CA1036444A - Carburetor inlet valve seat - Google Patents
Carburetor inlet valve seatInfo
- Publication number
- CA1036444A CA1036444A CA260,454A CA260454A CA1036444A CA 1036444 A CA1036444 A CA 1036444A CA 260454 A CA260454 A CA 260454A CA 1036444 A CA1036444 A CA 1036444A
- Authority
- CA
- Canada
- Prior art keywords
- bore
- insert
- end wall
- valve
- drilled
- 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
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M5/00—Float-controlled apparatus for maintaining a constant fuel level
- F02M5/12—Other details, e.g. floats, valves, setting devices or tools
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Lift Valve (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
A combination valve seat and seal for the inlet passage of a carburetor, the purpose being to provide a resilient seat for a metal inlet valve and also to seal the portion of the housing around the seat so that any accidental or inherent porosity in the carburetor casting will not allow fuel to leak through the inlet valve when it is in closed posi-tion. The construction of the insert is such that it seals against the incoming fuel pressure to pre-vent pressure dislodgement of the seal.
A combination valve seat and seal for the inlet passage of a carburetor, the purpose being to provide a resilient seat for a metal inlet valve and also to seal the portion of the housing around the seat so that any accidental or inherent porosity in the carburetor casting will not allow fuel to leak through the inlet valve when it is in closed posi-tion. The construction of the insert is such that it seals against the incoming fuel pressure to pre-vent pressure dislodgement of the seal.
Description
11)36444 This invention relates to an improvement in a Carburetor Inlet Valve Seat and more paxticularly to the material and design of a valve seat which co-operates with an inlet valve to control the amount of fuel which can reach a control chamber in a carburetor from the ~uel source.
It will be appreciated that all carburetors must receive a supply of fuel from a fuel tank. Some-times this fuel is ~urnished to the carburetor by a gravity feed from a tank. In other instances, it is furnished by a pump which moves the fuel from a tank to the carburetor. In either case there is generally a fuel head at the carburetor which is controlled in its flow to the interior of the carburetor by an inlet valve.
It has been desirable in valves of this kind to avoid a metal-to-metal contact. In a larger fl~at carburetor illustrated in a U. S. patent to Tuckey 3,265,050 (Aug. 9, 1966), there is shown a resilient tip on the inlet valve which cooperates with a valve seat in a threaded insert. In other disclosure3 as illustrated in the U. S. patents to Schneider 3,361,120 (Jan. 2, 1968) and 3,690,304 (Sept. 12, 1972), there is shown a metal valve seat insert carrying a plastic valve seat which c~operates with a metal inlet valve.
10;~6~44 Recent dsvelopments in the past few years relative to smaller engines and more limited space resulting particularly from chain saw design, the space available for the inlet valve has been greatly reduced. It has been necessary) therefore, to drill the valve seat directly into the carburetor body as illustrated, for example, in a U. S. patent to Tuckey 3,758,084 (Sept. 11, 1973). The valve seat has thus been a metallic valve seat formed by a portion of the carburetor housing; and even when a resilient tip on the valve was utilized to prevent wear, there were prob-lems with the design due in part to the inadvertent porosity of the castings which would cause leaks. The machining of the seat in the casting very often involved three separate operations to get a proper finish and, yet, in instances where porosity was revealed by these machining operations, the casting would have to be com-pletely rejected. One attempt to solve this problem is illustrated in a U. S. patent to Donovan 3,791,632 (Feb. 12, 1974).
The present invention is intended to be an improvement on the previous inlet valve designs which solves the problems of the casting porosity, and it ~0364~L
eliminates the expensive machining as well as reduces the cost of the entire assembly. In addition, the present system eliminates the need for a plastic tip on the inlet valve. Thus, the present invention eli-minates machining, reduces the cost of the inlet valve,and solves the problem of the sealing of the car~uretor housing in case of unwanted porosity.
Other objects and features of the invention relating to details of construction and operation will be apparent in the following description and claims in which the principles of operation are set forth to-gether with the best mode presently contemplated for the practice of the invention.
