Draw-works Selective Drum Connection for Torque and Speed

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Solution Overview

Problem

Dual draw-works systems, which offer increased speed and redundancy, face challenges with large footprint and high cost due to the need for doubled motor capacity to handle heavy loads and speed requirements, while single systems lack sufficient torque and speed capacity.

Innovation Solution

A draw-works system with selectively connectable and disconnectable drums, allowing for switching between torque mode for heavy loads and speed mode for lighter loads, utilizing a 2:1 transmission mechanism without doubling motor capacity, and enabling independent operation of drums for redundancy and line exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If dual draw-works systems are used to increase speed, then hoisting speed is improved, but footprint and cost increase significantly

Engineering Contradiction:
Improvehoisting speedVSAvoidfootprint
Core Design Contradiction:
SpeedVSArea of stationary object

Solution Approach 1:

The patent combines two draw-works systems into a single integrated unit where two drums share a common rotation means. This merging allows the system to achieve the speed benefits of dual draw-works (by rotating both drums simultaneously) while occupying the space of only one draw-works unit, thus resolving the contradiction between speed improvement and footprint reduction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single draw-works unit is designed to perform multiple functions: it can operate in dual-drum mode for high-speed hoisting, in single-drum mode for heavy-load lifting, and provide redundancy for fail-safe operation. This multi-functionality allows one unit to replace what would traditionally require two separate draw-works systems, reducing footprint while maintaining speed capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Speed

If dual draw-works systems are used to increase speed, then hoisting speed is improved, but cost increases due to doubled motor capacity

Engineering Contradiction:
Improvehoisting speedVSAvoidcost
Core Design Contradiction:
SpeedVSEase of manufacture

Solution Approach 1:

The patent merges the rotation means (motor and transmission system) into a single shared unit for both drums. Instead of requiring two complete motor-capable draw-works systems, this design uses one rotation means to drive both drums, halving the motor capacity requirement while still achieving dual-drum simultaneous operation for speed enhancement, thus resolving the cost-speed contradiction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system dynamically changes operational parameters by selectively connecting or disconnecting drums from the rotation means. When high speed is needed, both drums are connected and rotate simultaneously; when heavy load is the priority, only one drum is connected to receive full torque. This parameter flexibility allows the system to achieve speed benefits without permanently requiring doubled motor capacity, reducing overall system cost.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If single draw-works system is used to reduce footprint, then footprint is reduced, but torque and speed capacity are insufficient

Engineering Contradiction:
ImprovefootprintVSAvoidtorque capacity
Core Design Contradiction:
Area of stationary objectVSPower

Solution Approach 1:

The patent introduces dynamic connectivity between the drums and the rotation means. The connection is not fixed but can be selectively engaged or disengaged, allowing the system to adapt its torque distribution in real-time. When heavy torque is needed, the system dynamically concentrates all rotational force onto a single drum; when speed is prioritized, both drums are dynamically connected to share the rotation. This dynamic capability allows a single draw-works unit to achieve the torque capacity of traditional systems while maintaining reduced footprint.

Inventive Principle:
Principle #15Dynamics

4Force

If torque is concentrated on one drum, then heavy load capacity is improved, but speed capability is reduced

Engineering Contradiction:
ImprovetorqueVSAvoidhoisting speed
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The system uses dynamic connection control to switch between torque-concentration mode and speed-optimization mode. The connection means allow the operator to selectively engage or disengage the connection between the rotation means and each drum based on operational requirements. This dynamic reconfigurability resolves the contradiction by enabling the same physical system to deliver either maximum torque or maximum speed as needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameter of drum-rotation-means connectivity based on the desired performance characteristic. When heavy load lifting is required, the parameter is set to connect rotation means to one drum only, concentrating torque. When speed is the priority, the parameter changes to connect rotation means to both drums simultaneously, distributing rotational speed across both drums to achieve higher hoisting speed. This parameter-based control resolves the torque-speed contradiction.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3075946B1Draw-works and method for operating the same
Publication Date: 2019.05.08 NAT OILWELL VARCO NORMAY AS
  • EP3075946B1 patent drawingFigure 1
  • EP3075946B1 patent drawingFigure 2
  • EP3075946B1 patent drawingFigure 3

AI summary

There is described a draw-works (1) comprising: - a first drum (4) for storing and reeling an elongated hoisting member (10); - a second drum (8) for storing and reeling said elongated hoisting member (10); and - a rotation means (24, 28) for rotating said first drum (4) and said second drum (8); wherein - at least one of said first drum (4) and said second drum (8) is selectively connectable to and disconnectable from said rotation means (24, 28). There is also described a method for operating a draw-works (1).