US 2313773 A
Description (OCR text may contain errors)
March '16, 1943. D. SAMIRAN 2,313,773
AIR ELIMINATOR Filed May 16, 1940 3 Sheets-Sheet l 3i UPPLY INLET r0 PUMP 70 l/VlET 0f CHHBUHETOI? 0/? FUEL MUECTOR m I as T' 3. 1* 65w =3 0412/0 SAM/Q4252 7 as. W60 7 BY a MM 1? TTORNEYS.
March 16, 1943. D. SAMIRAN AIR ELIMINATOR Filed May 16. 1940 5 Sheets-Sheet 2 v /l/lllll/f/Ifllfl l 7/ lrlavllfflll INVENTOR.
DAV/0 iv/v/leA/v ATTORNEYS.
March 16, 1943. SAMIRAN 2,313,773
AIR ELIMINATOR Filed May 16, 1940 3 Sheets-Sheet 3 v JNVENTOR. 04 W0 (SAM/RflN ATTORNEYS.
Patented Mar. 16, 1943 UNITED STATES PATENT OFFICE amnmnm-roa David Samiran, l 'airlleld, Ohio Application May 16, 1940, Serial No. 335,646 13 Claims. (01. lav-ea)- (Granted under the act of March 3, 1883, as
amended April 30, 1928; 370 0. G. 757) a The invention described herein may be manufactured and used by or-for the Government for overnmental purposes, without the payment to me of any royalty thereon.
, The present invention relates in general to fuel feeding systems, such as employed in connection with airplanes, automobiles and Diesel engines. More particularly the present invention is directed to certain novel apparatus for use in conjunction with such systems.
The presence of air, fumes and vapor has long been a serious problem infuel systems for internal combustion engines of airplanes or automobiles, and also Diesel engines, wherein such air, fumes or vapor enter, or is created n the fuel supply conduits and is subsequently fed into the carburetor or injector apparatus. This condition obviously is of more serious nature in connection with engines of airplanes, such as when the airplane approaches relatively high altitudes, under which condition the fuel in the system vaporizes to a much higher degree than at lower altitudes. As is well known, at certain altitudes the fuel in effect boils, thereby developing bubbles and air and vapor pockets in the fuel being fed through the system to the carburetor or injector apparatus. This condition results in varying the ratio of the fuel mixture,
producing a lean mixture which causes faltering of the engine, with consequent reduction in speed and lack of power. Suchefiects upon the engine of an airplane are extremely serious and render the plane more difficult to maneuver and may result in serious mishaps. Moreover at high altitudes, in addition to the conditions above mentioned, the fuel in the supply system, in effect, becomes expanded or stretched due to the tendency to continuously supply an adequate amount of fuel to the carburetor or injector apparatus, thus causing partial starving of the carburetor or injector, and thereby varying the ratio of fuel mixture entering the carburetor or injector apparatus. Such conditions also cause a reduction in speed and lack of power, with the attendant dangersabove indicated. a
As is well known, in airplane constructions at the present time, there is employed a plurality of fuel supply tanks and when one of the tanks is exhausted, another tank of fuel is connected into the fuel supply system. During this interval of switch-over there is a possibility of air and vapor getting into the system, which also produces the difllculties above mentioned.
While the present invention is adapted for use in connection with internal combustion engines, such as in airplanes and automobiles, as well as Diesel engines, the following explanation of the construction and operation of the apparatus constituting'this invention will be treated primarily in connection with problems resulting from such conditions ofthe fuel systems of airplanes.
The present application is a continuation in part of my copending application Serial No. 261,542, filed March 13, 1939, which is directed broadly to a fuel supply system.
One of the objects of this invention resides in the provision of novel apparatus adapted for constantly eliminating air, fumes and vapor from a fuel supply system, prior to the supplying of fuel to the carburetor or injector apparatus and also capable of functioning at various altitudes.
A further object is to provide a novel form of apparatus of the character indicated for constantly eliminating air, fumes and vapor from the fuel system, together with a vent conduit for carrying off said air, fumes and vapor for discharge thereof into the upper part of a fuel supply tank above the fuel therein, the space above the fuel in turning being vented to atmosphere.
Still another object is to provide a novel device of the character indicated, which is so constructed as to provide a small auxiliary reserve supply of fuel for the carburetor or injector apparatus, adapted to be utilized for maintaining operation of the engine for a short period of time after the main fuel source is exhausted during which time air is being pumped into the system, or when, for various reasons, the pump is unable to supply the requisite quantity of fuel to the carburetor or injector apparatus of the engine.
A still further object of this invention resides in the provision of a novel device of the character indicated having associated therewith and actuated responsively thereto a pressure actuated switch for controlling other apparatus associated with the fuel supply system.
Other objects and advantages of this invention will be apparent from the following description, taken in connection with the accompanying drawings in which- Figure l is a diagrammatic, fragmentary representation of certain elements of a fuel supply system, including the apparatus constituting the present invention;
Figure 2 is an enlarged cross sectional view of one embodiment of my novel air-vapor eliminator and pressure-responsive switch device;
, Figure 2A is an enlarged sectional view of the upper and lower ends. of the float and valve structure of Figure 2 showing the parts in an initial position;
Figure 2B is a similar view of the upper portion of Figure 2A showing the float valve in an intermediate position; 1
Figure 2C is a similar view showing the float valve in final closed position as in Figure 2, the details of Figure 2 being more clearly shown in this figure;
Figure 3 is an enlarged cross sectional view of another embodiment of an air-vapor eliminator device;
Figure 3A is an enlarged sectional view of the upper portion of Figure 3 showing the float valve thereof in an intermediate position;
Figure 3B is a similar view showing the float valve in its final closed position;
Figure 4 is a cross sectional view of a further embodiment of air-vapor eliminator, especially adapted for use in connection with high pressure fuel systems, such as in connection with supercharged engines, and
Figure 5 is a sectional view through another modified form of my invention showing an enlarged reservoir portion for a reserve supply of fuel so constructed that most of the reserve supply is maintained-therein even when the eliminator is tipped a considerable degree, as when taking oil" in an airplane.
