Pressure Limiting Valve for Backflow Preventer Gauge Protection
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Solution Overview
Problem
Current methods for testing backflow preventers lack a suitable pressure limiting valve to protect low pressure gauges from over-pressurization, leading to inaccurate or damaged readings when measuring pressure drops across high-pressure systems.
Innovation Solution
A pressure limiting valve with a flexible rubber diaphragm and opposing springs that separates upper and lower chambers, allowing the low pressure gauge to measure pressure drops without exceeding its maximum rating, while a relief valve and needle valve ensure safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a low pressure gauge is used to measure pressure drops across backflow prevention devices, then measurement precision is improved, but the gauge is damaged by over-pressurization from high-pressure systems
Solution Approach 1:
A pressure limiting valve is introduced as an intermediary device between the high-pressure backflow prevention device and the low-pressure gauge. This valve limits the maximum pressure transmitted to the gauge while allowing accurate measurement of pressure drops, thus protecting the gauge from over-pressurization damage while maintaining measurement precision
Solution Approach 2:
The pressure measurement system is segmented into two functional parts: a pressure limiting mechanism that protects the gauge, and a measurement mechanism that captures pressure drop data. This segmentation allows each component to perform its specific function optimally without compromising the other
2Reliability
If a pressure limiting valve is added to protect the low pressure gauge, then gauge reliability is improved, but device complexity increases
Solution Approach 1:
The pressure limiting valve integrates multiple functions into a single device: it limits maximum pressure, allows pressure drop measurement, and can be configured with opposing springs for precise control. This merging reduces the need for separate protective devices and measurement instruments, thereby managing complexity
3Manufacturing precision
If opposing springs are used in the pressure limiting valve, then pressure control precision is improved, but manufacturing complexity increases
Solution Approach 1:
Opposing springs are used in the pressure limiting valve to create balanced forces that precisely control the pressure threshold. One spring provides the primary limiting force while the opposing spring fine-tunes the pressure control, enabling high precision pressure regulation through mechanical balance rather than complex electronic controls
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
Enables accurate measurement of pressure drops across backflow prevention devices in high-pressure systems without damaging the low pressure gauge, ensuring reliable testing and maintaining gauge integrity.
Implementation Method 1
An upper and a lower chamber are formed from an interior portion of the valve body and are generally separated by a flexible rubber diaphragm
Implementation Method 2
a spring actuable via movement of the flexible diaphragm in response to pressure changes in the valve body to generally bias a closure disc in an open position relative to the outlet
Implementation Method 3
the spring compresses under pressure to permit the closure disc to seal the outlet when pressure in the valve body approximately reaches a maximum PSI rating of the low pressure gauge
Data Source
AI summary
The pressure limiting valve has a low pressure gauge configured to measure the operability of a backflow prevention device having a line pressure relatively higher than the maximum PSI rating of the low pressure gauge. The valve body has an inlet statically coupled to a pressurized fluid source and an outlet coupled to the low pressure gauge. Upper and lower chambers fluidly coupled via a conduit are formed from an interior portion of the valve body and generally separated by a flexible diaphragm. A spring actuable via movement of the flexible diaphragm in response to pressure changes in the valve body biases a closure seat in an open position relative to the outlet when the valve body is not under pressure, and compresses under pressure to permit the closure seat to seal the outlet when pressure in the valve body reaches a maximum PSI rating of the low pressure gauge.