Note: Descriptions are shown in the official language in which they were submitted.
CA 02504758 2005-04-20
SLIDE-IN FLAPPER VALVES
FIELD OF THE INVENTION
This invention relates to valves, and in particular, to flapper valves.
BACKGROUND OF THE INVENTION
Automotive fluids, such as engine oil or transmission fluids, absorb heat in
use.
To prevent fluid deterioration, this heat often needs to be removed. Heat
exchangers are commonly used for this purpose. Moreover, heat exchangers are
known to perform this function adequately in moderate ambient conditions.
However, in cold ambient conditions, engine oils and transmission fluids can
be
highly viscous. In such conditions, automotive fluids can be relatively
indisposed
to flow through heat exchangers. As a result, in such conditions, the
interposition of a heat exchanger in an oil circuit can disadvantageously
impede
circulation. Starvation of some downstream components, like transmissions,
may even occur.
In order to avoid these adverse effects, it is known to provide a mechanism
for
bypassing the heat exchanger. One way that this has been done in the past is
to provide a bypass conduit. The bypass conduit is connected in parallel with
the heat exchanger and has a relatively low resistance to the flow of high
viscosity fluids as compared to the heat exchanger. Structures of this type
are
known to avoid starvation of downstream components, but can suffer in that, in
normal operating conditions, the flow is split between the heat exchanger and
the bypass circuit. This requires that the heat exchangers be made
proportionately larger and heavier to achieve the same overall heat exchange
performance for the cooling system. This added size and weight, and the added
costs associated therewith, are undesirable to automotive manufacturers.
To ameliorate the split-flow problem, it is known in the prior art to provide
bypass valves. Sometimes, these bypass valves are pressure-activated, and are
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built into the heat exchanger. A heat exchanger exemplary of the foregoing is
shown in United States Patent No. 5,499,675 (Haasch et al.), issued March 19,
1996. This structure includes a flapper valve of spring steel biased in a
closed
position, to prevent bypass flow, and which is adapted to be urged open when
the fluid pressure inside the heat exchanger exceeds a certain limit, as
indicative
of cold-start conditions. Heat exchangers of this general type can avoid
starvation of downstream lubricated components, and can be adapted such that
bypass flow is substantially nil in normal operating conditions, thereby to
permit
compact heat exchanger construction. However, in Haasch et al, the flapper
valve is rather delicate and exposed while the heat exchanger is being mounted
to the engine block, using an extension of the oil return pipe. The flapper
valve
is prone to suffering damage or being dislodged during installation. Also,
heat
exchangers of this type cannot be modified easily to accommodate different
mounting or performance requirements in modern automotive applications.
It is also known to provide heat exchangers including a domed filter plate and
a
snap-in valve clip. Structures of this type are described in United States
Patent
No. 4,561,494 (Frost), issued December 31, 1985; United States Patent No.
5,588,485 (Gire), issued December 31, 1996; and United States Patent No.
5,765,632 (Gire), issued June 16, 1998. While the flapper valves in these
structures are less prone to damage or dislodgement during heat exchanger
installation, these heat exchangers are relatively inflexible in terms of the
location of the bypass apertures or the size or shape of the oil filter that
can be
used with them.
SUMMARY OF THE INVENTION
In the present invention, a compact, low-profile flapper valve assembly is
provided. The flapper valve assembly utilizes a slide-in flapper valve, and
can
be readily attached to any heat exchanger or other fluid device having a flow
chamber communicating with the flapper valve assembly. The flapper valve
assembly provides for selective flow from the flow chamber, and can be
conveniently configured to accommodate different mounting or performance
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requirements in modern automotive applications.
According to one aspect of the invention, there is provided a flapper valve
assembly for use with a fluid device having a flow chamber. The flapper valve
assembly comprises a shim plate having a fluid port therethrough for
communication with the flow chamber. A face plate overlies the shim plate and
has an outlet port communicating with said fluid port. The shim plate and the
face plate define a slot located between the shim plate and the face plate.
The
slot extends between one of the fluid and outlet ports and the periphery of at
least one of the shim plate and the face plate. A flapper valve has a first
portion
slidably located in the slot, and a flexible second portion movable from a
first
position where the second portion at least partially blocks flow through the
fluid
port, to a second position where the second portion unblocks flow through the
fluid port. Flapper gripping means are provided for locking the first portion
against movement in the slot. Bias means are provided for urging the second
portion into the first position.