Referring now to Figure l of the drawings, I have shown a fuel supply or storage tank indicated at 30, having a supply outlet 3|, adapted for connection to a fuel pump (not shown) the upper'end of the tank being provided with a down-turned conduit 32 constituting the usual air vent. The novel air-vapor eliminator unit is indicated generally at 33, and has connected thereto a fuel supply conduit 34, adapted to be connected to the pump, and also a fuel discharge conduit 35 adapted to be connected to a carburetor or fuel injector apparatus (not shown).
The upper endof the air-vapor eliminator 33 is connected by a conduit 38 to the top of the fuel storage tank 30 and serves to constantly convey air, fumes, and vapor from the fuel system, for discharge into the top of the storage tank, and thereby precludes passage of any appreciable amount of air, fumes or vapor into the carburetor or injector. apparatus. This arrangement thereby permits the escape of the air, through vent pipe 32 of the storage tank, and any of the vapors that again become condensed into liquid form within the tank are thereby salvaged.
It is to be understood that Figure l is merely a diagrammatic illustration, and any practical number of fuel supply tanks may be employed in connection with the fuel supply system, such as used in connection with airplanes.
The air-vapor eliminator as represented in Figures l and 2, of the drawings is of the type having directly mounted on top thereof a pressureresponsive switch, indicated generally at 49, which, it may be understood, may be employed for controlling an electrical circuit for other apparatus used in conjunction with a fuel supply system. Subject to certain limitations, as pointed out in my copending application above referred to, the pressure-responsive switch need not necessarily be made a part of the air-vapor eliminator, but may be a separate unit. An aireliminator of this type is preferably used in connection with low pressure fuel systems utilizing either a carburetor or injector apparatus.
The air-vapor eliminator 33 is composed of a cup-shaped housing 44, surmounted at its open end by a cover plate 45. The cover plate 45 also serves as a supporting base for the pressure responsive switch indicated at 40, and includes provision for a pipe fitting attachment. The cupshaped housing 44 is provided at its lowermost extremity with a horizontal inlet 46, adapted to be connected to conduit 34 from the pump, a vertical outlet 41 adapted to be connected by conduit 35 to the carburetor or injectorapparatus, a drain boss 48 and a drain plug 49. The upper end of the outlet 41 is recessed to receive and fixedly hold the tube-like bottom extremity of a cup-shaped deflector 50. A cylindrical sieve or screen 5i, sealed to the open upper end of the housing 44 by means of a gasket 52 and the cover plate 45, has its lower tube-like extremity adapted to be piloted into that portion of the deflector 50 which projects downwardly into the upper end of the outlet 41. The underside of the cover plate 45 is provided with an annular flange 53 to which is attached the open end of a cupshaped float guide 54. The bottom of the float guide 54 is provided with a small cup-shaped guide 55 adapted to receive the lower extremity of a valve mechanism indicated generally at 56. The valve mechanism includes a tube 51. fixedly secured to casinghalves 58 and 58 of a float 59, which may be internally reinforced, if desired, by enclosing therein a body of light-weight material, such as wood. Said tube is provided at its lower extremity with an outer collar 60 and an inner collar 61, fixedly connected thereto by means of a pin 62. A collar 63 is soldered or otherwise fixed interiorly of the uppermost extremity of said tube 51, and provides guidance for a needle valve 64, which is connected to a valve stem 65. A coil spring 66 surrounds the stem 65, within the tube 51, with the ends of said spring reacting against the base of valve 64 and the inner collar H at the lower end of said tube. The base of the needle valve 64 is flanged outwardly to abut the end of collar 63 limiting upward valve movement with respect to the tube 51 under influence of the spring 66. A passageway 611s provided through a boss 68 formed in the cover plate 45, and a valve seat 69 is fixed therewithin. Thus, with the valve 64 in down position, as in Figure 2A, the interior of the housing 44 is in direct communication with the vent conduit 36 through passageways 1|, 12, 13 and 14. The vent conduit 38 is in turn in communication with the atmosphere through the fuel storage container 30 and vent pipe 32, as shown in Figure 1. In Figure 2 three positions of the float 59 are shown. These are indicated, respectively, by dotted lines 59, the full line position 59 of the float and dotted lines 59. The float at position 59 causes the parts of its valve structure to remain in the position of Figure 2A by gravity. This position will be maintained all during the time fuel is rising within the eliminator to the fuel level indicated by the line i! at the left side of Figure 2. When the fuel level rises to the level 2 the fioat 59 will rise from position 59 to its full line position 59', and the float valve will assume the position shown in Figure 2B. In this position the valve 64 has just been closed against the seat 69, but there has not been enough buoyancy produced in the float to compress the spring 33. Therefore; the flange on the lower end of the valve 54 is still in contact with the lower end of the stop collar53.
When the liquid level rises higher, as to the line 2 in Figure 2, then the float will rise to position 59 as its buoyany has overcome the spring 65. The valve 54 is now under spring pressure and also under pressure as a result of the buoyancy of the float, the parts of the float valve being then in the position illustrated in Figure 2C with the lower end of the stem 65 against the pin 52. The significance of this particular position will hereinafter appear.
