Arc Lamp Bulb Cooling via Forced Convection
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Solution Overview
Problem
Arc lamp bulbs experience excessive residual stress due to thermal creep, exacerbated by high UV output power, leading to premature breakage, as traditional natural convection cooling results in asymmetric temperature profiles and operating temperatures above 750°C.
Innovation Solution
An apparatus and method for actively cooling arc lamp bulbs by distributing heat evenly across the surface using a pilot jet assembly with straight or inclined fluid directing jets, which direct cooling fluids to adhere to the bulb surface, reducing thermal stress and maintaining temperatures below 600°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If natural convection cooling is used, then the cooling system is simple, but the temperature profile becomes highly asymmetric and operating temperature exceeds 750°C
Solution Approach 1:
The patent applies forced convection cooling using a cooling fluid (gas or liquid) circulated through channels in the bulb wall and/or impinged directly onto the bulb surface. This hydraulic approach replaces natural convection, enabling precise temperature control below 600°C by actively managing heat removal through controlled fluid flow.
Solution Approach 2:
The patent changes the cooling mechanism from passive natural convection to active forced convection with controllable parameters. By adjusting cooling fluid flow rate, temperature, and distribution patterns, the system achieves uniform temperature profiles and maintains operating temperatures below the 600°C threshold, preventing thermal creep stress.
2Device complexity
If natural convection cooling is used, then the cooling apparatus is simple, but thermal stress buildup occurs quickly
Solution Approach 1:
The patent implements forced convection cooling systems with cooling fluid circulation channels integrated into the bulb structure or directed onto the bulb surface. This active cooling approach ensures uniform heat removal, maintaining temperature gradients below thresholds that cause thermal creep, thereby preventing bulb failure and extending operational reliability.
Solution Approach 2:
The patent transforms the cooling system from passive to active with controllable parameters. By regulating cooling fluid flow rate, temperature, and distribution uniformity, the system maintains bulb temperature below 600°C, preventing rapid residual stress accumulation and improving overall bulb reliability and lifetime.
3Productivity
If high UV output power is used, then the lamp productivity increases, but thermal creep stress increases leading to bulb breakage
Solution Approach 1:
The patent implements forced convection cooling systems that actively remove heat from the bulb during high-power UV operation. Cooling fluid circulated through bulb wall channels or directed onto the surface dissipates thermal energy, maintaining temperature gradients below thresholds that cause thermal creep, enabling high productivity operation without bulb failure.
Solution Approach 2:
The patent introduces active temperature control parameters to decouple UV output power from bulb temperature. By independently controlling cooling fluid flow rate and temperature, the system allows high-power operation for maximum productivity while maintaining bulb temperature below 600°C, preventing thermal stress-induced breakage.
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 solution effectively reduces thermal stress and extends the operational lifetime of arc lamps by maintaining a uniform temperature profile, preventing bulb breakage and ensuring safe operating conditions.
Implementation Method 1
Traditionally, bulbs rely on natural convection for cooling. A cooling fluid may be circulated through channels in the bulb wall and/or impinged onto the bulb surface.
Implementation Method 2
A cooling fluid may be circulated through channels in the bulb wall and/or impinged onto the bulb surface, redistributing heat more uniformly across the bulb surface.
Data Source
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AI summary
A fluid input manifold distributes injected fluid around the body of a bulb to cool the bulb below a threshold. The injected fluid also distributes heat more evenly along the surface of the bulb to reduce thermal stress. The fluid input manifold may comprise one or more airfoils to direct a substantially laminar fluid flow along the surface of the bulb or it may comprise a plurality of fluid injection nozzles oriented to produce a substantially laminar fluid flow. An output portion may be configured to facilitate fluid flow along the surface of the bulb by allowing injected fluid to easily escape after absorbing heat from the bulb or by applying negative pressure to actively draw injected fluid along the surface of the bulb and away.