DRAWI~GS accompany the disclosure and the various views thereof may be briefly described as:
FIGURE l, a sectional view of a carburetor in which the invention may be used.
EIGURE 2, an enlarged view of the valve seat insert prior to assembly.
1~6~4 With reference to the drawings, in FIGURE 1, a sectional view of a carburetor is shown. This car-buretor is described in detail in U. S. Patsnt No.
3,758,084, above referenced. It consists basically of a carburetor body 20 having a top plate 2~ which formsO in connection with the body, a pumping chamber 24 which furnishes fuel under pressure to a fuel inlet chamber or port 26. A venturi or mixing chamber 28 i8 provided in the usual mannex and at the bottom of the carburetor housing is a flexible diaphragm 30 which contaols a spring-backed lever 32 which acts upon an inlet valve 40 which moves axially in a drilled bore 42 in the body. The valve 40 is fluted to allow the passage of fuel around it and it has a tipped portion 44 which cooperates with the valve seat to be described.
The valve seat 50 is shown in an enlarged view ~FIGURE 2) in unassembled condition, and it is shown assembled in FIGURE 1 in the drilled bore 42.
This valve seat is preferably formed of fuel resistant synthetic rubber material or its equivalent. The insert i~ a cylindrical element which has a stepped ~ 3~4~9~
outer diameter, the smaller diamet r 52 being at the bottom of the unit and the larger diameter 54 being at the top, ~here being tapered portions 56 and 58 at each end of the enlarged portion. The insert has a central passage 60 extending from end to end and directly adjacent the upper periphery of the passage 60 is an annular rim 62.
When the insert 50 is installed in the drilled bore 42, it i5 forced upwar~ly into the bore which has a diameter substantially equal to the small-er diameter portion 52. This cause~ a compression displacement Qf the larger portion 54 so that it seals against the walls of the drilled bore 42 and also has a snug fit in relation thereto. Also during the assembly the annular portion 62 is forced up against an end wall 64 of the drilled bore 42 where it surrounds a short inlet passage 66 leading from the inlet port 26 to the drilled bore 42. Thus, there will be a pressure seal directly around the bottom of the short passage 66 which will prevent fuel from bleeding and exerting a dislodging pressure over the entire top surface of the insert 50. In the operation, of course, the inlet valve 40 will be regulated in its position by the control diaphragm 30 in the usual way and the tapered point of the valve will cooperate with the lower end of the center pas~age 60 which serves as a valve seat 70.
Thus, it will be seen that the molded in-sert 60 can be produced very inexpensively in large quantities and easily installed in the top of the drilled bore 42 against the end wall 64. This avoids expensive machining and will seal porosity that might exist which would allow fuel to pass from the port 26 to the drilled passage 42 below the insert. It also seals agai~st the end wall to prevent pressure dislodge-ment and it inherently provides the necessary slightly resilient valve seat which cooperates with the valve tip 44.
It will be appreciated that all carburetors must receive a supply of fuel from a fuel tank. Some-times this fuel is ~urnished to the carburetor by a gravity feed from a tank. In other instances, it is furnished by a pump which moves the fuel from a tank to the carburetor. In either case there is generally a fuel head at the carburetor which is controlled in its flow to the interior of the carburetor by an inlet valve.
It has been desirable in valves of this kind to avoid a metal-to-metal contact. In a larger fl~at carburetor illustrated in a U. S. patent to Tuckey 3,265,050 (Aug. 9, 1966), there is shown a resilient tip on the inlet valve which cooperates with a valve seat in a threaded insert. In other disclosure3 as illustrated in the U. S. patents to Schneider 3,361,120 (Jan. 2, 1968) and 3,690,304 (Sept. 12, 1972), there is shown a metal valve seat insert carrying a plastic valve seat which c~operates with a metal inlet valve.
