Vacuum Drawer Sealing Bar Preload Clamping for Uniform Contact
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Solution Overview
Problem
The existing sealing bars for vacuum drawers face issues with uniform contact of the welding wire, leading to potential overheating and damage due to heat-induced lengthening, which cannot be consistently prevented by previous solutions.
Innovation Solution
The sealing bar features a welding wire fastened to the base support with a preload using clamping connections, ensuring uniform contact and heat dissipation, even during lengthening, through indirect or direct clamping at one or both sides, with clamping means providing a lever or wedge effect for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the welding wire is fastened to the base support without preload, then the structure is simple, but uniform contact cannot be ensured leading to local overheating
Solution Approach 1:
The welding wire is pre-tensioned (preloaded) before operation to establish uniform contact pressure with the base support. This preliminary action ensures that even when the wire expands due to heat during welding, the contact pressure remains sufficient to prevent local overheating and ensure reliable heat dissipation throughout the wire's length.
Solution Approach 2:
The mechanical parameter of the welding wire changes from a loose state to a pre-tensioned state with specific preload force. This parameter change ensures uniform contact pressure distribution along the wire's length, transforming the contact condition from non-uniform (causing overheating) to uniform (ensuring reliable heat dissipation).
2Reliability
If the welding wire is rigidly fixed to prevent lengthening, then contact uniformity is maintained, but the wire cannot accommodate heat-induced expansion
Solution Approach 1:
The fastening system transitions from a rigid fixed connection to a dynamic spring-like connection that can accommodate changes in wire length. The spring element provides a flexible mechanical connection that maintains constant contact pressure while allowing the wire to expand and contract in response to temperature changes during operation.
Solution Approach 2:
The design explicitly accounts for thermal expansion of the welding wire by incorporating a spring element that compensates for length changes. The spring's mechanical properties are selected to match the thermal expansion characteristics of the wire, ensuring that contact pressure is maintained throughout the wire's length even as it expands due to heat-generated lengthening.
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 solution ensures uniform contact and heat dissipation along the welding wire's length, preventing overheating and damage, while allowing for flexible attachment and easy electrical connection, maintaining effective sealing performance during vacuuming operations.
Implementation Method 1
The bag is sealed due to the heat development by supplying the required welding energy
Implementation Method 2
Since a uniform contact may not be able to be ensured under certain circumstances on a heat-induced lengthening of the welding wire
Data Source
AI summary
The invention relates to a sealing bar for a vacuum drawer for vacuuming food, having a base support which comprises at least one welding wire extending in the longitudinal direction over the surface, with the welding wire being fastened to the base support by means of a clamping connection at one side or at both sides.