KR100226187B1 - Apparatus for uniformly distributing gas and/or liquid in an underdrain lateral system - Google Patents

Abstract

Culvert's side tube systems that are particularly suitable as a substitute for gravity filters include scalloped side tubes 26 and 126 having top, winding wire, slotted screen surfaces 28. The screen surface directly supports and retains the filter intermediate particles 118 without the underlying gravel layer and is supported by the channeled rod member 34 welded with the wire 30. The web portion 36 of the channel-shaped rod member serves to simultaneously distribute air and water during the countercurrent washing, the total area of the upper channel gap 38 is small, and the total area of the lower channel gap 40 is larger than that of the side pipe. The plenum 56 is formed therein so that the air and water distribution penetrates the side tubes and is uniformly distributed even though the side tubes do not completely level. The distribution of air and water through the side tubes is further enhanced by the provision of perforated flow tubes 122 extending from each side tube to the header and mounting of the side tubes on the header 124 to form additional air plenums 135. Become uniform.

Description

Culvert distribution unit

1 is a partial perspective view of a partially cut away filter incorporating the drainage system of the present invention.

FIG. 2 shows a partially broken scallop-shaped lateral which clearly shows a preferred configuration for uniformly distributing air and water during backwashing of the filter shown in FIG. Perspective cut away view.

3 is a schematic side view showing a flow path taken by water and air during operation of the filter of FIG. 1 in a countercurrent wash operation.

4 is a partial side view showing a modification of the header member composed of a tube of a predetermined length formed in the concrete bottom of the filter.

FIG. 5 is a partial end view showing a header member formed of a flat plate at the top thereof, the sides and the bottom being formed by a drip tray integrally formed at the bottom of the filter.

6A and 6B are cross-sectional views of the side and top of the filter incorporating the fan-shaped transverse tube distribution member according to the present invention.

7 is a side cross-sectional view of a prior art filter incorporating a filter block element located below the filter media in the upper layer with gravel in the lower layer, with too much air in a relatively large diameter air / water hole located at the top of the filter block. Or a side cross-sectional view of the filter illustrating how those layers can be flipped as the water passes through.

FIG. 8 is a side cross-sectional view of a prior art filter incorporating relatively wide spaced nozzles as temporary bottom and dispensing members located below the gravel of the lower layer and filter media of the upper layer, with a relatively large diameter located at the top of the temporary bottom. Side cross-sectional view of a filter illustrating how their layers can be flipped when too much air or water passes through the water / air holes in the filter.

9 is a side cross-sectional view of a prior art filter incorporating a series of parallel perforated transverse tubes located below the gravel of the lower layer and the filter media of the upper layer as a dispensing member, with a relatively large position located on the surface of the perforated transverse tubes Side cross-sectional view of a filter illustrating how their layers can be flipped when too much air passes through a diameter water hole.

FIG. 10 is a schematic partial side view of the filter of FIG. 1 showing a state of uniformly dispensing water onto the medium during a countercurrent wash operation with water only.

FIG. 11 is a schematic partial side view of the filter of FIG. 1 showing the movement of alternating air and water upward into the medium during a countercurrent wash operation with water / air or air alone to cause recirculation of the medium.

FIG. 12 is a partial cross sectional view taken along line XII of FIG. 4 illustrating air plenum formed in both the transverse tube and header during an air / water backwash operation.

* Explanation of symbols for main parts of the drawings

10 dispensing device 18 medium holding unit

20: distribution member 22, 122: flow pipe

24, 124: header member 26, 126: tubular member

32: leg 34: flow distribution

38, 40: hole 54, 127: countercurrent washing liquid

56, 131: backwash gas 58, 158: distribution plenum

The present invention relates to the distribution of air or other gas in a liquid, more specifically in a gravity filter. The use of air to backwash the gravity filter has become common practice in the US water treatment industry. Meanwhile, in Europe, air backwashing has been in use for decades. Based on the experience of these European facilities, what water treatment engineers have learned is that by using air rather than water alone, filter paper can be cleaned more efficiently.

A typical countercurrent wash sequence using only water is to pass a high speed countercurrent through the filter paper for a relatively long time. Typical countercurrent wash flow rates are 15-20 GPM / ft ² (611-815 L / min · m 2), where GPM / ft ² is an abbreviation for gallons per minute per square foot, and L / min · m 2 litres per minute Abbreviation for per square meter. This is compared with a typical filtration flow rate (downward) of 3 to 5 GPM / ft ² (122 to 204 L / mim · m 2). The countercurrent wash is continued for 10-20 minutes daily or every other day, depending on the solids contained in the untreated water.

