Suction dredging installation

Claim 2

Suction dredging installation comprising a suction pipe which is connected to a pump and which has a suction opening at its end and a throat between the pump and the suction opening, in which the nominal flow section of the suction pipe has substantially a same value from the throat to the pump, whereas the flow section of the suction opening is larger tHan said nominal flow section, characterised in that the part of the suction pipe with the nominal flow section at the location of the throat is provided with a collar which extends radially outwards, and in that the part of said suction pipe, extending from the suction opening to the throat, has substantially said large flow section of the suction opening said part of the suction pipe with nominal flow section being eclosed by a water pipe which has the same diameter as the part of the suction pipe extending under the throat and which is connected via an annular gap along the outer edge of the collar to the part of the suction pipe extending under the throat.

Claim 3

Suction dredging installation according to claim 1, characterised in that at least one pipe for water under pressure is attached to the sliding pipe, which pipe for water under pressure communicates at its lower end via the annular gap with the suction pipe.

Claim 4

Suction dredging installation comprising a suction pipe which is connected to a pump and which has a suction opening at its end and a throat between the pump and the suction opening, in which the nominal flow section of the suction pipe has substantially a same value from the throat to the pump, whereas the flow section of the suction opening is larger than said nominal flow section, characterised in that the part of the suction pipe with the nominal flow section at the location of the throat is provided with a collar which extends radially outward, and in that the part of said suction pipe, extending from the suction opening to the throat, has substantially said large flow section of the suction opening the suction pipe comprising an inner pipe, a sliding pipe disposed at the lower end of the inner pipe and telescopically co-operating therewith, a jacket enclosing the inner pipe and the sliding pipe and drive means for driving the sliding pipe, the sliding pipe having at its lower end the throat.

Claim 5

Suction dredging installation comprising a suction pipe which is connected to a pump and which has a suction opening at its end and a throat between the pump and the suction opening, in which the nominal flow section of the suction pipe has substantially a same value from the throat to the pump, whereas the flow section of the suction opening is larger than said nominal flow section, characterised in that the part of the suction pipe with the nominal flow section at the location of the throat is provided with a collar which extends radially outward, and in that the part of said suction pipe, extending from the suction opening to the throat, has substantially said large flow section of the suction opening the suction pipe comprising an inner pipe, a sliding pipe disposed at the lower end of the inner pipe and telescopically co-operating therewith, a jacket enclosing the inner pipe and the sliding pipe and drive means for driving the sliding pipe, the sliding pipe having at its lower end the throat.

Claim 6

In a dredging installation for suction dredging sand and the like from beneath a body of water, the combination of: suction pipe means presenting a suction mouth and adapted to be connected at its upper end to a suction pump so as to induct a mixture of sand and water through said suction mouth, said suction pipe means also presenting a throat between said upper end thereof and said suction mouth, said suction pipe means being of substantially uniform cross-sectional area upwardly from said throat and being of substantially uniform but larger cross-sectional area from said suction mouth to said throat whereby to present an abrupt cross-sectional area reduction at said throat; and means for introducing secondary water into said suction pipe means immediately below said throat to form vortex flow in the region of transition between said larger and smaller cross-sectional areas at said throat, whereby to minimize the inflow losses at the suction mouth.

Claim 7

In a dredging installation for suction dredging sand and the like from beneath a body of water, the combination of: suction pipe means presenting a suction mouth and adapted to be connected at its upper end to a suction pump so as to induct a mixture of sand and water through said suction mouth, said suction pipe means also presenting a throat between said upper end thereof and said suction mouth, said suction pipe means being of substantially uniform cross-sectional area upwardly from said throat and being of substantially uniform but larger cross-sectional area from said suction mouth to said throat whereby to present an abrupt cross-sectional area reduction at said throat; and means for introducing secondary water into said suction pipe means immediately below said throat to form vortex flow in the region of transition between said larger and smaller cross-sectional areas at said throat, whereby to minimize the inflow losses at the suction mouth.

Claim 8

In a dredging installation as defined in claim 4 wherein said suction pipe means includes an upper pipe section and a sliding pipe section extensible below the upper pipe section and presenting said throat at its lower extremity, an enlarged pipe portion fixed to said sliding pipe section and enclosing said lower extremity so as to project above and below said throat and presenting an annular passage for secondary water between the sliding pipe section and said enlarged pipe portion above said throat, a radially outwardly projecting collar fixed to said lower extremity of said sliding pipe section around said throat and defining opening means between it and said enlarged pipe section in surrounding relation to said throat, said collar defining said abrupt cross-sectional area reduction at said throat, and said annular passage and opening means forming part of said means for introducing secondary water.

