Abstract: An air duct block for air/water underdrain systems in gravity filters comprising a row of interconnected air duct blocks positioned below the filtering media and extending transversely to the underdrain laterals. Each air duct block is in communication with at least one adjacent individual underdrain filter block to supply backwash gas thereto during backwashing operations, thereby supplying backwash gas to its associated lateral. Each air duct block is in further communication with at least one adjacent air duct block such that backwash gas flows between the interconnected air duct blocks and along the row of air duct blocks. This system supplies backwash gas to the entire underdrain system through a single pipe from a source of supply.

Abstract: Improved methods are disclosed for cleansing a plurality of seriate filter beds in automatic backwash filtering systems by backwashing the beds one at a time with backwash liquid from an effluent channel common to seriate effluent ports of the plurality of filter beds and pumping the backwash liquid seriatim through separate effluent ports of individual filter beds and then flowing filtered effluent from each bed through its effluent port into the effluent channel, repeating such steps of backwashing and flowing filtered effluent on individual filter beds until all the filter beds in the system have been backwashed wherein, simultaneously with the backwashing of a second bed, waste liquid from the first bed is pumped through its port while the waste liquid is monitored for turbidity and such waste liquid pumping is continued until the turbidity thereof reaches a predetermined low level.

Abstract: A multiple tank filtration system can be backflushed to remove the material on the loaded adsorbent at a high rate of liquid flow through the use of a tank connecting distributor which has pervious projections extending therefrom into both the first and second tanks. The pervious projections extending into the first tank are less than those which extend into the second tank. This provides for a greater flow of liquid during backwash.

Abstract: Declining rate filtration systems using influent siphoning for influent flow to a bed of particulate filter media are improved by using at least two influent siphons with each filter bed. In use of such improved systems, influent is siphoned from a flume source or the like to the filter bed after backwashing of the filter media through a first siphon and, thereafter as headloss in the filter bed increases, further influent from the source is siphoned to the filter bed through a second siphon that has an effective minimum cross-sectional area substantially greater than that of the first siphon.

Abstract: Method for purifying a liquid from solid and liquid impurities by flotation-filtration in which the dirt flocks in the liquid to be purified are separated from the liquid to be purified after which they are led to the top of the liquid to form a sludge bed 16 from there to continue out to a sludge canal 17 and to a drain. The purified liquid flows further through a sand filter 18 to an isolated space 20 under the filter, through filter nozzles 19 and from there further through a pipe system 23, to, for example, a pure water reservoir. The filter is washed in an upstream direction by an opposite water flow. The sludge canal which also works as a rinsing water canal (17) or only as a rinsing water canal and the rinsing water canal (22) are placed on different sides of the filtration apparatus and only the canal that works as a rinsing water canal (22) is situated behind the separation canal (12) which means that the rinsing water has to flow over the separation canal (12).

Abstract: A method and apparatus for filtering a fluid through a particulate filter medium and for periodically scrubbing the particulate filter medium of accumulated contaminating material. During the filtration cycle, the particulate filter medium is retained with a filtration vessel by a bottom screen. During the scrubbing cycle, the particulate filter medium is retained within the filtration vessel by the bottom screen and a top screen. The combined surface area of the bottom screen and the top screen is substantially greater than the surface area of the bottom screen alone. During the scrubbing cycle, the particulate filter medium is fluidized with a scrubbing fluid and violently circulated to remove accumulated contaminating material from the filter medium, thereby suspending the contaminating material in the fluidized mixture.

Abstract: A method of repurifying water from a public supply, comprising the steps of:taking water to be repurified continuously from the public supply;filtering the water slowly through a volume of particulate material; andaccumulating the filtered water to provide a store of repurified water for later use as and when required.According to a second aspect of the present invention, there is provided an apparatus for repurifying water from a public supply, comprising:a water inlet adapted for connection to the public supply and operable to take a continuous flow of water from the supply;a filter comprising a volume of particulate filter material and arranged to receive the water from the water inlet;a container arranged to receive filtered water therefrom and to store the filtered water;and a water outlet connected to the container and operable to draw off filtered water as and when required.

Abstract: A filter block having a plurality of exterior and interior walls defining a plurality of interior chambers, said chambers including at least a first and second conduits parallel to the longitudinal axis of said block, one disposed above the other, with a third conduit provided to supply gas under pressure to the upper conduit; a top exterior wall of the block having a plurality of apertures distributed thereover. The interior chambers comprise separate conduits for both gas and liquid backwash flows. The interior walls defining the conduits are disposed to provide even distribution of the backwashing gas and to provide bearing support for the top wall of the block.