Finally the liquid level rises higher within the eliminator 33 as seepage of air and vapors occur through the valve seat 59 surrounding the valve 54. The buoyancy of the float thereby effects further compression of the valve against the seat. A
In the pressure responsive switch 40, a cylindrical housing 15 is separated into an upper and a lower cavity 15 and 11, by means of a common wall 13. A bellows 30 is designed to seal the lower cavity 11 from fluid intercommunication with a tapped hole 8| in the cover plate 45, leading directly into the interior of the housing 44 of the air-vapor eliminator 33. The outermost edges of the bellows are firmly clamped between a flange 92 formed integrally with the lower end of the housing 15, and the upper outermost surface of the cover plate 45 with a gasket 93 interposed therebetween. The space between the top surface of the bellows 99 and the inner surface of the lower cavity 11 is directly vented to the atmosphere by means of a passageway 84 formed in flange 92. Two electrical binding posts 85 and are fixed to the top of a dome 91 of insulating material (having a number of lightening holes drilled therethrough). Cut-outs 88 are provided in the uppermost dome surface for installation of a fixed contact 99, short coupled to the binding post 95, and a movable contact 90, long coupled to the binding post 85 by means of spring leaves 9|. The mid-portion of the leaves 9| is raised or lowered with reference to the base of a bellows stem 92 by vertical adjustment of a nut 93 threaded on the upper end of the bellows stem 92. By means of this adjustment, spacing of the contacts 89 and 90 may be varied to any desired gap. Prior to assembly of the above electrical parts, a washer 94 is slipped over the reduced upper portion of the bellows stem 92, a gasket 95 is placed in the bottom of the upper cavity l6, and a thin flexible diaphragm 95 is placed over the aforesaid two parts. A spring 91 and'spring retaining washers 99 and 99 are next added, after which the dome assembly described above is positioned as shown in Figure 2, and the nut 93 is screwed down to the desired adjustment. The assembly is completed and mechanism enclosed within the upper cavity by final addition of a dust cover Hit.
The air-vapor eliminator 33 and the pressure responsive switch 49 described immediately above operate as follows:
Under empty tank condition, the lowermost extremity of the valve mechanism 55 rests against the bottom of the cup-shaped guide 55 as shown in Figure 2A. Under such-down condition of the valve mechanism 55, the interior of the housing 44 is freely vented to the atmosphere through the passage 51, seat 59, passages H, l2, l3 and I4, vent conduit 39, fuel container 30, and vent pipe 32 to atmosphere, as may be readily seen by joint reference to Figures 1, 2 and 2A. Upon introduction of fuel through the inlet 46 provided in the base of the air-vapor eliminator 33, the fuel level within the housing 44 builds up to the level 2' within the housing 44, and the float 59 thereafter starts to rise, ultimately assuming its full up position, with the needle valve 54 sealing the central aperture provided in the valve seat 69, as already described.
Considerable importance is attached to the operation of the needle valve 54 with relation to the flow of fuel from the reservoir 59 to the carburetor and with relation to the venting of air or vapors through the conduit 38. After the level of fuel has reached the line 2 and the buoyant force of the float is at maximum,since the upper end of the tube 51 is stopped against a shoulder in the valve seat 59 as shown in Figure 20, it will be obvious that the needle valve 54 is maintained under predetermined pressure of the spring 55 and the buoyant force of the liquid displaced by the float in its uppermost position against the valve seat 59.
'I have found that where a line contact of metal-to-metal faces is employed, as in my disclosure, there is slight seepage of air past the needle valve and through the valve seat. Accordingly the air and vapors above the line 2 will graduallybe eliminated so that the entire eliminator 33 above the line 2 to the valve seat 59 will ultimately become filled with liquid. Actual operation of my fuel system in airplanes. indicates that the trapped air just referred to, is thus gradually driven out through the vent conduit 38 until the housing is completely liquid filled. Apparently when the liquid reaches the valve seat, it forms a film which prevents seepage of fuel but will permit any seepage of air when once the level of the fuel recedes below the level of the valve seat. 9
Assuming that the chamber of the air eliminator is completely filled with liquid and the buoyant force of the float is positioning the needle valve in seated relation with the valve seat under whatever tension has been built up in the spring 56 by the buoyant force of the float and/or vapor will cause a displacement of the fuel through the discharge opening 41, which leads to the carburetor and the float 59 as soon as the level of the fuel begins to fall below the. position 59.
When the level of the fuel recedes to a position approximately as indicated by the fuel level line 2', the lost motion between the flange on the lower end of the needle valve 54 and the lower end of the stop collar 53 in Figure 20 will be taken up as in Figure 2B, and any further lowering of the fuel level will open the valve. Thus, as the float moves downward in response to a decrease in the volume of fuel in the housing 44 and increase in the volume of gas or vapor, the float arrives at a position where its buoyant force no longer acts upon the valve to keep it closed. Just prior to opening of the valve however it remains seated under the force the float and the flange on the lower end of the valve 64 for eventually opening the valve as the float is further lowered, due to the displacement of the fuel by the accumulating vapor and gases. There will be a rapid discharge of the vapor and gases during the short interval of time that the level of the fuel lowers from the line 2 to the line 2 which, it will be noted, 'is a relatively short distance, thus providing a relatively close differential of operation for the float operated valve. Thus, for a limited displacement of the float due to displacement of the fuel by the accumulating gas or vapor, the needle valve is held in closed position by the action of the spring which varies in its resistance from a maximum when the float raises the tube 51 to the position shown in Figure 2C and to a minimum when the float is positively engaged with the valve (lower end of the collar 63 with the flange of the valve 64 in Figure 2B) for thereafter unseating the valve as the float lowers further. It is desirable that the distance of travel of the float from the position of maximum spring pressure on the float valve 64 to the position of positive unseating engagement of the float with the valve will be of a substantial length so that comparable quantities of gas and air are permitted to accumulate in the eliminator during the transfer of fuel from the source or supply tank to the carburetor, without bringing about a complete opening of the valve. The time delay in the opening of the valve, brought about by the action of the spring during the time that the float is being lowered, serves to prevent the discharge of liquid through the air or vapor discharge seat 159 which would otherwise take place were the valve to open'immediately with the accumulation of air and vapor in the eliminator and particularly where the pressure in the eliminator is of comparatively high-value.
