CA1200769A - Vent for fuel-water separator - Google Patents

Abstract

Abstract of the Disclosure A fuel-water separator having a plurality of spaces is provided with a vent. The vent includes an inlet having a float disposed in the inlet. An outlet portion is provided which opens into a space in the separator different from the space communicating with the inlet portion. The outlet communicates with the inlet through an air passageway. In a separator having an element which restricts the flow of air through the separator, the vent and air passageway direct air collected on the upstream side of the air-restrictive element to a space in the fuel-water separator downstream of the air-restrictive element.

Description

~2~'~ 4005-186 This invention relates to fuel line devices, and more part:icularly to a fuel-water separator having a vent to vent air which collects on the upstream side of an air-restrictive portion of the fuel-water separator to a location in the separator down-stream of the air-restrictive portion.
Fuel for internal combustion engines is often contami-nated with impurities such as particulate matter and water which become entrained in the fuel. The presence of these impurities can deleteriously affect engine performance. The problems associ-ated with entrained impurities are especially acute with diesel engines, as diesel Euel tends to be more highly contaminated than gasoline.
To solve the above-mentioned problem, it is often advis-able to install filters and fuel-water separators in the fuel line to trap entrained particles and separate entrained water from the fuel, respectively.
In fuel-water separators, it is often advisable to employ filters, surface tension discriminators, or a series there-of which are capable of separating line water particles which be-2Q come entrained in the fuel, and which are not normally fully re-moved by centrifugal or gravitational separation.
One of the difficulties encountered with the use of filters and separators is that the filters and separators often in-clude media which can become substantially air-impermeable. A
fuel-water mixture which passes through a fuel line often contains air entrained in the mixture. Also, ,~t

-2- ~
.~,, air will often be introduced by opening an air bleed valve during water drain operations. This air will normally not pass through these air-restrictive media, and collects in the portion of the fuel path adjacent to and upstream of the air-restrictive media. In a separator having a surface tension discriminator, the air will usually collect in the space adjacent to and upstream of the surface tension discriminator.
The air pocket which forms adjacent the media prevents the entire surface of the media from being utilized 10. to pass fuel and coalesce entrained water. As the air pocket increases in size, only the portions of the discriminator are utilized. This can result in a decrease in the amvunt of fuel flowing through the media, thus decreasing the filter or separator's fuel-handling capacity. Further, the formation of an air pocket adjacent the media will cause the media to dry out.
One way to remove the collected air from fuel-water separators is to periodically open the top of the separator and pour diesel fuel into the top of the separator to 20. displace the air collected therein. This solution, howevPr, is unsatisfactory in that it requires the user to partially disassemble the separator on a fairly regular basis. It is preferble to have an automatic air-removal means which obviates the need for owner involvement in the removal of collected air.
In accordance with the present invention~ in a fuel path having an air-restrictive element which restricts air passage between a portion of the fuel path upstream of the air-restrictive element and a portion of the fuel path downstream of the air-restrictive elemen~, a vent is provided for venting air which collects in the portion of the fuel path upstream of the air-restrictive element to a portion of the path downstream of the air-restrictive element. The vent includes an inlet and an outlet. An air passageway leads from the inlet to the outlet. An element~ for instance, a venting valve, is provided for restricting the flow of fuel from the inlet to the outlet while permitting air to flow from the inlet to the outlet.
In a fuel-water separator having an air-restrictive 10. barrier, the venting valve and air passageway can, in one preferred embodiment~ serve to conduct air which collects in a space in the fuel-water separator upstream of the air-impermeable membrane, to a space in the separator downstream of the air-restrictive barrier.
One feature of the instant invention is that a means is provided for removing air which collects from the space adjacent, and on the upstream side of, an air-restriction media in a fuel path, such as a surface tension discriminator in a separator. This feature has the 20. advantage of preventing the media from drying out. Further, it prevents an air lock from forming at the top of the media, which would impede fuel flow through the media~ By removing air from this space, the vent eliminates the need for opening the top of the separator or filter and the need for pouring diesel fuel into the top of the filter or separator to displace the air at the top of the filter or separator. It also prevents the need for pouring diesel fuel into the top of the filter or separator for the purpose of keeping the media from drying out. Further, when air is removed from the 30. upper portion of the media, the full axial length of the media is usable to pass fuel~ If an air lock forms, only the portion of the media beneath the air pocket is utilizable for passing fuel.
Another feature of a preferred embodiment of the instant invention is that a float is provided which is gravitationally biased to be disengaged from the seat. This feature has the advantage of allowing the air to be removed from the space as it accumulates. If the air were allowed to surge through the fuel line in large quantities, the engine 10. would run extremely roughly and possibly stop running.
A further feature of the preferred embodiment of the instant invention is that the float is designed to be floatable in fuel. This feature has the advantage of blocking off fuel 10w through the vent when the liquid level is high enough to float the valve. When the liquid level is high enough to cause the float to rise, the float seats against the opening and thereby closes it. This ensures that fuel which reaches the engine will have travelled through the entire separator, and thus be 20. substantially water-free. Also, another advantage of employing a float which is floatable in fuel is that before the float will rise high enough to close off the passageway, the space adjacent to the surface tension discriminator will normally be devoid of air. Due to the density of air being much less than the density of fuel, the air which collects in the space upstream of the air-impermeable surface tension discriminator will tend to rise to the upper portions of the space ad~acent the surface tension discriminator, and thus be in closer proximity to the passageway than the liquid which 30. is flowing through the space.

