Seal-less Submersible Pump with Dosing Fluid Barrier
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Solution Overview
Problem
Submersible pumps used in subsea and deep water environments face challenges with mechanical seals, which are prone to failure and require complex barrier fluid systems, making them unreliable and costly, especially when dealing with process fluids containing particles.
Innovation Solution
A seal-less submersible pump design with a common housing having two compartments, one filled with dosing fluid and the other with process fluid, where the dosing fluid is used to prevent process fluid from entering the drive unit, allowing for the use of polymer bearings and reducing the need for additional fluid supply systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical seals are used to separate process fluid and barrier fluid, then sealing performance is improved, but device complexity and maintenance needs increase
Solution Approach 1:
The patent removes the mechanical seal component entirely from the system. Instead of using a mechanical seal to separate process fluid and barrier fluid, the invention employs a seal-less design where the pump shaft passes directly through the common housing without any sealing mechanism, eliminating the complexity of barrier fluid systems while maintaining operational reliability
Solution Approach 2:
The patent introduces a dosing fluid as an intermediary substance that is injected into the common housing to prevent process fluid from entering the drive unit. This dosing fluid acts as a mediator between the process fluid and the drive unit, providing protection without requiring mechanical seals or complex barrier fluid systems
2Reliability
If mechanical seals are used to prevent process fluid leakage, then sealing reliability is improved, but maintenance intervals decrease
Solution Approach 1:
The patent extracts the mechanical seal component from the system entirely, adopting a seal-less design. This eliminates the wear and failure modes associated with mechanical seals, thereby extending maintenance intervals and improving ease of repair while maintaining sealing reliability through the dosing fluid mechanism
Solution Approach 2:
The patent uses a disposable dosing fluid that can be periodically replenished instead of maintaining complex mechanical seal systems. The dosing fluid serves as a simple, easily replaceable protective medium that prevents process fluid contamination without requiring expensive mechanical seal replacements
3Reliability
If barrier fluid systems are implemented to protect drive unit, then component protection is improved, but system cost increases
Solution Approach 1:
The patent removes the complex barrier fluid system including supply units, relief systems, and monitoring equipment. Instead, it uses a simple dosing fluid injection approach that provides component protection at significantly reduced system cost and complexity
Solution Approach 2:
The dosing fluid serves as a simple intermediary that provides protection to the drive unit components without requiring expensive barrier fluid systems. This intermediary approach maintains component protection while dramatically reducing system cost
4Device complexity
If seal-less design is used to simplify pump system, then device complexity is reduced, but risk of process fluid entering drive unit increases
Solution Approach 1:
The patent introduces dosing fluid as an intermediary substance that actively prevents process fluid from entering the drive unit in the seal-less design. This mediator provides the necessary protection against fluid contamination while maintaining the simplicity of the seal-less configuration
Solution Approach 2:
The patent applies preliminary anti-action by injecting dosing fluid in advance to prevent process fluid contamination before it can occur. This proactive approach protects the drive unit components while maintaining the simplicity of the seal-less pump design
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
This design simplifies the pump system, reduces maintenance needs, and enhances reliability by eliminating mechanical seals and the need for barrier fluids, while allowing operation with process fluids containing particles without premature bearing failure.
Implementation Method 1
The mechanical seals require the barrier fluid pressure to be higher than the process pressure. Maintaining an adequate barrier fluid overpressure requires a system which supplies and relieves barrier fluid.
Implementation Method 2
A dosing unit is provided for receiving the environmental fluid, wherein the dosing unit provides the dosing fluid from the environmental fluid, and wherein the dosing unit is configured for dosing a presettable amount of the dosing fluid into the first compartment and through the first flow passage into the second compartment.
Implementation Method 3
a hydraulic unit having at least one impeller fixedly mounted on the pump shaft for conveying the process fluid from the inlet to the outlet
Implementation Method 4
an electric motor configured for rotating the drive shaft about the axial direction
Data Source
AI summary
A submersible pump includes a housing having first and second compartments. A first flow passage is between the first and second compartments. A drive unit includes a drive shaft connected to a drive end of a pump shaft to drive rotation of the pump shaft, and an electric rotates the drive shaft about the axial direction. The electric motor is arranged inside the first compartment and a hydraulic unit is arranged inside the second compartment, The pump is a seal-less pump without a mechanical seal at the pump shaft and the drive shaft. A dosing unit receives environmental fluid, and a dosing unit provides a dosing fluid from the environmental fluid. The dosing unit is for dosing a presettable amount of the dosing fluid into the first compartment and through a first flow passage into the second compartment.