The countercurrent washing procedure is usually carried out in two basic forms: The first form is an abbreviation of approximately 2-4 SCFM / ft ² (37-73 SCMH / m 2) for about 5 minutes, where SCFM / ft ² is an abbreviation of standard cubic feet per minute per square foot, and SCMH / m 2 is standard cubic meters per hour per square meter). The countercurrent wash using air alone is followed by a countercurrent wash of water in a short time of about 5 minutes at a flow rate of about 15-20 GPM / ft ² (611-815 L / min · m 2) described above.

The second form is to perform a simultaneous air / water cycle between the individual air and water cycles described above. The flow rates for these simultaneous cycles are typically 2-4 SCFM / ft ² (37-73 SCMH / m 2) and 3-5 GPM / ft ² (122-204 L / min · m 2). This simultaneous flow cycle lasts about 5 minutes. When using the second form, the duration of the final cycle using water only can be shorter by about 5 minutes.

When using the second form described above, the total amount of water used for the countercurrent wash is calculated, using approximately 90-125 gallons / ft at 150-400 gallons / ft ² (6,100-16,300 l / m2) using a countercurrent wash cycle of water. ² (3,700 to 5,100 l / m 2), it can be seen that the amount of water used can be significantly reduced. In addition to this, the filter paper is generally well cleaned in combination with the air backwash, further extending the filter run time between the backwash. This prolongation of the use time further reduces the amount of pure water used for the countercurrent washing water. This process clearly has economic advantages and is becoming more common.

A common method for culvert design in Europe usually installs hundreds to thousands of individual direct holding filter nozzles on a temporary floor. This temporary bottom is located about 30 cm (12 inches) above the original filter bottom and provides a flow chamber to be collected during filtration and dispensed during a countercurrent wash. In such a system, water can be dispensed relatively easily by limiting the flow area through the junction between each nozzle and the bottom. Due to this flow area limitation, a pressure drop occurs that tends to flow water toward all nozzles instead of concentrating only a few nozzles. However, there are other design problems when trying to distribute air. The designers of these systems, which use air for backwashing, have found that air is less dense than water, resulting in very little pressure drop through nozzle connections designed to distribute water. Thus, the air introduced into such a system tends to exhaust all through several nozzles that are initially encountered. On the other hand, if the nozzle connection holes are sized to be small enough to uniformly distribute the air, the pressure drop encountered during the flow of water becomes unacceptably large. Therefore, a distribution means for pre-distributing the airflow is required.

Preliminary dispensing is usually performed by incorporating drop-tubes at the connection point of each nozzle. These tubes are about 15 cm (6 inches) long and have an open bottom. Their diameter is equal to the diameter of the connection point. These drop tubes have slots or a series of holes in their walls, which do not extend over the entire length to the nozzle, but form side holes starting at a defined height below the nozzle. This arrangement allows the formation of an air plenum that distributes air throughout the bottom of the temporary bottom before air begins to escape through the side holes of the descent tube. As more air is introduced into the system, the height of the air / water boundary continues to decrease until there is a balance between the flow of air entering the system and the flow of air entering all of the drop tubes. By using tubes of the type described above, simultaneous air / water distribution is possible because water can flow through the open ends of the descent tubes without collapsing the air plenum.

The system just described has the disadvantages of cost, the need to provide a structurally strong temporary floor, the ease of breakage of individual nozzles, usually made of plastic material, and the difficulty of replacing the system with existing header / tunnel-type filters. do.

Another method of injecting air into the filter is to install a separate air distribution system, such as a perforated tube header transverse tube. This method is very expensive and it is necessary to place the air distributor on a graded support gravel which is common to most filters. If such an air distributor is located under the gravel, it typically lifts the gravel layer and collapses, resulting in a shortened filter paper life.

Another method for distributing air is to incorporate a separate air distribution in a culvert tube in the form of a block. Since this structure is relatively complicated, the installation cost of the culvert becomes expensive. In addition, such structures require the use of gravel selected on the block. Gravel stability can be very well controlled by maintaining a limited amount of air flow, but in this structure, the gravel collapse still remains a problem.

