CA1073493A - Carburetor mounting gasket - Google Patents
Carburetor mounting gasketInfo
- Publication number
- CA1073493A CA1073493A CA300,340A CA300340A CA1073493A CA 1073493 A CA1073493 A CA 1073493A CA 300340 A CA300340 A CA 300340A CA 1073493 A CA1073493 A CA 1073493A
- Authority
- CA
- Canada
- Prior art keywords
- gasket
- carburetor
- core
- heat
- flat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Gasket Seals (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A gasket with heat-insulating properties is provided for mounting a carburetor on an internal-combustion-engine casting. A thick core of heat-insulating resin, such as phenol-formaldehyde resin, is sandwiched between two thin cutout sheets of resilient gasket material. The core provides the heat insulation, and the gasket material provides the resilience needed to assure sealing on rough surfaces. The core is molded to shape, while the gasket material may be cut out to shape and secured to it by a separate thermo-setting resin, such as a nitrile-rubber-phenolic-resin material. The core has passage means therethrough plus bolt openings. A
first Mat surface faces the engine casting and surrounds the passage means and bolt openings. An opposite flat surface faces the carburetor. The cutout sheets can be made of nitrile rubber and asbestos fiber. Each cutout sheet has a continuous flat surface surrounding the passage means and the bolt openings.
A gasket with heat-insulating properties is provided for mounting a carburetor on an internal-combustion-engine casting. A thick core of heat-insulating resin, such as phenol-formaldehyde resin, is sandwiched between two thin cutout sheets of resilient gasket material. The core provides the heat insulation, and the gasket material provides the resilience needed to assure sealing on rough surfaces. The core is molded to shape, while the gasket material may be cut out to shape and secured to it by a separate thermo-setting resin, such as a nitrile-rubber-phenolic-resin material. The core has passage means therethrough plus bolt openings. A
first Mat surface faces the engine casting and surrounds the passage means and bolt openings. An opposite flat surface faces the carburetor. The cutout sheets can be made of nitrile rubber and asbestos fiber. Each cutout sheet has a continuous flat surface surrounding the passage means and the bolt openings.
Description
1073'~9;~
This invention relates to a novel gasket havlng significant heat-insulating properties. This application is a division of Canadian patent application Serial No. 197,601 filed April 16, 1974.
While the present gasket can be used in many environments, one which gave rise to a serious problem solved by this invention, will serve as an example. This is the gasket used in automobile engines between the carburetor and the manifold, in other words, the gasket used between the carburetor and the engine casting, to which the carburetor is mounted by bolts. A fiber gasket about 1/32nd to 1/16th inch thick or a metal inserted asbestos gasket has been used, its function being to seal, so that the fuel -- gasoline, gasoline vapor, and mixture of gasoline and air --could not escape to the atmosphere through this connection, nor could air from the atmosphere be drawn in through the connection. Such fiber gaskets were able to provide little thermal insulation. This factor was given little consideration until recently, but now it is recognized that such insulation is necessary to reduce fuel bowl temperatures, and it was found that problems were being caused by the passage of heat from the engine manifold at the engine casting to the carburetor, and that this heat transfer was affecting the operation of the carburetor by raising the temperature of the fuel bowl to an excessive temperature.
The initial attempt to solve this problem comprised using thicker gaskets, frequently about 1/4th inch thick, sometimes even thicker, in an attempt to provide some thermal insulation. Howèver, this had difficulties too in achieving accurate control of thickness and other dimensions which are necessary for good sealing performance, and for uniform distribution of compressive loads over the entire flange surface.
Other attempts combined in laminar form resin-impregnated vegetable fiberboard and elastomeric sheets.
As indicated above, it is important to provide a gasket having better heat-insulation properties. It is also important to provide a more uniform distribution of the compressive loads over the entire surface of the flange. It has also been important to provide a more accurate control of the thickness and other dimensions which contribute to sealing performance. Also, there have been problems in taking care of various three-dimensional configurations, because the gaskets have heretofore been cut from a sheet of constant thickness; while this has been a generally economical method for making gaskets, it gave no three-dimensional control or configuration at all.
Accordingly the gasket of the invention consists of a carburetor mounting gasket for interposition between a carburetor and an automobile engine casting, including in combination a thick molded core of heat-insulating resin of substantially constant thickness having passage means and bolt openings therethrough. The core includes a first flat bearing surface for facing either the engine casting or the carburetor and a second flat, non-bearing surface for facing the other of said members including a portion projecting therefrom which surrounds the passage mean~
and extensions surrounding the bolt openings. The projecting portion and the extensions all terminate in flat faces lying a common plane which is parallel to the first flat surface. A sheet of resilient gasket material is secured to the first surface by means of a thermosetting adhesive and a section of resilient gasket material is secured to the flat face of the projecting portion by means of a thermosetting adhesive.
