SHELL-AND-TUBE APPARATUS WITH BAFFLES

Abstract

Shell-and-tube apparatus comprising a plurality of baffles (5) which are arranged along the tube bundle, perpendicular to an axis of the tube bundle and passed through by the said tubes, wherein each baffle is an essentially flat body having openings (11) through which the tubes pass, and in the region of said openings (11) the baffle comprises tabs (12) which protrude from the surface of said baffle.

Claims

1. Shell-and-tube apparatus comprising a plurality of baffles (5) which are arranged along the tube bundle, perpendicular to an axis (20) of the tube bundle (3) and passed through by said tubes, characterized in that: each baffle is an essentially flat body and comprises a metal plate (10) with openings (11) for the passage of the tubes through said baffle; at said openings (11) the baffle comprises tabs which protrude away from the metal plate, said tabs are configured to operate as elastic supports for the tubes and/or to operate as fluid-dynamic tabs adapted to deviate a fluid traversing the shell side of the apparatus.

2. Apparatus according to claim 1, wherein all tabs of each baffle extend from the same side (13) of the respective baffle.

3. Apparatus according to claim 1 or 2, wherein the shell-side gaseous flow is axial or predominantly axial.

4. Apparatus according to claim 3, wherein at least some of said tabs are fluid-dynamic tabs adapted to deviate the shell-side gaseous flow from the main axial direction.

5. Apparatus according to any of claims 1 to 4 comprising first baffles (5a) having a first configuration of tabs and second baffles (5b) having a second configuration of tabs, wherein the first baffles and the second baffles alternate along at least a part of the tube bundle and wherein said first configuration and second configuration of tabs are conjugate to impart to the shell-side flow a movement component transverse to the axis (20) of the tube bundle (3).

6. Apparatus according to claim 5, wherein: the first baffles (5a) have tabs (112a) configured to direct the shell-side flow in a first direction forming, in a reference plane, a first angle (a1) with the axis of the tubes, the second baffles (5b) have tabs (112b) configured to direct the shell-side flow in a second direction (2a) forming, in said reference plane, a second angle with the axis of the tubes, said second angle having a sign opposite to the first angle, thus obtaining shell-side flow lines which, passing through the baffles, are alternately deviated in different directions.

7. Apparatus according to claim 6, wherein the shell-side flow lines are substantially sinusoidal.

8. Apparatus according to claim 5, wherein the first baffles (5a) and the second baffles (5b) comprise tabs (212a, 212b) directed so as to impart to the shell-side fluid a substantially helical flow about the axis of the tube bundle.

9. Apparatus according to claim 8, wherein the tabs (212a, 212b) protrude from opposite sides (13a, 13b) of the respective first baffles and second baffles (5a, 5b) and the baffle tabs facing each other are angularly offset.

10. Apparatus according to any one of the preceding claims, wherein at least one baffle comprises tabs of varying configuration.

11. Apparatus according to any one of the preceding claims, wherein each baffle occupies all or substantially all of the cross-sectional area of the shell side, or only a portion of said area.

12. Apparatus according to any one of the preceding claims, wherein tabs of adjacent baffles rest on opposite sides on each tube.

13. Apparatus according to any one of the preceding claims, wherein the baffles are formed in such a way that: each opening for one or more tubes comprises at least a first region suitable to receive the tube or tubes with play and a second region suitable to receive the tube or tubes with less play or with substantially zero play; each tube of the bundle is received in a first region of a respective seat when the baffle is in a so-called assembly position and is received in a second region of the seat when the baffle is in an operating position.

14. Apparatus according to claim 13, wherein the tabs are positioned relative to the openings (11) so that the tubes move towards said tabs when the baffles are arranged in the operating position, such that the tabs define elastic supports for the tubes when the baffles are in the operating position.

15. Apparatus according to any one of the preceding claims, wherein the tabs are formed by sheet-metal elements mounted on the metal plate in correspondence of the openings.

16. Apparatus according to any one of claims 1 to 14, wherein the openings are punched or cut in the metal plate, and said tabs are formed by strips of material of the metal plate generated by the cutting or punching of the openings, and suitably bent.

17. Apparatus according to any one of the preceding claims, wherein the baffles comprise an outer reinforcing ring having a thickness greater than the thickness of the metal plate.

Description

DESCRIPTION OF THE FIGURES

[0053] FIG. 1 shows a simplified diagram of a shell-and-tube apparatus comprising a set of anti-vibration baffles.

[0054] FIG. 2 shows a tube passing through a baffle in an embodiment of the invention.