An example of a structure according to the prior art is described in US Pat. No. US-A-801,810 in Parmalee's name, which discloses a single top for distributing air into a bed of coarse gravel. It has a small hole at the top of the level and a large hole at the bottom of a single level for dispensing water. US Pat. No. 4,214,992 is similar to Parram's patent in that there is an air hole at a single level, but does not seem to solve simultaneous air / water backwash. US-A-4,707,257 has air and water holes at the same height in the same chamber, thus making the unit sensitive to height. The unit incorporates a double plenum, with one air plenum located under the temporary floor and the other under a flat distribution plate containing a screen of small pieces supporting the filter media. U.S. Patents US-A-5,015,383 and US-A-5,118,419 show fan-shaped culvert transverse tubes comprising an inner distribution member in FIGS. 7 and 15, 16 and 17, have. The perforations provided in these internal distribution members are sized to match the flow of water, thus preventing uniform distribution of air if the transverse tubes are not completely flat. For example, the distribution pipes of FIGS. 15 and 16 have holes formed only in the lower surface thereof. This structure forms a plenum when air enters, but at the higher end of the transverse tube the air tends to flow all out of the hole.

The present invention does not require the use of a separate air distributor, but instead provides a means for performing air, water, and air / water backwash wash distribution in a culvert transverse tube system capable of introducing air at the culvert level. Another object of the present invention is to provide a culvert system that directly supports the media bag without the need for a gravel layer located below. It is a further object of the present invention to provide a transverse tube system in which an air plenum can be formed which ensures that the flow of water can be evenly distributed without excessive pressure loss. It is a further object of the present invention to provide a culvert transverse tube system capable of distributing air and water at the same time without excessive loss of pressure and without damaging either the uniform distribution of air or water flow.

The foregoing and other objects are achieved by the apparatus of the present invention, which is provided with a dispensing member comprising a non-planar porous media holding portion, the holding portion of the medium being subjected to countercurrent washing liquid and gas during the countercurrent washing operation. Having a total opening area per unit length of the dispensing member of a first predetermined size that can pass upward in a counter, wherein the dispensing member is connected to a source of countercurrent wash liquid and gas and in a normal to the axis of the dispensing member; Viewed from the cross section taken, it has an outer surface comprising a plurality of holes arranged at a plurality of vertical levels, which holes are used to collect the liquid filtrate penetrating downward in the porous medium holding part in a collecting manner, and countercurrent In the cleaning method, the countercurrent washing liquid and the countercurrent washing gas are simultaneously discharged downwardly from the holder. Suitable for both being in contact with the sieve, the plurality of holes having a second total opening area of a predetermined size per unit length of the distribution member that is significantly less than a first total opening area of a predetermined size per unit length of the porous media holding portion. The plurality of holes having a plurality of first upper holes spaced in size and spaced along the length of the dispensing member for discharging the countercurrent cleaning gas relatively uniformly, and for discharging the countercurrent washing liquid relatively uniformly. Disposed at a plurality of vertical levels consisting of a plurality of second lower holes spaced in size along the length, the plurality of first upper holes being open at a plurality of vertical levels, at least some of which are at the top of the outer surface; Extending downwards by a distance of at least 2.5 cm from said plurality of second lower holes at the bottom of said outer surface or Positioned above and the first upper hole of the plurality is characterized by having a total open area per unit length substantially less than the total open area per unit length of the plurality of second lower holes.

By forming and positioning various gas and liquid holes as described above, only a limited amount of gas can escape through the upper holes, so that residual gas is forced to form a plenum and distributed along the length of the distribution member.

By providing holes in multiple levels, as the height of the plenum increases, more backwash gas per unit length of the dispensing member can escape. As a result, the plenum is stabilized at a predetermined height depending on the total volume of the countercurrent washing gas flowing into the distribution member. The uniformity of the distribution depends on the total number of uncovered perforations per unit length of the dispensing member, and on much less height than that corresponding to the structure shown in US Pat. No. US-A-5,015,383.

By properly selecting the size of the holes and the spacing between the holes, a desired flow rate for the countercurrent wash gas and liquid can be obtained, with the result that the gas plenum is stabilized at a level higher than that of the larger liquid dispensing holes.

The plurality of first holes for the countercurrent wash gas are no greater than 90%, suitably 65% to 40%, optionally 50% to 40% of the total area per unit length of the plurality of second holes for the countercurrent wash liquid. It is desirable to have a total area per unit length of.