Furthermore, the delay in opening of the valve serves to maintain in the fluid path from the source to the carburetor a substantially constant pressure at such time when the fuel is supplied to the carburetor only from the reservoir. The delay in opening of the valve also serves to provide an interval of time during which, when the reservoir chamber is being emptied, an indication or signal may be given to the operator under control of the switch contacts 89 and '90 while the carburetor is still acting under normal pressure.
It is of course important not to delay the opening of the float valve too long as it is desired to prevent the complete displacement of the fuel from the reservoir in order to avoid a failure of supply of fuel to the carburetor. In other words, it is desired to open the float valve completely at a time when there is still a small quantity of fuel in the reservoir cup 50.
Repositioning of the switch parts causes contacts 89 and 90 to be separated to the position shown in Figure 2. So long as the aforesaid predetermined fuel pressure is maintained or exceeded, the contacts 89 and 90 will remain in this 'open position. However, in the event of continued operation of the fuel system with the fuel storage container or tank 30 in an "empty" condition, the fuel pump will no longer be able to and more particularly the cup-deflector 50 of the air-vapor eliminator 33 will serve as a reserve reservoir for limited auxiliary fuel delivery to the carburetor or fuel injector apparatus, to maintain operation of the engine for a short period of time after the main fuel supply in tank 30 is "exhausted.
After predetermined depletion of the auxiliary supply of fuel in the bowl 50, the valve mechanism 56 will assume the "down position previously referred to above, and the bellows 80 will expand to a. down position, resulting in closing of the contacts 89 and 90. It may be understood that contacts 89 and 90 may control an electrical circuit for actuating a selector valve for automatically connecting another tank of fuel in the fuel supply system. It will therefore be apparent that closed contact" condition of the pressure responsive switch 40 is maintained as long as the fuel pump remains continuously connected with an empty fuel container, and open contact condition of the pressure responsive switch 40 is maintained as long as an uninterrupted supply of fuel is delivered to the fuel pump, and thence to the air-vapor eliminator 33. I
When the valve is closed, the gases can accumulate within the chamber and displace the liquid, thereby lowering the level thereof and consequently the position of the float, without opening the valve until such time as the float has approached the position when the float and valve are no longer relatively displaceable. Further displacement of the float by the accumulated gases will then cause opening of the valve.
As previously indicated, subject to certain limitations, the pressure responsive switch 40 can be directly connected to the outlet of the fuel pump through suitable pipe connection, in which case the tapped hole 8| provided in the cover plate 45 will be sealed by a suitable threaded plug (not shown). In that case the fuel system must incorporate an engine carburetor or an engine fuel injector (if the latter possesses its own air-vapor eliminator) that is directly connected to the outlet of its fuel pump; i. e., there is no air-vapor eliminator present. Also, the outlets of the fuel containers of the system must be provided with short standpipe extensions having a predetermined opening at the base of each. The latter provides a sumcient partial pressure drop to effect closed circuiting of the systems pressure responsive switch and at the same time assures a predetermined reserve fuel supply during the period in which switching from an empty fuel tank to a full fuel tank is taking place.
The modified form of air-vapor eliminator, shown in Figure 3, and designated 33a, is also adapted for use in low pressure fuel supply engine systems, either with a carburetor or fuel injector apparatus. In this construction the cupshaped housing 44 is closed at its upper end by a dome-shaped cover plate I45, and its lower end is provided with inlet 46, outlet 41 and drain boss 48 and plug 49, as in the construction above described with respect to Figure 2. The upper end of the outlet 41, inside the housing 44, is formed to receive a threaded collar I46, having an andeliver fuel to the inlet 46 and the housing 44,
nular flange for tightly clamping the bottom portion of .the cup-shaped deflector 50, in fixed spaced relation to the internal wall of said housing; The top marginal portion of said deflector cup is inwardly offset and surrounding said marginal portion is an annular sealing gasket I48,
An annular screen or sieve I43, having top and bottom annular reinforcing anchoring rings I56 and II is mounted between the upper end of the deflector cup 66 and the cover plate I45; the top ring I50 being seated in a recess formed in the. upper end of said housing 44 while the bottom ring is firmly fltted against the sealing gasket I46,
The cup-shaped float guide member 541s provided centrally in its bottom with a guide sleeve I53 into which extends a guide pin I54, mounted on the bottom ,of the float 59. The float is formed of top and bottom cup-shaped parts 564: and 59b, united together to form a sealed chambered float. The upper end of the float is provided with an upstanding tubular sleeve I56, the upper end of which is slidably guided in the annular wall portion of the valve seat element 69,
mounted in a chamber I51, formed in the underside of the cover plate I45. Thus the guide sleeve I 53 and guide pin I54, together with sleeve I56 and the valve seat element 69, serve to provide guidance for the float 59 during vertical movement thereof. The extreme upper end of sleeve I56 is formed internally with a collar I59 to provide a guide bearing for the needl valve 64, the lower end of which is shouldered at 6441 to abut against the lower end of the collar I59 and limit the upward movement of said valve relatively to the tubular sleeve I56. The needle valve is urged to its uppermost position relatively to said sleeve I56 by a coil spring I6I, reacting against the top of the float and the shoulder 64a of said needle valve. A pair of passageways 61 are provided in the valve seat element 69 in communication with grooves 69a in th interior wall of said seat element, to permit passage of air and fumes and vapor when the float is partially raised, so that the upper end of sleeve I56 is slidable over said passages 61 without obstructing flow therefrom. When the valve 64 is in the down position as seen in Figure 3, the interior of the housing 44 is in direct communication with the vent conduit 38, through passageways H and 12, the conduit being connected with the threaded passageway 14 as shown in Figure 2, and as in the construction therein described, conduit 38 is in turn open to atmosphere through the fuel container 30, which is vented by pipe 32, as seen in Figure 1.
