Ejector Backup for Tablet Press Negative Pressure Hold
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Solution Overview
Problem
Existing systems for maintaining negative pressure in sealed rooms of tablet presses or isolators fail to ensure prolonged negative pressure when the negative pressure source breaks down, leading to potential leaks and reduced sealing effectiveness.
Innovation Solution
The integration of an ejector with a venturi nozzle, connected to the sealed room, which generates negative pressure using compressed air, and a valve system that automatically activates the ejector upon breakdown of the fan or control system, ensuring continued negative pressure without leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fan is used as the negative pressure source, then negative pressure can be generated effectively, but the system fails when the fan breaks down
Solution Approach 1:
The ejector is pre-installed and connected to the sealed room, with all necessary components (venturi nozzle, compressed air connection) in place before failure occurs. The system is designed so that the ejector can immediately take over negative pressure generation when the fan fails, without requiring any post-failure assembly or configuration.
Solution Approach 2:
The ejector acts as an intermediary device that can replace the fan's function. It uses compressed air as an intermediate energy source to generate the negative pressure that would otherwise be provided by the fan's mechanical operation, thereby maintaining system functionality when the primary device fails.
2Reliability
If an ejector is added as backup, then reliability improves, but device complexity increases
Solution Approach 1:
The ejector system is merged with the existing fan system by connecting both devices to the sealed room's air intake. The control unit integrates monitoring of both devices and coordinates their operation, allowing them to function as a unified backup system rather than separate independent systems.
Solution Approach 2:
The control unit automatically detects fan failure and activates the ejector without requiring manual intervention. The system monitors its own operational status and self-regulates by switching from fan-only operation to ejector operation when failure is detected, maintaining negative pressure continuously.
3Loss of energy
If the valve is normally closed, then compressed air consumption is minimized, but the ejector cannot activate quickly in failure
Solution Approach 1:
The control unit continuously monitors the fan's operational status and uses this feedback to determine when to open the valve and activate the ejector. This closed-loop control ensures the valve remains closed during normal operation (minimizing compressed air consumption) but opens immediately when fan failure is detected (ensuring quick activation).
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 solution maintains negative pressure in the sealed room for a longer period, allowing personnel to safely exit the production area even during fan or control system failures, with minimal compressed air consumption and reduced risk of dust leakage.
Implementation Method 1
In the latter, a pumping effect is produced with the aid of a venturi nozzle, as is well known, by supplying a fluid sideways to the venturi nozzle, which produces a propulsive jet. The propulsive jet creates a negative pressure at the beginning of the venturi nozzle, which can be used for pumping purposes.
Data Source
AI summary
A device for generating a negative pressure in the sealed room of a tablet press and/or of an isolator, with a fan connected to the sealed room and an air opening towards the sealed room, wherein the intake side of an ejector is connected with the sealed room, the working fluid connection of which is connectable with a compressed air source via a valve, with a sensor which is connected to a negative pressure control unit which opens the valve when the sensor measures a pressure in the sealed room which is above a predetermined negative pressure value, a second valve being assigned to the fresh air inlet opening, which depending on the embodiment remains opened or is triggered and closed by the negative pressure control unit.