DE1955944B2 - Method and device for loading a suction dredger - Google Patents

Description

The invention relates to a method and a device for loading a suction dredger with Dredged material, e.g. B. sand, in which a water-dredged material suspension is pumped into the hold of the ship is, from which dredged material settles, with

as the loading space in a first loading process step essentially filled with the water-dredged material suspension and in at least one subsequent second loading process step further water-dredged material suspension pumped into the hold and water or diluted suspension from the upper one Part of the hold is removed, preferably until the suction dredger is substantially up is loaded with deposited dredged material to its maximum load-bearing capacity.

It is known in this context to carry out the loading in at least two steps. In a first process step, the hold is filled with the water-dredged material suspension, from which the dredged material, z. B. sand,

4u begins to set. This is when the hold is first completely with the water-sand suspension is filled, a total of only a relatively small amount of sand in the hold, which is begins to settle out of the suspension. To determine the proportion of settled sand, i.e. H. the actual payload to increase further, is then further in one or more subsequent process steps fresh suspension is pumped into the hold, while at the same time water or diluted suspension overflows or is otherwise discharged at the upper edge of the hold. This procedure will be like this continued for a long time until the amount of settled sand in the hold no longer increases appreciably. The settling speed of sand depends on the size of the sand grains and the flow speed depending on the suspension in the hold. With a certain cross-section of the cargo space the free flow cross-section increases as the amount of sand deposited increases the settled sand smaller; Assuming constant Förderlei stung of the pump, therefore decreases the flow rate the suspension located above the settled sand, which increases the settling speed is decreased. This can go so far

ή ₅ hen that practically no more sand can settle and thus the overflowing suspension has practically the same sand concentration as the freshly supplied suspension, in effect thus the entire with

I 955 944

the fribch-fed suspension of the sand that has been brought in goes overboard again with the overflow. For a given grain size, a given delivery rate of the pump and a given cross-section of the hold, the maximum achievable ratio of the volume of the deposited. Sand to the volume of the hold is also known as the fill factor. In the known suction dredgers and loading methods for these, the loading space is designed in such a way that, when largely filled with settled sand in the final stage of the loading process, the loading weight is essentially the maximum permissible load capacity of the; Saugbaggerscbiffes corresponds. Since the specific gravity of wet sand is around 2 (t / ra *), the loading space of sand suction dredgers, also known as a> hopper, is usually designed so that the amount of its volume (in m ³ ) is approximately half the numerical value of the carrying capacity of the Ship (in t) c iitspriclit.

Since such a hold as a result of the above, The effect reproduced by the fill factor is not completely filled with settled sand can graze, it has also already been proposed to fold down the cargo space at its upper edge A. to provide exhaust flaps in such a way that under otherwise the same conditions a little more sand can be brought into the room: this can even be attempted in a third charging process step again to bring additional sand into the room by turning off the suspension supply the sand can settle and then the water above it by means of the mentioned Drain flaps can drain. This third step can also be repeated several times if necessary.

This known overflow method for filling a hold, the volume of which is essentially is dimensioned so that the cargo weight approximates to. full filling of the hold with settled sand, essentially the maximum permissible load-bearing capacity of the ship, are off even when using the aforementioned hinged drainage flaps very time-consuming and therefore less economical for the reasons mentioned above, quite apart from the fact that that the achievable fill factor remains not inconsiderably below 100% even with repeated repetition of the third loading steps mentioned.

These disadvantages also apply to the dredger known from German patent specification 487 235 and charging method, which differs from the above-mentioned overflow method only in that that the removal of the water or the dilute suspension ver in the course of the second and the possible subsequent loading steps not by simply overflowing at the upper edge of the loading space takes place, but by suction through suction ports in the upper part of the side walls of the hold or in the ceiling of the hold; the suction ports of these suction nozzles are provided with filters to separate the dredged material from the water.

In Blaum, from Marnitz »The floating excavators«, Berlin 1963, Vol. I, pp. 280, 282, 283, it is recommended to adjust the absorption capacity of a Dredging vessels en loads of different densities, which can vary between 1.2 and 2.2, the volume Make the holds large enough to accommodate the lightest cargo and when loaded to fill only part of the cargo hold of the cargo ship with heavy material, one has to do the opposite Fafi, at Bagger & Chiffen, only for heavy Charging were designed to hold the volume of the cargo space

makeshift attachments made of wood or stan »increase the load capacity for light loads to be able to make better use of the ship. In both cases, however, the loading volume or the Overflow height not increased during the loading process

changes, and the charging process is based on the overflow principle carried out.

