Vacuum Pump Flood Valve With Captive Screw and Controlled Airflow

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Solution Overview

Problem

Existing vacuum pumps, particularly turbomolecular vacuum pumps, face issues with venting screws that can be unscrewed and lost, potentially causing system shutdowns, and flood screws that can jam, damaging the thread of the flood opening.

Innovation Solution

A flood valve with a valve housing and a captively held valve element, featuring a screw shaft with a valve disk and axial channels for controlled airflow, preventing accidental unscrewing and ensuring reliable sealing and adjustable airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple venting screw is used to close the venting port, then the device complexity is reduced and ease of manufacture is improved, but the reliability deteriorates because the venting screw can be accidentally unscrewed and lost

Engineering Contradiction:
Improveventing valve structureVSAvoidventing screw retention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The venting valve is divided into two main components: a valve housing and a separate valve element. The valve element can be independently screwed into the valve housing, providing a modular design that reduces overall complexity while improving reliability through captive retention mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The valve element is nested within the valve housing, with the valve element's external thread engaging with the valve housing's internal thread. This nesting arrangement ensures the valve element remains captive within the housing while allowing for easy installation and removal when needed.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If a venting screw is used, then the device complexity is reduced, but the reliability worsens because the flood screw can become jammed and potentially damage the thread of the flood opening

Engineering Contradiction:
Improveventing valve structureVSAvoidthread integrity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

By separating the valve element from the valve housing as distinct components, the design allows the valve element to be independently replaced if it becomes jammed, preventing damage to the valve housing's internal thread and maintaining system reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The valve element is designed as a replaceable component that can be easily screwed in and out. If the valve element becomes jammed or damaged, it can be replaced without damaging the more expensive valve housing, effectively using a disposable-like approach to protect the main structure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If a venting screw is used, then ease of operation is improved for simple opening/closing, but reliability deteriorates due to the risk of complete unscrewing and loss

Engineering Contradiction:
Improveventing port opening/closingVSAvoidventing screw retention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The valve element is designed to be dynamically adjustable along the threaded bore, allowing it to be positioned at different axial locations. This dynamic positioning capability enables easy opening and closing operation while the threaded engagement prevents complete unscrewing and loss.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The axial position of the valve element can be changed by rotating it along the threaded bore. This parameter change (axial position) controls the opening/closing state of the venting port, providing ease of operation while the thread geometry prevents complete removal.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4328468B1Flow valve and vacuum pump equipped with such a flow valve
Publication Date: 2025.10.01 PFEIFFER VACUUM TECH AG
  • EP4328468B1 patent drawingFigure 1
  • EP4328468B1 patent drawingFigure 2
  • EP4328468B1 patent drawingFigure 3

AI summary

The present invention relates to a flood valve (10) for opening and closing a flood port in the housing of a vacuum pump. The flood valve (10) comprises a valve housing (12) for receiving in a flood port of a vacuum pump and a valve element (14) received by the valve housing (12). The valve housing (12) is penetrated by a through-bore (16) extending from a first axial end face (17) to a second axial end face (18) of the valve housing (12) and having an internal thread (20). The valve element (14) has a screw shank (22) with an external thread (24) by which the valve element (14) is screwed into the internal thread (20) of the through-bore (16).The screw shaft (22) has at a first end (25) a rotary drive (28) for actuating the valve element (14) to change the axial position of the valve element (14) relative to the valve housing (12) and at an opposite second end (26) a valve disc (30) which, in a first axial position of the valve element (14), rests against the second end face (18) of the valve housing (12) to seal the through-bore (16) and, in a second axial position of the valve element (14), has a distance relative to the second end face (18).