Endoscope Heater Control with Mechanical Fail-Safe Switch
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Solution Overview
Problem
Conventional endoscope temperature control systems fail to reliably prevent fogging at the distal end when a component failure occurs, leading to incorrect temperature control and potential overheating.
Innovation Solution
A temperature control apparatus for an endoscope that includes a heater, a semiconductor switch, a mechanical switch, and a control section to perform heating stopping control based on temperature detection results, ensuring safe operation even if a component fails, by using a mechanical relay to prevent excessive heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional temperature control system with a single semiconductor switch is used, then the device complexity is low, but the reliability deteriorates because a single point of failure can cause incorrect temperature control and potential overheating
Solution Approach 1:
The patent divides the single switching function into two separate semiconductor switches (first and second switching elements) that operate in a complementary manner. This segmentation allows the system to detect failures in individual switches and respond appropriately, thereby improving reliability while maintaining manageable complexity through modular failure detection circuits.
Solution Approach 2:
The patent implements beforehand cushioning by providing a mechanical switch that serves as a fail-safe mechanism. This mechanical switch is positioned to automatically interrupt the power supply to the heater if both semiconductor switches fail or if a failure is detected, preventing overheating before it can cause damage. This pre-positioned safety mechanism ensures reliability without requiring complex real-time control systems.
2Object-affected harmful factors
If heating control is performed without a mechanical fail-safe switch, then the device complexity is low, but the object-generated harmful factors worsen due to potential excessive heating and thermal damage when component failures occur
Solution Approach 1:
The mechanical switch is pre-configured in the circuit to act as a passive fail-safe mechanism. It remains in the closed position during normal operation but can automatically open to interrupt power supply if overheating is detected or if semiconductor switches fail. This beforehand cushioning approach eliminates active control complexity while providing robust protection against thermal damage.
Solution Approach 2:
The mechanical switch serves as an intermediary safety mechanism between the semiconductor switches and the heater. It mediates the power supply by providing a physical, failure-resistant switching action that can independently interrupt power flow if electronic control fails, thereby protecting against thermal damage without requiring complex integration with the electronic control system.
3Reliability
If only semiconductor switches are used for temperature control, then the ease of operation is high, but the reliability deteriorates because semiconductor switches may fail without providing automatic fail-safe protection
Solution Approach 1:
The system implements self-service through automatic failure detection circuits that monitor the state of semiconductor switches and automatically trigger the mechanical fail-safe switch when failures are detected. This self-monitoring and self-correcting mechanism maintains ease of operation by eliminating the need for manual intervention while ensuring reliability through automatic protection against semiconductor switch failures.
Solution Approach 2:
The patent partially replaces mechanical switching with semiconductor switches for routine temperature control operations, improving ease of operation and control precision. However, it retains a mechanical switch as a fail-safe backup, creating a hybrid system that combines the advantages of electronic control with the inherent reliability of mechanical failure protection.
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
The apparatus effectively prevents fogging and maintains a safe temperature range at the endoscope's distal end, ensuring reliable operation and preventing thermal damage, even in the event of component failures.
Implementation Method 1
a heater arranged in the endoscope, the heater being heated as a result of supply of power
Implementation Method 2
a temperature detection section that detects a temperature of an object to be heated, the object to be heated being heated by the heater
Data Source
Figure 1
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AI summary
A temperature control apparatus for an endoscope includes: a heater; a power circuit connected to a power source, the power circuit generating power to be supplied to the heater and supplying the generated power to the heater via a power line; a temperature detection section that detects a temperature of an object to be heated, the object to be heated being heated by the heater; a semiconductor switch provided on the power line, the semiconductor switch performing switching between supply and shut off of the power to the heater; a control section that controls the semiconductor switch according to a temperature detection result from the temperature detection section to perform temperature control for the object to be heated, and performs heating stopping control to turn the semiconductor switch off based on the temperature detection result; a mechanical switch provided on a line for power supply from the power source to the heater, the mechanical switch performing switching between continuity and shut off of the line; and a heating stopping circuit that if an abnormality occurs in temperature control for the heater, performs heating stopping control to turn the mechanical switch off.