Background of the invention When taking samples from a floor under a body of water it is essential that the sample is protected and persevered as the sample may be subject to determinations and investigations of the character of the layers in the material of the floor.

Methods and apparatuses for taking samples already exist and comprises a pipe adapted to take samples from the floor. When a sample is to be taken the pipe is placed in a frame structure comprising an impact generating device designed to drive to pipe into the floor.

In known methods and apparatuses the impact generating device is placed on top of the pipe so as to drive the pipe into the floor.

The known methods and apparatuses have several disadvantages. When the generating device is placed on top of the pipe the vibrations generated must be transmitted from the top of the pipe, where the generating device is placed, to the part of the pipe already driven into the floor so as to drive the pipe further into the floor. This implied oscillations in the longitudinal direction of the pipe, thus resulting in a low coefficient of utilisation of the energy supplied to the device. Furthermore placing the generating device on the top of the pipe implies that the pipe can not be extended during operation of the device. When taking a sample it is desirable to be able to extend the pipe as the conditions of the floor from which the sample is to be taken may not be known prior to initiate the process.

It is an object of the present invention to find solutions to the problems described above.

The methods and apparatuses according to the present invention shall make extension of bodies for taking samples of a floor under a body of water possible preferably during operation of the generating device. Furthermore the methods and apparatuses according to the present invention shall apply the impact to the elongated body at a point on said body, said point being as close to the floor as possible, so as to increase the utilisation of the energy applied to the elongated body as oscillation in the part of the elongated body not driven into the floor is minimised.

Description of the invention Thus, the present invention provides a method for driving an elongated body into a floor under a body of water, said method comprising - arranging a vibration or impact generating device on the body, said device being spaced above the floor surface, - driving the body into the floor by activating the vibration and/or impact generating device and - moving the vibration or impact generating device along the elongated body so as to maintain the generating device spaced above the floor surface, when the longitudinally extending body is driven into the floor.

In an embodiment of the invention the device is placed on the elongated body so that the device is placed right above the floor, i. e. as close to the floor as possible without touching the floor. The advantage thereof is that the part of the elongated body being compressed, when the impact or vibration generating device is activated, is minimised, as the part of the elongated body being placed above the device is not compressed during operation of the device. The result is that the amount of energy being transformed into heat energy due to oscillation is reduced. Thereby the efficiency of the device is increased.

Furthermore the advantage of placing the device on the side of the elongated body is that the elongated body can be extended during operation of the device. In conventional systems and methods the device is placed on top of the elongated body and therefore the body can not be extended during operation of the device. Instead the device will have to be stopped and removed so that the elongated body can be extended. The disadvantage thereof is that the process of driving the elongated body into the floor is stopped and may not be possible to continue due to an increased friction between the elongated body and the material of the floor. The increased friction arises due to the fact that the static friction is higher than the dynamic friction between the elongated body and the material of the floor.

If the elongated body is adapted to take samples from the floor the static friction between the sample already taken (when the device is stopped) and the elongated body may turn the sample into a plug thus blocking the elongated body and preventing that further sampling.

The invention may be configured so that the device is moved along the elongated body for maintaining the generating device spaced above the floor surface, when the longitudinally

extending body is driven into the floor. The advantage hereof is that the part of the elongated body being compressed during operation of the device is minimised resulting in the previously mentioned advantages. The distance between the device and the floor surface may also change during operation of the device so as to optimise the penetration of the material of the elongated body. The optimisation may be achieved by performing an analysis of the hardness of the floor material e. g. by performing a cone penetration test and subsequently use the result of said analysis to optimise the sample taking. The two steps may also be united into one step where determination of the hardness of the material from where samples are taken is determined during the sample taking.

The elongated body may be a tubular body such as a cylindrical, preferably a circular cylindrical body. In an embodiment the elongated body is adapted to take samples from the floor and thus further comprises a separate lining tube for preserving a sample from the floor. A new separate lining tube may be used for each sampling of the floor. The advantage thereof is that the separate lining tube can serve as a cover for the sample when the sample is elevated to a position above the body of water e. g. above the sea level. After taking the sample the separate lining tube can be cut into pieces of desired lengths so as to make handling easier.

