US3611595A - Suction dredger and method of suction dredging - Google Patents

Suction dredger and method of suction dredging Download PDF

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Publication number
US3611595A
US3611595A US3611595DA US3611595A US 3611595 A US3611595 A US 3611595A US 3611595D A US3611595D A US 3611595DA US 3611595 A US3611595 A US 3611595A
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US
United States
Prior art keywords
suction
pipe
water
sand
suction pipe
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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English (en)
Inventor
Jan De Koning
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ingenieursbureau voor Systemen en Octrooien Spanstaal BV
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Ingenieursbureau voor Systemen en Octrooien Spanstaal BV
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Publication of US3611595A publication Critical patent/US3611595A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/88—Dredgers; Soil-shifting machines mechanically-driven with arrangements acting by a sucking or forcing effect, e.g. suction dredgers
    • E02F3/90—Component parts, e.g. arrangement or adaptation of pumps
    • E02F3/907—Measuring or control devices, e.g. control units, detection means or sensors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/0318—Processes
    • Y10T137/0324—With control of flow by a condition or characteristic of a fluid
    • Y10T137/0329—Mixing of plural fluids of diverse characteristics or conditions
    • Y10T137/0335—Controlled by consistency of mixture
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/2496—Self-proportioning or correlating systems
    • Y10T137/2499—Mixture condition maintaining or sensing
    • Y10T137/2506—By viscosity or consistency