10;~6~44 Recent dsvelopments in the past few years relative to smaller engines and more limited space resulting particularly from chain saw design, the space available for the inlet valve has been greatly reduced. It has been necessary) therefore, to drill the valve seat directly into the carburetor body as illustrated, for example, in a U. S. patent to Tuckey 3,758,084 (Sept. 11, 1973). The valve seat has thus been a metallic valve seat formed by a portion of the carburetor housing; and even when a resilient tip on the valve was utilized to prevent wear, there were prob-lems with the design due in part to the inadvertent porosity of the castings which would cause leaks. The machining of the seat in the casting very often involved three separate operations to get a proper finish and, yet, in instances where porosity was revealed by these machining operations, the casting would have to be com-pletely rejected. One attempt to solve this problem is illustrated in a U. S. patent to Donovan 3,791,632 (Feb. 12, 1974).
The present invention is intended to be an improvement on the previous inlet valve designs which solves the problems of the casting porosity, and it ~0364~L
eliminates the expensive machining as well as reduces the cost of the entire assembly. In addition, the present system eliminates the need for a plastic tip on the inlet valve. Thus, the present invention eli-minates machining, reduces the cost of the inlet valve,and solves the problem of the sealing of the car~uretor housing in case of unwanted porosity.
Other objects and features of the invention relating to details of construction and operation will be apparent in the following description and claims in which the principles of operation are set forth to-gether with the best mode presently contemplated for the practice of the invention.
DRAWI~GS accompany the disclosure and the various views thereof may be briefly described as:
FIGURE l, a sectional view of a carburetor in which the invention may be used.
EIGURE 2, an enlarged view of the valve seat insert prior to assembly.
1~6~4 With reference to the drawings, in FIGURE 1, a sectional view of a carburetor is shown. This car-buretor is described in detail in U. S. Patsnt No.
3,758,084, above referenced. It consists basically of a carburetor body 20 having a top plate 2~ which formsO in connection with the body, a pumping chamber 24 which furnishes fuel under pressure to a fuel inlet chamber or port 26. A venturi or mixing chamber 28 i8 provided in the usual mannex and at the bottom of the carburetor housing is a flexible diaphragm 30 which contaols a spring-backed lever 32 which acts upon an inlet valve 40 which moves axially in a drilled bore 42 in the body. The valve 40 is fluted to allow the passage of fuel around it and it has a tipped portion 44 which cooperates with the valve seat to be described.
The valve seat 50 is shown in an enlarged view ~FIGURE 2) in unassembled condition, and it is shown assembled in FIGURE 1 in the drilled bore 42.
This valve seat is preferably formed of fuel resistant synthetic rubber material or its equivalent. The insert i~ a cylindrical element which has a stepped ~ 3~4~9~
outer diameter, the smaller diamet r 52 being at the bottom of the unit and the larger diameter 54 being at the top, ~here being tapered portions 56 and 58 at each end of the enlarged portion. The insert has a central passage 60 extending from end to end and directly adjacent the upper periphery of the passage 60 is an annular rim 62.
When the insert 50 is installed in the drilled bore 42, it i5 forced upwar~ly into the bore which has a diameter substantially equal to the small-er diameter portion 52. This cause~ a compression displacement Qf the larger portion 54 so that it seals against the walls of the drilled bore 42 and also has a snug fit in relation thereto. Also during the assembly the annular portion 62 is forced up against an end wall 64 of the drilled bore 42 where it surrounds a short inlet passage 66 leading from the inlet port 26 to the drilled bore 42. Thus, there will be a pressure seal directly around the bottom of the short passage 66 which will prevent fuel from bleeding and exerting a dislodging pressure over the entire top surface of the insert 50. In the operation, of course, the inlet valve 40 will be regulated in its position by the control diaphragm 30 in the usual way and the tapered point of the valve will cooperate with the lower end of the center pas~age 60 which serves as a valve seat 70.
