Abstract: A filter unit formed by spirally winding a multi-layer material around a core to form a generally cylindrical construction having two opposing spiral end surfaces. The multilayer material has at least two filter layers and at least two spacer layers formed from a material with a high void volume. The multi-layer material need not include a fluid-impermeable layer. The layers are arranged and adhered along the lengthwise and widthwise edges so that, in use, unfiltered fluid passing through one spiral surface of the filter unit into one spacer layer must pass through a filter layer prior to passing out of the construction through the opposing spiral end surface.

Abstract: A clarification tank having a plurality of pick-up trays and a central collection column which is connected to an externally located riser having a high volume discharge weir at the upper end thereof. The tank also includes a plurality of sand pan draw-offs connected to a collection piping system which permits gathering material from all of the sand pan drains in a single discharge line by static pressure differential.

Abstract: A support structure for a pleated filter element is moulded of nylon and has parallel spaced bars joined at one face by the bases of frusto-conical fingers moulded integrally therewith. During manufacture of the element, the rows of fingers are engaged in the pleats of pleated filter medium from a pleating machine and the assembly is then curved into cylindrical shape.

Abstract: The fluid to be treated is directed along a main flow path and past a flow-off edge on the concave side of the main flow path to produce a stationary whirl at least contacting the main fluid flow and in which suspended matter is separated from the fluid, by centrifugal force, to provide purified fluid. At selected locations in the stationary whirl, a selected one of the purified fluid and the suspended matter is separated and withdrawn from the stationary whirl. The non-separated portion of the fluid volume, whose suspended matter content is now changed, is returned into the main flow. The geometric form of the whirl axis is selected in accordance with the particular requirements of each installation. Thus, starting from a simple cylindrical configuration, the whirl may take any form having a curvilinear axis, even an annular form with a circular axis.

Abstract: A method and apparatus are provided for separating oily particles from an emulsion thereof in an aqueous liquid. The emulsion is passed through a bed of oleophilic granules supported on a foraminous support, the oleophilic granules, by virtue of their density, pressing against the foraminous support and the bed is unconfined downstream thereof so that the granules in the bed are fluidized by the passage of liquid therethrough. The oily particles are removed from the emulsion by the oleophilic granules in the bed, and the oily material accumulates and agglomerates and is transported out of the bed by the passage of liquid therethrough. The movement of the liquid then carries the oily droplets which are formed in the bed and deposits them upon a screen positioned downstream of the bed, the aqueous liquid passing through the screen in purified form. The oil accumulates on the screen and is propelled by the moving liquid into an oil reservoir positioned downstream of the screen.

Abstract: A method and apparatus are provided for separating fine oily particles from aqueous liquids at very high flow velocities by passing the mixture upwardly through an unconfined mass of oleophilic granules in a column with adequate velocity to separate and lift the individual granules into the upwardly flowing mixture within the column where movement of the individual granules serves to collect and coalesce the fine oily particles, and finally to release large oil drops back into the mainstream of the upwardly flowing mixture column. These large oil drops are then intercepted and extracted by a steeply inclined screen and caused to flow to storage in the form of a fine oil film propelled by the force of the flow of the aqueous liquid through the screen.

Abstract: A liquid filter comprises an open cell, elastomeric foam body and a dimensionally stable gate. The foam body is formed with a central opening that defines an inlet surface through which a liquid to be filtered enters. The periphery of the foam body defines an outlet surface through which the filtered liquid exits.

Abstract: A device for the preparation of filtered coffee is described. It has a permanent filter disk which can be reused, thus eliminating the need for frequent replacement.

Abstract: A grit selector having an upper settling chamber and a lower grit storage chamber. The settling chamber communicates with the storage chamber through a relatively small opening in a flat transition surface therebetween. Rotating paddles critically positioned within the settling chamber cause the flow of liquid entering the settling chamber adjacent the outer periphery to rotate about the chamber in a forced vortex having upward spiral flow. Settled grit attaches to the transition surface at the settling chamber perimeter before one revolution. The spiral flow urges the grit across the transition surface towards the opening while the organics are lifted upward and back into the flow. The grit drops through the opening into the grit storage chamber and the organics are carried out of the settling chamber through an outlet passageway.

Abstract: Separating and thickening apparatus, particularly advantageous for use in processing pulp, characterized by an apertured duct preferably of U-shape and rectangular cross-section. The duct is distinguished by closely spaced walls and incorporates removable screen segments which are readily accessible and easily replaced. The apparatus is so contrived to enable a highly efficient, high capacity, dewatering or thickening structure which requires no moving parts.

Abstract: A filter medium which permits an increased amount of filtration. The filter medium can be prepared by blending 100 parts by weight of aggregate particles, 5-18 parts by weight of an inorganic bonding material having a chemical composition of about 10-50% by weight of SiO.sub.2 and about 5-20% by weight of B.sub.2 O.sub.3 and containing at least 70% by weight of a non-vitreous substance such as talc or boric acid, and about 3-15 parts by weight of a combustible substance such as wheat flour, kneading the mixture with a caking material and water, molding the kneaded mixture, drying it, and then calcining the dried mixture at a temperature not lower than about 1100.degree.C. The size and number of the air-permeable pores in the filter medium can be controlled by adjusting the amounts of the bonding material and combustible substance.

Abstract: A reusable coffee filter with a pot-shaped hotwater container and a filter strainer adjacent an opening in the bottom of said container. The filter strainer is made of metallic sieve sheets having perforations flaring out in the flow direction. On top of the hotwater container a distribution plate is supportably held which has a plurality of holes distributed over an area corresponding to the vertical projection of the opening of the filter strainer in order to ensure a good wetting and extraction efficiency of the coffee powder.

Abstract: A fibre-containing liquid is sprayed on the inlet side of a first strainer, there being a flow path for medium passing therethrough and leading from the outlet side of the strainer. A second strainer spaced from the first strainer covers said flow path and has mesh openings larger than those of the first strainer but small enough so that fibres passing through the first strainer, due to rupture thereof, will rapidly obstruct the second strainer.

Abstract: An apparatus for effecting purification and fractional separation of a material suspension, which includes a screening assembly of the closed centripetal type comprising an outer annular chamber with a stationary outer shell and also an inward rotatable drum, together with an inner annular chamber which is radially outwardly defined by said first drum and radially inwardly by a second screening drum, an improvement in the efficiency of the separatory apparatus consists in providing means for creating pulsating waves in the suspension in association with said first rotating screening drum.

Abstract: Sewage sludge of a uniformly high solids content is pumped from a primary settling tank to a digester or thickener by an air operated spring assisted diaphragm pump.