EP1134323A2 - Sand trap device - Google Patents

Abstract

The sand and grit interceptor (detritor) comprises a circular tank (1) with an upward, central internal projection (3) in the base (2). The surrounding annular interception channel so formed, reduces downwardly in cross section. Preferred features: The angle of inclination is selectable but preferably about 40 degrees . An annular sand collection channel (4) is defined; its width is preferably about 30% of the tank radius. Tank depth is preferably at least 40%-50% of the tank diameter. The outer wall is upright. There is at least one scraper (10) operating near the internal base to carry sand to an extraction opening. Basal- (10) and scum- (5, 6) scrapers are turned on the same vertical shaft (8), preferably offset through 180 degrees upon it. The base scraper may be moved radially. The scraper moves the settled sand when turned in one direction; in the other, it conveys it to washing and possible aeration. The scraper lifts sand up a ramp, stirring it up. A vertical plate interceptor is included on another side, causing sand to be transported only along the channel. Aeration is provided near the cylindrical outer wall. A distributed annular aerator is provided. The fat trap (13) includes flotation lamellae. A scum separator provided, includes a scraper plate (6) moving relatively to a hopper (7). It is turned on a vertical shaft (8), the plate extending above and below the level of operation (A). The hopper inlet has a ramp, preferably two. The scum scraper plate can be tilted about an axis (9) running longitudinally through it, being at the same time spring-loaded into one position.

Description

The present invention relates to a sand trap for sewage treatment plants. Under a sand trap becomes a structure or a mechanical device for separating and removing sand and similar mineral solids from wastewater understood.

The wastewater fed to the sewage treatment plants usually contains mineral as well as organic Fabrics. Among the mineral ingredients are those that flow into the sewage system Sands, but also ash and glass. These inorganic substances can adversely affect operational safety of sewage treatment plants and sludge treatment facilities. For example, occurs increased wear in sludge centrifuges. Pipelines and Sliders block when too much sand has accumulated in the system, causing unwanted Business interruptions are caused.

It is therefore desirable to remove the sands and other mineral substances washed away in the wastewater to separate from the organic, putrefactive substances. Sand trap systems are therefore usually the actual settling tank upstream of a sewage treatment plant. In the sand trap systems are - under Exploitation of the gravitational pull on the solid particles - generally specifically heavier, mineral components separated from the lighter organic components.

In general, a distinction is made between longitudinal sand trapping and round sand trapping. While in larger systems the essentially consist of an elongated gutter Longitudinal sand trapping is used, so-called round sand trapping regularly occurs in smaller plants for use. This generally consists of a basin with a circular cross-section, the pelvis is mostly cylindrical in the upper part and in the lower part Part tapered to a point.

The inclined floor surfaces are particularly advantageous for sand traps because the sand traps them Sedimented walls and then the sand or the deposited grains on the inclined wall in Direction of the cone tip. This is essentially achieved by the fact that through a suitable arrangement of the inlet, the water flows over the sloping wall. The Waste water is usually fed tangentially to the basin. After flowing through a circumferential angle the water enters the drain at a temperature of over 180 °.

With the conical part of the pelvis tapering downwards is inevitably a very large height connected.

In order to avoid such disturbingly high structures, it is now common practice to use circular sand trap to sink into the ground, making it necessary to excavate a correspondingly deep foundation or create.

The present invention is therefore based on the object of providing a sand trap system, which, despite its compact design, has the largest possible storage volume, d. H. a large surface with a flat design and the associated long residence times of the mixed water in the sand trap and thus an effective separation of sand and other mineral solids causes, the sand trap should be inexpensive to manufacture.

This object is achieved in that a sand trap for separation and removing sand and similar mineral solids from a essentially circular cylindrical basin with a bottom that is centric - preferably essentially conical - has internal curvature.