The air-vapor eliminator 33a operates as follows:
Under empty tank condition of the system, the float and valve mechanism are in a position as shown in Figure 3, and the interior of the 3 housing 44 is freely vented to atmosphere through passages 61, II, 12 and 14 and conduit 38 to th fuel container 30. Upon introduction of fuel through inlet 46, the level of the fuel in the housing gradually rises. sition indicated by the liquid level line 3 without operating the float valve 64. When the position 3 is assumed, however, the entire valve assembly consisting of parts 64, I56, I59 and I6I will have been elevated to the position illustrated in Figure 3A for closing the needle valve 64 against the seat 69. Thereafter, depending upon the tension of the spring I6I, the liquid level must rise to a somewhat higher level as, for instance, that indicated by the liquid level line 3 in Figure 3, which compresses the spring I6I and causes a stop sleeve I56 to engage the flange 64* of the valve 64 and thus positively seat the valve 64 under whatever buoyant force there may be acting upon the float 59.
It may assume the po- In some instances, when the float is completely submerged, this may be sufliclent to practically eliminate air or vapor seepage but whenever the float recedes as a result of accumulation of additional quantities of air and/or vapor and the buoyancy is reduced, seepage will increase and, if insufllcient to eliminate the accumulating air and vapor, the float will finally be lowered to cause positive engagement between the stop collar I59 and the ange I64 as in Figure 3A, and opening of the valve as in Figure 3., Th float and valve mechanism, whenever they are raised by a high fuel level within the eliminator 33, will remain ingsuch position as normal predetermined fuel pressure is maintained or exceeded, and while there is accumulation of air and vapor at a rate that does not exceed the rate of air and vapor seepage outwardly through the valve seat 69.
However, upon continued operation of the pump, when the fuel tank or container 30 is empty, fuel will no longer be fed through inlet 46, in'which event the deflector cup 50 serves as a reservoir for an auxiliary quantity of fuel for delivery to the carburetor or injector apparatus, to maintain operation of the engine for a. short period of time after exhaustion of fuel in the container. In connection with aircraft, this short period of time is adequate to effect switch over to another full fuel container, without retardation of the engine, and thus avoids, reduction in speed and power and thereby eliminates the attendant dangers which would result therefrom in requiring difficult maneuvering of the aircraft to avoid mishaps. During such interval of time, the float and valve mechanism lower upon depletion of the auxiliary supply of fuel in the cup 56, and, will, in the absence of a restoration of the fuel supply to inlet 46 within said period of time, again assume the position seen in Figure 3.
The modified form of air-eliminator shown in figure 4, and designated 33', and pressure switch sure fuel supply systems, such as in connection with a super-charged engine.
Due to the more or less schematic nature of Figure 4, I have reduced to a minimum the showing of details not involving modification, over the structure shown in Figure 2. The essence of novelty in Figur 4, over the showing of Figure 2, concerns slidable mounting of a float guide 336, which functions in a manner so that upon seating of the valve 64 in the valve seat 69, further increase in the liquid fuel level in the cupshaped housing 44 will cause vertical bodily movement of said float guide 336, against the compressive restraint of a spring 331, to a level resulting in opening of a switch composed of a flxed contact 336 connected to a binding post 339 and a movable contact 349 connected to a binding post 3. The contacts 338 and 340 perform the same functions as the contacts 89 and 90 of Figure 2. Upon exhaustion of the fuel container 39, operably connected to the passageway 14 of the air-vapor eliminator 33b (the same as in Figure 1), the reserve fuelcontained in the cupshaped housing 44 is pressure-fed through the outlet 41 by the spring 331, since continuing operation of the fuel pump prevents fuel escapage from the inlet 41 of housing 44.
In the construction represented in Figure 4. the following new or substitute parts employed include the slidable float sists of an annular ring 342 with vent holes 343 are especially adapted for use in high presguide 336 which coni and 344, a lower housing 345 depending from said ring, and provided with vent holes 348, and an upper housing 341 fixed to the top surface of the annular ring 342. The bottom of the lower housing 345 is sleeved at 51a to form a journal guide for the tube 51 of the float 59. The valve seat 69 is flxed in an aperture provided in the top of the upper end of an inverted cupshaped housing 341, so that it acts as a base guide for the spring 331. The outer diameter of the annular ring 342 is in turn guided by a cupped sleeve 348. Said sleeve is provided with vent holes 348" and 349*, and its upper end continues 1 into an outwardly extending flange 356, supported on a mounting gasket 35 I which in turn is seated upon the upper endof the housing 44. Immediately the top of the mounting flange 350 I'place'- ".a-thin annular disk 352 to the lower inner; face of which I fix the upper end of a flexible quid, sealing element or bellows portion 353. The lower end of the bellows portion. 353 is also fixed to the top surface of the annular ring 342; The utility of the latter bellows portion will be discussed in detail hereinbelow.
Mounted on the cup-shaped housing 44 is a cover plate-housing 354, secured thereto by conventional screw-lockwasher means 354. Formed in the housing 354 is a vertical cavity 355 in which is mounted a sleeve 356, adapted to act as a primary guide for the float guide 336. The top of the housing 354 includes a spring cavity 351; vent line passageways 12, 13 and 14, and a contactor pin hole 358. A contactor pin 359, of insulating material, is mounted for sliding guidance in said hole and has a major portion thereof depending from the bottom surface of a contactor housing 360. Upward movement of the pin 359 serves to open the circuit controlled by contacts 338 and 340, by engagement of said pin with the insulated movable contact 340, with respect to the grounded fixed contact 338. 010- viously, the fixed contact 338 may be insulated from the housing368, if desired. The contactor housing 360 can be fixed to a shelf 36I provided upon the top outer surface of the cover plate housing 354 by any of several well known conventional means.
