Fuel filter assembly with flow restriction sleeve

A “no filter, no run” filtration system that is designed to verify that an appropriate filter cartridge is installed. A flow control sleeve is provided on a standpipe to control the flow of fluid, for example fuel, into the standpipe. The sleeve can be axially moveable between closed and open positions, with one or more members on an installed filter cartridge designed to release the sleeve to permit the movement from the closed position to the open position to allow fluid flow. A spring acts on the sleeve to bias the sleeve back to the closed position upon removal of the filter cartridge. The sleeve can also be designed without axial movement, but nonetheless is configured to be opened and closed to control fluid flow into the standpipe.

FIELD

This disclosure generally pertains to the field of filtration, and more particularly to fuel filtration systems designed to safe-guard against damage to fuel injectors, associated fuel components, and engine malfunctions resulting from a missing or incorrect fuel filter.

BACKGROUND

Fuel filtration systems are known that are designed to prevent flow of fuel to an engine if no filter cartridge is installed or in the incorrect filter cartridge is installed. In these “no filter, no run” systems, not only must a filter cartridge be present, but the correct filter cartridge must be used, in order to allow fuel to flow to the engine.

In some fuel filtration systems that use a filter cartridge, whether in a “no filter, no run” system or not, removal and servicing of the filter cartridge can be difficult. Therefore, a fuel filtration system that enhances filter cartridge removal and servicing would be beneficial.

SUMMARY

A “no filter, no run” filtration system that is designed to verify that a filter cartridge is present to safe-guard against damage to fuel injectors, associated fuel components, etc. and engine malfunctions. Fuel flow to the engine is substantially prevented if a filter cartridge is not installed, and an appropriately designed filter cartridge is required to be used in order to permit sufficient fuel flow.

A flow control sleeve is provided on a standpipe to control the flow of fuel into the standpipe. The sleeve can be axially moveable between closed and open positions, with one or more members on an installed filter cartridge designed to release the sleeve to permit the movement from the closed position to the open position to allow fuel flow. A spring acts on the sleeve to bias the sleeve back to the closed position upon removal of the filter cartridge. The bias of the spring also creates a positive force that acts on the filter cartridge in the removal direction through the sleeve thus facilitating a more effortless cartridge removal. The sleeve can also be designed without axial movement, but nonetheless is configured to be opened and closed to control fuel flow into the standpipe.

In one embodiment, a filter housing includes a standpipe and a flow control sleeve surrounds at least a portion of the standpipe. The sleeve includes at least one opening through the sleeve, and the sleeve is slideably disposed on the standpipe for movement between a first position where the sleeve covers the standpipe opening and a second position where the sleeve opening is at least partially aligned with the standpipe opening. When the standpipe opening is covered, fuel is substantially prevented from flowing into and through the standpipe, thereby preventing engine operation. When the sleeve opening and the standpipe opening align, fuel can flow into and through the standpipe and ultimately to the engine. To actuate the sleeve to the second position, an appropriately designed filter cartridge must be installed in the filter housing.

In another embodiment, a filter housing includes a standpipe with a standpipe opening and a sleeve surrounds at least a portion of the standpipe including the standpipe opening. The sleeve includes a plurality of resilient fingers that are deflectable from a first position to a second position. The standpipe opening is covered when the fingers are in the first position to prevent flow through the standpipe and the standpipe opening is not covered when the fingers are at the second position to permit flow through the standpipe.

The fingers can close and open the standpipe opening without axial movement of the sleeve, in which case deflection of the fingers to the second position uncovers the standpipe opening sufficiently to allow fuel to flow through gaps created between the fingers and into the standpipe opening. Alternatively, the sleeve can be designed to move axially to control flow through the standpipe opening, with the deflection of the fingers controlling axial movement of the sleeve.

The fingers are deflected by one or more protrusions on a filter cartridge that is installed. In one embodiment, the protrusions can remain engaged with the fingers at the second position and retain the fingers under load at the second position when the standpipe opening is not covered. In another embodiment, a tapered recess, slot or groove can be incorporated on the standpipe to unload the fingers until the cartridge is removed and the bias spring resets the sleeve.

When the sleeve is designed to move axially, a spring can be provided that biases the sleeve to a closed position. Since the sleeve is engaged with the filter cartridge, the spring also facilitates removal of the filter cartridge by applying a bias to the filter cartridge to lift the cartridge upward in a cartridge removal direction. This facilitates removal of the cartridge from the filter housing.

In certain designs, the flow control sleeve can be designed to permit a certain amount of fuel flow past the sleeve and into the standpipe. The amount of fuel flow permitted when the sleeve is closed should be insufficient to operate the engine. In some designs, the sleeve can be manufactured to less exacting tolerances since it need not completely shut off fuel flow, thereby reducing the cost of manufacture of the sleeve. In other designs, the sleeve and/or standpipe can be manufactured with features to permit flow. Nonetheless, the amount of fuel flow permitted when the sleeve is closed is low enough that engine operation is prevented.