The invention is based on the object of providing a method for loading suction dredgers ut.d a necessary to use this loading procedure

to create speaking trained suction dredger, which allows the dredger to be loaded with dredged material to one of the maximum permissible load capacities of the Ship corresponding value in a shorter time, or, for a given period of time, to a higher one

ao percentage of the maximum permissible load capacity of the Allow dredger than by the method mentioned at the beginning.

According to the invention, this object is achieved in that, in the first step of the loading process, the loading space up to the maximum permissible load capacity of the suction dredger with that conveyed by the suction dredger Suspension is filled, and that in the second step of the charging process with the pumping in of further Suspension accompanying discharge of water

or diluted suspension in the upper part of the hold depending on the increase in the middle Charge density is controlled so that the weight of the deposited dredged material and water or diluted Suspension of the existing charge

to a constant value corresponding to the maximum permissible load capacity of the suction dredger is held.

The invention is based on the basic idea that the loading process is significantly shortened can be achieved when the largest possible volume of suspension is brought into the hold and substantially the maximum carrying capacity of the dredger for as long a period of time as possible is exploited. This means that with a specific weight of the suspension of 1.1, it is almost double as much suspension is loaded in the first charging step as has been customary up to now, a prerequisite this is because the cargo space used for loading has a larger volume than usual is designed for a given maximum load-bearing capacity of the ship. By according to the invention further "provided controlled water drainage in the course of the second process stage, such that the total weight of the load is essentially at the limit of the maximum load capacity of the Schifies is held, it is ensured that on the one hand loaded with optimal efficiency and on the other hand exceeding the permissible carrying capacity of the ship is avoided.

Optimal efficiency is achieved here for the following reasons:

Due to the practically complete utilization of the ship's carrying capacity, there is a maximum of cargo space, in which there is water and not yet settled dredged material is available. It is therefore included on the load-bearing capacity - maximum free flow cross-section over the settled sand and thus achieving the highest possible settling speed.

The efficiency of the charging process is considerably increased by the fact that this occurs during the charging time the suction dredger loaded to its maximum load capacity lies as deep as possible in the water, so that the suction pump connected to the ship is as deep as possible in the water and so on The lowest possible altitude is arranged above the dredged material to be sucked up from the ground. The for Lifting the excavated material required suction force is reduced, so that the thereby released Suction power reserve for sucking up a heavier suspension, d. H. a suspension with a higher concentration of dredged material, can be applied.

Of course, this further reduces the loading time, since the settling speed increases with the concentration of dredged material grows strongly in the absorbed suspension.

The invention also relates to a suction dredger designed for loading according to the invention Method with a loading space, a pump for supplying the water-dredged material suspension conveyed by the suction dredger in the hold, a drainage device for draining water or dilute water-dredged material suspension from the upper part of the hold and with a draft measuring device, whereby the hold volume is larger is dimensioned as for the inclusion of the loading of the suction dredger to its largest permissible Load capacity corresponding to the largest volume of dredged material is required. According to the invention is thereby provided that the inlet openings of the drainage device are arranged adjustable in height, the Draft values measured by the draft measuring device for controlling the height-adjustable Inlet openings of the drainage device are used. It is already from Hansa 1965, No. 22, pages 2110 to 2114 known to determine the amount of charge of a suction dredger by measuring the depth with pressure sensors.

According to a particularly advantageous embodiment of the invention it is provided that as a drainage device one or more suction cups are provided in the cargo space.

The use of suction cups to drain water on top of a closed one Chamber formed hold of a suction dredger is from the USA. Patent 934 593 at known.

According to further expedient refinements, one controlled by the depth measuring device can be used Safety device may be provided which responds as soon as the weight of the load is in the hold exceeds a predetermined value. The safety device can serve in the case of the Response to cause a lowering of the inlet openings of the drainage device, if exceeded a predetermined safety limit, it can actuate an alarm device and / or switching off the pump for supplying the suspension into the hold and, if necessary, the actuation of unloading devices arrange for the cargo to be removed from the hold.

