Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1 ~7 7631
METHOD OF M~KING A FACE TYPE SEAL E~ETW}3EN
MEMBERS OF A NONMOTION-q!RANSMITTING JOIN~
The present lnvention relates to seals.
Nonmotion-transmitting type face seals have typi-
cally been of two types in the prior art, namely, the pre-
formed gasket type and the formed-in-place liquid gasket.
The preformed gasket type typically employs a rubber-like
material, an asbestos material, or a ~ibrous cemented mat
material, each of which are cut to a predetermined shape
and subjected to pressure between parts to be sealed which
are independently clamped by mechanical means such as bolt
and nut fasteners. Several problems are currently asso-
ciated with such preformed gaskets, including (a) the
inability to accommodate tolerances between the surface
of the parts to be sealed and thus generally require smooth
machined sealing surfaces to seal properly (will not
accommodate cast surfaces which are of a relatively rough
nature), (b) the likelihood that the gasket material will
be abused prior to being assembled or in assembly thus
causing the seal assembly to malfunction, (c) poor sealing
effectiveness as a result of poor rigidity of the assembly
being sealed; (d) seal distortion in the joint area due to
assembly deformation, (e) dependency upon pressure to effect
the seal, not adhesion (seal is unable to add to the mech-
anical fastener effectiveness); (f) extrusion under theheavy pressure of mechanical fasteners which permits con-
tamination of the surrounding joint area, and (g) complexity
of design and generally higher cost per unit to employ.
The formed-in-place gaskets suffer from generally
the same problems recited for the preformed gaskets above,
except that problems (a) and (g) generally do nst apply.
However, certain additional problems arise in that it re-
quires a bac~up system for a shift change during vol~me
production in an assembly plant.
What is needed is a nonmotion-transmitting type
face seal which is capable of obviating all of the above
problems, and at the same time do so at a lower cost with
less complexity and reliability for high volume production
use.
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In accordance with one aspect of -the present
invention, there ls provided a method of making a face
type seal between members of a nonmotion transmltting
joint. At least one circuitous channel, having a single
access opening to the exterior of said joint for injecting
liquid sealant material into the channel, i9 provlded
on a joining surface of at least one of the surfaces
to be joined and sealed. With the members rigidly secured
together and in direct contact with each other, an injector
head is inserted into the access opening. The access
opening, if properly sized and/or shaped relative to
the injector head, will also provide exit means f~rom
the channel.
A pressurized supply of liquid sealant material is
lS delivered through an injector head into the channel
access opening to fill t~e channel and displace its con-
tents, ordinarily air. Unless the liquid sealant material
is introduced by metered injection and controlled so that
only an amount exactly measured to fill the channel is
introduced, the liquid sealant material will overflow from
the channel through channel exit means. Ordinarily,
the injector head would be withdrawn prior to curing of
the liquid sealant material.
After filling the channel with sealant material,
the injector head is removed and the liquid sealant material
in the channel is cured to a solid nonload-bearing consis-
tency which adheres to the members of the joint. Depen-
ding on the choice of liquid sealant material employed,
curing may be effected with the aid of reactant chemicals
or catalysts, or both, which may be injected into the
channel with the liquid sealant m~terial or placed in the channel
prior to introduction of the liquid sealant material
and by heat, irradiation, air drying, or any combination
of these means by techniques well known in the chemical
arts. The solid sealant material forms a continuous
pliable strand which adheres to the walls of the channel
carried by both the members. This continuous strand
will ordinarily encompass a zone of the joint ~or which
sealing is desired or required.
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In accordance with a further aspect of the invent-
tion, there is provided a face seal for nonmotion-transmit-
ting joint, ~the joint being comprised of a pair of mating
members having faces rigidly held in direct contact,
comprising: (a) walls in at least one of the members
defining a circuitous channel lying along the plane of
separation between the members and surrounding a zone
of the joint to be sealed; and tb) a continuous strand
of solid flexible sealant material in the channel adhering
to both the members.
The face type seal and method herein provide
several advantages, including: (a) considerably less
sealant material is required, compared to gasket or formed- -
in-place sealed joints, (b) less member weight is required
since large flange surfaces are no longer necessary to
support loading as in gasket sealed joints, (c) more
efficient seals are obtained in service when members
are subjected to stresses which disturb the rigidity
of prior art assemblies, (d) faster installation of the
: 20 seal assembly, and (e) reduced costs resulting from the
elimination of special finished sealing surfaces normally
required for other types of seals.
The invention is described further, by way of
illustration, with reference to the accompanying drawings,
in which:
Figure 1 is a plan view of a face type seal assembly
employing the invention herein;
Figure 2 is a sectional vie~ of the structure of
Figure 1 taken along line II-II;
.~ 30 Figure 3 is an enlarged elevational view of a
portion of the sealant groove and port, and illustrating
in detached relationship the applicator device employed
to be inserted within the groove and port;
Figure 4 is a plan view of the structure of Fisure 3
35 illustrating different operative`positions of the head;
Figures 5 through 8 illustrate, in series, different
operational positions of the applicator device as em.ployed
within the groove and port of the present invention; Figures
5 and 7 being elevational, and Figures 6 and 8 being plan
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views, respectively, ~or each o~ views 5 and 7;
Figures 9 through 12 are views similar, respectively,
to Figures 1 through 4, but depicting an alternative
em~odiment;
Figure 13 is an exploded view of still another
embodiment employing the principles of the present
invention;
Figures 14 and 15 are fragmentary enlarged views
: of portions of the view of Figure 13;
Figure 16 is a plan view of the sealing groove of
Figure 14; and
Figure 17 is an elevational view of the structure
of Figure 16.
