US3017902A - Flow control - Google Patents

Description

Jan. 23, 1962 c. R. GOODYEAR FLOW CONTROL Filed Jan. 16, 1956 .INVENTOR. CHARLES R. GOODYEAR ATTOkNL-VS United States Patent 3,017,902 FLOW CONTROL Charles R. Goodyear, Detroit, Micln, assignor to Holley Carburetor Company, Van Dyke, Mich., a corporation of Michigan Filed Jan. 16, 1956, Ser. No. 559,306 2 Claims. (Cl. 13837) The present invention relates to flow control, and more particularly to means for equalizing fuel flow around a sharp corner in a continuous conduit to prevent separation of mixed fluid components.

The invention relates particularly to a system in which a mixture or an emulsion of fluid components such for example as air and liquid fuel, is caused to flow through a continuous conduit having sharp corners. Conduits of this type result for example in carburetors where the continuous passage is provided by drilling straight intersecting passages.

It has been found that the sharp corners provided by the intersection of straight passages operate to cause undesirable results. It has been observed that particularly at low flow rates, but to some extent at all flow rates, air entrained in liquid fuel tends to separate from the stream, accumulate, and enter the second passage beyond the corner to form a non-uniform mixture. At higher rates of flow the stream of fuel and air will tend to flow to the inside of the turn and form a vena contracta or minimum stream cross-section. This in effect operates as an in duced restriction.

In accordance with the present invention means are provided overcoming both of the aforementioned difficulties.

It is an object of the present invention to provide means located adjacent a sharp corner in a fluid passage operative to prevent separation between dissimilar components of a fluid mixture or emulsion and to prevent restriction of the minimum cross-sectional area of the stream of fluid.

More specifically, it is an object of the present invention to accomplish the aforementioned results by the provision in the end portion of the passage through which the mixture flows toward the corner, of a member defining therewith a restricted annular passage.

Still more specifically, it is an object of the present invention to provide a structure as defined in the preceding paragraph in which the aforesaid member is supported by a stem of reduced cross-section extending across the inner portion of said conduit.

More specifically, it is an object of the present invention to provide a fluid flow construction comprising a first passage, a second passage intersected by said first passage to which a mixture of fluids flows from said first passage, the intersection between said passages providing a common chamber, a reduced stem extending across said chamber in line with said first passage, an enlarged head carried by said stem located in the end portion of said first passage directly adjacent said chamber and defining with the end portion of said first passage a restricted annular passage. Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a schematic sectional view showing a portion of a carburetor illustrating the present invention.

FIGURE 2 is an enlarged sectional schematic view showing the details of the present invention.

FIGURES 3 and 4 are enlarged sectional schematic views showing different embodiments of the present invention.

3311902 Patented Jan. 23, 1962 In the drawings the present invention is illustrated as associated with a carburetor of conventional down draft type. The carburetor as illustrated comprises a fuel bowl 10 having a fuel inlet valve (not shown) adapted to be controlled by a float 12 to maintain the level of the fuel in the bowl as indicated at 14. The carburetor includes a venturi 16 having a throat portion 18 provided with a main fuel nozzle 20. Fuel from the bowl 10 passes through a main metering jet 22 into the main well 24 which at its upper end is connected to a fuel passage 26 through which fuel passes toward main nozzle 20.

During operation of the carburetor, when the throttle 28 is open, the flow of air induced through the venturi reduces pressure at the throat of the venturi and atmospheric pressure acting on fuel within the bowl 14 causes the liquid fuel to be discharged through the nozzle 20, where it is atomized by the high velocity flow of air therethrough.

In order to improve the mixture of fuel and air ultimately supplied to the internal combustion engine to which the carburetor is attached, air is bled into the fuel within the main well 24 through an air bleed 30 in communication with a bleed well 32 having a high speed bleed 34. With this arrangement, any pressure difference which exists between the bleed well 32 and the main well 24 will cause air to flow through the main well bleed 30 into the main well where it mixes with the fuel flowing toward the main nozzle 20. This preliminary mixture of fuel and air results in the discharge of a fuel mixture or emulsion through the main nozzle into the venturi and this preliminary mixing or emulsifying of the components greatly improves the intimacy of the ultimate mixture or emulsion as supplied to the manifold.

It has been found in the past that flow of a mixture or emulsion of fuel and air around a sharp corner in a conduit tends to cause undesirable results. In the first place, at low fuel rates the air entrained in the fuel as previously described will tend to separate from the stream, accumulate, and enter the main nozzle 20 in separated bubbles rather than as an intimate mixture with the fuel. Conversely of course, separation of air from the mixture or emulsion tends to cause the fuel to flow through the nozzle in separated discrete drops. As a result, instead of a smooth substantially uniform mixture or emulsion through the nozzle, air and fuel are discharged alternately in such a way as to make complete admixture with the air flowing through the venturi substantially impossible.

