Progressing Cavity Pump Stator Groove Mechanical Lock
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing downhole progressing cavity pumps and motors face challenges in maintaining reliable operation at high temperatures and pressures due to adhesive failure between the polymeric sleeve and the stator tube, and are prone to sleeve 'peeling' under high forces and fluid/solid flow conditions.
Innovation Solution
The use of a rigid stator housing with circumferentially spaced, axially extending grooves and intersecting grooves on its interior surface to securely engage the polymeric sleeve, combined with seal glands to prevent axial and rotational movement, enhances the mechanical locking and bonding between the polymeric layer and the stator housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive bonding is used to bond the polymeric sleeve to the stator tube, then the assembly can be manufactured with simple bonding processes, but the bond strength fails under high temperature and pressure conditions
Solution Approach 1:
The bonding interface is segmented into multiple circumferentially spaced grooves that extend axially through the stator tube wall. These grooves create discrete bonding zones rather than a continuous bond, allowing the polymeric sleeve to be mechanically interlocked with the stator tube while maintaining manufacturing simplicity. The segmented structure prevents complete bond failure under high temperature and pressure conditions.
Solution Approach 2:
The polymeric sleeve is nested within the grooves of the stator tube, with the grooves extending into the polymeric material. This nesting creates a mechanical interlock where the polymeric sleeve is physically captured within the groove structure, providing reliable retention under high temperature and pressure without requiring complex bonding processes.
2Stability of the object's composition
If large axial grooves are used to prevent sleeve rotation, then rotational stability is improved, but the grooves occupy excessive space relative to the stator tube
Solution Approach 1:
The grooves are positioned at specific locations on the stator tube interior surface, distributed circumferentially but concentrated where needed for rotational stability. The grooves extend axially to engage the polymeric sleeve material, providing localized mechanical interlocking that prevents rotation without requiring large groove dimensions throughout the entire stator tube. This local quality approach maintains stability while minimizing space occupation.
3Reliability
If a flange is molded on the end of the polymeric sleeve to retain it on the tube, then the sleeve retention is improved, but the device complexity increases
Solution Approach 1:
Instead of adding a flange to the polymeric sleeve to retain it on the stator tube, the invention inverts the approach by creating grooves in the stator tube that capture and retain the polymeric sleeve. This inversion eliminates the need for complex flange molding operations while achieving reliable sleeve retention through the groove structure that extends into the polymeric material.
Data Source
AI summary
A progressing cavity pump/motor (10) includes a stator housing (12), a polymeric layer (14), and a rotor (16). A plurality of axially extending grooves (24) are formed in the interior surface of the stator housing for receiving polymeric material therein. At least one seal gland (46) adjacent an end of the polymeric layer maintains sealing between the stator housing and the polymeric layer.