In this way, the depth of such a round sand trap can be significantly reduced. Due to the new geometric design, the sand does not collect like conventional ones Circular sand traps in a single, deepest point, but essentially sits in one annular downward tapering gutter (sand collecting space), which is the central one Bulge surrounds.

It goes without saying that the circular sand trap does not necessarily have to be perfectly circular. Much more it is also possible, for example, to make the round sand trap oval. The circular shape is preferred, however, because the bottom of the channel is then, for example, with a central one Shaft-mounted scraper can be moved to transport sand to a discharge point. Furthermore, the cylinder basin does not necessarily have to be cylindrical. For example, the outer walls can also be slightly inclined.

In order to achieve the most effective sedimentation of the sand, the conical surface of the inner arch advantageously chosen such that they have an angle (α) of between about the horizontal 25 ° and approximately 55 °, preferably between approximately 30 ° and approximately 45 ° and particularly preferably approximately Includes 40 °. This ensures that the deposited sand quickly in the narrow floor area the tapered trough (sand collecting space) can slide off.

A particularly preferred embodiment of the sand trap system according to the invention provides that the bottom of the basin is a radially outer, substantially horizontal extending circular ring. In other words, preferably not the entire bottom of the Basin conically curved inwards, but only an inner section, so that one in the radial direction outside essentially circular flat section of the pelvic floor remains. This ensures that the annular trough has a minimum width. The sand collecting space is therefore not tapered. This has especially when pulling the Sand from the sand trap has certain advantages. It is understood that the conical inner curvature of the bottom does not necessarily have to start directly on the circular ring. It is therefore also possible to provide a hollow cylinder on the inside of the annulus, on which the conical Inner vault connects. As a result, the inner cone is offset slightly upwards, so that the sand collecting space receives an approximately rectangular cross section.

In a preferred embodiment, the width of this circular ring is between 10 and 40%, preferably between 20 and 35%, particularly preferably about 30% of the pelvic radius. Thereby, that the circular sand collecting channel has a relatively large diameter is one high sand storage capacity.

Furthermore, the depth of the basin is at least 40%, preferably at least 50% of the Basin diameter. Due to the particularly preferred geometry, the sedimentation rate of mineral ingredients significantly increased.

The inlet is preferably arranged such that the water is approximately tangential in the pool to be led. This creates a circular flow in the sand trap, sedimenting it the sand. The sand that gets into the inner area slides on the outer wall or the Cone wall down into the collecting trough. The wastewater cleaned from sand flows after one Flow distance of preferably at least about 360 ° over a threshold or through a dip tube from. The threshold is preferably arranged higher than the inlet. A particularly preferred one Embodiment provides that the (discharge) threshold is adjustable in height. This can the fill level in the round sand trap can be varied as required. The threshold is preferably one Baffle in front so that no floating substances get into the drain.

If the sand trap is used as intended, it settles on the underside of the pool the mineral sand. From time to time, therefore, the cleaning of the sand channel or the deduction of the sand necessary.

At least one clearing device is therefore preferably provided, which is located inside the basin is arranged near the bottom and is intended to form the deposited sand Transport sand discharge opening. This can while the sand trap system is working the deposited mineral sand along the circular channel to the sand discharge opening be moved. At the sand discharge opening there is, for example, a pump or a screw conveyor arranged, which discharges the sand from the sand trap.

An expedient embodiment of the present invention provides that the clearing device is attached to a substantially centrally located vertical shaft so that it can move the clearing device only has to rotate the shaft about its own axis. With large ones Systems, it is advisable to provide at least two floor clearing plates, preferably are arranged diametrically on the shaft.

