Switching Piston Valve Sealing With Low Axial Force
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Solution Overview
Problem
Existing pneumatic valve units in blow molding processes require high axial sealing forces, which limit their service life and switching cycles due to large control volumes and kinetic energies, making them inefficient and costly.
Innovation Solution
A valve unit with a dynamic process seal and a sealing edge designed as a circumferential sealing edge, using a softer material for the valve seat and a harder material for the sealing edge, minimizing axial sealing forces and allowing for bidirectional sealing at 40 bar with low axial force, and utilizing pilot valves with small nominal diameters for quick operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pneumatic valve units are used with large control volumes, then sealing reliability is achieved, but service life and switching cycle speed are reduced due to high axial sealing forces and kinetic energies
Solution Approach 1:
The invention changes the material parameters of the sealing components by using a softer material for the valve seat and a harder material for the sealing edge, reversing the conventional material assignment. This parameter change allows for reduced axial sealing forces while maintaining sealing reliability, thereby extending service life and enabling faster switching cycles
2Reliability
If conventional pneumatic valve units operate with high axial sealing forces, then sealing effectiveness is maintained, but switching speed and service life are limited due to large kinetic energies
Solution Approach 1:
The invention changes the material hardness parameters and sealing geometry to reduce the axial force required for sealing. The softer valve seat material deforms to conform to the harder sealing edge, creating an effective seal with lower axial forces, which reduces kinetic energy and increases switching speed
3Stress or pressure
If pilot valves with large nominal diameters are used to control large control volumes, then sufficient control pressure is achieved, but response time increases and device complexity rises
Solution Approach 1:
The invention extracts the large control volume requirement by using smaller control volumes that are sufficient for the reduced axial sealing forces. This allows the use of pilot valves with smaller nominal diameters, which have shorter response times and lower device complexity, while still achieving the necessary control pressure for reliable sealing
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
The solution reduces axial sealing forces, increases the service life, and enables high-speed switching cycles while maintaining effective sealing, allowing for efficient operation with lower operational costs and increased reliability.
Implementation Method 1
The dynamic process seal is designed such that its sealing diameter corresponds to the inner diameter of the switching piston, creating a pressure-balanced sealing interface that eliminates process pressure-dependent axial forces
Implementation Method 2
The dynamic process seal is formed by an elastomeric sealing ring that deforms elastically to maintain sealing contact under varying pressure conditions
Data Source
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AI summary
A valve unit comprises a valve housing (1) with a process pressure inlet line (31), a process pressure outlet line (32), and a process guide shaft (10). Furthermore, a switching piston (2) for closing the valve, a first and a second control line (50, 60), and a first and a second control chamber (40, 41) for controlling the switching piston (2) are provided. The switching piston (2) is axially displaceable within the process guide shaft (10) and is sealed by means of a dynamic process seal. It has a sealing ring which, in the closed state of the connection, abuts a valve seat (700) of the valve housing (1) to form a seal. The sealing ring is designed as a circumferential sealing edge (250), wherein the valve seat (700) is made of a softer and more elastic material than the sealing edge (250) abutting it.The circumferential sealing edge has a diameter (250) that corresponds to a guide diameter of the dynamic process seal. The valve unit according to the invention exhibits low axial forces and thus enables a long service life with a high number of switching cycles.