Abstract: An improved apparatus and method for operating a granular medium filter is disclosed. The apparatus comprises an improved underdrain structure made up of a plurality of rectangular compartments which allows the filter bed to be "air pulsed" as well as backwashed for thorough cleaning of the bed. Nozzles are positioned within the rectangular compartments and directed vertically into the filter bed. Fluid from the nozzles helps to break up the bed during backwashing as well as countereact size classification of the medium during this process. The method of operating a filter with the improved underdrain structure is also described.

Abstract: An improved apparatus and process for the operation of a down-flow granular medium bed filter is disclosed. A splash plate for dissipating the force of influent liquid is rotatably connected to support means, allowing the plate to rotate from a position parallel to the bed surface to a position perpendicular to the bed surface upon the liquid above the bed rising to a selected first level. The splash plate is maintained in the perpendicular position for the remainder of the filtration cycle, the backwash cycle and any chemical cleaning cycle, allowing unobstructed operation of the filter bed. The splash plate returns to the original position at the start of another filtration cycle.

Abstract: Disclosed are method and apparatus for filtering particles and gels from cellulose ester dope by passing the dope in plug flow through a tubular filter so as to cause particles and gels to migrate towards the center of the stream and shear forces along the filter walls to reduce the viscosity so that the boundary layer will exude through the filter walls. The concentrate containing the particles and gels is thereby separated from the filtrate.

Abstract: The invention concerns a method of and a plant for purifying water in an open, solid filter bed (17) in which, after the addition of chemicals, the water to be purified is passed through a filter bed, said filter bed being regenerated by counter-flow flushing, wherein the water to be purified in the filter bed is caused by force to flow through the bed at a constant rate by means of a partial vacuum created by a pump means (20) arranged downstream the bed (17), the flow being kept constant with the aid of a control valve (23) arranged on the pressure side of the pump (20).

Abstract: A granular media filter has an underdrain system for use in a granular media filter comprising perforated lateral conduits arranged for the distribution of air and water for scouring and backwashing of the filter. Each conduit is in the form of a single linear conduit containing two or more separate axially parallel ducts, each duct having an external wall in common with the conduit, which wall is provided with axially spaced apertures for emission of water or air, there being no intercommunication between the ducts. The underdrain system itself also forms a feature of the invention.

Abstract: A method of repurifying water from a public supply, comprising the steps of:taking water to be repurified continuously from the public supply;filtering the water slowly through a volume of particulate material; andaccumulating the filtered water to provide a store of repurified water for later use as and when required.According to a second aspect of the present invention, there is provided an apparatus for repurifying water from a public supply, comprising:a water inlet adapted for connection to the public supply and operable to take a continuous flow of water from the supply;a filer comprising a volume of particulate filter material and arranged to receive the water from the water inlet;a container arranged to receive filtered water therefrom and to store the filtered water;and a water outlet connected to the container and operable to draw off filtered water as and when required.

Abstract: A multi-bed filtration system includes an upstream filter bed in series with a downstream filter bed of nonbuoyant media. Also included is a system for periodically backwashing the nonbuoyant filter bed. Coagulant-treated water is passed through the upstream filter bed, followed by the downward flow of water through the downstream filter bed. Thereafter, the downward flow of water through the downstream filter bed is periodically interrupted. During these interruptions, a limited amount of water is introduced upwardly through the downstream filter bed by the backwashing system. Such backwashing frees coagulated solids within the bed, causing the solids to move upwardly through the bed. The solids ultimately collect in a zone above the surface of the bed. When normal filtration recommences, water passes through the deck of solids in the zone prior to entering the nonbuoyant filter bed.

Abstract: A method for dewatering slurry product streams of a corn wet milling process is disclosed. The dewatering process uses an automatic pressure filter to perform the dewatering. The filter is operated at 4 to 20 bars pressure for about 5 to 25 minutes. Such filter is shown to have an improved efficiency over conventional mechanical filtering devices.

Abstract: There is provided an improved method of cleansing a filter bed utilizing a backwash pump (12) having an inlet line (14) and an outlet line (16). The improved method and system includes two cycle operations. Initially, the filter bed is backwashed to remove contaminants from the filter bed with the backwash pump (12) drawing liquid from an effluent channel (32) through a first diverter valve (18). The fluid flows through a second diverter valve (20) and a first throttling control valve (36) for insert into a backwash shoe (38). In the purging cycle, fluid may be recirculated from the backwash pump (12) through the backwash shoe (38) and then back to the backwash pump (12) with a portion of the fluid being diverted through a second diverter valve (20') into an egress line (42).