The combined air-vapor eliminator 33 and pressure responsive switch 340 operate as follows: Assuming initial tank emptyf condition, fuel from the fuel pump first enters the inlet 46, spills over the top of the deflector 58, and then rises in the latter until it flows through vent holes 346, 343, 344, 349"- and 349 to an upward level approximating the middle of the last named vent hole. So far, air originally occupying the empty air-vapor eliminator 33 has found ready escape through the open valve seat 69 and vent passageways 61, 12, 13 and 14. Thereafter, further fuel flow divides itself in inner zone A and outer zone B. Due to air trap, the fuel in zone B does not usually progress to the top of the cupshaped housing 44. In zone A, however, fuel ultimately and completely fills the upper part of housing 341. When fuel in the inner zone A reaches a point slightly above the buoyancy level of the float 50, the valve 64 closes the valve seat 69. Thereafter, pressure from the fuel pump must be relied upon, if further liquid rise is to be accomplished within zones A and B. Ingress of further fuel, under steadily increasing pump pressure, causes the spring 331 to steadily compress, permitting corresponding upward movement of the float guide 336 and associated elements, until its uppermost surface engages the pin 353. So
long as the fuel pump continues normal functioning, the contacts 338 and 340 will remain in open-circuit" condition and the engine fuel injector or carburetor connected with the outlet 41 of the housing 44 will continue to receive fuel under a predetermined pressure. During the time interval of switch-over between an exhausted fuel container and another container of fuel, the engine fuel injector or carburetor will continue to be fed reserve fuel under pressure from the cup-shaped housing 44 of the eliminator 33 the volume of which is efiectively increased by the volume of fuel within the elevated housing 341. As the fuel passes out of the lower passageway 41, the housing 341 will be pressed downwardly by the spring 331 while the valve 64 remains closed and the pressure of the spring thus maintains pressure on the fuel itself. The quantity of fuel within the elevated housing 341 is thus moved bodily downward to supplement the supply within the reservoir cup 50 with the spring 331 furnishing pressure for the supplemental fuel. Finally, however the lever of thefuel recedes to such a point that the valve 64 opens and thereafter there can be only gravity feed of the reserve fuel. Long prior to this however and, in fact, when the housing 341 starts to move downwardly, the switch 340 is closed for operating an indicator or means to supply further fuel to the eliminator.
With reference to the form of invention shown in Figure 5, the primary purpose in this embodiment is to make provision for the prevention of overflow. of the reserve fuel in the reservoir upon the eliminator being tilted to different angles when utilized in an airplane.
In general, the construction shown in Figure 5 is similar to that shown in Figure 3 and accordingly the same reference numerals have been used for parts which are similar. The parts which differ are as follows: An outer housing I64'is used to replace the housing 44. Within the housing I64 a similarly enlarged reservoir cup I65 takes the place of the reservoir cup 63 l of Figure 3. The purpose of enlarging the parts I64 and I65 in this manner is to secure an increased quantity of reserve fuel in the eliminator, indicated generally as 33 in Figure 5. The reservoir cup I65 has an inwardly flared upper edge indicated at I66, preferably at such an angle as to maintain a substantially constant effective opening in the space between the flared flange I66 and a constricting portion I61 of the upper housing I45. The. substantially constant effective opening between the portions I60 and I61 will have a tendency to provide a constant rate of fuel flow between these twoparts as the fuel passes from the upper end of the space between the parts I64 and I65, and spills over into the interior of the part I65. When the air eliminator I33 is tipped due to the airplane itself assuming an angle to the horizontal, as when taking off, the flared flange I66 will retain a considerable quantity of fuel within the reservoir cup I65, if it so happens that the fuel pump is running out of fuel at this particular time and the selector valve of the fuel system is being switched over to another fuel tank.
By way of illustration, assuming that the dash lines I68 indicate level position when the eliminator is thus tipped, it will be obvious that the level of fuel will be up to this line, whereas without the flange I66, it would come only up to a line I68.
A further important desideratum of the embodiment of the invention shown in Figure 5 is the provision of an air eliminator in which the duration of time for building up the pressure therein to the predetermined carburetor value is reduced to a minimum consistent with the required volume for the reserve fuel in the reservoir chamber, and consistent with obtaining the desired operation of the float valve during the time when the eliminator is beingfllled up with fuel under pressure.
For the purpose of reducing this time interval, the volume of the air eliminator chamber is reduced at the upper end by shaping the chamber in the form of a bottle-neck, the constricting part being indicated at I 61 and the constricted part at. "0. Accordingly, the valve 64 will re-' main open as in Figure until the level of the liquid builds up to the line 3, after which the level rises quickly because it rises within the constricted part I'll.
When the level reaches the line 3a, the valve will be closed as in Figure 3A and thereafter further rise of the liquid level will impose spring tension on the valve and finally positive engagement of the valve with its seat under buoyant force of the float as in Figure 3B.
It will be seen that the time required to completely flll the air eliminator chamber with liquid and establish the predetermined pressure therein will depend upon the rate of fuel flow and the capacity of the eliminator chamber above the reservoir chamber. Thus, for any given rate of fuel flow into the chamber, the time interval will be a minimum if the capacity of the eliminator above the reservoir is a minimum. It is, however, impossible to completely eliminate the space above the reservoir chamber and yet enable the float to i move and regulate the control valve and thereby the elimination of accumulated air and vapor from the eliminator 33c. The space of the eliminator chamber above the reservoir is therefore delimited at I10, and is delimited by the time operation of the valve at such time when the reservoir is being emptied for lack of a replenishing supply and by the desirability of reducing to a minimum the time required to completely fill the eliminator with fuel and establish the desired pressure therein.
