Liquid Ring Pump Inter-Stage Bypass for Startup Efficiency

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Solution Overview

Problem

Liquid ring pumps face inefficiencies in startup and low-pressure operations due to the lack of a direct bypass system, leading to suboptimal performance and potential damage from compressor overload.

Innovation Solution

A modular liquid ring pump design incorporating a pressure-sensitive mechanical valve and inter-stage bypass system that allows direct discharge from the first stage to the pump discharge during startup or low-pressure conditions, and an overload protection system to prevent damage from excessive liquid accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a two-stage pump configuration is used to achieve higher pressure discharge, then the discharge pressure is improved, but the startup efficiency deteriorates due to lack of direct bypass

Engineering Contradiction:
Improvedischarge pressureVSAvoidstartup efficiency
Core Design Contradiction:
Stress or pressureVSProductivity

Solution Approach 1:

The pump system is segmented into two operational modes: a two-stage compression path for high-pressure operation and a single-stage bypass path for startup and low-pressure operation. The inter-stage bypass passage divides the flow path, allowing gas to either proceed through the second stage impeller or bypass directly to discharge, enabling optimal performance across different operating conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between operational configurations using a check valve that automatically opens or closes based on discharge pressure conditions. During startup when discharge pressure is low, the check valve opens to create a direct bypass path. During normal high-pressure operation, the check valve closes to force gas through both stages, enabling adaptive optimization of startup efficiency and discharge pressure.

Inventive Principle:
Principle #15Dynamics

2Stress or pressure

If the second stage is always in operation to maintain high discharge pressure, then the pressure performance is improved, but the system complexity and energy consumption worsen

Engineering Contradiction:
Improvedischarge pressureVSAvoidsystem complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The check valve provides automatic, pressure-driven control that dynamically reconfigures the pump system without requiring complex control mechanisms. The valve responds to discharge pressure conditions, automatically switching between two-stage and bypass modes, thereby maintaining pressure performance when needed while simplifying operation during startup without adding significant system complexity.

Inventive Principle:
Principle #15Dynamics

3Stress or pressure

If the check valve closes to force gas through the second stage, then the discharge pressure is improved, but the startup time increases

Engineering Contradiction:
Improvedischarge pressureVSAvoidstartup time
Core Design Contradiction:
Stress or pressureVSLoss of time

Solution Approach 1:

The check valve automatically adjusts the flow path based on real-time discharge pressure conditions. During startup when pressure is low, the valve remains open to provide a direct bypass path, enabling rapid pressurization and reducing startup time. Once discharge pressure reaches operational levels, the valve closes to route gas through the second stage, ensuring optimal pressure performance without prolonged startup delays.

Inventive Principle:
Principle #15Dynamics

4Power

If liquid accumulates in the working chamber during overload conditions, then the compression ratio is improved, but the reliability deteriorates due to potential damage

Engineering Contradiction:
Improvecompression ratioVSAvoidpump reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The mechanical relief valve acts as a safety intermediary between the working chamber and discharge passage. When liquid accumulation during overload conditions creates excessive pressure that threatens pump reliability, the relief valve automatically opens to release excess liquid through the bypass passage, preventing damage to the pump while allowing compression ratio optimization during normal operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical relief valve provides preemptive protection against overload damage by establishing a pressure relief path before excessive liquid accumulation can cause harm. The valve is positioned and sized to activate at predetermined pressure thresholds, cushioning the system against the harmful effects of liquid overload while maintaining optimal compression performance during normal operation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

Enhances startup efficiency, optimizes low-pressure operation, and prevents damage from compressor overloads by allowing direct bypass and automatic relief of excess liquid, improving overall pump performance and reliability.

Implementation Method 1

an inter-stage bypass system that includes an opening in an inter-stage passage and a pressure sensitive mechanical valve that allows the discharge of a first stage compressor to flow directly to the pump discharge at start up or during low pressure operation

Methodology Applied
Scientific EffectPressure-sensitive mechanical valve operation: Pressure Gradient

Data Source

PatentEP3052809B1Liquid ring pump with an inter-stage bypass
Publication Date: 2020.04.15 GARDNER DENVER NASH LLC
  • EP3052809B1 patent drawingFigure 1
  • EP3052809B1 patent drawingFigure 2
  • EP3052809B1 patent drawingFigure 3

AI summary

A modular liquid ring pump has a liquid ring overload protection system including a passage from a working chamber directly to the pump discharge passage and a mechanical relief valve configured to release liquid from the working chamber during compressor overload. The liquid ring pump, when configured to have two stages, has an inter-stage by-pass system that includes an opening in an inter-stage passage and a pressure sensitive mechanical valve that allows the discharge of a first stage compressor to flow directly to the pump discharge at start up or during low pressure operation. The liquid ring pump's modular construction may be easily configured from a single stage pump to a two-stage pump and vice versa by using the same bearings, head, and drive system and only changing the body, cone, and rotor.