Air Conditioner Drain Pump Speed Control to Reduce Noise

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Solution Overview

Problem

Conventional air conditioners with self-priming drain pumps generate excessive noise due to high-speed impeller operation, particularly in ceiling- or wall-mounted types where space constraints are a factor.

Innovation Solution

The air conditioner incorporates a drain pump system with a water level sensor and controller that adjusts the pump's operational speed and duration based on the condensed water level, optimizing rotational speed to minimize noise while ensuring required performance, including stepwise speed increases and shutdowns when current or torque thresholds are reached.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a self-priming pump is used to pump condensed water in ceiling- or wall-mounted air conditioners, then the pump can operate without sufficient space below the drain pan, but loud noise is generated due to high-speed impeller rotation

Engineering Contradiction:
Improvespace below drain panVSAvoidnoise
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies dynamics by enabling the drain pump to operate at variable speeds rather than a fixed high speed. The controller adjusts the impeller rotation speed dynamically based on the condensed water level detected by the sensor, allowing the pump to maintain effectiveness while minimizing noise generation during low-flow conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the drain pump by introducing variable speed control. The controller modifies the rotation speed parameter of the impeller based on water level conditions, transitioning from constant high-speed operation to adaptive speed operation that reduces noise while maintaining pumping capability

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the drain pump operates at high speed to pump condensed water, then pumping performance is improved, but noise generation increases

Engineering Contradiction:
Improvepumping performanceVSAvoidnoise
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts the impeller speed based on real-time water level sensor feedback. When condensed water level is high, the pump operates at higher speeds for optimal pumping performance; when water level is low, the pump reduces speed to minimize noise, thus dynamically balancing productivity and noise control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements a feedback control mechanism where the water level sensor continuously monitors the condensed water level and sends signals to the controller. The controller adjusts the pump speed based on this feedback, creating a closed-loop system that optimizes pumping performance while reducing noise when full pumping capacity is not required

Inventive Principle:
Principle #23Feedback

3Reliability

If the drain pump operates continuously to discharge condensed water, then water discharge reliability is improved, but energy consumption and noise increase

Engineering Contradiction:
Improvewater discharge reliabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic operation of the drain pump based on water level conditions rather than continuous operation. The pump activates when the water level sensor detects condensed water accumulation and deactivates when the water level drops, creating an on-demand periodic operation pattern that reduces energy consumption while maintaining reliable water discharge

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses the condensed water itself to trigger pump operation through the water level sensor. When water accumulates to a certain level, it automatically activates the pump, and when water is discharged, the level drops and the pump stops, creating a self-regulating operation pattern that ensures reliable discharge without continuous energy input

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 approach significantly reduces noise generation by operating the drain pump at optimal, minimal rotational speeds only when necessary, thereby enhancing operational efficiency and reducing electromagnetic and flow noise.

Implementation Method 1

a drain pump disposed on one side of the drain pan to discharge condensed water collected in the drain pan to the outside of the case

Methodology Applied
Scientific EffectPump: Pump

Data Source

PatentEP4379285A1Air conditioner
Publication Date: 2024.06.05 LG ELECTRONICS INC
  • EP4379285A1 patent drawingFigure 1
  • EP4379285A1 patent drawingFigure 2
  • EP4379285A1 patent drawingFigure 3

AI summary

An air conditioner is disclosed. The air conditioner includes a case including an inlet and an outlet formed therein, a blowing fan disposed in the case to blow air from the inlet to the outlet, a heat exchanger disposed in the case to exchange heat with air flowing in the case, a drain pan disposed below the heat exchanger to collect condensed water falling down from the heat exchanger, and a drain pump disposed on one side of the drain pan to discharge condensed water collected in the drain pan to the outside of the case. When the level of the condensed water reaches the reference level, the drain pump is turned on.