SE437017B - Clarifying device. - Google Patents

Abstract

The invention is a purification device of the type in which active flock is bonded to flock-bearing particles and contains a vertical, cylindrical vessel (12) with a bottom (14) and a side wall (16), a filter bed zone (33) of flock-bearing particles, intake body for the suspension (80, 81) at the lower part of the vessel, outlet body (70) for outfeed of released filter material, outlet body (60) for purified water, a level control body located at the upper part of the vessel (12), a circulation body (83) for the suspension and fibre material and an air and polymer supply body (84, 85). The device also contains a conical, perforated outlet plate (40) located below the intake body (80, 81) for the suspension and the upper outlet body for the purified water (60). An upper (37) and lower (30) partition, mounted coaxially to one another and at a distance from one another and from the side wall of the vessel (16), form a ring-shaped chamber between the side wall and partitions whereby the lower end (31) of the lower partition (30) is at a distance above the perforated outlet plate (40). The ring-shaped chamber (35) has a purification zone (35A) at the bottom, a return zone in the middle (35B) and a separation zone (35C) at the top. In the return zone (35B), the two partitions (30, 37) are at a distance from one another to produce a connection from the outer ring-shaped chamber (35) in to the filter bed zone (33). The circulation body for the suspension is in the form of a perforated ring-shaped distribution pipe (83) at the lower part (35A) of the ring-shaped chamber between the side wall (16) and the lower part of the lower partition (30), whereby the intake body (80, 81) for the suspension and the supply body for air (85) are connected to the distribution pipe.<IMAGE>

Description

The inflowing liquid has a very small amount of suspended solid particles. Distinctive disadvantages accompany the use of sand filters. Usually such sand filters are a batch process that must be stopped and cleaned periodically. The pressure required to cause a current to flow through the unit increases over time due to the continuous build-up of solid particles in the sand bed. Clean water is required for proper cleaning, which is usually performed by backwashing. The use of a sand filter is very sensitive to the formation of sludge accumulations that can reduce the capacity of the sand filter unit. Sand filters usually have poor polyelectrolytic efficiency as many places Ét.ex. places where solids can get stuck) are never used and are not reached during cleaning or rinsing.

Such a device is often channeled depending on the mixture of the media (when several media are required). Large intermittent flush volumes are required and large intermittent air volumes are required during the cleaning procedure. Such large volumes increase energy consumption and operating costs.

Sand filters are usually limited by a very limited capacity for the treatment of suspended solids such as, for example, an inflow maximum of twenty to thirty ppm.

Upstream-type sand filters usually have the same disadvantages as downstream-type sand filters, possibly with the exception of the need for clean water to perform proper cleaning, and the electrolytic efficiency is slightly greater than that of downstream-type sand filters.

A tightly compressed media bed is necessary for efficient filtration of cloudy fluids. Such a tightly compressed media bed is obtained in many cases by using a downstream direction. Effective media cleaning is obtained by simultaneous aeration and flushing in an upward direction in such an amount that the medium is fluidized evenly. A desirable property is to be able to rinse with cloudy water at a minimal rinsing speed.

U.S. Patent 4,126,546 discloses a continuous upstream filtration method.

U.S. Patent 2,057,887 discloses a clarifier.

U.S. Patent 3,395,099 discloses a method and means for backwash cleaning of mineral beds.

U.S. Patent 3,537,582 discloses a liquid filter container 50 azozaoz-using sand.

U.S. Patent 3,581,895 discloses a filter system with automatic backwash cleaning for swimming pools.

A fluidized bed device for treating fluids is disclosed in U.S. Patent 3,667,604.

A method and apparatus for ultrasonically clear liquids is disclosed in U.S. Patent 3,707,230.

A sink filter with automatic backwash cleaning is disclosed in U.S. Patent 3,841,485.

Many of these devices have the disadvantage that they primarily take care of the backwash cleaning of the filter bed instead of a continuous cleaning and filtration.

Other such devices which attempt to provide continuous cleaning and filtration have the disadvantage that the continuous filtration is either ineffective or that the apparatus ceases to operate when the flow current increases.

Some devices are of the upstream type which may lose efficiency during cold periods of cold water as the viscosity increases and thereby improves the possibility of fluidizing the bed.

Other devices use only a small part of the flow through the unit to clean the dirtiest part of the filtrate medium or sand or the like.

The present invention provides an apparatus for continuously clearing and continuously flushing the flock carrier particles upon dynamic clarification of turbid fluids.

The present invention provides a clarifying device comprising a preferably cylindrical vessel having a bottom portion and an upwardly extending continuous side wall forming therein a liquid-containing space. An outlet for clean water is provided and an inlet allows the introduction of the turbid stream to be cleared.

