Composite Pump Membrane Sealing for Secure Insert Bonding
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Solution Overview
Problem
Composite membranes in membrane pumps, particularly those made from thermoplastic elastomers, face issues with forming a sufficient bond with metal inserts, leading to detachment under high surface forces and loads, which allows compressed air to enter the gap and accelerate the detachment process, especially in larger membrane diameters.
Innovation Solution
A composite membrane design where the insert extends through an opening in the lower wall and surrounds it in a sealing section, forming a positive connection with the lower wall, and an active sealing geometry is created using thickening and circumferential grooves to prevent radial movement and air entry, ensuring a secure bond and effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic elastomers are used for the elastomer body to simplify manufacturing, then ease of manufacture is improved, but bonding strength with metal insert deteriorates
Solution Approach 1:
The lower wall is designed with a localized thickening in the sealing section that engages with circumferential grooves on the insert. This local structural modification creates a mechanical interlock specifically at the bonding interface, providing form-fitting connection strength without requiring changes to the entire elastomer body or additional adhesive systems.
Solution Approach 2:
The solution combines the thermoplastic elastomer body with a metal insert featuring circumferential grooves, creating a composite structure where each material contributes its advantageous properties. The mechanical interlock between the elastomer thickening and metal grooves provides bonding strength comparable to adhesive systems while maintaining the manufacturing simplicity of thermoplastic elastomers.
2Strength
If additional adhesive layers are used to bond elastomer body to insert, then bonding strength is improved, but device complexity increases
Solution Approach 1:
The bonding function and sealing function are merged into a single integrated structure. The thickening of the lower wall serves dual purposes: providing mechanical interlock for bonding and creating the sealing geometry. The circumferential grooves on the insert similarly serve both bonding and sealing functions, eliminating the need for separate adhesive layers and reducing overall device complexity.
Solution Approach 2:
The sealing section structure performs multiple functions simultaneously: it provides mechanical interlocking for bonding, creates compression sealing against air ingress, and maintains structural integrity. This multi-functional design replaces what would otherwise require separate adhesive, sealing, and structural components.
3Ease of manufacture
If openings are provided in the insert for liquid elastomer injection, then ease of manufacture is improved, but compressed air penetration increases
Solution Approach 1:
The circumferential grooves on the insert, which could potentially channel air, are instead designed to work with the elastomer thickening to create an active sealing geometry. The grooves provide mechanical interlocking while the thickening compresses against them to seal the interface, converting what could be air channels into sealing surfaces that actively prevent air ingress.
4Productivity
If larger membrane diameters are used to meet flow requirements, then productivity is improved, but bonding reliability deteriorates
Solution Approach 1:
The form-fitting connection through the thickening and circumferential grooves is built into the structure during manufacturing, creating pre-loaded mechanical interlocking and sealing contact. This preliminary structural action ensures bonding reliability is established before operational loads are applied, preventing detachment even in large-diameter membranes subject to high surface forces.
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 positive connection and active sealing geometry effectively absorb radial forces, prevent elastomer body detachment, and significantly reduce compressed air entry, ensuring a permanent bond and enhanced operational resistance without the need for additional adhesive layers.
Implementation Method 1
the lower wall (6b) in the sealing section (10) has a thickening (11) surrounding the opening (9), which engages on both sides in a circumferential groove (12a, 12b) of the insert (8)
Implementation Method 2
the insert (8) and the lower wall (6b) in the sealing section (10) are positively connected to one another with respect to a force acting parallel to the lower wall (6b), in that they are connected in a form-fitting manner
Implementation Method 3
The elastomeric body is formed from an elastomeric material, rubber usually being used and the insert being vulcanized into the elastomeric body to form a stable adhesive bond
Implementation Method 4
by applying heat, they can be plastically deformed and thus given almost any desired shape
Data Source
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AI summary
A composite diaphragm for diaphragm pumps comprising a disc-shaped elastomer body (1) having a circumferential rim (2) with a clamping surface (3), a base (4), and a flexible diaphragm section (5) connecting the circumferential rim (2) to the base (4), wherein the base (4) has an upper and a lower wall (6a, 6b) and a chamber (7) formed between the walls (6a, 6b), and wherein an insert (8) is arranged at least partially between the walls (6a, 6b). According to the invention, the insert (8) extends through an opening (9) in the lower wall (6b) and surrounds the lower wall (6b) in a sealing section (10), wherein the insert (8) and the lower wall (6b) are positively connected to each other in the sealing section (10) with respect to a force acting in the radial direction (R).