Definitions

  • This invention relates to a suction dredger installation comprising a pump and a suction pipe which is connected to the pump and which has at least one first suction nozzle at the end and at least one second suction nozzle between the pump and the end.
  • the invention also relates to a method of sucking up spoil by means of the said suction dredger installation, wherein the first suction nozzle draws spoil and the second suction nozzle draws mainly water into the suction pipe.
  • a suction dredger of this kind and a method of this kind are disclosed in German patent specification 815,625.
  • This specification proposes so to construct the end of the suction pipe that the second suction nozzle can draw a considerable amount of water, more particularly if the first suction nozzle becomes clogged by large objects, i.e., large stones or rocks.
  • the first suction nozzle is held above the cavity while the attempt is made to obtain a constant spoil concentration in the drawn-up suspension.
  • it is very difiicult to obtain this constant concentration because the condition in front of the first suction nozzle are continuously subject to considerable variation.
  • the invention provides a method and a suction dredger installation of the type specified in the first paragraph, with considerable advantages over the prior art.
  • the end of the suction pipe is inserted into the cavity and the distance between the two suction nozzles is adjusted to control the concentration of spoil in the drawn-in suspension in dependence upon the column of spoil and any other material fioating thereon above the first suction nozzle.
  • the spoil concentration in the sucked up suspension is thus accurately adjusted to the required value.
  • An important advantage of the method according to the invention is that it can be used to draw spoil from the cavity even beneath an impure top layer, for example a layer of clay.
  • the impurities and large objects at the bottom of a dredging site cannot ClOg the suction nozzles with the method according to the invention.
  • the end of the suction pipe is inserted deeply into the cavity so as to reduce the risk of the impure top layer reaching the suction nozzle. Drawing spoil from a deep position beneath the cavity does not require more power than drawing spoil at the surface of the cavity.
  • the invention also provides a suction dredger installation adapted more particularly to performing the method according to the invention and which is characterized by adjustability of the distance between the two suction nozzles.
  • the invention provides a number of advantageous constructions of the suction pipe end, the distance between the two suction nozzles being adjustable, while the position of the first suction nozzle and the suction pipe with respect to the hard cavity can be maintained.
  • FIG. 1 is a diagrammatic view of the surroundings of the end of a suction pipe during performance of the method according to the invention.
  • FIG. 6 is a diagrammatic View illustrating the component parts of the suction dredger installation according to the present invention.
  • the suction dredger installation includes a suitable pump 20 having a discharge line 21 from which a fluid suspension of water and sand is obtained. It will be understood that the suction dredger installation may be mounted, for example, on a barge or the like with the barge receiving the material discharged.
  • the inlet side of the pump is connected to the conduit system indicated by the reference character 22 which leads to the suction pipe 23 which, at its lower end as will hereinafter be more particularly pointed out, is adapted to withdraw the spoil or sand into the conduit system.
  • a separate inlet for water is provided into the conduit system and the level at which the separately introduced water is comingled with the suspension of an inherently high sand concentration is controlled to produce the desired and much lower sand concentration reaching the discharge line 21.
  • the control for adjusting the point of water introduction is indicated by the reference character 24 and may take any suitable form compatible with the mechanism actually utilized for adjusting the water level intake.
  • the concentration of sand in the suspension be maintained in the range of about 10 to about 25%. Within this range, good pumping efi"1 ciency is obtained while at the same time effecting an efficient and essentially continuous withdrawal of sand or spoil from the bed of material being dredged.
  • the suction dredger installation used has a suction pipe whose end dilfers from conventional constructions.
  • the figures show only the free part of the suction pipe of the suction dredger installation which comprises a spoil pump between a pressure pipe and a suction pipe.
  • the suction pipe 3 which is shown in the operative position in FIG. 1, comprises a first suction nozzle 1 and a second suction nozzle formed by opening one of the apertures 211-2p. These apertures are at different distances from suction nozzle 1 and normally each one is closed by a slide 4. Each slide 4 can be remotely adjusted independently by suitable means, i.e., hydraulic means, between two positions in which the opening is respectively open and closed.
  • FIG. 1 also shows the following in the upward direction: a layer of sand 6, a layer of clay 7, impurities, i.e. wood, 8, resting on the layer of clay, and water 9.
  • the soil enclosed by line is brought into suspension by undermining while outside the line 10 the soil is consolidated.
  • aperture 2m is left open so that at that aperture the incoming water and the suspension drawn through the first aperture 1 are mixed with a very high sand concentration.
  • the high-concentration suspension rises automatically to the level of the aperture 2m in the suction pipe because the end of the suction pipe forms a communicating vessel with the cavity in the consolidated soil indicated by line 10. It will be immediately apparent that if aperture 2 for example, were opened, the suspension would run out of the suction pipe into the water. The water would thus be prevented from entering through such aperture, so that the pump would draw only spoil with a very high concentration. This would result in stalling of the pump and sand clogging of the suction pipe, pump and/or pressure pipe.
  • the sand concentration in the suspension can be controlled and the pumping power can be applied with maximum economy.
  • Sand is preferably drawn deeply from the cavity. This greatly reduces any chance of impurities or clay being drawn in.
  • the fact that sand is drawn in from a low level does not require more energy than if it were drawn from the level of the impurities 8.
  • the dredged well is not first freed of clay and impurities; instead, the weight of clay and impurities is put to advantage for drawing in the sand. Neither the drawing of sand to the aperture 2m nor the conveying of water to the suction pipe 3 requires energy.
  • a water pipe 111 is preferably disposed around the suction pipe 103, the water pipe being closed at the bottom and open at the top, see FIG. 2. This water pipe always provides communication between the open second suction nozzle 102a-102p, and the water above the dredging site. Otherwise, the construction and operation of the suction pipe of FIG. 2 in the same as that of the suction pipe of FIG. 1.
  • the pressure difference acting on the sand at the sand inlet and causing it to flow upwardly is determined by the weight of the column h of sand, clay and impurities above the first section nozzle 1. This pressure difference is cancelled out by adjusting the second suction nozzle 2 to approximately the level of the top of the column 11. Adjustment of the second suction nozzle to a higher or lower level respectively results in more water and more sand being pumped up.
  • the concentration of sand in the suspension can be accurately controlled by continuous variation of the distance between the first and second suction nozzles.
  • FIG. 3 shows a suction pipe 203 with a continuously variable distance between the first suction nozzle 201 and the second suction nozzle 202.
  • the second suction nozzle 202 is formed by one or more slots in the suction pipe completely closed by means of slide 204 engaging around the suction pipe 203.
  • This slide is remotely adjustable by a hydraulic cylinder provided between the water pipe 211 and the slide 204.