A vertically extending partition, mainly concentric with the side wall of the tank, forms an annular surface and the surface with the movable bed. An aerator located within the ring provides aeration to bubble air upward into the vessel ring as during continuous flushing of the movable bed. The annular surface provides a lower cleaning zone, an intermediate return zone and an upper separation zone. A pump created in part by the aeration transports the lowest and dirtiest part of the moving bed into the annular cleaning zone where it is lifted into it and cleaned. In the cleaning zone, the flock carrier particles of the medium are cleaned and expanded to clean the movable bed. As the flock carrier particles rise, with individual particles now free of flock, they enter the return zone where they are directed back to the compressed part of the moving bed, while concentrated liberated flock enters the separation zone for disposal.

With the present invention, PH control is not required. Furthermore, the present invention does not increase the amount of loose solid particles entering the stream to be treated.

The present invention provides a clarifying device which recovers quickly in the event of malfunction. This period of rapid recovery will normally be the time required for the volume of a volume after corrective action has been taken, and may e.g. be in the order of ten minutes. This fast recovery could make the difference of keeping a special device in operation.

The clarification device according to the invention is less sensitive to temperature and suspended solid particles. It has no internal moving parts that wear or work poorly.

The clarification device according to the invention requires only ten to fifteen percent of the area required by a conventional clarification device. The sludge produced is easily dewatered.

The clarification device according to the invention is a continuous process and is continuously flushed during operation. The unit's pressure requirements are lower and constant rather than the pressure build-up that occurs in sand filters of the usual type. Unclear water can be used for flushing, so no storage space is needed for flushing water. The formation of sludge clumps is not a problem and there is a high polyelectrolytic efficiency due to recirculation of the sludge. A single medium is all that is required for the operation of the clarification device.

The clarification device according to the invention provides a small separation volume and a continuous low volume of air.

According to the invention, there is provided a clarifying device which can treat inflowing liquids with a high concentration of suspended solid particles of up-til, e.g. five hundred ppm. It is an object of the invention to provide a device with the advantages of a high rinsing speed but low separation speed.

It is thus an object of the invention to provide a clarifying device for use with liquids which has a high efficiency flushing using a high flushing rate with the turbid incoming stream as flushing water which incoming stream of flushing water is then finally clarified.

Another object of the invention is to provide a clarification device with intimate contact between the inflowing water which has unflocked particles and activated sludge in order to achieve a very efficient flocculation condition before clarification.

Another object of the invention is to provide a clarifying device using a non-batch process in which continuous rinsing is achieved.

Another object of the invention is to provide a clarification device in which continuous clarification is achieved.

Another object of the invention is to provide a clarification device with a simplified control system.

Yet another object of the invention is to provide a clarification device which is easy to operate, easy to manufacture and easy to maintain.

For a further understanding of the character and features of the invention, reference is made to the following detailed description and to the accompanying drawings. Fig. 1 shows a partially cut away perspective view of a preferred embodiment of the clarification device according to the invention, Fig. 2 a schematic section through the preferred embodiment of the clarification device according to the invention, Fig. 3 a section taken along lines 3-3 in Fig. 2. Fig. 4 is a partial perspective view of a second preferred embodiment of a part of the clarification device according to the invention and Figs. a detail according to another preferred embodiment.

Figs. 1 and Z best show the preferred embodiment of the clarification device 10 according to the invention. The clarification device 10 comprises a vessel 12 which has a bottom 14 which e.g. may be convex in shape as shown in the configuration of Figs. 1 and Z. The vessel 12 further has a side wall 16 which at the bottom edge 17 joins the bottom 14 in a sealing manner so as to allow a liquid to be trapped therein. in a liquid-containing space 18 defined as the area inside the side wall 16 and the bottom 14.

The side wall 16 extends upwards to the upper edge 19 which can form the upper surface of the clarifying device 10.

The vessel 12 thus comprises an inner space 18 which would normally contain a liquid such as water, if e.g. turbid water, would be cleared. A water surface WS is shown schematically in Fig. 1. Fig. 1 also shows a movable bed 20 which e.g. may be activated carbon, crushed walnut shells, sand or the like.

The movable bed 20 moves continuously during operation as indicated by the direction of flow arrows F in Fig. 2. The movable bed 20 occupies two main zones, the zone with the compressed bed 33 and an expanding zone in the ring 35. The movable bed the bed 20 may comprise a large number of individual flock carrier particles which are granular, and individual and thus movable inside the vessel 12. Each flock carrier particle is furthermore cleanable and has a large surface area, and a surface charge for attracting particles which can be removed from the incoming the current.