The total open area per unit length of the media holding portion of the distribution member is preferably at least twice the total area per unit length of the plurality of holes located in the plurality of vertical levels of the enclosed flow distribution, the enclosed flow distribution from this distribution. It is provided in a countercurrent washing manner to simultaneously release the countercurrent washing liquid and countercurrent washing gas outward.

Small holes are arranged at the top levels of the internal flow distribution, and large holes are preferably arranged at the bottom of the distribution, but include, for example, the hole size of the step change from the very small size of the top to the very large size of the bottom. It is also possible to use other arrangements. However, it should be noted that the size of each hole is not important, but the total open area per unit length is important. Therefore, a limited open area can be achieved by making the number of holes the same but making the diameter smaller, or by making the hole diameter the same but reducing the number.

Now, the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, a filter assembly is indicated by reference numeral 10. This filter comprises a concrete floor 14 and a side wall 12, which is typically made of concrete. A drain drip 16 is mounted at a spaced point along the top of the filter for dispensing the untreated water and liquid to the filter, where the liquid passes down through the media 18 during collection to Collected by the dispensing member 20. It is preferable that the upper surface of this distribution member is porous and has a through-hole such as a thin slot that is sized to hold the particles constituting the medium bag 18. The distribution member 20 is shown as a transverse tube of fan-shaped cross section, but may also be of any tubular shape, including for example cylindrical. During the countercurrent washing system, the drainage catcher 16 collects the water which is directed upward through the media bag by the distribution member 20 and discards the water. The downwardly extending flow tube 22 is preferably mounted to each dispensing member and includes a plurality of holes 23 through which the water can flow to the header member 24. The header member is shown in the form of a drip tray formed in the bottom 14 covered with a plate 24 '. The plate 24 'is held in sealed relation to the drip tray by a sealing strip 25 of elastomer, which is disposed in the recess 14' under each edge thereof, so that it is held at the bottom by a bolt (not shown). Is fastened. The distribution member 20 is held by a pair of cramp rods 21 fastened to the bottom 14 by bolts 21 '. Although the holes 23 of the flow tube are shown as a series of holes spaced in the vertical direction, the holes can be described more precisely as opening means extending in the vertical direction, for example in other forms such as one or more vertical slots. Can be taken.

2 shows a preferred configuration of the dispensing member 20 in the form of a fan-shaped transverse tube member 26. The curved upper surface 28 of the member 26 surrounds a channel-shaped rod member 34 arranged cylindrically with a wire 30 having a wedge-shaped cross section, which is disclosed in US Pat. No. 4,096,911. As such, a curved screen formed by welding the wire to the legs 32 extending radially outward of the channel at all intersections of the wire is preferred. The channel members 34 comprise a web portion 36, some of which may be left blank depending on the intended operating state, or holes of various sizes may be provided at points spaced along their length. have. In order to optimally distribute the air and water during the countercurrent wash, and to provide a distributor that is relatively insensitive to small fluctuations in the vertical position from one end to the other, the channels located at several upper vertical levels may be A small hole 38 is formed which is particularly suitable for passing air during / water backwash operation. Similarly, one or more channels at the lower level are formed with large holes 40 suitable for water to pass through. The bottom of the transverse tube is shown as covered with an unperforated flat base plate 42 which generates all inflows and outflows of the distributor through the slot holes 44 between the wires 30. In order to achieve the desired flow during the countercurrent wash, the total area of the slot holes 44 is substantially larger than the total areas of the channel holes 38 and 40. When the lower part inside the traverse tube is filled with water 54 and the upper part is filled with air 56, during the backwash operation, the distributor air plenum 58 causes the top of the traverse tube and the surface level of the water 54 ( Between 60). The transverse tube is mounted 30 cm (12 inches) above the center with respect to the header, has a width of about 28 cm (11 inches) and a height of about 75 to 100 mm (3 to 4 inches), so that the It is desirable to size the area of the upper and lower level holes 38 and 40 so that the plenum 56 is at least 25 mm (1 inch) high. It is also desirable to extend the small upper level hole 38 at least somewhat below the level 60 of the air / water interface. Although the holes 38 and 40 have been described as small and large, the most important factor is that the total area of the upper hole 38 per unit length is considerably smaller than the total area of the lower hole 40 per unit length, which is This is because the area required to receive a given flow is much smaller than the area required to receive a given flow of water. Clearly, if the upper holes are spaced farther from each other than the lower holes in their respective channels, or if some of the upper channels do not contain any holes, all holes 38 and 40 can be the same size. have. However, in order to achieve uniform distribution along the length of the transverse tube, it is desirable to use different pore sizes. In addition, although the holes 38 and 40 are shown as forming rows spaced perpendicularly to one another, the required hole area is another method, such as using vertical slots with vertical slot portions that are open at a plurality of vertical levels. You can get For example, the dispensing member 20 may consist of a tube made of an elastic material having a series of thin slots into the surface around its periphery to provide air and water to the required flow area.

