FI90113B - Method for dredging silt from harbours, watercourses or the like and a dredging vessel - Google Patents

Abstract

A process and device are disclosed for dredging silt deposits in ports, waterways, etc. by means of a slope conveyor. The silt upper layer (25) is undercut, gathered by means of a receptacle (5, 19, 20) and removed by means of a mechanical slope conveyor (tubular conveyor (2)).

Description

90113

Method for dredging sludge from ports, waterways or similar and dredging vessel Förfarande för att muddra upp slam frän hamnar, vattenvägar eller motsvarande och ett mudderfartyg 5

The invention relates to a method for dredging sludge from ports, waterways or the like by means of a height-adjustable and adjustable bearing-inclined inclined conveyor and an associated intake head 10.

The invention also relates to a dredging vessel for carrying out the method, which is provided with an inclined conveyor, the water-side end of which has an intake head provided with adjustable cutting blades.

15

Bucket chain dredgers, tow suction dredgers and other dredgers are known to be used for dredging ports, waterways or the like, in which the sludge is lifted mechanically or using pressurized water and transported upwards to dredger barges or landing surfaces by means of inclined conveyors. All of these known transportable devices use excavator devices, as well as bucket frames, bucket wheels, cutting wheels or the like, as well as suction heads, by means of which the sludge is removed from the surface of the sludge, possibly using pressurized water. This creates water vortices in the area of the excavator heads or suction heads, which vortex the sludge more or less and distribute the deposited materials in the water.

DE-B 2 837 322 describes a device by means of which sludge accumulated at the bottom of fairways, canals or other waterways is sucked out by a suction pipe 30 arranged at the end of a suction line, which in turn is supported by the hull of the vessel. In this device, the suction mouth is connected in the working direction: as seen from the return device. This may consist of a carriage and a return mechanism fixed to it. It can then support two roll-shaped brushes which are operably mounted and parallel to each other in the suction box. This suction box, in turn, may have an opening for the suction nozzle on the front side extending transversely to the brushes. In this case, the sled-shaped suction box can be provided with floats between which the suction mouth is located.

DE-A 2 059 436 describes a sludge dredge, the towing member 5 of which is formed by a substantially rectangular box which has a side view in the form of a carriage and which is pulled over the sludge to be transported. The sludge is taken out of the box when it is emptied and the traction movement is started. The receiver may be assisted by a lift arranged at the mouth of the box. This machine can be used to lift flat and slightly compressed pond bottoms.

DE-A 3 150 993 describes a method for removing deposits from waterways, and in particular those containing harmful substances and organic constituents. In this case, the deposits are lifted up on site and then mechanically screened. The sieved layer is mechanically dewatered, after which at least a fine-grained mineral additive is mixed into the anhydrous layer. This mixture is dried to granules, after which the granulated material is burned. The blown and burned granulated material 20 is further processed. This granulated product can be used as a light additive for the production of building materials. The light additive may consist of clay, fly ash or the like. Additives can also be added to the granulated product. In mechanical enrichment, oversized granules can be separated and sorted. The filter water remaining from the mechanical dewatering can be purified and returned to the waterway.

DE-A 1 918 332 describes a method and device for conveying solids in a liquid. For this purpose, a suction dredger is provided which has a suction mouth connected to the suction pipe and in which the suction pipe is connected to the suction pump. An additional device is connected to its transport pipe, which is used to accelerate the deposition of solids. Polyelectrolytes can be used as such devices. The outlet of the transport pipe is passed over a relatively short conveyor belt located above the barge. The rearwardly advancing portion of the conveyor belt has a scraper to ensure that the deposit is scraped from the conveyor belt. In the barge, the deposit is separated.

Il 3 90113

Too much water flows out. The use of additional deposition accelerators is detrimental in this context.

If no additional sedimentation accelerators are used, all known dredging methods have the disadvantage that the natural dewatering of the sludge requires a very long time. Therefore, large bottom surfaces that could be used for other purposes are also stressed during sludge removal. If the sludge or the transport water required for its discharge is treated with harmful substances, 10 these may also enter the groundwater during discharge.

GB-A 2 128 663 discloses a suction head dipper having a suction pipe attached to the hull of a vessel and provided at its water end with an intake head. A cutting blade mounted on the body 15 is arranged across the entire width of the intake head, whereby the body can be moved by means of a vibrating device at the frequency of oscillations. The disadvantage of this suction head dredger is that it can only cut the surface areas of the base so that the amount of water sucked in relation to the raised base is very large. Possible follow-up measures such as water-20 removal, drying, etc. also become relatively expensive.

