Heat exchange – Flow passages for two confined fluids – Interdigitated plural first and plural second fluid passages
Reexamination Certificate
2000-02-04
2001-03-13
Lazarus, Ira S. (Department: 3743)
Heat exchange
Flow passages for two confined fluids
Interdigitated plural first and plural second fluid passages
C165S166000
Reexamination Certificate
active
06199626
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to heat exchangers of the type formed of stacked plates, wherein the plates have raised peripheral flanges that co-operate to form an enclosure for the passage of heat exchange fluids between the plates.
The most common kind of plate type heat exchangers produced in the past have been made of spaced-apart stacked pairs of plates where the plate pairs define internal flow passages therein. The plates normally have inlet and outlet openings that are aligned in the stacked plate pairs to allow for the flow of one heat exchange fluid through all of the plate pairs. A second heat exchange fluid passes between the plate pairs, and often an enclosure or casing is used to contain the plate pairs and cause the second heat exchange fluid to pass between the plate pairs.
In order to eliminate the enclosure or casing, it has been proposed to provide the plates with peripheral flanges that not only close the peripheral edges of the plate pairs, but also close the peripheral spaces between the plate pairs. One method of doing this is to use plates that have a raised peripheral flange on one side of the plate and a raised peripheral ridge on the other side of the plate. Examples of this type of heat exchanger are shown in U.S. Pat. No. 3,240,268 issued to F. D. Armes and U.S. Pat. No. 4,327,802 issued to Richard P. Beldam.
A difficulty with the self-enclosing plate-type heat exchangers produced in the past, however, is that the peripheral flanges and ridges form inherent peripheral flow channels that act as short-circuits inside and between the plate pairs, and this reduces the heat exchange efficiency of these types of heat exchangers.
SUMMARY OF THE INVENTION
In the present invention, ribs and grooves are formed in the plates inside the peripheral flanges and ridges, and these ribs and grooves act as barriers to reduce short-circuit flow on one side of the plates and promote flow on the other side of the plates to improve the flow distribution between the plates and the overall heat exchange efficiency of the heat exchangers.
According to one aspect of the invention, there is provided a plate type heat exchanger comprising first and second plates, each plate including a planar central portion, a first pair of spaced-apart bosses extending from one side of the planar central portion, and a second pair of spaced-apart bosses extending from the opposite side of the planar central portion. The bosses each have an inner peripheral edge portion and an outer peripheral edge portion defining a fluid port. A continuous ridge encircles the inner peripheral edge portions of at least the first pair of bosses and extends from the planar central portion in the same direction and equidistantly with the outer peripheral edge portions of the second pair of bosses. Each plate includes a raised peripheral flange extending from the planar central portion in the same direction and equidistantly with the outer peripheral edge portions of the first pair of bosses. The first and second plates are juxtaposed so that one of: the continuous ridges are engaged and the plate peripheral flanges are engaged; thereby defining a first flow chamber between the engaged ridges or peripheral flanges. The fluid ports in their respective first and second pairs of spaced-apart bosses are in registration. A third plate is located in juxtaposition with one of the first and second plates to define a second fluid chamber between the third plate and the central planar portion of the adjacent plate. Also, each planar central portion includes a barrier formed of a rib and complimentary groove. The rib is located between the inner peripheral edge portions of the bosses of one of the pairs of bosses to reduce short-circuit flow therebetween. The complimentary groove is also located between the bosses of the one pair of bosses to promote flow therebetween.
REFERENCES:
patent: 3240268 (1966-03-01), Armes
patent: 4327802 (1982-05-01), Beldam
patent: 4592414 (1986-06-01), Beasley
patent: 4696342 (1987-09-01), Yamauchi et al.
patent: 5222551 (1993-06-01), Hasegawa et al.
patent: 5291945 (1994-03-01), Blomgren et al.
patent: 5307869 (1994-05-01), Blomgren
patent: 5884696 (1999-03-01), Loup
patent: 163069 (1954-03-01), None
patent: 0 742 418 A2 (1996-11-01), None
patent: 611941 (1994-08-01), None
Evans Bruce L.
Lemczyk Thomas F.
So Allan K.
Wu Alan K.
Duong Tho
Lazarus Ira S.
Long Manufacturing Ltd.
Ridout & Maybee
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