[0055] FIG. 3 shows in schematic form a set of baffles of the apparatus shown in FIG. 1, according to a first example of a variant of the invention.

[0056] FIG. 4 is a schematic cross-section through the baffles and the tubes according to FIG. 3 and shows the shell-side flow lines.

[0057] FIG. 5 shows a detail of FIG. 4.

[0058] FIG. 6 shows a set of baffles in a second variant of the invention.

[0059] FIG. 7 shows a set of baffles in a third variant of the invention.

[0060] FIG. 8 is a schematic cross-section through the baffles and the tubes according to FIG. 7.

[0061] FIG. 9 shows a set of baffles in a fourth variant of the invention.

[0062] FIGS. 10 to 13 show a number of variations of embodiment of the tabs of the baffles.

[0063] FIGS. 14 and 15 show further embodiments of the tabs of the baffles.

DETAILED DESCRIPTION

[0064] FIG. 1 shows in schematic form a shell-and-tube apparatus 1 comprising: a shell 2; a straight-tube bundle 3; a plurality of baffles 5 separated by an interval p; two tube plates 6. In FIG. 1, for simpler illustration, only the axes of the tubes are indicated. Moreover the central axis 20 of the tube bundle 3 which is parallel to the axes of the tubes is indicated.

[0065] Each of the baffles 5 (FIG. 2) comprises essentially a metal disc 10 in which openings 11 for allowing the tubes 4 to pass through are formed. In the region of said openings 11, or at least some of them, the baffle 5 comprises appendix tabs 12 formed by strips of material of the disc 10 which protrude from one side 13 of the disc 10.

[0066] The openings 11 and the tabs 12 may be formed using various methods. For example: the openings 11 are obtained by means of partial punching and the tabs 12 are formed by strips of the material of the disc 10, which instead of being removed, remain attached to the disc; the openings 11 may be obtained using a suitable cutting method, preferably laser or water-jet cutting, and subsequent bending of strips to form the tabs 12; the tabs 12 are thin sheet-metal elements which are mounted on the disc 10. These examples are provided by way of a non-limiting example and other manufacturing methods are possible.

[0067] Each opening 11 is passed through by a tube 4 or several tubes 4 depending on the specific embodiment.

[0068] FIGS. 3 to 5 show an embodiment (shift lock type) in which the tubes 4 can be freely inserted into the openings 11, with a certain amount of play, when the baffles 5 are in an axially offset assembly position. Once insertion of the tubes has been completed, the baffles can be locked on the tubes with conjugate linear displacements +f or f which bring the said baffles into alignment. The direction of said displacements +f, f is also called locking direction. Preferably, adjacent baffles are locked by displacements in opposite directions.

[0069] For this purpose, for example, the openings 11 have an essentially trapezoidal form comprising a base portion suitable to receive a tube with play, and flanks converging towards a tapered head portion for locking the tube. Such an embodiment is also shown in FIGS. 10-15.

[0070] The set of baffles 5 comprises first baffles 5a having a first configuration of tabs 112a and second baffles 6b having a second configuration of tabs 112b in which the first baffles 5a and the second baffles 5b alternate with each other in the longitudinal direction of the tube bundle. The figure also shows a tube plate 6. In the example the baffles 5a and 5b can be locked on the tube bundle by means of the linear displacements +f, f, respectively.

[0071] The tabs 112a with said first configuration protrude from the respective baffles 5a in a direction forming, in a reference plane, a first angle a1 with the direction of the direction of the axis 14 of the tubes and the axis 20 of the tube bundle 3.

[0072] The tabs 112b with said second configuration protrude from the respective baffles 5b in a second direction forming with said direction of the axes 14 and 20, in the same reference plane, a second angle a2 with a sign opposite to that of the first angle a1 (FIG. 5).

[0073] Preferably said second angle is equal and opposite to said first angle, i.e. a2=a1.

[0074] More advantageously, the absolute value (modulus) of said first angle a1 and second angle a2 is comprised between 30 and 60 degrees, and is preferably 45 degrees.

[0075] Said reference plane is for example the plane shown in FIG. 4.

[0076] With reference to FIG. 5 the upper surface 120 of a tab 112a faces the opening 11 and comprises a flat surface inclined at said angle a1 relative to the direction of the axis 20 of the tube bundle. Similarly the upper surface 121 of a tab 112b has a flat surface with an inclination a2 relative to the said axis 20.

[0077] As a result of this arrangement, as shown in particular in FIG. 4, the tabs 112a and 112b deviate the shell-side flow inside the apparatus 1 alternately in two different directions, for example upwards and downwards, resulting in substantially sinusoidal flow lines Fs bending upwards or downwards while traversing the first baffles 5a or the second baffles 5b, respectively.