The object of the invention is that when the deposits are lifted from the bottom of the channel, as few vortices as possible are generated, and above all that the additional water is transported as little as possible in order to avoid thinning of the conveyed sludge. Also, when separating sludge from sand, as little water as possible must be used so that the costs of the methods do not increase and the environment is not harmed. Sludge enrichment and separation takes place on board. Further processing must be as simple as possible.

30

The object is achieved by the method according to the invention by introducing the suction head from below the top layer by cutting into the slurry and moving it so that the top layer above the suction head forms a separating layer between the free water and the newly created surface, which is also maintained when the suction head is moved forward and covers the newly formed surface behind the suction head. wherein the slurry obtained below the separating layer is lifted by means of an intake head and transported away by a mechanical inclined conveyor.

In order to achieve the objects, the dredger according to the invention is further characterized in that the distance of the cutting blades can be varied to control different amounts of sludge, the cutting blades being equipped with hydraulically controlled setting devices and the separating layer above the

10

According to the invention, the deposit accumulated above the bottom of the fairway is lifted in such a way that only a part of the deposit in the lower part is lifted in the direction of the slurry by means of a suction head movable. In this case, the remaining top layer of sludge, which is located above the upper cutting edge of the intake head, is discharged from above and remains as a separating layer between the newly formed surface and the free water. In this case, the presence of vortices in the water in the region of the sludge-raising head can be avoided, and in addition to this, the advantage is achieved that the amounts of water transported remain very small. The separation -20 layer above the intake head flows away through the intake head via the control head, corresponding to the progress of the dredger, and covers the _ 1 bus bottoms released behind the intake head.

According to the claimed embodiment, the transport water subsequently required at the end of the intake head 25 can be led downwards.

The sloping transport of the sludge takes place by mechanical conveyors, for example spiral or scraper chain conveyors.

The details of the invention are illustrated by the embodiments shown in the drawing, and the following is shown in the drawing:

Figure 1 shows a method according to the invention; Figure 2 shows a side view of a dredging platform for carrying out the method according to the invention;

Figure 3 is a plan view of Figure 2;

II

5 90H3

Figure 4 is a side view of the larger view of the intake head of Figures 1 and 2.

The dredger 1 is provided with a transport pipe 2, which is suspended and lowered by a rope hoist 3 on a rope winch 4.

A suction head 5 is pivotally attached to the front end of the transport tube 2 about a horizontal axis 6. The pivoting is arranged by means of a rod 7 which engages at 8 a tie rail 9 fixed to the structural part of the intake head 510. The bar 7 leads to a fastening device 10 arranged at the upper end of the transport pipe 2. The bar 7 acts as a guide for rectilinear movement, which ensures that the lower intake head cutting always takes place horizontally, regardless of the dredging depth.

This lower side 11 of the intake head 5 is fixedly connected to it. The upper side 12 is pivotally articulated about the shaft 13. The sampling head 5 the upper side 12 of the height position is adjusted by means of a hydraulic transmission device 14 according to the desired section thickness.

Under the intake head 5 11 or on the movable top 12, cutting blades 17, 18 are provided by means of oscillating elements and vibrating drives 15,16. The side walls of the intake head 5 can be similarly provided with vibrating cutting blades. It is also possible to form 1: side walls to be displaceable in the same way as the upper side wall of the intake head.

The two intake heads 19,20 are located side by side in the exemplary embodiment. They ... cover several meters wide.

The dredging platform 1 is advanced by two transfer columns 21, which are placed on the bottom of the fairway, if necessary, and on which the dredging platform 1 is pulled forward. 1 'A sonar 23 is attached to the front of the dredger 1 by means of a projection 22.

The other structure of the dredger and its mode of operation are illustrated by the following description: 6 9 Π1 1 3

The layer thickness of the layer to be transported (slurry 24) is measured in front of the intake head 5 by sonar 23, and at the same time the state of the bus bottom is determined. Depending on the layer thickness, the inlet height of the intake head 5 is adjusted and the advancing speed of the dredger 1 is set so that the desired and set quotient 24 of the sludge , 20 and past the transport pipe 2 and re-deposits behind the intake ends on the bus bottom. When slurry 24 10 is thus transported, only the deposit is lifted. Thinning of the deposit due to the surrounding water and contamination of the water due to eddies are avoided during transport.

The lifted deposit is conveyed in the conveying tube 2 by a helical conveyor, a scraper conveyor or other suitable mechanical conveyor, not shown in more detail, obliquely upwards and led to a coarse separator. The coarse material flows up along the horn 28 to the barge 29.

20 A drum screen or other can be used to separate coarse material. . suitable device.

During the upward transport of the conveyed sludge, the thickness of the sludge and its composition are measured and process line 25 is passed through line 30 to such an extent that the sludge mixture flowing through line 31 becomes pumpable and separable in hydrocyclones 32.

