CA1177631A - Method of making a face type seal between members of a nonmotion-transmitting joint - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A face type seal between mating members is disclosed including the method of forming. A continuous groove is defined in the face of at least one of said members forming a continuous circuit in cooperation with said other member.
A single access opening is defined through one of the members communicating with said groove. The intersection of said access opening and groove defining a mouth opening.
A sealing material injector head is inserted through said access opening and mouth opening and positioned to in-terrupt said groove to define a groove entrance and a groove exit. A low shrinkage liquid sealant material is forced from a supply channel in the injector head into the groove entrance to displace air throughout said groove and overflow, if necessary, through said groove exit into an excess channel. The sealant material is cured to a re-silient nonload-bearing solid adhesively joining said members and effecting a resilient seal therebetween.

Description

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.

~ 7 _~ 3 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 i.'. .

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.t77 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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11'776~1 (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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, , 7'7~3 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 77f~31 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 ., . ~ ~ra~Qe ~n q f~k .

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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 g 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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, , i~77~31 `~ -10-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.

Claims (21)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS

1. A method of making a face type seal between members of a nonmotion-transmitting joint, the steps comprising:
(a) providing at least one circuitous channel on a joining surface of at least one of the surfaces to be joined and sealed;
(b) providing a single access opening to said channel;
(c) with said members rigidly secured together, inserting an injector head into said access opening into said channel to interrupt said channel for defining a channel entrance and a channel exit juxtaposed thereto;
(d) delivering a pressurized supply of liquid sealant material through said injector head into said channel entrance to displace the contents of the channel; and (e) after filling said channel with sealant material, removing the injector head and curing said sealant material to a solid nonload-bearing consistency which adheres to said members.

2. The method as in claim 1, in which: in step (e) additional sealant material is delivered to the space occupied by said injector head in said members as said injector head is withdrawn.

3. The method as in claim 1, in which: said sealant material is selected from the group comprising elastomeric silicones, neoprene or natural rubber, urethane and chemical or heat curing polymer plastics having adhesive qualities in the solid phase.

4. The method as in claim 1, in which: said sealant has a viscosity of 1,000-150,000 centipoise when in the liquid phase.

5. The method as in claim 1, in which: said sealant material undergoes no greater than 2% shrinkage in being cured to said solid.

6. The method as in claim 1,, in which: an overflow channel is defined with said access opening, and in step (e), sealant material in said overflow channel is drawn by surface tension to occupy the space vacated by said injector head.

7. The method as in claim 1, in which: in step (a) a plurality of circuitous channels are commonly connected to said single access opening for common delivery and overflow of sealant material.

8. The method as in claim 1, in which: a plurality of circuitous channels are defined and arranged to overlap at a common juncture, said injector head insertion causing said channels to be connected in series thereby forming one continuous channel.

9. The method as in claim 1, in which: the face area of said members outside of said channel is limited to a narrow land with a width no greater than .05 inches.

10. The method as in claim 1, in which: said channel is defined in part by a groove in the face of one of said members and in part by the face of the other member covering said groove.

11. The method as in Claim 1, in which: said members are comprised of single ply sheet metal members, said members being deformed out of the plane of said sheet to define said channel.

12. A method of making a face type seal for interconnecting members, comprising the steps of:
(a) providing a pair of abutting members to be sealed when assembled;
(b) defining a groove in the face of one of said members, said groove forming a continuous circuit;
(c) forming a single access opening in at least one of said members intersecting with the valley of said groove to define a mouth opening dimension to be smaller than any dimension of said groove;
(d) filling said groove with a liquid sealant material curable to a solid nonload-bearing consistency, said filling being carried out by the use of an injector head carrying a dam element insertable through said single access opening and mouth opening and rotatable to a position to separate said groove into two parts, said injector head having a supply channel for introducing said liquid sealant material to one part of said divided groove and an overflow channel for receiving the excess of the injected sealant material from the other part of said divided circuit; and (e) after filling said groove, rotating said in-jector head to a position where said dam element is aligned with said mouth opening and withdrawing said injector head.

13. The method as in Claim 12, in which: said liquid sealant material is converted o said solid con-sistency by the application of heat.

14. The method as in claim 12, in which: said liquid sealant material is comprised of chemically reactive ingredients which when mixed and placed in said groove form a pliable nonload-bearing solid within a predetermined period.

15. A face seal for nonmotion-transmitting joint, said joint being comprised of a pair of mating members having faces rigidly held in direct contact, comprising:
(a) walls in at least one of said members defining a circuitous channel lying along the plane of separation between said members and surrounding a zone of said joint to be sealed; and (b) a continuous strand of solid flexible sealant material in said channel adhering to both said members.

16. The seal as in claim 15, in which said channel is comprised of a groove in the face of one of said members, which groove is closed by the face of the other of said members.

17. The seal as in claim 15, in which: the solid sealant material occupies at least 98% of the interior volume of said channel.

18. A face type seal assembly comprising:
(a) a pair of abutting members in face-to-face relationship;
(b) means positively holding said members together;
(c) walls defining at least one continuous groove in the face of at least one of the abutting members, the groove forming a complete channel circuit in cooperation with the other member;

(d) means defining a single access opening through at least one of said members communicating with said groove; and (e) a solid pliable nonload-bearing seal material substantially occupying the interior of said channel and blocking said opening, said seal material adhesively sealing against the groove walls and other member and enhancing the effectiveness of said holding means.

19. The face type seal assembly as in Claim 18, in which: said material is selected from the group con-sisting of elastomeric silicones, urethanes and polyamides.

20. The face type seal as in Claim 18, in which:
said groove has a semicircular cross-section with said access opening interconnecting with the arcuate segment of said cross-section.

21. The face type seal as in Claim 18, in which:
said members are clamped together with a force sufficient to stop said sealant material from separating said members during installation.