Sealed Rotor Coupling With Locking Nut for Abrasive Pump Wear
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Solution Overview
Problem
Progressive cavity pumps used for viscous materials like thermal interface material face significant abrasive wear due to the high content of Aluminum Oxide, leading to frequent component replacement and increased operating costs, especially at the connection between the rotor and universal joint where abrasive material can erode the pin holes, necessitating complex disassembly and reassembly.
Innovation Solution
The design incorporates a universal joint with a locking nut and o-rings to secure the rotor to the universal joint, preventing abrasive material from entering the connection and allowing for easy assembly and replacement of either the rotor or universal joint without requiring additional connectors like pins, thereby enhancing durability and reducing maintenance costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pin connection is used to join the rotor cup to the universal joint shaft, then torque transmission is achieved, but abrasive material enters the pin holes and causes erosion leading to connection failure
Solution Approach 1:
The invention removes the pin connection entirely from the rotor-universal joint assembly. Instead of using pins that create vulnerable holes for abrasive entry, the rotor cup is directly press-fit onto the universal joint shaft, eliminating the pin holes that served as pathways for abrasive material to penetrate and erode the connection.
Solution Approach 2:
The invention introduces a press-fit interface as an intermediary connection method between the rotor cup and universal joint shaft. This direct fit acts as a mediator that transmits torque without requiring pins, thereby preventing abrasive material from entering through pin holes while maintaining reliable torque transmission.
2Strength
If the rotor and universal joint are assembled together as a single unit, then connection strength is improved, but replacement costs increase due to complex disassembly and reassembly
Solution Approach 1:
The invention segments the rotor and universal joint as separable components while maintaining a strong connection during operation. The press-fit interface allows the rotor cup to be firmly attached to the universal joint shaft during use, providing sufficient connection strength, while enabling easy separation when component replacement is needed, thus resolving the contradiction between strength and ease of repair.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A progressive cavity pump includes a sealed drive between a screw rotor (24) and an universal joint (26). The universal joint (26) includes a socket (38) configured to receive a drive shaft (40) of the rotor. To transmit torque the socket (38) and the drive shaft (40) preferably have mating square contours. A locking nut (28) is disposed over the connection between the screw rotor (24) and the universal joint (26). Seals (30) are retained in place by the locking nut (28) to prevent abrasive materials from entering into the interface between the screw rotor (24) and the universal joint (26).