It is also a feature of the preferred embodiment of this invention that the air passageway opens into a space in the uel path beyond the air-restrictive element. The air which travels through the passageway may well contain substantial quanities of vaporized fuel. This fuel-vapor-laden air is directed back into the fuel path and ultimately to the cylinders. Thus, the fuel-laden air is not emitted into the atmosphere, thereby preventing increased bydxocarbon emissions from the vehicle.
10. These and other ~eatures of this invention and their inherent advantages will become apparent to those skilled in the art from the following description of preferred embodiments and the accompanying drawings illustrating the best mode of carrying out the invention, wherein:
Fig. 1 is a cross-sectional view of a fuel-water separator embodying the invention showing an arcuate-shaped rim;
Fig. 2 is an enlarged, partial view of the 20. inven~ion with the float in the closed position showing a frustoconical rim: and Fig. 3 is a top cross-sectional view of the invention, taken along the lines 3-3 of Fig. 1.
Referring to the drawings, Fig 1 shows the fuel-water separator 8 of the present invention, comprising an upright cylindrical housing 10 having a lower can or can portion 12 and an upper cover or cover portion 14 joined together to provide a seal between the cover 14 and can 12.
Fuel enters the separator 8 through a port 16 and exits through a port 18 }7~

A central opening 20 is formed at the bottom of the can portion 12 of the housing 10 to provide a drainage port for water accumulated at the bottom of the can 12. A
petcock 22 is threaded into a threaded tube 24 brazed into the central opening 20. By opening and closing petcock 22, drainage of the water from can 12 can be controlled.
Inside the housing 10 is a circular plate 26 having a plurality of holes or openings 28. The diameter of the plate 26 is less than the diameter of the can 12 so that a 10. circumferential space 30 is provided between the outer peripheral edge of the plate 26 and the can 12 for channeling water to the bottom o the can 12.
The plate 26 is provided with an opening 32 concentric with a downwardly extending sleeve 34. The lower edge of the sleeve 34 rests upon a retainer for a ball 36.
This ball 35 can move upwardly and downwardly in the retainer in a space defined by peripherally spaced-apart, vertically extending legs 38. Legs 38 define a plurality of drainage opening spaces therebetween. The ball 36 rests upon a seat 20. formed at the bottom central opening 20 of the can 12.
A drainage tube 40 extends downwardly through the opening 32 in sleeve 34. The lower end of tube 40 provides an upper stop for the ball 36. The lower end includes a plurality of reliefs or notches 42 which provide drainage relief and which prevent the ball 36 from sealing off the bottom of the tube 40.
Mounted on or connected to the top of the plate 26 is a semicircular fuel passageway or raceway 44 which may have a cross-sectional inverted U-shape. This passageway 44 30. is designed to apply a centrifugal force to the fuel-water 37~3 mixture passing therethrough. The fuel enters the passageway 44 at point 45 and moves clockwise through the passageway 44.
About the last one-third of the radially outer peripheral wall of the passageway 44 is provided with openings 46. The fuel-water mixture continues to move through the passageway 44 and exits through the end (not shown) of the passageway.
The liquid mixture passes through the openings 48 and moves into a first space 50 above the cover 52. Separated water, which is still entrained in the liquid mixture after the 10. centrifugal action, may fall by gravity along the downwardly sloping upper wall 54 of the cover 52 and into the bottom of the can 12.
The first space 50 into which the liquid moves after leaving the centrifugal section 56 is illustratively defined by the upper wall 54 of the cover 52, the conical flange portion of the tube 40, as well as by the bottom and side of an outer cup 58. The space 50 is also, as shown in Fig. 1, defined by the inner surface of the can 12. It will be seen that the conical flange provides a seat or support 20. for the rather shallow conically shaped bottom of the outer ~up 58.
The liquid in space 50 flows through a plurality of openings 60 into second space 62. A surface tension separator 64 is generally cylindrical and has an outer cylindrical wall, a low~r end, and an upper end which form an interior 65 of the separator out of which extends exit tube 18. Exit tube 18 conducts separated fuel from the fuel-water separator 8.
An inner cup 66 is provided over the surface