DETAILED DESCRIPTION

FIG. 1illustrates a filter assembly10, for example a fuel filter assembly, which is intended to filter a fluid, for example fuel, prior to the fluid reaching an engine. The assembly10includes a filter housing12that is designed to receive a filter cartridge14therein for filtering the fluid. The description will hereinafter refer to the filter assembly10as being a fuel filter assembly, and that the fluid being filtered is fuel. However, in appropriate circumstances, the concepts described herein can be applied to other types of filter assemblies that filter other types of fluids.

The filter housing12includes a housing body that has a side wall16and an end wall18. The side wall16and the end wall18define a filter cartridge space20that is large enough to receive the filter cartridge14therein, with the end wall18forming a closed end of the space20. The housing body has an open end22generally opposite the end wall18, with the open end22in use being closed by a cap (not shown) that closes off the space20. The housing body also includes an inlet opening24, illustrated inFIG. 1as extending through the side wall16, through which fuel to be filtered enters the space20, and an outlet26, illustrated as extending from the end wall18through which fuel exits on its way to the engine. It is to be realized that the filter housing12could have other configurations than that described herein.

A standpipe30is secured to the end wall18and extends upwardly into the space20toward the open end22. In the illustrated embodiment, the standpipe30is generally hollow from its end32connected to the end wall18to a tip end34thereof, thereby defining an internal flow passage36. The flow passage36is in communication with the outlet26so that fuel that enters the standpipe30can flow from the standpipe and into the outlet26to the engine. The standpipe30is disposed generally centrally in the housing12, with a central axis A-A of the standpipe30generally coaxial with a central axis of the space20.

In the embodiment illustrated inFIG. 1, the standpipe30is generally cylindrical and the passage36is generally circular along its length when the standpipe30is viewed in a cross-section taken perpendicular to the axis A-A. However, the standpipe30and the passage36could have other configurations, such as non-cylindrical and non-circular. For example, the passage36could be oval in cross-section.

The standpipe30is stepped in diameter to define different diameter sections40a,40b,40c. The section40aextends from the end wall18for the majority of the length of the standpipe30. The section40b, which has a smaller diameter than the section40a, extends upwardly from the section40a. A shoulder42is defined at the juncture of the sections40a,40b. The section40c, which has a smaller diameter than the section40b, extends upwardly from the section40band includes the tip end34. A shoulder44is defined at the juncture of the sections40b,40c.

A flow control sleeve50is slideably disposed on the standpipe30adjacent the tip end34. With reference toFIGS. 2-5, the sleeve50comprises a generally circular body52having a first section54with one or more slots56extending through the body52and a second section55with one or more flow openings57. As shown inFIG. 2, the openings57are positioned at circumferential locations on the sleeve50between the slots56. The sleeve50is made of a material suitable for exposure to fuel or other type of fluid flowing through the assembly10. For example, the sleeve50can be made of plastic or metal.

A plurality of resilient fingers58are secured to the upper section54and extend into the body52. The fingers58are integrally formed with the body52, and are thus made of the same material as the body52. The fingers58extend from their point of attachment to the body52downward into the interior of the body spaced from the interior surface of the body52. As shown inFIG. 3, the fingers58decrease in width (i.e. taper) as they extend from their attachment point to the body to unattached, distal ends60which are spaced from the distal ends of adjacent fingers58. As shown inFIG. 1, the fingers58also normally angle toward each other and the central axis A-A, with the distal ends60defining an opening.

Due to their construction, the ends60of the fingers58are resilient and can be deflected generally radially outward to the position shown inFIG. 3upon application of a suitable force to actuation surfaces thereof that face generally inwardly toward the central axis A-A. Upon removal of that force, the fingers58automatically return to their position shown inFIG. 1.

With reference toFIGS. 1 and 3, the section40cof the standpipe30includes a circular support shoulder62at the tip end34on which the distal ends60are received at the closed position of the sleeve50. A coil spring64extends between the shoulder44and the interior of the sleeve50where the fingers58connect to the body52. The spring64biases the sleeve50in a direction away from the end wall18, i.e. in a direction opposite an insertion direction of the filter cartridge into the housing. Small protrusions66on the outside of the standpipe30engage within the slots56in the sleeve50to limit axial movement of the sleeve toward and away from the end wall18as well as limiting rotational movement of the sleeve50.