In the following, embodiments of Invention explained with reference to the drawing. It shows

Fig. La and 1 b a graphical representation for Illustration of the known method for. Loading a suction dredger,

F i g. 2 a and 2 b graphical representations for illustration of the method according to the invention, FIG. 3 in a schematic longitudinal sectional view Suction dredger,

F i g. 4 is a plan view of the suction dredger according to FIG. 3, and

5 shows a block diagram of the control and safety device of the suction dredger according to FIGS. 3 and 4.

In Fig. La and 2a represent the dashed line V ₁

ίο the total volume of suspension and settled sand and the solid line V _s the volume of the settled sand, in Figs. Ib and 2 b the dashed line W ₁ the total weight of suspension and settled sand and the solid line W _s the Represents the weight of the settled sand, in each case as a function of time. To designate the volumes or weights at the points in time B, C, D, E, F, G, H , the corresponding letter is added to the index. So for example

ao, V _{lH is} the total volume at time H and W _{sC is} the weight of the settled sand at time C.

When comparing the method according to the invention with the known method in FIGS. 1 and 2

»5 are - '' he pump delivery rate, the pumped suspension and the maximum permissible carrying capacity of the suction dredger is approximately the same.

To transport a volume V _sH (m ¹ ) of wet sand (Fig. 1 a), the conventional method

3 «ren used a suction dredger with a maximum volume V _R , which can be reduced to a volume _{V p} by means of foldable drainage flaps.

When carrying out the known method, suspension is pumped into a hold of a suction dredger ship during a first loading process step 3 (Fig. 1 a, 1 b), which begins at time O and extends to time A , at which the hold all the way to the top is filled. The hold has drain flaps that are closed during the first loading step 3. In this first loading method step 3, the volume V _s and also the weight W _{s of} the sand that has settled in the silt increases greatly. During the subsequent second loading process step 4 in line AD , suspension is continuously pumped into the hold, while the same amount of liquid with a continuously increasing content of sand flows over it. The increase in the settled sand has fallen to such a small value at time D that the continuation of the second loading process, step 4, is not expedient. Therefore, at time point D, the pumping in of the suspension is stopped and, in a third loading process step 7, the sand in the suspension is given the opportunity to settle down.

At the time F, the drain flaps are geöff net, so that the upper water then flows off. The loading space volume is then equal to V _p . Thereafter, in a fourth charging process step 8, the drain flaps are first closed again and the charging chamber is again pumped completely full of suspension in the period FG. In the period Gf / the sand settles in the suspension while no suspension is being pumped in. At time H this is desired

«5 sand volume V _jff reached.

3 and 4, a suction dredger is zui Carrying out the method according to the invention is provided.

This suction dredger 11 has a drag suction dredger, with a loading space 12 and a pump 10, which is connected on the one hand to a drag suction pipe 9 and on the other hand to a discharge pipe 15: the suction dredger also has swiveling deep into the loading space 12 as drainage devices 16 _p , 16 , serving suction cups. Each suction lifter has a stationary lifting tube 41, which is connected on the one hand to a tube 20 and on the other hand via a flexible line 42 to a height-adjustable suction nozzle with an inlet opening 43 which is articulated to the lifting tube 41 and which is actuated by means of a hydraulic adjusting device 17 or 17 will. On the floor of the loading space 12, funnel-shaped outlet openings 18 provided with unloading flaps are provided as unloading device 19.

The loading of this suction dredger takes place according to the method according to the invention as follows:

In a first loading process step 13 (Fig. 2a, 2b) is into the loading space 12 via the pouring pipe 15 is pumped by the pump IO from the suction pipe 9 sucked up suspension until the suction dredger 11 is loaded to its maximum permissible load capacity.

The loading space 12 is now filled with a sand-water mixture from which a volume of sand V _{SB has} settled at time Π. The drainage devices 16 _p , 10 _{1 designed} as suction lifters are now in a raised position, not shown in FIG. 3, in which their inlet openings 43 are above the water level and the suction lifters are therefore ineffective. In the second Laoever procedure step 14 that follows, additional suspension is pumped into the hold 12, while the suction lifters are inserted into the hold 12, to a depth such that so much liquid flows through the suction lifters and the pipes 20 connected to them into the outboard water flows away that the suction dredger just remains loaded only up to its maximum permissible load capacity. The suction lifters are gradually lowered from the mentioned raised position into the position shown in FIG.