Abstract: A liquid purification system using buoyant filter media for removing suspended solids from liquid comprising a vessel having a wastewater inlet and a clarified effluent outlet. Baffles are provided in the vessel to define an upflow region for the wastewaters over a weir into a downflow region for subsequent removal by the effluent outlet. Buoyant media is provided in the upflow and downflow regions where the buoyancy of the media in the upflow region carries some of the buoyant media over into the downflow region until equilibrium is reached. A device may be provided for the continuous removal, washing and return of buoyant media to the system.

Abstract: The present invention provides a rotary drum filter wherein one or preferably two rotary drum filters are submerged in a tank of liquid to be filtered. Each rotary drum filter is comprised of a generally cylindrical tank having a perforated outer wall plate over which is applied a cloth type filter media. A suction pipe is included inside the rotary drum filter so that filtered liquid can be drawn into the rotary drum filter through the pressure differential established by the suction pipe. Clean filtered liquid exits the suction pipe to the industrial apparatus with which the filter apparatus is used. A backwash vacuum box extending generally the length of the rotary drum filter media is in contact with a portion of the rotary drum filter media. A partial vacuum is established in the vacuum box such that filtered liquid can be drawn outwardly from the rotary drum filter such that solids accumulated on the filter media are drawn off from the filter media thereby cleaning that section of the filter media.

Abstract: A process and system are provided for treating fluid. In one illustrative embodiment, the treatment comprises the recharging of a resin bed in a water softener. A flow switch and accumulating timer are actuated when a selected flow rate is detected. The accumulating timer is set to a selected elapsed time. A chronological timer is also provided and is set for a selected time of day to recharge the resin bed. A reserve brine capacity is provided by delivering a selected amount of water to a brine tank at predetermined elapsed time intervals of the accumulating timer. The resin bed is recharged when both a selected elapsed time of the accumulating timer has occurred and it is the selected time of day.

Abstract: The present invention relates to an improved water filter which comprises a cone-shaped tank, a filtering bed layer, four conduits provided in the tank and concealed in the filtering bed and a four-way valve provided on the outer wall of the tank at the junction of the conduits which allows passage between any two adjacent conduits by means of a moveable plug operated in a predetermined turn so that the filtering and backwashing process of the tank can be easily controlled by the valve in practical use and the filtering bed is prevented from boiling and cracks along the side walls of the tank.

Abstract: A deep bed filter of the type comprising an upright vessel of particulate filter medium, inlet means at the top of the vessel for introduction of an aqueous stream to be filtered, outlet means at the bottom for removal of filtered liquid and means for backwashing the medium by an upward flow of liquid, has as the filter medium bone char and sand, the bone char being located substantially above the sand. The sand generally comprises a particulate mineral filter material selected from silica sand, fused alumina, garnet, zircon, ilmenite and glass.

Abstract: Improved open gravity backwash filters have a filter chamber containing a particulate filter bed with drainage space beneath the bed and an effluent channel into which filtered effluent from the drainage space flows at a limited rate during the filter mode of operation. The effluent channel has an outflow weir at a height above the top of the filter bed. There is an influent channel in which the influent liquid level is above the top of the filter bed, a gullet with a floor below the top of the filter bed to receive influent from the influent channel and a waste effluent channel with a floor below the level of the top of the filter bed. During the filtering mode, influent is siphoned from the influent channel into the gullet from where it flows to and through the filter bed.

Abstract: Filter apparatus embodying a filter bed back-washing unit comprising a raisable and lowerable suction bell, the side walls of which define division walls to compart the respective partial volume of the filter bed to be cleaned. The side walls of the suction bell are of a height at least equal to the height of the filter bed, and the suction bell is raisable and lowerable by a stroke length which corresponds at least approximately to this height.

Abstract: This invention relates to a backwash outlet assembly for a liquid particulate filter. The outlet is adapted to retain particles which comprise the filter medium while allowing backwash liquid together with impurities to discharge to waste. The outlet comprises an outlet weir, and a substantially non-turbulent flow zone located upstream of the weir. A particle return passage extends from the floor of the zone to the filter bed and means are included to at least restrict back flow in the passage. Filter media particles carried in suspension in the backwash liquid fall under the action of gravity to the floor of the zone and by the velocity of the backwash liquid into the entrance to the return passage. Preferably the particle return passage extends from the zone adjacent the weir and filter media particles trapped in the return passage are automatically conveyed back to the filter.

