Multi-Stage Vacuum Generator with Differential Pressure Venting
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Solution Overview
Problem
Multi-stage ejector vacuum generators face challenges in quickly releasing vacuum with low air requirements, especially under conditions of short cycle times and frequent blow-off processes, due to high compressed air consumption and inefficient venting mechanisms.
Innovation Solution
Incorporation of a shut-off valve and a differential pressure ventilation valve connected via a compressed air duct, allowing for airtight closure of the air outlet and controlled ventilation to reduce compressed air usage, with a configuration that utilizes a compressed air pulse for both shutting off the vacuum and venting the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If compressed air is continuously applied to break the vacuum in single-stage ejectors, then the vacuum can be released quickly, but the compressed air consumption increases considerably
Solution Approach 1:
The ejector is divided into multiple stages with several nozzles arranged in series, where compressed air is supplied sequentially through each stage. This segmentation allows the vacuum to be broken in controlled steps rather than requiring continuous high-volume compressed air application, reducing overall air consumption while maintaining release speed.
Solution Approach 2:
Instead of continuous compressed air application, the system uses periodic action through the multi-stage sequential air supply and the automatic cycle of the differential pressure vent valve. The vent valve opens periodically when pressure differential conditions are met, creating rhythmic ventilation cycles that efficiently break the vacuum without continuous air consumption.
2Speed
If a free air outlet is used in multi-stage ejectors to ventilate the vacuum chamber, then the vacuum can be released, but the compressed air consumption increases due to the need for additional forced ventilation
Solution Approach 1:
The differential pressure vent valve automatically opens and closes based on the pressure differential between the vacuum chamber and ambient environment. When the chamber pressure rises during the breaking vacuum process, the valve opens to provide ventilation without requiring external control or additional compressed air. The system serves itself by using its own pressure changes to trigger the ventilation action.
Solution Approach 2:
The differential pressure vent valve acts as an intermediary mechanism between the vacuum chamber and the environment. It mediates the pressure equalization process by opening only when necessary (when pressure differential conditions are met), providing controlled ventilation that prevents excessive compressed air consumption while ensuring adequate vacuum release speed.
3Loss of time
If the air outlet is closed quickly in single-stage ejectors to reduce vacuum, then workpieces can be released quickly, but the energy consumption remains high due to poor vacuum generation efficiency
Solution Approach 1:
The multi-stage nozzle arrangement segments the vacuum generation and breaking process into sequential phases. Each stage contributes to the overall pressure change, allowing the vacuum to be broken efficiently through cumulative pressure changes rather than requiring a single high-energy impulse, thus reducing total air consumption while maintaining release time.
Solution Approach 2:
The system changes pressure parameters sequentially through multiple stages rather than applying a single large pressure change. The differential pressure vent valve responds to specific pressure threshold conditions, creating a controlled parameter transition that breaks the vacuum efficiently without excessive energy input.
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
This configuration reduces the energy requirement by up to 70% by minimizing unnecessary compressed air usage and enhancing the speed of the venting process, allowing for efficient release of workpieces while maintaining vacuum efficiency.
Implementation Method 1
the vent valve is designed as a differential pressure valve. In this case, this means that the vent valve remains closed under negative pressure because the ambient pressure, acting via a connection, is applied to a movable sealing element on the other side
Implementation Method 2
a multi-stage ejector with several nozzles arranged in series, through which an airflow supplied via a compressed air connection is directed at high speed to an air outlet, so that a negative pressure can be generated in a communicating space surrounding the nozzles
Data Source
Figure 1
Figure 2
AI summary
A vacuum generator has a multi-stage ejector with several nozzles arranged in series. A high-velocity airflow, supplied via a compressed air connection (22), is directed through the nozzles to an air outlet (28), thus generating a vacuum in a communicating space (20) surrounding the nozzles. To enable rapid vacuum release at low air demand based on the multi-stage ejector, a shut-off valve (32) is provided in the air outlet (28). This valve allows the air outlet (28) to be sealed airtight. The space (20, 30) in which the vacuum is generated has a ventilation opening (66) that is closed by a ventilation valve. This ventilation valve, in conjunction with the shut-off valve (32), opens a ventilation channel (66) to ventilate the space (20, 30) in which the vacuum is generated.