Plastic Sprinkler Adapter With Dissimilar Threads for Leak-Tight Sealing
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Solution Overview
Problem
Existing fire protection sprinkler fittings face challenges in forming a sealed threaded engagement between plastic and metal components without reinforcement, which can lead to compromised fluid tight seals and altered flow characteristics due to excessive torque or improper orientation.
Innovation Solution
A self-supporting plastic sprinkler adapter with a receptacle featuring internal straight threads and a gasket chamber that maintains fluid tight seals and flow characteristics without the need for metal inserts or reinforcements, allowing for rotational orientation of the sprinkler while preventing radial forces that damage threads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a plastic sprinkler fitting uses internal threaded engagement with a metal sprinkler, then the connection can be formed, but excessive torque damages the plastic threads and compromises the fluid tight seal
Solution Approach 1:
The patent combines plastic and metal materials in a composite structure where a metal reinforcement insert is embedded within the plastic fitting. This composite construction provides the thread engagement strength of metal while maintaining the corrosion resistance and ease of installation of plastic, thereby preventing thread damage and ensuring reliable fluid tight seals under torque loading.
Solution Approach 2:
The patent applies metal reinforcement locally at the threaded engagement area rather than making the entire fitting from metal. The reinforcement insert is positioned specifically where thread strength is needed, providing localized strengthening without compromising the overall plastic construction's advantages.
2Reliability
If a gasket is compressed to form a fluid tight seal in a plastic fitting, then sealing is achieved, but the gasket distortion alters flow characteristics through the fitting
Solution Approach 1:
The patent introduces a specifically designed gasket as an intermediary sealing element that is compressed between the fitting body and the sprinkler. The gasket material and geometry are selected to provide adequate sealing compression without excessive distortion that would interfere with fluid flow paths, thus mediating between the sealing requirement and flow characteristic preservation.
3Reliability
If a sprinkler is over-torqued to ensure proper seal, then sealing is improved, but the sprinkler threads or body are damaged
Solution Approach 1:
The patent incorporates a gasket as a cushioning element that is compressed during the tightening process. This gasket acts as a buffer that absorbs excess torque, protecting the sprinkler threads and body from damage while still achieving the necessary seal compression. The gasket deforms in a controlled manner to prevent thread stripping or body cracking.
4Strength
If metal reinforcement inserts are added to plastic fittings, then thread strength is improved, but device complexity increases
Solution Approach 1:
The patent merges the plastic fitting body and metal reinforcement insert into a single integrated component through embedding or overmolding processes. This combining of materials and functions into one unified part strengthens the threaded engagement while avoiding the complexity of separate assembly steps, making the reinforcement as inherent to the fitting as the plastic material itself.
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 adapter ensures a fluid tight seal and maintains rated flow characteristics of the sprinkler, allowing for infinite rotational positioning without compromising the connection, and withstands pressures up to 2300 psi without additional reinforcement.
Implementation Method 1
the sprinkler compresses a gasket within an internal gasket retention area of the fitting
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A two member plastic pipe fitting adapter for installing a threaded sprinkler head. The members are coupled together to form a chamber for housing an annular gasket. The gasket chamber includes an expansion void and bearing surfaces for the gasket. The adapter includes a receptacle with an internal thread for engagement with a sprinkler head to load the gasket and form a fluid tight seal. The engagement between the sprinkler and the adapter is formed by dissimilar threads to minimize the outward radial forces on the adapter.