Bayonet Suction Cover for Reciprocating Pumps
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Solution Overview
Problem
Reciprocating pumps in oilfield operations face issues with thread fatigue in suction cover nuts due to high cyclical loads, leading to leaks and costly maintenance, as the threaded connections can 'cone out' or peel off, and become dirty, hastening failure.
Innovation Solution
A suction cover design with a plug and key system that interlocks within the access port of the fluid cylinder, eliminating the need for threaded connections, allowing for rotation between unlocked and locked positions to prevent backing out and utilizing a locking cuff to secure the plug in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded connections (suction cover nuts) are used to secure the suction cover, then the suction cover can be held in place, but the threads fatigue and fail due to high cyclical loads
Solution Approach 1:
The patent removes the threaded connection component (suction cover nut) from the system and replaces it with a bayonet-style plug that inserts directly into the access port. This extraction of the problematic threaded interface eliminates thread fatigue and failure while maintaining the securing function through a different mechanical engagement mechanism involving keys and keyways.
Solution Approach 2:
The patent substitutes the threaded mechanical connection system with a bayonet insertion system featuring keys, keyways, and a locking groove. This replacement mechanical system avoids the cyclic loading issues that cause thread fatigue by using a different engagement geometry that distributes stresses more effectively.
2Ease of manufacture
If threaded connections are used, then the suction cover can be installed, but maintenance costs increase due to thread failure and cleaning requirements
Solution Approach 1:
The bayonet-style plug is designed as a simpler, more durable component that eliminates the need for expensive thread repairs or replacement of the entire suction cover assembly. The plug can be easily removed and reinstalled without specialized tools or cleaning operations, reducing both maintenance time and costs.
Solution Approach 2:
The plug design includes self-aligning keys and keyways that guide proper insertion, and a locking groove that automatically engages to secure the connection. This self-service mechanism eliminates the need for precise thread alignment or specialized installation procedures, making maintenance simpler and faster.
3Reliability
If threaded connections are used, then the suction cover can be secured, but leakage occurs when threads fail
Solution Approach 1:
By removing the threaded connection that is prone to failure and leakage, the patent eliminates the source of the harmful leakage effect. The bayonet-style plug provides a more reliable sealing interface that maintains connection integrity under cyclic loading conditions.
Solution Approach 2:
The locking groove and keyway design provides a pre-engineered failure mode that prevents leakage before it occurs. The interlocking keys and locking groove create a mechanically superior connection that resists the cyclic loads that would otherwise cause thread failure and subsequent leakage.
Data Source
AI summary
A suction cover for a reciprocating pump assembly includes a plug configured to be at least partially received within an access port of a fluid cylinder of the reciprocating pump assembly. The plug includes at least one key configured to be received through a keyhole of the access port such that the at least one key extends within a keyway of the access port when the plug is at least partially received within the access port. The plug is configured to be rotated within the access port between an unlocked position wherein the at least one key is aligned with the keyhole and a locked position that prevents the plug from backing out of the access port.