[0078] In FIGS. 3 to 5 the tabs 112a, 112b are arranged on one side of the opening 11 which moves towards the tube 4 as a result of the locking displacement +f or f, for example on the smaller side of trapezoidal openings 11. In this way the aforementioned tabs 112a, 112b provide an elastic support for the tubes 4 when the baffles 5a, 5b switch from the assembly position to the locked position.

[0079] In FIG. 5 in particular it can be seen that a tube 4 makes a bearing contact alternately according to one direction and according to an opposite direction, for example upwards and downwards. In the locking phase, the tubes 4 are wedged between the inclined flanks of the openings 11; the tabs 112a, 112b provide an elastic element to recover any play due to the constructional tolerances.

[0080] It can be understood that the tabs 112a, 112b have both a fluid dynamic function, determining sinusoidal flow lines, and a structural function of elastically supporting the tubes 4, compensating for play due to the constructional tolerances, and preventing vibrations.

[0081] FIG. 6 shows a variant of the embodiment of FIGS. 3-5, in which the tabs 112a, 112b are arranged laterally with respect to the locking direction of baffles 5, for example along the converging flanks of the trapezoidal openings 11.

[0082] FIGS. 7 and 8 shows a variant of the twist-lock type in which the baffles 5 pass from an assembly position (where the tubes can be freely inserted with play into the openings 11) into a locking position with conjugate rotations + or about the axis 20. Preferably adjacent baffles allow locking of the tubes with rotations in opposite directions.

[0083] In said twist-lock embodiment, the set of baffles 5 advantageously comprises first baffles 5a and second baffles 5b with tabs 212a, 212b configured to impart a helical motion to the shell-side fluid.

[0084] In greater detail, according to the shown embodiment, the tabs 212a, 212b extend from opposite sides of the baffles, for example the tabs 212a extend from front sides 13a of the baffles 5a and the tabs 212b extend from rear sides 13b of the baffles 5b. The tabs 212a, 212b are also angularly offset. As a result of this arrangement, as shown in FIGS. 7 and 8, the tabs 212a, 212b deviate the shell-side flow helically around the direction of the axes 14 and 20, thus generating essentially helical flow lines Fe.

[0085] In FIGS. 7 and 8, the tabs 212a, 212b are positioned, relative to the openings 11, so that the tubes 4 move towards said tabs 212a, 212b when the baffle passes from the assembly position into the operating position. In this way, the tabs also act as elastic supports for the tubes and for recovery of the play (in a similar manner to that shown in FIGS. 3-5).

[0086] FIG. 9 shows a variant of FIGS. 7 and 8 in which the tabs 212a, 212b are positioned laterally with respect to the locking movement (in a similar manner to that shown in FIG. 6). With the configuration of the tabs shown in FIG. 9 a sinusoidal flow associated with the twist-lock configuration is obtained.

[0087] FIGS. 10-13 show examples of embodiment of the tabs, indicated generally by the reference number 12. FIGS. 14 and 15 shows further examples of embodiment. Said examples of embodiments in FIGS. 10 to 15 are likewise applicable to the various embodiments shown in FIGS. 1-9.

[0088] FIG. 10 shows an example of embodiment in which the tabs 12 have an essentially polygonal trapezium-like form and are connected to the sheet-metal disc along one side 15.

[0089] FIG. 11 shows a variant in which only a part of the material removed from the disc 10 forms the tab 12 and, consequently, the area of the tabs 12 is smaller than the area of the openings 11.

[0090] FIG. 12 shows a variant in which the tabs 12 are joined to a base 16 of the opening 11 having an essentially trapezoidal form.

[0091] FIG. 13 shows a variant in which the openings 11 each comprise two tabs 12 which extend on opposite sides relative to the plane of the baffle.

[0092] Openings with an essentially trapezoidal form as shown in FIGS. 10-12 are generally suitable for receiving only one tube 4; consequently the baffle requires a number of openings 11 equal to the number of tubes 4. FIG. 13 shows an example of an embodiment of opening 11 of the shift-lock type suitable for receiving four tubes.

[0093] FIGS. 14 and 15 show an embodiment in which the tabs 12 are formed by thin sheet-metal elements which are mounted on the disc 10 for example by means of spot welds 25.

[0094] It should be noted that the constructional form shown in FIGS. 14 and 15 may be applied to all the variants of the invention.

[0095] It should be finally noted that embodiments of the invention, for example similar to embodiments of FIGS. 1-9 are also possible without the above described shift-lock or twist-lock baffle locking system.