  • the level of the second suction nozzle is determined by the level of the bottom end of the slide 204.
  • the suction nozzle 303 shown in FIG. 4 is substantially the same as that shown in FIG. 3.
  • the suction pipe 303 consists of four parts, i.e., a pipe part 303a rigidly connected to the pump, a part 3031) axially slidable with respect to the fixed part 303a, a part 303a having a larger diameter and integral with the pipe 311 disposed around the suction pipe 303 and a pipe part 303d having a same diameter as pipe part 303b and being connected by means of a basket 304 to the end of the pipe part 303a.
  • first nozzles 301a and 30112 are provided in the lower end of the pipe parts 303d and 3030 respectively, while the water inlet is formed by an annular gap between the water pipe 311 and the bottom end of the slidable part 3033b.
  • the latter part is guided by three wheels, 313, which are distributed over the periphery, with respect to the water pipe 311 secured to the fixed part 303a.
  • the part 3031 is adjusted by means of three hydraulic cylinders 312 distributed over the periphery.
  • adjustment of the distance between the first nozzle 30111 and the water inlet is obtained automatically.
  • the means for operating the slides, or valves, 4 and/or the slidable part 303b can be controlled by the concentration meter incorporated in the suction pipe or pressure pipe.
  • the slidable part While the end of the suction pipe 303 is introduced into the cavity the slidable part is preferably pushed down until it abuts the portion 303d. A continuous pipe with just one aperture 301a is thus formed.
  • the suction pipe can thus be used firstly as an injection lance and then as a suction pipe 303 with just a first suction nozzle 301a if the cavity is still hard or consolidated. In this way the suction pipe can be introduced into the cavity more easily at the beginning of the suction process.
  • the second suction nozzle 301b can be formed by pulling up the part 303k. In this way the first suction nozzle 301a is simultaneously opened, through which further the main volume of the drawn up suspension enters into the suction pipe.
  • the preferred embodiment of the suction pipe is shown in FIG. 5 and ditfers from the suction pipe 303 by the facts that a ring 415 having a central aperture in which the pipe part 4031: just slidably fits, is arranged above the basket 414, the pipe part 403d is shortened at its top and the pipe part 403! is lengthened at its lower end.
  • the suction pipe again is provided with two first nozzles, the one 401a of which is positioned in the lower end of the pipe part 403d and the other 40112 of which is positioned like an annular gap between the upper end of the pipe part 403d and the ring 415.
  • This suction pipe can be put in the cavity even more easy.
  • the slidable pipe part 403k is slided downwards until it abuts the pipe part 403d and the suction pipe is alternatively used as an injection lance and as a suction pipe having only one first nozzle 401a as long as the cavity in front of the nozzle is still consolidated.
  • the water inlet is adjusted at such a height above the first nozzle 30111 or 401a respectively that the pressure at the inside of the spoil inlets is not much lower than on the outside. This prevents any clogging of any of the spoil inlets or at least greatly reduces the chance of disturbing clogging. Since the end of the suction pipe is inserted into the cavity and moved along in good time, the spoil of the cavity is loosened by undermining and prepared as a readily dredged suspension having a high spoil concentration.
  • the suction at the spoil inlet which is principally the cause of clogging in conventional methods, can be small in the method of the invention, firstly because the suction nozzle is continuously kept in a suspension having a high spoil concentration instead of in front of a cavity which has to be worked loose, and secondly because a small part of the total flow of the suspension is fed through the spoil inlets.
  • the water, which forms the greater part of the flow through the pump, does not enter the suction pipe via the suspension inlets.
  • turbulent flow occurs as a result of the spoil currents through the other spoil inlets and as a result of the movements of the suction pipe which take place periodically or continuously, and these turbulent currents have an opposite direction at the covered inlet; in other words, a pressure difference occurs over the covered inlet and is opposed to the small pressure difference normally prevailing over such inlet and even outweighs such pressure difference. Consequently nearly every object is detached from the inlet in question and drops behind the pipe.
  • the pipe part 3031) or 4013b may be lifted periodically so that every time such lifting occurs the suction at the spoil inlets is decreased.
  • a cutter may be provided at the end of the suction pipe to loosen the hard cavity immediately in front of the first suction nozzle.
  • the meshes of the basket 314 or 414 respectively are preferably constructed in the form of tubes which are connected to a water pump and which at the end adjacent the hard cavity are provided with exit apertures for water under pressure. If this basket strikes against the hard cavity the meshes make their own path therethrough and thus undermine the sand and clay above the basket.
  • a method of suction dredging sand which comprises the steps of:
  • the method according to claim 2 including the steps of measuring the concentration of particulate material in the mixture being withdrawn through the pipe above said point at which the particulate material and water are commingled, and controlling the location of said point in response to the concentration measured.
  • a suction dredger installation comprising a pump and a suction pipe having an upper end connected to said pump and which has at least one first nozzle for spoil at its lower end and at least one second nozzle mainly for water between the pump and said. lower end, and means for adjusting the level of said second nozzle independently of the levels of said upper end of the suction pipe and of said first nozzle to vary the distance between the two nozzles;
  • said suction pipe comprising inner and outer pipe sections, said outer section having an open lower end forming said first nozzle and said inner section having an open lower end forming said second nozzle with the surrounding wall of said outer section, said means being connected to said inner section to axially shift same within said outer section;
  • a sleeve carried at the lower end of said outer section beyond the opening of the latter, said sleeve being aligned with said inner section for engagement by the lower end thereof.
  • a suction dredger installation comprising, in combination:
  • a suction pump adapted efiiciently to induct and discharge fluid suspensions of sand in water having selected values of sand concentration therein, and having an inlet for inducting such suspensions;
  • suction pipe means connected to said inlet and having an open lower end adapted to be inserted deeply into a body of sand below the level of the bottom of a body of water so that a first column of sand and water tends to form in said suction pipe means due to the static head on the sand, in which the concentration of sand in said first column is much greater than said selected values;
  • suction pipe means comprises a first pipe directly connected to said inlet of the pump, an outer jacket surrounding said first pipe and having an opening above said first column for admitting water thereinto, and a second pipe slidably engaging said first pipe; and wherein said means for adjusting comprises an actuator for moving said second pipe relative to said first pipe.
  • suction dredger installation including a nozzle fixed at and projecting from said lower end of said suction pipe means, said second pipe being aligned with said nozzle for engagement therewith so that said jacket may be isolated from said first pipe.
  • suction pipe means comprises a first pipe directly conected to said inlet of the pump, and an outer jacket surrounding said first pipe and having an opening above said first column for admitting water thereinto, and wherein said means for introducing water comprises opening means along the length of said first pipe.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Jet Pumps And Other Pumps (AREA)
US3611595D 1965-02-04 1969-08-08 Suction dredger and method of suction dredging Expired - Lifetime US3611595A (en)

