Controllable Valve Pressure Control for Plastic Preform Expansion
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Solution Overview
Problem
Existing methods for forming plastic preforms into containers face significant control tolerance deviations due to variations in valve and dome pressure regulator conditions, leading to inconsistent pressures and material distribution, especially during short air demands and disruptive events like bottle bursts.
Innovation Solution
A method and device that continuously monitor and compare actual pressure with target pressure in a compressed air reservoir, using a controllable valve to adjust and maintain desired pressure levels by calculating a correction value based on the difference, and using this information to control the valve, ensuring consistent air supply and minimizing pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional valve and dome pressure regulator control systems are used, then the system structure is simple, but control tolerance deviations are significant (up to 4 bar) leading to inconsistent pressure
Solution Approach 1:
The patent implements a feedback control system where a pressure sensor continuously monitors the actual pressure in the compressed air reservoir and feeds this information back to a control unit. The control unit compares the actual pressure with the target pressure and adjusts the valve actuation accordingly to maintain pressure consistency, thereby resolving the contradiction between simple structure and pressure precision.
Solution Approach 2:
The patent replaces the purely mechanical valve control system with an electronically controlled system. The control unit processes pressure feedback signals and electronically actuates the valve, substituting mechanical linkage with electronic control to achieve higher pressure consistency while managing system complexity through electronic integration.
2Stability of the object's composition
If passive valve and dome pressure regulator systems are used, then the device complexity is low, but pressure fluctuations are significant during air demand variations and disruptive events
Solution Approach 1:
The feedback control system continuously monitors pressure and actively adjusts valve actuation in response to pressure deviations caused by varying air demands or disruptive events like bottle bursts. This active feedback mechanism maintains pressure stability despite dynamic operating conditions, resolving the contradiction between low device complexity and high pressure stability.
Solution Approach 2:
The control system anticipates pressure drops by actively adjusting valve timing and duration based on real-time pressure feedback, performing preliminary corrective actions before significant pressure fluctuations occur, thereby maintaining stability without requiring overly complex passive pressure compensation mechanisms.
3Reliability
If new valves with higher internal friction are used, then the valve is in good technical condition, but control tolerance and response time are longer
Solution Approach 1:
The patent implements dynamic valve control where the actuation timing and duration are continuously adjusted based on real-time pressure feedback. This dynamic adjustment compensates for the higher internal friction of new valves by optimizing the actuation parameters, thereby maintaining reliable valve operation while improving effective response time through adaptive control.
Solution Approach 2:
The control system changes operational parameters (valve actuation timing, duration, and frequency) based on feedback from pressure sensors and knowledge of valve technical condition. This parameter optimization allows new valves with higher friction to achieve acceptable response times by adjusting control parameters rather than relying solely on mechanical valve characteristics.
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 approach effectively compensates for control tolerance deviations, maintaining consistent container quality by actively adjusting valve operations based on real-time pressure data, reducing the impact of wear and other factors, and enabling better material distribution and reduced defective containers.
Implementation Method 1
a momentary actual pressure, in particular an actual pressure within the pressure reservoir (in particular using a pressure sensor) be determined
Implementation Method 2
The valve translates the electrical signal into a pneumatic pressure, the control pressure for a dome pressure regulator
Implementation Method 3
plastic preforms are first heated and then formed into plastic containers, such as plastic bottles, by applying compressed air
Data Source
Figure 1
AI summary
Method for forming plastic preforms into plastic containers (20), wherein the plastic preforms (10) are transported along a predetermined transport path and are supplied with a flowable medium and expanded during this transport, wherein a controllable valve (65) of a reduction station (6) controls the supply of the flowable medium to a compressed air reservoir (74), in particular an annular channel, and wherein a target pressure is specified with which the compressed air reservoir (74) is supplied, wherein this target pressure is taken into account when controlling the valve (65) of the reduction station (6), characterized in that an actual pressure is determined and this actual pressure is compared with the target pressure and a correction value is determined from this comparison, which is taken into account and/or used in the control of the valve (65).