Cutter head with suction function and a method for using same

Abstract

The invention relates to a cutter head for removing a mixture comprising water and solid materials from a water bottom, comprising rotating blades each provided with cutting means on a leading edge thereof, said cutter head being rotatably coupled to a tube for transporting said mixture, the shape of the leading edge of said rotating blades being defined by substantially fitting a rounded cone with a rotation axis, wherein each rotating blade at a middle part is coupled to a connecting ring and at a top part is linked to a top part of another rotating blade. The cutter head is characterized in that the rotation axis of said blades is substantially aligned with a rotation axis of said ring; in that a trailing edge of part at least one of said blades is positioned closer to said rotation axis than a leading edge of said blades so as to provide a suction function towards said tube upon rotation of said cutter head; and in that said blades as viewed from said top part at a bottom part of said blades extend to a position beyond said connecting ring. A preferred embodiment comprises a method for using the cutter head according to the invention.

Claims

1. A cutter head for removing a mixture comprising water and solid materials from a bottom of a body of water, comprising rotating blades each provided with cutting means on a leading edge thereof, said cutter head being rotatably coupled to a tube for transporting said mixture, the shape of the leading edge of said rotating blades being defined by substantially fitting a rounded cone with a rotation axis, wherein each rotating blade at a middle part is fixedly coupled to a single connecting ring and at a top part is linked to a top part of another rotating blade, wherein the single connecting ring is positioned at an outer circumference of the rotating blades; wherein the rotation axis of said blades is aligned with a rotation axis of said single connecting ring; wherein a trailing edge of part of at least one of said blades is positioned closer to said rotation axis than a leading edge of said blades so as to provide a suction function towards said tube upon rotation of said cutter head; and wherein said blades as viewed from said top part at a bottom part of said blades extend to a position beyond said connecting ring and are positioned partly inside the tube; and wherein said single connecting ring is coupled to the tube, the tube and the single connecting ring rotating coaxially with respect to rotation of said blades.

2. The cutter head according to claim 1, wherein said leading edge of said blades is directed substantially into a rotation direction of said blades.

3. The cutter head according to claim 1, wherein said leading edges of said blades substantially fit said rounded cone.

4. The cutter head according to claim 1, wherein said rotating blades comprise a guiding surface between said leading edge and said trailing edge and directed towards a position between said cone and said rotation axis.

5. The cutter head according to claim 1, wherein a trailing edge of said blades near said middle part is positioned at a larger distance from said rotation axis than a trailing edge of said blades near said top part.

6. The cutter head according to claim 1, wherein a trailing edge of said blades near said middle part is positioned at a larger distance from said rotation axis than a trailing edge of said blades near said bottom part.

7. The cutter head according to claim 1, wherein a trailing edge of at least one of said blades at a position near said middle part is positioned closer to said rotation axis than a leading edge of at least one of said blades at a position closer to said top part.

8. The cutter head according to claim 1, wherein said single connecting ring and said tube are connected and jointly rotatably driven.

9. The cutter head according to claim 8, wherein said tube is driven by means of a coaxial motor positioned at an outside of said tube.

10. A method of dredging a water bottom by using a cutter head according to claim 1, the method comprising the steps of positioning said cutter head on said water bottom, and rotatably driving a mutually connected tube and said cutter head so as to cut the water bottom and pumping an obtained mixture of solids and water through said tube.

Description

(1) Hereafter, the invention will be further described by means of a drawing. The drawing shows in:

(2) FIG. 1 a partially sectional side view of a cutter head according to the invention;

(3) FIG. 2 shows a perspective bottom view of the cutter head according to FIG. 1; and

(4) FIG. 3 shows a top view of the cutter head according to FIG. 1.

(5) The same and similar parts and features of the cutter head according to the present invention have been denoted by the same reference numerals in the figures. However, for ease of understanding the figures, not all parts that are required for a practical embodiment have been shown.

