Integrated Pump Shaft Seal Assembly for Submersible Rotary Fluid Pumps
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Solution Overview
Problem
Rotary fluid pumps, especially those handling abrasive fluids and slurries, often experience premature seal failure due to inadequate pressurization, leading to costly downtime and maintenance, as existing solutions require external pressure sources that increase complexity and expense.
Innovation Solution
An integrated pressurized pump shaft seal assembly that incorporates an internal volute diffusion chamber and an optimized centrifugal oil pump impeller within the pump housing, converting kinetic energy of pumped oil into static pressure to maintain a positive seal chamber pressure above ambient, without increasing motor power or pump casing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If an integrated oil pump impeller is added to the pump shaft to pressurize the seal chamber, then the seal chamber pressure is improved, but the power consumption of the motor increases
Solution Approach 1:
The patent merges the oil pump function with the existing pump shaft by integrating an oil pump impeller that rotates on the pump shaft. This integration allows the seal chamber pressurization function to be combined with the existing pump operation, avoiding the need for separate pressurization equipment and reducing overall system complexity while maintaining the pressure improvement benefit
Solution Approach 2:
The integrated oil pump impeller serves multiple functions: it pressurizes the seal chamber to prevent fluid ingress, and the pressurized oil also serves to cool the mechanical seals and bearings. This multi-functionality reduces the need for additional separate systems, addressing the power consumption concern by consolidating functions into a single integrated component
2Stress or pressure
If the diameter of the oil pump impeller is increased to generate sufficient pressure, then the seal chamber pressure is improved, but the pump casing size must be increased
Solution Approach 1:
The patent changes the operational parameters of the oil pump impeller by optimizing its rotation speed and the viscosity of the seal oil to achieve sufficient pressurization without increasing impeller diameter. This allows the seal chamber to maintain positive pressure while keeping the pump casing size within existing constraints
3Stress or pressure
If external pressure sources are used to pressurize the seal chamber, then the seal chamber pressure is improved, but the device complexity and expense increase
Solution Approach 1:
The system uses the pump shaft's own rotation to drive the oil pump impeller, which pressurizes the seal chamber. This self-service approach eliminates the need for external pressure sources or additional power supplies, reducing system complexity and expense while achieving the desired pressurization function
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
Effectively prevents ingress of external fluids into the seal chamber, reducing seal failure and maintenance costs by maintaining a positive pressure within the seal chamber, thus enhancing the reliability and efficiency of rotary fluid pumps.
Implementation Method 1
a centrifugal oil pump impeller operable to pump the oil from the oil reservoir to the seal chamber
Implementation Method 2
an internal volute diffusion chamber and an optimized centrifugal oil pump impeller within the pump housing, converting kinetic energy of pumped oil into static pressure
Data Source
AI summary
An integrated pressurized pump shaft seal assembly for a submersible rotary fluid pump comprises an oil reservoir having a pressure equal to or less than the ambient pressure external fluids surrounding the casing, the oil reservoir feeding an oil pump impeller that is mountable onto, so as to be rotated by, the rotary fluid pump shaft. The oil pump impeller is in fluid communication with an internal volute diffusion element integrated into a pump component. The centrifugal oil pump impeller pumps oil from the oil reservoir to the seal chamber through the internal volute diffusion element so as to increase a pressure within the seal chamber to a positive pressure above the ambient pressure of the external fluids surrounding the pump housing.