermal stresses which may lead to an accelerated failure rate.

One measure which may be taken to prevent such thermal shock and the like is the provision of a deflector or baffle plate secured to the vessel wall immediately opposite the inlet so that steam entering via said inlet impinges directly on said baffle plate.

However, where the spacing between the vessel wall and the jacket is small, the provision of such a baffle plate may unduly restrict the flow cross-section in the region between the inlet and the remainder of the interior of the jacket. This problem can be particularly acute in the case of vessels which are multi-purpose in the sense that they may be intended to be heated or cooled and using any medium the user cares to select, since the restriction in the flow cross section referred to, caused by the baffle plate required to render the vessel suitable for heating by steam may present difficulties when a liquid heating or cooling medium is used.

It is an object of the present invention to provide an improved construction of jacketed vessel whereby the above noted difficulty, among others, may be relieved.

According to one aspect of the invention there is provided a vessel having a jacket extending over a wall thereof, generally parallel with said vessel wall, a chamber for a temperature controlling fluid being defined between the jacket and the wall of the vessel, and an inlet and an outlet to said chamber being provided in the jacket, said inlet having an axis inclined with respect to the normal to the vessel wall at the position of the inlet, and in which the inlet includes a tubular part, the axis of which corresponds to the axis of the inlet, said tubular part being connected with the wall of the jacket via an intermediate part which flares, to increase in flowc ross-section from the tubular part to the jacket wall.

Preferably the vessel wall and the jacket are curved and the inlet extends in a direction substantially tangential to the vessel wall.

Preferably both the inlet and the outlet have their axes inclined with respect to the respective normals to the vessel walls at their respective positions.

In the case where the vessel is intended to be suitable for heating by steam, a baffle plate is preferably secured to the vessel wall at a position, with respect to the inlet, such as to receive the main stream of steam issuing from the inlet during use. However in a case where the vessel is intended to be cooled or heated by a liquid in conditions in which no significant thermal shock arises, the baffle plate may, of course, be omitted.

One advantage of the arrangement according to the invention is that the area of impinge- ment on the vessel wall, or on the baffle plate, of the stream of steam issuing from the inlet, and which is already increased by virtue of the inclination of the socket, is increased still further by divergence of the stream of steam thus reducing thermal shock still further. Anotller adxanta, e, also due in part to the inclination cf the inlet and in part to said flaring of the intermediate part is that due to the increased perimeter of the junction ot the inlet with the jacket wall proper, as compared with the case of a radial inlet, the cross section for flow into the jacket, (or from the jacket, bearing in mind that the connection which is used as the inlet when the jacket is heated by steam may be used as the outlet where the vessel is cooled by a liquid), is not seriously reduced by the presence of the baffle plate in the region of the inlet.

Embodiments of the invention are described below with reference to the accompanying drawings in which: Figure I is a schematic perspective view of a jacketed vessel embodying the invention; Figure 2 is a side elevation view of part of the vessel of Figure I, Figure 3 is a view in section along the line A-A in Figure 2, and Figure 4 is a view in vertical section of part of the side of the vessel of Figures I to 3.

The vessel 10 shown in Figure 1 has the general construction described and claimed in our co-pending Application No. 24996/76, (1,582,836) the vessel being in the form of a tub of sheet metal, for example stainless steel, with a cylindrical side wall 12 which, over the major portion of its height, is surrounded by a sheet metal jacket 20 comprising a wall the major portion of which lies in a cylindrical surface coaxial with the wall 12 and spaced radially outwardly therefrom. At its upper and lower edges the wall of the jacket extends radially inwardly to engage the wall 12 and is welded thereto or is otherwise sealingly connected with the wall 12.

The jacket is indented at intervals to engage the wall 12 of the vessel and is welded to the wall of the vessel in the region of these indentations, the indentations or dimples being indicated at 22.

Disposed within the chamber defined between the wall 12 and the jacket 20 is a flow guiding member, indicated by the broken line 24 in the form of a m-tal strip, bar tube or the like extending around the wall 12 after the fashion of a coil from the upper edge of the jacket to the lower edge thereof.

The flow guiding member 24 thus defines within the jacket, together with the wall 12 and the jacket an extended passage of rectangular section which extends in the fashion of a coil from the top of the jacket to the bottom.

At the top of the jacket is provided an inlet 30 which communicates with the coil like passage within the jacket adjacent the end of the uppermost turn and a similar outlet 32 extends from the jacket at the bottom thereof and communicates with the coil like passage adjacent the end of the lowermost turn.

However, the vessel shown in the accompanying drawings differs from that described in our co-pending Application No. 24996/76 (1,582,836) in the construction in the region of the inlet 30 and outlet 32. Thus, instead of the inlet and outlet having their respective axes extending generally radially with respect to the vessel, the inlet 30 and outlet 32 have their axes inclined so as to be tangential or nearly tangential to the wall 12 and thus so as to be completely or partially aligned with the adjoining portion of the coil like passage.

Referring to Figures 2 and 3, the inlet 30 comprises a cylindrical tubular part 34, the axis 36 of which, constituting the longitudinal axis of the inlet, is inclined with respect to the normal 38 to the wall 12 in the region of the inlet. For ease of illustration, and because, in practice, the diameter of the vessel may be extremely large in relation to the dimensions of the inlet, the walls 12 and 20 are not shown curved in Figure I.