3~ tension separator 64. This inner cup 66 defines a third _~_ 3~7~

space 68. The third space 68 also has a plurality of openings 70 peripherally spaced about its upper edge for movement of the liquid mixture into the inner cup 66, and a plurality of openings 72 peripherally spaced about its bottom for movement of water toward the bottom of can 12. The shallow conical bottom of the cup 66 is provided with a concentric opening 74 forming an upper seat for a ball 76 captured in a ball retainer defined by a plurality of periphexally spaced-apart fingers 78 extending upwardly from 10. the flange portion of the drainage tube 40. The drainage tube 40 is formed to provide a lower seat 80 for the ball 76 with the seat 80 being below and concentric with the upper seat 74. The ball 76, therefore, can move between the upper seat 74 and the lower seat 80 in the vertical space defined by the fingers 78, Mounted concentrically about the inner cup 66 is a support cage ~2 providing a plurality of peripherally spaced-apart, axially extending openings 84. The retainer ring 86 has a plurality of peripherally spaced-apart openings 88 in 20~ the bottom web portion of the channel. The radially inner peripheral edge of ring 86 engayes the outer peripheral surface of the inner cup 66 just below the openings 72 in the cup 66. A sleeve 90 of untreated fiberglass media is placed on the cage 82. Another surface tension separator 92 is provided around the outer periphery of the sleeve 90.
In the illustrative embodiment, the surface tension separators 64, 92 separate fine water particles having a diameter of about 130-140 microns fxom the liquid mixture, These are water particles which are too small to be separated by centrifugal or gravi~y action~ The separator ~2C~7~i~3 64, 92 media may be either a monofilament polyester fiber woven into a cloth having a pore size of about 130-140 microns or a monofilament Teflo ~ screen having a similar pore size with approximately 100 fibers both horizontally and vertically per inch, i.e., 10,000 fibers/square inch. Each of these separator 64, 92 media will separate water particles of the diameter indicated and pass fuel in response to widely varying surface tensions between the two liquids. The separated water will flow down the outer surface of the 10. separator 64, 92 media.
Further, in the illustrative embodiment, sleeve 90 is a mat of untreated random length fiberglass fibers, comercially referred to as Class 5A fiberglass.
Surface tension separator 92, besides being substantially water impermeable, is also substantially air-impermeable. The air impermeability of surface tension separator 92 prevents air which is entrained in the liquid mixture from passing through the separator 92. Consequently, air tends to collect in spaces 50, 62. Due to the fact that 20. air is much less dense than water, the air will tend to rise to the upper portion of spaces 50, 62 and collect near openings 60. If enough air is allowed to collecty an air lock will be formed at the top of spaces 50, 62. This will cause the surface tension separator 92 to dry out. The drying out of surface tension separator 92 has the adverse effect of impeding fuel flow throu~h the fuel-water separator 84 Further, when an air lock forms at the upper portion of surface tension separator 92, fuel is unable to pass through the full axial length o the surface tension 30. separator 92.

