Foam Proportioning System Recirculation Control
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Solution Overview
Problem
Existing fire suppression systems lack an efficient method to automatically proportion chemical foamants in fire fighting applications, particularly in scenarios with varying water flow rates, which can lead to ineffective fire extinguishing and increased water usage.
Innovation Solution
A foam proportioning system that includes a foam pump, foam lines, a divert with recirculation, and a controller to maintain a minimum flow rate of liquid foam concentrate, ensuring optimal foam concentration in water streams across different flow rates, preventing foam pump stalling and adjusting foam injection accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If foam pump operates at low flow rates to match varying water flow rates, then foam concentration can be maintained, but foam pump may stall or experience excessive wear
Solution Approach 1:
A bypass line with control valve is introduced as an intermediary component between the foam pump outlet and the main discharge line. This bypass allows a portion of the foam concentrate to be diverted away from the pump inlet, preventing the pump from stalling at low flow rates while maintaining the required foam concentration in the main water stream.
Solution Approach 2:
The system dynamically adjusts the bypass valve opening based on water flow rate conditions to change the foam concentrate flow parameters. At low water flow rates, the bypass valve opens to reduce foam pump inlet flow and prevent stalling. At higher flow rates, the bypass closes to maximize foam injection efficiency.
2Productivity
If foam pump is sized for high flow rates, then it can handle maximum water flow, but it wastes energy and causes excessive wear at low flow rates
Solution Approach 1:
The bypass line acts as a flow management intermediary that allows the foam pump to operate at its optimal efficiency point even when the main water stream flow rate is low. By diverting excess foam concentrate through the bypass, the pump isn't forced to operate at reduced capacity, thereby minimizing energy waste and mechanical wear.
3Device complexity
If manual foam proportioning is used, then system complexity is reduced, but foam concentration accuracy deteriorates
Solution Approach 1:
The system incorporates flow rate sensing and automated control that provides feedback to the bypass valve actuator. This feedback mechanism continuously monitors water flow conditions and automatically adjusts the bypass valve position to maintain precise foam concentration, eliminating the need for manual intervention while ensuring accurate proportioning.
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 effectively maintains a consistent foam concentration, reducing fire extinguishing time, minimizing water damage, and prolonging foam pump lifespan by automatically adjusting foam injection based on demand, ensuring efficient fire suppression across varying flow rates.
Implementation Method 1
The divert can include a recirculation line having a first end positioned downstream of the foam pump and a second end positioned upstream of the foam pump. The divert can direct a portion of the flow of the liquid foam concentrate downstream of the foam pump back through the foam pump.
Data Source
AI summary
Embodiments of the invention provide a foam proportioning system. The foam proportioning system can include a foam pump, at least one foam line, a divert, and at least one controller. The divert can direct a portion of a flow of a liquid foam concentrate downstream of the foam pump back through the foam pump. The controller, which can be in communication with the foam pump and the divert, can be configured to automatically maintain a minimum flow rate of the liquid foam concentrate through the foam pump.