Variable Speed Multi-Pump Friction Loss Compensation

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Solution Overview

Problem

In variable speed multi-pump booster systems, existing methods require a flow meter to determine friction loss, leading to excessive energy consumption due to varying pressure at low flow demands, as they fail to compensate for system friction loss effectively without additional hardware.

Innovation Solution

A signal processor module calculates system friction loss using speed-related signaling, allowing for adjustments to the set point to maintain constant discharge pressure without a flow meter, by determining the number of pumps running and their control areas, and interpolating between minimum and maximum set points to compensate for friction loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a flow meter is used to determine friction loss, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvefriction loss measurementVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces speed reference signaling as an intermediary parameter to indirectly determine friction loss. Instead of directly measuring flow with a flow meter, the system uses pump speed signals as a mediator to calculate friction loss through interpolation between minimum and maximum set points, thereby avoiding the need for additional measurement hardware

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical flow meter with an electronic calculation approach. The friction loss determination is substituted from a mechanical measurement device to an electronic interpolation method based on speed references and control curves, eliminating the need for physical flow sensing hardware

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If pressure is maintained constant without friction loss compensation, then discharge pressure stability is improved, but energy consumption increases

Engineering Contradiction:

Improvedischarge pressure stabilityVSAvoidenergy consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic set point adjustment based on varying friction loss conditions. The control set point is made dynamic by interpolating between minimum and maximum values based on current flow conditions, allowing the system to adapt pressure maintenance requirements to actual system demands rather than maintaining constant pressure regardless of flow conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the pressure parameter dynamically by adjusting the control set point based on calculated friction loss. The set point is varied as a function of flow conditions, transforming from a fixed parameter to a variable parameter that adapts to system demands, thereby reducing energy consumption while maintaining adequate pressure stability

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If friction loss compensation is implemented without flow meter, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:

Improvesystem complexityVSAvoidfriction loss calculation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the calculated friction loss is continuously used to adjust the control set point. The system monitors pump operation conditions, calculates friction loss based on speed references, and feeds this information back to modify the pressure control target, creating a closed-loop system that improves accuracy without additional sensors

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary calculation of friction loss characteristics by establishing minimum and maximum set points corresponding to minimum and maximum flow conditions. These pre-determined reference values are then used through interpolation to determine friction loss at intermediate conditions, allowing accurate compensation without real-time flow measurement

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3092412B1Variable speed multi-pump application for providing energy saving by calculating and compensating for friction loss using speed reference

Publication Date: 2019.11.13 FLUID HANDLING LLC

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AI summary

Apparatus features a signal processor or processing module configured to respond to signaling containing information about a set point and a speed related to one or more pumps in a pump system, e.g., including a variable speed multiple pump booster system, operating at a substantially constant discharge pressure; and determine an adjustment to the set point to compensate for system friction loss and maintain the substantially constant discharge pressure of the variable speed multiple pump booster system for flow variation, based at least partly on the signaling received. The signal processor or processing module 10a provides corresponding signaling containing information to control the one or more pumps in the variable speed multiple pump booster system.