By means of this gasket construction it has been possible to provide considerable thickness, up to a quarter of an inch and more, if desired, to effect heat insulation while minimizing the amount of gasket material in the thin sheets. But further than this, the combination offers both better heat resistance and a more uniform distribution of the compressive loads which are distributed over the entire flange surface of the member faced by the first flat surface. Still further, the thickness has been more accurately controlled than could be with conventional thick 1073~93 gasket material, while other dimensions have been controlled too by the molding process so that there is better over-all sealing performance. The resin material is substantially rigid and does not compress and all the compressing is taken care of by the thin gasket material.
One or more fins may be provided to help dissipate or deflect heat, and these can be thinner than the main core and can pro~ect out from the gasket into the air. The bolt-encircling portions are provided to nt in recesses and prevent heat from being conducted to and through the bolt.
It is possible to produce a core of any desired thickness and any configuration.
In the drawings:
Figure 1 is a top plan view of a form of carburetor gasket constructed in accordance with the instant invention;
Figure 2 is a bottom view of the gasket of Figure 1; and Figure 3 is a view in section taken along the line 3-3 of Figure 1 and shown installed in place.
Referring more specifically to the drawings, a gasket, generally shown at 30, is provided with a desired shape to fit, as shown in Figure 3, between a carburetor housing 31 and an engine manifold portion 32 of an engine casting. The gasket 30 is provided with a pair of central openings 33 and 34 which define passage means for the passage of an air/fuel mixture between the carburetor 31 and the manifold 32. The gasket 10 is also provided with a plurality of bolt openings 46 for bolts.
As shown in section in Figure 3, the gasket 30 includes a central core 40 which is molded to shape and comprises the bulk of the thiokness of the gasket. For example, in a gasket 30 having a total thickness of about 0.240 inch, the core 40 may be about . 204 to . 206 thick. This core 40 is preferably phenolformaldehyde resin filled with a mineral type of filler, such as asbestos, fuller's earth, clay, etc., or with a type of high temperature glass for especially high-temperature installations. Other ;. ~. lOq3~9;~
thermosetting resins may be used, suoh as silicone resins, alkyd resins, and poly (amideimide) resins.
A phenolic core 40 has the following typical properties;
Tensile Strength - ASTM D 638 - 7,500 psi.
Compressive Strength - ASTM D 695 - 32,000 psi.
Flexural Strength - ASTM D 790 - 15,000 psi.
Impact, I~od - ASTM D 256 - 0.26 ft. lbs. per in.
Deflection Temperature at 264 psi.-ASTM D 648 - 360F.
Modulus in tension - ASTM D 638 - 1.4 x 106 psi.
Values based on te~ts conducted at 23C.
after conditigning specimens 48 hrs. at 50 C.
Thermal Conductivity - 11.8 x 10 4 oal.
gram (15C.)/(Sec.) (cm.2) (C/cm.) - 3.42 btu (mean)/(hr.) (ft. ) ( F/inch) Water Absorption - ASTM D 570 - 0.35~
The upper temperature limit of the phenolic core 40 is about 500F., as compared with a limit of about 300F. for fiberboard. The core 40 includes a first flat bearing surface 41 which faces either the carburetor 31 or the engine casting 32. In the preferred embodiment the flat bearing surface secured to this first surface 41 is a thin sheet or skin 50 of resilient gasket material. As is apparent from Figure 2, the first nat bearing surface 41 defines a continuous extended surface area which facilitates a uniform distribution of the compressive load over the flange surface 32 of the engine casting.
The core 40 also includes a second flat non-bearing surface 54 opposite the first surface 41 for facing the carburetor 31. A thick portion 42 projects from the second surface 54 and surrounds the openings 33 and 34 which define the passage means. At each bolt opening 46 the core 40 i9 thickened to provide a projection or extension 47 which is 1073~93 cylindrical in shape. The projecting portion 42 and the extensions 47 terminate in flat faces which all lie in a common plane which is parallel to the first flat surface as shown in Figure 3. A sheet or skin 51 of resilient gasket material are secured to the flat face of the thickened portion 42.