For some applications it is advantageous if the clearing device is designed in such a way that if it is moved in one direction, it transports the deposited sand, and if it is moved in the other direction, whirls up the deposited sand so that it is washed becomes. The space device can e.g. B. designed to one side as a kind of plow or ramp through which the sand is lifted and swirled, while the other side is one vertical plate or other catching device through which the sand essentially only is transported in the longitudinal direction of the channel. This is also possible, for example, through a clearing device in the form of a pointed shoe or a hollow half pyramid. Will this If the shoe moves in one direction, the tip whirls the sand in the water so that it passes through the surrounding water is cleaned. If the shoe is moved in the other direction, it will Sand caught in the shoe and can therefore be reliably transported to the sand discharge opening. The quality of the sand can be significantly increased by the integrated washing device. This is particularly advantageous if the sand is not stored in a landfill should be, but should be further used.

In order to optimize the washing process, the raised or whirled up sand can expediently be used be guided via an aerator unit or a wash water unit.

A sand trap system which additionally has a fat trap device is particularly preferred. This makes it possible to remove both sand and fat from the wastewater. When arranging of fat trapping, however, care must be taken that the fat trapping does not adversely affect the sand separation affects.

A device for separating floating substances is therefore particularly preferred intended. The device for separating floating substances preferably consists of a Float removal shield and a funnel, the inlet of the funnel at the level of the working level of the basin is arranged and the floating space shield can be moved relative to the funnel is. The floating space shield can thus be moved over the surface of the water be that floating substances are "stripped" from the water surface and into the funnel be transported. The funnel exit is usually connected to a pump or conveyor system, which float in appropriate processing plants or at appropriate Deposits transported. By means of this device, there is a separation of floating substances at the same time, only a small waste water discharge is possible.

The float clearing shield is particularly preferably arranged such that it is essentially one vertically arranged shaft, which preferably runs approximately in the middle of the basin, is rotatably mounted. Part of the float shield should preferably be below and another part above the water level (working height). This ensures that on the one hand the floating substances with the help of the floating space shield effectively be transported on the water surface and secondly that the floating substances do not have the float blade can slide away.

In order to obtain a particularly effective separation of floating substances, it is advantageous if the funnel inlet of the device for separating floating substances has a ramp, via which can move the float shield to the funnel. This is particularly preferred Float clearing shield additionally by one through the floating clearing shield and vertically axis tiltable suspended to the shaft, with particular preference the floating space shield is resiliently biased into a certain position. For example, it is possible to resiliently bias the float shield into a position in which the float shield is perpendicular to the water surface. Now the floating space shield moves in a radial direction around the vertical shaft, so there may be any floating substances effectively move along the water surface. Reaches the float shield Ramp of the funnel infeed, so the funnel infeed can, if it is with the floating space shield comes into contact, tilt the float blade around its axis so that the Float clearing shield runs along the ramp and the floating substances are conveyed into the funnel.

In a special embodiment, the clearing device and the floating clearing shield driven by the same vertically arranged shaft, which also the clearing device for Drives floating materials. This makes it possible to use both the device with the same drive to remove floating materials as well as the clearing devices.

The floating material separator is advantageously arranged essentially in the center of the round sand trap. He is preferably from a calming cylinder or a baffle, which or which is slotted in the lower part or equipped with slats. This creates in Center of round sand fishing a calm area. In this can be the fats and others Floating substances reach the surface more easily. As already mentioned, the wastewater is used outdoors of the pelvis fed substantially tangentially, d. H. but that also the floating substances first swirled with the wastewater to be fed outdoors. Through the ventilation device The sand trap is created in combination with the circular flow, which Due to the arrangement of the inlet and outlet, a cylindrical flow is created. The floating substances are gripped by this current and carried away. During the cylindrical flow is directed upwards at the outer edge of the pool, the water flows downwards on the diving wall. The strength of the downward flow decreases towards the bottom. The floating substances are then there in the area of the slots or slats and drift into the calm interior where the inlet the float separator is arranged.

A further preferred embodiment provides a stripping device for stripping the inside inclined pool wall in front. This can be done for example by the arm, which the Connects the clearing device or the dozer blade to the central shaft. For example led directly along the pool floor, so with actuation of the clearing device at the same time cleaned the inner wall of the pool. Of course, this stripping device but also be constructed completely independently of the clearing device.

