Condensate Pump Low-Load Detection Using Phase-Cutting Control

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Solution Overview

Problem

Existing condensate collection systems in appliances like laundry drying machines and air conditioners face issues with high energy consumption and maintenance costs due to the use of float sensors for detecting low load conditions, which can lead to inefficient pump operation and potential overflowing.

Innovation Solution

A method for detecting low load conditions in a synchronous electric motor-driven pump that uses phase-cutting control to measure variations in firing angles and compares these variations to a predefined threshold, allowing for efficient operation without sensors and reducing energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a float sensor is used to detect low load conditions, then the pump operation can be controlled, but the manufacturing cost increases and the device complexity increases

Engineering Contradiction:
Improvepump operation controlVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical float sensor system with an electrical detection system. The control board detects pump load conditions by monitoring electrical parameters (current, power consumption) of the motor-driven pump, eliminating the need for mechanical float sensors and their associated cabling. This substitution reduces device complexity while maintaining operational control reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The pump system performs self-detection of its own load conditions through the control board monitoring electrical parameters. The system uses its own operational characteristics (electrical consumption patterns) to determine when the condensate tank is full or when the pump is running dry, eliminating the need for separate detection components.

Inventive Principle:
Principle #25Self-service

2Reliability

If a float sensor is used to detect low load conditions, then the pump operation can be controlled, but the manufacturing cost increases

Engineering Contradiction:
Improvepump operation controlVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical float sensor system with an electrical detection system. The control board detects pump load conditions by monitoring electrical parameters (current, power consumption) of the motor-driven pump, eliminating the need for mechanical float sensors and their associated cabling. This substitution reduces device complexity while maintaining operational control reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The pump system performs self-detection of its own load conditions through the control board monitoring electrical parameters. The system uses its own operational characteristics (electrical consumption patterns) to determine when the condensate tank is full or when the pump is running dry, eliminating the need for separate detection components.

Inventive Principle:
Principle #25Self-service

3Productivity

If the pump is activated for a predetermined time interval, then the bottom tank can be emptied, but the energy consumption increases when the tank is already empty

Engineering Contradiction:
Improvetank emptying efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The control board continuously monitors the pump's electrical parameters during operation and uses this feedback to detect when the pump is running dry (empty tank condition). When the feedback indicates zero or minimal load, the system immediately interrupts pump operation, preventing unnecessary energy consumption while ensuring complete tank emptying when liquid is present.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from a static, fixed-duration pump activation scheme to a dynamic control system that continuously adjusts pump operation based on real-time load detection. The pump runs for the necessary duration to empty the tank, then automatically stops when the empty condition is detected, optimizing energy usage according to actual operational needs.

Inventive Principle:
Principle #15Dynamics

4Device complexity

If the pump operates with a fixed activation time, then the control is simple, but the energy consumption is high and the productivity decreases

Engineering Contradiction:
Improvecontrol simplicityVSAvoidenergy consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The control board continuously monitors the pump's electrical parameters during operation and uses this feedback to detect when the pump is running dry (empty tank condition). When the feedback indicates zero or minimal load, the system immediately interrupts pump operation, preventing unnecessary energy consumption while ensuring complete tank emptying when liquid is present.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from a static, fixed-duration pump activation scheme to a dynamic control system that continuously adjusts pump operation based on real-time load detection. The pump runs for the necessary duration to empty the tank, then automatically stops when the empty condition is detected, optimizing energy usage according to actual operational needs.

Inventive Principle:
Principle #15Dynamics

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 method effectively determines low load conditions without sensors, reducing energy consumption and maintenance costs, and prevents overflowing by accurately interrupting pump operation when the condensate collection system is full, thereby ensuring efficient condensate collection.

Implementation Method 1

a feedback setpoint thereof being a condition of minimum phase-shift between current supplying the windings of the electric motor and generated counter-electromotive force

Methodology Applied
Scientific EffectCounter-electromotive force: Electromagnetic Induction

Data Source

PatentEP2902630B1Method for detecting a low-load condition in a pump, in particular a condensate discharge pump embodied in a condensate collection system, and motor-pump assembly
Publication Date: 2018.01.03 ASKOLL HLDG SRL
  • EP2902630B1 patent drawingFigure 1~2
  • EP2902630B1 patent drawingFigure 3
  • EP2902630B1 patent drawingFigure 4

AI summary

Method (400) for detecting a low load condition of a pump actuated by a synchronous electric motor, comprising the following steps: - steady-state driving of said electric motor (1) by means of phase-cutting control, a feedback setpoint thereof being a condition of minimum phase-shift between current supplying the windings of the electric motor (1) and generated counter-electromotive force; - detecting (430, 440) at least two firing angles (α0, α1) successively applied, in relation to said phase-cutting control, during two successive half-periods of a voltage supplying the electric motor; - calculating (450) at least one variation (Δα) between two consecutive firing angles (α0, α1) previously detected; - comparing (490) said variation (Δα), or the sum of said successive variations (∑Δα), with a threshold value (Δαmax), where reaching or exceeding said threshold value (Δαmax) identifies said low load condition.