Titanium Spa Heater Element Retention Without Welded Fittings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing spa heater elements are susceptible to corrosion when exposed to corrosive spa chemicals, and using titanium heater elements with machined or welded fittings increases costs due to material expense and potential for further corrosion.
Innovation Solution
A spa heater design featuring a titanium outer wall with stamped or formed indentations for clip retention, combined with O-rings, stepped washers, snap rings, and caps for secure and corrosion-resistant attachment, allowing a thin single outer wall without the need for additional support structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compression fittings are used to hold the heater element, then the heater element can be retained, but pressure is applied on the titanium outer wall requiring either a thick outer titanium wall or a second wall under the outer titanium wall to support it
Solution Approach 1:
The retention mechanism is segmented into multiple functional components: O-rings for sealing, stepped washers for load distribution, snap rings for mechanical retention, and clips for positioning. This segmentation allows each component to perform its specific function without requiring a thick or double-walled structure.
Solution Approach 2:
Stepped washers act as intermediaries between the compression fittings and the titanium outer wall, distributing the applied pressure over a larger area. This intermediary component enables the use of a thin outer wall by preventing stress concentration that would otherwise require wall thickening.
2Strength
If a thick outer titanium wall or double wall is used to support the outer titanium wall, then the heater element can withstand compression fitting pressure, but cost increases
Solution Approach 1:
The patent uses inexpensive support components (stepped washers, snap rings, O-rings) that can be easily manufactured and replaced if needed, rather than investing in expensive thick or double-walled titanium structures. These auxiliary components provide the necessary structural support at minimal cost.
Solution Approach 2:
The solution combines titanium outer wall with complementary materials for support structures (stainless steel or other alloys for snap rings, washers, and caps). This composite approach allows the expensive titanium to be used only where corrosion resistance is critical, while cheaper materials provide structural support.
3Reliability
If welding is used to attach fittings to the titanium heater element, then the heater element can be securely attached, but the metal close to the welds becomes more susceptible to corrosion
Solution Approach 1:
The patent replaces welding (thermal process) with mechanical attachment methods including snap rings, O-rings, stepped washers, and compression fittings. This substitution eliminates the heat-affected zone and associated corrosion vulnerability while maintaining secure attachment through mechanical means.
Solution Approach 2:
Stepped washers and snap rings serve as intermediary components between the attachment mechanism and the titanium heater element. These intermediaries distribute mechanical stresses without requiring direct welding to the titanium, thereby preventing corrosion at the attachment points.
4Reliability
If machined titanium fittings are used to attach the titanium heater element, then the heater element can be securely attached, but the cost increases due to machining expense
Solution Approach 1:
The patent uses inexpensive standard components (snap rings, O-rings, washers, caps) that can be manufactured through simple processes rather than expensive titanium machining. These components provide secure attachment at a fraction of the cost of machined titanium fittings.
Solution Approach 2:
The attachment system is segmented into multiple simple components that can be manufactured independently using low-cost processes, rather than requiring a single complex machined titanium fitting. This segmentation enables cost-effective manufacturing while maintaining attachment security.
Data Source
AI summary
A spa heater includes a heater element having a single outer wall with indentations near each end for receiving clips for positioning the heater element. The indentations are preferably stamped or formed by some other method which does not weaken the outer wall and the heater element is retained by use of the clips in the indentations. Incorporation of the indentations and the clips allows use of a single thin outer wall thereby reducing cost. The heater element is held and sealed by a combination of O-rings, stepped washers, snap rings clips, and caps. An electrical connection may be made using ring type wire ends residing under the caps or by connecting to posts extending from the ends of the heater element. The heater element is preferably a spiral heater element and a titanium outer wall may be used to resist corrosion and increases heater element life.