According to another aspect of the invention there is provided a heat
exchanger
for use with a lubrication circuit for mechanical components and with a spin-
on
oil filter. The heat exchanger comprises a heat exchange element and a flapper
valve assembly. The heat exchange element includes an inlet manifold. The
flapper valve assembly includes a shim plate attached to the heat exchange
element, the shim plate having a fluid port therethrough communicating with
the
inlet manifold. A face plate overlies the shim plate and has an outlet port
communicating with the fluid port. The face plate also has a sealing surface
adapted to be engaged by the filter for delivering oil to the filter from the
outlet
port. The shim plate and the face plate define a slot located between the shim
plate and the face plate. The slot extends between one of the fluid and outlet
ports and the periphery of at least one of the shim plate and the face plate.
A
flapper valve has a first portion slidably located in the slot, and a flexible
second
portion movable from a first position where the second portion at least
partially
blocks flow through the fluid port, to a second position where the second
portion
unblocks flow through the fluid port. Flapper gripping means are provided for
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locking the first portion against movement in the slot. Bias means are
provided
for urging the second portion into the first position.
Advantages, features and characteristics of the present invention, as well as
methods of operation and functions of the related elements of the structure,
and
the combination of parts and economies of manufacture, will become apparent
upon consideration of the following detailed description of the preferred
embodiments, with reference to the accompanying drawings, the latter of which
is briefly described hereinafter.
BRIEF DESCRIPTION OP THE DRAWINGS
In the accompanying drawings, which are for the purpose of illustration and
description only, and are not intended as a definition of the limits of the
invention:
Figure 1 is a perspective view of an assembly including a heat exchanger and a
spin-on oil filter, the heat exchanger including a flapper valve assembly
according to a preferred embodiment of the present invention;
Figure 2 is an exploded view of the structure of Figure 1;
Figure 3 is an exploded view of the structure in encircled area 3 in Figure 2;
Figure 4 is an enlarged perspective view of the flapper valve as indicated in
encircled area 4 in Figure 3;
Figure 5 is a top plan view of the structure of Figure 4;
Figure 6 is a side elevational view of the structure of Figure 4;
Figure 7 is a top plan view of the heat exchanger as indicated in encircled
area 3
in Figure 2;
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Figure 8 is a partial cross-sectional view taken along lines 8-8 of Figure 7,
with
the second portion of the flapper valve disposed at a closed position;
Figure 8A is a view similar to Figure 8, with the second portion of the
flapper
valve disposed at an open position;
Figure 9 is a partial cross-sectional view taken along lines 9-9 of Figure 7;
Figure 10 is a view similar to Figure 7, with the flapper valve about to be
inserted into the heat exchanger;
Figure 11 is a partial cross-sectional view taken along lines 11-11 of Figure
10;
Figure 12 is a view similar to Figure 10, but with the flapper valve partially
inserted into the heat exchanger;
Figure 13 is a partial cross-sectional view taken along lines 13-13 of Figure
12;
Figure 14 is a view similar to Figures 10 and 12, but with the flapper valve
fully
inserted into the heat exchanger;
Figure 15 is a view similar to Figures 10, 12 and 14, but showing a further
preferred embodiment of the invention;
Figure 16 is a partial cross-sectional view taken along lines 16-16 of Figure
15;
Figure 17 is a view similar to Figure 15, but with the flapper valve partially
inserted into the heat exchanger;
Figure 18 is a partial cross-sectional view taken along lines 18-18 of Figure
17;
Figure 19 is a view similar to Figures 15 and 17, but with the flapper valve
fully
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inserted into the heat exchanger; and
Figure 20 is a partial cross-sectional view taken along lines 20-20 of Figure
19.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figure 1 shows a heat exchanger 22 having a spin-on oil filter 24 or similar
fluid
device mounted thereon. Heat exchanger 22 includes a flapper valve assembly
20 according to a preferred embodiment of the present invention, and a heat
exchanger element 28. Heat exchanger 22 preferably is in the form of donut-
type oil cooler, but it could be any other type of heat exchanger or any other
type of fluid device. For the purposes of the present specification, the exact
form of the heat exchanger element 28 and the spin-on oil filter 24 is not
considered to be part of the present invention.