A second undesirable result is that at higher rates of flow the stream of fuel and air mixture or emulsion will tend to flow at the inside of the turn or corner and form a vena contracta or minimum stream cross-section. This operates in effect as a reduced restriction the value of which is variable in accordance with velocity of flow. This introduces into the metering system an uncontrollable variable which is extremely undesirable.

In accordance with the present invention both of the aforementioned undesirable results are substantially eliminated by the provision of means which will now be described in conjunction with FIGURE 2. As seen in this figure, the upper portion of the main well 24 constitutes a first passage intersecting the passage 26 leading to the main nozzle 20. Ordinarily, the passages 24 and 26 will be of circular cross-section, since the simplest method of producing these passages is by drilling. In any case, the two passages intersect to provide a common intersecting zone or chamber designated at 36. The passage 24 includes a cylindrical extension 37. Located generally at the intersection of the two straight passages 24 and 26 is a member indicated generally at 40 comprising a cylindrical base 41 mounted within the extension 37, and a reduced stem portion 42 located in alignment with the well or passage 24 and extending across the. chamber 36, or in other words, extending transversely of the passage 26. Carried at the free end of the reduced stem 42 is an enlarged cylindrical head portion 44 which is located centrally of the passage 24. The head 44 thus defines with the passage 24 an annular restricted passageway 46, and stem 42 causes chamber 36 to be of annular shape.

Preferably, the lower end of the head 44 is shaped conically as indicated at 48, to facilitate flow around the head.

The reduced portion 42 of the member 40 forces the channel or passage 26 to draw the fuel-air mixture or emulsion from the entire top surface of the main well or channel 24 by means of the annular space provided by the reduced upper section of the element. In addition, the increased diameter of the head 44 assures an even and homogeneous supply of fuel-air mixture or emulsion to all parts of the annular chamber above it. In this manner, the element prevents separation and crowding of the fuel-air mixture at the turn of the conduit.

In FIGURE 3 there is shown a somewhat different embodiment of the invention. Passages 50 and 52 intersect as shown, the passage 50 having an extension 54 opening to the outer surface of the body 56. Located wholly within the projection of the passage 50 and specifically within the extension thereof is a cylindrical member 58 having an inclined surface 60 which is disposed to form acute angles with the center-lines of the passages 50 and 52. As shown, the surface 60 is inclined approximately equally with respect to the two center-lines. Moreover, the surface 60 approaches the curved inner corner defined by the intersection between the two passages 50 and 52 and forms a restriction to flow at this point. This restriction to flow is located where the change in direction of flow takes place.

Referring now to FIGURE 4, there is a similar arrangement differing from that shown in FIGURE 3 only in that the member 64 is substituted for the member 58. The member 64 has an inclined passage 66, preferably of circular cross-section, extending from its lower inclined end surface 68 to the side thereof where it registers with passage 52. Again, it will be observed that the passage 66 constitutes a restriction to flow of fluid and that this restriction, to flow is located substantially in the zone or: area where change in direction of flow occurs.

The drawings and the foregoing specification constitute a description of the improved flow control in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. A carburetor body having a cylindrical bore the wall of which forms a first straight passage and a second cylindrical bore the wall of which forms a second straight passage intercepted by said first passage and into which a fuel-air mixture or emulsion flows from said first passage, means to prevent separation of the components of said mixture or emulsion upon a change in direction occasioned by passing from said first passage to said second passage, said means comprising a cylindrical stern disposed axially within said first passage and in alignment with the axis of said passage, said stern and the wall of said first bore forming an annular chamber at the interception of said passages, said chamber being in communication with the end portions of said passages, other wall means closing the end of said first passage and defining one side of said chamber and lying in a plane which is substantially tangent to said second passage, one end of said stem being fixedly secured to said other wall means, and an enlarged head on the other end of said stem and disposed in said first passage upstream of said chamber, said head defining with a wall of said first bore a restricted annular port concentric to and communicating with said chamber, said head being closely adjacent to said second passage and providing a wall portion which defines the side of said chamber opposite said other wall means, said second passage having an unrestricted outlet portion extending radially fro-m said annular chamber.

2. A carburetor body as defined in claim 1, in which the upstream end of said head is of conical form to facilitate fluid flow in said first passage through said port into said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,848,531 Lamb et al. Mar. 8, 1932. 2,111,991 Richard Mar. 22, 193.8 2,297,109 Moseley Sept. 29, 1942 2,304,609 Stokes Dec. 8, 1942v 2,311,381 Green Feb. 16, 1943 2,327,449 Parker Aug. 24,. 1943 2,341,394 Sloan Feb. 8, 1944 2,404,995 Thommen et al July 30, 1946 2,594,659 Langvand Apr. 29, 1952 2,606,573 Brobeck et al. Aug. 12, 1952 2,635,861 Olson Apr. 21, 1953 2,647,799 Kinney Aug. 4, 1953

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