The gasket material may be composed of resilient nitrile rubber and asbestos fiber, produced by the beater addition process so as to be highly uniform, and then formed into sheets and blanked out to shape. This composition has both excellent heat resistance and excellent resistance to lO petroleum fuels, lubricants, water, and other liquids encountered. It can be used at temperatures up to 500 F.
Typical material specifications are:
Compressibility 5000 psi. load, % 15-25 Recovery, minimum % 40 Tensile Strength Longitudinal, minimum psi. 3,000 Transverse, minimum psi. 2,000 Fluid Immersion ASTM Oil No. 3-5 hours at 300F.
Compressibility, maximum ~ 30 Loss in Tensile Strength, maximum % 35 Thickness IncreaQe, ~ 5-15 ASTM Ref. Fuel B--5 hours at 70-80F.
Weight Increase, maximum ~ 30 Thickness Increase, % 5-15 Test procedures are according to ASTM F104. Other typical kinds of materials which may be used include compositions of styrene elastomer and asbestos, polychloroprene elastomer and asbestos, and blends of the named polymers and asbestos.
; The gasket material should have sufficient heat resistance to be able to stand the temperature environment, but are not relied upon primarily for insulation but for their ability to seal and to provide 1073~193 sufficient resilience. Sinoe they are thin, they do not transmit their resilience to changes in shape elsewhere to any excessive degree and, therefore, can be well relied upon to give accurate thicknesses and not to affect the accuracy of thickness of the composite gasket 10. Similarly, the combination of the core 20 with the gasket material uniformly distributes the compressive loads over the entire flange surface of the engine casting instead of allowing some portion to give more than others to a really substantial degree, yet there is enough conformability to enable the gasket 30 to take care of various environments and to accommodate the roughness of the surfaces between which the gasket 10 is being installed.
The member 40 also has a projection 45 extending outside the gasketing area and much thinner than the body 41. This portion 45 serves as a heat-dissipating and deflecting fin, to radiate some of the heat into the environment.
~ o those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.
~', iL ,~ 6 -
This invention relates to a novel gasket havlng significant heat-insulating properties. This application is a division of Canadian patent application Serial No. 197,601 filed April 16, 1974.
While the present gasket can be used in many environments, one which gave rise to a serious problem solved by this invention, will serve as an example. This is the gasket used in automobile engines between the carburetor and the manifold, in other words, the gasket used between the carburetor and the engine casting, to which the carburetor is mounted by bolts. A fiber gasket about 1/32nd to 1/16th inch thick or a metal inserted asbestos gasket has been used, its function being to seal, so that the fuel -- gasoline, gasoline vapor, and mixture of gasoline and air --could not escape to the atmosphere through this connection, nor could air from the atmosphere be drawn in through the connection. Such fiber gaskets were able to provide little thermal insulation. This factor was given little consideration until recently, but now it is recognized that such insulation is necessary to reduce fuel bowl temperatures, and it was found that problems were being caused by the passage of heat from the engine manifold at the engine casting to the carburetor, and that this heat transfer was affecting the operation of the carburetor by raising the temperature of the fuel bowl to an excessive temperature.
The initial attempt to solve this problem comprised using thicker gaskets, frequently about 1/4th inch thick, sometimes even thicker, in an attempt to provide some thermal insulation. Howèver, this had difficulties too in achieving accurate control of thickness and other dimensions which are necessary for good sealing performance, and for uniform distribution of compressive loads over the entire flange surface.
Other attempts combined in laminar form resin-impregnated vegetable fiberboard and elastomeric sheets.
As indicated above, it is important to provide a gasket having better heat-insulation properties. It is also important to provide a more uniform distribution of the compressive loads over the entire surface of the flange. It has also been important to provide a more accurate control of the thickness and other dimensions which contribute to sealing performance. Also, there have been problems in taking care of various three-dimensional configurations, because the gaskets have heretofore been cut from a sheet of constant thickness; while this has been a generally economical method for making gaskets, it gave no three-dimensional control or configuration at all.
Accordingly the gasket of the invention consists of a carburetor mounting gasket for interposition between a carburetor and an automobile engine casting, including in combination a thick molded core of heat-insulating resin of substantially constant thickness having passage means and bolt openings therethrough. The core includes a first flat bearing surface for facing either the engine casting or the carburetor and a second flat, non-bearing surface for facing the other of said members including a portion projecting therefrom which surrounds the passage mean~
and extensions surrounding the bolt openings. The projecting portion and the extensions all terminate in flat faces lying a common plane which is parallel to the first flat surface. A sheet of resilient gasket material is secured to the first surface by means of a thermosetting adhesive and a section of resilient gasket material is secured to the flat face of the projecting portion by means of a thermosetting adhesive.
