Pilot-Controlled Valve Assembly for Fast Blow Air Switching
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Solution Overview
Problem
Existing valve arrangements in blow molding machines require longer switching times for pneumatic switching of blowing air supply, which is inefficient for the multi-stage blow molding process, especially in stretch blow molding where rapid switching is crucial.
Innovation Solution
The proposed valve arrangement features a main valve with a switching piston and a control air control chamber connected via bores, allowing for quick opening and closing with a pilot valve and a closing element that enables large nominal diameters for switching on and small diameters for switching off, reducing dead volume and optimizing switching times without a complex booster stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional valve arrangement is used, then the structure is simple, but the switching time is too long for efficient blow molding production
Solution Approach 1:
The valve is divided into a main valve component and a pilot valve component. The pilot valve controls the control air supply to the main valve's switching piston, enabling rapid switching without requiring the entire valve structure to be complex. This segmentation allows the main valve to have a simple structure while achieving fast switching through the pilot valve's control mechanism.
Solution Approach 2:
Control air acts as an intermediary medium between the pilot valve and the main valve's switching piston. The pilot valve regulates the control air supply, which then acts on the switching piston to open or close the main valve. This intermediary mechanism enables rapid switching by controlling the air pressure that moves the switching piston, without requiring direct mechanical actuation of the main valve.
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 achieves faster switching times for the blow molding process, enabling quicker implementation of blowing air supply changes, which is essential for efficient production of plastic containers like PET bottles, by utilizing relatively large nominal widths for opening the main valve and small diameters for closing without a booster stage.
Implementation Method 1
The switching piston has a control surface for control air, which faces a control chamber of the valve housing and is designed to transmit to the switching piston a control force exerted by the control air
Implementation Method 2
The control air for the main valve can be introduced from the control air control chamber into the control chamber of the main valve via the at least one bore, which connects the control air control chamber to the control chamber in terms of flow
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
The invention relates to a valve arrangement (100) having a main valve (1) having a switching piston (2) guided in a valve housing (3), which switching piston (2) can be moved relative to the valve housing (3) between a first position, in which the main valve (1) is closed, and a second position, in which the main valve (1) is open. The switching piston (2) has a control surface (9), configured to face a control chamber (10) of the valve housing (3) and to transfer a control force onto the switching piston (2). According to the invention, at least one bore (21; 27, 28) connecting a control air switching chamber (20) to the control chamber (10) in terms of flow is provided, by way of which control air can be introduced into the control chamber (10) for closing the main valve (1), and by way of which the control chamber (10) can be vented when opening the main valve (1). By way of a control air bore (23) terminating in the control air switching chamber (20), control air can be introduced to the control air switching chamber (20), wherein a venting bore (24) terminating in the control air switching chamber (20) is provided, by way of which the control chamber (10) can be vented when the main valve (1) is opened.