Adhesive Dispensing Membrane Seal With Pressure Compensation
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Solution Overview
Problem
Devices for dispensing flowable media, such as hot melt adhesives, face challenges with dynamic and static seals, where high pressures can lead to membrane damage and wear, resulting in unreliable operation and potential safety failures.
Innovation Solution
Incorporating a pressure medium in a secondary cavity to balance the pressure load on the membrane, reducing the risk of damage and wear, and using a thermoplastic membrane with specific design features to maintain precise switching behavior and extend service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a dynamic seal is used to prevent flowable medium penetration, then the seal can accommodate rod movement, but the seal wears out during long-term operation and loses sealing effect
Solution Approach 1:
The patent employs a disposable seal cartridge containing the seal, which is replaced periodically rather than maintained. This allows the seal to perform its function during the cartridge's service life, then be discarded and replaced, avoiding the wear problem while maintaining operational capability.
Solution Approach 2:
The seal is extracted from the main device body and placed in a separate, replaceable cartridge. This separation allows the seal to be easily replaced without affecting the rod mechanism or other device components, resolving the contradiction between movement capability and sealing reliability.
2Reliability
If a static seal in the form of a membrane is used to prevent flowable medium penetration, then the seal provides reliable sealing, but high pressure load on the membrane can lead to damage during long-term operation
Solution Approach 1:
The patent introduces a pressure medium into the second cavity that exerts counter-pressure on the membrane from the opposite side. This counterbalances the high pressure load from the flowable medium, reducing the net stress on the membrane and preventing damage during long-term operation while maintaining reliable sealing.
Solution Approach 2:
The patent changes the pressure parameter in the second cavity by introducing a pressure medium. This parameter change creates a balanced pressure state that protects the membrane from excessive stress while maintaining the sealing function.
3Manufacturing precision
If high pressure is applied to the flowable medium for precise dispensing control, then the dispensing precision is improved, but the membrane seal becomes more susceptible to damage and wear
Solution Approach 1:
The pressure medium in the second cavity provides counter-pressure that balances the high pressure from the flowable medium. This allows high pressure to be applied for precise dispensing control without subjecting the membrane to excessive net stress, thereby extending membrane lifespan while maintaining dispensing precision.
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 enables reliable long-term operation at high pressures with precise control and extended membrane lifespan, independent of pressure fluctuations, ensuring consistent and safe dispensing of flowable media.
Implementation Method 1
a pressure medium acting on the membrane being arranged in the second cavity, wherein the pressure medium acts on the membrane with a force at least partially compensating for the force resulting from the pressure of the flowable medium
Implementation Method 2
the membrane divides the interior space into a first cavity and a second cavity, wherein the membrane separates the first cavity from the second cavity in a fluid-tight manner
Data Source
Figure 1
AI summary
The present invention relates to a device (1) for dispensing a flowable medium, wherein the flowable medium is preferably an adhesive, in particular a hot melt adhesive or a melt adhesive. The present invention further relates to a method for operating such a device (1). The device (1) comprises a housing with an interior space and a rod (5) mounted in the housing, wherein the rod (5) is movable between a first end position and a second end position in an axial direction (Z) and vice versa by means of an actuator.Furthermore, the device (1) comprises a membrane (7), wherein the rod (5) penetrates the membrane, wherein the membrane (7) is radially sealed on the outside in the housing and radially sealed on the inside in the rod (5), wherein the membrane (7) divides the interior into a first cavity (2) and a second cavity (3), wherein the membrane (7) separates the first cavity (2) from the second cavity (3) in a fluid-tight manner, wherein the first cavity (2) serves to receive the flowable medium. The device (1) has at least one channel (11) opening into the first cavity (2) through which the flowable medium can flow into the first cavity (2) and a discharge opening (4) opening into the cavity (2) for dispensing the flowable medium, wherein the rod (5) has a sealing section (6), wherein the sealing section (6) closes the discharge opening (4) in the first end position and is arranged spaced apart from the discharge opening (4) in the second end position.In the second cavity (3) a pressure medium acting on the membrane (7) is arranged.