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Referring to the drawings, a preferred method
- 15 for making a face type seal between members 12 and 14
r~ of a nonmotion-transmitting joint 9 having relatively
flat faces 11 and 13.to be sealed shall be described
in connection with the embodiment of Figures 1 through
; 8.
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(1~ A cixcuitous channel 10 is provided around a
zone of the joint to be sealed ~here being the interface
between flange 12b and member 14 outside of neck 12a).
The channel lays along the plane 8 of separation between
members 12 and 14. The channel in Figures 1 through 8
is defined by a groove machined lnto a face 11 of member 12
immediately outside of central neck 12a in a surrounding
flange 12b. The channel is completed by the face 13 of
member 14 which closes the groove when the members are
assembled in direct abutting or face-to-face contact
and rigidly secured by fasteners 15. ~he groove has a
semicircular cross-section (here dimensioned to have a
transverse diameter of about .07-.25"); the deepest part
of the groove will be called a valley. The groove is
continuous and circuitous, extending as closely adjacent
the mechanical fastening devices 15 (machine screws, rivets,
or bolts and nuts employed to maintain the members to-
gether) as permitted before the mating surfaces become too
irregular. In this case, the groove forms substantially
a square in plan view except for a slight arcuate radius
proximate each of the fastener devices.
(2) A single access opening 16 is defined through
member 12 extending from surface 12c of flange 12b to a
depth to interconnect with channel 10. As shown in Figure 1,
the access opening is a cylindrical port located at a mid-
point position along one of the sides of the groove square
and has a diameter larger than the diameter of said groove.
The port extends to a depth where it intersects the valley
of the groove thereby defining a rectangular communicating
aperture 17 between the cylindrical port and the groove.
(3) An injector head 18 is inserted into said
access opening 16, through aperture 17 into the channel 10
to interrupt the circuitous channel and divide it. The
division defines a channel entrance 27 and a channel exit
28 juxtaposed to each other. The division is facilitated
by the use of a dam element 19 formed as a projection on
the end of the injector head, such projection having a
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elevation complimentar~ to the g~oove and a rectangular
cross-section (see Figure 5). The projection is dimen-
sional to fit comfortably through the rectangular aperture
17 between the groove and port (the length 21 of the pro-
jection is slightly shorter than length 26 of the aperture
and the width 20 of the projection i5 sized to be slightly
shorter than the width 21 of the aperture, see Figures 3,
5 and 6). After insertion or penetration of the projection
~` 19 into the groove through said aperture 17 to the member
14 (see position l9a of Figures 4 and 6), the projection
is turned 90 to form a dam or blockage across the channel
(see position l9b of Figures 4 and 8). This, of course,
~- requires that the projection have a shape in elevation
substantially identical to the interior cross-sectional
shape 23 of the groove. When the applicator device has
been rotated to the dividing position l9b, a supply channel
24 through the applicator device will then be in communica-
tion with the channel entrance 27 (one divided part).
, Likewise, an overflow channel 25, also in the applicator
device, will then be in communication with the channel exit
28 (the other divided part).
(4) Power means 29 is employed to delive- a pres-
surized liquid sealant material to the injector head and
through said supply channel into said channel entrance to
displace the air content of the channel. As the liquid is
; forced into the channel, it flows throughout the continuous
circuit fully occupying same and passes through the channel
exit through the overflow channel 25 of the injector head
and out through the access opening.
The sealant material is selected as one which is
liquid at room temperature (20C) and can be heat or chemi-
cally cured to a solid nonload-bearing substance after
installation and which adheres to the walls of the channel
` in such solid condition. Some plastic copolymers can be
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heated to achieve such solid phase ~known as one part
sealants), others are mixed with a chemical activator at
the time of injection (known as two part or multiple part
sealants). Examples of suitable sealant materials comprise
elastomeric silicones, neoprene or natural rubber, uret~ane,
~Al or commercial preparations such as Hypalon~which comprises
chlorosulfonated polyethlene,made by DuPont, Nitrile ~a syn-
thetic rubber) which comprises acrylonitrile -butadiene
hompolymer,made by B.F. ~oodrich, SBR which comprises styrene
butadiene homopolymer (a synthetic rubber) made by Goodyear
and others, and EPDM which comprises terpolymer of ethylene,
propalene and diene ~ith the unsaturated residual portion of
the diene in the side chain, made by DuPont.
