Downhole Motor Stator Cold Spray Metallic Overlay
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Solution Overview
Problem
The manufacturing of stators for Positive Displacement Motors (PDMs) and Progressive Cavity Pumps (PCPs) is complex and costly due to the need for precise contour formation, and traditional connectors are challenging to integrate due to the nutating motion of the rotor, which can cause strain and limit the ease of electrical connections.
Innovation Solution
The use of cold spray technology to deposit a metallic overlay onto the interior of the stator housing to form lobes, allowing for a more efficient and cost-effective manufacturing process, and embedding conductive cables or cooling channels within the overlay to facilitate electrical connections and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional adhesive bonding and molding methods are used to form the stator, then the elastomer can be bonded to the metal housing, but the manufacturing process is complex and time-consuming due to surface preparation, adhesive application, and molding steps
Solution Approach 1:
The patent replaces the mechanical adhesive bonding process with a friction weld that creates a direct metal-to-metal bond between the stator housing and the drive shaft. This eliminates the need for adhesive application, surface preparation, and curing steps, significantly simplifying the manufacturing process while maintaining structural integrity.
Solution Approach 2:
The invention changes the bonding mechanism from chemical adhesion to mechanical friction welding. By applying rotational motion and axial force during assembly, the friction weld creates a strong metallurgical bond that eliminates the need for complex adhesive systems and reduces manufacturing steps.
2Object-affected harmful factors
If the elastomer wall thickness is reduced to minimize hysteretic heating, then the heat generation is reduced, but the sealing performance deteriorates under high pressures and loads
Solution Approach 1:
The patent employs a composite structure where a thin elastomer liner is bonded to a rigid metal stator housing. The metal housing provides structural support and maintains sealing integrity under high pressure, while the thin elastomer layer minimizes hysteretic heating. This composite approach allows the elastomer to be thinner without compromising sealing performance.
Solution Approach 2:
The stator is divided into two functional components: a thin elastomer liner that contacts the rotor and minimizes heat generation, and a rigid metal housing that provides structural support and sealing. This segmentation allows each component to be optimized for its specific function without compromise.
3Ease of operation
If traditional connectors and wiring are used in the stator, then electrical connections can be made, but the nutating motion of the rotor induces strain on the connectors limiting reliability
Solution Approach 1:
The patent integrates the electrical connection components directly into the friction-welded metal housing structure. By combining the housing, drive shaft, and electrical connection elements into a rigid integrated assembly, the design eliminates flexible connectors that would be subjected to strain from rotor nutation, thereby improving reliability.
4Manufacturing precision
If electrochemical etching, EDM, or welded indexed plates are used to form the evenwall stator contour, then the stator can achieve uniform wall thickness, but these methods are time-consuming and expensive
Solution Approach 1:
The patent replaces complex mechanical machining processes (electrochemical etching, EDM, welded indexed plates) with a friction welding process that forms the stator structure through controlled deformation and bonding. This mechanical approach achieves the required precision more efficiently and at lower cost.
Solution Approach 2:
The invention changes the manufacturing approach from subtractive or assembly-based methods to a friction welding process that forms the stator structure through controlled plastic deformation and metallurgical bonding. This parameter change enables faster production while maintaining dimensional accuracy.
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
This method simplifies the manufacturing process, enhances the reliability of the stator by reducing hysteretic heating and allowing for easier integration of electrical connections, thereby improving the overall performance and durability of the motor or pump.
Implementation Method 1
a metallic overlay deposited by cold spray onto an interior of the housing to form overlay lobes
Implementation Method 2
The cyclic compression of the elastomer can result in damage due to internal hysteresis heating
Data Source
AI summary
A downhole motor or pump assembly that includes a stator and a rotor rotatable within the stator. The stator includes a tubular housing and an overlay deposited by cold spray onto an interior of the housing to form overlay lobes along a first length of the stator. The downhole motor or pump may be used to perform downhole operations.