Twin Circulation Pump Control for Stable Changeover Flap Position

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Solution Overview

Problem

Conventional twin-configuration circulation pumps face instability in diverter valve positioning due to manufacturing tolerances and different flow paths, leading to hydraulic blocking and inefficient operation, particularly during single-pump mode.

Innovation Solution

Implementing individual control variables for each pump drive and a decoupling control system to stabilize the diverter valve position by compensating for design-related differences and hydraulic coupling, using methods like master-slave control or multi-variable systems with decoupling blocks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a twin pump construction with two electronically controlled circulation pumps is used to maintain high hygiene standards and prevent Legionella growth, then the reliability and hygiene performance improve, but the device complexity and energy consumption increase due to both pumps needing to be controllable and monitorable

Engineering Contradiction:
Improvehygiene performanceVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the control of two circulation pumps into a single unified control unit that manages both pumps electronically. This allows independent control of each pump while maintaining a streamlined control architecture, resolving the contradiction by combining multiple control functions into one integrated system rather than using separate control systems for each pump.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control unit is designed with universal functionality to manage multiple pumps through a single interface. It can selectively activate, monitor, and control either pump or both pumps simultaneously, providing multi-functional capability that reduces overall system complexity while maintaining the ability to prevent Legionella growth through proper circulation management.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a twin pump construction with two electronically controlled circulation pumps is used to maintain high hygiene standards and prevent Legionella growth, then the reliability and hygiene performance improve, but the energy consumption increases due to both pumps needing to be controllable and monitorable

Engineering Contradiction:
Improvehygiene performanceVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control unit dynamically manages pump operation by selectively activating only one pump when sufficient circulation is achieved, and only activating the second pump when additional circulation is needed. This dynamic control strategy ensures hygiene standards are met while minimizing energy consumption by avoiding continuous operation of both pumps simultaneously.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs periodic monitoring and control where the control unit assesses circulation requirements and activates pumps only when needed. This periodic action pattern allows the system to maintain hygiene performance through intermittent pump operation rather than continuous operation, thereby reducing overall energy consumption while ensuring Legionella prevention.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3592978B1Method for operating a circulation pump in a twin pump construction
Publication Date: 2026.05.06 KSB SE & CO KGAA
  • EP3592978B1 patent drawingFigure 1a~1b
  • EP3592978B1 patent drawingFigure 2
  • EP3592978B1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a circulation pump in a twin pump construction, wherein the circulation pump comprises at least two separate individual pumps, the pressure ports of which converge to form a common output pressure port, and wherein at least one changeover flap arranged in the pressure port is provided for switching between single-pump and multi-pump operation, wherein a regulating unit for the circulation pump determines individual manipulated variables for the pump drives of at least two individual pumps in the multi-pump operation in order to stabilize the flap position.