Where the curvature of the vessel wall makes it practicable, the axis 36 of the tubular part 34 may be substantially tangential to the wall 12, but where the vessel is of large diameter in relation to the dimensions of the inlet, a precisely tangential arrangement may not be practicable, and in such cases the axis 36 extends along an imaginary chord intersecting the wall of vessel 10.

Extending between the tubular part 34 and the wall 20 of the jacket is an intermediate part 40 which has the general form of a funnel, flattened slightly on opposite sides and flaring from the tubular part 34 to the wall 20, the height of the intermediate part, as measured from top to bottom in Figure 2, corresponding to the diameter of the tubular part 34. The intermediate part 40 is preferably formed of sheet metal cut and bent to shape and welded up, being also welded to the wall 20 and the respective end of the tubular part 34. The surface of the intermediate part 40 which faces in the outward direction away from the vessel is formed, as shown in Figure 3, as an extension, in the axial direction, of the adjoining surface of the tubular part 34.

The intermediate part 40 is welded to the wall 20 along a weld seam 42 which extends around an elongate aperture 44 cut in the wall 20 and lying within the inner end of the intermediate part 40. Welded to the wall 12 at a position immediatcly opposite the aperture 44 is a metal baffle plate 46 which, in the example shown, is of rectangular form corresponding generally to the form of the aperture 44.

It will be appreciated that since the crosssection available for fluid flow into the jacket in the region of the aperture 44 increases as the length of the perimeter of the aperture 44 as well as being dependent upon the spacing of the wall 20 from the wall 12 in the baffle plate 46, because the perimeter of the aperture 44 is large, this flow cross section is large in relation to the internal cross section of the tubular part 34, even if the spacing of the major part of the wall 20 from the wall 12 is not particularly great.

The tubular part 34 may be internally or externally threaded so that an appropriate screw threaded connection with a supply pipe for steam or some other fluid medium can readily be made, or alternatively, a fixing flange 48, extending radially from the tubular part 34 may be provided at the outer end of the part 34.

It will be appreciated that the construction of the outlet 32 corresponds to that of the inlet 30.

Because the construction described with reference to the drawings avoids flow restrictions in the region of the inlet and outlet, and because the inlet and outlet are aligned with the respective end of the coil-like flow passage by virtue of the inclination of the inlet and outlet, fluid can be passed readily through the jacket via the inlet and the outlet, whether the fluid be gaseous, a vapour such as steam, or a liquid, despite the provision of the baffle plate 46, the function of which is to prevent or alleviate thermal shock and localised thermal stresses in the wall 12 in the region of the inlet due to steam entering the inlet 30 via the tubular part 34, when the vessel is used as a steam heated vessel. The effects of flow restrictions at the inlet and outlet would be most pronounced when a liquid medium was used for heating or cooling the vessel, and in such an application the baffle plate 46 would not normally be required. However, by the construction described, it is possible to provide a vessel which is not limited to one specific mode of use.

Indented jacketed processing equipment such as the vessel described with reference to the drawings can give instant accurate temperature control due to the relatively small volume of steam present at any one time in the chamber defined within the jacket, since it has been found that the spacing between the indented panel or jacket and the wall to which it is applied need often be no greater than"whereas in conventional arrangements using plain jackets it has been customary to provide large steam voids, usually not less than 1"and in some cases up to 2"wide. However, with arrangements having such large steam voids, when, for example a vessel is to be kept at a required temperature by the supply of steam to these voids, there is, during heating up, a lag between termination of the supply of steam and termination of the increase in temperature, so that the vessel and its contents may overshoot the desired temperature by several degrees due to the residual latent heat of the steam in the large voids. This problem can be much reduced by the use of indented jackets of the kind hereinbefore described.

Claims (7)

1. WHAT WE CLAIM IS :- 1. A vessel having a jacket extending over a wall thereof, generally parallel with said vessel wall, a chamber for a temperature controlling fluid being defined between the jacket and the wall of the vessel, and an inlet and an outlet to said chamber being provided in the jacket, said inlet having an axis inclined with respect to the normal to the vessel wall at the position of the inlet, and in which the inlet includes a tubular part, the axis of which corresponds to the axis of the inlet, said tubular part being connected with the wall of the jacket via an intermediate part which flares, to increase in flow cross-section from the tubular part ot the jacket wall.
2. 2. A vessel according to claim I wherein the vessel wall and the jacket are curved and the inlet extends in a direction substantially tangential to the vessel wall.
3. 3. A vessel according to claim I or claim 2 wherein both the inlet and the outlet have their axes inclined with respect to the respective normals to the vessel walls at their respective positions.
4. 4. A vessel according to any of claims 1 to 3 in which a baffle plate is secured to the vessel wall at a position, with respect to the inlet, such as to receive the main stream of steam issuing from the inlet during use.
5. 5. A vessel according to claim I wherein a flow guiding member is disposed within the chamber defined between the jacket and the wall of the vessel, for guiding the flow of fluid in the course of its passage through said chamber from the inlet to the outlet, the vessel wall being of sheet metal and the jacket being in the form of a metal sheet spaced from the vessel wall over the major part of the area of the jacket, the jacket having distributed thereover at intervals a plurality of localised indentations at which the jacket engages the wall of the vessel, each said indentation being entirely encircled by a respective zone over which the jacket is out of contact with and spaced from the wall of the vessel.
6. 6. A vessel according to any of claims 1 to 5 wherein the spacing between the walls between which the chamber for fluid is defined is less than half an inch.
7. 7. A vessel substantially as hereinbefore described with reference to and as shown in the accompanying drawings.