Roots Blower Venturi Feedback for Discharge Noise Suppression

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Solution Overview

Problem

Roots blowers produce significant noise due to rapid opening of trapped pockets at discharge, causing pressure pulsations, which are often mitigated by large and costly silencers.

Innovation Solution

Implementing venturi feedback loops to gradually equalize pocket pressure with discharge pressure, reducing sudden pressure changes and noise by using venturi feedbacks to connect the discharge to the pocket, allowing for smoother operation and reduced noise levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional silencing methods are used to reduce noise from pressure pulsations, then noise is reduced, but package size and cost increase

Engineering Contradiction:

ImprovenoiseVSAvoidpackage size

Core Design Contradiction:

Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The venturi feedback loop performs preliminary action by gradually equalizing pocket pressure with discharge pressure before the pocket opens at discharge. This pre-equalization prevents sudden pressure changes and reduces noise at the source, eliminating the need for downstream silencing equipment and reducing overall package size.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention converts the harmful rapid pressure change into a beneficial gradual pressure equalization process. By using the venturi feedback mechanism, the sudden pressure pulsation that causes noise is transformed into a controlled, gradual pressure equalization, reducing noise without requiring additional silencing components.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If traditional silencing methods are used to reduce noise from pressure pulsations, then noise is reduced, but cost increases

Engineering Contradiction:

ImprovenoiseVSAvoidcost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The venturi feedback loop creates a self-regulating system where the pressure equalization process is automatic and self-controlled. The system uses its own discharge pressure to feedback and control the pocket pressure equalization, eliminating the need for external control systems or additional noise reduction components.

Inventive Principle:

Principle #25Self-service

3Stress or pressure

If pocket pressure equalization is implemented using venturi feedback loops, then pressure pulsations are reduced, but device complexity increases

Engineering Contradiction:

Improvepressure pulsationsVSAvoiddevice complexity

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

The invention uses pneumatic principles through the venturi feedback loop to achieve pressure equalization. The venturi effect creates a pressure differential that drives the feedback mechanism, using gas dynamics to automatically equalize pocket pressure with discharge pressure without mechanical moving parts or complex control systems.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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

Significantly reduces pressure pulsations and noise, potentially eliminating the need for discharge silencers and allowing for a quieter, more efficient operation with minimal size and weight impact.

Implementation Method 1

Incorporation of venturi feedback loops that gradually equalize pocket pressure with discharge pressure, reducing sudden pressure changes and noise through a throttle-like mechanism

Methodology Applied

Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentUS12624693B2Positive displacement roots blower noise suppression

Publication Date: 2026.05.12 INGERSOLL RAND IND US INC

AI summary

A positive displacement roots blower can include a housing having an inlet structured to receive an incoming flow of a fluid, an outlet structured to receive an outgoing flow of the fluid, and a passage. The positive displacement roots blower can also include a pair of intermeshed rotating members supported for complementary rotation within the housing, where the rotating members and the housing form respective operating volumes there between which rotate with the rotating members. Each of the respective operating volumes has the following regions: (1) open to inlet/closed to outlet; (2) closed to inlet/closed to outlet; and (3) closed to inlet/open to outlet. The passage includes a restriction and connects to at least one of the operating volumes when the at least one of the respective operating volumes is in region (2). The restriction can be a venturi feedback connecting to the outlet.