FIG. 3 shows the side wall 112, the base or bottom 114, the drain drip 116, the media bag 118, the flow tube 122 with the holes 123, as shown more clearly in FIG. Backflow cleaning operation in filter 110 with cylindrical header member 124 embedded in bottom 114 and fan-shaped transverse tube 126 is illustrated. During the countercurrent wash operation, water 127 is injected into the water conduit 129 under pressure and enters the hollow tubular header 124 with the air 131 injected into the air conduit 133. The restricted area of the flow tube aperture 123 is the air in the header plenum region 135 which ensures that the air 131 and water 127 flow into the various transverse tube elements 126 at a relatively constant flow rate along the length of the header. Cause to form. After the air and water enter the transverse tube, it passes upwards through the media stage 118, which stirs and fluidizes the media, resulting in dust or other particles 137 collected on the media stage particles during the collection cycle. In the final cleaning cycle, they are lifted up to the sump 116 for drainage which is carried and discarded by the conduit 139. Although the countercurrent washing operation has been described above, this operation is reversed and the collection operation is generally performed. For example, untreated water enters conduit 139 and flows to the surface of media bag 118 and passes through transverse tube element 126 through flow tube 122 to header 124. The water leaves the header through conduit 129. Although not shown, a dedicated valve can generate the flow of water and air as needed.

FIG. 4 shows an end view of the cylindrical header 124 with its side shown in FIG. 3, illustrating how the header is mounted to the flow tube 122 and the transverse tunnel 126. have. The flow pipe is provided with a flange portion 122 ′ positioned between the header flange portion 124 ′ and the bottom of the transverse tunnel tube 126. In order to seal the flow tube 122 to the transverse tube and the header, a mounting gasket 125 is preferably disposed below and above the flange portion 122 '.

FIG. 5 illustrates a drip-shaped header 24 of the type shown in FIG. 1 and has a recess 14 'for accommodating a cover plate 24' and a sealing strip 25 of elastomer. One filter bottom 14 is shown. The flow tube 22 is mounted to the transverse tunnel 26 in the manner shown in FIG.

Figures 6a to 9 illustrate the flow distribution system according to the invention in figure 6a, while Figures 7 to 9 show some prior art. 6a shows a filter 10 with a bottom 14 on which a fan-shaped transverse tube 26 is located. The positioned media zone 18 is supported by the transverse tunnel 26 and shows a dual media zone, for example comprising sand particles 50 at the lower level and coal particles 52 at the upper level. The media zone may also be a mixed media bed with three or four different types of particles at different levels. In three layers of media, the top layer is usually coal, the middle layer is silica sand, and the lower layer is garnet or ilmenite. These layers are small-density particles as they progress to the top layer, so that even if the media zone is agitated and circulated during the air / water backwash cycle, the particles originally loaded in the multiple layers return to their original layer during the final water only cycle. Tend to. 6b, similar to that of FIG. 6a, the dispensing member of the present invention can be anything other than a fan, and thus can be made as a cylindrical screen member 27. FIG. The conventional structures shown in FIGS. 7-9 have sufficiently large air / water or water outlet holes such that the presence of gravel layers 256,356,456 between the outlet holes and the media zones 218,318,418 is required. The gravel and media layers should be placed very carefully when initially loaded into the filter and collapse or flip over if the pressure and flow rate for the air and water injection are not very carefully controlled. As can be seen in FIGS. 7 to 9, the reversal moves the gravel upwards and allows the media to move downward to replace the displaced gravel. At this time, the medium may enter the dispensing member to block it, or make the filter inefficient by allowing too much water to escape the unit without being uniformly filtered in the inverted area. In addition, the medium may be lost, which may contaminate the collected water. The various filter arrangements shown include a block distributor 220 shown in filter 210 of FIG. 7, in which a large number of distributor blocks are disposed at the bottom 214 of the filter, so that the top surface of the block is located. Form a temporary floor supporting the gravel layer 256. Although this structure has a central, generally triangular tube section with holes at two levels where air plenums can form and allow air to escape at one level and water at another level, Air and water together leave the block through relatively large holes in the top of the block. 8 shows a filter 310 having a plurality of spaced dispensing lids or nozzles 320 mounted on a temporary bottom 358, which may form an air plenum below the temporary bottom. This structure requires a vertical space between the bottom of the filter 314 and the bottom of the media band 318, as shown in the block structure of FIG. To accommodate it requires a filter housing with a higher sidewall, or a lower height for a filter of the same size. FIG. 9 shows the scale slightly differently compared to other figures to more clearly illustrate the action that occurs during the rollover of the media as the gravel from the layer 456 moves to the top of the media 418. This is because the height of the medium stage 418 is very low compared to the distribution pipe 420. Dispensing pipe 420 is a system of typical water only, and since the distribution pipe 420 is relatively wide spaced, such as lid or nozzle 320 in FIG. Dead spots are formed between the distributors that cannot provide and that do not satisfactorily clean during the countercurrent wash. In addition, wide spacing becomes the media-to-part between dispensers that are not active during the collection mode.

