Vacuum Rotary Slide Pump Valve Pressure Equalization

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Solution Overview

Problem

Vacuum rotary vane pumps face issues with oil accumulation in the suction chamber upon shutdown, leading to increased torque, noise, and risk of oil entering the vacuumed space when restarted, requiring effective pressure equalization to prevent damage and contamination.

Innovation Solution

A valve device with a compensating channel connects the suction chamber to an area of atmospheric pressure, using a mixture of oil and air to seal off the suction chamber and ensure rapid pressure equalization, integrated into the valve device to prevent backflow and facilitate noise reduction through controlled emulsification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a valve device with compensating channel is integrated into the valve device, then pressure equalization speed is improved and oil accumulation is prevented, but device complexity increases

Engineering Contradiction:
Improvepressure equalization timeVSAvoidvalve device structure
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The compensating channel is integrated directly into the valve device structure, merging the pressure equalization function with the existing valve components. This eliminates the need for separate compensating mechanisms while achieving rapid pressure equalization when the pump stops, preventing oil accumulation in the suction chamber.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The compensating channel acts as an intermediary pathway that allows atmospheric pressure to enter the suction chamber through the valve device. This mediator structure enables controlled pressure equalization without requiring complex separate systems, facilitating quick oil displacement and chamber pressurization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a separate bore with valve device is provided (US Pat. No. 3,301,474), then pressure equalization is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvepressure equalization reliabilityVSAvoidvalve device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the compensating channel function directly into the existing valve device structure rather than providing a separate bore with independent valve control. This integration maintains reliable pressure equalization while significantly simplifying the overall device structure and reducing manufacturing complexity compared to separate valve mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The valve device is designed to serve multiple functions: it controls the discharge channel and simultaneously provides the compensating channel for pressure equalization. This multi-functional design eliminates the need for separate valve devices dedicated solely to pressure equalization, reducing overall system complexity while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If the suction chamber is not pressurized after shutdown, then oil can enter the space to be vacuumed, but avoiding pressurization mechanisms increases device simplicity

Engineering Contradiction:
Improveoil contamination riskVSAvoidpressure equalization system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The compensating channel serves as an intermediary pathway that automatically allows atmospheric pressure to enter the suction chamber through the valve device structure. This passive mediator mechanism prevents oil contamination by equalizing pressure without requiring active control systems or complex pressurization devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses its own valve device structure to provide the compensating function, making the system self-sufficient for pressure equalization. The valve device itself facilitates the inflow of atmospheric pressure to prevent oil backflow, eliminating the need for external or additional complex pressurization systems.

Inventive Principle:
Principle #25Self-service

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 solution effectively prevents oil accumulation, reduces noise by ensuring good emulsification, and allows for quick pressure equalization in the suction chamber, minimizing torque and damage risks upon restart, while being cost-effective and retrofittable to existing pumps.

Implementation Method 1

air is sucked in through the compensating channel due to the lower pressure in the suction chamber. This leads to rapid pressure equalization in the suction chamber

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 2

a valve device being arranged between the oil chamber and the discharge channel. The valve device serves to prevent medium from flowing back

Methodology Applied
Scientific EffectBackflow prevention: Valve

Implementation Method 3

For lubrication and to ensure a good seal of the slide on the inner wall of the suction chamber, there is always a certain amount of oil to form an oil film in the suction chamber

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 4

Due to the centrifugal force, the slides are pressed against an inner wall of the suction chamber during a rotation of the rotor

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2836722B1Vacuum-type rotary slide pump
Publication Date: 2021.11.03 LEYBOLD AG
  • EP2836722B1 patent drawingFigure 1~2
  • EP2836722B1 patent drawingFigure 3~4

AI summary

A vacuum-type rotary slide pump has a pump chamber (12) in a housing (10). A rotor (14) is eccentrically mounted in the pump chamber (12). Slides (18) are connected in a displaceable manner to the rotor (14). Furthermore, a discharge duct (30) is connected to the pump chamber (12) and to an oil chamber (32). Between the discharge duct (30) and the oil chamber (32) there is arranged a valve device (38) for preventing a return flow of medium from the oil chamber (32) into the pump chamber (12). According to invention, at least one compensation duct (50, 72) is provided which is connected to the discharge duct (30) and to the oil chamber (32) and which is integrated into the valve device (38).