A special embodiment provides that a ventilation device in the sand trap system is provided. This ventilation device can be used in the circular sand trap essential cylindrical flow are generated, which separates mineral and organic matter. This flow also prevents the deposition of rotten substances in the sand. When dosing the air to be introduced, however, care must be taken care must be taken that the sand retention in the sand trap system is not impaired too much.

It has been shown that the ventilation device is preferably arranged such that it in is able to supply air substantially in the vicinity of the cylindrical outer wall. Through the rising air on the cylindrical outer wall leads to a cylindrical flow, which ensures that the water moves at a slow speed the conical inner curvature flows down. This speeds up the settling process of the mineral substances. Preferably therefore, an annular ventilation device is provided which is capable of air feed several, offset in the circumferential direction.

The ventilation device does not necessarily have to be operated with (compressed) air. Much more it is also possible with a suitable arrangement of nozzles, preferably water instead of air Industrial water, e.g. B. purified wastewater to be introduced into the basin through the aeration device. The task of the ventilation device is therefore primarily less in the ventilation of the Sewage, but rather in the production of a cylindrical flow.

Further advantages, features and possible uses of the present invention will become apparent clear from the description of a preferred embodiment and the associated figures.

Figur 1

eine Schnittzeichnung durch die Sandfanganlage,

Figur 2

eine Schnittzeichnung durch eine andere Ausführungsform der Sandfanganlage mit einem Sandklassierer,

Figur 3

eine Grundrißzeichnung einer ersten Ausführungsform der Sandfanganlage,

Figur 4

eine Grundrißzeichnung einer zweiten Ausführungsform der Sandfanganlage und

Figur 5

eine Darstellung des Bodenräumschildes.

Show it:

Figure 1

a sectional drawing through the sand trap,

Figure 2

2 shows a sectional drawing through another embodiment of the sand trap system with a sand classifier,

Figure 3

a plan drawing of a first embodiment of the sand trap,

Figure 4

a plan drawing of a second embodiment of the sand trap and

Figure 5

a representation of the dozer blade.

In Figures 1 and 3 is a sectional drawing and a plan view of a first embodiment shown the sand trap system according to the invention. It can be clearly seen that the pelvis 1 is essentially cylindrical. The floor 2 consists of a horizontal Annular ring 4 and a substantially conically curved section 3 a vertically extending rotatable shaft 8, a floating space shield 6 is arranged, the forms a float cleaner together with the funnel 7. The float blade 6 is rotatably supported about the horizontal axis 9 and biased such that it has no effects external forces is perpendicular to the water surface. The opening of the funnel 7 is located at the working height A of the sand trap. The working height is determined by the height of the spout 18 determined.

The filled water is made up of organic and mineral components as well as floating substances together. If the shaft 8 is rotated, the floating space shield will graze 6 over the water surface and transports the floating materials in the direction of the funnel 7. A ramp is attached to the funnel inlet. Comes the float shield 6 with the Ramp in contact, the buoyancy shield 6 tilts due to the through the ramp force applied to the float shield around the axis 9. Possibly existing Floating substances are conveyed through the floating substance clearing plate over the ramp of the funnel up to Funnel opening transported so that the floating materials are transported into the funnel 7 and can be discharged via a transport pump 13. The float scraper shield grazes along the funnel ramp.

A grease trap 13, which consists of individual flotation lamellae, can also be clearly seen consists. The flotation lamellae are arranged parallel to one another and extend axially Direction down into the pool. In the embodiment shown, the slats form one Lamellar ring with a radius between approximately between 40 and 75% of the pelvic radius. The slats are preferably, as can be seen in Figure 1, surrounded by a partition 19, which is in the axial Dip into the direction of the pool. The partition 19 does not reach the floor; the partition 19 therefore has approximately the shape of a hollow cylinder and extends in the axial direction in a length of about 40 to 80% of the working height. Through the partition 19 is a grease trap separated, in which the floating substances are dislodged due to the flotation effect of the blown-in air become. For this reason, the floating space shield 6 extends in this embodiment also not to the edge of the pool, but only to the edge of the partition.