By means of this gasket construction it has been possible to provide considerable thickness, up to a quarter of an inch and more, if desired, to effect heat insulation while minimizing the amount of gasket material in the thin sheets. But further than this, the combination offers both better heat resistance and a more uniform distribution of the compressive loads which are distributed over the entire flange surface of the member faced by the first flat surface. Still further, the thickness has been more accurately controlled than could be with conventional thick 1073~93 gasket material, while other dimensions have been controlled too by the molding process so that there is better over-all sealing performance. The resin material is substantially rigid and does not compress and all the compressing is taken care of by the thin gasket material.
One or more fins may be provided to help dissipate or deflect heat, and these can be thinner than the main core and can pro~ect out from the gasket into the air. The bolt-encircling portions are provided to nt in recesses and prevent heat from being conducted to and through the bolt.
It is possible to produce a core of any desired thickness and any configuration.
In the drawings:
Figure 1 is a top plan view of a form of carburetor gasket constructed in accordance with the instant invention;
Figure 2 is a bottom view of the gasket of Figure 1; and Figure 3 is a view in section taken along the line 3-3 of Figure 1 and shown installed in place.
Referring more specifically to the drawings, a gasket, generally shown at 30, is provided with a desired shape to fit, as shown in Figure 3, between a carburetor housing 31 and an engine manifold portion 32 of an engine casting. The gasket 30 is provided with a pair of central openings 33 and 34 which define passage means for the passage of an air/fuel mixture between the carburetor 31 and the manifold 32. The gasket 10 is also provided with a plurality of bolt openings 46 for bolts.
As shown in section in Figure 3, the gasket 30 includes a central core 40 which is molded to shape and comprises the bulk of the thiokness of the gasket. For example, in a gasket 30 having a total thickness of about 0.240 inch, the core 40 may be about . 204 to . 206 thick. This core 40 is preferably phenolformaldehyde resin filled with a mineral type of filler, such as asbestos, fuller's earth, clay, etc., or with a type of high temperature glass for especially high-temperature installations. Other ;. ~. lOq3~9;~
thermosetting resins may be used, suoh as silicone resins, alkyd resins, and poly (amideimide) resins.
A phenolic core 40 has the following typical properties;
Tensile Strength - ASTM D 638 - 7,500 psi.
Compressive Strength - ASTM D 695 - 32,000 psi.
Flexural Strength - ASTM D 790 - 15,000 psi.
Impact, I~od - ASTM D 256 - 0.26 ft. lbs. per in.
Deflection Temperature at 264 psi.-ASTM D 648 - 360F.
Modulus in tension - ASTM D 638 - 1.4 x 106 psi.
Values based on te~ts conducted at 23C.
after conditigning specimens 48 hrs. at 50 C.
Thermal Conductivity - 11.8 x 10 4 oal.
gram (15C.)/(Sec.) (cm.2) (C/cm.) - 3.42 btu (mean)/(hr.) (ft. ) ( F/inch) Water Absorption - ASTM D 570 - 0.35~
The upper temperature limit of the phenolic core 40 is about 500F., as compared with a limit of about 300F. for fiberboard. The core 40 includes a first flat bearing surface 41 which faces either the carburetor 31 or the engine casting 32. In the preferred embodiment the flat bearing surface secured to this first surface 41 is a thin sheet or skin 50 of resilient gasket material. As is apparent from Figure 2, the first nat bearing surface 41 defines a continuous extended surface area which facilitates a uniform distribution of the compressive load over the flange surface 32 of the engine casting.
The core 40 also includes a second flat non-bearing surface 54 opposite the first surface 41 for facing the carburetor 31. A thick portion 42 projects from the second surface 54 and surrounds the openings 33 and 34 which define the passage means. At each bolt opening 46 the core 40 i9 thickened to provide a projection or extension 47 which is 1073~93 cylindrical in shape. The projecting portion 42 and the extensions 47 terminate in flat faces which all lie in a common plane which is parallel to the first flat surface as shown in Figure 3. A sheet or skin 51 of resilient gasket material are secured to the flat face of the thickened portion 42.
The gasket material may be composed of resilient nitrile rubber and asbestos fiber, produced by the beater addition process so as to be highly uniform, and then formed into sheets and blanked out to shape. This composition has both excellent heat resistance and excellent resistance to lO petroleum fuels, lubricants, water, and other liquids encountered. It can be used at temperatures up to 500 F.