The heat exchanger or donut-type cooler 22 is for use with a coolant circuit
and
a lubrication circuit for mechanical components and, by way of example, as
indicated in Figure 2, is mounted on a threaded tube or pipe 26 attached to an
engine block 27 (only partially shown). Threaded pipe 26 extends through a
2o clearance opening or hole 40 in heat exchanger 22 to permit the subsequent
threaded attachment of the oil filter 24 onto pipe 26, as indicated in Figure
1,
and also to hold heat exchanger 22 in place on engine block 27.
As best seen in Figure 3, heat exchange element 28 has an end plate 31, to
which flapper valve assembly 20 is attached. Heat exchange element 28 is of
the stacked-plate type and has a coolant inlet 30 and a coolant outlet 32.
Heat
exchange element 28 is formed of a plurality of aluminum plates brazed
together. Each plate has spaced apart, arcuate openings therein, which are
aligned to form respective flow passages or chambers or manifolds 34, 36. One
of these manifolds can be an inlet manifold, for example, manifold 34. The
other
of them can be an outlet manifold 36, but this flow direction could be
reversed.
Where flow chamber or manifold 34 is the inlet manifold, oil is received into
the
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manifold 34 through an aperture 37 formed in engine block 27 (see Figure 2).
This oil passes through heat exchange element 28 to outlet manifold 36, and
then passes upwardly into oil filter 24, and finally down through pipe 26 to
be
returned to engine block 27. However, where this flow is reversed, (hereafter
referred to as the reverse flow direction), it comes up through pipe 26 to
filter
24, and then passes through manifold 36 to manifold 34 and then goes back
through aperture 37 to be returned to the engine. In this latter case,
manifold
36 would be the inlet manifold and manifold 34 would be the outlet manifold of
heat exchange element 28.
It should be understood that the heat exchange element 28 is of generally
conventional construction, and therefore, only those parts necessary for an
understanding of the present invention are shown in the figures and described
herein.
Upon a flow of heated oil being forced into the inlet manifold 34 and a flow
of
coolant being delivered to the coolant inlet 30, a flow of cooled oil is
produced at
the outlet manifold 36 and a flow of heated coolant is produced at the coolant
outlet 32.
Flapper valve assembly 20 has a shim plate 46 and an overlying face plate 48
secured to one another and together defining part of clearance opening 40
adapted for receiving the threaded pipe 26.
The shim plate 46, which is stamped from an aluminum alloy and secured, by
brazing, to end plate 31 of heat exchange element 28, is provided with an
aperture 50 and a passage-forming portion 52. Aperture 50 is in communication
with the outlet manifold 36. The passage-forming portion 52 defines a fluid
passage or port 54 in communication with the inlet manifold 34 and spaced from
the clearance opening or hole 40. For greater clarity, it should be understood
that the passage-forming portion 52 in this embodiment is a generally annular
portion of the shim plate 46 immediately surrounding the fluid port 54.
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The face plate 48, which is formed of aluminum and secured by brazing to shim
plate 46, has a sealing surface 56 adapted to be engaged by the filter 24.
Face
plate 48 has a pair of fluid outlet ports 60, 62 (or inlet ports where the
flow
direction is reversed, as discussed above) for delivering oil to filter 24.
One
outlet port 60 is in communication with the aperture 50, thereby to
communicate with the outlet manifold 36. The other outlet port 62
communicates with fluid port 54. Shim plate 46 and face plate 48 define
therebetween a slot 66 machined into the underside of the face plate 48. Slot
66 extends between the outlet port 62 and the periphery of at least one of the
shim plate 46 and the face plate 48. For example, in the embodiment shown in
Figure 3, slot 66 extends radially inwardly to the periphery of clearance
opening
40, which is also at the inner periphery of both the respective shim and face
plates 46, 48. However, slot 66 could extend radially outwardly in the
opposite
direction from the outlet port 62 to the outside peripheral edges of the shim
and
face plates 46, 48, if desired. Slot 66 could be formed in shim plate 46
instead
of face plate 48, or it could be formed partially in both the shim and face
plates
46, 48. In these latter configurations, appropriate modifications of the
outlet
port 62 and fluid port 54 would be required to accommodate the positioning of
flapper valve 42, as will be appreciated by those skilled in the art. Also,
where
slot 66 extends to the outside peripheral edges of the shim and face plates
46,
48, the outside peripheral edges would need to be sealed to prevent leakage
from the heat exchange element through slot 66. As it is, some leakage from
slot 66 into clearance opening 40 could occur if slot 66 is not completely
blocked
by pipe 26, but this leakage would be insignificant.
