Roots Vacuum Pump Flap Valve for Noise and Space Reduction

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Solution Overview

Problem

Roots vacuum pumps face limitations in delivery capacity due to maximum pressure differences, leading to thermal overload and noise issues when bypass valves open abruptly, requiring larger poppet valves that increase space and cost, and are position-dependent.

Innovation Solution

A pivotable flap valve with a spring-loaded design that automatically opens when the maximum pressure difference is exceeded, reducing moving mass and noise, allowing for smaller housing dimensions and flexible installation, and eliminating the need for hydraulic damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a spring-loaded poppet valve with hydraulic damper is used to reduce noise and prevent damage, then operating noise is reduced and pump housing damage is avoided, but the valve becomes sluggish and requires large moving masses

Engineering Contradiction:

Improveoperating noise and pump housing damageVSAvoidvalve opening speed

Core Design Contradiction:

Object-affected harmful factorsVSSpeed

Solution Approach 1:

The patent extracts the harmful hydraulic damping mechanism from the valve system and replaces it with a purely mechanical spring-loaded design. The valve disk is directly connected to the spring without any hydraulic damper components, allowing the valve to open rapidly when the spring force overcomes the pressure differential, thus eliminating the sluggishness caused by hydraulic resistance while still controlling noise through proper spring selection and valve geometry

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using hydraulic damping to slow down the valve disk movement, the patent inverts the approach by using spring force to accelerate the valve opening. The spring is compressed during valve closure and rapidly expands to open the valve, converting the damping concept into an active opening mechanism that improves response speed

Inventive Principle:

Principle #13The other way round (Inversion)

2Quantity of substance

If large poppet valves are used to handle sufficient medium flowback in large-volume Roots pumps, then sufficient medium flowback is achieved, but the pump housing dimensions and costs increase

Engineering Contradiction:

Improvemedium flowback quantityVSAvoidpump housing volume

Core Design Contradiction:

Quantity of substanceVSVolume of stationary object

Solution Approach 1:

The patent changes the valve type from a traditional poppet valve to a flap valve with a different geometric configuration. The flap valve has an optimized shape that allows medium to flow around it more efficiently, increasing the effective flow area without increasing the valve size. This geometric parameter change enables sufficient medium flowback while maintaining compact pump housing dimensions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The flap valve design utilizes three-dimensional flow patterns by allowing medium to pass through and around the valve in multiple directions, rather than relying solely on the valve opening area. This dimensional approach to flow management increases medium flowback capacity without requiring larger valve or housing dimensions

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If spring-loaded and weight-loaded poppet valves are used, then the valve can be positioned at specific angles to gravitational acceleration, but the installation position becomes constrained

Engineering Contradiction:

Improvevalve positioning reliabilityVSAvoidinstallation position flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the weight-loaded mechanism with a purely spring-loaded system. The spring provides the necessary force to counteract pressure differentials and position the valve disk, eliminating the need to account for gravitational acceleration. This mechanical substitution allows the valve to be installed in any orientation without requiring specific angular positioning relative to gravity, thereby improving installation flexibility while maintaining positioning reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 faster and quieter operation, reduces pump housing size, and allows for flexible installation positions, achieving shorter process times and efficient medium flowback without the need for large poppet valves.

Implementation Method 1

The valve has a spring-loaded valve body (28) which closes a passage opening (32) of the connecting channel (22), with the valve opening, in particular automatically, when a maximum pressure difference between the pressure side and the suction side is exceeded

Methodology Applied

Scientific EffectSpring force: Spring

Data Source

PatentEP2310684B1Vacuum pump in particular roots type pump

Publication Date: 2018.11.07 LEYBOLD AG

Figure 1~2
Figure 3~4

AI summary

The invention relates to a vacuum pump, in particular, a Roots type pump, comprising a lobe (12) arranged in a suction chamber (10). The pressure side (30) of the pump is connected to the suction side (20) by means of a connecting channel (22). A valve (24) is arranged in the connecting channel (22), which closes a through opening (32). On exceeding a set pressure difference between the pressure side (30) and the suction side (20) the valve opens automatically. In order to reduce the necessary space and to reduce the switching noise from the valve the valve body is embodied as a flap valve (28).