Heat exchange – Flow passages for two confined fluids – Interdigitated plural first and plural second fluid passages
Reexamination Certificate
2000-02-11
2001-07-31
Lazarus, Ira S. (Department: 3743)
Heat exchange
Flow passages for two confined fluids
Interdigitated plural first and plural second fluid passages
C165S170000, C165SDIG003, C165S167000
Reexamination Certificate
active
06267176
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to heat exchanger assemblies of the type used in an aircraft environmental control system (“ECS”). Such heat exchangers are usually of the fluid-to-fluid type, either gas or liquid, and typically have a core assembly including alternating rows of heat transfer fins and plates. The rows are interposed to create multiple, hot and cold side passageways extending through the core assembly. The passageways may create a counter-flow, parallel flow or cross-flow heat exchange relationship between fluids flowing through the passageways. During operation, heat is exchanged between the fluids flowing through the core assembly.
Because an aircraft ECS often operates at, and generates within itself, extreme temperature and pressure conditions, the heat exchanger is subjected to the adverse effects of temperatures as well as the forces generated by operation of the aircraft. The heat exchanger is manufactured to function in such a hostile environment. Fin-plate type heat exchangers typically include a core and inlet and outlet manifolds. The core typically includes rows of fin assemblies and support plates that support as well as separate adjacent rows of fin assemblies. Each fin assembly is usually formed from one or more corrugated sheets and at least two fluid enclosure bars, which are bonded, typically by brazing, to a pair of support plates. After the components are assembled to form the core, the core is welded to the inlet and outlet manifolds. In order to build up a surface of solid material upon which to weld the manifolds, a butterpass weldment is first placed on the edges of the core.
When heat exchanger cores are subjected to the butterpass and/or general manifold weldment procedures, they may suffer certain drawbacks that increase the manufacturing costs and reduce the overall quality of the resulting heat exchanger. If the core is welded to the manifold, the size (i.e., gage) of the core material receiving the weld may be thicker than would otherwise be needed in order to support the weldment. This additional amount of core material can significantly increase the overall weight of the core assembly. Consequently, the weight of the aircraft is increased which, in turn, increases fuel consumption and increases aircraft operating costs.
If a conventional butterpass or similar weld is used to secure the heat exchanger components, and if there are initial stresses or flaws in the welds, some of the welds may fail. Consequently, the life cycle of the heat exchanger will be reduced.
There currently exists a need for a heat exchanger assembly that overcomes the drawbacks associated with welding the manifolds to the core.
SUMMARY OF THE INVENTION
This need is met by a heat exchanger assembly in accordance with the present invention. The heat exchanger assembly includes a core comprising a plurality of separate fin assemblies, wherein each adjacent pair of fins is separated from one another by a separate support plate. The fin assemblies form at least two fluid passageways extending through the core assembly, allowing heat to be transferred from a first fluid flowing through one passageway to a second fluid flowing through the second passageway. The support plates are positioned on either side of each fin assembly for supporting the fin assemblies in their proper positions while preventing fluid from leaking between flow passageways formed by adjacent fin assemblies. Enclosure bars preferably having pre-formed apertures are positioned at the ends of the fin assemblies and interposed support plates. The enclosure bars provide a framework for the fin assemblies and a support surface for attaching the manifolds to the core assembly. After the fin assemblies, support plates and enclosure bars are brazed together to form a unitary core assembly, the bars maintain proper separation of the support plates as well as allow attachment of the enclosure bars to the inlet and outlet manifolds
Apertures in the enclosure bars are aligned with apertures in the manifolds and connection members, allowing a plurality of fasteners to establish a mechanical connection between the manifolds and the enclosure bars, creating is a weld-free heat exchanger assembly. Eliminating the assembly weldment procedure reduces, or even eliminates, heat exchanger scrap and/or repair time and damage costs often imparted when welding a conventional core assembly. Furthermore, by eliminating the various welding operations needed to attach the core to the manifolds, a common occurrence of reduced structural rigidity of the material located near the weld is eliminated. In addition, replacing the manifold to core weld joint with a mechanical attachment can provides a more robust heat exchanger assembly with respect to the thermal stresses present at the joint.
While the need for welds on the brazed core and at the core to manifold joint are eliminated in the present invention, it is considered within the scope of the present invention to construct the core components prior to brazing and/or construct the manifolds from a number of separate pieces that are welded together. Further welding may be performed on the heat exchanger assembly, other than the core to manifold joint, after the mechanical attachment is achieved. Alternatively, apertures may be formed in the enclosure bars after the core is brazed to form a unitary assembly.
REFERENCES:
patent: 1831533 (1931-11-01), Hubbard
patent: 2828947 (1958-04-01), Hedbom
patent: 2834582 (1958-05-01), Kablitz
patent: 2953110 (1960-09-01), Etheridge
patent: 2961222 (1960-11-01), Butt
patent: 2983485 (1961-05-01), Peterson
patent: 3262496 (1966-07-01), Bawabe
patent: 3967354 (1976-07-01), Jaspers
patent: 3995688 (1976-12-01), Darm
patent: 4263966 (1981-04-01), Ostbo
patent: 4301863 (1981-11-01), Bizzaro
patent: 4308915 (1982-01-01), Sanders et al.
patent: 4442886 (1984-04-01), Dinulescu
patent: 4596285 (1986-06-01), Dinulescu
patent: 4714107 (1987-12-01), Adsett
patent: 4823867 (1989-04-01), Pollard et al.
patent: 4848450 (1989-07-01), Lapkowsky
patent: 4860824 (1989-08-01), Foley et al.
patent: 4987955 (1991-01-01), Bergqvist et al.
patent: 5183106 (1993-02-01), Stancliffe et al.
patent: 5383516 (1995-01-01), Dinulescu
patent: 5573060 (1996-11-01), Adderley et al.
patent: 5832993 (1998-11-01), Ohata et al.
Bolla James David
Kennedy Richard Brian
Honeywell International , Inc.
Lazarus Ira S.
McKinnon Terrell
Zak, Jr. Esq. William J.
LandOfFree
Weld-free heat exchanger assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Weld-free heat exchanger assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Weld-free heat exchanger assembly will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2442290