Sprinkler Nitrogen Fill Control for Fast Refill and Corrosion Resistance
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Solution Overview
Problem
Existing dry pipe fire sprinkler systems face challenges in maintaining nitrogen purity and pressure due to leaks and inefficiencies in nitrogen generation, leading to potential corrosion and system failures, which are exacerbated by the use of atmospheric air and traditional air compressors.
Innovation Solution
A gas supply system with a control system that automatically switches between nitrogen generation and air bypass modes based on pressure demands, using a separation system, compressor, bypass valve, and sensor to maintain optimal gas composition and pressure in the sprinkler system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitrogen generation is used to maintain supervisory pressure in dry pipe sprinkler systems, then corrosion is reduced due to lower oxygen content, but the filling speed is insufficient to meet NFPA 13 requirements of 30 minutes
Solution Approach 1:
The system dynamically switches between two operational modes: nitrogen generation mode for normal pressure maintenance and air compressor bypass mode for rapid refilling. The control system monitors system needs and adjusts the gas supply method in real-time, allowing the system to optimize between corrosion protection and filling speed based on current conditions
Solution Approach 2:
The gas supply system is designed to perform multiple functions through a single integrated setup: it can generate nitrogen for corrosion prevention, rapidly refill using atmospheric air when needed, and automatically transition between these modes. The bypass valve and control system enable this multi-functionality, allowing the same infrastructure to serve both protective and rapid-response needs
2Productivity
If atmospheric air is used to refill the sprinkler system, then filling speed increases, but oxygen content rises causing corrosion
Solution Approach 1:
The system uses periodic nitrogen generation to maintain low oxygen levels after initial refilling. The control system monitors oxygen content and pressure, periodically switching between air refilling and nitrogen generation to keep oxygen levels below corrosion-threshold concentrations while maintaining supervisory pressure
Solution Approach 2:
The control system continuously monitors system pressure and oxygen content, using this feedback to determine when to switch between air refilling and nitrogen generation modes. This closed-loop control ensures that atmospheric air is introduced only when necessary for rapid refilling, and nitrogen generation is activated to restore protective low-oxygen conditions
3Productivity
If nitrogen generators are sized to fill the system within 30 minutes, then NFPA 13 requirements are met, but the system becomes prohibitively expensive and complex
Solution Approach 1:
The refilling function is segmented into two parts: a small nitrogen generation system for normal pressure maintenance and corrosion protection, and a larger air compressor that provides rapid refilling capability when needed. This segmentation allows each component to be sized appropriately for its specific function, avoiding the need for an oversized and expensive nitrogen generator
4Reliability
If nitrogen generators are used, then corrosion is minimized, but the system cannot respond quickly to large leaks or maintenance requirements
Solution Approach 1:
The system pre-positions both nitrogen generation capability and air compressor bypass capability, so that when a large leak or maintenance event occurs, the control system can immediately switch to the air compressor for rapid refilling without delay. This preliminary preparation of multiple response options ensures both corrosion protection during normal operation and rapid response when needed
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 system ensures rapid filling and maintenance of nitrogen pressure, reduces corrosion, and prevents system failures by efficiently managing gas supply, even in the presence of leaks, thus meeting NFPA requirements and ensuring system integrity.
Implementation Method 1
a separation system for obtaining nitrogen from atmospheric air and supplying the nitrogen to the reservoir tank
Implementation Method 2
a compressor, for supplying atmospheric air
Data Source
AI summary
A gas supply system primarily designed for use with fire sprinkler systems which includes a control system which uses flow demand to automatically determine the mode of operation and switch between providing air and nitrogen. The gas supply system can operate either in standard nitrogen generation mode where nitrogen is supplied to the reservoir tank and/or sprinkler system or in a bypass mode, where sufficient pressure is only obtained by directly supplying air. The gas supply system can provide for improved safety in operation as well as the ability to operate the sprinkler system primarily when filled with nitrogen supervisory gas.