10 and 11 illustrate the manner in which upward flow of countercurrent wash fluid occurs from the three transverse tube members 26. FIG. 10 shows the cycle to water only, where water moves upwards through all holes 38, 40 (second degree) as indicated by the down arrow, and relatively constant upwards as indicated by the upper arrow. To the media stage 18. FIG. 11 shows a combined cycle of air / water, in which a distribution air plenum 58 is formed, with the result that air is perpendicular from the upper aperture 38 (FIG. 2) to the media 18 as indicated by arrow A. FIG. On the other hand, the water moves upwards from the lower hole 40 (FIG. 2), as indicated by arrow W. Because air moves faster, the media particles move upwards to the area just above the transverse tunnel. Then, it causes the lowering to the area between the transverse tubes, which causes the circulation of the media particles as indicated by the upper arrow C.

FIG. 12 shows a double plenum formed during a countercurrent wash, which better distributes water and air in the header and transverse tube. The transverse tube 126 is attached to the header member 124 in the manner shown in FIG. 4 and is connected by a flow tube 122 having a hole 123. The hole 123 is made of a small enough area to generate back pressure that causes the compressed air 156 to forcibly lower the level of pressurized water 154 to form the header plenum 164. Air 156 moves upwards through the holes 123 and the flow tubes 122 to the transverse tube 126 and is accompanied by water 154 moving upwards through the bottom holes in each flow tube 122. Lower holes 40 (FIG. 2) to generate a distributor air plenum 158 that distributes air and water to the media stage 18 as shown in FIG. 11 when air and water are in the transverse tube. Large area of resistance and small area of upper hole 38 (Figure 2) resistance occur in water and air.

An example of a culvert transverse tube system made in accordance with the present invention is as follows. A series of fan-shaped transverse tubes 32, shown in FIG. 2, which are 325 cm (128 inches) long, are placed at the bottom of the filter, but are 30 cm (12 cm) from the center for a 50 cm (20 inch) header. Inches). The transverse tunnel consists of a mixed media bed consisting of approximately 15 cm (6 inches) bottom layer of fine sand, approximately 30 cm (12 inches) center layer of coarse sand, and approximately 45 cm (18 inches) top layer of coal. Placed on a filter on top of the. The fan-shaped part had an outer dimension consisting of a width of 27.3 cm (10.75 inches) x 10.7 cm (4.2 inches) and a slot width of 0.25 mm (0.010 inches), which was 2.36 mm (0.093) wide. Inches) provided about 10% open area. The total screen open area per length of 30 cm (12 inches) was 100 cm ² (16.0 in ² ). The 17 channels inside the screen included 13 at the top of the screen sized for air and 4 at the bottom sized for water. Each of the 13 upper channels is 2.38 mm (3 /) spaced above 10 cm (4 inches) from the center to provide a total air hole flow area of 1.96 cm ² (0.296 in ² ) per 30 cm (1 ft) in length. 32 inches) of holes. The four lower channels are 4.8 mm (3/16 inches) above 76 mm (3 inches) from the center to provide a total water hole flow area of 2.85 cm ² (0.442 in ² ) per 30 cm (1 ft) in length. A hole was included. 4 SCFM / ft (22.32 SCMH / m) of air flow in the transverse tube (equivalent to 4 SCFM / ft ² (73 SCMH / m²) in the media, since the transverse tube is located 30 cm (1 foot) from the center) And about 38 mm (1.5 inches) from the inner top of the transverse tube, or about 44 mm (1.75) from the bottom plate when 3 GPM / ft (122 l / min · m 2) of water flow in the transverse tube is injected into the transverse tube Air plenum extending above). Transverse tubes are 76 mm (3 inches) long and 33 cm (13 inches) long with four rows of 9.5 mm (3/8 inch) diameter holes vertically spaced 25 mm (1 inch) above the center in eight rows. It was connected to the header tube by a flow tube consisting of the tube. The total area of the holes in each flow tube is 22.8 cm ² (3.53 in ² ), approximately 35 cm (14 inches) at a flow rate of 1120 SCFM (1900 SCMH) for air and 840 GPM (3200 l / min) for water. This caused the header air plenum to occur at the water level. For the collection mode, the system was collected at about 4 GPM / ft ² (163 L / min · m 2), and the flow rate was 17 GPM / ft ² (693 L / min · m 2) for the countercurrent wash with water only.