Claim 9

In a dredging installation as defined in claim 5 wherein said suction pipe means also includes a jacket for secondary water surrounding said sliding pipe section and having a reduced tubular Lower end portion aligned therewith and presenting said suction mouth, said enlarged pipe portion being dimensioned for close sliding fit within said reduced tubular lower end portion.

Claim 10

In a dredging installation as defined in claim 6 wherein said means for introducing secondary water includes conduit means for introducing secondary water under pressure into said jacket.

Claim 11

In a dredging installation for suction dredging sand and the like from beneath a body of water, the combination of: an outer jacket having a reduced tubular lower end portion defining a suction mouth at its lower extremity; a sliding pipe adapted to be connected to a suction pump, said sliding pipe having a cross-sectional area substantially smaller than the cross-sectional area of said tubular lower end portion of said jacket and defining a throat at its lower extremity; means mounting said sliding pipe within said jacket in concentric alignment with said tubular lower end portion of the jacket; an enlarged pipe portion fixed in concentric relation to said sliding pipe, said pipe portion extending above and below said throat to present an annular passage between it and the sliding pipe which extends above said throat and communicates with the interior of said jacket, said pipe portion being dimensioned to fit in close sliding relation within said tubular lower end portion of said jacket; a strainer at the lower end of said pipe portion; a collar projecting radially outwardly from the lower extremity of said sliding pipe toward said pipe portion and defining opening means therewith lying in surrounding relation to said throat; and means for introducing secondary water into said jacket while a mixture of sand and water is flowing through said suction mouth into said throat whereby secondary water flows from said jacket through said annular passage and said opening means to form an annular vortex immediately below said collar and surrounding the area beneath said throat.

Claim 12

In a dredging installation for suction dredging sand and the like from beneath a body of water, the combination of: an outer jacket having a reduced tubular lower end portion defining a suction mouth at its lower extremity; a sliding pipe adapted to be connected to a suction pump, said sliding pipe having a cross-sectional area substantially smaller than the cross-sectional area of said tubular lower end portion of said jacket and defining a throat at its lower extremity; means mounting said sliding pipe within said jacket in concentric alignment with said tubular lower end portion of the jacket; an enlarged pipe portion fixed in concentric relation to said sliding pipe, said pipe portion extending above and below said throat to present an annular passage between it and the sliding pipe which extends above said throat and communicates with the interior of said jacket, said pipe portion being dimensioned to fit in close sliding relation within said tubular lower end portion of said jacket; a strainer at the lower end of said pipe portion; a collar projecting radially outwardly from the lower extremity of said sliding pipe toward said pipe portion and defining opening means therewith lying in surrounding relation to said throat; and means for introducing secondary water into said jacket while a mixture of sand and water is flowing through said suction mouth into said throat whereby secondary water flows from said jacket through said annular passage and said opening means to form an annular vortex immediately below said collar and surrounding the area beneath said throat.

Claim 13

In a dredging installation for suction dredging sand and the like from beneath a body of water, the combination of: suction pipe means having an open lower end presenting a suction mouth and adapted to be connected at its upper end to a suction pump so as to induct a mixture of sand and water through said suction mouth, said suction pipe means also presenting a throat between said upper end thereof and said suction mouth, said suction pipe means being of substantially uniform cross-sectional area upwardly from said throat and being of substantially uniform but larger cross-sectional area from said suction mouth to said throat; and means defining an abrupt cross-sectional area reduction at said throat for forming an annular vortex surrounding the area immediately below said throat, whereby to minimize inflow losses at said suction mouth.

Claim 14

In a dredging installation for suction dredging sand and the like from beneath a body of water, the combination of: suction pipe means having an open lower end presenting a suction mouth and adapted to be connected at its upper end to a suction pump so as to induct a mixture of sand and water through said suction mouth, said suction pipe means also presenting a throat between said upper end thereof and said suction mouth, said suction pipe means being of substantially uniform cross-sectional area upwardly from said throat and being of substantially uniform but larger cross-sectional area from said suction mouth to said throat; and means defining an abrupt cross-sectional area reduction at said throat for forming an annular vortex surrounding the area immediately below said throat, whereby to minimize inflow losses at said suction mouth.