Donaldson Comapny, Inc.

Jack Stifelman

Patrick Fisher

John F Connelly

Jeff J Theisen

Enrico Greco

Johan Fobe

Angelo Schiavon

The filter head and filter housing define a liquid flow inlet path, a first liquid flow outlet path, and a second liquid flow outlet path. A filter media construction is positioned within the housing. The filter media construction, in combination with the housing, defines an unfiltered liquid volume, and a filtered liquid volume. A first liquid flow inlet path directs liquid from the liquid flow inlet to the unfiltered liquid volume. A first liquid flow outlet path directs liquid flow from the filtered liquid volume to the first liquid flow outlet. A second liquid flow outlet path directs liquid flow from the filtered liquid volume to the second liquid flow outlet. A first valve assembly selectively opens the second liquid flow path to passage of liquid therethrough in response to a first selected liquid pressure level within the filtered liquid volume. A second valve assembly comprises a first bypass valve assembly, and selectively directs fluid flow from the unfiltered liquid volume to the second liquid flow outlet, in response to a second selected liquid pressure level within the unfiltered liquid volume.

In-tank fluid filter with valve assembly

A filter head for use in cooperative engagement with an associated liquid filter comprises a block member having a bypass valve assembly, and a back pressure flow valve assembly. The block member defines an inlet port; an inlet channel positioned for fluid communication between the inlet port and the associated liquid filter; a first outlet port; a second outlet port; and an outlet channel positioned for fluid communication between the associated liquid filter and the first and second outlet ports. When in an open orientation, the bypass valve provides fluid communication between the inlet channel and the outlet channel. When in a closed orientation, the bypass valve blocks fluid communication between the inlet channel and the outlet channel. The back pressure flow valve assembly, when in an open orientation, provides fluid communication between the outlet channel and the second outlet port. When in a closed orientation, the back pressure flow valve assembly blocks fluid communication between the outlet channel and the second outlet port.

Spin-on filter assembly with valve arrangements

A high pressure spin-on filter is provided having a generally cylindrical filter housing with an open end and a closed end. A generally cylindrical filter element having a closed end and an open end is disposed within the housing. A multifunctional rigid cover is disposed in the open end of the housing and includes a circular rim member extending into the housing. The rim member has an axial bore extending through the rim member and defines an inner surface. The inner surface is partially threaded and further has a groove formed in the inner surface. A main seal is located in the groove of the rim member. The rigid cover further includes a circular hub member having an axial bore through the hub member concentric with the axial bore of the rim member. A plurality of ribs interconnect the rib member to the hub member and cooperate with the rib member and the hub member to define a plurality of openings between the rib member and the hub member. Structure is provided for mounting the cover to the filter housing. The threads and main seal permit threaded and sealing connection of the filter to a filter head assembly such that fluid is directed from the filter head assembly through the filter for filtering.

High pressure hydraulic spin-on filter

A filter head assembly includes a relief valve assembly therein, and is adapted for use in a spin-on filter or the like. When the relief valve assembly is in a closed mode of operation, fluid flow through the filter head, and an associated filter, results in conventional filtration. When the relief valve assembly is in open mode of operation, the filter is substantially bypassed permitting fluid to flow directly through the filter head, with filtration. The relief valve assembly includes a movable piston member therein, which opens and closes for the respective flow passage outwardly from a lateral takeoff port. Any substantial, undesirable, lateral forces acting upon a piston member may be substantially reduced by means of a lateral pressure release system provided according to the present invention. Generally, the lateral pressure-relief system comprises an annular recess formed in the piston member. The preferred piston member is cup-shaped and has an outer sidewall slide portion which forms a slip fit with a valve body relief valve. The preferred slide member includes groove means therein, facilitating movement. Also, preferably, a first end of the piston member includes an annular portion thereon providing an extension of a first end of the piston member to increase surface area against which fluid pressure may act.

Relief valve assembly; piston member from same and filter head assembly

A high-strength spin-on filter (10) of improved fatigue strength comprises a cylindrical housing (12), a unitary cover (28) and an internal filter element assembly (18). The open end of the housing (12) is folded inwardly over the periphery of the cover (28) and into deformable engagement with radial projections (54) thereon to secure the cover and housing against both relative rotation and separation without stress concentrations that would otherwise decrease fatigue life of the filter (10) in high-pressure pulsatile hydraulic systems.

High-strength filter with improved fatigue rating

The present invention is directed to a duplex filter apparatus which provides for a first primary filter path and a second path for secondary filtration. The first path includes a shutoff valve on one side of the primary filter and a check valve on the downstream side. The second path includes a regulating bypass valve on the upstream side of the secondary filter and a check valve on the downstream side. The regulating bypass valve gradually shifts fluid flow from the first path to the second path when differential pressure across the primary filter increases beyond a predetermined level. A reservoir return bypass valve directs fluid flow gradually from the secondary filter when differential pressure across the secondary filter increases beyond a predetermined level. Bleed valves are provided to relieve pressure on filter elements when the filter elements are isolated so that servicing may occur.

Duplex filter apparatus

A differential pressure switch is disclosed. The switch functions through a conductive path formed within the fluid of a single cavity of a housing having passages for communicating high and low pressure fluid to the cavity. The switch has a cantilevered post with movable conducting and nonconducting members mounted thereabout and being movable between conductive and nonconductive states according to the differential pressure within the cavity. One of the movable members provides sealing between the post and the cavity wall to separate the high and low pressure fluids.

Differential pressure switch

The specification discloses an improved high strength spin-on fluid filter (10) including a housing (12), cover (28) and filter element assembly (18). The cover (28) includes a hub (30), rim (34), and radial ribs (32) and is preferably formed as an integral unit. The open end of the housing (12) is folded inwardly and back on itself over the rim (34) to form a folded connection (47) between the cover (28) and housing. Spacers (52) are preferably utilized around the lower end of the filter element assembly (18) to assure pressure equalization thereacross.

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Bolivar, MO, United States of America

Jack Stifelman