Reduced vibration tube bundle device having slotted baffles
a technology of tube bundles and baffles, which is applied in the direction of safety devices for heat exchange apparatus, water supply installation, lighting and heating apparatus, etc., can solve the problems of increasing the likelihood of vibration, damage to the bundle, and the potential for flow-induced vibration damage of the tube bundle, so as to reduce vibration and improve heat transfer , the effect of improving the effect of heat transfer
Inactive Publication Date: 2008-10-09
EXXON RES & ENG CO
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Benefits of technology
[0011]In accordance with an aspect of the present invention, the tube bundle device includes at least one slotted support baffle. The slotted support baffles provide support for the individual tubes within the tube bundle. Each support baffle includes a plurality of spaced apart slots formed therein. Each of the slots being sized to receive at least one of the tubes of the tube bundle therethrough. The cross section of each slot is slightly larger than the outer diameter of the tubes for easy insertion of the tubes within the tube bundle device. Each slotted support baffle has an outer perimeter and a blocking area formed between the outer perimeter and the plurality of spaced apart slots. The blocking area prohibits the flow of fluid therethrough. As result, fluid flowing through the tube bundle device is directed inwardly towards the tube bundle when the fluid contacts the blocking area. The blocking area is sized to be located within a gap between the housing and outer tubes of the tube bundle device. Each slotted support baffle may also include at least one partition lane blocking area formed therein. The partition lane blocking area(s) being sized to be received within the partition lane or lanes of the tube bundle. The partition lane blocking areas prevent the flow of fluid through the partition lanes. As a result, fluid flowing through the partition lane is directed towards the tubes of the tube bundle when the fluid contacts the partition lane blocking area. It is contemplated that in the case of a single-pass tube bundle device, the partition lane will be omitted. Each slotted support baffle may contain a multitude of blocking areas which correspond to the partition lanes in the tube bundle.
[0014]In accordance with another aspect of the present invention, the tube bundle device includes at least one blocking baffle. Unlike the support baffle, the blocking baffle does not support the tubes. Instead, the blocking baffle functions to control the flow of fluid within the tube bundle device. Each blocking baffle includes a blocking plate having an outer perimeter and at least one plate opening sized to receive the tubes of the tube bundle device therethrough. A blocking plate blocking area is formed between the outer perimeter of the blocking plate and the at least one plate opening. The blocking plate blocking area prevents the flow of fluid therethrough. As a result, fluid flowing through the tube bundle device is directed inwardly towards the tube bundle when the fluid contacts the blocking plate blocking area. The blocking plate blocking area is sized to be located within a gap between the housing and outer tubes of the tube bundle. The blocking plate baffle may further include at least one partition lane blocking plate blocking area formed therein. The number of partition lane blocking plate blocking areas is dependent upon the number of partition lanes within the tube bundle. As discussed above, the tube bundle may not include a partition lane (e.g., a single-pass heat exchanger typically does not include partition lanes). As such, the partition lane blocking plate blocking area may be omitted. Each partition lane blocking plate blocking area is sized to be received within a corresponding partition lane of the tube bundle device. The partition lane blocking plate blocking area may extend, for example, from opposing sides of the blocking plate blocking area between two openings in the plate when the blocking plate baffle is used in a U-bend tube bundle device having two passes therethrough. The partition lane plate blocking area prevents the flow of fluid therethrough. As a result, fluid flowing through the partition lane is directed towards the tubes of the tube bundle when the fluid contacts the partition lane blocking plate blocking area.
[0016]In accordance with another aspect of the present invention, at least one elongated tube support member is provided to support the tubes of the tube bundle to reduce vibration. Each elongated tube support member is selectively located in the space formed between adjacent rows of tubes. The elongated tube supports may be inserted between the tubes between the blocking and slotted support baffles.
[0017]It is another aspect of the present invention to provide a method of controlling the flow of fluid within a tube bundle device. The method includes redirecting at least a portion of the flow of fluid in the gap to the tube bundle. The method further includes redirecting at least a portion of the flow of fluid in the partition lane to the tube bundle. The redirecting of the fluid flow is accomplished by locating the baffles at selected locations along the tube bundle. The blocking areas and blocking plate blocking areas on the slotted support baffles and the blocking baffles redirect the flow of fluid away from the gap between the housing or shell and the tube bundle into the tube bundle to improve heat transfer. The partition lane blocking areas redirect the flow of fluid away from the partition lane to improve heat transfer.
