Multi-Slip Pipe Gripping Assembly with Variable Taper Angles
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Solution Overview
Problem
Conventional slip assemblies often damage heavy weight pipes and tubular goods during installation and retrieval due to excessive radial gripping forces, and struggle to engage effectively at lower load conditions.
Innovation Solution
A slip assembly with a combination of central and supplementary slip members, where the supplementary members engage at a more vertical angle to provide sufficient radial force without crushing, and then transition to a less aggressive angle to minimize crushing effects as the load increases, using a bias spring for automatic adjustment and insert dies with teeth-like projections for secure gripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional slip assemblies use a single tapered slip member design, then they can engage at lower load conditions, but they cause excessive radial gripping forces that damage heavy weight pipes
Solution Approach 1:
The slip assembly is divided into two functional segments: supplementary slip members for light load conditions and central slip members for heavy load conditions. Each segment has optimized geometry for its specific operating range, preventing damage at light loads while maintaining gripping effectiveness at heavy loads.
Solution Approach 2:
The slip assembly transitions dynamically from supplementary to central slip members as the load increases. This automatic transition occurs through the mechanical interaction of the slip members with the pipe surface, allowing the system to adapt its gripping characteristics to match the loading conditions.
2Force
If slip members use a more aggressive taper angle to grip effectively, then gripping force increases, but crushing and damage to the pipe increases
Solution Approach 1:
Different regions of the slip assembly have different taper angles optimized for their specific functions. The supplementary slip members have a more aggressive taper angle for effective engagement at light loads, while the central slip members have a less aggressive taper angle to minimize crushing at heavy loads.
3Device complexity
If a single slip member design is used for all load conditions, then device complexity is reduced, but performance across varying loads deteriorates
Solution Approach 1:
The slip assembly achieves multi-functionality by incorporating both supplementary and central slip members in a single device. This universal design allows the same slip assembly to effectively handle a wide range of loads and pipe weights without requiring multiple separate devices or frequent reconfiguration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The slip assembly effectively grips heavy weight pipes without causing damage, maintaining a secure hold across varying loads and accommodating multiple pipe diameters without significant equipment changes, reducing the risk of human error and ensuring consistent contact for uniform load distribution.
Implementation Method 1
Each of the supplementary slip members has a substantially wedge-shaped or tapered contour profile... The outer surface of each supplementary slip member is slidably disposed on an inner surface of a corresponding central slip member... said supplementary slip members will first engage against said pipe or tubular
Implementation Method 2
using a bias spring for automatic adjustment
Implementation Method 3
insert dies with teeth-like projections for secure gripping
Data Source
AI summary
A slip assembly for gripping against the external surface of a section of pipe or other tubular goods and supporting axial loading has multiple sets of cooperating wedge-like slip members movably mounted within a slip bowl. A first set of slip members having a smaller taper angle (that is, having a greater vertical component) exerts a predetermined and limited radial gripping force on the pipe or other tubular good. Thereafter, a second set of slip members having a larger taper angle (that is, having a lesser vertical component) takes over and exerts additional radial gripping force on the pipe or other tubular good.