Process Fluid Lubricated Pump With Non-Contact Shaft Support

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Solution Overview

Problem

Conventional process fluid lubricated pumps for subsea applications are complex, costly, and prone to maintenance issues due to the need for multiple radial bearings, which complicates their design and increases the risk of failure, especially when operating in deep-sea environments with high pressure requirements.

Innovation Solution

A process fluid lubricated pump design featuring a common housing with a reduced number of radial bearings, utilizing hydrostatic support devices like throttle bushes to center the pump shaft and eliminate the need for mechanical seals, thereby simplifying the design and reducing complexity and costs while maintaining reliability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple radial bearings are used in conventional process fluid lubricated pumps, then the pump shaft is well supported, but the device complexity and cost increase

Engineering Contradiction:

Improvepump shaft support stabilityVSAvoidnumber of radial bearings

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes one or more radial bearings from the conventional pump design, extracting the unnecessary components while retaining adequate pump shaft support through the remaining bearing(s) and hydrostatic support devices

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The pump shaft is supported in a non-contacting manner using hydrostatic support devices (throttle bushes) that utilize process fluid pressure to maintain the shaft in a centered position, eliminating the need for mechanical contact bearings

Inventive Principle:

Principle #25Self-service

2Reliability

If mechanical seals are used to seal the pump shaft, then sealing is achieved, but the device complexity and maintenance needs increase

Engineering Contradiction:

Improvesealing effectivenessVSAvoidpresence of mechanical seals

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent completely removes mechanical seals from the design by using a seal-less configuration where the pump shaft rotates without mechanical contact or sealing components, relying instead on hydrostatic support to maintain shaft position and prevent leakage

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical sealing system is replaced with a hydrostatic support system that uses fluid pressure to center the shaft and maintain the necessary clearance, eliminating mechanical contact and sealing requirements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the pump design is simplified with fewer bearings, then the cost and complexity are reduced, but the rotordynamic performance may be affected

Engineering Contradiction:

Improvenumber of radial bearingsVSAvoidrotordynamic performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent uses hydrostatic support devices (throttle bushes) that utilize process fluid pressure to provide non-contact support for the pump shaft, maintaining proper shaft positioning and rotordynamic performance without mechanical bearings

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the support mechanism from mechanical contact to hydrostatic floating, using process fluid pressure as a parameter to maintain the shaft in a centered position with optimal clearance, ensuring stable rotordynamic behavior

Inventive Principle:

Principle #35Parameter changes

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 reduced complexity and cost of the pump design enhance its reliability and operational efficiency, allowing for effective subsea operation with reduced maintenance needs and improved rotordynamic performance, even in high-pressure subsea environments.

Implementation Method 1

a balance drum (7) fixedly connected to the pump shaft (5) between the pump unit (3) and the drive end (51) of the pump shaft (5), the balance drum (7) defining a drum front side (71) facing the pump unit (3) and a drum back side (72)

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

a relief passage (73) provided between the balance drum (7) and a first stationary part (26) configured to be stationary with respect to the common housing (2), the relief passage (73) extending from the drum front side (71) to the drum back side (72)

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 3

wherein the pump shaft (5) is radially supported in a non-contacting manner during operation of the pump (1)

Methodology Applied

Scientific EffectHydrostatic support:

Data Source

PatentUS11846297B2Process fluid lubricated pump

Publication Date: 2023.12.19 SULZER MANAGEMENT AG

AI summary

A process fluid lubricated pump includes a pump having a pump shaft extending from a drive end to a non-drive end, first and last stage impellers, a drive unit exerting torque on the drive end to rotate the pump shaft, a balance drum connected to the pump shaft between the pump and the drive end, the balance drum defining a drum front side facing the pump and a drum back side, a relief passage between the balance drum and a first stationary part configured to be stationary with respect to a housing, the relief passage extending from the drum front side to the drum back side, the pump shaft radially supported in a non-contacting manner during operation of the pump, and a hydrodynamic radial pump bearing supporting the pump shaft, the radial pump bearing arranged at the non-drive end or at the drive end of the pump shaft.