Abstract: A polymer slurry is passed past a filter and a wash fluid is caused to flow at a substantial angle with respect to the flow of the polymer slurry and toward the filter such as to replace at least a substantial portion of the fluid of the polymer slurry.

Abstract: An assembly for mounting a pH probe in a flowing solution, such as a sanitary sewer line, which prevents the sensitive glass portion of the probe from becoming coated with grease, oil, and other contaminants, whereby the probe gives reliable pH indication over an extended period of time. The pH probe assembly utilizes a special filter media and a timed back-rinse feature for flushing clear surface contaminants of the filter. The flushing liquid is of a known pH and is utilized to check performance of the probe.

Abstract: Apparatus and a method for removing suspended particles from water in a circular tank having a distribution and flocculation chamber immersed in the tank of water and carried circularly around the tank by a carriage. Flocculating material and inlet water are introduced into the body of water from the moving flocculating chamber at the same rate as clarified water is discharged through a filter substantially covering the bottom of the tank. A majority of particles in the water is collected by flocs in the water and floated to the water surface by air bubble action. The floating sludge is removed by a spiral scoop carried by the carriage. The water is then passed through the bottom filter which removes the remaining flocs completing the clarification of the water for discharge. Apparatus is provided for selectively back washing sections of the filter while the remainder of the filter is in operation.

Abstract: A hydrophilic oleophobic filter medium in granular form and composed of glass beads dispersed in a matrix of cured cement. The granules may be utilized in conjunction with naturally occurring materials, e.g., sand and/or anthracite. The granular density can be predetermined and varied. The granular shape is regular and controllable and the granular size can be graded for each density, so that the granules in a given filter level are of varient size, having a uniformity coefficient ranging from about 1.2 to 1.7. The method of making such granules includes the steps of casting a sheet of desired density and thickness, partially curing the sheet, severing the partially cured sheet to polygonal granules, curing the granules, optionally tumbling the granules, and finally screening them for final sizing.

Abstract: A filter regeneration method comprising mixing precipitate deposited on a bed of filtering particles throughout the bed to thereby reduce the pressure drop across the filter generally occurring during use. Regeneration is conveniently accomplished by fluidizing the precipitate and filtering particles into another portion of the filter. Two types of apparatus are described in which the regeneration method may be used.

Abstract: There is described a device comprising a filtering compartment enclosing a filtering body, an inlet for unfiltered water and an outlet for filtered water, said inlet being preceded by a liquid-receiving compartment which communicates with a container containing a sterilizing product at a level lower than the highest permissible water level inside said receiving compartment and above the filtered water outlet level.

Abstract: A filtration system includes a deep-bed type filter to receive an inflow of a waste water when the system is in a filtration mode. A distribution plenum within the filter distributes the waste water to an upper and lower portion of the filter bed. As the waste water flows to conduits centrally located within the bed, particulate in the waste water is entrapped by filter media comprising the bed. The waste water is discharged from the system in a clarified condition. Periodically the system is placed in a rejuvenation mode wherein a series of circuits are used to remove the entrapped particulate from the filter bed so that the system may again be returned to its filtration mode to process additional waste water.

Abstract: Liquid effluent from a conventional septic tank is passed successively through a filter tank and a plurality of spaced ozonating tanks, at least one of which has an activated charcoal filter located intermediate its ends. The filtered liquid passes from the last ozonating tank into a reservoir, and finally through an overflow outlet to a surrounding leach field. Perforated diffusers in the lower ends of the ozonating tanks are connected to an ozone generator which intermittently supplies ozone gas to the diffusers. Excess ozone gas is piped from the upper ends of the ozonating tanks back to the septic tank to increase the effectiveness of the septic tank. Dimethyl sulfoxide is added to the septic tank to prevent sludge formation.

Abstract: In the particular embodiment of the invention described in the specification, a liquid to be purified passes first through a screen, a sand trap, a first sedimentation basin, an aeration basin and a second sedimentation basin, and then through a final purification step for chemical admixture and passage upwardly through a particulate filter bed. The particulate filter material is circulated continuously from the bottom of the filter bed through a washing device and the cleaned particulate material is deposited at the top of the filter bed. Sludge collected from the sedimentation basins and the washing device is treated in thickeners and digesters.

Abstract: A water treatment device of the type which automatically regenerates itself at predetermined intervals is provided with a special disinfectant feeder device which dispenses a predetermined amount of disinfectant into the water treating media bed and the device itself to kill the bacteria therein. The disinfectant is dispensed at a predetermined time during the regeneration cycle so that subsequent to its bactericidal action all traces of the disinfectant will be flushed from the treatment device prior to the completion of the regeneration cycle.