Pneumatic Valve Sealing Geometry for Low Axial Force
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Solution Overview
Problem
Existing pneumatic valves used in blow-molding processes require high axial sealing forces, which limit their service life and operational cycles due to high sealing and acceleration forces.
Innovation Solution
A valve unit with minimized axial sealing forces is designed, featuring a dynamic process seal and a sealing edge configuration that allows for high surface pressure with low axial force, using a soft and hard material pairing for the sealing partners and optimizing the shape and size of the control chambers and seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high axial sealing forces are used in pneumatic valves, then sealing reliability is improved, but service life and operational cycles are reduced
Solution Approach 1:
The patent changes the material parameters of the sealing partners by using a soft material (e.g., elastomer) paired with a hard material (e.g., metal or hard plastic). This material parameter change allows the soft material to deform and conform to surface irregularities, achieving reliable sealing with significantly reduced axial sealing forces compared to hard-hard material pairings.
Solution Approach 2:
The patent employs composite material pairing where a soft sealing material (such as rubber or elastomer) is combined with a hard structural material (such as metal or rigid plastic). This composite approach leverages the compliance of the soft material to distribute sealing forces over a larger area and accommodate surface variations, thereby reducing the peak axial forces required while maintaining sealing effectiveness.
2Reliability
If high axial sealing forces are applied, then sealing performance is improved, but number of operational cycles is limited
Solution Approach 1:
By changing the material parameters to include a soft sealing material with high elasticity and conformability, the patent achieves effective sealing at lower axial forces. This parameter change reduces the mechanical stress on sealing components during each cycle, thereby extending the total number of operational cycles the valve can withstand before sealing degradation occurs.
Solution Approach 2:
The patent utilizes a flexible soft sealing material that can deform elastically during valve operation. This flexibility allows the sealing surface to adapt to pressure changes and minor misalignments without requiring high axial forces, reducing wear and fatigue on sealing components and enabling a higher number of operational cycles.
3Productivity
If rapid valve operation is required, then production efficiency is improved, but axial sealing forces must be minimized to extend service life
Solution Approach 1:
The patent changes the material parameters of the sealing interface to use a soft-had material pairing, which enables effective sealing at reduced axial forces. This allows the valve to operate rapidly with minimal force application, preventing wear accumulation from high forces while maintaining the speed required for efficient production.
Solution Approach 2:
The patent partially replaces the mechanical sealing approach (relying on high axial forces) with a material-based sealing approach (relying on soft material deformation and conformability). This substitution reduces dependence on high mechanical forces, enabling rapid operation without compromising service life.
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 valve unit achieves a long service life and high number of operational cycles with reduced axial sealing forces, enabling rapid operation and efficient use of compressed air in blow-molding processes.
Implementation Method 1
The sealing partners are designed with a soft and hard material pairing, wherein the soft sealing material is designed to achieve a seal with a small abutment surface. The soft material deforms elastically under pressure to conform to the sealing surface, creating an effective seal with minimized axial sealing forces.
Implementation Method 2
If a pressure is now applied to the control chamber, the operating piston is raised and the valve is opened. The control surface is larger than the difference between the lower and upper active surface in the closed state of the valve, creating a differential force that moves the piston with minimal axial sealing force.
Data Source
AI summary
A valve unit comprises an operating piston for closing and opening a connection between a process pressure input line and a process pressure output line, at least one control line and at least one control chamber for controlling the operating piston. The operating piston has a closing ring which in the closed state of the connection sealingly abuts a valve seat of the valve housing (or the valve housing has a closing ring which in the closed state of the connection sealingly abuts against a valve seat of the operating piston). The valve seat consists of a softer and more elastic material than a circumferential sealing edge abutting said valve seat. An annular sealing element is present which comprises the valve seat. The sealing element has the shape of a truncated cone with an outwardly widening base.