Circulation Pump Control for Parallel Flow Pressure Mismatch

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Solution Overview

Problem

In hydraulic circulation systems, regulating individual circulation pump units is challenging due to shared flow paths, leading to pressure loss mismatches and incorrect adjustments when multiple pump units are operational, affecting system performance and pressure supply.

Innovation Solution

A circulation pump unit with an electric drive motor and a control device that detects state variables from parallel flow paths, allowing it to adjust its control scheme to compensate for changes caused by other pump units, thereby maintaining hydraulic state stability and preventing mismatches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple circulation pump units are operated in parallel with shared flow paths, then the system can serve multiple heating circuits, but the pressure drop in the common flow path increases causing incorrect control adjustments in individual pump units

Engineering Contradiction:
Improveability to serve multiple heating circuitsVSAvoidcontrol accuracy of individual pump units
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The control unit detects the actual pressure drop across the common flow path and uses this feedback information to adjust the pump characteristic curve. This allows the pump unit to compensate for pressure losses caused by other operational pump units, maintaining accurate control despite changes in system conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The pump characteristic curve is made dynamic and adaptable. Instead of using a fixed control curve, the system automatically adjusts the characteristic curve based on detected pressure drops and system conditions, allowing the pump to optimize its performance across varying operational scenarios.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the control scheme is automatically adjusted based on detected pressure changes, then the pump can compensate for system changes, but the system becomes more complex

Engineering Contradiction:
Improveautomatic adaptation to system changesVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pump unit performs self-adjustment by detecting its own operational parameters and automatically modifying its control characteristic curve. This self-service capability eliminates the need for external manual intervention or complex centralized control systems, reducing overall system complexity while maintaining adaptability.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3369934B1Circulation pump
Publication Date: 2024.12.11 GRUNDFOS HLDG
  • EP3369934B1 patent drawingFigure 1
  • EP3369934B1 patent drawingFigure 2
  • EP3369934B1 patent drawingFigure 3

AI summary

The invention relates to a circulating pump unit (22) with an electric drive motor (10) and an electronic control unit (12) for controlling the drive motor (10), wherein the control unit (12) is configured for speed control of the drive motor (10) according to a control scheme (I, II, III), wherein the control unit (12) has a detection function (42) which is configured to detect a state variable representing an operating state from a parallel flow path (16, 18, 20) with a second circulating pump unit (22), and wherein the control unit (12) is configured such that it can modify the control scheme (I, II, III) based on a state variable detected by the detection function (42). Furthermore, the invention relates to an arrangement of at least two such circulating pump units (22) and a method for controlling two such circulating pump units (22).