Problems solved by technology
A common limiting factor experienced when evaluating the increase of rates in a heat exchanger is the potential for flow-induced vibration damage of the tubes.
Fluid flow patterns around the tubes may give rise to flow-induced vibrations of an organized or random oscillatory nature in the tube bundle and in the case of devices such as heat exchangers in which heat transfer takes place between the tubes and the surrounding fluid, the changes in the velocity, temperature and density of the fluid as it circulates and flows around the tubes may increase the likelihood of vibration.
If these vibrations reach certain critical amplitudes, damage to the bundle may result.
Tube vibration problems may be exacerbated if the heat exchanger equipment is retubed with tubes of a different material to the original tubes, for example, if relatively stiff materials are replaced with lighter weight tubes.
Flow-induced vibration may also occur when equipment is put to more severe operating demands, for example, when other existing equipment is upgraded and a previously satisfactory heat exchanger, under new conditions, becomes subject to flow-induced vibrations.
Rod baffle exchangers, however, tend to be approximately 30 to 40% more expensive than conventional shell-and-tube exchangers and there have been situations where tube bundle devices of this kind have failed owing to flow-induced vibrations.
If the rods are slightly oversized, tube loading will be very difficult and expensive.
Increasing baffle spacing is usually not an attractive option, since increased baffle spacing increases the likelihood of flow-induced tube vibration occurrence.
This, however, is even more expensive than the rod baffle design.
Like the rod baffle, the eggcrate is also susceptible to tube chatter that could lead to tube failure.
Method used
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[0026]The present invention will now be described in greater detail in connection with the figures. FIG. 1 is a schematic view of a tube bundle 10 in accordance with an aspect of the present invention. The tube bundle 10 is part of a tube bundle device 1 (e.g., a heat exchanger or other suitable heat transfer component). The tube bundle 10 includes a plurality of parallel tubes 11. It is contemplated that the present invention is not limited to tubes; rather, it is contemplated that the rods and other heat transfer or fluid flow elements may be employed and are considered to be well within the scope of the present invention. As shown in FIG. 1, the parallel tubes 11 extend between a pair of tubes sheets 13 and 14. The tubesheet 13 may be a fixed tubesheet that is welded to the housing or shell 20. The tubesheet 13 may also be a stationary tubesheet that is secured, but not welded to the housing 20. The tubesheet 14 illustrated in FIG. 1 is a floating tubesheet. The tubes 11 may be a...
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A slotted support baffle and a blocking baffle are disclosed for a tube bundle device. The baffles include blocking areas, which redirect the flow of fluid within the tube bundle device to improve heat transfer. The slotted support baffle includes a slot and rib structure which supports the tubes of the tube bundle. The support baffles may be used in combination with elongated tube supports.
Description
CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application relates and claims priority to US Provisional Patent Application No. 60 / 849,768, entitled “Reduced Vibration Tube Bundle Device Having Flow Directing Baffles”, filed on Oct. 6, 2006.FIELD OF THE INVENTION[0002]This invention relates to tube bundle devices such as heat exchangers, condensers and similar fluid-handling equipment with collections of tubes or rod-like elements, for example, in devices such as nuclear reactors, electrical heaters, or any collection of parallel cylindrical shapes that has a fluid flow passing over the tubes or other elements. In particular, the present invention relates to a baffle structure for use in connection with the bundle to provide support to the individual tubes within the bundle and to direct the flow of fluids within the heat exchanger shell towards the heat transfer tubes of the bundle.BACKGROUND OF THE INVENTION[0003]Tube bundle equipment such as shell and tube heat exchangers and ...
Claims
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Login to View More IPC IPC(8): F28F9/00
CPCF28D7/06F28D7/1607F28F9/0131F28F2265/30Y10T137/0318F28D7/16F28F9/013
InventorWANNI, AMAR S.RUDY, THOMAS M.
OwnerEXXON RES & ENG CO