Before activating the vibrating device the elongated body may be driven into the floor under the influence of gravita forces. This may be done to preserve the sample as the vibration or impact from the device may partly damage the sample. Since the amplitude and the frequency of the impact or vibration influences the preservation of the sample, the frequency and/or amplitude of the vibrations or impact generated may be varied in response to the characteristics of the layers of floor material being penetrated by the elongated body. By varying the frequency and amplitude the distortion of the sample may thus be minimised, which may be achieved by using the lowest possible amplitude and/or frequency at any time.

The method may comprise the step of changing the amplitude and/or frequency during operation of the device, but may also include pausing the device followed by the step of changing parameters influencing the amplitude and/or the frequency and continuing the operation of the device.

The device may be moved along the elongated body for maintaining the generating device spaced above the floor surface but may also be moved continuously so as to maintain it in a substantially constant, predetermined distance above the floor surface.

The moving speed of the device may be changed e. g. continuously in response to the characteristics of the layers of the floor material being penetrated by the elongated body so as to maintain the vibrations of the generating device at a substantially constant, predetermined frequency. Thus the moving speed may be raised when the elongated body is penetrating soft layers where the frictional resistance between the elongated body and the layer is low. Analogously the moving speed may be raised when the elongated body is penetrating hard layers where the frictional resistance between the elongated body and the layer is high.

Prior to activating the vibration generating means of the device, the device may be moved upwardly into engagement with a frame structure so as to apply an additional downwardly directed force to the elongated body. By using the weight of the frame structure to drive the elongated body into the floor, the elongated body can be driven further into the floor before the generating means are activated, whereby the sample is preserved as much as possible.

Prior to the step of moving the device upwardly into engagement with the frame structure, the elongated body may be driven into the floor under influence of gravital forces applied only from the elongated body and the device.

Using the weight of the frame structure to drive the elongated body into the floor may imply that the frame structure is elevated from the floor, whereby a risk of braking the elongated body occur. Therefore the force applied from the device to the frame structure may be determined e. g. continuously during operation, so as to ensure that the frame structure is not spaced above the floor during operation of the device. The method may comprise a maximum limit for the force applied from the device to the frame structure so as to ensure that the frame structure is not spaced above the floor. If the device is moved by wheels pressed into frictional engagement with the elongated body the limit may be determined as a maximum torque which can be applied to the wheels and/or a maximum engagement force applied to the wheels, said engagement force may have a direction substantially parallel to a radial direction of the elongated body.

The distance between the device and the floor may be determined e. g. continuously during operation of the device, so as to enable positioning of the device in relation to the floor.

Furthermore the length of the part of the elongated body penetrating the floor may be determined e. g. continuously during operation of the device, whereby the elongated body may be driven into the floor using known information about the material of different layers of the floor.

As vibrations may damage parts of the sample of the floor the vibrations applied to the elongated body may be arranged so that the amplitude of said vibrations is as low as possible. Therefore the amplitude of the vibrations may initially be applied with a first amplitude and a first frequency. The frequency may be raised during operation of the device so as to minimise the impact applied to the elongated body and thereby preserving the sample taking from the floor as much as possible.

Subsequent to generating vibrations or impact with the first amplitude and the first frequency the device may generate a vibration or impact with a second amplitude and a second frequency. The second amplitude may be larger than the first amplitude, but may also be smaller if the material being penetrated has a lower friction against the elongated body. The device may shift between different amplitudes in response to the characteristics of the material of the floor being penetrated.

The frequency of the vibrations generated from the generating device, e. g. a first and second frequency, may be between 0 Hz and 250 Hz. The first frequency may be between 70 Hz and 250 Hz and the second frequency may be between 0 Hz and 70 Hz. In an embodiment the vibrations applied with a low frequency may be applied with a high amplitude and vice versa.