One or more openings70are formed in the section40bof the standpipe30to place the exterior of the standpipe in communication with the passage36. In the illustrated embodiment, the number of openings70corresponds to the number of openings57formed in the sleeve50. However, a larger or smaller number of openings70can be provided. The openings70are positioned at circumferential positions that correspond to the openings57, without overlapping the slots56. Therefore, fluid is prevented from flowing through the slots56and into the openings70.

The sleeve50is configured such that at the closed position shown inFIG. 1, the first section54of the sleeve covers the openings70, to thereby prevent fuel from entering into the standpipe30. Upon movement of the sleeve to the open position shown inFIG. 3, the openings57in the sleeve align with the openings70to permit fuel to flow into the standpipe.

Movement of the sleeve50to the open position occurs as a result of installing the correct filter cartridge14. Returning toFIG. 1, the cartridge14includes a ring of filter media80suitable for filtering fuel. The outside of the filter media80defines a dirty or unfiltered fuel side while inside the ring of media80is a clean or filtered fuel side. Thus, the filter cartridge is configured for outside-in flow.

A first end cap or plate82is secured to the bottom end of the media80for generally closing the bottom end of the media. The plate82includes an opening84therethrough through which the standpipe is inserted upon installation of the filter cartridge. A seal (not shown) will typically be provided on the plate82to seal with the standpipe30to prevent leakage of clean fuel past the plate82. A second end cap or plate86is secured to the opposite end of the media80for closing off the opposite end of the media.

In the illustrated embodiment, the plate86is generally flat and planar. Except that the plate86includes a projection90that projects along the axis A-A downwardly into the interior space of the media80. The projection90is designed to actuate the fingers58and deflect them radially to release the fingers from the shoulder62and permit axial movement of the sleeve. The projection90is wider than the section40cof the standpipe so that the fingers58are deflected outward a sufficient distance to clear the shoulder62.

As illustrated inFIGS. 1 and 3, the projection90is designed to extend into the end of the sleeve50and engage the fingers58when the filter cartridge14is installed. As the projection90travels downward, the projection deflects the fingers58radially outward, which disengages the ends60of the fingers from the shoulder62. This permits the weight of the filter cartridge14acting on the top end of the sleeve50and the force from the person installing the filter cartridge14to force the sleeve50downward until the ends60of the fingers engage the shoulder44. At this position, the openings57will be aligned with the openings70to permit fuel to enter into the standpipe.

In the illustrated embodiment, when the sleeve50is open, the projection90remains in contact with the fingers58and keeps the fingers58under load. In an alternative embodiment, a tapered recess, slot or groove can be provided on the standpipe30to unload the fingers58when the sleeve50is open. The recess, slot or groove would allow release of the fingers therefrom when the cartridge is removed and the bias spring64resets the sleeve50.

Upon removal of the filter cartridge14, the spring64will bias the sleeve50upward to the position shown inFIG. 1, thereby preventing fuel flow into the standpipe until the correct filter cartridge with a protrusion that can release the fingers is installed. If a standard filter cartridge without a suitable protrusion is installed, the sleeve will not slide down the standpipe, and the filter cartridge will project upward from the housing12and prevent installation of the housing cover. This will act as a sign that the incorrect filter cartridge has been installed.

With reference toFIGS. 6-8, an alternative embodiment of a flow control sleeve100is illustrated. The sleeve100is slideably disposed on a standpipe102that includes an opening104into the interior of the standpipe.

The sleeve100includes a generally circular body with a solid section108and an upper section with one or more openings110extending through the body106. A plurality of resilient fingers112extend upwardly from an upper end114of the body106, with a shoulder116defined between the fingers112and the end114. A coil spring118is disposed within the sleeve100, engaged between the shoulder116and a shoulder120on the standpipe102. The spring118biases the sleeve100upwardly away from an end wall of the housing containing the standpipe to a closed position shown inFIGS. 6 and 7.

The fingers112comprise a plurality of fingers disposed at spaced locations around the sleeve100. Upper ends122of the fingers flare outwardly, and each finger112includes a protrusion124projecting inwardly at the base of the flared end122. The protrusions124engage with a shoulder126defined on the standpipe102to prevent downward axial sliding movement of the sleeve100and retain the sleeve at a closed position. At the closed position, the solid section108covers the standpipe opening104to prevent fuel flow into the standpipe.

However, the fingers112are deflectable generally outward in a radial direction as a result of a force being applied to the flared ends122. When deflected outward, the engagement between the protrusions124and the shoulder126is released, allowing the sleeve to slide axially downward to an open position as shown inFIG. 8. In the open position, the opening110in the sleeve aligns with the standpipe opening104to permit fuel flow into the standpipe.

