Pressure Exchange End Cover Port for Rotor Stall Prevention

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Solution Overview

Problem

Rotating fluid handling equipment, such as pumps, are susceptible to stall conditions when handling particle-laden fluid flows, leading to undesirable speed fluctuations and downtime, especially in applications where continuous operation is critical.

Innovation Solution

The implementation of an isobaric pressure exchanger (IPX) with end covers featuring ports or openings to improve duct pressure transfer, which helps counteract forces hindering rotor rotation and promote continuous operation by facilitating pressurization and depressurization within the rotor duct, thereby enhancing the efficiency and reliability of fluid pressure transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rotating fluid handling equipment is used to handle particle-laden fluid flows, then fluid transport function is achieved, but rotor stall conditions occur due to solid particulate entering spaces between rotor and stator

Engineering Contradiction:
Improvecontinuous operation reliabilityVSAvoidparticle intrusion into rotor-stator spaces
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The pressure exchanger is divided into multiple cells arranged in series, with each cell containing a rotor and stator assembly. This segmentation allows particle-laden fluid to pass through multiple stages without accumulating in any single rotor-stator space, reducing stall risk while maintaining continuous operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A port or opening is provided in communication with the duct volume to act as an intermediary pressure equalization pathway. This allows pressure to be equalized between the duct volume and the cell during rotation, preventing pressure differentials that would cause particle intrusion and rotor stall

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If pressure equalization is achieved in pressure exchanger cells, then continuous rotation is maintained, but complex port placement is required in rotating components

Engineering Contradiction:
Improvecontinuous rotation stabilityVSAvoidrotating component structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The port is integrated into the end cover structure rather than being a separate component in the rotating assembly. This merging of functions allows pressure equalization to occur through the end cover itself, simplifying the rotating components while maintaining reliable continuous operation

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The port automatically performs pressure equalization based on the rotational position of the cells without requiring external control mechanisms. As cells rotate into and out of alignment with the port, pressure self-regulates, maintaining continuous rotation through passive pressure balancing

Inventive Principle:
Principle #25Self-service

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 solution effectively reduces the likelihood of rotor stall conditions, increases the lifespan of equipment, and minimizes downtime by maintaining consistent operation even with abrasive and corrosive fluids, allowing for the use of less expensive equipment in fracturing systems.

Implementation Method 1

A port or opening is provided in an end cover adjacent to a rotor duct opening in each cell. The port or opening enables pressurization of a rotor duct volume as the rotor duct volume rotates into alignment with the port or opening and enables depressurization of the rotor duct volume as the rotor duct volume rotates out of alignment with the port or opening.

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentEP3177837B1System and method for improved duct pressure transfer in pressure exchange system
Publication Date: 2021.02.24 ENERGY RECOVERY INC
  • EP3177837B1 patent drawingFigure 1
  • EP3177837B1 patent drawingFigure 2
  • EP3177837B1 patent drawingFigure 3

AI summary

A rotary isobaric pressure exchanger (IPX) includes a first end cover having a first surface that interfaces with a first end face of a rotor, wherein the first end cover has at least one first fluid inlet and at least one first fluid outlet. The IPX includes a second end cover having a second surface that interfaces with a second end face of the rotor, wherein the second end cover has at least one second fluid inlet and at least one second fluid outlet. The IPX includes a port disposed through the first surface of the first end cover or through the second surface of the second end cover, wherein during rotation of the cylindrical rotor about the rotational axis the port is configured to fluidly communicate with at least one channel of the plurality of channels within the rotor.