Volumetric Dosing Piston Seal with Elastic Lip Preload
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Solution Overview
Problem
Proportional volumetric dosing units face issues with permanent deformation of polymeric annular sealing lips due to plasticization, leading to a loss of sealing force and functionality over time.
Innovation Solution
Incorporating an elastic element made of elastomeric material to push the annular sealing lip against the cylinder, ensuring the seal's functionality even with material plasticization, and using a nonelastomeric polymeric material for the lip, with a locking device to maintain the elastic element's position and apply even pressure across the seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an annular sealing lip made of polymeric material is used to create a fluid seal between the piston and cylinder, then the seal can maintain contact with the cylinder through elastic bending deformation, but over time the deformation becomes permanent due to plasticization and the seal loses its sealing force
Solution Approach 1:
The patent introduces an elastic element that changes the physical state of the sealing system by providing continuous elastic force. This elastic element compensates for the plasticization of the polymeric sealing lip by maintaining the necessary contact pressure through its own elastic deformation, effectively reversing the degradation effect of plasticization over time
Solution Approach 2:
The elastic element acts as an intermediary between the piston and the sealing lip, providing the necessary force to maintain contact between the sealing lip and cylinder. This intermediary component protects the sealing lip from direct mechanical loading that causes plasticization while ensuring continuous sealing contact
2Reliability
If the elastic element directly contacts the cylinder to push the sealing lip, then the sealing force is maintained, but the service life is reduced due to increased wear on the cylinder
Solution Approach 1:
The sealing lip serves as an intermediary component between the elastic element and the cylinder. The elastic element pushes against the sealing lip, which in turn contacts the cylinder to create the seal. This arrangement protects the cylinder from direct contact with the elastic element, preventing wear and extending the cylinder's service life while maintaining effective sealing
Solution Approach 2:
The sealing system is segmented into distinct functional components: the elastic element provides force, the sealing lip provides the sealing interface, and the cylinder provides the housing. This segmentation allows each component to be optimized for its specific function and replaced independently if needed, extending the overall system life
3Stability of the object's composition
If the annular sealing lip is made of elastomeric material to improve elasticity, then the sealing contact is maintained, but the plasticization issue worsens due to the material's susceptibility to permanent deformation
Solution Approach 1:
The patent changes the material parameter of the sealing lip from elastomeric to nonelastomeric polymeric material. This nonelastomeric material has superior resistance to plasticization while the elastic element compensates for any reduced elasticity by providing the necessary contact force through its own elastic properties
Solution Approach 2:
The sealing system uses a composite approach combining two different polymeric materials: a nonelastomeric polymeric material for the sealing lip that resists plasticization, and an elastomeric material for the elastic element that provides elasticity and continuous contact force. This composite material strategy leverages the advantages of both material types
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 extends the service life of the seal by maintaining its functionality despite material plasticization and ensures a reliable fluid seal through even pressure distribution, enhancing the overall performance and longevity of the dosing unit.
Implementation Method 1
it comprises an elastic element which pushes the annular sealing lip against the cylinder
Implementation Method 2
which when inserted into the cylinder is elastically deformed by bending in contact with said cylinder. This elastic bending deformation generates a force that keeps a portion of the lip in constant contact with the cylinder
Data Source
AI summary
A proportional volumetric dosing unit (1) is described comprising a pump (25) provided with a piston (235) adapted to supply an auxiliary fluid to a motor (20) of the proportional volumetric dosing unit itself, which moves the piston (235) of the pump and is fluidly connected to an inlet conduit (10) of a main fluid and an outlet conduit (15) of a mixed fluid, said motor comprising a piston (30) slidably housed in a cylinder (100) of the motor and connected to the piston (235) of the pump to move it, wherein the piston (30) comprises an annular scaling lip (80) protruding from a top (55) of the piston (30), and an end portion thereof distal from the top of the piston is applied in contact to the cylinder (100) making a fluid seal, said proportional volumetric dosing unit being characterized in that it comprises an elastic element (130) which pushes the annular sealing lip (80) against the cylinder (100).