Deflection of the fingers112is caused by suitable structure on an upper end plate130of a filter cartridge when the filter cartridge is installed. Only the end plate130of the filter cartridge is illustrated inFIGS. 7 and 8, the remainder of the filter cartridge not being important to describing the operation of the sleeve100. The end plate130includes a circular protrusion132that projects downwardly therefrom. The protrusion132includes a central recess134that receives the end of the standpipe when the cartridge is installed, a projecting rim136surrounding the recess134, a radial surface138, and an axial surface140. The rim136includes an angled surface142that extends from the radial surface138.

With reference toFIG. 7, when the filter cartridge is installed, the angled surface142of the protrusion132engages the flared ends122of the fingers112, which causes the ends of the fingers112to deflect outwardly. This deflection releases the protrusions124and the shoulder126, thereby permitting the sleeve100to slide downward. As shown inFIG. 8, the sleeve100is pushed downward against the bias of the spring118, eventually reaching the point where the openings104,110are aligned.

When the sleeve100is open, the protrusion132remains in contact with the fingers112and keeps the fingers112under load. However, a tapered recess, slot or groove can be provided on the standpipe that receives the protrusions124to unload the fingers112when the sleeve100is open.

Upon removal of the filter cartridge, the spring118will bias the sleeve100upward to the position shown inFIG. 7, thereby preventing fuel flow into the standpipe until the correct filter cartridge with a protrusion that can release the fingers is installed. If a standard filter cartridge without a suitable protrusion is installed, the sleeve will not slide down the standpipe, and the filter cartridge will project upward from the filter housing and prevent installation of the housing cover. This will act as a sign that the incorrect filter cartridge has been installed.

Another alternative embodiment of a flow control sleeve200is illustrated inFIGS. 9 and 10. The sleeve200is slideably disposed on a standpipe202that includes an opening204into the interior of the standpipe. In this embodiment, the sleeve200includes resilient, deflectable fingers206extending upwardly from the end of the sleeve200. The fingers206include protrusions208that engage within a recess or recesses210in the outside surface of the standpipe to retain the sleeve200at a closed position where the sleeve200prevents fuel flow into the standpipe opening204. The fingers206must be deflected outwardly to release the engagement between the protrusions208and the recess210to allow the sleeve200to slide downward in an axial direction.

Deflection of the fingers206is caused by a protrusion220formed on an upper end plate222of a filter cartridge. The protrusion220includes a central recess224that receives the end of the standpipe and a similar rim structure226as the rim described inFIGS. 6-8. With reference toFIGS. 9 and 10, when the filter cartridge is installed, the rim structure226of the protrusion220engages the ends of the fingers206, deflecting the fingers outwardly to release the protrusions208from the recess210. The sleeve200can then slide down to align an opening in the sleeve with the standpipe opening204.

Upon removal of the filter cartridge, a coil spring230biases the sleeve200upwardly until the protrusions208engage within the recess210, thereby locking the sleeve at the closed position.

FIG. 11illustrates an embodiment of a sleeve300that slides axially and which is similar to the sleeve200inFIGS. 9 and 10, but the sleeve does not include an opening that aligns with a standpipe opening302. Instead, deflection of fingers304allows the sleeve to slide downward. Gaps306between the fingers304permits fuel to flow into the standpipe opening302through the gaps306between the fingers304. A coil spring308biases the sleeve300back to the closed position upon removal of the filter cartridge.

In an embodiment somewhat similar toFIG. 11, a sleeve can be designed without axial movement, but where fingers deflect outwardly to uncover a standpipe opening that is covered by the fingers which are relatively closely spaced together. When the fingers deflect outwardly, gaps created between the fingers allow fuel to flow into the standpipe opening. When the filter cartridge is removed, the fingers deflect back to their closed position covering the standpipe opening to prevent fuel flow into the standpipe. Since the sleeve does not move axially, a biasing spring is not required in this embodiment.

In all of the embodiments described herein, the sleeves have been described as preventing fuel flow into the standpipe when the sleeve is at a closed position. However, it is contemplated that the embodiments described herein could be designed to permit a certain amount of fuel to flow into the standpipe when the sleeve is at the closed position. The amount of fuel permitted to flow when the sleeve is closed should be insufficient to permit engine operation. This permits the sleeves described herein to be manufactured to less exacting tolerances since they would not need to completely shut off fuel flow. This would permit reduction in the cost of manufacture of the sleeve, since it need not fit closely onto the standpipe. Alternatively, the sleeve and/or standpipe can be manufactured with features to permit fuel to flow into the standpipe when the sleeve is closed. For example, grooves or channels could be provided on the sleeve and/or standpipe to permit limited fuel flow when the sleeve is at the closed position. Therefore, the word prevention of fuel flow (or similar) as used herein, unless indicated otherwise, is meant to include complete shut off of fuel, as well as allowing limited flow of fuel as long as the amount of fuel is insufficient to permit engine operation.