FIG. 2a illustrates 2b that the total required charging time OC of the charging process steps 13 and 14 is less than the total required in the known method of Fig. La, Ib charging time OH, although the sand volume V _sc in- time C in F i G. 2 in the method according to the invention is equal to the final sand volume V _SH at the end point H in FIG. 1 in the known method. The short loading time OC is a consequence of the fact that in the method according to the invention the suction dredger is always loaded to its maximum permissible carrying capacity during the second loading process step 14. The total weight W _{1 of} the load is then always at a maximum (see FIG. 2b), while the total weight W ₁ in FIG. 1 b gradually increases in the second charging process step 4, but always remains below the maximum value W _1.

Weight W _{1 of} the cargo is determined from the draft of the suction dredger. For this purpose, the depth by means of a Tiefgangsmeßvorrichtung 2iL, 22 _r, 22 is measured. As the draft measuring device 22 ^ ,, 22 _C , 22, pressure measuring sensors are provided, which are arranged in each case in the suction dredger It, and which each have a pressure-sensitive membrane 23 as a sensitive element, which delimits a chamber 24 which is connected to the outboard water 21 stands. Each of these pressure sensors perceives a pressure corresponding to its immersion depth, which is a measure of the draft of the suction dredger and thus of the weight of its cargo. There are a total of nine pressure sensors, those on port. Are arranged starboard and in the ship's central longitudinal axis as well as in front, behind and in the middle of the suction dredger.
During the second loading step 14 is

ίο automatically the associated one for each load condition The cargo space is adjusted so that the overflow loss is minimal.

In Fig. 5, an automatic control device is shown schematically, but not the subject this property right belongs, but only serves to explain it.

Here, 25 _ρ , 25 _C and 25 _{t are the recipients of the information from the pressure sensors of the draft measuring device 22 p} , 22 _C and 25, which are arranged independently of one another on the port side along the central longitudinal axis or on the control flange side (FIGS. 3 and 4). From this information, the associated η depths are calculated in arithmetic units 26 _Λ , 26 ₍ and 26. The results of these arithmetic units are fed to a depth and inclination arithmetic unit 27, which feeds data to a depth indicator 28, an inclination indicator 29 and a safety device 30: the arithmetic unit 26, also provides data on the drafts on the starboard side to a

Comparison and computing device 31, which in turn supplies signals to a signal converter 32 for the control 1-K, ^ siphon of the drainage device 16; the signal converter 32 controls the application of the control slide 33, the adjusting device 17, for the actuation of the starboard suction lifter; a comparison and calculation device 31 similarly controls a signal converter 32 _? for the operation of the suction lifter of the drainage device 16 _p on the port side.

A computing device 31 _r supplies data as reference values to both signal converters 32 _p and 32; these therefore provide information about any uneven loading and the resulting list; this information is used to act on control _{spools 33, and 33 p} for the actuating devices 17 ^ and I7 _p to operate the suction lifters on starboard and port, as explained below, to correct a list that may have arisen. If there is more sand on the starboard side than on the port side, the ship has a list to starboard, and the measured value of the pressure sensor of the draft measuring device 22 is therefore greater than the measured value of the pressure sensor of the draft measuring device 22 _p , so that the suction lift

Above the drainage device 16 on the starboard is set lower than the siphon on Port. The starboard siphon therefore protrudes deeper into the liquid than the port siphon. Because the sand concentration in the liquid is largely

When the depth is higher, the starboard siphon is used Suspension with a higher concentration of sand discharged than from the port siphon, so that the List is corrected.

In the event of overloading or an impermissible

List or both that are not adequately eliminated by the normal automatic control described a safety device 30 outputs signals to an alarm device 34 in the form of a red

309 586/34

th lamp, to an acoustic alarm device 35 and to a safety machine 36, which _{brings the suction lifters 16 p} , 16, by means of signal converters 32, and 32 _p to the lowest position, the pump 10 by means of a signal converter 37 or by means of a signal converter 38 the Unloading flaps of the unloading device 19 opens.

In order to maintain an effective device in the event of failure of the automatic control device, the automatically controlled apparatuses are also manually operated _{by means of actuators 39, 40 1} and 40 _{p, e.g.} B. from the bridge, can be actuated.

By using several pressure sensors for the draft measuring device 22 _p , 22 _C , 22, the risk of non-indication that the danger limit has been exceeded is avoided.