As described in more detail below, the clarification device 10 provides continuous clarification and continuous cleaning of the movable bed 20. A part of the movable bed 20 is compressed during operation. The compressed zone of the moving bed 20 is indicated by 33 and forms the part of the moving bed 20 through which the incoming stream passes for clarification, with individual particles of suspended solid particles and similar adhering to the flock material carried on the tightly packed flock carrier particles and taken thus away from the current being processed. The compressed zone 33 of the media bed 20 lies substantially inside the enclosure of the partition 30 and above a perforated outlet plate 40, and has an upper surface L. The lower part of the compressed media zone 33 is continuously removed therefrom while the medium is continuously returned to the compressed media bed zone 33. After being removed from the lower part of the compressed media zone 33, individual media flock carrier particles are continuously cleaned during expansion of the bed. During the cleaning of the bed, the entire incoming stream was used as rinsing water, while at the same time the still useful flocks; The particles carried on individual flock carrier particles now ready for cleaning pretreat the incoming sewage stream during this continuous cleaning / rinsing. Continuous rinsing / cleaning takes place in the ring, which is described in more detail below.

A lower partition wall 30 is arranged inside the space 18 and may suitably be concentric with the side wall 12.

The lower partition wall 30 terminates at its lower end part 31 at a small distance above the bottom 14 and the conical perforated outlet plate 40. At its upper edge 32 the lower partition wall 30 meets the zone 35B and may above it have a reduced diameter with the possible upper part with reduced diameter indicated by the reference numeral 37. The upper partition 37 may have a smaller diameter, and its lower edge 39 is also connected to the zone SSB.

The space between the partitions 30, 37 and the side wall 13 of the vessel forms therebetween the ring 35 which may have different diameters above and below a transition zone which forms a return zone SSB of the ring 35. The dimension line D1 in fig. 1 shows the possibly smaller thickness of the ring 35 at the bottom of the lower partition 30, while the dimension line D2 indicates a possibly increased thickness of the ring 35 at the upper partition 37.

The ring 35 is thus divided into three areas. These are indicated by the reference numerals 35A-35C, and denote a cleaning zone 35A, a return zone 35B and a separation zone SSC, respectively. In the cleaning zone 35A the bed is expanded and cleaned while in the return zone SSB the increased diameter of the ring 35 causes the individual particles to be returned to the compressed bed zone 33 as schematically shown by the arrows zoo in Fig. 1. made flock removed from the individual flock carrier zones. SSC carries the concentrated free particles during cleaning upwards to the outlet chute 70.

The outlet 60 for the discharge of clear water is located at the bottom 14 of the vessel 12 and below the perforated plate 40. Flushing outlet water is discharged through the upper channel 70 and thence through a V-shaped overflow opening 75. The level L of the filter medium 20 is mainly below the return zone 35B within the lower partition 30 which forms the media bed area. The compressed bed zone 33 normally contains compressed media that can handle fluids because the flow is downward toward the plate 40.

An inlet pipe 80 allows the introduction of a water flow to be cleared into the vessel 12 after passing through the control valve V which may be connected by a suitable instrument line 82 to level monitor LC which may vary the incoming flow through the pipe 80 according to the water level at the chute 70.

The incoming water through the pipe 80 can be introduced into the vessel 12 at the opening 81 and then to a distribution pipe 83 which may have a circular shape located at the bottom of the ring 35 and around the periphery of the vessel 12 adjacent the lower edge 31 of the partition 30. The inlet opening 81 may be connected to the circular tube 83 by means of a three-way connection, with suitable supports such as being welded, or the like to the wall 16.

-During operation, a polymer and air can be introduced, e.g. through conduits 84 and 85, respectively, into the tube 80 prior to insertion through the opening 81 into the circular manifold 83. Air at least partially supplies the movable force to move the movable bed 20 upwardly past the lower edge 31 of the partition 30 and into the ring 35 formed between the vessel wall 16 and the partition wall 30. Pick carrier particles entering the ring 35 at the cleaning zone 35A are thus separated and fluidized by the upstream of the ring 35. As the bed 20 rises above the upper surface of the wall 30 to the return zone 35B, the ring 35 increases cross-sectional area from dimension D1 to dimension D2 as shown in Fig. 1 and the speed decreases below the capture rate of the individual particles of the media bed and the flock carrier particles are therefore deposited on the surface of the media bed 20 inside the partition 30; (See arrows 200 in Figs. 1 and 2).

The velocity in the ring zone 35C of the ring 55 is still large enough to carry flock particles to the outlet chute 70. The water flow in the flushing outlet is controlled by the level monitor LC which sets a level through the V-shaped overflow opening 75 by controlling the inlet valve V.