Thus, it will be seen that the molded in-sert 60 can be produced very inexpensively in large quantities and easily installed in the top of the drilled bore 42 against the end wall 64. This avoids expensive machining and will seal porosity that might exist which would allow fuel to pass from the port 26 to the drilled passage 42 below the insert. It also seals agai~st the end wall to prevent pressure dislodge-ment and it inherently provides the necessary slightly resilient valve seat which cooperates with the valve tip 44.
Claims
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1.
A carburetor assembly having a movable inlet control valve for controlling the flow of fuel to a control chamber which comprises a carburetor body hav-ing a fuel control chamber and a fuel inlet port, a valve bore drilled in said body leading from said fuel control chamber toward said port terminating in an end wall substantially transverse of the axis of said bore, an inlet passage formed in said body having a diameter substantially smaller than said drilled valve bore and connecting said bore and said fuel inlet port, a valve seat insert in said drilled valve bore comprising a cylindrical insert of dense compressible material such as a synthetic rubber forced into said bore having one end in sealing contact with said end wall and side walls in sealing contact with the walls of said drilled valve bore adjacent said end wall, and having a central pass-age in communication with said inlet passage, and an inlet control valve slidable in said drilled bore hav-ing a tip to enter and close the central passage in said insert, said cylindrical insert having a portion of its outer wall larger than the remainder of its outer wall and larger than the diameter of said drilled valve bore at the vicinity of said end wall whereby said insert will be compressed in assembly to seat securely in said bore and seal the walls of said bore adjacent the end wall, the end of said insert in contact with said end end wall having a relative-ly narrow, annular projection to lie in contact with said end wall directly adjacent the periphery of said inlet passage to seal against said end wall and block dislodging pressure from the entire end surface of said insert.
1.
A carburetor assembly having a movable inlet control valve for controlling the flow of fuel to a control chamber which comprises a carburetor body hav-ing a fuel control chamber and a fuel inlet port, a valve bore drilled in said body leading from said fuel control chamber toward said port terminating in an end wall substantially transverse of the axis of said bore, an inlet passage formed in said body having a diameter substantially smaller than said drilled valve bore and connecting said bore and said fuel inlet port, a valve seat insert in said drilled valve bore comprising a cylindrical insert of dense compressible material such as a synthetic rubber forced into said bore having one end in sealing contact with said end wall and side walls in sealing contact with the walls of said drilled valve bore adjacent said end wall, and having a central pass-age in communication with said inlet passage, and an inlet control valve slidable in said drilled bore hav-ing a tip to enter and close the central passage in said insert, said cylindrical insert having a portion of its outer wall larger than the remainder of its outer wall and larger than the diameter of said drilled valve bore at the vicinity of said end wall whereby said insert will be compressed in assembly to seat securely in said bore and seal the walls of said bore adjacent the end wall, the end of said insert in contact with said end end wall having a relative-ly narrow, annular projection to lie in contact with said end wall directly adjacent the periphery of said inlet passage to seal against said end wall and block dislodging pressure from the entire end surface of said insert.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US60999175A | 1975-09-03 | 1975-09-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1036444A true CA1036444A (en) | 1978-08-15 |
Family
ID=24443170
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA260,454A Expired CA1036444A (en) | 1975-09-03 | 1976-09-02 | Carburetor inlet valve seat |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5237630A (en) |
| CA (1) | CA1036444A (en) |
| DE (1) | DE2638482A1 (en) |
| SE (1) | SE7609693L (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8973905B2 (en) | 2012-09-27 | 2015-03-10 | Kohler Co. | Venturi insert for a carburetor, and carburetor, system and apparatus incorporating the same |
-
1976
- 1976-08-25 JP JP51100738A patent/JPS5237630A/en active Granted
- 1976-08-26 DE DE19762638482 patent/DE2638482A1/en active Pending
- 1976-09-02 CA CA260,454A patent/CA1036444A/en not_active Expired
- 1976-09-02 SE SE7609693A patent/SE7609693L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5439536B2 (en) | 1979-11-28 |
| DE2638482A1 (en) | 1977-03-10 |
| JPS5237630A (en) | 1977-03-23 |
| SE7609693L (en) | 1977-03-04 |
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