Hydraulic Cam Disc Gripping Device for Drill String Handling
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Solution Overview
Problem
Existing gripping devices for drill strings are time-consuming in connection and disconnection processes, particularly when handling underwater equipment, and lack efficient mechanisms for locking and unlocking in marine environments with varying pressure conditions.
Innovation Solution
A hydraulically activated, rotatable cam disc within an annular actuator housing that moves locking slides from a retracted position to engage with the drill string, utilizing differential pressure and dynamic seals for operation in marine environments, with a hydraulic coupler for actuation and spring-loaded mechanisms for slide return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If equipment is handled by mechanical or hydraulic tools joined to the drill string, then reliable gripping and locking is achieved, but the connection and disconnection process becomes time-consuming
Solution Approach 1:
The gripping device is divided into multiple independent locking slides (at least three) that can operate independently around the drill pipe. Each locking slide can engage and disengage separately, allowing for more efficient operation compared to a single monolithic gripping mechanism. This segmentation enables parallel operation of multiple locking points.
Solution Approach 2:
The invention replaces traditional mechanical gripping mechanisms with a hydraulic actuation system. A hydraulic cylinder drives a cam mechanism that automatically moves the locking slides into engagement with the drill pipe. This hydraulic-mechanical substitution reduces the need for manual operation and speeds up the connection and disconnection process while maintaining reliable gripping.
2Reliability
If locking slides are pushed out by hydraulic pressure, then secure engagement with drill string is achieved, but returning slides to housing becomes difficult under varying pressure conditions
Solution Approach 1:
The invention uses the reverse hydraulic pressure differential to achieve slide return. When the hydraulic pressure is reduced or reversed, the pressure differential automatically pushes the locking slides back into the housing. This inversion principle allows the same hydraulic system that pushes slides out to also retrieve them, simplifying the return mechanism.
Solution Approach 2:
The locking slides are designed to return automatically to the housing without requiring separate actuation mechanisms. The hydraulic pressure differential and spring forces work together to self-return the slides after locking engagement is achieved. This self-service mechanism reduces operational complexity and improves ease of use.
3Reliability
If multiple locking slides are used around drill pipe periphery, then gripping reliability is improved, but device complexity increases
Solution Approach 1:
The hydraulic cylinder and cam mechanism serve multiple functions: they simultaneously actuate all locking slides for engagement and disengagement. This multi-functional design allows a single actuator to control multiple locking points, reducing the need for separate actuators for each slide and thereby managing complexity while maintaining reliable multi-point gripping.
Solution Approach 2:
The invention combines multiple locking slides into a single integrated gripping device that operates around the drill pipe. The locking slides are merged into a cohesive structure with shared actuation mechanisms, allowing them to function as a unified system rather than independent components. This merging reduces overall device complexity while maintaining the benefits of multi-point contact.
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
Facilitates efficient handling and locking of equipment on drill strings, reducing time-consuming operations and ensuring secure engagement and disengagement in underwater conditions, even with varying pressure differences.
Implementation Method 1
a hydraulic actuator (8B) which is arranged to move the hydraulic coupler (8A) into or out of a connection port (7C) in the actuator housing (2)
Implementation Method 2
utilizing differential pressure and dynamic seals for operation in marine environments
Implementation Method 3
spring-loaded mechanisms for slide return
Data Source
AI summary
A gripping device is adapted for handling equipment with a drill string, wherein an annular actuator housing includes a hydraulically activated, rotatable cam disc which is arranged to displace a number of locking slides from a first position, in which the locking slides are retracted into the actuator housing, and a second position, in which the locking slides are in engagement with the drill string extending through a center opening in the gripping device, by abutting against a shoulder of a tool joint in the drill string. The gripping device is connected to a hydraulic supply and return for the actuation of the cam disc via a hydraulic coupler in a connection port on the actuator housing. Alternatively pressurizing and ventilating two adjacent actuation volumes in the cam disc brings about rotation of the cam disc within a sector of the cam disc.