The circular manifold 83 may be at a level horizontally level with the bottom 31 of the cylindrical partition 30. The circular manifold 83 may be provided with evenly distributed holes to allow inlet water, air and polymers to be injected into the ring 35 'in a evenly distributed pattern. The holes in the manifold 83 may face downward to minimize clogging of individual flock carrier particles. A diverter 88 may be located below the manifold 83 to prevent flow of the flow. The holes in the manifold 83 may be widened to allow debris to pass therethrough without clogging. The conical perforated outlet plate 40 may be located at the bottom 14 of the vessel 12, with a clearance between the bottom edge 31 of the partition 30 and the outlet plate 40.

Flushing outlet water is discharged through the gutter 70 and out through the V-shaped overflow opening 75 to the outlet pipe 76. In Figs. 1 and 2 a continuous nozzle is formed between the inwardly hanging plates 90, 91 attached to the upper and lower side wall, respectively. 30, 37. The plate 90 may be perforated.

Nozzles 50 (partially shown) connect to the skirt P which can connect between the upper surface of the lower partition 30 and the lower surface of the upper partition 37.

Figures 4 and 5 show alternative designs of the annular return zone 35B. In Fig. 5, a pair of nozzles 50 return individual flock carrier particles to the compressed zone 33 of the media bed. In fig. 4, a continuous flange (forming the upper surface 32 of the lower partition wall 30) is separated from the lower flange of the partition wall 37).

Claims (10)

szozunz-s w Patentkrav A clarification device of the type in which activated flock is attached to flock carrier particles comprising a vertical cylindrical vessel (12) with a bottom (14) and a side wall (16), a filter bed zone (33) of flock carrier particles, inlet means (80, 81) at the lower part of the vessel for a suspension, outlet means (70) for discharging released filter material, outlet means (60) for clarified water, a level regulating means located in an upper part of the vessel (12), circulation means (83 ) for the suspension and the filter material and air and polymer supply means (84, 85), characterized in that it further comprises a conical perforated outlet plate (40) located below the inlet means (80, 81) for the suspension and over the outlet means for clarified water (60 ), an upper (37) and a lower (30) partition wall mounted coaxially with each other and at some distance from each other and from the side wall (16) of the vessel forming an annular space between the side wall and the partitions and where the lower part the lower end (31) of the wedge wall (30) is at some distance above the perforated outlet plate (40), the annular space (35) at the bottom consisting of a cleaning zone (35A), in the middle of a return zone (35B) and at the top of a partition zone (35C), wherein in the return zone (3SB) the two partitions (30, 37) have the mutual distance from each other to effect a connection from the outer annular space (35) into the filter bed zone (33), and that the circulating means for the suspension is made in the form of a perforated annular distribution tube (83) located in the lower part (35A) of the annular space between the side wall (16) and the lower part of the lower part. the partition wall (30), the inlet means (80, 81) for the suspension and the supply means for air (85) being connected to the distribution pipe. Clarification device according to claim 1, characterized in that the upper partition wall (37) at its lower end (39) has an inwardly and downwardly sloping plate (91) and the lower partition wall (30) at its upper end (32) has a corresponding inwardly and downwardly inclined plate (90), so that the two plates (90, 91) between them form a return channel to the filter bed zone (33). Clarification device according to Claim 1 or 2, characterized in that the upper cylindrical partition (37) has a smaller diameter than the lower cylindrical partition (30). Clarification device according to one of the preceding claims, characterized in that the annular distribution pipe (83) is located next to the lower edge (31) of the lower cylindrical partition (30) so that suspension suspended through the distribution pipe (83) is mixed with a part of the filter bed material (33) inside the partition (30). Clarification device according to one of the preceding claims, characterized in that the bottom (14) is convex and that the outlet means (60) is an opening formed in the convex bottom. ' Clarification device according to one of the preceding claims, characterized in that the inlet means comprises a manifold (80) attached to the side wall (16) of the vessel and that an opening (81) is arranged in the side wall for connecting the manifold to the distribution pipe inside the vessel. (83), Clarification device according to one of the preceding claims, characterized in that the outlet means for released filter material comprises an overflow device (70) at the upper part of the vessel. Clarification device according to claim 7, characterized in that the overflow device (70) comprises a V-shaped overflow opening (75). Clarification device according to one of the preceding claims, characterized in that the filter material is activated carbon, sand or crushed walnut shells. Clarification device according to one of the preceding claims, characterized in that the distribution pipe (83) is provided with a plurality of different air blow-out openings.