Parallel Valve Assembly for Stable Target Pressure Control
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Solution Overview
Problem
Existing fluidic control systems, particularly in applications like blow molding and laser cutting, face challenges in maintaining specific target or minimum pressures due to limitations in proportional valve performance, especially when pressurizing open volumes or providing sufficient cooling air, and lack effective means for early detection of pressure deviations.
Innovation Solution
A valve assembly with a proportional valve and a parallel switching valve, controlled by a digital device that calculates the maximum achievable working pressure based on current system states and automatically opens the switching valve when the target pressure is imminent, incorporating a sensor system and technical calculation models to account for pneumatic resistance, outflow characteristics, and supply pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a proportional valve with larger maximum opening cross section is used, then the maximum achievable pressure increases, but the control accuracy in the performance range deteriorates
Solution Approach 1:
The system divides the pressure control function into two segments: a proportional valve for continuous control in the normal range, and a switching valve for additional pressure support when maximum pressure is required. This segmentation allows each valve to operate in its optimal range, maintaining control accuracy while achieving higher maximum pressure.
Solution Approach 2:
The system dynamically switches between proportional valve-only operation and combined proportional valve plus switching valve operation based on real-time pressure requirements. The controlling device continuously monitors pressure and activates the switching valve only when the proportional valve approaches its maximum opening, optimizing both control accuracy and maximum pressure achievement.
2Stress or pressure
If a switching valve is added in parallel to increase maximum system performance, then the maximum achievable pressure increases, but the device complexity increases
Solution Approach 1:
The system extracts the pressure sensing function from a separate sensor system and integrates it directly into the controlling device through an internal pressure sensor. This eliminates the need for external sensor systems and their associated complexity while maintaining the ability to detect pressure deviations and trigger the switching valve.
Solution Approach 2:
The controlling device merges multiple functions: it controls the proportional valve, monitors pressure via an internal sensor, calculates maximum achievable pressure using technical models, and triggers the switching valve. This consolidation into a single control unit reduces overall system complexity compared to having separate components for each function.
3Measurement precision
If a sensor system is provided for early detection of pressure deviations, then the control accuracy improves, but the device complexity increases
Solution Approach 1:
The pressure sensing function is extracted from external sensor systems and integrated directly into the controlling device through an internal pressure sensor connected to the fluid supply line. This integration eliminates the need for separate sensor systems and their associated structural complexity while maintaining early detection capability.
Solution Approach 2:
The controlling device performs self-monitoring of pressure conditions through its integrated pressure sensor, eliminating the need for separate detection systems. The device automatically detects pressure deviations, calculates maximum achievable pressure using internal models, and triggers appropriate valve actions without external intervention or additional sensor systems.
Data Source
AI summary
A valve assembly includes a proportional valve having an opening cross section that can be continuously varied by an actuator; a sensor for sensing the valve output pressure; a digital regulating device; and a switching valve disposed parallel to the proportional valve. The opening cross section of the switching valve is smaller than the maximum opening cross section of the proportional valve. The regulating device is programmed (i) to automatically calculate, at runtime, using the currently given valve output pressure and the current position of the actuator, the maximum working pressure achievable at the maximum opening of the proportional valve with the valve, (ii) and to additionally open the switching valve when the computed maximum achievable working pressure falls below a predefinable target working pressure by a definable deviation value.