Heated Centrifugal Pump Cover for Dry-Run Fault Protection
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Solution Overview
Problem
Existing heaters for household appliances, particularly centrifugal pumps, face challenges in dry operation management, where the safety device can fail catastrophically, leading to pump damage, and there is a need for improved energy efficiency and reliability.
Innovation Solution
A cover for a centrifugal pump with an electric resistor that directly contacts the liquid, featuring a heating stretch on the inner face and end stretches on the outer face, equipped with a temperature-sensitive control device and safety device, allowing for optimized heat exchange and enhanced fault management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the resistor is in direct contact with the water, then heat exchange efficiency is improved, but the risk of damage from safety device failure increases
Solution Approach 1:
The patent introduces a cover as an intermediary component between the resistor and water. The cover allows the resistor to be positioned close to the water for efficient heat transfer while maintaining a physical barrier that protects the resistor from direct water contact and potential damage during dry operation or safety device failures.
Solution Approach 2:
The heating element is segmented into a heating stretch that contacts the water through the cover and end stretches that remain isolated. This segmentation allows different portions of the resistor to serve different functions: efficient heating when in use, and protection during abnormal conditions.
2Device complexity
If the control device is sensitive only to water temperature, then the heating control is simple, but the protection against dry operation failures is insufficient
Solution Approach 1:
The control device is equipped with dual temperature sensing capabilities: one sensor monitors water temperature for normal heating control, while another sensor monitors resistor temperature to detect dry operation conditions. This feedback mechanism enables the system to distinguish between normal operation and abnormal conditions, triggering appropriate responses.
Solution Approach 2:
The control device is designed to detect potential dry operation failures before they cause catastrophic damage by monitoring resistor temperature in advance. When abnormal temperature rise is detected, the system can preemptively shut down or alert, preventing safety device failure.
3Reliability
If the resistor is completely isolated from water by the cover, then safety is improved, but heat exchange efficiency deteriorates
Solution Approach 1:
The cover design implements local quality by allowing selective heat transfer: the heating stretch portion of the resistor is positioned to enable efficient thermal contact with water through the cover material, while the end stretches remain isolated. This localized approach optimizes both safety and efficiency in different regions of the same component.
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 design ensures reliable operation by preventing damage from safety device failures, optimizing heat exchange, and reducing lime scale accumulation, while being energy-efficient and cost-effective.
Implementation Method 1
an electric resistor for heating the liquid
Implementation Method 2
at least one control device sensitive both to the temperature of the liquid and to the temperature of the electric resistor
Implementation Method 3
at least one safety device sensitive to the temperature of the electric resistor
Implementation Method 4
a first portion of the heating stretch is in contact with the inner face
Data Source
AI summary
A cover (1) for a centrifugal pump which comprises a heating element (8), which has a heating stretch (10) and two end stretches (12) connected to the heating stretch (10), wherein the heating element (8) crosses the cover (1) so that the heating stretch (10) is under the cover (1) and the two end stretches (12) are over the cover (1), wherein at least one safety device (20), sensitive to the temperature of the electric resistor (8), fixed to the outer face (6), is provided and at least one control device (22), sensitive to both the temperature of the liquid and the temperature of the electric resistor (8), fixed to the outer face (6), is provided, wherein at least one first portion (14) of the heating stretch (10) is in contact with the cover (1), so that the heating stretch (10) is adapted to be contact with the liquid.