It will also be obvious that if the capacity of the eliminator chamber above the reservoir chamber is reduced to a minimum, then for any given rate of flow, the time delay operation of the float-controlled valve will likewise be reduced to a minimum, and that therefore for any time delay operation of the float-controlled valve there will have to be a corresponding capacity of the air eliminator chamber above the air reservoir chamber since the position of the float within the chamber and consequently the position of the valve, will depend upon the level of the liquid in the chamber. In order therefore to reduce the time interval of filling the air eliminator chamber completely with fuel within an optimum minimum duration of time and to retard or..delay the complete opening of the valve during a time when the air eliminator chamber is being emptied for a maximum optimum duration, the air eliminator is provided at its upper portion with the bottle-neck portion just described that cooperates with the float to provide three zones of different capacity. The first zone is within the reservoir chamber, the part I61 forming a transition of this zone; the second one is within the constricted part I up to the top of the float, and the third zone is from the top of the float up to a head member Ill of the eliminator 33c. Assuming a constant rate of inflow of fuel and after it will rise gradually within the first zone,
its velocity will be substantially increased in the second zone and will slow down again in the third zone. The result is a relatively quick or snapacting closing of the valve while the fluid is rising in the second zone and a slowing down of the rising fuel in the third zone so that none of it is carried by momentum out through the valve seat 68.
During rise of the fuel level inthe constricted part I10, its rise will first occur ahead of the float as the float will, due to its inertia, lag behind the rising fuel. When the float starts to move however it will be carried by its own momentum to a closed position somewhat faster than the rising of the fuel itself, although the air above the float will somewhat cushion the valve closing, thus resulting in comparative quiet operation without any hammering effect.
The float support 54 in Figure 5 is provided with openings Sla and 54b which permit the liquid to flow in and around the float and this liquid will, upon flowing through the openings 54b, impinge the'top of the float thus aiding in the cushioning effect as well as in hastening the response of the float to the level of the liquid which'rises more slowly inside the float support 54 than outside of it. All of these factors in cooperation produce a float waive of the desired operating characteristics.
Although I have herein shown and described certain preferred forms of my invention, manifestly it is capable of further modification and rearrangement without departing from the spirit and scope thereof. I do not, therefore, wish to be understood as limiting this invention to the precise embodiments herein disclosed, except as I may be so limited by the appended claims.
1. An air-vapor eliminator for use in a fuel dispensing system comprising, a housing having a float chamber, a float mechanism disposed within said chamber, said housing having an airvapor discharge passageway adjacent its upper end and fuel inlet and outlet openings adjacent its lower end, a valve seat in said air-vapor discharge passageway, valve means carried by the float mechanism and adapted to interact with said valve seat for effecting opening of said valve and thereby free discharge of air or vapor through said passageway upon low fuel and float mechanism level, said valve seat and valve means being both of metal presenting line contact with each other, and spring means between said float and valve for effecting seepage discharge of air or vapor through said passageway with the valve retained seated under the combined constraint of said spring and the buoyance of said float upon high fuel and float mechanism level and effecting sealing of said valve seat against fuel flow therethrough when the level of fuel reaches said seat and provides a film of liquid between it and the valve means while the valve means is being retained against said seat under such combined constraint.
2. An air-vapor eliminator for use in a fuel dispensing system comprising, a housing having a float chamber, a float mechanism disposed with in said chamber, said chamber having a metallic valve seat and an air-vapor outlet interconnected with each other, and having fuel inlet and outlet openings and metallic valve means carried by the float mechanism and adapted to interact by line contact with said valve seat for permitting free air-vapor escapaae through said air-vapor outlet until predetermined rise of said float mechanism has closed said valve, spring means acting on said valve to retain it seated under an increasing constraint of the spring means and thereby permitting air-vapor seepage esczapage through said air-vapor outlet during a further predetermined distance of rise of said float mechanism and as the fuel rises to the level of the valve seat and preventing fuel escapage through said air-vapor outlet after seepage escapage has occurred sumciently to permit the fuel level to rise to said valve seat with the valve then retained seated under the maximum constraint of said spring means.
3. An air-vapor eliminator for use in a fuel dispensing system comprising, a housing having a float chamber, a float mechanism disposed within said chamber, said chamber having a valve seat and an air-vapor outlet interconnected with each other and having fuel inlet and outlet openings communicating. with said chamber, and valve means operated through a two direction limited motion, spring biased connection by said float mechanism and adapted to interact with said valve seat by means of line contact for progressively permitting free air-vapor escapage, permitting air-vapor seepage escapage and preventing air-vapor escapage through said air-vapor outlet by a progressive rise of the fuel level acting on said float mechanism.
4. An air-vapor eliminator for use in a fuel dispensing system comprising, a housing having a float chamber, a float mechanism disposed within said chamber, movable guide means for the float mechanism mounted for vertical movement in the chamber, said chamber having an airvapor discharge passageway adjacent its upper end and fuel inlet and outlet openings adjacent the bottom of the chamber, the upper end of said guide means being in the form of a substantially I closed dome sealing the upper end of the chamber and enclosing the float, a valve seat element carried on the upper end of said guidemeans and provided with a port providing communication between opposite sides of the dome in said chamber, valve'mechanism carried by the float mechanism and adapted to co-act with the valve seat element for closing said port against discharge of air-vapor to the upper end of the chamber and thence through said passageway upon predetermined elevation of said float and guide mechanism, and spring means normally opposing upward movement of said guide means in the chamber.