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NL6501404A NL6501404A (en)van) 1965-02-04 1965-02-04

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909960A (en) * 1973-05-29 1975-10-07 Univ Hawaii Loose material recovery system having a mixing box
US4020573A (en) * 1974-02-25 1977-05-03 Ballast-Nedam Group N.V. Method and device for sucking up a solid substance from a stock
US4470208A (en) * 1981-10-22 1984-09-11 Hendrikus Van Berk Dredge with adjustable bottom support for suction pipe and method
US5428908A (en) * 1993-03-09 1995-07-04 Kerfoot; William B. Apparatus and method for subsidence deepening
CN111648463A (zh) * 2020-05-29 2020-09-11 福建德超建设工程有限公司 一种市政工程用下水管道底层淤泥处理装置

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL145919B (nl) * 1967-05-24 1975-05-15 Spanstaal Zuigbaggerinstallatie.
NL147218B (nl) * 1967-10-16 1975-09-15 Spanstaal Werkwijze en zuigbaggerinstallatie voor het opzuigen van baggerspecie.
NL6714007A (en)van) * 1967-10-16 1969-04-18
NL6714009A (en)van) * 1967-10-16 1969-04-18
NL6803191A (en)van) * 1968-03-06 1969-09-09

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909960A (en) * 1973-05-29 1975-10-07 Univ Hawaii Loose material recovery system having a mixing box
US4020573A (en) * 1974-02-25 1977-05-03 Ballast-Nedam Group N.V. Method and device for sucking up a solid substance from a stock
US4470208A (en) * 1981-10-22 1984-09-11 Hendrikus Van Berk Dredge with adjustable bottom support for suction pipe and method
US5428908A (en) * 1993-03-09 1995-07-04 Kerfoot; William B. Apparatus and method for subsidence deepening
CN111648463A (zh) * 2020-05-29 2020-09-11 福建德超建设工程有限公司 一种市政工程用下水管道底层淤泥处理装置

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