Wind turbine tower with crane connection elements and a crane with tower flange connection elements
A crane ( 2 ) comprising a base portion ( 4 ), two arms ( 6, 8 ) displaceably connected to the base portion and a lifting boom ( 22 ) displaceably connected to the base portion, said lifting boom being provided with a lifting wire ( 32 ) and a lifting member ( 30 ), for example a lifting hook, for lifting a load, wherein the two arms and the base portion in combination comprise at least three tower flange connection element ( 10 ) is arranged to be detachably connectable to cooperating crane connection elements on a flange of a wind turbine tower section, wherein each arm comprises one of the tower flange connection elements, and wherein the vertical distance between any two tower flange connection elements in the normal operating position of the crane is less than 1 m, less than 50 cm or less than 25 cm. In this way a crane is provided which can be attached to a flange located at the upper portion of a tower section.
1. A crane comprising a base portion, two arms displaceably connected to the base portion and a lifting boom displaceably connected to the base portion, said lifting boom being provided with a lifting wire and a lifting member, for lifting a load, wherein
a. the two arms and the base portion in combination comprise at least three tower flange connection elements arranged to be detachably connectable to cooperating crane connection elements on a flange of a wind turbine tower section,
b. each arm comprises one of the tower flange connection elements, and
c. a vertical distance between any two tower flange connection elements in the normal operating position of the crane is less than 1 m, wherein
each of the two arms comprise two of the at least three tower flange connection elements, and
the tower flange connection elements of the two arms are arranged on essentially the same horizontal plane.
2. The crane according to claim 1 , wherein the vertical distance between any three of the at least three tower flange connection elements is less than 50 cm.
3. The crane according to claim 1 , wherein the crane further comprises a wire and pulley system comprising the lifting wire and the lifting member.
4. The crane according to claim 3 , wherein the wire and pulley system comprises a lower pulley block comprising a pulley and an upper pulley block comprising at least one more pulley than the lower pulley block, the upper pulley block comprising the lifting member and the lower pulley block comprising a first connection element suitable for establishing a detachable connection to the lifting member and a second connection element suitable for establishing a detachable connection to a crane hoisting connection element arranged on a tower section of a wind turbine tower when the crane is connected to a tower section.
5. The crane according to claim 1 , wherein the crane further comprises a moment compensating mechanism comprising a moment compensating arm which is at least 300 cm long and which extends out from the crane with a horizontal component, an end of said arm being connected via a wire to a winch located remotely from the crane.
6. The crane according to claim 1 , wherein a length of the lifting boom is such that a vertical distance between a highest location of the lifting member and the tower flange connection elements is greater than 5 m, greater than 10 m or greater than 20 m.
7. The crane according to claim 6 , wherein said vertical distance is greater than a height of a tower section of the wind turbine tower section.