The sealant material is selected also as to vis-
cosity in accordance with the joint design demands. If
the channel must be of considerable length to meet design
requirements, a low viscosity (1,000-60,000 cps) liquid
sealant material is used. If the channel length is short
or channel surface is smooth, a higher viscosity sealant
can be used (60,000-150,000 cps). The material should
preferably not undergo more than 2% shrinkage in curing
to a solid in order to maintain a high efficiency seal and
adhesive attachment. The resulting solid must be suffi-
ciently elastomeric to provide a seal under the dynamic
joint conditions to be experienced; this will require an
elongation in such material of normally 18-25~, but in
- extreme cases it may be up to 200~.
The pressure required to iniect the sealant
material will vary with the application. With low channel
friction or low viscosity sealant materials, the pressure
may range from 2-lO0 psi; and with higher channel friction
or higher viscosity materials, the pressure may range as
high as 4,000-5,000 psi. It is important that the members
be positively held together to resist parting and extrusion
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o~ the sealant material out of the grooves. This may re-
quire typically 2-10 inch pounds of torque on the threaded
fasteners.
(5) ~fter completely filling the interior volume
of the channel, the iniector head is rotated back to the
position of Figures 5 and 6 and is withdrawn. The pro-
jection 19 is taken out through the aperture 17 severing
the supply sealant material from the injected or filled
sealant material. As the head is gradually withdrawn, a
slight amount of sealant material is added to the port to
occupy the space now vacated by the injector head. The
channel thus remains totally filled with sealant material
which is liquid. The liquid sealant is cured to a solid
phase forming a continuous circuitous strand in the channel.
As shown in Figures 9 through 12, the principles of
this invention can be applied to flat single ply plates,
one of which can be deformed to form a channel equivalent
to the channel groove of the preferred embodiment. Again,
an injector head 30 is employed having a projection or dam
element 31 which is complimentary in shape to the interior
cross-sectional shape of the channel 32 formed by the
deformed flat plate 33. Upon insertion of the projection
31 through the rectangular aperture 34, the injector head
may be rotated to bring the dam 31 into a full dividing
position. The injection of liquid sealant material can
be made through a supply channel 35 as in the preferred
embodiment. The pl~tes of the assembly are clamped to-
gether in direct contact by suitable rastening means such
as rivets at 7.
Figures 13 through 17 represent still another
embodiment whereby the principles of the invention can be
applied utilizing as a series of grooves or utilizing
overlapping continuous grooves which surround several
critical ports or passages in the part to be assembled.
11'776;~1
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In this embodiment, an exhaust gas recirculation valve 40
is mounted to a carburetor spacing element 41 with an ex-
haust gas recirculation cooler device 42 interposed there-
between. As shown in Figure 14, valve 40 has two ports
43 and 44 with centers thereof spaced apart. The face 46
of valve 40 is mated flush against a side 42a o~ the
cooler device 42. The surfaces are aligned and maintained
in solid contact by fastening means 65 consisting of
threaded studs 65a and nuts 65b. To maintain a sealed
relationship between surfaces 42a and 46, a series of
separated circular grooves (here 39 and 47) are defined
in surface 46, each respectively surrounding ports 43 and
44. Separate access openings in the form of short grooves
60 and 61 are also defined in surface 46. Narraw circular
lS lands 66 and 67 separate the respective ports from the
grooves. A common injector head (not shown) is used to
feed the grooves 39 and 47 simultaneously when the joint is
assembled. The single injector head carries a pair of
projections which when inserted into the short access
~ 20 opening grooves will interrupt each of the circuitous
;~ grooves so that supply and overflow channels of the in-
jector head in each of said grooves 60 and 61 may introduce
and form sealant rings. Thus, the use of a series of
separate circuitous channels fed by a common injector head
has obvious advantages for installation.
In Figures 15 through 17, the sealing relationship
is maintained by use of overlapping circuitous channels
63 and 64 fed by a common injector head 52. The channels
are defined by circular grooves in surface 62 of the space
element 41 around each of the ports 48 and 49, respectively.
., The grooves are closed by surface 42b of the cooler device.
The grooves meet at a juncture zone 51 therebetween. A
single access opening 50 is defined in surface 62 as a
short groove extending from edge 62a along said surface to
intersect both ring grooves at 51 (the overlapping zone).
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Thus, when the in~ector head 52 ~see Flgures 16-17) is
inserted into the access opening S0, the dam element 53
or projecting portion contacts the lands S4 and 55 respec-
tively separating the grooves from ports 48 and 49. The
projection 53 interrupts the figure eight groove configura-
tion into two parts whereby the supply channel 35 communi-
cates with the channel entrance ~one divided part) and the
overflow channel 36 communicateæ with the channel exit
(the other divided part). The ports in this embodiment
have a diameter of about 175 inches and the lands 54-55
each are limited to about .05 inches wide. The ring
grooves 63 and 64 have a width dimension of about .125
inches and .06 inches deep.
Significant weight reduction and cost savings
was achieved by the embodiments of Figures 13-17. Both
the space element casting and the valve housing were
reduced in size by elimination of the need for large flange
surface area to accommodate a gasket. A stainless steel
plate attached to the opposite faces of the cooler device
to provide flat mounting surfaces for ~he gaskets was
eliminated.