Claims (14)

At least one elongated dispensing member 20 disposed generally horizontally below the granular media stage 18 which is periodically backwashed by the fluid, including the countercurrent wash liquid 54 and the countercurrent wash gas 56, Dispensing apparatus 10 for the culvert which generates a vertical plenum space of gas 58 over the liquid, the reflow washing liquid 54 and receiving means for receiving a pressurized countercurrent washing gas 56 in the liquid. The dispensing member 20 is formed of a predetermined size per unit length of the dispensing member through which the countercurrent washing liquid and the countercurrent washing gas can simultaneously pass upwardly into the medium stage 18 during the countercurrent washing operation. A non-planar porous media retainer 28 having a total open area, wherein the dispensing member 20 is connected to a source of backwash cleaning liquid 127 and backwash cleaning gas 131, and the axis of the distribution member. About In the collecting mode, the liquid filtrate passes downward through the porous medium holding unit 18 in the collecting mode, but the countercurrent washing liquid 54 and the countercurrent washing gas 56 in the countercurrent washing method. ) Further comprises an enclosed flow distribution 34 having an outer surface comprising a plurality of holes 38, 40 arranged at a plurality of vertical levels suitable for use in both simultaneously discharging outwards into contact with the medium. Wherein the plurality of holes 38, 40 have a second total open area of a predetermined size per unit length of the distribution member that is significantly less than a first total open area of a predetermined size per unit length of the porous media holding portion. And the plurality of holes 38, 40 disposed at the plurality of vertical levels are spaced along the length of the distribution member 20 for a relatively uniform discharge of the backwashing gas 56. A plurality of first upper holes 38 that are sized, and a plurality of second spaced apart sizes along the length of the dispensing member 20 for relatively uniform release of the backwashing liquid 54. A plurality of first upper holes 38, the plurality of first upper holes 38 being opened at a plurality of vertical levels, at least some of which are at least 2.5 cm away from the outer surface 28; Extending downwardly from an uppermost portion, the plurality of second lower holes 40 are disposed at at least one vertical level located at or above the bottom of the outer surface, the plurality of first upper holes 38 being the plurality of first lower holes 38. And a total open area per unit length of substantially less than the total open area per unit length of the second lower bore 40 of the dispensing device, wherein the dispensing device further comprises an unperforated base plate. 2. The porous media retainer 28 of the dispensing member 20 is a substantially tubular member 26, 27, 126 having an arcuate perforated surface portion 28, the surface portion of which is formed. Cavity dispensing device, characterized in that the hole (44) is made small enough to hold the granular medium. 3. The tubular member (26, 126) according to claim 2, having a substantially flat bottom surface (42) and a generally convexly curved upper surface (28) directly supporting the granular media (18, 118). Wherein the convexly curved upper surface (28) of the tubular member (26, 126) consists of a piece of slotted screen. 4. Dispensing device according to any one of the preceding claims, characterized in that the flow distribution part (34) of the dispensing member (20) is arranged inside the tubular member (26, 27, 126). 5. The flow distribution part 34 of the distribution member 20 has a substantially tubular cross section and is integrally attached to the inner wall portion 30 of the tubular members 26, 27, 126. Dispensing device of the culvert, characterized in that. The outer surface of the flow distribution part 34 of the distribution member 20 is an inner wall of the tubular member 26, 27, 126. Formed by the web portion 36 of a plurality of long and adjacent channeled members 34 having an outer radially extending leg portion 32 integrally attached to the 30, wherein the porous medium holding portion 28 has a hole 44 formed by a plurality of wires 30 parallel and closely spaced apart, and the leg 32 of the channel member 34 is welded to the wire to form the tubular shape. Dispensing device of the culvert, characterized in that the members (26, 27, 126) are configured to support the inner wall. 7. The at least a significant number of web portions 36 of the long, adjacent multiple channeled members 34 forming the outer surface of the flow distribution portion 34 of the distribution member 20 are spaced apart along their length. And a hole (38,40) disposed at a predetermined point, said hole consisting of said plurality of first upper holes (38) and a plurality of second lower holes (40). 