Also connected to the shaft 8 is a clearing device 10, which is preferably the floating clearing shield 6 diametrically opposite. The clearing device 10 runs on the bottom of the Basin essentially in the circular horizontal section of the bottom. In Figure 3 is the special shape of the clearing device can be seen particularly well. It essentially has that Shape of a hollow half-cone or a half-funnel or a hollow half-pyramid.

If the clearing device in Figure 3 is moved counterclockwise, it may be on the Sand deposited on the bottom was taken up through the funnel opening and along the bottom of the pool transported until the sand discharge opening is reached in the vicinity of the sand feed pump 14. The sand collected in the funnel then falls into the sand discharge opening and can be used with suitable ones Discharge devices are withdrawn from the basin.

If, on the other hand, the clearing device is moved clockwise, the tapering one acts (Half) funnel or cone shape as a plow or ramp and the sand is through the cone surfaces the clearing device whirled up so that it is washed or of any adhering organic Ingredients are exempted. As can be seen in Figure 5, the dozer blade has one Aerator unit 20, which can add air to the raised sand, so that the cleaning of the sand is done even more thoroughly.

If, for example, the sand is heavily contaminated with organic ingredients, it can Sand is first washed by moving the clearing device clockwise. To the washing process, the direction of rotation of the clearing device can be changed so that now the washed sand is transported to the sand discharge opening or the sand feed pump 14 and is withdrawn from the pool. The hopper 7 has ramps on both sides, so that Float in both directions of rotation of the shaft 8 is transported via the ramps into the hopper 7 become.

In addition, there is a ventilation device on the inside of the outer wall of the cylindrical basin 11 provided. This has a plurality of openings 12 in the circumferential direction. If necessary, it is possible to introduce 12 air into the basin through the ventilation openings, so that due to the Ascending air creates a substantially cylindrical flow within the basin. This flow additionally prevents digestible ingredients from accumulating on the pool walls or deposit in the sand collecting room.

The flow conditions in the sand trap are marked by arrows. The waste water is through the line 17 introduced into the basin. The line 17 is arranged such that the inflowing Water in the sand trap causes a counter-clockwise radial flow. As can be seen in Figure 3, the wastewater in the basin passes through a circumferential angle of at least almost 360 °. Just before the waste water goes through a full revolution in the pool has, at least some of the water can exit the basin via the overflow 18. The Flow speed of the water in the sand trap system must not be too high, so that in the the mineral ingredients on the inwardly curved conical bottom wall can settle and transported along the inclined surface to the outer gutter become. If the pelvis is simultaneously ventilated with the aid of the ventilation device 11, this results by the superposition of the radial flow with the cylindrical flow, which is caused by the Ventilation is caused by a spiral flow. It is known that such turbulent Currents favor the separation of organic and mineral ingredients.

Figures 2 and 4 show a second embodiment of the present invention. It makes a difference differs from the first embodiment only in that instead of the sand feed pump a sand classifier 16 is provided. The sand classifier at least partially finds one Separation of the mineral and organic components of those separated in the sand trap Solids and a drainage of the sand trap instead. The sand classifier separates the solids in two different partitions, which are mainly characterized by particle size and particle density differentiate. One part has a higher proportion of organic components. This part of solids is returned to the clarification process. By using a sand classifier the quality of the sand is significantly improved, the desanding performance of the However, sand trap is reduced. It must therefore be decided individually depending on the area of application whether a sand classifier is beneficial or not.

The sand trap system according to the invention has a relatively large surface area with a low overall height on. It is therefore advantageous to use a device for the separation of floating matter, which is due to the large surface area can realize a large floating material separation area. By the essentially vertical outer walls of the pool become a correspondingly large pool volume reached, which entails relatively long residence times of the waste water in the basin.