The sand flowing from the hydrocyclones 32 is passed to an upstream sorter 33 and processed there. From the sorter 33, the sand flows into the dewatering-30 screen 34, after which the obtained sand is led through a trough 35 to barges (not shown).

The described sand separation is currently followed by sludge dewatering.

From the hydrocyclones 32, the sludge is optionally passed through a water separator 38 and a transfer basin 39 or an intermediate water tank to a centrifuge 40. It transfers the dried sludge to an exhaust gas heated dryer 41 and draws I) 7 91313 out of clay at 42. The dried clay can then be transported to storage by self-draining or decontamination.

Additional process water that accumulates in the pump sump 43 from all possible outlets can be led from there via the return line 44 back to the outlet openings 45 arranged behind and below the inlet end 5 or 19.20.

The method according to the invention has the advantage that the deposit is transported only in the pore water contained therein and that only a relatively small amount of pore-water is required to treat the slurry, which can be led back to the path without special vortices.

15

A degassing system for on-board diesel engines can be used to heat the dryer 41.

8 9 fl 1 1 3

Description of reference numbers: 1 Dredger 2 Transport pipe 5 3 Rope hoist 4 Rope winch 5 Intake head 6 Horizontal shaft 7 Rod 10 8 (Grip point) 9 Coupling rail 10 Fastening device 11 Bottom 12 Top side 15 13 Shaft 14 Hydraulic cylinder 15 Swing element 20 Swing element 16 Swing element 16 Swing element Intake head 21 Transfer column 22 Cantilever 25 23 Sonar 24 Slurry 25 Top layer 26 Separation layer 27 Coarse material separation 30 28 Sliding gutter 29 Barge 30 Line 31 Line 32 Hydrocyclone 35 33 Ascent current sorter 34 Drain screen 35 Gutter trough 39 9 Π1 1 3 36 Hydrocyclone 5 40 Centrifuge 41 Dryer 42 (Clay) 43 Pump socket 44 Line 10 45 Outlet opening

Claims (12)

A method for dredging sludge from ports, waterways or the like on a dredger (1) by means of a height-adjustable and adjustable 5 inclined inclined conveyor (2) and an associated intake head (5.19.20), characterized in that the intake head (5,19,20) is taken from the top layer (25) by cutting into the slurry (24) and moving it so that the top layer (25) above the intake head (5,19,20) forms a separating layer (26) between the free water and the newly created surface, which is also maintained at the intake head ( 5,19,20) when moving forward and which behind the intake head covers the freshly formed surface, whereby the slurry (24) obtained below the separating layer (26) is lifted by the intake head (5,19,20) and transported away by a mechanical inclined conveyor (2). 15 Method according to Claim 1, characterized in that the height of the sludge and the bottom layer of the passageway are determined by means of a sonar (23) arranged in front of the intake head (5.19.20) and then the depth of descent of the intake head (5,19,20) and its adjustable cutting height. adjusted to the measured sludge height. Method according to Claims 1 and 2, characterized in that the forward speed of the dredger (1) is adjusted depending on the amount of material conveyed in the inclined conveyor (conveying tube 2) so as to avoid vortices in the intake head (5, 19, 20). Method according to Claims 1 to 3, characterized in that the conveyed sludge is passed through a coarse material separator (27). Method according to Claims 1 to 4, characterized in that the coarse material separator (27) is a drum screen. Method according to Claims 1 to 5, characterized in that the thickness of the slurry and the content of the organic layer are measured and, after or during the separation of the coarse material, so much process water is added that the slurry becomes pumpable and separable in a sludge separator known per se (hydrocyclone 32). Method according to Claims 1 to 6, characterized in that the process water is led in the direction of travel of the intake head (5, 19, 20) as seen from its end back under the sludge layer (26) remaining on the waterway bottom. Method according to Claims 1 to 7, characterized in that the clay is dried and that the heat of the exhaust gases from the ship's diesel engines is used for drying. Dredging vessel provided with an inclined conveyor (2) having at its water end an intake head (5,19,20) with adjustable cutting blades (17, 18) for carrying out the method according to claims 1-8, characterized in that the cutting blades (17, 18) the distance can be varied to adjust different amounts of sludge (24), the cutting blades (17,18) being provided with hydraulically controlled setting devices (14), and that the separating layer above the intake head (5,19,20) or the cutting blades (18) 26) can be guided according to the forward speed of the dredger (1) over the control damper connected to the intake head (5,19,20). Dredger according to Claim 9, characterized in that the cutting blades (17, 18) are provided with adjustable vibrating drives (15, 16). 10 90113 Dredging vessel according to Claims 9 and 10, characterized in that the process water return line (44), viewed in the direction of travel of the intake head 30 (5,19,20), opens at its rear end and below it. 12 ^ 0113