8. The distribution member (20) according to any one of claims 1, 2, 3, 5, and 7, wherein the distribution member (20) is provided with a header member (via a communication port (22) through which fluid can pass). One of a number of transverse tube members 26,126 attached to 24,124, from which each of the transverse tube members 26,126 flows through the communication ports 22,122, the flow tube being the distribution member. Culvert distribution device, characterized in that extending from the inside of the flow distribution portion (34) of the (20) to the inside of the header member (24,124). 9. Dispensing device according to claim 8, characterized in that the flow conduit (22,122) comprises opening means (23,123) which open at the bottom and extend vertically on a side wall located inside the header member (24,124). 10. The hole according to any one of claims 1, 2, 3, 5, 7, and 9, wherein the plurality of first upper holes 38 are open at a plurality of vertical levels. And has a sufficiently small total area to apply back pressure to the backwash cleaning gas 131 injected into the distribution member, thereby causing the formation of the dispensing plenum 58, 158, which causes ) Is distributed evenly from one end of the dispensing member to the other end, and even if the dispensing member is not completely flat, the plurality of first upper holes 38 and the plurality of second lower The arrangement of the apertures 40 allows the countercurrent wash gas and liquid to be individually distributed at points horizontally spaced across the width of the flow distribution 34, thereby allowing the gas 131 and liquid 127 to be dispensed. Is spaced apart along the width of the distribution member 20 Dispensing device of the culvert, characterized by fluidizing the granular media zone (18,118) by flowing upward into the media layer. 11. The distribution member (20) of claim 10, wherein the distribution member (20) is one of a plurality of transverse tube members (126), each of which comprises a header member (124) via a communication port (122) through which the gas and liquid can pass. A flow pipe 122 penetrates downwardly through the communication port from each of the transverse pipe members, the flow pipe being inside the header member in the flow distribution part 34 of the distribution member 20. And opening means 123 extending at the bottom thereof, vertically extending from a side wall located inside the header member, wherein the opening means extending vertically from the wall of the flow member is the header member. It has a small enough area to apply back pressure to the backwash cleaning gas injected into it, thereby causing the formation of the header plenum 164 in the header member, whereby the backflow cleaning gas is formed in the header member. Evenly distributed from the end to the other end, even if the header member is not completely flat, the arrangement of the dispenser 158 and the header plenum 164 allows the plenum alone to more countercurrent wash water 154. And a distribution device of the culvert, characterized in that it serves to make the flow of gas (156) more uniform. 12. The method of any one of claims 1, 2, 3, 5, 7, 7, 9 and 11, wherein the plurality of first upper holes 38 for the countercurrent wash gas are Dispensing device of the culvert, characterized in that it has a total area per unit length of 90% or less, and preferably between 65% and 40% of the total area per unit length of the plurality of second lower holes 40 for the countercurrent wash liquid. . 13. The method of claim 12, wherein the plurality of first upper holes 38 for countercurrent wash gas are between 50% and 40% of the total area per unit length of the plurality of second lower holes 40 for countercurrent wash liquid. Culvert distribution device, characterized in that it has a total area per unit length. The method of claim 12, wherein the total opening area per unit length of the medium holding portion 28 of the distribution member 20 simultaneously controls the countercurrent washing liquid 54 and the countercurrent washing gas 50 in the countercurrent washing method. At least twice the total area per unit length of the plurality of holes (38,40) disposed at a plurality of vertical levels in the enclosed flow distribution section (34) provided for discharge outwardly.