The pool is preferably made of stainless steel, but it can also be made of other materials, such as B. made of reinforced concrete. The pool is either placed on the floor or built into a pit.

Claims (21)

Sand trap for separating and removing sand and similar mineral solids consisting of an essentially circular pool (1) with a pool floor (2) and a working fill level (A), an inlet and an outlet, the pool floor has a central inner curvature (3), whereby a ring-shaped circumferential is formed at least partially in cross-section tapering down the gutter. Sand trap system according to Claim 1, characterized in that the lateral surface of the inner curvature with the horizontal forms an average angle (α) between approximately 25 ° and approximately 55 °, preferably between approximately 30 ° and approximately 45 ° and particularly preferably approximately 40 °. Sand trap system according to claim 1 or 2, characterized in that the bottom of the basin has an essentially horizontal circular sand collecting trough (4) lying on the outside in the radial direction. Sand trap system according to claim 3, characterized in that the width of the sand collecting channel (4) is between 10 and 40%, preferably between 20 and 35%, particularly preferably about 30% of the pool radius. Sand trap system according to one of claims 1 to 4, characterized in that the depth of the basin is at least 40%, preferably at least 50% of the basin diameter. Sand trap system according to one of claims 1 to 5, characterized in that the outer wall of the Bekken is arranged essentially vertically. Sand trap system according to one of claims 1 to 6, characterized in that at least one clearing device (10) is provided, which is arranged within the basin near the bottom, and is intended to transport deposited sand to a sand discharge opening. Sand trap system according to Claim 7, characterized in that the clearing device (10) and the float clearing shield (6) are driven by the same vertically arranged shaft (8) and are preferably arranged on diametrically opposite sides (offset by 180 °) on the shaft (8) are. Sand trap system according to claim 7 or 8, characterized in that the clearing device (10) can be moved in the radial direction along the bottom of the basin. Sand trap system according to Claim 9, characterized in that the clearing device (10) is designed in such a way that, when it is moved in one direction, it transports deposited sand, and when it is moved in the other direction, it moves the deposited sand, that it is washed and ventilated if necessary. Sand trap system according to Claim 10, characterized in that the clearing device (10) is designed on one side as a kind of plow or ramp, through which the sand can be raised and swirled, while the other side is designed as a vertical plate or other catching device, through which the sand can be transported essentially only in the longitudinal direction of the channel. Sand trap system according to one of claims 1 to 11, characterized in that a ventilation device (11) is provided. Sand trap system according to claim 12, characterized in that the ventilation device (11) is provided for supplying air substantially in the vicinity of the cylindrical outer wall. Sand trap system according to claim 12 or 13, characterized in that an annular ventilation device is provided which is capable of supplying air at several points (12) offset in the circumferential direction. Sand trap system according to one of claims 1 to 14, characterized in that a grease trap (13) is provided. Sand trap system according to claim 15, characterized in that the fat trapping device has flotation lamellae. Sand trap system according to one of claims 1 to 16, characterized in that a device (5) is provided for separating floating substances. Sand trap system according to claim 17, characterized in that the device (5) for separating floating substances has a floating space shield (6) and a funnel (7), the floating space shield (6) being movable relative to the funnel (7). Sand trap system according to claim 18, characterized in that the float clearing plate (6) is arranged rotatably about a vertically arranged shaft (8), at least part of the floating clearing plate being arranged below and at least one other part above the working fill level (A). Sand trap system according to claim 18 or 19, characterized in that the funnel inlet has at least one ramp, preferably two ramps. Sand trap system according to Claim 20, characterized in that the floating reagent shield (6) is suspended so that it can be tilted about an axis (9) extending in the longitudinal direction through the floating reagent shield, the floating reagent shield (6) preferably being resiliently biased into one position.

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