The flapper valve assembly 20 further includes a flexible, resilient flapper
or
flapper valve 42. As seen best in Figures 4 to 6, flapper valve 42 is
constructed
out of a bowed strip of resilient spring material, namely, spring steel.
Flapper
valve 42 has a first portion 68, a second portion 70 and an intermediate
portion
72 extending between the first portion 68 and the second portion 70. The first
portion 68 is slidably located in slot 66 in an operative position within slot
66.
While the first and intermediate portions 68, 72 could be relatively rigid,
second
portion 70 is flexible to act as a valve, as discussed below.
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At the operative position of the first portion 68, the second portion 70 is
movable, by flexure, between a first or closed position, abutting the passage-
forming portion 52, to at least partially block flow through the fluid port
54, as
shown in Figure 8, to a second or open position, spaced from the passage-
forming portion 52, as shown in Figure 8A, where flow through fluid port 54 is
unblocked. The second portion 70 is dimensioned to restrict flow through the
fluid port 54, either fully or partially, when disposed at its first or closed
position.
i0 Outlet port 62 in mounting or face plate 48 is dimensioned to be a
clearance
opening to permit full movement of the flapper valve second portion 70 to the
second or open position. However, the peripheral edges of outlet port 62 could
be configured to overlap and limit the opening of flapper valve 42, if
desired.
As is evident from a comparison of Figures 6 and 8, the flapper valve 42 is
flattened somewhat to fit into slot 66 in its operative position, and is
thereby
spring-loaded and frictionally held in slot 66. A crest 41 on the flapper
valve 42,
(see Figures 4 to 6) bears against the underside of the slot 66, adjacent to
the
periphery of fluid port 62. In this preferred embodiment, the slot 66 and the
clearance opening 40 are adapted to permit the first portion 68 to be
operatively
positioned by firstly inserting the flapper valve second portion 70 through
the
clearance opening 40 into the slot 66, as indicated by the sequence of Figures
10
to 14. Arrow 74 in Figure 10 shows the direction of insertion. The first
portion
68 is flared so as to define at least one and preferably two opposed
transverse
protuberances 71, best seen in Figures 4 and 5, which engage corresponding
notches 66a in slot 66, as seen best in Figure 12, when the first portion 68
is
operatively positioned, thereby to correctly position and align flapper valve
42 in
slot 66 and avoid over-insertion of flapper valve 42. Protuberances 71 could
be
perpendicular to first portion 68, if desired, in which case notches 66a would
be
modified accordingly.
Flapper valve 42 also includes a staked tab 44 formed in or adjacent to crest
41
to engage the peripheral edge 43 (see Figure 8) of outlet port 62 in face
plate
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48, and lock the flapper valve 42 against extraction from the slot 66. The
friction fit of flapper valve 42 in slot 66, as well as protuberances 71 and
tab 44
form flapper gripping means for locking the flapper first portion 68 against
movement in slot 66. The spring flapper valve also constitutes bias means for
urging the flapper valve second portion 70 into the second or closed position.
In a further preferred embodiment, shown in Figures 15 to 20, otherwise
substantially identical to the preferred embodiment illustrated in Figures 1-
14
and numbered commonly, the flapper gripping means includes a detent 76
i0 positioned within the slot 66, instead of a staked tab 44. Detent 76 is
adapted
to bear against the first portion 68 of the flapper valve 42 when operatively
positioned, to correctly position flapper valve 42 in slot 66 and lock same
against
extraction from the slot 66. The detent 76 in this embodiment is an upturned
tab or flange formed in shim plate 46. As best illustrated in Figure 15, the
first
portion 68 is provided with a cut-out 78, in which detent 76 sits when the
first
portion 68 is operatively positioned. Such a cut-out 78 provides a pair of
spaced
legs 80, which may be utilized to urge the flapper valve 42 into position. As
best
illustrated in the sequence of Figures 15 to 20, the flapper valve 42 of this
further preferred embodiment rides in slot 66 over the detent 76 during
insertion. Once first portion 68 reaches the operative position, bias provided
by
the intermediate portion 72 urges the first portion 68 against the lower wall
defining slot 66, such that flapper valve 42 snaps into position and the
detent 76
nests into the cut-out 78.
