A filter element for fluids, in particular for hydraulic fluid, has a foldable filter casing (10) with at least one filter layer (18, 20, 22, 24) extending between two end caps (26, 32). To vary in regions the thickness of the filter casing (10), the height (h.sub.1) of each filter fold (12, 44) increases from one end cap (26) to the other end cap (32). Alternatively, with the filter fold height (h.sub.1) being maintained, the outer diameter (40) of the filter casing (10) varies in the direction of one of the end caps (26, 32).

A magnetic particle carrier fluid recovery system includes at least one filter and a fluorescence reducer in fluid communication with contaminated magnetic particle carrier fluid. The filter(s) removes particulate matter less than 1 micron in size. The fluorescence reducer removes soluble fluorescent compounds from the carrier fluid causing background fluorescence contamination. A pump circulates the carrier fluid from a reservoir of contaminated fluid, through the system, and back to the reservoir. A cleaning loop runs the carrier fluid through the filter(s) and fluorescence reducer to remove contaminants to levels acceptable for new magnetic particle carrier fluid. A testing loop may be included that bypasses the filter(s) and fluorescence reducer. A valve may be actuated to toggle between the testing loop and cleaning loop for selective cleaning or use of the carrier fluid for MPI testing. The system may be integrated with an MPI station or may be independent and mobile.

A filter device provides for designs that permit variable levels of solid particle and water molecule removal. The filter device retains the particles and the water molecules in the filter medium when removed, thus avoiding the re-entry of the particles and water molecules when the power system has cooled down as is now likely in conventional filters currently in use. Further, the filter device traps the water molecules already present in the fluid being filtered (i.e., native water), as well as any moisture resulting from condensation that may be introduced into the lubrication system whenever it is opened.

A filter element has a preferably multilayer structure of a pleated filter medium (3) with a plurality of individual filter pleats (5, 7). Due to an alternating sequence of filter pleats (5) with a first pleat height (h1) and filter pleats (7) with a second pleat height (h2), more effective filter surfaces are available than with filter pleats with a uniform pleat height. Upon throughflow by a fluid to be filtered, a lower surface load for the filter medium (30 and lower passage speed of the fluid are present during filtration. A static loading of the filter medium (3) during operation of the filter is then reduced. A hydraulic circuit has such a filter element (1).

A filter element for filtering a fluid is provided with a filter bellows made of a filter medium folded along fold edges in a zigzag shape to form folds, wherein the folds extend between oppositely positioned end face edges of the filter bellows. The filter bellows defines a raw side and a clean side of the filter element, wherein a fluid to be filtered flows from the raw side to the clean side. The filter medium has faces that are flowed through by the fluid to be filtered. The filter medium is provided at least on one of the faces that are flowed through with beads extending transversely to the fold edges. In a proper operating state of the filter bellows, the beads effect a flow of at least a portion of the fluid to be filtered in a direction perpendicular to the fold edges.

A filter cartridge has a folded filter medium that is formed into a prism at least in regions and comprises two interconnected end folds, and which filter cartridge is constantly or cyclically subjected to stresses, specifically subjected to stresses from dedusting by means of pressure surges, is characterized in that the end folds overlap one another.

A filter element has a preferably multilayer structure of a pleated filter medium (3) with a plurality of individual filter pleats (5, 7). Due to an alternating sequence of filter pleats (5) with a first pleat height (h1) and filter pleats (7) with a second pleat height (h2), more effective filter surfaces are available than with filter pleats with a uniform pleat height. Upon throughflow by a fluid to be filtered, a lower surface load for the filter medium (30 and lower passage speed of the fluid are present during filtration. A static loading of the filter medium (3) during operation of the filter is then reduced. A hydraulic circuit has such a filter element (1).

A filter media in which larger corrugations are impressed or embossed onto media that has been previously corrugated with standard corrugations. This construction greatly increases the beam strength of a resulting pleat that allows the channels to remain open during processing into the pleated media, and prevents buckling of the media duping gathering on current pleating equipment. In addition, once the media is pleated, the larger corrugations or embossments, combined with the standard corrugations, create large channels for fluid flow from pleat tip to the base of the pleat.

There is disclosed an apparatus for storing organic materials, the apparatus including: a body having an opening for receiving the organic materials to be stored; an outlet formed in the body through which the organic materials are unloaded from the body; a cooling fluid circuit for circulating cooling fluid through the organic material collected by the hopper.

A filter assembly comprises a housing open at one end, a filter element therein, and a plate at the open end enclosing the filter element within the housing. The filter assembly further includes a fluid flow control assembly disposed between an end of the filter element and the plate. The fluid flow control assembly includes a check valve and a relief valve seat upon which the check valve abuts to prevent flow of fluid through a by-pass passage. The check valve is held in a sealed position against the relief valve seat by a biasing member retained by the relief valve seat. The force of the biasing member is overcome when pressure in the fluid acting upon the check valve reaches or exceeds a certain level, causing the check valve to move away from the relief valve seat, and permitting the fluid to flow through the relief valve assembly to an outlet opening of the filter assembly, bypassing the filter element of the filter assembly.