Vertical Piston Backflow Prevention With Low Pressure Loss

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Solution Overview

Problem

Conventional backflow prevention devices, such as reduced pressure zone (RPZ) devices, suffer from significant pressure loss (6 to 10 psi) that can lead to inadequate water supply, especially in tall buildings, and are prone to false discharge due to pressure fluctuations, requiring costly testing and being inefficient in space usage and prone to debris-induced failures.

Innovation Solution

A backflow prevention device with a vertically installed piston that moves between normal and backflow positions, reducing pressure loss and preventing false discharges, featuring a vertically oriented design to minimize debris entrapment and allowing for efficient testing with a standard pressure gauge, and optionally incorporating springs to bias the piston towards the backflow position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional RPZ device is used, then backflow prevention is achieved, but significant pressure loss (6 to 10 psi) occurs leading to inadequate water supply

Engineering Contradiction:

Improvebackflow preventionVSAvoidpressure loss

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The invention extracts and eliminates the relief valve component from the conventional RPZ device. By removing this pressure-reducing element, the device maintains higher downstream pressure (reducing pressure loss) while still providing backflow prevention through the check valve mechanism alone.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the pressure parameter characteristics by eliminating the relief valve that normally reduces pressure. This allows the device to operate with minimal pressure loss (less than 6 psi) while maintaining backflow prevention functionality through modified check valve operation.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a conventional RPZ device is used, then backflow prevention is achieved, but false discharge occurs due to pressure fluctuations requiring costly testing

Engineering Contradiction:

Improvebackflow preventionVSAvoidfalse discharge

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention removes the relief valve that causes false discharge during pressure fluctuations. By extracting this component, the device eliminates the source of unnecessary water discharge while maintaining backflow prevention through the check valve mechanism.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention simplifies testing requirements, making the device more economical to maintain. By eliminating the relief valve, routine testing is no longer needed, reducing maintenance costs and complexity.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If a conventional RPZ device is used, then backflow prevention is achieved, but excessive space is consumed due to horizontal installation requirement

Engineering Contradiction:

Improvebackflow preventionVSAvoidinstallation space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The invention changes the installation orientation from horizontal to vertical. This dimensional change reduces the horizontal space required for installation while maintaining backflow prevention functionality, allowing the device to fit in tighter spaces.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 device effectively prevents backflow while minimizing water discharge during normal conditions and reducing pressure loss, allowing for efficient testing and easy maintenance, and can be installed vertically to prevent debris-induced failures, addressing the inefficiencies of conventional RPZ devices.

Implementation Method 1

The piston is configured to move to the normal position in response to normal flow through the device passage from the inlet port toward the outlet port and configured to move to the backflow position in response to greater pressure in the middle segment than in the inlet port

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS11746509B2Backflow prevention device

Publication Date: 2023.09.05 BASSETT KENNY

AI summary

A backflow prevention device includes a piston received in a device passage between an inlet port and outlet port. A relief port can fluidly communicate with a middle segment of the device passage. The piston is movable between a normal flow position in which the piston blocks fluid communication between the relief port and the middle segment of the device passage and a backflow position in which the piston allows fluid communication between the relief port and the middle segment of the device passage. The piston can move to the normal position in response to normal flow through the device passage from the inlet port toward the outlet port and configured to move to the backflow position in response to greater pressure in the middle segment than in the inlet port.