In normal operating conditions, wherein relatively warm, substantially free-
flowing oil is delivered to the inlet manifold 34, the flow resistance through
donut cooler 22 is relatively low, such that the bias provided by the
intermediate
portion 72 maintains the second portion 70 of the flapper valve 42 against the
passage-forming portion 52 to restrict, and more specifically, substantially
arrest
flow through the fluid port 54. Thus, most of the flow arriving at the inlet
manifold 34 passes through the heat exchange element 28 to the outlet manifold
36, transferring heat in the process, prior to passing through fluid port 60
in the
face plate 48 to the oil filter 24, for filtration and subsequent return to
the oil
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circuit in a conventional manner.
In contrast, in normal high-pressure transient conditions, such as are present
in
the context of an engine start in relatively cold ambient conditions, wherein
the
oil is relatively cold, viscous oil is delivered to the inlet manifold 34 and
the
pressure in manifold 34 is relatively high. As a result, the viscous oil
forces the
second portion 70 of the flapper valve 42 to the open position, spaced from
the
passage-forming portion 52, as indicated by the sequence of Figures 8,8A, such
that sufficient by-pass flow passes from the inlet manifold 34 to port 62
directly
to the filter 24, through the fluid port 54. Periodic, momentary burst flows
caused by high-pressure spikes in the oil circuit also bypass the heat
exchange
element 28 in this manner.
The mechanical properties of the flapper valve 42 are selected to suit the
operating parameters of the heat exchange element and lubrication circuit with
which it is used, and in particular, flapper valve 42 has a spring constant
such
that it will open under predetermined pressure conditions.
The foregoing structure is of particular advantage, in that it obtains
relatively
2o high cooling performance in normal operating conditions, when cooling is
needed, as substantially all the oil passes through the heat exchange element.
At the same time, the structure avoids starvation of mechanical components in
normal transient high pressure conditions, such as cold weather startup, and
also avoids metal fatigue that can result from pressure spikes in the thin-
wall
plates forming the heat exchange element or oil cooler, since in such
conditions
bypass flow occurs.
Having described preferred embodiments of the present invention, it will be
3o appreciated that various modifications may be made to the structures
described
above without departing from the spirit or scope of the invention.
Foremost, whereas the flapper valve assembly of the present invention is shown
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attached to a heat exchanger in each of the preferred embodiments illustrated,
it
should be understood that the invention is not so limited, and may be deployed
in association with any fluid device having a flow chamber from which
intermittent bypass flow is desired.
It should also be understood that whereas the disclosure illustrates and
describes a heat exchanger of specific construction, modifications therein are
also contemplated to fall within the scope of the invention. Heat exchangers,
for
example, that are not of the donut type may be utilized.
As well, the heat exchangers need not be formed of stacked plates, nor is it
required that the various components be brazed to one another.
Where the heat exchanger is used with an oil filter and the flow direction is
reversed, i.e., where the oil goes through the oil filter first and then the
heat
exchanger, flapper valve assembly 20 would be positioned upside down, so that
the flapper valve second portion opens downwardly toward manifold 34.
It will also be appreciate that the flapper valve could be inserted into the
valve
assembly 20 by inserting it first through outlet port 62 and then into slot
66. In
this case, the flapper valve second portion 70 could be made larger, as could
the
bypass fluid port 54. Appropriate modifications would be made to the structure
described above for retaining the flapper valve in position.
As a further modification, whereas the flapper valve of the preferred
embodiment consists of a strip of simple spring steel, a resilient bimetallic
strip
could be readily substituted therefor. For example, a bimetallic flapper valve
could open in cold conditions to give bypass flow even if the pressure was not
excessive, and close in warm conditions to give pressure relief as needed. Of
3o course, a bimetallic flapper valve would still have a flexible second
portion and
provide pressure spike protection even in warm flow conditions.
As well, whereas in the preferred embodiments illustrated, the flapper valve
is
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adapted to substantially arrest flow when the second portion thereof is
disposed
at its closed position, this need not be the case. The second portion could,
for
example, be sized to only partially cover the fluid passage, thereby to permit
a
measure of bypass flow at all times.
From the foregoing, it will be evident to persons of ordinary skill in the art
that
the scope of the present invention is limited only by the accompanying claims,
purposively construed.
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