Optical Cable Float Switch for Hazardous Area Control
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Solution Overview
Problem
In hazardous environments, such as pumping stations with flammable or volatile gases/liquids, conventional float switches pose a spark hazard due to electrical currents, and ultrasonic level detection systems are complex and costly for remote signaling of pump activation/deactivation.
Innovation Solution
An optically activated switch using fiber optic cables to transmit a light beam from outside the hazardous area to a switch within the environment, allowing manual control of devices without electrical currents, utilizing a floatable housing with a separator assembly to interrupt or modify the light path based on position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional float switches with electrical currents are used in hazardous environments, then pump activation/detachment can be achieved, but spark hazard and explosion risk increase
Solution Approach 1:
The patent replaces the electrical switch mechanism with an optical detection system. A light source and light detector are positioned to detect the presence or absence of light through a float mechanism, eliminating electrical currents from the hazardous environment while maintaining reliable pump activation/detachment functionality
Solution Approach 2:
The patent introduces light as an intermediary medium to transmit information from the float position to the detection system. The light beam serves as a safe mediator that carries positional information without presenting spark hazards, replacing the direct electrical contact mechanism
2Reliability
If ultrasonic level detection is used for remote signaling, then pump activation can be detected, but system complexity and cost increase
Solution Approach 1:
The patent extracts the essential function of level detection from complex ultrasonic systems to a simple optical mechanism. By using a light source and detector with a float, the system achieves remote signaling capability through a much simpler configuration, removing unnecessary complexity while maintaining reliability
Solution Approach 2:
The patent employs inexpensive optical components (light source, light detector, and simple float) instead of costly ultrasonic equipment. The simple optical system provides adequate functionality for pump activation detection at a lower cost and reduced complexity
3Ease of operation
If manual activation devices are placed in hazardous areas, then operator control is improved, but explosion-proof housings are required increasing complexity
Solution Approach 1:
The patent replaces electrical manual activation devices with an optical control system. The operator can control the system through light-based activation that does not require explosion-proof housings, as the optical components present no spark hazards, thereby improving ease of operation without the complexity of specialized housing requirements
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 optical switch eliminates the risk of electrical sparks and reduces system complexity by enabling manual device activation/deactivation within hazardous areas without the need for explosion-proof housings, ensuring safety and cost-effectiveness.
Implementation Method 1
uses a light beam from a transmitter located outside of the hazardous atmosphere which travels through a light carrying cable, fiber, tube or light guide
Implementation Method 2
a floatable housing and used to signal the need to operate a pump or other device... Based on the position or 'status' of the switch (optical path interrupted, or optical path complete)
Data Source
AI summary
An optical switch having a housing and optical fibers connectable to a light source and a light detector. The light source and light detector are located remote from the housing. The first and second light guide cables have distal ends positioned in a separator assembly and are optically aligned but separated by a gap. The switch includes a device to modify a light beam, and the device is usually adapted to removably occupy the gap. The switch may be embodied in a float.