Heated Intermediate Distance Piece for Cryogenic Pump Seal Stability
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Solution Overview
Problem
Cryogenic reciprocating pumps face issues with piston packing seal deformation and ice buildup at low operating speeds, leading to leakage and reduced seal effectiveness due to inadequate warming of the seals and ineffective wiper mechanisms.
Innovation Solution
Incorporating heating elements within the intermediate distance piece to warm the piston packing seals, combined with sealing covers and a warm, dry vapor purge to prevent ice formation and moisture intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the pump is operated at lower speeds for extended periods, then energy consumption is reduced, but ice buildup increases on the cold end piston and intermediate distance piece
Solution Approach 1:
The heating element is installed in advance within the intermediate distance piece to prevent ice buildup on the cold end piston before it occurs during low-speed operation. The heating element activates to counteract the harmful freezing effect, allowing the pump to operate at lower speeds without suffering from ice accumulation problems.
2Reliability
If heating elements are added to warm the piston packing seals, then seal deformation is reduced, but device complexity increases
Solution Approach 1:
The heating element is integrated into the intermediate distance piece, merging the warming function with an existing structural component. This combination approach adds the necessary heating capability to prevent seal deformation while minimizing the increase in overall device complexity by utilizing the intermediate distance piece as the heating housing.
3Reliability
If the intermediate distance piece is used to thermally isolate the warm end from the cold ends, then crosshead oil seal protection is improved, but piston packing seal warming is insufficient at low speeds
Solution Approach 1:
The heating element provides localized thermal energy specifically to the piston packing seal region within the intermediate distance piece. This local heating approach maintains the overall thermal isolation function of the intermediate distance piece for protecting the crosshead oil seal, while simultaneously providing the necessary warmth to the piston packing seals to prevent deformation during low-speed operation.
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 solution effectively increases the operating temperature of the piston packing seals, reducing deformation and maintaining seal integrity during continuous operation at low speeds, while preventing ice and frost formation, thus enhancing the longevity of the seals.
Implementation Method 1
heating elements to transfer heat through the cryogenic reciprocating pump cold end housing to warm the piston packing seals
Implementation Method 2
a purge connection to eliminate ambient water vapor from within the intermediate distance piece by purging the intermediate with warm, dry vapor
Implementation Method 3
These materials are suitable for service at cryogenic temperatures, but have a thermal contraction rate much greater than the cold end piston that the piston packing seals surround. The difference in thermal contraction increases the stress in the piston packing seals at low temperatures resulting in increased cold flow deformation
Data Source
AI summary
The present invention teaches providing heating elements into the nose of an intermediate distance piece of a cryogenic reciprocating pump in order to warm the piston packing seals of the pump. The heating elements increase the temperature of the piston packing seals to limit deformation of the seals while the pump is in operation. In addition, a warm, dry vapor purge may be provided to the interior of the intermediate distance piece to reduce or eliminate rime from interfering with the piston packing seals.