When sucking up a suspension with a low concentration of sand, it is conceivable that, although a large hold 12 is selected, this hold 12 is already completely filled with suspension while the suction dredger has not yet been loaded to its maximum permissible load capacity. Then the hold 12 is filled with suspension up to the point in time when the load has reached the maximum permissible load capacity of the suction dredger due to the settled sand, with water or diluted suspension running off over the upper edge of the hold 12. Only then is the further supply of additional suspension with simultaneous drainage of water with the help of the siphon of the drainage device 16 _p , 16 ,, which are controlled by means of the draft 23 and inclination indicators 29 so that the ship continues to be loaded essentially at its maximum permissible load capacity remain.

ο The suction dredger 11 also has a water pump 45, by means of which outboard water 21 is sucked in via an inlet pipe 46 and via the Lines 47 is pumped to jet mouthpieces 48, which are arranged in the lifting tubes 41 and as

ίο Jet pumps when starting the siphon effect the suction lifter of the drainage device 16 ,, 16, serve, if necessary.

After the second charging method step 14, the pump 10 can be switched off and the journey with the loaded

»5 suction dredger already started. In the following period CD while driving, the sand that is in the suspension that is still present settles. At the point in time D, all the liquid standing above the settled sand is drained off, so that the suction dredger is still loaded somewhat below its maximum permissible load capacity during the laden journey, whereby a higher speed is made possible.

If the level of the settled sand is lower

As should be as the outboard water level, can through the jet mouthpieces 48 operating as jet pumps, the liquid is also removed from this low one Level to be sucked off.

After the liquid has been sucked off, the suction cups are raised again to their upper position.

1 sheet of drawings

Claims (8)

i 956944 claims: 1. A method for loading a suction dredger with dredged material, e.g. sand, in which a water-dredged material suspension is pumped into the hold of the ship, from which dredged material is deposited, in a first loading process step the hold essentially with the water -Filled excavated material suspension and in at least one subsequent second loading process step further water-dredged material suspension is pumped into the hold and water or diluted suspension is discharged from the upper part of the hold, preferably until the suction dredger is essentially up to its largest permissible carrying capacity is loaded with deposited dredged material, characterized in that in the first loading process step (13, Fig. 2 a, 2 b) the hold is filled up to the maximum permissible carrying capacity of the suction dredger with the suspension conveyed by the suction dredger, and that in the second Charging process step (14, Fig. 2a, 2b) with the pumping of more Su The discharge of water or dilute suspension in the upper part of the hold as a function of the increase in the average cargo density is controlled in such a way that the weight ( W ₁ , F i g. 2 b) the load consisting of deposited dredged material and water or diluted suspension is kept approximately at a constant value corresponding to the maximum permissible load capacity of the suction bag. 2. suction dredger for loading according to a method according to claim 1, with a hold, a pump for supplying the water-dredged material suspension promoted by the suction dredger into the hold, a drain device for discharging water or dilute water-dredged material suspension from the upper part of the hold and with a draft measuring device, the hold volume being dimensioned larger than is required to accommodate the largest volume of dredged material corresponding to the loading of the suction dredger to its maximum permissible load capacity, characterized in that the inlet openings (43) of the drainage device (16 _p , 16,) are arranged adjustable in height, the depth _{values measured by the depth measuring device (22, 22 f} , 22,) being used to control the height-adjustable inlet openings (4.1) of the drainage device (16, 16 _t ). 3. suction dredger according to claim 2, characterized in that one or more suction lifters are provided in the hold _{as the discharge device (16 p, 16,).} 4. suction dredger according to claim 2 or 3, characterized by one of the draft measuring _{device (22L, 22 C} , 22,) controlled safety device (30) which responds when the weight ( W ₁ ) of the cargo in the hold (12) a predetermined Value exceeds. 5. suction dredger according to claim 4, characterized in that the safety device (30) causes a lowering of the inlet openings (43) of the drainage device (16 ,,, 16,). 6. suction dredger ship according to claim 4 or 5, characterized in that the safety device (30) when responding is an alarm device O4) actuated. 7. suction dredger according to claim 4 or 5, characterized in that the safety device (30) the shutdown of the pump (10) for the supply of the suspension into the hold (12) causes. 8. suction dredger according to one of claims 4 to 7, characterized in that the safety device "(30) Unloading devices (19) for removing the load from the hold (12) puts into action.