~`g~7ti~

Venting valve assembly 94 is provided to remove air which collects near the top of spaces 50, 62. Disposed above spaces 58, 62 is the inlet 95 to venting valve 94. Disposed adjacent to spaces 50, S2 is plate 96 containing openings 98, through which fuel, water, and air can pass. Inlet 95 contains vertical wall 100 which preferably is the shape of a continuous cylinder. Cylindrical vertical wall 100 is preerably fluted, having a series of spaced-apart, axially extending ridges 101. Disposed above vertical wall 100 is 10. ceiling 102 which contains at its center opening 104~ At the junction of ceiling 102 and opening 104 is a rim 106 which serves as a seat for float 108. Float 108 contains a cylindrical lower portion 110 and a conical upper portion 112. Conical port1on 112 is sized and shaped to seat upon rim 106, so that when float 108 is in its closed position, as shown in Fig. 2, the engagement of the conical portion 112 to the rim 106 will form a substantially liquid tight barrier.
This will prevent fuel from escaping through the opening during times when no air is collected above the fuel. The 20. rim 106 may be arcuately shaped, as shown in the drawings or alternatively may be frustoconically shaped. Plate 96 serves as a lower limit to the movement of the float 108, preventing the float 108 from descending into spaces 50, 62.
Preferably, float 108 is sized so that the height of the float 108, measured from its apex 114 to its base, is greater than the distance between a pair of opposed flu~es 1O1D This prevents the float 108 from rotating about a horizontal axis.
The shape of float 108, and material from which it is made~ are selected to make the float 108 buoyant in fuel.
30. Preferably, the apex 114 and the upper par~ of the conical ~ ~?()~69 section 112 of the float 108 will remain above the surface of any fuel which enters inlet 95.
Disposed above opening 104 is air passage 116 which includes a vertically rising portion 118, a lateral portion 120, and a vertically descending portion 122. The lateral portion 120 carries air laterally fxom the outer portion of the separator above spaces 50, 62 to the inner portion of the separatorl adjacent to exit tube 18. Vertically descending portion 122 directs the air into outlet 124 which opens into 10. the interior 65 of the separator. The flow of the fuel into the lower portion of the interior 65 of the separator 64 and out the exit tube 18 will serve to create a partial vacuum upon the air contained in the air passageway 116. The air which travels through the air passageway 118 and out the outlet 124 will become re-entrained in the fuel, and will proceed out the exit tube 18 and into the fuel injectors of the engine and ultimately into the pistons. Although the entrainment of air into the fuel might cause the engine to run roughly for a while, it is contemplated that the volume 20. of air entrained in the fuel will not be sufficient to cause the engine to cease running.
Further, the air passa~eway can direct the air into another space within the separator such as space 68. This, however, is not preferred since space 68 is upstream of surface tension discriminator 64. As shown in Fig. 2, i~ may be advantageous for the vent valve assembly 94 to include a second inlet 126, and float 128, separate from inlet 95 and float 108 to vent air which collects near the top of space 68. The structure of inlet 126 and float 128 is similar to 30. the structure of inlet 95 and float 108. Air which collects in space 6B will cause much the same problem as air which collects above spaces 50, 62~
Keferring now to Fig. 1, the float 108 is shown in its open position. In its open position, the conical portion 112 of the float 108 is not engaged to the rim 106 of the opening. In this position, air is allowed to escape above the float 108 and out the air passageway 116. Referring now to Fig. 2, an enlarged cross-sectional view of the separator is shown, with the float 108 in its closed 10. position. In this position, the float 108 is floating upon fuel which has collected in inlet 95O ~he conical portion 112 is seated against rim 106, forming a substantially liquid-impermeable barrier. This prevents fuel from flowing through the air passage 116 and into the interior 65 of separator 64. This helps to ensure that fuel which flows through the separator 8 will pass through all of the sjpaces in the separator 8, and thus have full benefit of the separator's ability to separate the fuel from the water entrained therein.
20~ Referring now to Fig. 3, a top cross-section,al view of the separator ~ is shown wherein a plurality of vent valves are disposed about the circumference of the separator 8. The use of a plurality of venting valves ensures that air will be more efficiently removed from the upper portions of spaces 50, 62, and that an air pocket will not form at a side of a separator 8 distant from a venting valve 94, thus preventing the ventin~ valve 34 from venting the air out of the upper portion of spaces 50, 62.
Although the invention has been described in detail 30. with reference to certain preferred embodiments and specific examples, variations and modifications exist within the scope and ~pirit of the invention as described and as defined in the following claims~

Claims (17)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a fuel path having an air restrictive element which restricts air passage between a portion of the fuel path upstream of the air restrictive element and a portion of the fuel path downstream of the air-restrictive element, a vent for venting air which collects in the portion of the fuel path upstream of the air-restrictive element to a portion of the fuel path downstream of the air-restrictive element, the vent comprising:
an inlet means disposed in the upstream portion, an outlet means disposed in the downstream portion, a passageway leading from the inlet means to the outlet means, and an element for restricting the flow of fuel from the inlet to the outlet while permitting air to flow from the inlet to the outlet

2. The improvement of claim 1, wherein the restricting element comprises:
a float, buoyant with respect to fuel and water, disposed in the inlet, and a seat for engaging the float, the seat being disposed above the float, the engagement of the seat to the float causing the passageway to become closed.

3 The improvement of claim 2, wherein the seat comprises a substantially circular opening, and wherein the float includes a substantially conical portion for being received in the substantially circular opening.