Depending on the amplitude of the vibrations being applied, the device may be pressed into engagement with the frame structure during vibration, so as to apply additional force to the elongated body. This may be done during vibration with a low amplitude and be followed by vibrations with a higher amplitude but where the device is not pressed into engagement with the frame structure.

The device may be controlled so that the device is spaced above the floor surface with a substantially predetermined distance. In this case the amplitude and/or the frequency may be changed during operation of the device so as to maintain the desired distance between the device and the floor. Alternatively the speed of the device may be changed resulting in altering distances between the device and the floor surface so as to maintain a predetermined frequency and/or amplitude of the vibrations generated. In this case the device moves up and down in relation the frame structure in response to the material being penetrated in the floor.

A second aspect of the invention provides an apparatus for driving an elongated body into a floor under a body of water, said apparatus comprising

an impact or vibration generating device adapted to be arranged displaceable on the elongated body for applying impacts and/or vibrations thereto so as to drive the elongated body into the floor, moving means for displacing the generating device along the length of the elongated body, and control means for controlling the moving means so as to maintain the generating device spaced above the floor surface, when the elongated body is driven into the floor.

The impact or vibration generating device may comprise hydraulic cylinders adapted to apply e. g. a downwardly directed force or may comprise a movable weight elevated and then released so as to apply a downwardly directed force. The impact or vibration generation device may also comprise an element which when rotated generates a vibration e. g. by having a eccentric distributed mass.

The moving means may be a worm motor having a first and a second set of gripping means displaceable in relation to each other, but may also comprise gripping means which when rotated moves the device along the elongated body. The moving means may be automatically or semi automatically controlled by control means so as to position the device at a desired position in relation to the floor, the frame structure or the elongated body.

The elongated body may be a tubular body such as a cylindrical or a circular cylindrical body. The elongated body may be adapted to take samples of the floor, the elongated body further comprising a separate lining tube for preserving a sample accumulated when the floor is penetrated. The lining tube may be removable from the elongated body so as to preserve the sample taken from the floor. The lining tube may be made of a transparent material so that the different layers of the sample may be visual while the sample is kept in the lining tube. The material of the lining tube and or the elongated body may made of metal and/or plastic and/or composite material, such as material comprising at least one metal and/or at least one alloy such as iron, steel, brass, gold, silver, zinc, aluminium, magnesium, titanium, copper, nickel, lead and/or platinum.

The outer surface of the lining tube may comprise indications of the length of the sample kept inside the tube. Additionally the lining tube may comprise cavities so as to ease breaking the lining into shorter parts.

The lining tube and/or the elongated body may at a first end comprise a one-way valve allowing material to move only inward at said first end of the elongated body and/or lining

tube. Said one-way valve may comprise spring leafs. The elongated body and/or the lining tube may in a second end comprise a substantially airtight one-way valve allowing material to move only outwards from said second end of the elongated body and/or lining tube. The material being moved through said valve may be water kept in the part of the elongated body or lining tube not comprising at least a part of the sample. The one-way valve could be a plate in the lining tube and/or the elongated body having at least one hole for passage of the material. A ball may be placed on top of said hole so as to block the hole when material starts to move inward.

The apparatus may further comprise a frame structure for supporting the generating device. Said frame structure may at least partly be shaped as a space truss but could also be shaped as a series of guide rods on which the device can move, the guide rods in a first end being attached to a bottom plate and in a second end being attached to a top plate.

In an embodiment the generating device may be arranged displaceable in relation to the frame structure, so as to allow the generating device to move in relation to the floor while the frame structure is placed on the floor. Furthermore the frame structure and the generating device may further comprise interacting engaging means, so as to apply an additional downwardly directed force to the elongated body when the device is engaged with said frame structure. The engaging means may be made of an elastic material such as rubber, so that the force applied when the device is moved into engagement with the frame structure is applied continuously and not momentary.

The apparatus may further comprise means for determining a gravita force transferred from the frame structure to the generating device, during operation of the device. Said means may be integrated in the engaging means but could also be attached to other parts of the frame structure and/or the device. The means for determining the force transferred from the frame structure to the generating device may be a hydraulic cylinder comprising means for determining the pressure in the cylinder when a force is applied to the piston of the cylinder. The means for determining the gravita force may also be a piezo electric element comprising means for measuring the voltage and/or current generated when a force is applied to the piezo electric element.

If the device comprises gripping means which when rotated moves the device along the elongated body, the force applied to the frame structure from the device may be determined as a resistance against rotation of said rotating gripping means.

In an embodiment the apparatus may comprise means for controlling the frequency and/or amplitude of the vibrations in response to the resistance against penetration of the

elongated body into the floor. Said means may comprise a pneumatic system and/or a hydraulic system and/or an electric system e. g. comprising a microprocessor. The means for controlling the frequency may comprise means for determining the speed of rotation of e. g. an rotating body having an eccentric distributed mass, so as to determine the frequency of the vibrations applied to the elongated body. The means for controlling the amplitude of the vibrations may comprise means for determining the centrifugal force of e. g. a rotating body having an eccentric distributed mass, but could also be means for determining a force applied to an axis to which the rotating body is attached. Alternatively the force could be determined as a function of the energy applied to keep a desired speed of the rotating body.

The apparatus may comprise movement control means adapted to control the moving means so as to maintain the generating device in a substantially constant, predetermined distance above the floor surface. This may be done by changing the frequency and/or the amplitude of the vibrating device but could also be done by changing the moving speed of the device.

The movement control means of the apparatus may be adapted to control the moving means so as to move the generating device continuously along the elongated body while maintaining a substantially constant predetermined vibration frequency. When maintaining a substantially constant predetermined vibration frequency the device may move upwards and downwards in relation to the frame structure in response to the floor material being penetrated.

The apparatus may comprise means for determining the distance between the generating device and the floor surface. Said means may be ultrasonic distance determining means, but could also be distance determining means comprising laser technology. Furthermore the distance determining means may comprise a hydraulic cylinder connected in a first end to the frame structure and in a second end to the device, the hydraulic cylinder including a piston and means for determining the position of the piston in relation to the hydraulic cylinder. The position determining means may be a movable electrically conducting resistance comprised in the hydraulic cylinder and/or the piston of the cylinder. The resistance may be arranged so that the resistance between two conductors changes when the piston is moved.

In an embodiment of the invention the apparatus further comprises means for determining the length of the part of the elongated body penetrating the floor. Said means may be ultrasonic measuring means but could also comprise a wheel connected to a revolution counter, the wheel being pressed into frictional engagement with an outer surface of the

elongated body. Said revolution counter may be a pulse indicator but could also be an electrical generator. The wheel and the revolution counter may each comprise magnetic elements, arranged oppositely so as to transfer rotations from the wheel to the revolution counter. The advantage of the latter embodiment is that gaskets between an axis transferring the rotation from the wheel pressed into engagement with the elongated body and the revolution counter may be eliminated. Said elimination of gaskets is desirable when the apparatus is operating under high pressures, such as above 200 bar or 500 bar as the pressure needed to ensure a waterproof gasket may be so high that it implies a high frictional resistance. The wheel and/or the revolution counter may each be connected to a wheel comprising magnetic elements arranged oppositely so as to transfer rotations from the wheel to the revolution counter. The magnetic wheels may comprise a base part and a series of magnets, said base part may be made of any non magnetic material such as alloys of bronze.

The generating device may comprise at least one rotatable vibrating body being a solid of revolution having an eccentric distributed mass, which may be placed inside a chamber comprising a fluid such as an oil. The outer surface of the solid of revolution may have a smooth surface with a low frictional resistance against the oil so as to reduce the pumping effect when the solid is rotated. The generating device may comprise at least one set of rotating bodies each set comprising at least two rotating bodies arranged e. g. on each side of the elongated body. Each set of rotating bodies may be controlled so that one is rotating clockwise and the other is rotating counter-clockwise e. g. so that a downwardly directed force is applied from both bodies to the elongated body as close to the elongated body as possible.

Furthermore the generating device may comprise two sets of vibrating bodies, the sets having different distributed masses, so as to allow vibrations with different amplitudes.

Each vibrating body may have at least two mass elements being movable in relation to each other, said mass element being a solid of revolution having an eccentric distributed mass. Said two movable mass elements may be two solids of resolution having distributed masses, rotatable in relation to each other so as to change the amplitude of the generating device, e. g. during operation of the device. The vibrating bodies having distributed masses may include wheels comprising chambers with fluids having different masses, said chambers being connected to e. g. a hydraulic system so as to change the masses of the chambers during operation of the apparatus.

The generating device may be adapted to generate frequencies between 0 and 250 Hz, such as between 0 Hz and 70 Hz or between 70Hz and 250Hz.

In an embodiment the moving means may comprise at least two oppositely arranged rotating cylinders having cavities on the circumference for receiving the elongated body.

The moving means may comprise at least two sets of rotating cylinders placed above each other so as to fix the device in relation to the elongated body at two sets of points.

Each set of rotating cylinders may be connected to each other so as to ensure that the cylinders rotate synchronised in opposite direction i. e. clockwise and counter-clockwise.

Said synchronisation may comprise toothed wheels or a belt drive.

The moving means may comprise means for pressing the rotating cylinders into frictional engagement with the elongated body. Said pressing means may comprise hydraulic cylinders, including means for determining the pressure applied from the rotating cylinders to the elongated body.

Brief description of the drawings Below the invention is described in further detail with reference to the drawings, wherein figs. 1 and 2 shows an apparatus according to the invention, fig. 3 shows a generating device according to the invention, fig. 4 and 5 shows a moving device according to the invention and fig. 6 shows a penetration determining means according to the invention.

Detailed description of the figures Figure 1 and 2 shows an apparatus 101 for driving an elongated body 102 into a floor under a body of water. The apparatus 101 comprises a generating device 103 attached to a frame structure 104. The generating device 103 is arranged on a plurality of gliding rods 105 so that the generating device 103 can move in relation to the frame structure 104. On the gliding rods 105 is placed interacting top engaging means 106 so as to apply an additional downwardly directed force to the elongated body 102. Interacting engaging bottom means 107 are also placed in the bottom of the frame structure 104. The generating device 103 further comprises a first set of vibrating bodies 108 capable of generating a first amplitude and a second set of vibrating bodies 109 capable of generating a second amplitude. Moving means 110 are comprised in the generating device 103, which also comprises penetration determining means 112. The moving means 110 comprises at least one set of oppositely arranged rotating cylinders 111 which are pressed into frictional engagement with the elongated body 102 by pressuring means 116. The frame structure 104 further comprises a bottom plate 113, may comprise a top plate 114 and distance determining means 115.

In figure 3 is shows a generating device 103 according to the invention. In the figure is shown a first set of vibrating bodies 108, which may each comprise a first element 117 having a first distributed mass and a second element 118 having a second distributed mass. The first element 117 and the second element 118 may be rotatable in rotation to each other so as to change the amplitude generated when the axle 119 is rotated by the motor 120 to which the axle is conned via the coupling 121.

The moving means 110 comprises a plurality of oppositely arranged rotating cylinders 111.

One of the rotating cylinders 111 are shown in figure 4. Each rotating cylinder 111 has cavities 122 on the circumference for receiving the elongated body 103. As shown in figure 5 the rotating cylinders 111 may be connected to each other via a first toothed wheel 123 so as to ensure synchronised rotation of the cylinders 111. One of the first toothed wheels 123 may be connected to a motor 124 via a second toothed wheel 125.

In figure 6 is shown the penetration detecting means 112 comprising a wheel 126 which can be pressed into frictional engagement with the elongated body 103. The wheel 126 has cavities 127 on the circumference for receiving the elongated body 103. The wheel is connected to a revolution counter 128 via magnetic wheels 129, comprising a plurality of magnets 133 so as to transfer rotation from the wheel 126 to the revolution counter 128 without a physical connection, thus the revolutions counter 128 can be encapsulated in a box 131. Conductors 132 are connected to the revolution counter 128.