5. An air-vapor eliminator for use in :a fuel dispensing system comprising, a housing having a float chamber, a float mechanism disposed within said chamber, movable guide means for the float mechanism mounted for vertical movement in the chamber, said chamber having an airvapor discharge passageway adjacent its upper end and fuel inlet and outlet openings adjacent the bottom of the chamber, the upper end of said guide means being in the form of a substantially closed dome, sealing the upper end of the chamber and enclosing a float, a valve seat element carried on the upper end of said guide means and provided with a, port providing communication between opposite sides of the dome in said chamber, valve mechanism carried by the float mechanism and adapted to inter-act with the valve seat element for controlling the discharge of air-vapor to the upper end of the chamher and thence through said passageway upon predetermined fuel actuation of said float and guide mechanism, a bellows for controlling actuation of said guide means independently of said float mechanism, and spring means normally opposing upward movement of said guide means in the chamber.
6. An air-vapor eliminator for use in a fuel dispensing system comprising, a housing having a float chamber, a float mechanism disposed within said chamber, movable guide means for the float mechanism mounted for vertical movement in the chamber, said chamberhaving an airvapor discharge passageway adjacent its upper end and fuel inlet and outlet openings adjacent the bottom of the chamber, the upper end of said guide means being in the form of a closed dome, sealing the upper end of the chamber and enclosing the float, a valve seat element carried on the upper end of said guide means and provided with a port providing communication between opposite sides of the dome in said chamber, valve mechanism carried by the float mechanism and adapted to inter-act with the valve seat element for controlling the discharge of airvapor to the upper end of the chamber and thence through said passageway upon predetermined fuel actuation of said float and guide mechanism, and spring means normally opposing upward movement of said guide means in the chamber.
7. In an air-vapor eliminator for use in a fuel dispensing system, a housing having a float chamber, an inverted cup member therein and guided for vertical movement relative thereto, a float mechanism disposed within said cup member, said float chamber having fuel inlet and outlet openings and having an air-vapor discharge passageway adjacent its upper end, said cup member sealing the upper end of said float chamber, a valve seat element carried on the upper end of said cup member and provided with a port providing communication between the interior of said cup member and the sealedspace thereabove withinsaid float chamber, and valve mechanism carried by the float mechanism and adapted to inter-act with said valve seat element for controlling the discharge of air-vapor therethrough and thence through said passageway in response to actuation of said float mechanism and cup member by changes in fuel level in said float chamber.
8. An air-vapor eliminator for use in a fuel dispensing system comprising, a housing having a float chamber, a float mechanism disposed within said chamber, movable guide means for the float mechanism mounted for vertical movement in the chamber, said chamber having an air-vapor discharge passageway adjacent its upper end and having fuel inlet and outlet openings, the upper end of said guide means being in the form of a closed dome sealing the upper end of the chamher and enclosing the float, a valve seat element carried on the upper end of said guide means and provided with a port providing communication between opposite sides of the dome in said chamber, valve mechanism carried by the float mech-- anism and adapted to inter-act with said valve seat element for controlling the discharge of airvapor to the upper end of the chamber and thence through said passageway in response to actuation of said float and guide mechanism as a result of fuel level changes in said chamber, and spring means normally opposing upward movement of said guide means in the chamber and eflective, upon cessation of flow of fuel to the chamber, to displace the fuel therefrom through said outlet.
9. An air-vapor eliminator for usein afuel dispensing system comprising, a housing having a reservoir and float chamber, said chamber having fuel inlet and outlet openings adjacent its lower end, an upwardly opening receptacle mounted within said housing to provide, on the outside of the receptacle a fuel passageway in communication with the inlet opening, the inside of said receptacle serving as an auxiliary fuel reservoir in communication with said outlet-opening, and said receptacle, at its upper end, having an inturned flange to effect retention of a substantial quantity of reserve fuel when said eliminator is in tipped position.
10. In an air-vapor eliminator for use in a fuel dispensing system, a housing having a float chamber constricted at its upper end, a float mechanism disposed within said chamber, said chamber having fuel inlet and outlet openings adjacent its lower end, an upwardly opening receptacle mounted within said housing below the constricted upper end thereof to-provide, between said receptacle and said chamber, a fuel passageway in communication with said inlet opening, the inside of said receptacle serving as an auxiliary fuel reservoir in communication with said outlet opening, and said receptacle having an inturned flange at its upper end to retain reserve fuel within said receptacle when the same is in tilted position.
11. In an air-vapor eliminator for use ina fuel dispensing system, a housing having a float chamber constricted at its upper end, a float mechanism disposed within. said chamber and substantially fllling said constricted upper end air and vapor in response to different positions of said float mechanism under valve open and valve closed conditions and to at all times prevent escape of fuel through said valve seat under valve closed condition and when the level of the liquid rises to said seat.
12. An air-vapor eliminator for use in a fuel supply system of an internal combustion engine comprising, a housing having a float chamber,
a float mechanism disposed within said chamber,-
said housing having an air-vapor discharge passageway and fuel inlet and outlet openings, a metallic valve seat in said air-vapor discharge passageway, and metallic valve means actuated by said float mechanism and adapted to so co-act by circular line contact with said valve seat as to effect free discharge of air or vapor through said passageway upon low fuel level and low float mechanism position, eifecting seepage discharge of air or vapor through said passageway upon high fuel level and high float mechanism position and eifecting sealing of said valve seat against fuel flow therethrough when the level of fuel reaches said seat, said valve means being mounted with limited lost motion on said float mechanism and spring urged to its extendedposition to effect such action of said valve means.
13. An air-vapor eliminator for use in a fuel supply system of an internal combustion engine comprising, a float chamber having a valve seat and an air-vapor outlet inter-connected with each other, a float mechanism disposed within said float chamber, and valve means actuated by said float mechanism and adapted to inter-act through line contact with said valve seat for preventing fuel escapage through said valve outlet, but enabling air-vapor seepage of air therethrough after predetermined rise of fuel in said float chamber and consequent predetermined rise of said float mechanism relative to said float chamber, said valve means being telescopically mounted with respect to said float mechanism and limited in both directions relative thereto, and spring means biasing said valve means toward one of its limits to eifect the recited action of said valve means.
' DAVID SAMIRAN.