4. The improvement of claim 2 or 3 and further comprising a plate disposed in the inlet below the float, the plate including an opening for fluid and air to pass therethrough.

5. The improvement of claim 2 wherein said float includes a substantially cylindrical portion, the inlet comprises a substantially cylindrical opening, the float has an outer diameter less than the inner diameter of the inlet, and the height of the float is greater than the inner diameter of the inlet.

6. The improvement of claim 2 wherein the float includes an upper conical surface for engaging said seat and wherein said seat comprises a rim which is sized and shaped to receive the conical surface of the float.

7. The improvement of claim 1 and further comprising a passageway from the inlet to the outlet, the passageway including a vertically rising portion disposed above the inlet, a lateral portion and a vertically disposed descending portion which terminates at the outlet.

8. A fuel-water separator comprising a container having entry and exit ports and means inside said container defining a progression of spaces through which the fuel moves from the entry port to the exit port, said space-defining means being disposed in said container to direct the fuel through a series of downwardly and upwardly directed paths as it moves through said spaces to cause the higher density water to move downwardly while the lower density fuel moves upwardly, said space-defining means further defining openings in the lower portions of said spaces through which the separated water drains downwardly, and a vent means for directing air from one of the spaces past one of the space-defining means.

9. The invention of claim 8, further comprising means providing a media in one of said spaces having a surface tension discriminating surface through which fuel will move, but which restricts the passage of air through the separator, wherein the vent comprises an inlet means disposed in one of the spaces, a float, buoyant with respect to fuel and water, disposed in the inlet, a passageway leading from the inlet means for directing air from the inlet to an outlet, and a seat for engaging the float, the seat being above the float, the engagement of the seat to the float causing the passageway to become closed.

10. The invention of claim 9, further comprising a plate disposed in the inlet below the float, the plate including an opening for fluid and air to pass therethrough, and wherein the seat comprises a substantially circular rim having an opening in the center of the rim, and the float includes a substantially conical portion for being received in the substantially circular seat.

11. The invention of claim 9 wherein the float includes a lower cylindrical portion, and an upper conical portion for engaging the seat, and the inlet comprises a substantially cylindrical opening having an inner diameter which is greater than the outer diameter of the float and less than the height of the float.

12. The invention of claim 9 wherein the outlet directs the air into a space through which fuel moves which is downstream in the progression of spaces from the surface tension discriminating surface.

13. A fuel-water separator comprising an upright container having an entry port and an exit port, an outer cup and an inner cup disposed in said container to define generally concentric first, second, and third spaces through which the fuel progressively flows between the entry port and exit port, said container and said outer cup defining said first space for receiving fuel from said entry port, said outer and inner cup defining therebetween said second space for receiving fuel from said first space, and said inner cup defining therein said third space for receiving fuel from said second space, said container and cups defining openings providing communication between said spaces adjacent the upper portions of said cups such that the fuel moves upwardly to move between said spaces, said inner cup having an opening at its bottom for draining separated water downwardly, said outer cup having an opening at its bottom for draining separated water downwardly, said container having an opening at its bottom for draining separated water downwardly and out of the container, and a vent means for directing air from one of the spaces to another of the spaces.

14. The invention of claim 13, further comprising an annular media concentrially disposed in the second space, and wherein the vent directs air from a space on one side of the annular media to a space on the other side of the annular media.

15. The invention of claim 13 or 14 wherein the vent means comprises:
an inlet means disposed in one of the spaces, a float, buoyant with respect to fuel and water, disposed in the inlet, a passageway leading from the inlet means for directing air from the inlet to the outlet, a seat for engaging the float, the seat being above the float, the engagement of the seat to the float causing the passageway to become closed, a plate disposed in the inlet below the float, the plate including an opening through which fluid and air can pass.

16. In a fuel-water separator having a housing, a plurality of spaces within the housing through which fuel and water can flow, and an air-restrictive element which restricts air passage between at least one space upstream of the air-restrictive element and at least one space downstream of the air-restrictive element, the improvement comprising a vent for venting air which collects in a space upstream of the air barrier, the vent comprising:
an inlet means disposed in the upstream space, a float, buoyant with respect to fuel and water, disposed in the inlet, a passageway leading from the inlet means for directing air from the inlet, a seat for engaging the float, the seat being above the float, the engagement of the seat to the float causing the passageway to become closed.

17. The improvement of claim 16, further comprising an outlet to which air is directed from the inlet, and wherein the outlet opens into a space in the separator downstream of the air-restrictive element.