(6) FIG. 1 shows a partially sectional side view of a cutter head 1 for dredging purposes and the like in a water bottom. The cutter head 1 comprises blades 2 to which cutting means 3 are provided for cutting the water bottom. During use, the cutter head 1 is rotated along rotation axis 4 so as to consecutively cut the water bottom by means of said cutting means 3. Generally, cutter heads 1 as shown in the figure are used in dredging for removing sand, rocks and the like from a water bottom. Therefore, a mixture of solid materials and water is obtained, that must be removed from said water bottom.

(7) The blades 2 in the cutter head 1 according to the present invention are embodied somewhat helicoid. A plurality of blades 2 is provided, positioned symmetrically around a rotation axis 4. Each only covers part of a circle if viewed from a position on its rotation axis 4, as schematically shown in FIG. 2. Preferably, each blade 2 is embodied with a rake and skew. As a consequence, the blades 2 are mutually coupled at a first position 5 close to the rotation axis 4, whereas at a second position 6 each blade 2 is connected to a rim 7 (in this description also mentioned connecting ring 7), said second position 6 being further away from the rotation axis 4.

(8) In between said two positions 5, 6, each blade 2 provides a pumping action upon rotation of the cutter head 1, said pumping action being dependent on the rate of rake and skew, the diameter of the blades 2 and the rotational velocity of the cutter head 1.

(9) The blades 2 are coupled to a tube 8, preferably through said rim 7. A rotation axis 9 of said tube 8 is aligned with the rotation axis 4 of said set of blades 2.

(10) Due to the shape of the blades 2, a pumping action is obtained upon rotation of the blades 2. A leading edge 10 is directed into the rotational direction of the cutter head 1 whereas the blades 2 are shaped such that a trailing edge 11 is directing to and situated in a location inside the circumference of the rim 7 of the cutter head 1. As a matter of fact, the trailing edge 11 of each blade is located closer to the rotation axis 4 than the leading edge 10 at a same distance from the rim 7. The blade 2 may bend progressively from the leading edge 10 towards the trailing edge 11, but a uniform bending is possible as well. The pumping action induced by the blades 2 on the mixture of water and solids is dependent on such shape of the blades 2. Furthermore, due to the shape of the blades 2, mixture of water and solid materials is directed towards the inside of the cutter head 1 and therefore directly towards the tube 8, such that all mixture will be transported efficiently. As a consequence, the pumping head provided by the shape of the blades 2 of the cutter head 1 work together with the propelling action of the said blades 2 such that a most efficient effect is obtained. It has shown that the pumping head provided by the cutter head of the present invention may increase significantly. This relieves the regular pump or may even allow shutting off the regular pump. A huge advantage is the cost reduction for pumping gear, if compared with the state of the art.

(11) As shown in FIG. 1, the cutting means 3 are provided on the leading edge 9 of each blade 2.

(12) As mentioned above, FIG. 1 shows a partly sectional side view of the cutter head 1. The rake and skew of each blade 2 are clearly visible in FIG. 1 and also in FIGS. 2 and 3.

(13) The top view of FIG. 2 clearly shows that the blades 2 are mutually connected at first position 5. A connecting member 13 is provided to which all blades 2 are connected at their respective top part.

(14) FIG. 3 clearly shows that part 12 of blades 2 extend to a position beyond the rim 7, if viewed from the first position 5. Part of the blades 2 is placed between said first position 5 and the rim 7 (i.e. second position 6), whereas a remaining part 12 of said blades 2 extend further. It is clear from FIG. 1 that said part 12 is placed inside the tube 8. As a consequence, the mixture of water and solid material is effectively guided into the tube 8. It is not necessary that part 12 also provides a pumping action. It may be sufficient for part 12 to guide said mixture into the tube 8, although some additional pumping action provided by part 12 may help to more effectively transport said dredged mixture.

(15) The invention is not limited to the embodiments as mentioned above and as shown in the drawings. The invention is limited by the claims only.

(16) The invention also relates to all combinations of features described here independently of each other.