Rotary Valve Reciprocating Drive for Variable Jarring Force
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Solution Overview
Problem
Existing jarring apparatuses, such as rotary jarring devices, face issues with high stress concentrations and potential failure due to reduced contact surface area at peak displacement, and mechanical systems require complex design considerations for varying force magnitudes.
Innovation Solution
A reciprocating drive apparatus with a rotary valve assembly that generates forces through relative rotation between a mandrel and housing, utilizing fluid pressure to cyclically pressurize and depressurize a piston chamber, allowing infinite variability in force frequency and magnitude, and operates irrespective of pressure differential direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rotary cams with inter-engaging ramp profiles are used to provide rotary jarring, then jarring forces can be generated in response to rotational drive input, but the contact surface area reduces significantly at peak displacement generating very high stresses that may cause cam failure
Solution Approach 1:
The patent replaces the direct mechanical cam-to-cam contact system with a fluid pressure-based system. Instead of relying on mechanical ramp profiles to generate jarring forces, the invention uses a piston chamber that is pressurized and depressurized through a rotary valve assembly, substituting mechanical stress with hydraulic pressure to achieve the same jarring effect without the associated stress concentration problems
Solution Approach 2:
The invention introduces a fluid pressure system comprising a piston chamber, piston, and rotary valve assembly. The piston chamber is cyclically pressurized and depressurized through the rotary valve, causing the piston to reciprocate and generate jarring forces. This hydraulic approach eliminates the mechanical contact stress issues inherent in cam-based systems while providing smooth, controlled force generation
2Device complexity
If linear jarring apparatus are used, then the design is simpler, but they operate only in response to linear activation input and cannot provide rotary jarring capability
Solution Approach 1:
The invention creates a multi-functional system that can accept rotational drive input and convert it to linear reciprocating motion through the piston. The same basic mechanism can potentially be adapted for linear activation as well, providing versatility while maintaining reasonable design complexity through the modular piston-chamber-valve architecture
3Length of moving object
If cam surfaces are designed to achieve peak displacement, then the desired axial displacement is achieved, but the contact surface area reduces to a point creating theoretically infinite stresses
Solution Approach 1:
The patent eliminates the problematic cam surface contact entirely by substituting it with a fluid pressure system. The piston chamber volume changes are achieved through the rotary valve controlling fluid flow, not through mechanical cam profiles, thereby avoiding point-contact stress concentrations while maintaining the ability to achieve required displacement amplitudes
Solution Approach 2:
The invention introduces fluid pressure as an intermediary between the rotational valve operation and the linear piston motion. Instead of direct mechanical contact between cam surfaces, the rotary valve modulates fluid pressure which then acts on the piston surface, distributing forces evenly and eliminating stress concentration at discrete contact points
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 apparatus provides flexible and reliable generation of jarring or impact forces with infinite variability, suitable for downhole applications, particularly in extended reach or high-angle wellbores, without the need for mechanical displacement systems and complex modifications.
Implementation Method 1
a pressure configuration in which the piston chamber is in pressure communication with the valve inlet and isolated from the valve exhaust to permit the piston to move in the first axial direction in accordance with the piston chamber being pressurised via the valve inlet
Implementation Method 2
an exhaust configuration in which the piston chamber is isolated from the valve inlet and in pressure communication with the valve exhaust to permit the piston chamber to be depressurised and the piston to move in the second axial direction
Data Source
AI summary
A reciprocating drive apparatus (10) comprises a housing (12) and a mandrel (14), wherein the mandrel (14) and the housing (12) are configurable to be rotated relative to each other. The apparatus (10) further comprises a reciprocating piston (16) mounted within a piston housing (18) to define a piston chamber (20a), wherein the piston (16) is moveable in reverse first and second axial directions (A,B), and a rotary valve assembly (24) comprising a valve inlet (28) for communicating with a pressure region (P) and a valve exhaust (30) for communicating with an exhaust region (E). The rotary valve assembly (24) is operated by relative rotation between the mandrel (14) and the housing (12) to be cyclically reconfigured between a pressure configuration and an exhaust configuration. When in the pressure configuration the piston chamber (20a) is in pressure communication with the valve inlet (28) and isolated from the valve exhaust (30) to permit the piston to move in the first axial direction (A) in accordance with the piston chamber being pressurised via the valve inlet (28). When in the exhaust configuration the piston chamber (20a) is isolated from the valve inlet (28) and in pressure communication with the valve exhaust (30) to permit the piston chamber to be depressurised and the piston (16) to move in the second axial direction (B). Movement of the piston (16) in at least one of the first and second axial directions (A,B) generates an applied force within the apparatus (10) and/or an applied force output from the apparatus (10).