Typical material specifications are:
Compressibility 5000 psi. load, % 15-25 Recovery, minimum % 40 Tensile Strength Longitudinal, minimum psi. 3,000 Transverse, minimum psi. 2,000 Fluid Immersion ASTM Oil No. 3-5 hours at 300F.
Compressibility, maximum ~ 30 Loss in Tensile Strength, maximum % 35 Thickness IncreaQe, ~ 5-15 ASTM Ref. Fuel B--5 hours at 70-80F.
Weight Increase, maximum ~ 30 Thickness Increase, % 5-15 Test procedures are according to ASTM F104. Other typical kinds of materials which may be used include compositions of styrene elastomer and asbestos, polychloroprene elastomer and asbestos, and blends of the named polymers and asbestos.
; The gasket material should have sufficient heat resistance to be able to stand the temperature environment, but are not relied upon primarily for insulation but for their ability to seal and to provide 1073~193 sufficient resilience. Sinoe they are thin, they do not transmit their resilience to changes in shape elsewhere to any excessive degree and, therefore, can be well relied upon to give accurate thicknesses and not to affect the accuracy of thickness of the composite gasket 10. Similarly, the combination of the core 20 with the gasket material uniformly distributes the compressive loads over the entire flange surface of the engine casting instead of allowing some portion to give more than others to a really substantial degree, yet there is enough conformability to enable the gasket 30 to take care of various environments and to accommodate the roughness of the surfaces between which the gasket 10 is being installed.
The member 40 also has a projection 45 extending outside the gasketing area and much thinner than the body 41. This portion 45 serves as a heat-dissipating and deflecting fin, to radiate some of the heat into the environment.
~ o those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.
~', iL ,~ 6 -
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A carburetor mounting gasket for interposition between a carburetor and an automobile engine casting comprising: a thick molded core of heat-insulating resin of substantially constant thickness having passage means therethrough and bolt openings; said core including a first flat bearing surface for facing one of said engine casting and said carburetor and a second flat, non-bearing surface opposite said first surface for facing the other of said engine casting and said carburetor;
said second surface including a portion projecting therefrom which surrounds said passage means and extensions surrounding said bolt openings, said projecting portion and said extensions terminating in flat faces lying in a common plane which is parallel to said first flat surface; a first sheet of resilient gasket material secured to said first surface and a second sheet of resilient gasket material secured to the flat face of said projecting portion, said gasket material being secured by means of a thermosetting adhesive.
said second surface including a portion projecting therefrom which surrounds said passage means and extensions surrounding said bolt openings, said projecting portion and said extensions terminating in flat faces lying in a common plane which is parallel to said first flat surface; a first sheet of resilient gasket material secured to said first surface and a second sheet of resilient gasket material secured to the flat face of said projecting portion, said gasket material being secured by means of a thermosetting adhesive.
2. A carburetor gasket as set forth in claim 1 wherein said gasket material is comprised of an elastomer and asbestos.
3. A carburetor mounting gasket as set forth in claim 2 wherein each of said two sheets of resilient material includes the following specifications:
4. A carburetor mounting gasket as described in claim 2 wherein said core includes at least one thinner non-load bearing heat-deflecting portion of said heat-insulating resin.
5. A carburetor mounting gasket as described in claim 2 or 3 wherein said core is made from filled phenol-formaldehyde resin.
6. A carburetor mounting gasket as described in claim 2 wherein said sheets of resilient material are made from a blend of nitrile rubber and asbestos fiber.
7. A carburetor gasket as described in claim 6 wherein said thermosetting adhesive is a blend of phenol-formaldehyde resin and nitrile rubber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA300,340A CA1073493A (en) | 1973-05-08 | 1978-04-03 | Carburetor mounting gasket |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US35829373A | 1973-05-08 | 1973-05-08 | |
| CA197,601A CA1034616A (en) | 1973-05-08 | 1974-04-16 | Gasket with heat insulating properties |
| CA300,340A CA1073493A (en) | 1973-05-08 | 1978-04-03 | Carburetor mounting gasket |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1073493A true CA1073493A (en) | 1980-03-11 |
Family
ID=27163426
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA300,340A Expired CA1073493A (en) | 1973-05-08 | 1978-04-03 | Carburetor mounting gasket |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1073493A (en) |
-
1978
- 1978-04-03 CA CA300,340A patent/CA1073493A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |