HK1050351B - Winch - Google Patents

Description

The invention relates to a winch, in particular a Kelly winch for underground drilling equipment, as defined in the general concept of claim 1. Such a winch comprises a rotating storage drum for the reception of a rope, a drive which turns the drum to open and unwind the rope, a device for measuring a rope load and a control unit for the drive, whereby the control unit determines a tensile force on the rope based on the measured rope load and is comparable to a specified residual pull.

A winch or rope winch is derived from DE 297 23 821. This rope winch is universally applicable and allows for a wide variety of applications to operate efficiently. In particular, a control unit is provided that measures a tensile force in connection with a measuring device and ensures that a residual tensile force is maintained on the rope. If the load on the rope rises with a far-spinning drum, the rope would no longer be under tension and a larger amount of flapping rope would then form. This no longer-tensioned rope can cause the rope windings to no longer lie in the grooves of the rope drum, as intended, but become overhangs, or the windspring to lie uncontrollably unevenly.

In the case of the generating winch, this is prevented by stopping the winds when the measured traction force falls below the minimum or residual traction force specified, which in many cases reliably prevents the formation of slack rope and the associated disadvantages.

For certain applications, especially when using the wind as a Kelly wind for the rotary drilling process, this can cause problems. For example, if the load, for example a Kelly rod, hits a fixed resistor or a more solid medium, for example water in a borehole, before reaching the desired depth, which has a higher resistance than the air of the already drilled hole, the pulling force on the rope may be less than the residual pulling force. This then leads to a shutdown of the wind drive.

For this reason, a so-called mechanical free-falling free-falling wind is often used for this use case of the drill with crankshaft, where a disc clutch releases or slows down the wind drum.

EP 0 790 356 A1 describes a control device for a floor preparation machine which includes a wind to raise and lower the floor preparation machine and a force-of-entry control device which controls the wind so that a force of entrance of the floor preparation machine reaches a predetermined level.

JP 05-321287 also includes a ground handling equipment which is held by a wind drum and which includes a control device which changes the operating mode when the load on the top of the ground handling equipment exceeds a limit value.

The EP 0 518 297 A1 reveals a drill and a method for controlling the forward speed of a drill tool of the drill.

The purpose of the invention is to improve a generic winch and to provide a method for operating a winch that enables efficient winch operation in a particularly wide range of applications.

The problem is solved by a winch with the characteristics of claim 1 and by a process for operating a winch as claimed by claim 5.

The control unit and the measuring device of the fan according to the invention are designed to continuously determine the momentary tractive force on the rope and, if the tractive force falls below the residual tractive force, the power of the drive may be reduced and adjusted by the control unit, by means of a control to keep the tractive force above the residual tractive force.

In contrast to the state of the art, when the residual tractive force is less than the minimum, the power of the drive is not stopped, but only reduced to a small value. This reduces the speed of the load, whereby the rope tension increases and can rise above the threshold of the residual tractive force. Preferably, then, the power of the drive can be increased again, so that a near-optimal speed can be regulated. A simple black-and-white control is therefore used, which completely shuts off the torque when the wind is less than the minimum.

A preferred embodiment of the crankshaft according to the invention is that the drive is designed as a hydraulic drive. Unlike an electric motor, a hydraulic drive is relatively rigid, i.e. it can perform power changes and thus speed changes of the rope according to the specifications of the control unit with a very small delay. This is particularly advantageous for quick adjustment near the optimal working point and the optimal descent speed.

The special advantage is that the control unit, together with the hydraulic drive, forms an electro-hydraulic control unit, which can control an electric valve or a very small electric actuator, which in turn controls the hydraulic drive, for example by means of a hydraulic torque booster.

For particularly simple and accurate measurements of the rope load, it is preferable to place the measuring device on a coil or in the drum area.

The control unit shall preferably have a data store for storing at least essential data from the previous lift cycle, such as lift lengths and reversal points, and a processor for evaluating and influencing the next lift cycle based on the data.

The method of the invention provides that, when the momentary tractive force falls below the residual tractive force, the control unit reduces and adjusts the power of the drive and regulates the power of the drive by the control unit on the basis of the momentarily determined tractive force.

The method of operation of a wind turbine according to the invention achieves the advantages described above.

A particularly efficient operation with respect to the descent speed is achieved by the measuring device continuously measuring the rope load and the control unit continuously determining the current tensile strength of the rope and comparing it with the specified residual tensile strength.

The invention also provides that, in order to stop the rope at a lower lifting point, a depth reversal point is stored in the control unit at each lift cycle and that, before reaching the previously stored depth reversal point, the power of the drive is reduced by the control unit at the next lift cycle. This is particularly advantageous in so-called Kellogg drilling to achieve a faster and more simultaneous stop of the rope load. First, each lift cycle is started by measuring and evaluating the rope reversal speed by a dedicated longitudinal boomerang device, at which point the respective reversal point is reversed from a downward movement to an upward movement or reversal. This reversal point is reversed accordingly in a similar or similar speed.

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The invention is further explained by a preferred example of the design shown schematically in the drawings. Figure 1 shows a side view of a rope winch of the invention and Figure 2 shows a cross-sectional view according to the section A-A of Figure 1.

Figures 1 and 2 illustrate a rope winch 10 according to the invention. A drum 12 is mounted on a rack 13 with two rack supports 13a, 13b via drum bearings 14a, 14b, rotatable around a centre axis 18 and the drum 12 is designed to accommodate a rope 11 which can be wrapped onto the drum 12 in one or several layers.

The rotary drive of drum 12 and thus the unwinding or unwinding of the wire 11 is provided by a drive 16. This can be a motor or a combination of a motor and a gear. In the embodiment shown, the drum 12 is formed as a hollow drum in which the drive 16 with its drive shaft 17 is located coaxially to the centre axis 18. The torque transmission between the drive 16 and the drum 12 is carried out by a rotary connection, which can be a wedge connection.

To determine the force applied to the rope 11, the drive 16 is stored within drum 12 via drive bearing 19 which can be rotated; to support the torque when drum 12 is rotated, the drive 16 is connected to the rack 13 by means of a lever-shaped torque support 20 only.

The torque support 20 is supported by two connecting bolts and is equipped with an unmarked measuring device to determine the torque supported. The measured value can be transmitted, for example, by a line 21 to an unmarked computer unit, where a force on the rope 11 is measured according to the diameter of the drum, taking into account the number of rope layers on the drum 12 which can increase the actual diameter of the drum.

Claims (7)

1. Winch, particularly Kelly winch for deep-well drilling tools, having

   - a drum (12), mounted in rotary manner, for receiving a cable (11),

   - a drive (16) through which the drum (12) can be rotated for winding and unwinding the cable (11),

   - a measuring device for measuring a cable load and

   - a control unit for the drive (16), said control unit, as a result of the measured cable load, being able to continuously determine an instantaneous tension on the cable (11) and to compare it with a predeterminable residual tension and if the tension drops below the residual tension the power of the drive (16) can be correspondingly reduced and adapted, the tension being kept by a control above the residual tension,

   characterized in that

   - for stopping the cable (11) at a lower lift point in each lift cycle a depth reversal point can be stored in the control unit and that prior to reaching the depth reversal point stored beforehand during the following lift cycle, the power of the drive (16) can be reduced by the control unit.
2. Winch according to claim 1, characterized in that the drive (16) is constructed as a hydraulic drive.
3. Winch according to claim 2, characterized in that, together with the hydraulic drive, the control unit forms an electrohydraulic control system.
4. Winch according to one of the claims 1 to 3, characterized in that the measuring device is located on a guide pulley or in the vicinity of the drum (12).
5. Method for operating a winch (10) according to the preamble of claim 1, in which, if the instantaneous tension drops below the residual tension, the control unit reduces and adapts the power of the drive (16), the power of the drive (16) being controlled by the control unit on the basis of the instantaneously determined tension, characterized in that for stopping the cable (11) at a lower lift point in each lift cycle a depth reversal point is stored in the control unit and that in the following lift cycle before reaching the depth reversal point stored beforehand the power of the drive (16) is reduced by the control unit.
6. Method according to claim 5, characterized in that the cable load is continuously measured by the measuring device and that the control unit continuously determines the instantaneous tension of the cable (11) and compares it with the predetermined residual tension.
7. Method according to one of the claims 5 or 6, characterized in that for stopping the cable (11) at an upper lift point prior to the reaching thereof the power of the drive (16) is reduced by the control unit.